Page

Title

Author

Abstract

Keywords

In the first part of the paper, Computational Fluid Dynamics analysis of the
combusting flow within a high-swirl lean premixed gas turbine combustor andover the 1st row nozzle guide vanes is presented. In this analysis, the focus of
the investigation is the fluid dynamics at the combustor/turbine interface andits impact on the turbine. The predictions show the existence of a highlyrotating vortex core in the combustor, which is in strong interaction with theturbine nozzle guide vanes. This has been observed to be in agreement with

1-9

10-23

24-32

A. C. Benim, M. P. Escudier, P. J. Stopford, E.

Flows in Gas Turbine Combustors

Buchanan, K. J. Syed

Control of Shock-Wave/Bound-Layer Interactions by
Bleed

T. I-P. ShihThe Development of Protocols for Equitable Testingand Evaluation in Ocean Energy - A Three-Year
StrategyDavid M Ingram, Jose Luis Villate, Cyrille Abonnel,
Cameron Johnstone

38-46

Cavitation Instabilities of Hydrofoils and Cascades

Yoshinobu Tsujimoto, Satoshi Watanabe, Hironori
Horiguchi

57-63

64-75

initiated, with the aim of validating the predictive capability of currentlyURANS, RSM, LES, DES
available modelling procedures for turbulent swirling flows near the
sub/supercritical vortex core transition. In the second part of the paper, results
are presented which analyse such transitional turbulent swirling flows in two
different laboratory water test rigs. It has been observed that turbulent swirlingflows of interest are dominated by low-frequency transient motion of coherent
structures, which cannot be adequately simulated within the framework ofsteady-state RANS turbulence modelling approaches. It has been found that
useful results can be obtained only by modelling strategies which resolve thethree-dimensional, transient motion of coherent structures, and do not assume
a scalar turbulent viscosity at all scales. These models include RSM based
URANS procedures as well as LES and DES approaches.

The development of pre-set wavelength Görtler vortices are studied in theboundary-layer flows on concave surfaces of 1.0 and 2.0 m radius of curvature.
The wavelengths of the vortices were pre-set by thin wires of 0.2 mm diameter
placed 10 mm upstream and perpendicular to the concave surface leadingedge. Velocity contours were obtained from velocity measurements using asingle hot-wire anemometer probe. The most amplified or dominant
wavelength is found to be 15 mm for free-stream velocity of 2.1 m/s and 3.0
Flows over Concave Surfaces: Development of Pre-set
m/s on the concave surface of R = 1 m and 2 m, respectively. The velocity
Görtler vortices, pre-set wavelength, concave surface,
S. H. Winoto, Tandiono, D. A. Shah, H. Mitsudharmadi
Wavelength Görtler Vortices
contours in the cross-sectional planes at several streamwise locations show the boundary-layer flow
growth and breakdown of the vortices. Three different regions can be
identified based on the growth rate of the vortices. The occurrence of asecondary instability mode is also shown in the form of mushroom-likestructures as a consequence of the non-linear growth of the Görtler vortices.
By pre-setting the vortex wavelength to be much larger and much smaller
than the most amplified one, the splitting and merging of Görtler vortices canbe respectively observed.

33-37

47-56

Vol. 1, No.
1,
OctoberDecember,
2008

Computational Investigation of Turbulent Swirling

the temperature indicated by thermal paint observations. The results suggestthat swirling flow vortex core transition phenomena play a very important rolein gas turbine combustors with modern lean-premixed dry low emissions
technology. As the predictability of vortex core transition phenomena has not
yet been investigated sufficiently, a fundamental validation study has been
Turbulent swirling flows, gas turbine combustors,

Study on Flow Fields in Variable Area Nozzles for
Radial Turbines

Study on Flow Fields in Variable Area Nozzles for
Radial Turbines

Study on Flow Fields in Variable Area Nozzles for
Radial Turbines

Hideaki Tamaki, Masaru Unno

Masafumi Miyano, Toshiaki Kanemoto, Daisuke
Kawashima, Akihiro Wada, Takashi Hara, Kazuyuki
SakodaToshifumi Watanabe, Donghyuk Kang, Angelo
Cervone, Yutaka Kawata, Yoshinobu Tsujimoto

Bleeding away a part of the boundary layer next to the wall is an effective
method for controlling boundary-layer distortions from incident shock waves
or curvature in geometry. When the boundary-layer flow is supersonic, thephysics of bleeding with and without an incident shock wave is more
complicated than just the removal of lower momentum fluid next to the wall.
shock-wave/boundary-layer interaction, inlet bleed
This paper reviews CFD studies of shock-wave/boundary-layer interactions ona flat plate with bleed into a plenum through a single hole, three holes intandem, and four rows of staggered holes in which the simulation resolves notjust the flow above the plate, but also the flow through each bleed hole andthe plenum. The focus is on understanding the nature of the bleed process.
EquiMar (Equitable Testing and Evaluation of Marine Energy Extraction Devices
in terms of Performance, Cost and Environmental Impact) is one of the firstround of energy projects under the European Commissions 7th Framework
Programme (FP7). The three year EquiMar project aims to deliver a suite ofprotocols for the evaluation of both wave and tidal converters, harmonizing
testing and evaluation procedures across the wide range of available devices,
accelerating adoption through technology matching and improving the
Ocean Energy Conversion, Renewable Energy,
understanding of both environmental and economic impacts associated with Protocol Development
the deployment of devices. The EquiMar protocols will cover site selection,
initial design, scaling up of designs, the deployment of arrays andenvironmental impact assessment as well as economic issues. EquiMar willbuild on existing protocols, e.g. UK DTI Marine Renewables Development Fund(MRDF) protocols for wave and tidal energy, and engage with international
standards setting activities, e.g. IEC TC114.
Studies on cavitation instabilities of hydrofoils and cascades are reviewed toobtain fundamental understandings of the instabilities observed in turbopump
inducers. Most of them are based on the stability analysis of two-dimensional
inviscid cavitating flow. The most important finding of the analysis is that thecavitation instabilities depend only on the mean cavity length. For a hydrofoil,
Cavitation Instability, Hydrofoil, Cascade, Inducer,
the characteristic length is the chord length and partial/transitional cavity
Rotating Cavitation, Cavitation Surge
oscillation occurs with shorter/longer cavity than 75% of the chord length. For
cascades, the characteristic length is the blade spacing and various modes of
instabilities are predicted when the mean cavity is longer than 65% of thespacing. In the last part, rotating choke is shown to occur when the cavity
becomes longer than the spacing.
The flow behind the variable area nozzle which corresponds to the flow at theleading edge of the impeller was measured with a 3-hole yaw probe andcalculated with CFD. Two nozzle throat-areas were investigated. One is thesmallest and the other is the largest opening for the variable nozzle. Test
Radial turbine, Nozzle vane, Variable geometry
results agreed with the calculated results qualitatively. The leakage flow
turbine, Clearance flow
through the tip clearance of the nozzle vane significantly affected the flow
field downstream of the nozzle vane with the smallest opening. However, theeffect on leakage flow on the flow field downstream of the nozzle vane withthe largest opening was very weak and the effect of wake is dominant.
To optimize the stationary components in the multistage centrifugal pump, theeffects of the return vane profile on the performances of the multistage
centrifugal pump were investigated experimentally, taking account of the inlet
flow conditions for the next stage impeller. The return vane, whose trailingedge is set at the outer wall position of the annular channel downstream ofthe vane and which discharges the swirl-less flow, gives better pump
Return Vane Installed in Multistage Centrifugal Pump
performances. By equipping such return vane with the swirl stop set from thetrailing edge to the main shaft position, the unstable head characteristics canbe also suppressed successfully at the lower discharge. Taking the pump
performances and the flow conditions into account, the impeller blade wasmodified so as to get the shock-free condition where the incidence angle iszero at the inlet.
During an experimental investigation on a 3-bladed and a 4-bladed axial
inducer, a severe surge instability was observed in a range of cavitation
number where the blade passage is choked and the inducer head is decreased
from non-cavitating value. The surge was stronger for the 4-bladed inducer ascompared with a 3-bladed inducer with the same inlet and outlet blade
angles. For the 4-bladed inducer, the head decreases suddenly as thecavitation number is decreased. The surge was observed after the sudden dropof head. This head drop was found to be associated with a rapid extension of Cavitation, instabilities, inducers, surge
tip cavity into the blade passage. The cause of surge is attributed to thedecrease of the negative slope of the head-flow rate performance curve due
to choke. Assuming that the difference between the 3 and 4-bladed inducers
is caused by the difference of the blockage effects of the blade, a test was
carried out by thickening the blades of the 3-bladed inducer. However,
opposite to the expectations, the head drop became smoother and theinstability disappeared on the thickened blade inducer.

OctoberDecember,
2008

In order to extract micro hydropower in the very low specific speed range, aPositive Displacement Turbine (PDT) was proposed and steady performance
was determined experimentally. However, the suppression of large pressure
pulsation is inevitable for practical application of PDT. The objective of the
76-85

Flow Analysis in Positive Displacement Micro-Hydro
Turbine and Development of Low Pulsation Turbine

Junichi Kurokawa, Jun Matsui, Young-Do Choipresent study is to reveal the mechanism and the characteristics of pressure
Micro hydropower, Positive displacement turbine,
pulsation in PDT by use of CFD and to suppress the pressure pulsation.
Helical rotor, Pressure pulsation, Performance
Unsteady CFD analysis has revealed that large pressure pulsation is caused by improvement
large variation of rotational speed of the following rotor, while the driving
rotor, which is output rotor, keeps constant speed. Here is newly proposed a
4-lobe helical type rotor which can reduce the pressure pulsation drasticallyand the performance prediction of new PDT is determined.

86-91

92-100101-108

109-120

Matching Diffuser Vane with Return Vane Installed in

Daisuke Kawashima, Toshiaki Kanemoto, Kazuyuki

Multistage Centrifugal Pump

Sakoda, Akihiro Wada, Takashi Hara

Unsteady Flows Arising in a Mixed-Flow Vaneless
Diffuser System

Hiromu Tsurusaki

Reynolds Number Effect on Regenerative Pump
Performance in Low Reynolds Number Range

Control of Pump Performance with Attaching Flaps
on Blade Trailing Edges

Hironori Horiguchi, Daisuke Yumiba, Yoshinobu
Tsujimoto, Masaaki Sakagami, Shigeo Tanaka

Yuji Kanemori, Ying Kang Pan

The effects of the diffuser vane on the performances of the multistage
centrifugal pump were investigated experimentally, taking account of theinteractions among the diffuser vane, the return vane, and the next stage
Centrifugal pump, diffuser vane, return vane,
impeller. It is very important to match well the diffuser vane with the return
multistage pump, performance, efficiency, hydraulicvane, for improving the hydraulic efficiency of the pump. The efficiency may
loss
be more improved by making the cross-sectional area of the channel from thediffuser vane outlet to the return vane inlet larger, as much as possible.
The main objective of this study was to clarify the origin of the unsteady flows
arising in a mixed-flow vaneless diffuser system and also the effects of physicalcomponents of the system. The testing equipment consists of a straight tube,
a swirl generator, and a mixed-flow vaneless diffuser. Pressure fluctuations of
the flow through the tube and diffuser were measured by using asemiconductor-type pressure transducer and analyzed by an FFT analyzer. In Unsteady flow, Mixed-flow, Vaneless diffuser, Swirlingthe experiment, the velocity ratio (axial velocity/peripheral velocity) of theflow, Pressure fluctuation, Rotating stallinternal flow, and the geometric parameters of the diffuser were varied. Twokinds of unsteady flows were measured according to the combination of thecomponents, and the origin of each unsteady flow was clarified. The
fundamental frequencies of unsteady flows arose were examined by twodimensional small perturbation analysis.
The effect of Reynolds number on the performance of a regenerative pump
was examined in a low Reynolds number range in experiment. The head of theregenerative pump increased at low flow rates and decreased at high flow
rates as the Reynolds number decreased. The computation of the internal flow
was made to clarify the cause of the Reynolds number effect. At low flow
Regenerative Pump, Pump Performance, Reynolds
rates, the head is decreased with increasing the Reynolds number due to the Number Effect, Low Reynolds number
decrease of the shear force exerted by the impeller caused by the increase ofleakage and hence local flow rate. At higher flow rates, the head is increased
with increasing the Reynolds number with decreased loss at the inlet andoutlet as well as the decreased shear stress on the casing wall.
An innovative method of changing a centrifugal low specific speed pump
performance and pressure fluctuation by applying outlet flaps to impeller exithas been investigated. The outlet blade edge section corresponds to thetrailing edge of wing on the circular-cascade, which dominates the pump
performance and pressure fluctuation. Computational fluid dynamics (CFD)
analysis of the entire impeller and volute casing and an experimental
Pump, Flap, Performance, Pressure fluctuation,
investigation are conducted. The pressure fluctuation and the vibration of the Vibration
shaft are measured simultaneously. Kurtosis is applied as a dimensionlessparameter with which the unevenness of velocity distribution at impeller outlet
is indicated. The influence of the flaps on the pressure fluctuation is explainedby the kurtosis. This paper presents a theoretical method of predicting thepump performance related to the attachment of a flap at impeller outlet.

For mechanical drive steam turbines, the investigation results of corrosion
fatigue phenomena in the transient zone are introduced, including basic
phenomena on expansion line and actual design and damage experience.
Investigation of Corrosion Fatigue Phenomena in
These results were analyzed from the standpoint of stress intensity during theTransient Zone and Preventive Coating and Blade
Satoshi Hata, Naoyuki Nagai, Toyoaki Yasui, Hiroshi start of cracking. In order to resolve such problems, preventive coating and121-139
Design against Fouling and Corrosive Environment for
Tsukamotoblade design methods against fouling and corrosive environments are
Mechanical Drive Turbinesdeveloped. Detailed evaluation test results are given for coating performanceusing a unique test procedure simulating fouling phenomena and washingconditions. Finally, the results of the successful modification of internals andon-line washing results on site are introduced.

140-147

148-154

Steam Turbine, Corrosion Fatigue, Wilson Zone,
Thermodynamics, Numerical Analysis, ISB, Surface
Treatment, Hybrid Coating, Deposits, Corrosion,
Erosion, On-line wash

Experimental Study of Check Valves in Pumping
Systems with Air Entrainment

An experiment setup was introduced to study dynamic behaviour of different
types of check valves and the effects of air entrainment on the check valve
performance under pressure transient condition. The experiment results showthat the check valves with low inertia, assisted by springs or small traveling
distance/angle gave better performance under pressure transient condition
than check valves without these features. Air entrainment was found to affectThong See Lee, Hong Tong Low, Dinh Tam Nguyen,
air entrainment, pressure surges, pumping system,
both wave speed and reverse velocity. With the increase of the initial air void
Wei Rong, Avan Neo
check valve
fraction in pipeline, the experiment results show that the wave speed was
reduced, the reverse velocity was increased. The first peak pressure increased
initially and then decreased with the increase of the initial air void fraction, thepressure surge periods were increased proportionally with air void fraction due
to the greatly reduced wave speed. The study can be applied to help choosing
suitable check valves for a particular pumping system.

Influence of Blade Profiles on Flow around Wells
Turbine

The Wells turbine rotor consists of several symmetric airfoil blades arranged
around a central hub, and the stagger angle is 90 degrees. These
characteristics simplify the total construction of OWC type wave energy
converters. Although the Wells turbine is simple, the turbine produces acomplicated flow field due to the peculiar arrangement of blades, which canrotate in the same direction irrespective of the oscillating airflow. In order tounderstand these flows, flow visualization is carried out with an oil-film
method in the water tunnel. This research aims to analyze the mechanism of
the 3-D flows around the turbine with the flow visualization. The flow
visualization explained the influence of attack angle, the difference between
fan-shaped and rectangular wings, and the sweep angle.

Masami Suzuki, Chuichi Arakawa

155-168

Variable Geometry Mixed Flow Turbine for
Turbochargers: An Experimental Study

Srithar Rajoo, Ricardo Martinez-Botas

169-180

Resonance and Instability of Blade-Shaft Coupled
Bending Vibrations with In-plane Blade Vibration

Norihisa Anegawa, Hiroyuki Fujiwara, Akira Okabe,
Osami Matsushita

Page

Title

Author

Wells Turbine, Flow Visualization, Oil Film Method,
Wave Power Generation, Ocean Engineering

This paper investigates a variable geometry (VG) mixed flow turbine with anovel, purposely designed pivoting nozzle vane ring. The nozzle vane ring wasmatched to the 3-dimensional aspect of the mixed flow rotor leading edge
with lean stacking. It was found that for a nozzle vane ring in a volute, thevane surface pressure is highly affected by the flow in the volute rather than
the adjacent vane surface interactions, especially at closer nozzle positions. The
performance of the VG mixed flow turbine has been evaluated experimentallyin steady and unsteady flow conditions. The VG mixed flow turbine showshigher peak efficiency and swallowing capacity at various vane angle settings variable geometry turbocharger, mixed flow turbine,compared to an equivalent nozzleless turbine. Comparison with an equivalent steady flow and pulsating flow
straight vane arrangement shows a higher swallowing capacity but similar
efficiencies. The VG turbine unsteady performance was found to deviate
substantially from the quasi-steady assumption compared to a nozzlelessturbine. This is more evident in the higher vane angle settings (smaller nozzle
passage), where there are high possibility of choking during a pulse cycle. The
presented steady and unsteady results are expected to be beneficial in thedesign of variable geometry turbochargers, especially the ones with a mixed
flow turbine.
As a major component of a power plant, a turbine generator must havesufficient reliability. Longer blades have lower natural frequency, thereby
requiring that the design of the shaft and blade takes into account the
coupling of the blade vibration mode, nodal diameter k =0 and k =1 withvibration of the shaft.
Abstract

Blade-Shaft coupled vibration, Bending vibration,
Resonance, Instability, In-plane vibration, Turbine
generator

Keywords

Surrogate modeling is applied to a compressor blade shape optimization tomodify its stacking line and thickness to enhance adiabatic efficiency and totalpressure ratio. Six design variables are defined by parametric curves and threeobjectives; efficiency, total pressure and a combined objective of efficiency andtotal pressure are considered to enhance the performance of compressor
blade. Latin hypercube sampling of design of experiments is used to generate

1-12Application of Surrogate Modeling to Design of A
Compressor Blade to Optimize Stacking andThickness

Abdus Samad, Kwang-Yong Kim

55 designs within design space constituted by the lower and upper limits ofvariables. Optimum designs are found by formulating a PRESS (predicted error Compressor Blade, Optimization, Surrogate Modeling,
sum of squares) based averaging (PBA) surrogate model with the help of a
Stacking Line, Thickness of Blade, Efficiency
gradient based optimization algorithm. The optimum designs using the current
variables show that, to optimize the performance of turbomachinery blade, theadiabatic efficiency objective is improved substantially while total pressure
ratio objective is increased a very small amount. The multi-objective
optimization shows that the efficiency can be increased with the lesscompensation of total pressure reduction or both objectives can be increased
simultaneously.

13-20

21-30

31-39

40-54

Analysis of Aerodynamic Performance in an AnnularCompressor Bowed Cascade with Large Camber
Angles

Prediction of Wear Depth Distribution by Slurry on a
Pump Impeller

Shaowen Chen, Fu Chen

Kenichi Sugiyama, Hiroshi Nagasaka, Takeshi
Enomoto, Shuji Hattori

61-71

72-79

Slurry wear with sand particles in rivers is a serious problem for pump
operation. Therefore, a technique to predict wear volume loss is required forselecting wear resistant materials and determining specifications for the
maintenance period. This paper reports a method for predicting the wear
Pump, Impeller, Numerical analysis, Slurry wear, Life
depth distribution on the blade of an impeller. Slurry wear tests of an
prediction
aluminum pump impeller were conducted. Prediction results of wear depth
distribution approximately correspond with the results of slurry wear tests. This
technique is useful for industrial application.

A Behavior of the Diffuser Rotating Stall in a Low
Specific Speed Mixed-Flow Pump

The flow instability in a low specific speed mixed-flow pump, having a positive
slope of head-flow characteristics was investigated. Based on the staticpressure measurements, it was found that a rotating stall in the vaned diffuser
occurs at about 65% flow rate of best efficiency point (BEP). A dynamic
Particle Image Velocimetry (DPIV) measurement and the numerical simulations
were conducted in order to investigate the flow fields. As a result, the diffuser
Masahiro Miyabe, Akinori Furukawa, Hideaki Maeda, rotating stall was simulated even by Computational Fluid Dynamics (CFD) and Mixed flow pump, Flow instability, Vaned diffuser,
Isamu Umeki, Yoshinori Jittani
the calculated periodic flow patterns agree well with the measured ones byRotating stall, PIV, CFD
DPIV. It is clarified that a periodical large scaled backflow, generated at theleading edge of the suction surface of the diffuser vane, causes the instability.
Furthermore, the growth of the strong vortex at the leading edge of the
diffuser vane induces the strong backflow from the diffuser outlet to the inlet.
The scale of one stall cell is covered over four-passages in total thirteen vanepassages.

A Backflow Vortex Cavitation and Its Effects on
Cavitation Instabilities

Cavitation instabilities in turbo-machinery such as cavitation surge androtating cavitation are usually explained by the quasi-steady characteristics ofcavitation, mass flow gain factor and cavitation compliance. However, there
are certain cases when it is required to take account of unsteadycharacteristics. As an example of such cases, cavitation surge in industrial
centrifugal pump caused by backflow vortex cavitation is presented and theimportance of the phase delay of backflow vortex cavitation is clarified. First,
fundamental characteristics of backflow vortex structure is shown followed bydetailed discussions on the energy transfer under cavitation surge in thecentrifugal pump. Then, the dynamics of backflow is discussed to explain alarge phase lag observed in the experiments with the centrifugal pump.

Kazuyoshi Yamamoto, Yoshinobu Tsujimoto

Vol 2, No.
1,
JanuaryMarch,
2009

55-60

The effects of positively bowed blade on the aerodynamic performance ofannular compressor cascades with large camber angle were experimentallyinvestigated under different incidences. The distributions of the exit totalpressure loss and secondary flow vectors of compressor cascades wereanalyzed. The static pressure was measured by tapping on the cascadesurfaces, and the ink-trace flow visualizations were conducted. The results
show that the value of the optimum bowed angle and optimum bowed heightdecrease because of the increased losses at the mid-span with the increase of
the caber angle. The C-shape static pressure distribution along the radial
direction exists on the suction surface of the straight cascade with large r
Cascade experiment, compressor, camber angle
camber angles. When bowed blade is applied, the larger bowed angle andlarger bowed height will further enhance the accumulation of the low-energy
fluid at the mid-span, thus deteriorate the flow behavior. Under 60° camber
angle, flow behavior near the end-wall region of some bowed cascades evendeteriorates instead of improving because the blockage of the separated flownear the mid-span keeps the low-energy fluid near the end-walls from moving
towards the mid-span region, and as a result, a rapid augmentation of thetotal loss is easy to take place under large bowed angle. With the increase ofcamber angle, the choice range of bowed angle corresponding to the best
performance in different incidences become narrower.

A Thermal Analysis of a Film Cooling System with
Normal Injection Holes Using Experimental Data

Machine Fault Diagnosis and Prognosis: The State of
The ArtEffect of Internal Flow in Symmetric and Asymmetric
Micro Regenerative Pump Impellers on Their Pressure
Performance

Cavitation, Instability, Backflow, Cavitation Surge,
Inducer, Centrifugal pump, Vortex

Kyung Min Kim, Dong Hyun Lee, Hyung Hee Cho,
Moon Young Kim

The present study investigated temperature and thermal stress distributions ina film cooling system with normal injection cooling flow. 3D-numericalsimulations using the FEM commercial code ANSYS were conducted to
calculate distributions of temperature and thermal stresses. In the simulations,the surface boundary conditions used the surface heat transfer coefficients andadiabatic wall temperature which were converted from the Sherwood numbers
and impermeable wall effectiveness obtained from previous mass transfer
experiments. As a result, the temperature gradients, in contrast to the adiabatic Gas turbine heat transfer, Film cooling, Thermal
wall temperature, were generated by conduction between the hot and cold
analysis, Thermal stress, Finite element method
regions in the film cooling system. The gradient magnitudes were about 10˜
20K in the y-axis (spanwise) direction and about 50˜60K in the x-axis(streamwise) direction. The high thermal stresses resulting from thistemperature distribution appeared in the side regions of holes. These locations
were similar to those of thermal cracks in actual gas turbines. Thus, thisthermal analysis can apply to a thermal design of film cooling holes to preventor reduce thermal stresses.

Tran Van Tung, Bo-Suk Yang

Machine fault diagnostic and prognostic techniques have been theconsiderable subjects of condition-based maintenance system in the recent
time due to the potential advantages that could be gained from reducing
downtime, decreasing maintenance costs, and increasing machine availability.
For the past few years, research on machine fault diagnosis and prognosis has
been developing rapidly. These publications covered in the wide range ofRotating Machinery, Fault Diagnosis, Prognosis
statistical approaches to model-based approaches. With the aim ofsynthesizing and providing the information of these researches for researcher'scommunity, this paper attempts to summarize and classify the recent
published techniques in diagnosis and prognosis of rotating machinery.
Furthermore, it also discusses the opportunities as well as the challenges for
conducting advance research in the field of machine prognosis.

Hironori Horiguchi, Shinji Matsumoto, Yoshinobu
Tsujimoto, Masaaki Sakagami, Shigeo Tanaka

The effect of symmetric and asymmetric micro regenerative pump impellers on
their pressure performance was studied. The shut off head of the pump withthe symmetric impeller was about 2.5 times as that with the asymmetric
impeller. The computation of the internal flow was performed to clarify thecause of the increase of the head. It was found that the contribution of theangular momentum supply was larger than that of shear stress for the head
Regenerative Pump, Pump Performance, Internal Flow,development in both cases. The larger head and momentum supply in the
Leakage Flow, Geometrycase of the symmetric impeller were caused by larger recirculated flow rateand larger angular momentum difference between the inlet and outlet to theimpeller. The larger recirculated flow rate was caused by smaller pressure
gradient in the direction of recirculated flow. The decrease of thecircumferential velocity in the casing was attributed to the smaller local flowrate in the casing.

In this study, a prediction theory for specific noise that is the overallcharacteristic of the fan has been proposed. This theory is based on totalpressure prediction and broadband noise prediction. The specific noises of two
forward curved fans with different number of blades were predicted. The flow

80-91

around the impeller having 120 blades (MF120) was more biased at a certain
positions than the impeller with 40 blades (MF40). An effective domain of theenergy conversion of MF40 has extended overall than MF120. The total
Prediction of Specific Noise Based on Internal Flow ofpressure was affected by the slip factor and pressure loss caused by the vortex Centrifugal Fan, Internal Flow, Wake, Vortex, Pressure
Soichi Sasaki, Hidechito Hayashi, Makoto Hatakeyama
Forward Curved Fan
flow. The suppression of a major pressure drop by the vortex flow andDrop, Aerodynamic Noise
expansion of the effective domain for energy conversion contributed to anincrease in the total pressure of MF40 at the design point. The position of
maximum relative velocity was different for each fan. The relative velocity ofMF120 was less than that of MF40 due to the deviation angle. The specificnoise of MF120 was 2.7 dB less than that of MF40 due to the difference ininternal flow. It has been quantitatively estimated that the deceleration in therelative velocity contributed to the improvement in the overall performance.

92-101

Performance Comparison of Two Wind Turbine
Generator Systems Having Two Types of Control
Methods

Sumio Saito, Satoshi Sekizuka

Page

Title

Author102-109110-120121-126

127-135

Design Optimization of a High Specific Speed Francis
Turbine Using Multi-Objective Genetic Algorithm

Numerical Analysis of the Whole Field Flow in aCentrifugal Fan for Performance Enhancement - The
Effect of Boundary Layer Fences of Different
Configurations

Experimental Study on Internal Flow of a Mini
Centrifugal Pump by PIV Measurement

Study on Design of Air-water Two-phase Flow
Centrifugal Pump Based on Similarity Law

The purpose of this paper is to gain a greater understanding of theperformance of practical wind turbine generating systems with differing output
power controllers and controlling means for wind turbine speed. Subjected
wind turbines, both equipped with an asynchronous power generator, arelocated at two sites and are defined as wind turbine A and wind turbine B inthis study, respectively. Their performance differences are examined byWind turbine, Wind speed, Induction generator,
measuring wind speed and electric parameters. The study suggests that both Asynchronous generator, Power curve, Acoustic noisewind turbines have a clear linkage between current and output powerfluctuations. Comparison of the fluctuations to wind speed fluctuation,although they are triggered primarily by wind speed fluctuation, clearly
indicates the specific behaviors inherent to the respective turbine control
mechanisms.
Abstract

Keywords

Kazuyuki Nakamura, Sadao Kurosawa

A design optimization system for Francis turbine was developed. The system
consists of design program and CFD solver. Flow passage shapes are
optimized automatically by using the system with Multi-Objective Genetic
Algorithm (MOGA). In this study, the system was applied to a high specificFrancis Turbine, Multi-Objective Genetic Algorithm,
speed Francis turbine (nSP = 250m-kW). The runner profile and the draft tube
Optimization Design, Performance
shape were optimized to decrease hydraulic losses. As the results, it was
shown that the turbine efficiency was improved in wide operating range,
furthermore, the height of draft tube was reduced with the hydraulicperformance kept.

K. Vasudeva Karanth, N. Yagnesh Sharma

Generally the fluid flows within the centrifugal impeller passage as adecelerating flow with an adverse pressure gradient along the stream wise
path. This flow tends to be in a state of instability with flow separation zones
on the suction surface and on the front shroud. Hence several experimental
attempts were earlier made to assess the efficacy of using boundary layer
fences to trip the flow in the regions of separation and to make the flow alignitself into stream wise direction so that the losses could be minimized andoverall efficiency of the diffusion process in the fan could be increased. With
the development of CFD, an extensive numerical whole field analysis of theeffect of boundary layer fences in discrete regions of suspected separation
Boundary layer fence, Flow separation, Sliding mesh,points is possible. But it is found from the literature that there have been no Unsteady analysis, Recirculation zone, Jets and wakes
significant attempts to use this tool to explore numerically the utility of thefences on the flow field. This paper attempts to explore the effect of boundary
layer fences corresponding to various geometrical configurations on the
impeller as well as on the diffuser. It is shown from the analysis that the fences
located on the impellers near the trailing edge on pressure side and suction
side improves the static pressure recovery across the fan. Fences provided at
the radial mid-span on the pressure side of the diffuser vane and near theleading edge and trailing edge of the suction side of diffuser vanes also
improve the static pressure recovery across the fan.

Yulin Wu, Huijing Yuan, Jie Shao, Shuhong Liu

The internal flow field in a centrifugal pump working at the several flow
conditions has been measured by using the particle image velocimetry (PIV)
technique with the laser induced fluorescence (LIF) particles and the refractive
index matched (RIM) facilities. The impeller of the centrifugal pump has anCentrifugal pump, PIV, laser induced fluorescence,outlet diameter in 100mm, and consists of six two-dimensional curvaturerefractive index matchedbackward swept blades of constant thickness. Measured results give reliableflow patterns in the pump. It is obvious that application of LIF particle and
RIM are the key methods to obtain the right PIV measured results in pumpinternal flow.

Naoki Matsushita, Akinori Furukawa, Satoshi
Watanabe, Kusuo Okuma

A conventional centrifugal pump causes a drastic deterioration of air-water
two-phase flow performances even at an air-water two-phase flow conditionof inlet void fraction less than 10% in the range of relatively low water flow
rate. Then we have developed a two-phase flow centrifugal pump which
consists of a tandem arrangement of double rotating cascades and blades ofouter cascade have higher outlet angle more than 90°. In design of the twophase flow pump for various sized and operating conditions, similarity
Centrifugal pump, Air-water two-phase flow, Pump
relations of geometric dimensions to hydraulic performances is very useful. The performance, Similarity law
similarity relations of rotational speed, impeller diameter and blade height areinvestigated for the developed impeller in the present paper. As the results,
the similarity law of rotational speed and impeller diameter is clarified
experimentally even in two-phase flow condition. In addition, influences of
blade height on air-water two-phase flow performances indicate a little
difference from the similarity relations.

Small axial fans have become widely used as cooling devices in recent years.
Because of their increasing importance, studies have been conducted on ways
to improve the performance and reduce the noise of such fans. In this report,a small axial fan with a diameter of 85 mm (a type popularity used in personal
computer or workstation) was selected for further examination. The influence
Experimental Research for Performance and Noise of136-146
Takahiro Ito, Gaku Minorikawa, Qinyin Fan
on aerodynamic performance and noise of such frame design parameters as
Axial Flow Fan, Performance, Efficiency, Noise, Frame
Small Axial Fan
blade tip clearance results in a decrease of discrete frequency noise and anincrease of broad-spectrum noise. As for the most suitable design refinementin terms of fan efficiency, we found that the treatment of outlet cornerroundness and altering spoke skew to the direction counter to that of fan
Vol. 2, No.
rotation was effective.
2, AprilDynamic characteristics of the clearance flow between an axially oscillating
June, 2009
rotational disk and a stationary disk were examined by experiments andcomputations based on a bulk flow model. In the case without pressure
fluctuations at the inlet and outlet of the clearance, parallel and contracting
flow paths had an effect to stabilize the axial oscillation of the rotating disk.
Dynamic Characteristics of the Radial Clearance Flow
The enlarged flow path had an effect to destabilize the axial oscillation due toHironori Horiguchi, Yoshinori Ueno, Koutaro
Pump, Flow Induced Vibration, Axisymmetric Flow,
147-155
between Axially Oscillating Rotational Disk andthe negative damping and stiffness for outward and inward flows, respectively.
Takahashi, Kazuyoshi Miyagawa, Yoshinobu Tsujimoto
Clearance Flow, Balance Disk, Bulk Flow Model
Stationary Disk
It was shown that the fluid force can be decomposed into the component
caused by the inlet or outlet pressure fluctuation without the axial oscillationand that due to the axial oscillation without the inlet or outlet pressure
fluctuation. A method to predict the stiffness and damping coefficients is
proposed for general cases when the device is combined with an arbitrary flow
system.
This paper aims to describe the importance of data, data collection methods,
parameters to estimate the potential of wave energy and environmental
A Review of Ocean Wave Power Extraction; theW. B. Wan Nik, A. M. Muzathik, K. B. Samo, M. Z.
impacts. The technical and economical status in wave energy conversion is
Wave energy, Wave parameters, Wave data sources,156-164
primary interface
Ibrahimoutlined. Power and energy efficiency relationships are discussed. Many
Energy conversion, Environmental impact
different types of wave-energy converters have been detailed. The progress inwave energy conversion in Malaysia is reviewed.

We developed a 'multi-point vibration acceleration method' for accurately
predicting the cavitation intensity in pumps. Pressure wave generated bycavitation bubble collapse propagates and causes pump vibration. We
measured vibration accelerations at several points on a casing, suction anddischarge pipes of centrifugal and mixed-flow pumps. The measured vibration
accelerations scattered because the pressure wave damped differently between
the bubble collapse location and each sensor. In a conventional method,experimental constants are proposed without evaluating pressure propagation

Prediction of Cavitation Intensity in Pumps Based on
Propagation Analysis of Bubble Collapse Pressure
Using Multi-Point Vibration Acceleration Method

paths, then, the scattered vibration accelerations cause the inaccurate
cavitation intensity. In our method, we formulated damping rate, transmittanceof the pressure wave, and energy conversion from the pressure wave to thevibration along assumed pressure propagation paths. In the formulation, we

Cavitation intensity, Bubble collapse, Pressure
theoretically defined a 'pressure propagation coefficient,' which is a correlation
propagation, Vibration acceleration, Pump
coefficient between the vibration acceleration and the bubble collapsepressure. With the pressure propagation coefficient, we can predict thecavitation intensity without experimental constants as proposed in aconventional method. The prediction accuracy of cavitation intensity isimproved based on a statistical analysis of the multi-point vibration
accelerations. The predicted cavitation intensity was verified with the plastic
deformation rate of an aluminum sheet in the cavitation erosion area of theimpeller blade. The cavitation intensities were proportional to the measured
plastic deformation rates for three kinds of pumps. This suggests that our
method is effective for estimating the cavitation intensity in pumps. We canmake a cavitation intensity map by conducting this method and varying theflow rate and the net positive suction head (NPSH ). The map is useful for avoiding theThis paper reports on an investigation (using RSM with commercial CFD
software) of the performance characteristics of the impeller in a centrifugal
pump. Geometric parameters of vane plane development were defined withthe meridional shape and frontal view of the impeller. The parameters arefocused on the blade-angle distributions through the impeller in a fixed
Design Optimization of Centrifugal Pump Impellers in Sung Kim, Young-Seok Choi, Kyoung-Yong Lee, JoonCentrifugal pump, Impeller, Optimization,
172-178
meridional geometry. For screening, a 2k factorial design has been used toa Fixed Meridional Geometry using DOEYong Yoon
RSM(Response surface method)
identify the important design parameters. The objective functions are definedas the total head rise and the total efficiency at the design flow-rate. From the
2k factorial design results, it is found that the incidence angles and the exit
blade angle are the most important parameters influencing the performance ofthe pump.
165-171

Masashi Fukaya, Shigeyoshi Ono, Ryujiro Udo

179-188

Surrogate Based Optimization Techniques for
Aerodynamic Design of Turbomachinery

Abdus Samad, Kwang-Yong Kim

Page

Title

Author

189-196197-205

Study for the Increase of Micro Regenerative Pump
Head

Fluid-Oscillation Coupled Analysis for HAWT Rotor
Blade (One Degree of Freedom Weak Coupling
Analysis with Hinge-Spring Model)

Hironori Horiguchi, Keisuke Wakiya, Yoshinobu
Tsujimoto, Masaaki Sakagami, Shigeo Tanaka

Recent development of high speed computers and use of optimization
techniques have given a big momentum of turbomachinery design replacing
expensive experimental cost as well as trial and error approaches. The
surrogate based optimization techniques being used for aerodynamic
turbomachinery designs coupled with Reynolds-averaged Navier-Stokes
equations analysis involve single- and multi-objective optimization methods.
The objectives commonly tried to improve were adiabatic efficiency, pressure
ratio, weight etc. Presently coupling the fluid flow and structural analysis isbeing tried to find better design in terms of weight, flutter and vibration, andturbine life. The present article reviews the surrogate based optimization
techniques used recently in turbomachinery shape optimizations.

Turbomachinery, surrogate modeling, optimization,
Pareto optimal front, CFD

Abstract

Keywords

The effect of inlet and outlet blade angles on a micro regenerative pump head
was examined in experiments. The pump head was little increased by changing
the blade angles compared with the original pump with the inlet and outlet
blade angles of 0 degree. The effect of the axial clearance between the
impeller and the casing on the pump head was also examined. The head wasincreased largely by decreasing the axial clearance. The computation of theinternal flow was performed to clarify the cause of the increase of the pump
Micro Regenerative Pump, Internal Flow, Blade Angle,
head due to the decrease of the clearance. The local flow rate in the casing
Clearance, Leakage Flowdecreased as the leakage flow rate through the axial clearance decreased dueto the decrease of the clearance. It was found that the larger head in thesmaller clearance was just caused by the smaller local flow rate in the casing.
In the case of the smaller clearance, the smaller local flow rate caused thesmaller circumferential velocity near the front and rear sides of the impeller.
This caused the increase of the angular momentum in the casing and thehead.

Since large-scale commercial wind turbine generator systems such as MWclass wind turbines are becoming widely operated, the vibration and distortionof the blade are becoming larger and larger. Therefore the soft structure
design instead of the solid-design is one of the important concepts to reduce
the structural load and the cost of the wind turbine rotors. The objectives ofthe study are development of the fluid-structure coupled analysis code andevaluation of soft rotor-blade design to reduce the unsteady structural blade
Hiroshi Imamura, Yutaka Hasegawa, Junsuke Murata,
Wind Turbine, Free Wake Panel Method, Weakload. In this paper, fluid-structure coupled analysis for the HAWT rotor blade is
Sho Chihara, Daisuke Takezaki, Naotsugu Kamiya
Coupling Analysis, Hinge-Spring Model, Yawed Inflow
performed by free wake panel method coupled with hinge-spring blade modelfor the flapwise blade motion. In the model, the continuous deflection of therotor blade is represented by flapping angle of the hinge with one degree of
freedom. The calculation results are evaluated by comparison with the
database of the NREL unsteady aerodynamic experiment. In the analysis theunsteady flapwise moments in yawed inflow conditions are compared for theblades with different flapwise eigen frequencies.

Alternate blade cavitation, rotating cavitation and cavitation surge in rocket
turbopump inducers were simulated by a three dimensional commercial CFD
code. In order to clarify the cause of cavitation instabilities, the velocity
disturbance caused by cavitation was obtained by subtracting the velocity
vector under non-cavitating condition from that under cavitating condition. It
Cause of Cavitation Instabilities in Three Dimensional Donghyuk Kang, Koichi Yonezawa, Hironori Horiguchi,
Inducer, Cavitation instabilities, Velocity disturbance,
206-214
was found that there exists a disturbance flow towards the trailing edge of theInducer
Yutaka Kawata, Yoshinobu Tsujimoto
Three dimensional CFD
tip cavity. This flow has an axial flow component towards downstream which
reduces the incidence angle to the next blade. It was found that all of thecavitation instabilities start to occur when this flow starts to interact with theleading edge of the next blade. The existence of the disturbance flow was
validated by experiments.

215-222Vol. 2,
No.3, JulySeptember, 2009Flow Field Change before Onset of Flow Separation

Hiroaki Hasegawa, Takeru Sugawara

Jets issuing through small holes in a wall into a freestream has proveneffective in the control of flow separation. This technique is known as thevortex generator jet (VGJs) method. If a precursor signal of separation isfound, the separation control system using VGJs can be operated just before
the onset of separation and the flow field with no separation is always
attained. In this study, we measured the flow field and the wall static pressure
in a two-dimensional diffuser to find a precursor signal of flow separation. The
Separation, Boundary Layer, Unsteady Flow, Diffuser,
streamwise velocity measurements were carried out in the separated shear
Precursor
layer and spectral analysis was applied to the velocity fluctuations at someangles with respect to the diffuser. The pattern of peaks in the spectral
analysis changes as the divergence angle increases over the angle of which thewhole separation occurs. This change in the spectral pattern is related to theenhancement of the growth of shear layer vortices and appears just before theonset of separation. Therefore, the growth of shear layer vortices can be
regarded as a precursor signal to flow separation.

Vol. 2,
No.3, JulySeptember, 2009Experimental investigations were conducted for the internal flows of the axial
flow stator and diagonal flow rotor. Corner separation near the hub surface
and the suction surface of stator blade are mainly focused on. For the design
flow rate, the values of the axial velocity and the total pressure at stator outlet
223-231

Experimental Investigation on Separated Flows of

Yoichi Kinoue, Norimasa Shiomi, Toshiaki Setoguchi,

Axial Flow Stator and Diagonal Flow Rotor

Yingzi Jin

decrease between near the suction surface and near the hub surface by the
Axial flow stator, Diagonal flow rotor, Internal flow,
influence of corner wall. For the flow rate of 80-90% of the design flow rate,
Corner separation
the corner separation of the stator between the suction surface and the hub
surface is observed, which becomes widely spread for 80% of the design flow
rate. At rotor outlet for 81% of the design flow rate, the low axial velocity
region grows between near the suction surface of rotor and the casing surface
because of the tip leakage flow of the rotor.

Toshifumi Watanabe, Hideyoshi Sato, Yasuhiko232-238239-247

Unlike usual turbopump inducers, the axial flow pump tested operates very
stably at design flow rate without rotating cavitation nor cavitation surge. Flowvisualization suggests that this is because the tip cavity smoothly extends into

Rotating Choke and Choked Surge in an Axial Pump
Pump, Cavitation, Cavitation Instability, Rotating
Henmi, Hironori Horiguchi, Yutaka Kawata, Yoshinobu
the flow passage without the interaction with the leading edge of the next
Impeller
Choke, Choked Surge
Tsujimotoblade. However, at low flow rate and low cavitation number, choked surge androtating choke were observed. Their correlation with the performance curveunder cavitation is discussed and their instantaneous flow fields are shown.

A Study of Performance and Internal Flow in a New
Type of Sewage Pump

Yasuyuki Nishi, Junichiro Fukutomi

Sewage pumps are designed with a wide flow channel by, for example,
sacrificing some efficiency and reducing the number of blades, in order toprevent plugging with foreign bodies. However, the behavior of foreign bodies
which actually flow into a pump is extremely complex, and there are questions
about whether the presumed foreign bodies will actually pass through. This
paper proposes a new type of sewage pump impeller designed to further
improve pump efficiency and performance in passing foreign bodies. This
Turbomachinery, Sewage Pump, Single Blade,sewage pump impeller has a structure in which the suction flow channel of a Performance, Internal Flowclosed type non-clog pump is wound in a helical spiral. The focus of thisresearch was to investigate pump performance and internal flow in this single
blade sewage pump impeller. The results clearly indicated the following facts:
The developed sewage pump impeller exhibits high efficiency over a wide
range of flow rates; internal flow of the pump is very complicated; and theinternal flow state varies greatly when the flow rate changes.
This paper presents a numerical study for unsteady flows in a high-pressure
steam turbine with a partial admission stage. Compressible Navier-Stokes
equations are solved by the high-order high-resolution finite-difference
method based on the fourth-order compact MUSCL TVD scheme, Roe's
approximate Riemann solver, and the LU-SGS scheme. The SST-model is also
solved for evaluating the eddy-viscosity. The unsteady two-dimensional flows Numerical Study, Steam Turbine, Unsteady Flow,through whole nozzle-rotor cascade channels considering a partial admission Partial Admission, Nozzle-rotor Cascade Channels
are numerically investigated. 108 nozzle passages with two blockages and 60
rotor passages are simultaneously calculated. The influence of the flange in thenozzle box to the lift of rotors is predicted. Also the efficiency of the partial
admission stage changing the number of blockages and the number ofnozzles is parametrically predicted.

Numerical Prediction of Unsteady Flows throughWhole Nozzle-Rotor Cascade Channels with Partial
Admission

Yasuhiro Sasao, Kazuhiro Monma, Tadashi Tanuma,
Satoru Yamamoto254-259

Vibration Analysis of a Rotor considering Nonlinear
Reaction of Hydrodynamic Bearing

In this paper it was attempted to treat the hydrodynamic journal bearing as atime-based nonlinear reaction source in each step of rotor rotation in order toobserve the bearing effect more realistically and accurately in stead of theconventional method of simple linearized stiffness and damping. Lubrication Rotating Machinery, Lateral Vibration Analysis, Journal
Soo-Mok Lee, Do-Hyeong Lim, Jong-Gug Bae, Bo-Suk
analysis based on finite element method is employed to calculate the
Bearing, Nonlinear Hydrodynamic Reaction,Yanghydrodynamic reaction of bearing and Newmark's method was used toUnbalance Response Analysis, Electric Motor
calculate the rotor dynamics in the time domain. Simulation for an industrial
electrical motor showed remarkable results with differences compared to thoseby the conventional method in the dynamic behavior of the rotor.

260-268

One-Dimensional Analysis of Full Load Draft Tube
Surge Considering the Finite Sound Velocity in the
Penstock

The effects of acoustic modes in the penstock on the self-excited oscillation in
hydraulic power system were studied by assuming a finite sound velocity in
Changkun Chen, Christophe Nicolet, Koichi Yonezawa, the penstock. The flow in the draft tube is considered to be incompressible
Draft tube surge, finite sound velocity, higher order
Mohamed Farhat, Francois Avellan, Yoshinobu
assuming that the length of the draft tube is smaller than the wavelength of
frequencies
Tsujimotothe oscillation. It was found that various acoustic modes in the penstock can
become unstable (amplified) by the diffuser effect of the draft tube or theeffect of swirl flow from the runner. Their effects on each mode are discussed.

Page

Title

248-253269-277278-285

Unsteady Flow with Cavitation in Viscoelastic Pipes

Uncertainty in Operational Modal Analysis of
Hydraulic Turbine Components

Author

Abstract

Keywords

Alexandre K. Soares, Dídia I.C. Covas, Helena M.
Ramos, Luisa Fernanda R. Reis

The current paper focuses on the analysis of transient cavitating flow inpressurised polyethylene pipes, which are characterized by viscoelastic
rheological behaviour. A hydraulic transient solver that describes fluid
transients in plastic pipes has been developed. This solver incorporates thedescription of dynamic effects related to the energy dissipation (unsteady
friction), the rheological mechanical behaviour of the viscoelastic pipe and thecavitating pipe flow. The Discrete Vapour Cavity Model (DVCM) and the
Discrete Gas Cavity Model (DGCM) have been used to describe transient
cavitating flow. Such models assume that discrete air cavities are formed in
fixed sections of the pipeline and consider a constant wave speed in pipe
reaches between these cavities. The cavity dimension (and pressure) is allowed
to grow and collapse according to the mass conservation principle. An
Cavitating flow, Fluid transients, Viscoelasticity,
extensive experimental programme has been carried out in an experimental
Pipelines, Experimental data
set-up composed of high-density polyethylene (HDPE) pipes, assembled at
Instituto Superior Técnico of Lisbon, Portugal. The experimental facility iscomposed of a single pipeline with a total length of 203 m and inner diameterof 44 mm. The creep function of HDPE pipes was determined by using an
inverse model based on transient pressure data collected during experimental
runs without cavitating flow. Transient tests were carried out by the fastclosure of the ball valves located at downstream end of the pipeline for the
non-cavitating flow and at upstream for the cavitating flow. Once therheological behaviour of HDPE pipes were known, computational simulations
have been run in order to describe the hydraulic behaviour of the system forthe cavitating pipe flow. The calibrated transient solver is capable of accurately
describing the attenuation, dispersion and shape of observed transientMartin Gagnon, S.-Antoine Tahan, André Coutu

Operational modal analysis (OMA) allows modal parameters, such as natural
frequencies and damping, to be estimated solely from data collected during
operation. However, a main shortcoming of these methods resides in theevaluation of the accuracy of the results. This paper will explore theuncertainty and possible variations in the estimates of modal parameters fordifferent operating conditions. Two algorithms based on the Least Square
Flow induced vibration, modal analysis, system
Complex Exponential (LSCE) method will be used to estimate the modal
identification, uncertainty, modal parametersparameters. The uncertainties will be calculated using a Monte-Carlo approachwith the hypothesis of constant modal parameters at a given operating
condition. In collaboration with Andritz-Hydro Ltd, data collected on two
different stay vanes from an Andritz-Hydro Ltd Francis turbine will be used.
This paper will present an overview of the procedure and the results obtained.

Hydroelectric power plants are known for their ability to cover variations of
the consumption in electrical power networks. In order to follow this changing
demand, hydraulic machines are subject to off-design operation. In that case,the swirling flow leaving the runner of a Francis turbine may act under given
conditions as an excitation source for the whole hydraulic system. In high load
operating conditions, vortex rope behaves as an internal energy source whichleads to the self excitation of the system. The aim of this paper is to identify
the influence of the full load excitation source location with respect to theeigenmodes shapes on the system stability. For this, a new eigenanalysis tool,
Influence of the Francis Turbine location under vortex S. Alligné, C. Nicolet, P. Allenbach, B. Kawkabani, J.-J.
Instability, Vortex rope, Eigenvalues, Viscoelastic
286-294
based on eigenvalues and eigenvectors computation of the nonlinear set ofrope excitation on the Hydraulic System Stability
Simond, F. Avellan
damping, Francis Turbine
differential equations in SIMSEN, has been developed. First the modal analysis
method and linearization of the set of the nonlinear differential equations are
fully described. Then, nonlinear hydro-acoustic models of hydrauliccomponents based on electrical equivalent schemes are presented andlinearized. Finally, a hydro-acoustic SIMSEN model of a simple hydraulic power
plant, is used to apply the modal analysis and to show the influence of theturbine location on system stability. Through this case study, it brings out thatmodeling of the pipe viscoelastic damping is decisive to find out stability limits
and unstable eigenfrequencies.

295-302303-314315-323

Axisymmetric Swirling Flow Simulation of the Draft
Tube Vortex in Francis Turbines at Partial Discharge

Dynamic Analysis of Francis Runners - Experimentand Numerical Simulation

Overload Surge Investigation Using CFD Data

Unstable Operation of Francis Pump-Turbine at
324-333 Runaway: Rigid and Elastic Water Column Oscillation
Modes

The flow in the draft tube cone of Francis turbines operated at partial
discharge is a complex hydrodynamic phenomenon where an incoming steadyaxisymmetric swirling flow evolves into a three-dimensional unsteady flow fieldwith precessing helical vortex (also called vortex rope) and associated pressure
fluctuations. The paper addresses the following fundamental question: is it
possible to compute the circumferentially averaged flow field induced by theprecessing vortex rope by using an axisymmetric turbulent swirling flow
model? In other words, instead of averaging the measured or computed 3D
velocity and pressure fields we would like to solve directly the circumferentiallyaveraged governing equations. As a result, one could use a 2D axi-symmetricmodel instead of the full 3D flow simulation, with huge savings in both
Romeo Susan-Resiga, Sebastian Muntean, Peter Stein,computing time and resources. In order to answer this question we firstdraft tube, vortex rope, turbulent axisymmetric flow,
François Avellan
compute the axisymmetric turbulent swirling flow using available solvers by stagnant region model
introducing a stagnant region model (SRM), essentially enforcing aunidirectional circumferentially averaged meridian flow as suggested by theexperimental data. Numerical results obtained with both models are comparedagainst measured axial and circumferential velocity profiles, as well as for thevortex rope location. Although the circumferentially averaged flow field cannot
capture the unsteadiness of the 3D flow, it can be reliably used for further
stability analysis, as well as for assessing and optimizing various techniques tostabilize the swirling flow. In particular, the methodology presented andvalidated in this paper is particularly useful in optimizing the blade design inorder to reduce the stagnant region extent, thus mitigating the vortex ropeand expending the operating range for Francis turbines.

Stefan Lais, Quanwei Liang, Urs Henggeler, Thomas
Weiss, Xavier Escaler, Eduard Egusquiza

The present paper shows the results of numerical and experimental modal
analyses of Francis runners, which were executed in air and in still water. In its
first part this paper is focused on the numerical prediction of the model
parameters by means of FEM and the validation of the FEM method.
Influences of different geometries on modal parameters and frequency
reduction ratio (FRR), which is the ratio of the natural frequencies in water andthe corresponding natural frequencies in air, are investigated for two different
runners, one prototype and one model runner. The results of the analyses
indicate very good agreement between experiment and simulation. Particularly
Modal analysis, fluid structure interaction, rotor-stator
the frequency reduction ratios derived from simulation are found to agree very
interaction, harmonic response analysis, instationary
well with the values derived from experiment. In order to identify sensitivity of
CFD
the structural properties several parameters such as material properties,
different model scale and different hub geometries are numericallyinvestigated. In its second part, a harmonic response analysis is shown for aFrancis runner by applying the time dependent pressure distribution resulting
from an unsteady CFD simulation to the mechanical structure. Thus, the data
gained by modern CFD simulation are being fully utilized for the structuraldesign based on life time analysis. With this new approach a more precise
prediction of turbine loading and its effect on turbine life cycle is possible
allowing better turbine designs to be developed.

Felix Flemming, Jason Foust, Jiri Koutnik, Richard K.
FisherPressure oscillations triggered by the unstable interaction of dynamic flow
features of the hydraulic turbine with the hydraulic plant system - including
the electrical design - can at times reach significant levels and could lead todamage of plant components or could reduce component lifetime
significantly. Such a problem can arise for overload as well as for part load
operation of the turbine. This paper discusses an approach to analyze theoverload high pressure oscillation problem using computational fluid dynamic(CFD) modeling of the hydraulic machine combined with a network modeling
Overload Surge, CFD, System Analysis, Cavitation,technique of the hydraulic system. The key factor in this analysis is the
Vortex Rope, Francis Turbine
determination of the overload vortex rope volume occurring within the turbine
under the runner which is acting as an active element in the system. Two
different modeling techniques to compute the flow field downstream of therunner will be presented in this paper. As a first approach, single phase flow
simulations are used to evaluate the vortex rope volume before moving tomore sophisticated modeling which incorporates two phase flow calculations
employing cavitation modeling. The influence of these different modelingstrategies on the simulated plant behavior will be discussed.

Christophe Nicolet, Sébastien Alligné, Basile
Kawkabani, Jean-Jacques Simond, François AvellanThis paper presents a numerical simulation study of the transient behavior of a
2x340MW pump-turbine power plant, where the results show an unstablebehavior at runaway. First, the modeling of hydraulic components based onequivalent schemes is presented. Then, the 2 pump-turbine test case ispresented. The transient behavior of the power plant is simulated for a case of
emergency shutdown with servomotor failure on Unit 1. Unstable operation at
runaway with a period of 15 seconds is properly simulated using a 1Transient behavior, runaway, instabilities, oscillation
dimensional approach. The simulation results points out a switch after 200
modes
seconds of the unstable behavior between a period of oscillations initially of
15 seconds to a period of oscillation of 2.16 seconds corresponding to thehydraulic circuit first natural period. The pressure fluctuations related to both
the rigid and elastic water column mode are presented for oscillation modecharacterization. This phenomenon is described as a switch between a rigid
and an elastic water column oscillation mode. The influence of the rotating
inertia on the switch phenomenon is investigated through a parametric study.

Pumped storage power plants are playing a significant role in the contribution
to the stabilization of an electrical grid, above all by stable operation and fast
reaction to sudden load respectively frequency changes. Optimized efficiency
and smooth running characteristics both in pump and turbine operation,

Dynamic Simulation of Pump-Storage Power Plants
334-345 with different variable speed configurations using theSimsen Tool

Klaus Krüger, Jiri Koutnik

improved stability for synchronization in turbine mode, load control in pumpmode operation and also short reaction times may be achieved using
adjustable speed power units. Such variable speed power plants are applicablefor high variations of head (e.g. important for low head pump-turbine
projects). Due to the rapid development of power semiconductors andfrequency converter technology, feasible solutions can be provided even for pumped storage, pump-turbine, variable speed,large hydro power units. Suitable control strategies as well as clear design dynamic simulation, optimization, power converters
criteria contribute significantly to the optimal usage of the pump turbine andmotor-generators. The SIMSEN tool for dynamic simulations has been used forcomparative investigations of different configurations regarding the power
converter topology, types of semiconductors and types of motor-generators
including the coupling to the hydraulic system. A brief overview of theadvantages & disadvantages of the different solutions can also be found in
this paper. Using this approach, a customized solution minimizing cost andexploiting the maximum usage of the pump-turbine unit can be developed in
the planning stage of new and modernization pump storage projects.

346-352

Large Eddy Simulation of a High Reynolds Number
Swirling Flow in a Conical Diffuser

Cédric Duprat, Olivier Métais, Thomas Laverne

The objective of the present work is to improve numerical predictions of
unsteady turbulent swirling flows in the draft tubes of hydraulic power plants.
We present Large Eddy Simulation (LES) results on a simplified draft tube
consisting of a straight conical diffuser. The basis of LES is to solve the large
scales of motion, which contain most of the energy, while the small scales aremodeled. LES strategy is here preferred to the average equations strategies(RANS models) because it resolves directly the most energetic part of theLarge-Eddy Simulation, Near-wall scaling, Swirling
turbulent flow. LES is now recognized as a powerful tool to simulate realapplications in several engineering fields which are more and more frequently flows, CFD
found. However, the cost of large-eddy simulations of wall bounded flows is
still expensive. Bypass methods are investigated to perform high-Reynoldsnumber LES at a reasonable cost. In this study, computations at a Reynolds
number about 2 105 are presented. This study presents the result of a new near-wall model for
turbulent boundary layer taking into account the streamwise pressure gradient (adverse or favorable).
Validations are made based on simple channel flow, without any pressure gradient and on the database ERCOFTAC. The experiments carried out by Clausen et al. [1] reproduce the essential featuresof the complex flow and are used to develop and test closure models for such flows.

Vol. 2, No.
4,
OctoberDecember,
2009353-362

Surface Roughness Impact on Francis Turbine
Performances and Prediction of Efficiency Step Up

Pierre Maruzewski, Vlad Hasmatuchi, Henri-Pascal
Mombelli, Danny Burggraeve, Jacob Iosfin, Peter
Finnegan, François Avellan363-374

Study of Stay Vanes Vortex-Induced Vibrations withdifferent Trailing-Edge Profiles Using CFD

Alexandre D'Agostini Neto, Fábio Saltara

In the process of turbine modernizations, the investigation of the influences ofwater passage roughness on radial flow machine performance is crucial andvalidates the efficiency step up between reduced scale model and prototype.
This study presents the specific losses per component of a Francis turbine,which are estimated by CFD simulation. Simulations are performed for different
water passage surface roughness heights, which represents the equivalentsand grain roughness height. As a result, the boundary layer logarithmic
velocity profile still exists for rough walls, but moves closer to the wall.
Consequently, the wall friction depends not only on roughness height but also
on its shape and distribution. The specific losses are determined by CFD
numerical simulations for each component of the prototype, taking into
account its own specific sand grain roughness height. The model efficiency
Francis Turbine, Model and Prototype Testing, CFD
step up between reduced scale model and prototype value is finally computed
Simulation, Efficiency Step Up
by the assessment of specific losses on prototype and by evaluating specificlosses for a reduced scale model with smooth walls. Furthermore, surveys ofrough walls of each component were performed during the geometry recovery
on the prototype and comparisons are made with experimental data from the
EPFL Laboratory for Hydraulic Machines reduced scale model measurements.
This study underlines that if rough walls are considered, the CFD approach
estimates well the local friction loss coefficient. It is clear that by considering
sand grain roughness heights in CFD simulations, its forms a significant part of
the global performance estimation. The availability of the efficiency fieldmeasurements provides an unique opportunity to assess the CFD method inview of a systematic approach for turbine modernization step up evaluation.
Moreover, this paper states that CFD is a very promising tool for future
The 2D flow around 13 similar stay-vane profiles with different trailing edge
geometries is investigated to determinate the main characteristics of theexcitation forces for each one of them and their respective dynamic behaviors
when modeled as a free-oscillating system. The main goal is avoid problems
with cracks of hydraulic turbines components. A stay vane profile with ahistory of cracks was selected as the basis for this work. The commercial finitevolume code FLUENT® was employed in the simulations of the stationary
profiles and, then, modified to take into account the transversal motion ofelastically mounted profiles with equivalent structural stiffness and damping.
The k-ω SST turbulence model is employed in all simulations and a deforming
Vortex-Induced Vibrations, Stay Vanes, Trailing-Edgemesh technique used for models with profile motion. The static-model
Profilesimulations were carried out for each one of the 13 geometries using a
constant far field flow velocity value in order to determine the lift force
oscillating frequency and amplitude as a function of the geometry. The freeoscillating stay-vane simulations were run with a low mass-damping parameter(m*ζ=0.0072) and a single mean flow velocity value (5m/s). The structural
bending stiffness of the stay-vane is defined by the Reduced Velocity
parameter (Vr). The dynamic analyses were divided into two sets. The first setof simulations was carried out only for one profile with 2≤Vr≤12. The second
set of simulations focused on determining the behavior of each one of the 13
profiles in resonance.

Hydraulic instability associated with pressure fluctuations is a serious problem
in hydraulic machinery. Pressure fluctuations are usually a result of a strong
vortex created in the centre of a flow at the outlet of a runner. At every radial
turbine and also at every single regulating axial turbine, the draft tube vortex
appears at part-load operating regimes. The consequences of the vortex
developed in the draft tube are very unpleasant pressure pulsation, axial andradial forces and torque fluctuation as well as turbine structure vibration. The
Numerical prediction of pressure pulsation amplitudeconsequences of the vortex are transferred upstream and downstream with
375-382
for different operating regimes of Francis turbine
Andrej Lipej, Dragica Jošt, Peter Meznar, Vesko Djelic
radial turbine, vortex, pressure pulsation
amplitude and frequency modulation in respect of the turbine operating
draft tubes
regime, cavitation conditions and air admitted content. Numerical predictionof the vortex appearance in the design stage is a very important task. The
amplitude of the pressure pulsation is different for each operating regime
therefore the main goal of this research was to numerically predict pressure
pulsation amplitude versus different guide vane openings and to compare theresults with experimental ones. For the numerical flow analysis of a complete
Francis turbine (FT), the computer code ANSYS-CFX11 has been used.
Vibrations at different frequencies with a different intensity as well as apressure pulsation with different parameters are two phenomena which can beobserved at different water turbines. Due to the vibration and the pressure
pulsation some restrictions of water turbine operation range are applied.
Similar problems with the efficiency level in a wide water turbine operation
range are the basic problems which are solved for ages. A theoretical and
A New Concept of Hydraulic Design of Water Turbine Jindrich Vesely, Frantisek Pochyly, Jiri Obrovsky, Josef
practical solution of the above mentioned problems is very much time and Pressure pulsation, Detuning, Heterogeneous blade
383-391
Runners
Mikulasek
money consuming. The paper describes a new theoretical solution of thepassages
excitation and pressure pulsation decrease as well as extension of theoperational range with high efficiency level. The new concept to decrease thevibrations and pressure pulsations is based on a heterogeneous runner blade
geometry generation. The new concept of the runner geometry design was
numerically tested at a low specific speed pump turbine, see Fig. 1, and basic
points of the concept are presented in this paper.

The paper concerns the description of the step by step development processof the new fixed blade runner called "Mixer" suitable for the uprating of theFrancis turbines units installed at the older low head hydropower plants. In thepaper the details of hydraulic and mechanical design are presented. Since therotational speed of the new runner is significantly higher then the rotational
speed of the original Francis one, the direct coupling of the turbine to thegenerator can be applied. The maximum efficiency at prescribed operational
point was reached by the geometry optimization of two most importantcomponents. In the first step the optimization of the draft tube geometry was
carried out. The condition for the draft tube geometry optimization was todesign the new geometry of the draft tube within the original bad draft tube
shape without any extensive civil works. The runner blade geometry

392-399

Development of The New High Specific Speed Fixed
Blade Turbine Runner

Ales Skotak, Josef Mikulasek, Jiri Obrovsky

400-408

Validation of a CFD model for hydraulic seals

Vincent Le Roy, François Guibault, Thi C. Vu

409-417

Experimental Study on Surge Inception in aCentrifugal Compressor

418-425

Hydrographic Model Test on Prevention against
Vortex Occurrence for Vertical Bulb Turbine

426-430

Design and Prototyping Micro Centrifugal
Compressor for Ultra Micro Gas Turbine

431-438

Large Eddy Simulation of the Dynamic Response ofan Inducer to Flow Rate Fluctuations

Hideaki Tamaki

fixed blade turbine, runner, draft tube, optimization,
optimization was carried out on the runner coupled with the draft tube
uprating, efficiency
domain. The blade geometry of the runner was optimized using automatic
direct search optimization procedure. The method used for the objectivefunction minimum search is a kind of the Nelder-Mead simplex method. The
objective function concerns efficiency, required net head and cavitation
features. After successful hydraulic design the modal and stress analysis was
carried out on the prototype scale runner. The static pressure distribution fromflow simulation was used as a load condition. The modal analysis in air and inwater was carried out and the results were compared. The final runner was
manufactured in model scale and it is going to be tested in hydrauliclaboratory. Since the turbine with the fixed blade runner does not allow
double regulation like in case of full Kaplan turbine, it can be profitably usedmainly at power plants with smaller changes of operational conditions or in
Optimization of seal geometries can reduce significantly the energetic losses ina hydraulic seal [1], especially for high head runner turbine. In the optimization
process, a reliable prediction of the losses is needed and CFD is often used.
This paper presents numerical experiments to determine an adequate CFD
model for straight, labyrinth and stepped hydraulic seals used in Francis
runners. The computation is performed with a finite volume commercial CFD CFD, SST turbulence model, hydraulic seal, straightcode with a RANS low Reynolds turbulence model. As numerical computations seal, labyrinth seal, experimental validationin small radial clearances of hydraulic seals are not often encountered in theliterature, the numerical results are validated with experimental data on
straight seals and labyrinth seals. As the validation is satisfactory enough,geometrical optimization of hydraulic seals using CFD will be studied in future
works.
An investigation of surge inception in a centrifugal compressor was done withmeasurements of steady and unsteady static pressure. Vaneless diffuser andvaned diffuser were tested. Analyses of the static pressure and the pressure
fluctuation showed that stall at the impeller leading edge occurred at first, andCentrifugal Compressor, Surge, Pressure Fluctuation,then it extended to downstream. In case of the vaneless diffuser, deterioration
Vaned Diffuserof the pressure rise in the impeller triggered instability. For the vande diffuser,
instability that was generated in the impeller propagated into the vaned
diffuser, however the pressure recovery by the vaned diffuser made theoperation of the compressor stable at low flow rate.

A vertical bulb turbine unit with elbow type draft tube has been developed
due to avoidance of complicated assembling and long standstill period at
overhaul in comparison with conventional horizontal bulb turbine unit. Before Water turbine, Air entraining vortex, Free surface flow,
Shoichi Yamato, Shogo Nakamura, Akinori Furukawa
designing the prototype vertical bulb unit, a hydrographic model test was Surge wave, Hydrographic model test
carried out to establish the ideal design concept for this innovative generatingunit.
In order to investigate the design method for a micro centrifugal compressor,
which is the most important component of an ultra micro gas turbine, animpeller having the outer diameter of 20mm was designed, manufactured andtested. The designed rotational speed is 500,000 rpm and the impeller has afully 3-dimensional shape. The impeller was rotated at 250,000 rpm in the
Toshiyuki Hirano, Hoshio Tsujita, Ronglei Gu, Gaku
present study. The experimental results of the tested compressor with the Centrifugal Compressor, Performance Characteristics,
Minorikawa
vaned and the vaneless diffusers were compared. It was found that the vaned 3-dimensional Impeller, Prediction method
diffuser attained the higher flow rate than the vaneless diffuser at the
maximum pressure ratio. In addition the maximum pressure ratio was higher
for the diffuser having a larger diffuser divergence angle at the high flow rate.
These results were compared with those obtained by the prediction method
used at the design stage.

Donghyuk Kang, Koichi Yonezawa, Tatsuya Ueda,
Nobuhiro Yamanishi, Chisachi Kato, Yoshinobu
Tsujimoto

A Large Eddy Simulation (LES) of the flow in an inducer is carried out underflow rate oscillations. The present study focuses on the dynamic response of
the backflow and the unsteady pressure performance to the flow rate
fluctuations under non-cavitation conditions. The amplitude of angularmomentum fluctuation evaluated by LES is larger than that evaluated by
RANS. However, the phase delay of backflow is nearly the same as RANS
calculation. The pressure performance curve exhibits a closed curve caused by
the inertia effect associated with the flow rate fluctuations. Compared with
Inducer, Backflow Vortex, Dynamic Response to flow
simplified one dimensional evaluation of the inertia component, therate fluctuation, Large Eddy Simulation
component obtained by LES is smaller. The negative slope of averaged
performance curve becomes larger under unsteady conditions. From theconservations of angular momentum and energy, an expression useful for theevaluation of unsteady pressure rise was obtained. The examination of eachterm of this expression show that the apparent decrease of inertia effects iscaused by the response delay of Euler's head and that the increase of negative
slope is caused by the delay of inertial term associated with the delay of
backflow response. These results are qualitatively confirmed by experiments.

439-448

Inducer Design to Avoid Cavitation Instabilities

449-455

A New Blade Profile for Bidirectional Flow Properly
Applicable to a Two-stage Jet Fan

Page

Title

Donghyuk Kang, Toshifumi Watanabe, Koichi
Yonezawa, Hironori Horiguchi, Yutaka Kawata,
Yoshinobu Tsujimoto

Three inducers were designed to avoid cavitation instabilities. This was
accomplished by avoiding the interaction of tip cavity with the leading edgeof the next blade. The first one was designed with extremely larger leadingedge sweep, the second and third ones were designed with smaller incidence
angle by reducing the inlet blade angle or increasing the design flow rate,
respectively. The inducer with larger design flow rate has larger outlet blade
angle to obtain sufficient pressure rise. The inducer with larger sweep could
suppress the cavitation instabilities in higher flow rates more than 95% ofdesign flow coefficient, owing to weaker tip leakage vortex cavity with
Inducer, Cavitation instability, Tip cavity, CFD
stronger disturbance by backflow vortices. The inducer with larger outlet blade
computation
angle could avoid the cavitation instabilities at higher flow rates, owing to theextension of the tip cavity along the suction surface of the blade. The inducer
with smaller inlet blade angle could avoid the cavitation instabilities at higher
flow rates, owing to the occurrence of the cavity first in the blade passage andits extension upstream. The cavity shape and suction performance werereasonably simulated by three dimensional CFD computations under thesteady cavitating condition, except for the backflow vortex cavity. The
difference in the growth of cavity for each inducer is explained from thedifference of the pressure distribution on the suction side of the blades.

A reversible axial flow fan called jet fan has been widely used for longitudinal
ventilation in road tunnels to secure a safe and comfortable environment costeffectively. As shifting the flow direction is usually made by only switching therotational direction of an electric motor due to heavy duty, rotor blades
having identical aerodynamic performance for bidirectional flow should be Blade profile, Wall curvature, Bidirectional flow, Jet
Michihiro Nishi, Shuhong Liu, Kouichi Yoshida, Minoru
necessary. However, such aerodynamically desirable blades haven't beenfan, Aerodynamic performance, Turbulent flow
Okamoto, Hiroyasu Nakayama
developed sufficiently, since most of the related studies have been done from analysis
the viewpoint of unidirectional flow. In the present paper, we demonstrate amethod to profile the blade section suitable for bidirectional flow, which isvalidated by studying the aerodynamic performances of rotor blades of a twostage jet fan experimentally and numerically.
Author

Abstract

Keywords

1-10

Measurements of Minute Unsteady Pressure on
Three-Dimensional Fan with Arbitrary Axis Direction

Katsuya Hirata, Takuya Fuchi, Yusuke Onishi, Akira
Takushima, Seiji Sato, Jiro Funaki

The present study is a fundamental approach to develop the measuring
technology for minute fluctuating pressures on the three-dimensional bladesurfaces of the fan which rotates with an arbitrary rotation-axis direction. In
this situation, we are required to correct the centrifugal-force effect, thegravitational-force effect and the other leading-error effects for accurate
measurements of the minute pressures. The working fluid is air. A pressure Fluctuating pressure, Pressure measurement, Unsteadytransducer rotating with an arbitrary attitude is closely sealed by a twofold pressure, Fan, Low speed
shroud system. The rotational motion with an arbitrary attitude is produced by
fixing the pressure transducer to the cantilever which is connected to a motordriven disc of 500mm in diameter and 5mm in thickness. As a result, we havequantitatively determined main governing effects upon the non-effective
component of the pressure-transducer signal
The performance of the crossover system of a centrifugal compressor stage
consisting of static components of 180° U-bend, return channel vanes and exit
ducting with a 90° bend is investigated. This study is confined to the

11-19

20-28

29-38

Vol. 3, No.
1,
JanuaryMarch,
2010

39-49

50-57

58-66

Flow Investigations in the Crossover System of aCentrifugal Compressor Stage

Design and Analysis of a Controlled Diffusion Aerofoil
Section for an Axial Compressor Stator and Effect ofIncidence Angle and Mach No. on Performance of
CDA

Surrogate Modeling for Optimization of a Centrifugal
Compressor Impeller

Performance Improvement of High Speed Jet Fan

Cavitation Surge Suppression of Pump Inducer with
Axi-asymmetrical Inlet Plate

A Two-Dimensional Study of Transonic Flow
Characteristics in Steam Control Valve for Power Plant

K. Srinivasa Reddy, G. V. Ramana Murty, A Dasgupta,
K. V. Sharma

assessment of performance of the crossover system by varying the shape ofthe return channel vanes. For this purpose two different types of Return
Channel Vanes (RCV1 and RCV2) were experimentally investigated. The
performance of the crossover system is discussed in terms of total pressure
loss coefficient, static pressure recovery coefficient and vane surface pressure
distribution. The experimentation was carried out on a test setup in which
static swirl vanes were used to simulate the flow at the exit of an actualCentrifugal Compressor, Return Channel Vanes, Inlet
centrifugal compressor impeller with a design flow coefficient of 0.053. The Flow Angle, Swirl Angle, Performance, Vane Surface,swirl vanes are connected to a mechanism with which the flow angle at the Pressure Coefficient
inlet of U-bend could be altered. The measurements were taken at fivedifferent operating conditions varying from 70% to 120% of design flow rate.
On an overall assessment RCV1 is found to give better performance incomparison to RCV2 for different U-bend inlet flow angles. The performanceof RCV2 was verified using numerical studies with the help of a CFD Code.
Three dimensional sector models were used for simulating the flow throughthe crossover system. The turbulence was predicted with standard k-ε, 2equation model. The iso-Mach contour plots on different planes anddevelopment of secondary flows were visualized through this study.

Nilesh P. Salunke, S. A. Channiwala

This paper deals with the Design and Analysis of a Controlled Diffusion
Aerofoil (CDA) Blade Section for an Axial Compressor Stator and Effect ofincidence angle and Mach No. on Performance of CDA. CD blade section has
been designed at Axial Flow Compressor Research Lab, Propulsion Division of
National Aerospace Laboratories (NAL), Bangalore, as per geometric procedure
specified in the U.S. patent (4). The CFD analysis has been performed by a 2-D
Euler code (Denton's code), which gives surface Mach No. distribution on the
CDA, MCA, Blade Profile, Transonic compressor
profiles. Boundary layer computations were performed by a 2-D boundary
design, Axial Flow Compressor
layer code (NALSOF0801) available in the SOFFTS library of NAL. The effect ofvariation of Mach no. was performed using fluent . The surface Mach no.
distribution on the CD profile clearly indicates lower peak Mach no. than MCA
profile. Further, boundary layer parameters on CD aerofoil at respective
incidences have lower values than corresponding MCA blade profile. Total
pressure loss on CD aerofoil for the same incidence range is lower than MCA
blade profile.

Jin-Hyuk Kim, Jae-Ho Choi, Kwang-Yong Kim

This paper presents a procedure for the design optimization of a centrifugal
compressor. The centrifugal compressor consists of a centrifugal impeller,
vaneless diffuser and volute. And, optimization techniques based on the radialbasis neural network method are used to optimize the impeller of a centrifugal
compressor. The Latin-hypercube sampling of design-of-experiments is used
to generate the thirty design points within design spaces. Three-dimensional
Reynolds-averaged Navier-Stokes equations with the shear stress transport
Centrifugal compressor, Impeller, Meridian plane,
turbulence model are discretized by using finite volume approximations andOptimization, Pressure ratio, Efficiency
solved on hexahedral grids to evaluate the objective function of the total-tototal pressure ratio. Four variables defining the impeller hub and shroud
contours are selected as design variables in this optimization. The results of
optimization show that the total-to-total pressure ratio of the optimized shapeat the design flow coefficient is enhanced by 2.46% and the total-to-totalpressure ratios at the off-design points are also improved significantly by thedesign optimization.

Young-Seok Choi, Joon-Hyung Kim, Kyoung-Yong
Lee, Sang-Ho Yang

In this paper, a numerical study has been carried out to investigate theinfluence of jet fan design variables on the performance of a jet fan. In orderto achieve an optimum jet fan design and to explain the interactions between
the different geometric configurations in the jet fan, three-dimensional
computational fluid dynamics and the DOE method have been applied. Several
Optimum design, Jet fan, Rotor blade, Stator blade,geometric variables, i.e., hub-tip ratio, meridional shape, rotor stagger angle,
Bell-mouth, CFD (Computational Fluid Dynamics),
number of rotor-stator blades and stator geometry, were employed to
DOE (Design of Experiments)
improve the performance of the jet fan. The objective functions are defined as
the exit velocity and total efficiency at the operating condition. Based on the
results of computational analyses, the performance of the jet fan was
significantly improved. The performance degradations when the jet fan isoperated in the reverse direction are also discussed.

Jun-Ho Kim, Koichi Ishzaka, Satoshi Watanabe,
Akinori Furukawa

The attachment of inducer in front of main impeller is a powerful method toimprove cavitation performance. Cavitation surge oscillation, however, often
occurs at partial flow rate and extremely low suction pressure. As thecavitation surge oscillation with low frequency of about 10 Hz occurs in aclose relation between the inlet backflow cavitation and the growth of blade
cavity into the throat section of blade passage, one method of installing anaxiasymmetrical plate upstream of inducer has been proposed to suppress theoscillation. The inlet flow distortion due to the axi-asymmetrical plate makes Turbomachinery, Pump inducer, Cavitation surge
different elongations of cavities on all blades, which prevent the flow from suppression, Axi-asymmetrical inlet plate
becoming simultaneously unstable at all throat sections. In the present study,changes of the suppression effects with the axial distance between the inducer
inlet and the plate and the changes with the blockage ratios of plate area tothe cross-sectional area of inducer inlet are investigated for helical inducers
with tip blade angles of 8° and 14°. Then a conceivable application will be
proposed to suppress the cavitation surge oscillation by installing axiasymmetrical inlet plate.

Koichi Yonezawa, Yoshinori Terachi, Toru Nakajima,
Yoshinobu Tsujimoto, Kenichi Tezuka, Michitsugu
Mori, Ryo Morita, Fumio Inada

A steam control valve is used to control the flow from the steam generator to
the steam turbine in thermal and nuclear power plants. During startup andshutdown of the plant, the steam control valve is operated under a partial flow
conditions. In such conditions, the valve opening is small and the pressure
deference across the valve is large. As a result, the flow downstream of thevalve is composed of separated unsteady transonic jets. Such flow patterns
often cause undesirable large unsteady fluid force on the valve head andTransonic flow, Control valve, Flow oscillation
downstream pipe system. In the present study, various flow patterns areinvestigated in order to understand the characteristics of the unsteady flow
around the valve. Experiments are carried out with simplified two-dimensional
valve models. Two-dimensional unsteady flow simulations are conducted inorder to understand the experimental results in detail. Scale effects on the flow
characteristics are also examined. Results show three types of oscillating flow
pattern and three types of static flow patterns.

Severe flexural vibration of the rotor shaft of a Francis turbine runner was
experienced in the past. It was shown that the vibration was caused by thefluid forces and moments on the backshroud of the runner associated with theleakage flow through the back chamber. The aim of the present paper is to

Rotordynamic Instabilities Caused by the Fluid Force
67-79

Moments on the Backshroud of a Francis Turbine
RunnerBingwei Song, Hironori Horiguchi, Zhenyue Ma,
Yoshinobu Tsujimoto

study the self-excited rotor vibration caused by the fluid force moments on
the backshroud of a Francis turbine runner. The rotor vibration includes two
fundamental motions, one is a whirling motion which only has a linear
displacement and the other is a precession motion which only has an angulardisplacement. Accordingly, two types of fluid force moment are exerted on therotor, the moment due to whirl and the moment due to precession. The main

Rotordynamic instabilities, fluid force moments,
focus of the present paper is to clarify the contribution of each moment to theFrancis turbine runner, backshroud
self-excited vibration of an overhung rotor. The runner was modeled by a disk
and the whirl and the precession moments on the backshroud of the runnercaused by the leakage flow were evaluated from the results of model tests
conducted before. A lumped parameter model of a cantilevered rotor wasused for the vibration analysis. By examining the frequency, the damping rate,
the amplitude ratio of lateral and angular displacements for the cases withlonger and shorter overhung rotor, it was found that the precession moment
is more important for smaller overhung rotors and the whirl moment is more
important for larger overhung rotors, although both types of moment due tothe leakage flow can cause self-excited vibration of an overhung rotor.

80-90

Changkun Chen, Christophe Nicolet, Koichi Yonezawa,
Mohamed Farhat, Francois Avellan, Kazuyoshi
Miyagawa, Yoshinobu Tsujimoto

91-101

Experimental Study and Numerical Simulation of
Cavity Oscillation in a Conical Diffuser

Changkun Chen, Christophe Nicolet, Koichi Yonezawa,
Mohamed Farhat, Francois Avellan, Kazuyoshi
Miyagawa, Yoshinobu Tsujimoto

Changkun Chen, Christophe Nicolet, Koichi Yonezawa, Mohamed Farhat,
Francois Avellan, Kazuyoshi Miyagawa, Yoshinobu Tsujimoto

Page

Title

Author

Abstract

Computational Study of Magnetically Suspended
102-112 Centrifugal Blood Pump (The First Report: Main Flowand Gap Flow)

113-121

Computational Fluid Dynamics of Cavitating Flow in
Mixed Flow Pump with Closed Type Impeller

122-128

Cavitation in Pump Inducer with Axi-asymmetrical
Inlet Plate Observed by Multi-cameras

129-136

Internal Flow of a Two-Bladed Helical Inducer at an
Extremely Low Flow Rate

Suppression of Cavitation Instabilities in an Inducer
137-149 by Circumferential Groove and Explanation of Higher
Frequency Components

Vol. 3, No.
2, AprilJune, 2010

The cavity oscillation with swirling flow in hydraulic power generating systems
was studied by a simple experiment and numerical simulation. Several types offluctuation were observed in the experiment, including the cavitation surge
Draft tube surge, diffuser effect, swirl effect, cavitation
caused by the diffuser effect and the vortex precession by the swirling flow.
Both cavitation surge and vortex precession were simulated by CFD. Detailed
flow structure was examined through flow visualization and CFD.

Experimental Study and Numerical Simulation of
Cavity Oscillation in a Diffuser with Swirling Flow

Draft tube surge, diffuser effect, cavitation

Keywords

Artificial heart pumps have attracted the attention of researchers around theworld as an alternative to the organ used in cardiac transplantation.
Conventional centrifugal pumps are no longer considered suitable for longterm application because of the possibility of occurrence of blood leakage andthrombus formation around the shaft seal. To overcome this problem posedby the shaft seal in conventional centrifugal pumps, the magneticallysuspended centrifugal pump has been developed; this is a sealless rotor pump,which can provide contact-free rotation of the impeller without leading tomaterial wear. In Europe, clinical trials of this pump have been successfully Artificial Heart, Blood Pump, Computational Fluid
Yoshifumi Ogami, Daisuke Matsuoka, Masaaki Horie
performed, and these pumps are commercially available. One of the aims of Dynamics, Internal Flow, Turbomachinery
our study is to numerically examine the internal flow and the effect of leakage
flow through the gap between the impeller and the pump casing on theperformance of the pump. The results show that the pressure head increases
compared with the pump without a gap for all flow rates because of theleakage of the fluid through the gap. It was observed that the leakage flowrate in the pump is sufficiently large; further, no stagnant fluid or dead flow
regions were observed in the pump. Therefore, the present pump canefficiently enhance the washout effect.
LES(Large Eddy Simulation) with a cavitation model was performed to
calculate an unsteady flow for a mixed flow pump with a closed type impeller.
First, the comparison between the numerical and experimental results wasdone to evaluate a computational accuracy. Second, the torque acting on theblade was calculated by simulation to investigate how the cavitation caused
the fluctuation of torque. The absolute pressure around the leading edge on
the suction side of blade surface had positive impulsive peaks in both thenumerical and experimental results. The simulation showed that those peaks
were caused by the cavitaion which contracted and vanished around theleading edge. The absolute pressure was predicted by simulation with -10%
error. The absolute pressure around the trailing edge on the suction side ofblade surface had no impulsive peaks in both the numerical and experimental
Cavitation, Numerical Simulation, Fluctuating
Katsutoshi Kobayashi, Yoshimasa Chiba
results, because the absolute pressure was 100 times higher than the saturated
Hydraulic Force, Pump, Bladevapor pressure. The simulation results showed that the cavitation was
generated around the throat, then contracted and finally vanished. The
simulated pump had five throats and cavitation behaviors such as contraction
and vanishing around five throats were different from each other. For instance,
the cavitations around those five throats were not vanished at the same time.
When the cavitation was contracted and finally vanished, the absolute pressure
on the blade surface was increased. When the cavitation was contracted
around the throat located on the pressure side of blade surface, the pressure
became high on the pressure side of blade surface. It caused the 1.4 times
higher impulsive peak in the torque than the averaged value. On the other
hand, when the cavitation was contracted around the throat located on thesuction side of blade surface, the pressure became high on the suction side of
The attachment of inducer in front of main impeller is a powerful method toimprove cavitation performance; however, cavitation surge oscillation with low
frequency occurs with blade cavity growing to each throat section of blade
passage simultaneously. Then, one conceptual method of installing suction
axi-asymmetrical plate has been proposed so as to keep every throat passage
away from being unstable at once, and the effect on suppression of the
Pump inducer, Cavitation surge suppression, AxiJun-Ho Kim, Takashi Atono, Koichi Ishizaka, Satoshi
oscillation were investigated. In the present study, cavitation behaviors in the asymmetrical inlet plate, Multi-cameras observation
Watanabe, Akinori Furukawa
inducer is observed with distributing multi-cameras circumferentially, recording systemsimultaneously and reconstructing multi-photos on one plane field as moving
a linear cascade. Observed results are utilized for discussion with othermeasuring results as casing wall pressure distribution. Then the suppression
mechanism of oscillation by installing axi-asymmetrical inlet plate will beclarified in more details.

Satoshi Watanabe, Naoki Inoue, Koichi Ishizaka,
Akinori Furukawa, Jun-Ho Kim

The attachment of inducer upstream of main impeller is an effective method
to improve the suction performance of turbopump. However, various types ofcavitation instabilities are known to occur even at the designed flow rate aswell as in the partial flow rate region. The cavitation surge occurring at partial
flow rates is known to be strongly associated with the inlet back flow. In the Inducer, Internal flow, Cavitation, Laser Doppler
present study, in order to understand the detailed structure of internal flow of velocimetry measurement, Computational fluid
inducer, we firstly carried out the experimental and numerical studies of non- dynamics
cavitating flow, focusing on the flow field near the inlet throat section andinside the blade passage of a two bladed inducer at a partial flow rate. The
steady flow simulation with cavitation model was also made to investigate thedifference of flow field between in the cavitating and noncavitating conditions.

Donghyuk Kang, Yusuke Arimoto, Koichi Yonezawa,
Hironori Horiguchi, Yutaka Kawata, Chunill Hah,
Yoshinobu Tsujimoto

The purpose of the present research is to suppress cavitation instabilities byusing a circumferential groove. The circumferential groove was designed basedon CFD so that the tip leakage vortex is trapped by the groove and does notinteract with the next blade. Experimental results show that the groove canInducer, Cavitation instabilities, Circumferential
suppress rotating cavitation, asymmetric cavitation and cavitation surge.
groove, Higher frequency component
However, weak instabilities with higher frequency could not be suppressed by
the groove. From the analysis of pressure pattern similar to that for rotorstator interaction, it was found that the higher frequency components arecaused by the interaction of backflow vortices with the inducer blades.

Vol. 3, No.
2, AprilJune, 2010

Laidback fan shaped film-cooling hole is formulated numerically andoptimized with the help of three-dimensional numerical analysis, surrogate
methods, and the multi-objective evolutionary algorithm. As Pareto optimal
front produces a set of optimal solutions, the trends of objective functions
with design variables are predicted by hybrid multi-objective evolutionary
algorithm. The problem is defined by four geometric design variables, the150-159

Multi-objective Optimization of a Laidback Fan
Shaped Film-Cooling Hole Using Evolutionary
Algorithm

injection angle of the hole, the lateral expansion angle of the diffuser, theforward expansion angle of the hole, and the ratio of the length to the
Ki-Don Lee, Afzal Husain, Kwang-Yong Kim

160-168

Prediction of Axial Thrust for Mixed-Flow Pumps with
Vaned Diffuser by Using CFD

Ichiro Harada, Katsutoshi Kobayasi, Shigeyoshi Ono

170-180

Cavitation Instabilities in Turbopump Inducers Analyses in 1-3 dimensions -Yoshinobu Tsujimoto, Hironori Horiguchi, Koichi
Yonezawa

181-203

Performance Prediction of Vertical Submersible
Centrifugal Slurry Pump

Lifetime Prediction of Film Cooling Systems with andwithout Thermal Barrier Coating

Kyung Min Kim, Dong Hyun Lee, Hyung Hee Cho

Page

Title

Author221-226227-234

Unsteady Swirling Flows Arising in Straight Tubes

A Study on Performance Conversion from Model toPrototype

Numerical Study on Mixing Performance of Straight
Groove Micromixers

numerical simulation results, the Response Surface Approximation model areconstructed for each objective function and a hybrid multi-objective
evolutionary algorithm is applied to obtain the Pareto optimal front. The
clustered points from Pareto optimal front were evaluated by flow analysis.
These designs give enhanced objective function values in comparison with theexperimental designs.
It is important in pump design that the axial thrust of mixed-flow pump ispredicted with high accuracy. In this paper, predictions of the axial thrust werecarried out with CFD for mixed-flow pumps of three specific speeds. The
region concerning the axial thrust prediction was picked out, and was divided
into two parts. One of them was hydraulic part, which included the impeller Mixed-Flow Pump, Impeller, Vaned Diffuser, Axial
and the vaned diffuser. The other was the rear part of impeller. These parts Thrust, CFD, Prediction, Experimental Result
were calculated and evaluated individually. The CFD results were comparedwith experimental ones. They showed good agreements. It is shown that theaxial thrust for a mixed-flow pump can be predicted by using CFD withpractical accuracy.
Stability analyses of 1-3 dimensional cavitating flow through turbopump
inducers are reviewed with a special focus on the cause of cavitation
instabilities. In one-dimensional analysis, cavitation is modeled with thecavitation compliance, defined as the decrease of cavity volume due to theincrease of inlet pressure, and the mass flow gain factor, defined as thedecrease of cavity volume due to the increase of flow rate. It was shown thatthe positive mass flow gain factor is the cause of cavitation surge and rotating
cavitation. In two-dimensional stability analysis, the blade surface cavity ismodeled by a free streamline with a constant pressure. It is shown that various
modes of cavitation instabilities start to occur when the cavity length becomes
about 65% of the blade spacing. It was found that there is a region near thecavity trailing edge in which the incidence angle to the next blade isdecreased. This flow occurs to satisfy the continuity equation near the cavity Inducer, Cavitation, Instability, Stability Analysis, CFD

closure. The cavitation instabilities start to occur when this region starts tointeract with the leading edge of the next blade. In three-dimensional realflows, cavitation occurs mostly near the tip. Cavitation instabilities are
simulated by three dimensional unsteady cavitating CFD. By separating out the
disturbance caused by cavitation, it was found that there exists a flow
component towards the trailing edge of tip cavities to fill up the volume ofcollapsing bubbles. This disturbance flow has an effect to reduce the incidence
angle to the next blade. It was found that cavitation instabilities start to occur
when this disturbance flow starts to interact with the leading edge of the next
blade. So, it was found that the steady cavity length at the tip is the mostimportant parameter in three dimensional real flow. Thus, it was found that thecontinuity equation plays the most important role in the mechanism of
Performance prediction methodology for centrifugal submersible slurry pumphas been presented in this paper. An in-depth study on various energy-headlosses occurring through the pump flow in rotating reference frame has been
carried out in this research work. Head-flow characteristics of the centrifugal
pump have been accomplished in two stages. First performance of thecentrifugal pump with clear water has been predicted by analyzing and
Lal Gopal Das, Prasanta Kumar Sen, Timir Kanti Saha,
centrifugal slurry pump, head loss, performance,
deducting head losses from the theoretical head. Effects of solid particles size,
Arunabha Chanda
concentration, impeller, diffuser
specific gravity and concentration on pump slurry flow have been investigated.
Additional head losses due to solid particles in the slurry have been predicted,
analyzed and then deducted from clear water head to establish theperformance of centrifugal slurry pump. The performance of centrifugal slurrypump has been predicted at with accuracy of 88 to 90 % for solid
concentration of 18 % to 5 % by volume.

204-210211-220

diameter of the hole, to maximize the film-cooling effectiveness compromising Film-cooling, Numerical analysis, Multi-objectivewith the aerodynamic loss. The objective function values are numerically
optimization, Response Surface Approximation
evaluated through Reynolds- averaged Navier-Stokes analysis at the designs
that are selected through the Latin hypercube sampling method. Using these

The present study investigated temperature, thermal stress, and the lifetime infilm cooling systems with and without thermal barrier coating. 3D-numericalsimulations using a FEM commercial code were conducted to calculate
distributions of temperature and thermal stresses. In the simulations, thesurface boundary conditions used the surface heat transfer coefficients andGas turbine heat transfer, Film cooling, Thermal
adiabatic wall temperature which were converted from the Sherwood numbers
analysis, Lifetime prediction, Finite element method
and impermeable wall effectiveness obtained from previous mass transfer
experiments. Then, the lifetime of the film cooling systems is predicted using
thermal analysis data and the material creep data. The minimum lifetime isapproximately 1,100 hours on the sides of the hot side surface in case without
TBC.
Abstract

Keywords

Hiromu Tsurusaki

The objective of this study is to clarify the occurrence of the high-speed modeof unsteady swirling flows in straight tubes. The unsteady flows generated in
the tube were measured by means of a semiconductor-type pressuretransducer and an FFT analyzer. The high-speed mode measured has
rotational speed which is approximately equal to or higher than the peripheral
Unsteady Flow, Swirling Flow, Whirling Vortex,
velocity of the swirling flow. The unsteady flow is due to cell rotation in thePressure Fluctuation, Rotating stallcircumferential direction of the tube. The occurrence of the high-speed mode
was confirmed, and the characteristics (rotational speed, pressure amplitude,
and phase) of this mode were clarified. In order to understand the measured
unsteady flows, the three dimensional vortex core profiles were discussed
based on the distributions of the pressure amplitude and phase.

Masao Oshima

A prototype pump performance converted from that of a model pump shows
an increase in efficiency. This paper discusses whether such increase is related
to an increase in pump head and/or to a decrease in input power, based on
the relationship between the tangential force on impeller blades, head loss
Performance conversion, Model pump, Prototype
and input power. This study revealed that the efficiency increase was brought
pump, Efficiency increase, Scale effectabout not only by an increase in head, but also by a decrease in input power,
as the tangential force on the blades constitutes a part of the input power ofa pump. A solution is proposed on how the hydraulic efficiency increase of a
prototype pump should be related to its head and input power.

Hossain Shakhawat, Kwang-Yong Kim

Numerical analyses have been performed to investigate the effects ofgeometric parameters of a straight grove micromixer on mixing performanceand pressure drop. Three-dimensional Navier-Stokes equations with twoworking fluids, water and ethanol have been used to calculate mixing index
and pressure drop. A parametric study has been carried out to find the effectsof the number of grooves per cycle, arrangement of patterned walls, andadditional grooves in triangular dead zones between half cycles of grooves.
Micromixer, Straight Groove, Numerical Analysis,
The three arrangements of patterned walls in a micromixer, i.e., single wall
Mixing, Navier-Stokes Equations, Pressure Droppatterned, both walls patterned symmetrically, and both walls patterned
asymmetrically, have been tested. The results indicate that as the number ofgrooves per cycle increases the mixing index increases and the pressure drop
decreases. The microchannel with both walls patterned asymmetrically shows
the best mixing performance among the three different arrangements ofpatterned walls. Additional grooves confirm the better mixing performanceand lower pressure drop.

Recent studies on the moment whirl due to leakage flow in the back shroud
clearance of hydro-turbine runners or centrifugal pump impellers are
summarized. First, destabilizing effect of leakage flow is discussed for lateral
vibrations using simplified models. Then it is extended to the case of whirling

235-244

Moment Whirl due to Leakage Flow in the Back
Shroud Clearance of a Rotor

Yoshinobu Tsujimoto, Zhenyue Ma, Bingwei Song,Hironori Horiguchi

motion of an overhung rotor and the criterion for the instability is obtained.
The fluid moment caused by a leakage clearance flow between a rotating disk
and a stationary casing was obtained by model tests under whirling andprecession motion of the disk. It is shown that the whirl moment always
Rotordynamic Instability, Fluid Force Moment,
destabilizes the whirl motion of the overhung rotor while the precession
Whirling Motion, Precession Motion, Leakage Flowmoment destabilizes the precession only when the precession speed is lessthan half the rotor speed. Then vibration analyses considering both whirl andprecession are made by using the hydrodynamic moments determined by themodel tests. For larger overhung rotors, the whirl moment is more importantand cause whirl instability at all rotor speed. On the other hand, for smaller
overhung rotors, the precession moment is more important and cancels theVol. 3, No.
3, JulySeptember, 2010destabilizing effect of the whirl moment.

245-252

Air-Water Two-Phase Flow Performances ofCentrifugal Pump with Movable Bladed Impeller andEffects of Installing Diffuser Vanes

Shinji Sato, Akinori Furukawa

253-259

Investigation of Leakage Characteristics of Straightand Stepped Labyrinth Seals

Tong Seop Kim, Soo Young Kang

260-270

Study of the Flow in Centrifugal Compressor

Cheng Xu, Ryoichi Samuel Amano

Page

Title

Author271-278279-284285-291

Performance and Flow Condition of Contra-rotating
Small-sized Axial Fan at Partial Flow Rate

Tip Clearance Losses - A Physical Based Scaling
MethodPhysical Model Investigation of a Compact Waste
Water Pumping Station

Toru Shigemitsu, Junichiro Fukutomi, Yuki Okabe,
Kazuhiro Iuchi

Peter F. Pelz, Sascha Karstadt

Kilian Kirst, D.-H. Hellmann, Bernd Kothe, Peer
SpringerIt's known that pump head of centrifugal impeller with lager blade outlet
angle is kept higher in air-water two phase flow condition, though theefficiency in water single phase flow condition is inferior. In the present study,a centrifugal impeller with variable blade outlet angles, that has higher
efficiencies in both water single phase flow and air-water two phase flow
conditions, is proposed. And the performances of the centrifugal impeller withvariable blade outlet angles were experimentally investigated in both flow
conditions of single and two-phase. In addition, effects of installing diffuservanes on the performances of centrifugal pump with movable bladed impeller Centrifugal pump, Variable blade angle, Air-Water
were also examined. The results are as follows: (1) The movable bladed
two-phase flow performance, Diffuser vane
impeller that proposed in this study is effective for higher efficiency in bothwater single phase and air-water two phase flow conditions. (2) When diffuservanes are installed, the efficiency of movable bladed impeller decreases
particularly at large water flow rate in water single-phase flow condition; (3)The performances of movable bladed impeller are improved by installing ofdiffuser vanes in air-water two-phase flow condition at relatively small water
rate. The improvement by installing of diffuser vanes however disappears atlarge water flow rate.
Leakage characteristics of two labyrinth seals with different configurations(straight vs stepped) were investigated. Leakage flows were predicted bycomputational fluid dynamics (CFD) for the two configurations and comparedwith test data. A semi-analytical leakage prediction tool was also tried to
predict the leakage. It was confirmed that the CFD gives quite good
agreements with test data. The analytical tool also yielded similar leakage labyrinth seal, straight seal, stepped seal, leakage,
behaviors with test results, but the overall agreement with test data was not as flow function, clearance
good as that of the CFD. The effect of flow direction in the stepped seal on
leakage flow was examined. The dependence of leakage performance, in termsof flow function, on the seal clearance size was investigated. Flow function
decreased with decreasing clearance in the straight seal, while the trend wasreversed in the stepped seal.
Reducing the losses of the tip clearance flow is one of the keys in an
unshrouded centrifugal compressor design and development because tip
clearances are large in relation to the span of the blades and also centrifugal
compressors produce a sufficiently large pressure rise in single stage. This
problem is more acute for a low flow high-pressure ratio impeller design. The
large tip clearance would cause flow separations, and as a result it would drop
both the efficiency and surge margin. Thus a design of a high efficiency andwide operation range low flow coefficient centrifugal compressor is a greatchallenge. This paper describes a recent development of high efficiency andwide surge margin low flow coefficient centrifugal compressor. A viscous
centrifugal compressor, flow separation, static
turbomachinery optimal design method developed by the authors for axial
efficiency, turbomachinery, impeller, surge
flow machine was further extended and used in the centrifugal compressor
design. The compressor has three main parts: impeller, a low solidity diffuserand volute. The tip clearance is under a special consideration in this design toallow impeller insensitiveness to the clearance. A patented three-dimensional
low solidity diffuser design method is used and applied to this design. The
compressor test results demonstrated to be successful to extend the lowsolidity diffusers to high-pressure ratio compressor. The compressor stage
performance showed the total to static efficiency of the compressor being
about 85% and stability range over 35%. The test results are in good
agreement with the design.
Abstract

Keywords

Small-sized axial fans are used as air cooler for electric equipments. But there
is a strong demand for higher power of fans according to the increase ofquantity of heat from electric devices. Therefore, higher rotational speed
design is conducted, although, it causes the deterioration of efficiency and theincrease of noise. Then the adoption of contra-rotating rotors for the smallsized axial fan is proposed for the improvement of performance. In the present Small-sized axial fan, Contra-rotating rotors,
paper, the performance curves of the contra-rotating small-sized axial fan with Performance, Internal flow, Partial flow rate, Numerical
100mm diameter are shown and the velocity distributions at a partial flow rate analysis
at the inlet and the outlet of each front and rear rotor are clarified withexperimental results. Furthermore, the flow conditions between front and rearrotors of the contra-rotating small-sized axial fan are investigated bynumerical analysis results and causes of the performance deterioration of thecontra-rotating small-sized axial fan at the partial flow rate is discussed.
Tip clearance losses occur in every turbomachine. To estimate the losses in
efficiency it is important to understand the mechanism of this secondary flow.
Tip clearance losses are mainly caused by a spiral vortex formed on thesuction side of the blade of a turbomachine, which induces a drag and also
Tip Clearance Losses, , ,, Scaling, Vortex, Prandtl
has an influence on the incident flow of the blades. In this paper a physicalbased scaling method is developed out of an analytical ansatz for the tip
clearance losses. This scaling method is validated by measurements on an axial
fan with five different tip clearances.
To provide required flow rates of cooling or circulating water properly,
approach flow conditions of vertical pump systems should be in compliancewith state of the art acceptance criteria. The direct inflow should be vortex
free, with low pre-rotation and symmetric velocity distribution. Physical model
investigations are common practice and the best tool of prediction toevaluate, to optimize and to document flow conditions inside intake structuresphysical model investigation, waste water, pumping
for vertical pumping systems. Optimization steps should be accomplished withstationrespect to installation costs and complexity on site. The report shows
evaluation of various approach flow conditions inside a compact waste water
pumping station. The focus is on the occurrence of free surface vortices andthe evaluation of air entrainment for various water level and flow rates. The
presentation of the results includes the description of the investigated intake
structure, occurring flow problems and final recommendations.

292-300

A Numerical Study on Cavitation Suppression Using
Local Cooling

Yuan-yuan Zhang, Xiao-jing Sun, Dian-gui Huang

This study strives to develop an effective strategy to inhibit cavitation
inception on hydrofoils by using local cooling technique. By setting up atemperature boundary condition and cooling a small area on the uppersurface of a hydrofoil, the fluid temperature around the cooling surface will bedecreased and thereby the corresponding liquid saturation pressure will drop
CFD, cavitation inception, cavitation suppression, local
below the lowest absolute pressure within the flow field. Hence, cavitation cancooling temperature, surface roughness
never occur. In this paper, a NACA0015 hydrofoil at 4° angle of attack wasnumerically investigated to verify the effectiveness of the proposed technique.
The CFD results indicate that the cooling temperature and the cooling surface
roughness are the critical factors affecting the success of such technique used
for cavitation suppression.

301-308

Hydraulic Runner Design Method for Lifetime

Michel Sabourin, Denis Thibault, David-Alexandre
Bouffard, Martin Lévesque

Quest for reliability of hydraulic runners is a concern for all mature electricity
producers. The fatigue damage caused by dynamics loads is frequently theroot cause of runner failure. This paper presents the damage tolerance
approach based on fracture mechanics as the method chosen by Alstom andHydro-Québec to predict effects of damage on runner lifetime andRunner Design, Fatigue, Lifetime, Fracture Mechanics,
consequently to be use as a design method. This is sustained by a research on
Material Properties, Runner Failure
fracture mechanics properties of runner materials and by recommendations on
the strategy to define a safety margin for design. The acquired knowledge
permits to identify potential improvement of the runner lifetime without
significant cost increase, like being more specific on some chemicalcomposition or heat treatment.
Stainless steel stamping multistage pump has become the mainstream of civil
multi-stage pump. Combined with the technological features of stamping andwelding pump, the studies of design for hydraulic parts of pump were comeout. An L18(37)orthogonal experiment was designed with seven factors and309-314315-323324-331

Optimization Design of Stainless Steel Stamping
Multistage Pump Based on Orthogonal Test

Compressible Simulation of Rotor-Stator Interactionin Pump-Turbines

Thermal Effects on Cryogenic Cavitating Flows aroundan Axisymmetric Ogive

three values including blade inlet angle, impeller outer diameter, guide vane
blade number, etc. 18 plans were designed. The two stage of whole flow field
on stainless steel stamping multistage pump at design point for design was
Shi Weidong, Wang Chuan, Lu Weigang, Zhou Ling,
stamping and welding pump, orthogonal
simulated by CFD. According to the test result and optimization design with
Zhang Li
experiments, internal flows, numerical simulation
experimental research, the trends of main parameters which affect hydraulicperformance were got. After being manufactured and tested, the efficiency ofthe optimal model pump reaches 61.36% and the single head is more than 4.8
m. Compared with the standard efficiency of 53%, the design of the stainlesssteel stamping pump is successful. The result would be instructive to thedesign of Stainless steel stamping multistage pump designed by the impeller
head maximum approach.
This work investigates the influence of water compressibility on pressure
pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery,using the commercial CFD solver ANSYS-CFX. A pipe flow example withharmonic velocity excitation at the inlet plane is simulated using different griddensities and time step sizes. Results are compared with a validated code forhydraulic networks (SIMSEN). Subsequently, the solution procedure is applied
to a simplified 2.5-dimensional pump-turbine configuration in prototype withdifferent speeds of sound as well as in model scale with an adapted speed ofsound. Pressure fluctuations are compared with numerical and experimental
data based on prototype scale. The good agreement indicates that the scalingof acoustic effects with an adapted speed of sound works well. With respect toCompressible hydrodynamics, rotor-stator interaction,
Jianping Yan, Jiri Koutnik, Ulrich Seidel, Björn Hübner
pressure fluctuation amplitudes along the centerline of runner channels,
pump-turbine, unsteady CFD
incompressible solutions exhibit a linear decrease while compressible solutions
exhibit sinusoidal distributions with maximum values at half the channel
length, coinciding with analytical solutions of one-dimensional acoustics.
Furthermore, in compressible simulation the amplification of pressure
fluctuations is observed from the inlet of stay vane channels to the spiral casewall. Finally, the procedure is applied to a three-dimensional pumpconfiguration in model scale with adapted speed of sound. Normalized
Pressure fluctuations are compared with results from prototype measurements.
Compared to incompressible computations, compressible simulations provide
similar pressure fluctuations in vaneless space, but pressure fluctuations inspiral case and penstock may be much higher.

Suguo Shi, Guoyu Wang

Vol. 3, No.
4,
OctoberDecember,
2010

332-341342-351

Improved Suter Transform for Pump-Turbine
Characteristics

Two-Way Coupled Fluid Structure Interaction
Simulation of a Propeller Turbine

Cavitation in cryogenic fluids generates substantial thermal effects and strong
variations in fluid properties, which in turn alter the cavity characteristics. In
order to investigate the cavitation characteristics in cryogenic fluids, numericalsimulations are conducted around an axisymmetric ogive in liquid nitrogenand hydrogen respectively. The modified Merkle cavitation model and energy
equation which accounts for the influence of cavitation are used, and variable
thermal properties of the fluid are updated with software. A good agreement
between the numerical results and experimental data are obtained. The results
show that vapor production in cavitation extracts the latent heat ofcavitation, cryogenic fluid, thermal effect, numericalevaporation from the surrounding liquid, which decreases the local
simulation, energy equation
temperature, and hence the local vapor pressure in the vicinity of cavity
becomes lower. The cavitation characteristics in cryogenic fluids are obtainedthat the cavity seems frothy and the cavitation intense is lower. It is also foundthat when the fluid is operating close to its critical temperature, thermal effectsof cavitation are more obviously in cryogenic fluids. The thermal effect on
cavitation in liquid hydrogen is more distinctively compared with that in liquid
nitrogen due to the changes of density ratio, vapour pressure gradient andother variable properties of the fluid.

Peter K. Dörfler

Standard dimensionless parameters cannot simultaneously represent all
operation modes of a pump-turbine. They either have singularities at E=0 andmultiple values in the 'unstable' areas, or else get singular at n=0. P. Suter(1966) introduced an alternative set of variables which avoids singularity andalways remains unique-valued. This works for non-regulated pumps but not sowell for regulated machines. A modification by C.S. Martin avoids distortion at Pump turbine, water hammer, characteristics,
low load. The present paper describes further improvements for thesimulation, pulsation
representation of torque, and for closed gate (where Suter's concept does notwork). The possibility to interpolate across all operation modes is likewise
useful for representing other mechanical parameters of the machine. Practicalapplication for guide vane torque and pressure pulsation data is demonstrated
by examples.

Hannes Schmucker, Felix Flemming, Stuart Coulson

During the operation of a hydro turbine the fluid mechanical pressure loadingon the turbine blades provides the driving torque on the turbine shaft. This
fluid loading results in a structural load on the component which in turncauses the turbine blade to deflect. Classically, these mechanical stresses anddeflections are calculated by means of finite element analysis (FEA) whichapplies the pressure distribution on the blade surface calculated bycomputational fluid dynamics (CFD) as a major boundary condition. Such an
approach can be seen as a one-way coupled simulation of the fluid structureinteraction (FSI) problem. In this analysis the reverse influence of thedeformation on the fluid is generally neglected. Especially in axial machines
the blade deformation can result in a significant impact on the turbine
Two-way coupling, fluid structure interaction,
performance. The present paper analyzes this influence by means of fully twopropeller turbine, CFD, FEA, FSI, gap vortex
way coupled FSI simulations of a propeller turbine utilizing two different
approaches. The configuration has been simulated by coupling the twocommercial solvers ANSYS CFX for the fluid mechanical simulation with ANSYSClassic for the structure mechanical simulation. A detailed comparison of theresults for various blade stiffness by means of changing Young's Modulus arepresented. The influence of the blade deformation on the runner discharge
and performance will be discussed and shows for the configuration
investigated no significant influence under normal structural conditions. This
study also highlights that a two-way coupled fluid structure interaction
simulation of a real engineering configuration is still a challenging task fortoday's commercially available simulation tools.

In recent years, the market has shown increasing interest in pump-turbines.
The prompt availability of pumped storage plants and the benefits to thepower system achieved by peak lopping, providing reserve capacity, and rapid
response in frequency control are providing a growing advantage. In this352-359

Performance Optimization of High Specific Speed
Pump-Turbines by Means of Numerical Flowcontext, there is a need to develop pump-turbines that can reliably withstanddynamic operation modes, fast changes of discharge rate by adjusting thevariable diffuser vanes, as well as fast changes from pumping to turbine
operation. In the first part of the present study, various flow patterns linked tooperation of a pump-turbine system are discussed. In this context, pump andturbine modes are presented separately and different load cases are shown inPeter Kerschberger, Arno Gehrer

Simulation (CFD) and Model Testingeach operating mode. In order to create modern, competitive pump-turbine pump-turbine, CFD, multi-objective optimizer, 3Ddesigns, this study further explains what design challenges should be
Euler, 3D-RANS, model testing
considered in defining the geometry of a pump-turbine impeller. The second
part of the paper describes an innovative, staggered approach to impeller
development, applied to a low head pump-turbine project. The first level ofthe process consists of optimization strategies based on evolutionary
algorithms together with 3D in-viscid flow analysis. In the next stage, thehydraulic behavior of both pump mode and turbine mode is evaluated bysolving the full 3D Navier-Stokes equations in combination with a robust
turbulence model. Finally, the progress in hydraulic design is demonstrated bymodel test results that show a significant improvement in hydraulicperformance compared to an existing reference design.

360-368

Study of Flow Field and Pressure Distribution on a
Rotor Blade of HAWT in Yawed Flow Conditions

369-378

Flow Factor Prediction of Centrifugal Hydraulic
Turbine for Sea Water Reverse Osmosis (SWRO)

379-385

Improvement in Efficiency and Operating Range ofCentrifugal Blower Stage for Sewage Aeration Blower

386-395

Study of the Adhesive Coefficient Effect on the
Hydraulic Losses and Cavitation

Page

Title

1-13

14-24

25-32

J-Groove Technique for Suppressing Various
Anomalous Flow Phenomena in Turbomachines

Design Optimization of Mixed-flow Pump in a Fixed
Meridional Shape

Numerical Study of Inlet and Impeller Flow Structuresin Centrifugal Pump at Design and Off-design Points

This paper describes the flow field and the blade pressure distribution of ahorizontal axis wind turbine in various yawed flow conditions. These
measurements were carried out with 2.4m-diameter rotor with pressure
sensors and a 2-dimensional laser Doppler velocimeter for each azimuth angle
in a wind tunnel. The results show that aerodynamic forces of the blade based
Takao Maeda, Yasunari Kamada, Naohiro Okada, Jun
Wind Turbine, Rotor Aerodynamics, Fluid Machinery,on the pressure measurements change according to the local angle of attack
SuzukiYaw, Flow Field, Pressure Distribution
during rotation. Therefore the wake of the yawed rotor becomes asymmetricfor the rotor axis. Furthermore, the relations between aerodynamic forces andazimuth angles change according to tip speed ratio. By the experimental
analysis, the flow field and the aerodynamic forces for each azimuth angle inyawed flow condition were clarified.
The creation of the hydraulic turbine flow factor map will undoubtedly benefit
its design by decreasing both the design cycle time and product cost. In thispaper, the geometry and flow variables, which effectively affect the flow factor,
are proposed, analyzed and determined. These flow variables are further used
to create the operating condition maps by using different model approaches
categorized into Response Surface Method (RSM) and Artificial Neural
Network (ANN). The accuracies of models created by different approaches are sea water reverse osmosis, hydraulic turbine, flow
Ying Ma, Eric Kadaj, Kevin Terrasi
compared and the performances of model approaches are analyzed. The
factor, flow coefficient
influences of chosen variables and the combination of Principle Component
Analysis (PCA) and model approaches are also studied. The comparison results
between predicted and actual flow factors suggest that two-hidden-layer
Feed-forward Neural Network (FFNN), and one-hidden-layer FFNN with PCA
has the best performance on forming this mapping , and are accurate
sufficiently for hydraulic turbine design.

Kiyotaka Hiradate, Toshio Kanno, Hideo Nishida,
Yasushi Shinkawa, Satoshi Joukou

We developed a high-efficiency, wide-operating-range centrifugal blower
stage to meet the demand for reduced total energy-consumption in sewage
treatment plants. We improved the efficiency of the two-dimensional impeller
using a shape optimization tool and one-dimensional performance prediction
tool. A limit of the throat deceleration ratio was set to maintain the stallmargin of the impeller. The low solidity vaned diffuser and return channel were
designed using a sensitivity analysis with orthogonal arrays and threeCentrifugal Blower, Orthogonal Array, Numericaldimensional steady flow simulations. The low solidity diffuser was designed in Simulation, Efficiency, Operating Rangeorder to improve the performance in the low-flow-rate region. The returnchannel was designed so that the total pressure loss in the return channel was
minimized. Model tests of both the conventional and optimized blower stages
were carried out, and the efficiency and operating range of both stages werecompared. The optimized blower stage improved in stage efficiency by 3%
and in operating range by 5% compared with the conventional blower stage.

The article is focused in three areas. In the first part there are analyzed theadhesion forces at the liquid and solid surface interface. There are shown themeasured values of surface energy for different types of surfaces. The value of
surface energy is decisive for determining the extent of the surface wettability
František Pochylý, Simona Fialová, Milada Kozubková,by the liquid.The second part points to the possible negative effects of partly cavitation, wettability, adhesion force, impeller pump
Lukáš Zavadil
wettable surfaces, showing susceptibility to cavitation. The third section
describes the practical aspects of surface wettability by the liquid. Under the
new boundary conditions bases, expressing the effect of adhesion forces, there
are determined the centrifugal pump characteristics.
AuthorJunichi Kurokawa

Abstract

Keywords

In operating a turbomachine at off-design conditions various instabilities
caused by anomalous flow phenomena occur and sometimes lead to thedamage of a turbomachine. In order to avoid these phenomena various
devices characteristic to each phenomenon have been developed, however
they make turbomachines large-sized and cause efficiency drop. The present
author has developed a very simple and innovative device, termed "J-groove," J-Groove, Anomalous Flow Phenomenon, Surge,of suppressing various anomalous flow phenomena commonly by controlling Cavitation, Performance-curve Instability
the angular momentum of the main flow. It has been revealed that J-groove
makes an operation of a turbomachine stable in all flow range, causes little
efficiency drop, and can be easily applied to an existing machine. Here isreviewed totally the results of suppressing various anomalous flow phenomena
in turbomachines.

In this paper, design optimization for mixed-flow pump impellers and diffusers
has been studied using a commercial computational fluid dynamics (CFD)
code and DOE (design of experiments). We also discussed how to improve theperformance of the mixed-flow pump by designing the impeller and diffuser.
Geometric design variables were defined by the vane plane development,
which indicates the blade-angle distributions and length of the impeller anddiffusers. The vane plane development was controlled using the blade-angle ina fixed meridional shape. First, the design optimization of the defined impeller
Mixed-flow Pump, Impeller, Diffuser, Optimal Design,
Sung Kim, Young-Seok Choi, Kyoung-Yong Lee, Jungeometric variables was achieved, and then the flow characteristics were
CFD (computational fluid dynamics), DOE (design of
Ho Kimanalyzed in the point of incidence angle at the diffuser leading edge for theexperiments)
optimized impeller. Next, design optimizations of the defined diffuser shapevariables were performed. The importance of the geometric design variables
was analyzed using 2k factorial designs, and the design optimization of thegeometric variables was determined using the response surface method (RSM).
The objective functions were defined as the total head and the total efficiency
at the design flow rate. Based on the comparison of CFD results between the
optimized pump and base design models, the reason for the performance
improvement was discussed.

Kean Wee Cheah, Thong See Lee, Winoto S.H

The objective of present work is to use numerical simulation to investigate thecomplex three-dimensional and secondary flow structures developed at the
inlet and impeller in a centrifugal pump at design and off-design points. The
pump impeller is shrouded with 6 backward swept blades and with a specificspeed of 0.8574. The characteristic of the pump is measured experimentally
centrifugal pump, impeller, inlet flow structure,with straight and curved intake sections. Numerical computation is carried out
secondary flow
to investigate the pump inlet flow structures and subsequently the flow fieldwithin the centrifugal pump. The numerical results showed that strong
interaction between the impeller eye and intake section. Secondary flow
structure occurs upstream at the pump inlet has great influence on the pump
performance and flow structure within the impeller.

Concave surface boundary-layer flows are subjected to centrifugal instability
which results in the formation of streamwise counter-rotating vortices. Suchboundary layer flows have been experimentally investigated on concave
surfaces of 1 m and 2 m radius of curvature. In the experiments, to obtain
uniform vortex wavelengths, thin perturbation wires placed upstream andperpendicular to the concave surface leading edge, were used to pre-set the
wavelengths. Velocity contours were obtained from hot-wire anemometervelocity measurements. The most amplified vortex wavelengths can be pre-set
33-46

Concave Surface Boundary Layer Flows in the
Presence of Streamwise Vortices

Sonny H. Winoto, Tandiono , Dilip A. Shah, Hatsari
Mitsudharmadi

by the spanwise spacing of the thin wires and the free-stream velocity. The
Görtler vortices, concave surface, boundary layer,
velocity contours on the cross-sectional planes at several streamwise locations
instability, wall shear stress, hot-wire anemometershow the growth and breakdown of the vortices. Three different vortex growth
regions can be identified. The occurrence of a secondary instability mode isalso shown as mushroom-like structures as a consequence of the non-linear
growth of the streamwise vortices. Wall shear stress measurements on concave
surface of 1 m radius of curvature reveal that the spanwise-averaged wall
shear stress increases well beyond the flat plate boundary layer values. By presetting much larger or much smaller vortex wavelength than the mostamplified one, the splitting or merging of the streamwise vortices will
respectively occur.

47-56

Flow-Feedback for Pressure Fluctuation Mitigation
and Pressure Recovery Improvement in a Conical
Diffuser with Swirl

Our previous experimental and numerical investigations of decelerated swirlingflows in conical diffusers have demonstrated that water jet injection along thesymmetry axis mitigates the pressure fluctuations associated with theprecessing vortex rope. However, for swirling flows similar to Francis turbines
operated at partial discharge, the jet becomes effective when the jet discharge
Constantin Tanasa, Alin Bosioc, Romeo Susan-Resiga,
is larger than 10% from the turbine discharge, leading to large volumetric Francis turbine, vortex rope, pressure fluctuations,Sebastian Muntean
losses when the jet is supplied from upstream the runner. As a result, wepressure recovery coefficient, flow-feedback
introduce the flow-feedback approach for supplying the jet by using a fractionof the discharge collected downstream the conical diffuser. Experimental
investigations on mitigating the pressure fluctuations generated by theprecessing vortex rope and investigations of pressure recovery coefficient on
the cone wall with and without flow-feedback method are presented.
Radial-vaned air separators show a strong stall suppression effect in an axial
flow fans. From a survey of existing literature on the effects and the author'sdata, a possible mechanism for the significant effects has been proposed here.
The stall suppression is suggested to have been achieved by a combination of
the following several effects; (1) suction of blade and casing boundary layers
and elimination of embryos of stall, (2) separation and straightening ofreversed swirling flow from the main flow, (3) induction of the fan main flow
toward the casing wall and enhancement of the outward inclination of
Axial Flow Fan, Stall Suppression, Air Separator,
meridional streamlines across the rotor blade row, thus keeping the Euler head Vortex Ring, Internal Flow
increase in the decrease in fan flow rate, and (4) reinforcement of axisymmetric structure of the main flow. These phenomena have been induced
and enhanced by a stable vortex-ring encasing the blade tips and the air
separator. These integrated effects appear to have caused the great stall
suppression effect that would have been impossible by other types of stall
prevention devices. Thus the author would like to name the device "tip-vortexring assisted stall suppression device".

57-66

A Suggested Mechanism of Significant Stall
Suppression Effects by Air Separator Devices in Axial
Flow Fans

67-75

Recent results are presented concerning the development of magnetofluidic
leakage-free rotating seals for vacuum and high pressure gases, evidencing
significant advantages compared to mechanical seals. The micro-pilot scale
production of various types of magnetizable sealing fluids is shortly reviewed,
Leakage-free Rotating Seal Systems with Magnetic
in particular the main steps of the chemical synthesis of magnetic nanofluids Rotating Seal, Magnetic Nanofluids, Magnetic
Tünde Borbáth, Doina Bica, Iosif Potencz, István Borbá
Nanofluids and Magnetic Composite Fluids Designed
and magnetic composite fluids with light hydrocarbon, mineral oil andComposite Fluids, Gas Valves, Testing Procedures,th, Tibor Boros, Ladislau Vékás
for Various Applications
synthetic oil carrier liquids. Design concepts and some constructive details of Magnetofluidic Applications
the magnetofluidic seals are discussed in order to obtain high sealing capacity.
Different types of magnetofluidic sealing systems and applications arereviewed. Testing procedures and equipment are presented, as well as thesealing capabilities of different types of magnetizable fluids.

76-83

This study highlights especially the mechanism of vortex cavitation occurrence
from the end of the suction duct in a double-suction volute pump and pump
oscillation which causes cavitation noise from the pump. In this study, full 3D
numerical simulations have been performed using a commercial code inside
Vortex Cavitation from Baffle Plate and Pump Vibratio Toshiyuki Sato, Takahide Nagahara, Kazuhiro Tanaka,
the pump from the inlet of suction duct to the outlet of delivery duct. The Vortex Cavitation, Cavitation Noise, Double-Suction
in a Double-Suction Volute Pump
Masaki Fuchiwaki, Fumio Shimizu, Akira Inouenumerical model is based on a combination of multiphase flow equations with Volute Pump, CFD, Pump Oscillation
the truncated version of the Rayleigh-Plesset model predicting thecomplicated growth and collapse process of cavity bubbles. The experimental
investigations have also been performed on the cavitating flow with flow
visualization to evaluate the numerical results.

85-96

Steady state computations are routinely used by design engineers to evaluate
and compare losses in hydraulic components. In the case of the draft tube
diffuser, however, experiments have shown that while a significant number ofoperating conditions can adequately be evaluated using steady statecomputations, a few operating conditions require unsteady simulations toaccurately evaluate losses. This paper presents a study that assesses thepredictive capacity of a combination of steady and unsteady RANS numericalHydraulic turbine, draft tube, steady flow simulation,
computations to predict draft tube losses over the complete range of
unsteady flow simulation
operation of a Francis turbine. For the prediction of the draft tube
performance using k-ε turbulence model, a methodology has been proposed
to average global performance indicators of steady flow computations such as
the pressure recovery factor over an adequate number of periods to obtaincorrect results. The methodology will be validated using two distinct flow
solvers, CFX and OpenFOAM, and through a systematic comparison withexperimental results obtained on the FLINDT model draft tube.

Steady and unsteady flow computation in an elbow
draft tube with experimental validation

Numerical Study of Passive Control with Slotted
97-103 Blading in Highly Loaded Compressor Cascade at Low
Mach Number

Vol. 4, No.
104-1131,
JanuaryMarch,
2011

A New Approach in Numerical Assessment of theCavitation Behaviour of Centrifugal Pumps

Nobuyuki Yamaguchi

Thi C. Vu, Christophe Devals, Ying Zhang, Bernd
Nennemann, François Guibault

Mdouki Ramzi, Gérard Bois, Gahmousse
Abderrahmane

Adrian Stuparu, Romeo Susan-Resiga, Liviu Eugen
Anton, Sebastian Muntean

With the aim to increase blade loadings and stable operating range in highly
loaded compressors, this article has been conducted to explore, through a
numerical parametric study, the potential of passive control using slottedbladings in cascade configurations. The objective of this numericalinvestigation is to analyze the influence of location, width and slope of theslots and therefore identify the optimal configuration. The approach is based
2D cascade, Highly loaded compressor, Separation,
on two dimensional cascade geometry, low speed regime, steady state andPassive control, Slotted blading, Low Mach number
turbulent RANS model. The results show the efficiency of this passive
technique to delay separation and enhance aerodynamic performances of thecompressor cascade. A maximum of 28.3% reduction in loss coefficient havebeen reached, the flow turning is increased with approximately 5° and highloading over a wide range of angle of attack have been obtained for the
optimized control parameter.
The paper presents a new method for the analysis of the cavitation behaviourof hydraulic turbomachines. This new method allows determining thecoefficient of the cavitation inception and the cavitation sensitivity of theturbomachines. We apply this method to study the cavitation behaviour of alarge storage pump. By plotting in semi-logarithmic coordinates the vapour cavitation inception, cavitation sensibility, pumping
volume versus the cavitation coefficient, we show that all numerical data
head drop, storage pumpcollapse in an exponential manner. By analysis of the slope of the curve
describing the evolution of the vapour volume against the cavitation
coefficient we determine the cavitation sensitivity of the pump for each
operating point.

2011
We have proposed a new approach based on energy gradient concept for the
study of flow instability and turbulent transition in parallel flows in ourprevious works. It was shown that the disturbance amplitude required for
turbulent transition is inversely proportional to Re, which is in agreement withthe experiments for imposed transverse disturbance. In present study, theenergy gradient theory is extended to the generalized curved flows which
114-132

Theory and Prediction of Turbulent Transition

Hua-Shu Dou, Boo Cheong Khoo

have much application in turbomachinery and other fluid delivery devices.
Within the frame of the new theory, basic theorems for flow instability in

Turbulent transition, Mechanism, Theory, Theorem,
Prediction

general cases are provided in details. Examples of applications of the theory
are given from our previous studies which show comparison of the theory withavailable experimental data. It is shown that excellent agreement has beenachieved for several configurations. Finally, various prediction methods for133-139140-149

Numerical Design and Performance Prediction of Low
Specific Speed Centrifugal Pump Impeller

Incipient Cavitation in a Bulb Turbine: Model Test and
CFD Calculation

Zhang Yongxue, Zhou Xin, Ji Zhongli, Jiang Cuiwei

Jörg Necker, Thomas Aschenbrenner

turbulent transition are reviewed and commented.
In this paper, Based on Two-dimensional Flow Theory, adopting quasiorthogonal method and point-by-point integration method to design the
impeller of the low specific speed centrifugal pump by code, and using RANS
(Reynolds Averaged N-S) Equation with a standard k-ε two-equation
turbulence model and log-law wall function to solve 3D turbulent flow field in Low Specific Speed, Centrifugal Pump impeller, Twothe impeller of the low specific speed pump. An analysis of the influences of dimensional Flow Theory, Numerical Design,
the blade profile on velocity distributions, pressure distributions and pump Performance Prediction
performance and the investigation of the flow regulation pattern in the
impeller of the centrifugal pump are presented. And the result shows that thismethod can be used as a new way in low speed centrifugal pump impeller
design.
For a certain operating point of a horizontal shaft bulb turbine (i.e. volume
flow, net head, blade angle, guide vane angle) the efficiency for differentpressure levels (i.e. different Thoma-coefficient σ) is calculated using acommercial Computational Fluid Dynamics (CFD-)-code including two-phaseflow and a cavitation model. The results are compared with experimental
results achieved at a closed loop test rig for model turbines. The comparison
Bulb turbines, multi-phase cfd, incipient cavitation,of the experimentally and numerically obtained efficiency and the visualadmissible cavitation
impression of the cavitation show a good agreement. Especially the drop in
efficiency is calculated with satisfying accuracy. This drop in efficiency in
combination with the visual impression is of high practical importance since it
contributes to determine the admissible cavitation in a bulb-turbine. It is seenthat the incipient cavitation in Kaplan type turbines has no major importancein determing this admissible amount of cavitation.

This study focuses on the Achard turbine, a vertical axis, cross-flow, marine
current turbine module. Similar modules can be superposed to form towers. A
marine or river hydropower farm consists of a cluster of barges, eachgathering several parallel rows of towers, running in stabilized current. Twodimensional numerical modelling is performed in a horizontal cross-section of
all towers, using FLUENT and COMSOL Multiphysics. Numerical models
Achard turbine, cross-flow current turbine,
Efficiency of Marine Hydropower Farms Consisting of Andrei-Mugur Georgescu, Sanda-Carmen Georgescu,
validation with experimental results is performed through the velocity
150-160
hydropower farm, farm efficiency, force coefficient,
Multiple Vertical Axis Cross-Flow Turbines
Costin Ioan Cosoiu, Nicolae Alboiu
distribution, depicted by Acoustic Doppler Velocimetry, in the wake of thepower coefficient
middle turbine within a farm model. As long as the numerical flow in the wakefits the experiments, the numerical results for the power coefficient (turbine
efficiency) are trustworthy. The overall farm efficiency, with respect to thespatial arrangement of the towers, was depicted by 2D modelling of theunsteady flow inside the farm, using COMSOL Multiphysics. Rows ofoverlapping parallel towers ensure the increase of global efficiency of the farm.

161-171

Steady-state Capabilities for Hydroturbines with
OpenFOAM

Maryse Page, Martin Beaudoin, Anne-Marie Giroux

The availability of a high quality open source CFD simulation platform like
OpenFOAM offers new R&D opportunities by providing direct access tomodels and solver implementation details. Efforts have been made by HydroQuébec to adapt OpenFOAM to hydroturbines for the development of steadyOpenFOAM, hydroturbine, GGI interface, mixing plane
state capabilities. This paper describes the developments that have been madeinterface, multiple frames of reference
to implement new turbomachinery related capabilities: multiple frames ofreference solver, domain coupling interfaces (GGI, cyclicGGI and mixing plane)and specialized boundary conditions. Practical use of the new turbomachinery
capabilities are demonstrated for the analysis of a 195-MW Francis turbine.

172-178

Optimization of Vane Diffuser in a Mixed-Flow Pump
for High Efficiency Design

Jin-Hyuk Kim, Kwang-Yong Kim

179-190

Experimental Investigations on Upper Part Load
Vortex Rope Pressure Fluctuations in Francis Turbine
Draft Tube

Christophe Nicolet, Amirreza Zobeiri, Pierre
Maruzewski, François Avellan

191-198

Cavitation in a Shaft-less Double Suction Centrifugal
Miniature Pump

Baotang Zhuang, Xianwu Luo, Lei Zhu, Xin Wang,
Hongyuan Xu

This paper presents an optimization procedure for high-efficiency design of amixed-flow pump. Optimization techniques based on a weighted-averagesurrogate model are used to optimize a vane diffuser of a mixed-flow pump.
Validation of the numerical results is performed through experimental data forhead, power and efficiency. Three-level full factorial design is used to generatenine design points within the design space. Three-dimensional Reynoldsaveraged Navier-Stokes equations with the shear stress transport turbulence Mixed-flow pump, Impeller, Vane diffuser, Efficiency,model are discretized by using finite volume approximation and solved on Optimization, Weighted-average surrogate modelhexahedral grids to evaluate the efficiency as the objective function. In orderto reduce pressure loss in the vane diffuser, two variables defining the straight
vane length ratio and the diffusion area ratio are selected as design variablesin the present optimization. As the results of the design optimization, theefficiency at the design flow coefficient is improved by 7.05% and the offdesign efficiencies are also improved in comparison with the reference design.
The swirling flow developing in Francis turbine draft tube under part load
operation leads to pressure fluctuations usually in the range of 0.2 to 0.4 times
the runner rotational frequency resulting from the so-called vortex breakdown.
For low cavitation number, the flow features a cavitation vortex rope animatedwith precession motion. Under given conditions, these pressure fluctuations
may lead to undesirable pressure fluctuations in the entire hydraulic system
and also produce active power oscillations. For the upper part load range,
between 0.7 and 0.85 times the best efficiency discharge, pressure fluctuations
may appear in a higher frequency range of 2 to 4 times the runner rotational
speed and feature modulations with vortex rope precession. It has been
pointed out that for this particular operating point, the vortex rope features
elliptical cross section and is animated of a self-rotation. This paper presents
Francis turbine, cavitating vortex rope, High Speedan experimental investigation focusing on this peculiar phenomenon, defined
Camera visualization, pressure fluctuations
as the upper part load vortex rope. The experimental investigation is carriedout on a high specific speed Francis turbine scale model installed on a test rigof the EPFL Laboratory for Hydraulic Machines. The selected operating point
corresponds to a discharge of 0.83 times the best efficiency discharge.
Observations of the cavitation vortex carried out with high speed camera havebeen recorded and synchronized with pressure fluctuations measurements atthe draft tube cone. First, the vortex rope self rotation frequency is evidenced
and the related frequency is deduced. Then, the influence of the sigma
cavitation number on vortex rope shape and pressure fluctuations ispresented. The waterfall diagram of the pressure fluctuations evidences
resonance effects with the hydraulic circuit. The influence of outlet bubble
cavitation and air injection is also investigated for low cavitation number. The
Based on the consideration that the cavitation would affect the operation
stability of miniature pumps, the 3-D turbulent cavitating flow in a test pump
was simulated by using a mixed cavitation model and k-ω SST turbulencemodel. In order to investigate the influence of inlet geometry parameters on
the cavitation performance of the miniature pump, two more impellers aredesigned for comparison. Based on the results, the following conclusions are
drawn: 1) Cavitation performance of the double suction shaft-less miniature
double suction, shaft-less, miniature pump, cavitation,
pump having different impeller is equivalent to the centrifugal pump having
numerical simulation
ordinary size, though the flow passage at impeller inlet is small; 2) The
miniature pump having radial impeller can produce much higher pump head,but lower cavitation performance than that having the impeller based on theconventional design method; 3) It is believed that by applying the double
suction design, the miniature pump achieved relatively uniform flow pattern
upstream the impeller inlet, which is favorable for improving cavitation
performance.

This work presents numerical results, using OpenFOAM, of the flow in the swirl
flow generator test rig developed at Politehnica University of Timisoara,
Romania. The work shows results computed by solving the unsteady Reynolds
Averaged Navier Stokes equations. The unsteady method couples the rotating
and stationary parts using a sliding grid interface based on a GGI formulation.
Turbulence is modeled using the standard k-ε model, and block structured
199-208

Unsteady Simulations of the Flow in a Swirl
Generator, Using OpenFOAM

Olivier Petit, Alin I. Bosioc, Håkan Nilsson, Sebastian
Muntean, Romeo F. Susan-Resiga

wall function ICEM-Hexa meshes are used. The numerical results are validated
Swirl generator, OpenFOAM, CFD, Validation, Runner,
against experimental LDV results, and against design velocity profiles. The
Draft tube, Rotor-Stator Interaction
investigation shows that OpenFOAM gives results that are comparable to theexperimental and design profiles. The unsteady pressure fluctuations at four
different positions in the draft tube is recorded. A Fourier analysis of thenumerical results is compared whit that of the experimental values. The
amplitude and frequency predicted by the numerical simulation arecomparable to those given by the experimental results, though slightly overestimated.
The flow upstream of a centrifugal pump impeller has been investigated by

209-216

Investigation on the Flow Field Upstream of aCentrifugal Pump Impeller

Page

Title

217-222223-228

The Effect of Casing Geometry on Rotordynamic Fluid
Forces on a Closed Type Centrifugal Impeller inWhirling Motion

Study on the Performance Characteristics ofCentrifugal Pump with Drag-reducing Surfactant
Additives

both experimental test and numerical simulation. For experimental study, theflow field at four sections in the pump suction is measured by using PIV
method. For calculation, the three dimensional turbulent flow for the full flow
passage of the pump is simulated based on RANS equations combined with
Yao Zhang, Xianwu Luo, Yunchi Yi, Baotang Zhuang, RNG k-ε turbulence model. From those results, it is noted that at both design centrifugal pump, flow upstream impeller inlet, PIV,
Hongyuan Xu
load and quarter load condition, the pre-swirl flow whose direction is the same numerical simulation
as the impeller rotation exists at all four sections in suction pipe of the pump,
and at each section, the pre-swirl velocity becomes obviously larger at higher
rotational speed. It is also indicated that at quarter load condition, the lowpressure region at suction surface of the vane is large because of theunfavorable flow upstream of the pump impeller.
Author

Abstract

Keywords

Julien Richert, Yumeto Nishiyama, Shinichiro Hata,
Hironori Horiguchi, Yoshinobu Tsujimoto

The rotordynamic fluid forces acting on a closed type impeller in whirling
motion were measured and the influence of the clearance geometry on thestability of the impeller was examined. At small positive whirling speed, therotordynamic forces acted as destabilizing forces for all casings. A small
clearance between the shroud of the impeller and the casing caused large
fluid force, but did not change the destabilizing region. Radial grooves in the Pump, Rotordynamic Fluid Force, Whirling Motion,clearance were effective for reducing the fluid forces and destabilizing region Unsteady Phenomenon
due to the reduction of the circumferential velocity without the deteriorationof the pump performance. A rotating phenomenon like a rotating stall of theimpeller occurred at low flow rate and the resonance between it and thewhirling motion led to a sudden increase in force at the whirling speed ratio of
0.7.

Lu Wang, Feng-Chen Li, Yong Dong, Wei-Hua Cai,
Wen-Tao Su

The performance characteristics of centrifugal pump were measured
experimentally when running with tap water and drag-reducing surfactant(Octadecyl dimethyl amine oxide (OB-8)) solutions. Tests have been performedon five cases of surfactant solutions with different concentrations (0ppm (tapwater), 200ppm, 500ppm, 900ppm and 1500ppm) and four different rotating
speeds of pump (1500rpm, 2000rpm, 2500rpm and 2900rpm). Compared with centrifugal pump, surfactant solutions, drag reduction
tap water case, the experimental results show that the total pump heads forsurfactant solution cases are higher. And the pump efficiency with surfactant
solutions also increases, but the shaft power for surfactant solutions cases
decreases compared to t hat for tap water. There exists an optimal
temperature for surfactant solutions, which maximizes the pump efficiency.

For Lift-type Vertical Axis Wind Turbine (VAWT), it is difficult to evaluate theperformance through the scale-model wind tunnel tests, because of the scaleeffect relating to Reynolds number. However, it is beneficial to figure out thecritical value of Reynolds number or minimum size of the Lift-type VAWT,
Influence of Reynolds Number and Scale on
Tadakazu Tanino, Shinichiro Nakao, Takeshi Miyaguni, when designing this type of micro wind turbine. Therefore, in this study, the Vertical Axis Wind Turbine, Wind tunnel, Reynolds
229-234 Performance Evaluation of Lift-type Vertical Axis Wind
Kazunobu Takahashi
performance of several scale-models of Lift-type VAWT (Reynolds number : number, Performance, Scale effectTurbine by Scale-model Wind Tunnel Tests
1.5x104 to 4.6x104) was investigated. As a result, the Reynolds number effectdepends on the blade chord rather than the inlet velocity. In addition, there
was a transition point of the Reynolds number to change the dominant driving
force from Drag to Lift.
An application of contra-rotating rotors, in which a rear rotor is in tandemwith a front one and these rotors rotate in the opposite direction each other,has been proposed against a demand for developing higher specific speed
axial flow pump. One prototype rotors, which we have designed with aconventional method, has given the positive slope of head characteristic curveInternal Flow and Limiting Streamlines Observations
Satoshi Watanabe, Shimpei Momosaki, Satoshi Usami,
especially in the rear rotor. It is necessary to understand the internal flow
Axial flow pump, Contra-rotating rotors, Partial flow
235-242 of Contra-Rotating Axial Flow Pump at Partial Flow
Akinori Furukawa
behavior in the rear rotor to establish the design guideline for achievingrate, LDV, Limiting streamlines
Ratehigher and more reliable performance. In the present study, we carried out theexperimental investigations of the internal flow field of the rear rotor,
especially at the partial flow rate, by Laser Doppler Velocimetry (LDV) for themain flow and the limiting streamlines observation on rotor surfaces for theboundary layer flows.
In the present paper, we focus on the flow computation of a low head
Propeller turbine at a wide range of design and off-design operating
conditions. First, we will present the results on the efficiency hill chart
prediction of the Propeller turbine and discuss the consequences of using
non-homologous blade geometries for the CFD simulation. The flow
Flow simulation and efficiency hill chart prediction for Thi Vu, Marcel Koller, Maxime Gauthier, Claire Deschê characteristics of the entire turbine will be also investigated and compared Propeller Turbine, CFD, Flow Simulation, Performance243-254
a Propeller turbineneswith experimental data at different measurement planes. Two operating
prediction, Non-homologous geometry, Draft Tube
conditions are selected, the first one at the best efficiency point and thesecond one at part load condition. At the same time, for the same selected
operating points, the numerical results for the entire turbine simulation will becompared with flow simulation with our standard stage calculation approach
which includes only guide vane, runner and draft tube geometries.

Vol. 4, No.
2, AprilJune, 2011255-261

Effects of the Air Volume in the Air Chamber on the
Performance of Water Hammer Pump System

Sumio Saito, Masaaki Takahashi, Yoshimi Nagata

Recently, as global-scale problems, such as global warming and energy
depletion, have attracted attention, the importance of future environmental
preservation has been emphasized worldwide, and various measures havebeen proposed and implemented. This study focuses on water hammer pumps
that can effectively use the water hammer phenomenon and allow fluid
transport without drive sources, such as electric motors. An understanding ofoperating conditions of water hammer pumps and an evaluation of their basic
hydrodynamic characteristics are significant for determining whether they canbe widely used as an energy-saving device in the future. However,
Water Hammer Pump, Fluid Transients, Pump
conventional studies have not described the pump performance in terms of
Performance, Pressure Fluctuation, Flow Visualization
pump head and flow rate, common measures indicating the performance ofpumps. As a first stage for the understanding of water hammer pump
performance in comparison to the characteristics of typical turbo pumps, theprevious study focused on understanding the basic hydrodynamic
characteristics of water hammer pumps and experimentally examined how thehydrodynamic characteristics were affected by the inner diameters of the drive
and lift pipes and the angle of the drive pipe. This paper suggests the effect of
the air volume in the air chamber that affects the hydrodynamic characteristics
and operating conditions of the water hammer pump.

Experimental and numerical investigations were conducted for an internal flowin an axial flow stator of a diagonal flow fan. A corner separation near the hub
surface and the suction surface of a stator blade was focused on, and further,three-dimensional vortices in separated flow were investigated by the

Vortices within a Three-Dimensional Separation in an
262-270
Axial Flow Stator of a Diagonal Flow Fan

Yoichi Kinoue, Norimasa Shiomi, Toshiaki Setoguchi

numerical analysis. At low flow rate of 80% of the design flow rate, a cornerseparation of the stator between the suction surface and the hub surface canDiagonal flow fan, Axial flow stator, Internal flow,
be found in both experimental and calculated results. Separation vortices are
Corner separation, Five-hole probe survey, CFD
observed in the limiting streamline patterns both on the blade suction and on
the hub surfaces at 80% of the design flow rate in the calculated results. It
also can be observed in the streamline pattern that both vortices from theblade suction surface and from the hub surface keep vortex structures up to
far locations from these wall surfaces. An attempt to explain the vortices withina three-dimensional separation is introduced by using vortex filaments.
The mathematical modelling of screw compressor processes and its

271-288

Review of Mathematical Models in Performance
Calculation of Screw Compressors

implementation in their design began about 30 years ago with the publicationof several pioneering papers on this topic, mainly at Purdue Compressor
Conferences. This led to the gradual introduction of computer aided design,
which, in turn, resulted in huge improvements in these machines, especially in
oil-flooded air compressors, where the market is very competitive. A review ofprogress in such methods is presented in this paper together with theirapplication in successful compressor designs. As a result of their introduction,even small details are now considered significant in efforts to improve
Nikola Stosic, Ian K. Smith, Ahmed Kovacevic, Elvedin
performance and reduce costs. Despite this, there are still possibilities toScrew Compressor, Mathematical Model, Performance
Mujic
introduce new methods and procedures for improved rotor profiles, design Calculation
optimisation for each specified duty and specialized compressor design, all ofwhich can lead to a better product and new areas of application. A review ofmethods and procedures which lead to modern screw compressor practice ispresented in this paper. This paper is intended to give a cross section throughactivities being done in mathematical modelling of screw compressor process
through last five decades. It is expected to serve as a basis for further
contributions in the area and as a challenge to the forthcoming generations ofscientists and engineers to concentrate their efforts in finding future and more
extended approaches and submit their contributions.

289-306

Vibration Behavior and Dynamic Stress of Runners of
Very High Head Reversible Pump-turbines

Hiroshi Tanaka

Page

Title

AuthorIn the development of very high head pumped storage projects, one of thecritical problems is the strength of pumpturbine runners. Data obtained bystress measurements of high head pump-turbine runners indicated thatdynamic stress due to the vibration of runner might be detrimental, possibly
to cause fatigue failure, if the runner were designed without proper
Vibration behavior, Dynamic stress, Hydraulicconsideration on its dynamic behaviour. Numerous field stress measurements
excitation force, Vibration mode, Prototype headof runners and model tests conducted with hydrodynamic similarity revealed
model test
that the hydraulic excitation force developed by the interference of rotating
runner blades with guide vane wakes sometimes would induce such heavy
vibration of runner. Theoretical and experimental investigations on both thehydraulic excitation force and the natural frequencies of runner have been
conducted to explore this forced vibration problem.
Abstract

Keywords

In order to clarify the features of tip leakage vortex near blade tip region in a
half-ducted axial fan with large bellmouth, the experimental investigation was
carried out using a 2-dimensional LDV system. Three sizes of tip clearance (TC)were tested: those sizes were 1mm (0.55% of blade chord length at blade tip),
2mm (1.11% of blade chord length at blade tip) and 4mm (2.22% of blade
chord length at blade tip), and those were shown as TC=1mm, TC=2mm and
TC=4mm, respectively. Fan characteristic tests and the velocity fieldmeasurements were done for each TC. Pressure - flow-rate characteristics andVortex Features in a Half-ducted Axial Fan with Large Norimasa Shiomi, Yoichi Kinoue, Toshiaki Setoguchi, two-dimensional velocity vector maps were shown. The vortex trace and the Tip leakage vortex, Tip clearance, Ventilation fan, LDV
307-316
Bellmouth (Effect of Tip Clearance)
Kenji Kaneko
vortex intensity distribution were also illustrated. As a result, a large difference measurementon the pressure - flow-rate characteristics did not exist for three tip clearance
sizes. In case of TC=4mm, the tip leakage vortex was outflow to downstreamof rotor was not confirmed at the small and reference flow-rate conditions.
Only at the large flow-rate condition, its outflow to downstream of rotor
existed. In case of TC=2mm, overall vortex behaviors were almost the sameones in case of TC=4mm. However, the vortex trace inclined toward moretangential direction. In case of TC=1mm, the clear vortex was not observed for
all flow-rate conditions.
Mini centrifugal pumps having a diameter smaller than 100mm are employedin many fields; automobile radiator pump, ventricular assist pump, coolingpump for electric devices and so on. Further, the needs for mini centrifugal
pumps would become larger with the increase of the application of it forelectrical machines. It is desirable that the mini centrifugal pump design be as
simple as possible as precise manufacturing is required. But the design method
for the mini centrifugal pump is not established because the internal flow
condition for these small-sized fluid machines is not clarified and conventional
theory is not suitable for small-sized pumps. Therefore, we started research on
the mini centrifugal pump for the purpose of development of highperformance mini centrifugal pumps with simple structure. Three types ofInfluence of Blade Outlet Angle and Blade Thickness
rotors with different outlet angles are prepared for an experiment. The
Mini centrifugal pump, Performance, Internal flow
317-323 on Performance and Internal Flow Conditions of Mini
Toru Shigemitsu, Junichiro Fukutomi, Kensuke Kaji
performance tests are conducted with these rotors in order to investigate thecondition, Blade outlet angle, Blade thickness
Centrifugal Pump
effect of the outlet angle on performance and internal flow condition of mini
centrifugal pumps. In addition to that, the blade thickness is changed because
blockage effect in the mini centrifugal pump becomes relatively larger thanthat of conventional pumps. On the other hand, a three dimensional steadynumerical flow analysis is conducted with the commercial code (ANSYS-Fluent)
to investigate the internal flow condition. It is clarified from the experimental
results that head of the mini centrifugal pump increases according to theincrease of the blade outlet angle and the decrease of the blade thickness. In
the present paper, the performance of the mini centrifugal pump is shown andthe internal flow condition is clarified with the results of the experiment andthe numerical flow analysis. Furthermore, the effects of the blade outlet angle
and the blade thickness on the performance are investigated and the internal
Phase resonance in a centrifugal compressor was experimentally observed andsimulated with a commercial CFD code. It was found that pressure fluctuation
Yumeto Nishiyama, Takayuki Suzuki, Koichi Yonezawa, at the volute outlet becomes the maximum when the rotational speed of the Phase resonance, Rotor-stator interaction, Centrifugal
324-333
Phase Resonance in a Centrifugal Compressor
Hiroshi Tanaka, Peter Doerfler, Yoshinobu Tsujimoto modes caused by the rotor-stator interaction agrees with the sound velocity. A compressor, Volute, Numerical analysis
simple one-dimensional theory is presented to explain the phase resonance inturbomachinery.

Vol. 4, No.
3, JulySeptember, 2011

Turbo-pumps have weak points, such as the pumping operation is unstable on
the positive slope of the head curve and/or the cavitation occurs at the low
suction head. To improve simultaneously both weak points, the first author
invented the unique pumping unit composed of the tandem impellers and thepeculiar motor with the double rotational armatures. The front and the rear
impellers are driven by the inner and the outer armatures of the motor,
respectively. Both impeller speeds are automatically and smartly adjusted in
response to the pumping discharge, while the rotational torques between bothVol. 4, No.
3, JulySeptember, 2011

334-340

Counter-Rotating Type Pumping Unit (Impeller
Speeds in Smart Control)

Toshiaki Kanemoto, Keiichi Komaki, Masaaki
Katayama, Makoto Fujimura341-348

Computational Fluid Dynamics Modeling Studies on
Bacterial Flagellar Motion

Manickam Siva Kumar, Pichai Philominathan349-359

Unsteady Analysis of Impeller-Volute Interaction inCentrifugal Pump

Kean Wee Cheah, Thong See Lee, Sonny H. Winoto

Page

Title

Author360-366367-374

Prediction of Cascade Performance of Circular-Arc
Blades with CFD

Effects of the Geometry of Components Attached to
the Drain Valve on the Performance of Water
Hammer Pumps

Vol. 4, No.
4,
OctoberComputational Study of the Magnetically Suspended
December,
Centrifugal Blood Pump (2nd Report: Pressure
2011375-386
Fluctuation and Stability of Impeller Rotation for
Different Volute Shapes)

impellers/armatures are counter-balanced. Such speeds contribute to suppress
successfully not only the unstable operation at the low discharge but also thecavitation at the high discharge, as verified with the axial flow type pumping
unit in the previous paper. Continuously, this paper investigates experimentallycounter-rotation, tandem impellers, pump, armature,
the effects of the tandem impeller profiles on the pump performances and thesmart control, performance, rotational speed
rotational speeds against the discharge, using the impellers whose loads are
low and/or high at the normal discharge. The worthy remarks are that (a) the
unstable operation is suppressed as expected and the shut off power isscarcely large in the smart control, (b) the blade profile contributes todetermine the discharge giving the maximum/minimum rotational speed
where the reverse flow may incipiently appears at the front impeller inlet, (c)the tandem impeller profiles scarcely affect the rotational speeds, while theloads of the front and the rear impellers are same, but (d) the impeller withthe low load must run faster and the impeller with the high load must run
slower at the same discharge to take the same rotational torque, and (e) thereverse flow at the inlet and the swirling velocity component at the outlet ofthe front impeller with the high load require making the rotational speed of
The study of bacterial flagellar swimming motion remains an interesting andchallenging research subject in the fields of hydrodynamics and biolocomotion. This swimming motion is characterized by very low Reynolds
numbers, which is unique and time reversible. In particular, the effect ofrotation of helical flagella of bacterium on swimming motion requires detailed
multi-disciplinary analysis. Clear understanding of such swimming motion will
not only be beneficial for biologists but also to engineers interested indeveloping nanorobots mimicking bacterial swimming. In this paper,
Flagellar hydrodynamics, helical swimming motion,
computational fluid dynamics (CFD) simulation of a three dimensional single
low Reynolds number, computational fluid dynamics
flagellated bacteria has been developed and the fluid flow around theflagellum is investigated. CFD-based modeling studies were conducted to findthe variables that affect the forward thrust experienced by the swimming
bacterium. It is found that the propulsive force increases with increase inrotational velocity of flagellum and viscosity of surrounding fluid. It is also
deduced from the study that the forward force depends on the geometry ofhelical flagella (directly proportional to square of the helical radius andinversely proportional to pitch).

An unsteady numerical analysis has been carried out to study the strong
impeller volute interaction of a centrifugal pump with six backward swept
blades shrouded impeller. The numerical analysis is done by solving the threedimensional Reynolds Averaged Navier-Stokes codes with standard k-ε twoequations turbulence model and wall regions are modeled with a scalable loglaw wall function. The flow within the impeller passage is very smooth andfollowing the curvature of the blade in stream-wise direction. However, theanalysis shows that there is a recirculation zone near the leading edge even at centrifugal pump, impeller, spiraling vortex flow,
design point. When the flow is discharged into volute casing circumferentially pressure fluctuationfrom the impeller outlet, the high velocity flow is severely distorted andformed a spiraling vortex flow within the volute casing. A spatial and temporalwake flow core development is captured dynamically and shows how the wakecore diffuses. Near volute tongue region, the impeller/volute tongue strong
interaction is observed based on the periodically fluctuating pressure at outlet.
The results of existing analysis also proved that the pressure fluctuation
periodically is due to the position of impeller blade relative to tongue.
Abstract

Keywords

Masami Suzuki, Toshiaki Setoguchi, Kenji Kaneko

Thin circular-arc blade is often used as a guide vane, a deflecting vane, or arotating blade of low pressure axial-flow turbomachine because of its easy
manufacture. Ordinary design of the blade elements of these machines is doneby use of the carpet diagrams for a cascade of circular-arc blades. However,
the application of the carpet diagrams is limited to relatively low cambered
blade operating under optimum inlet flow conditions. In order to extend theapplicable range, additional design data is necessary. Computational fluid
Circular-arc blades, Cascade, Guide Vane, Potential
dynamics (CFD) is a promising method to get these data. In this paper, two- Flow, CFD
dimensonal cascade performances of circular-arc blade are widely analyzed
with CFD. The results have been compared with the results of experiment andpotential theory, and useful information has been obtained. Turning angle andtotal pressure loss coefficients are satisfactorily predicted for lowly cambered
blade. For high camber angle of 67°, the CFD results agree with experiment for
the angle of attack less than that for shockless inlet condition.

Sumio Saito, Masaaki Takahashi, Yoshimi Nagata,
Keita Dejima

Water hammer pumps can effectively use the water hammer phenomenon in
long-distance pipeline networks that include pumps and allow fluid transport
without drive sources, such as electric motors. The results of experiments thatexamined the effect of the geometric form of water hammer pumps byconsidering their major dimensions have been reported. In addition, a paper
has also been published analyzing the water hammer phenomenon
numerically by using the characteristic curve method for comparison withexperimental results. However, these conventional studies have not fully
evaluated the pump performance in terms of pump head and flow rate,common measures indicating the performance of pumps. Therefore, as a firststage for the understanding of water hammer pump performance inWater Hammer Pump, Fluid Transients, Pumpcomparison with the characteristics of typical turbo pumps, the previous paper
Performance, Pressure Fluctuation, Flow Visualization
experimentally examined how the hydrodynamic characteristics were affectedby the inner diameter ratio of the drive and lifting pipes, the form of the airchamber, and the angle of the drive pipe. To understand the behavior of thecomponents attached to the valve chamber and the air chamber that affects
the performance of water hammer pumps, the previous study also determined
the relationship between the water hammer pump performance and temporalchanges in valve chamber and air chamber pressures according to the airchamber capacity. For the geometry of components attached to the drain
valve, which is another major component of water hammer pumps, this study
experimentally examines how the water hammer pump performance is affectedby the length of the spring and the angle of the drain pipe.

Yoshifumi Ogami, Daisuke Matsuoka, Masaaki Horie

The turbo-type blood pump studied in this paper has an impeller that ismagnetically suspended in a double volute casing. The impeller rotates withminimal fluctuations caused by fluid and magnetic forces. In order to improvestability of the rotating impeller and to facilitate long-term use, a careful
investigation of the pressure fluctuations and of the fluid force acting on the Computational Fluid Dynamics, Centrifugal Blood
impeller is necessary. For this purpose, two models of the pump with different Pump, Pressure Fluctuation, Stability of Impeller
volute cross-sectional area are designed and studied with computational fluid Rotation, Numerical Analysis
dynamics software. The results show that the fluid force varies with the flowrate and shape of the volute, that the fluctuations of fluid force decrease withincreasing flow rate and that the vibratory movement of the impeller is more
efficiently suppressed in a narrow volute.

Single-blade centrifugal pumps are widely used as sewage pumps. However,
the impeller of a single-blade pump is subjected to strong radial thrust during
pump operation because of the geometrical axial asymmetry of the impeller.
Therefore, to improve pump reliability, it is necessary to quantitatively

387-395

Radial Thrust of Single-Blade Centrifugal Pump

Yasuyuki Nishi, Junichiro Fukutomi, Ryota Fujiwara

understand radial thrust and elucidate the behavior and mechanism of thrustgenerating. This study investigates the radial thrust acting up on a singleblade centrifugal impeller by conducting experiments and CFD analysis. The
results show that the fluctuating component of radial thrust increases as theflow rate deviates from the design flow rate to low or high value. Radial thrust
was modeled by a combination of three components, inertia, momentum, and Turbomachinery, Centrifugal Pump, Sewage pump,pressure by applying an unsteady conservation of momentum to the impeller. Single-Blade, Radial Thrust, CFD
The sum of these components agrees with the radial thrust calculated byintegrating the pressure and the shearing stress on the impeller surface. The
behavior of each component was shown, and the effects of each component
on radial thrust were clarified. The pressure component has the greatest effecton the time-averaged value and the fluctuating component of radial thrust.
The time-averaged value of the inertia component is nearly 0, irrespective of
the change in the flow rate. However, its fluctuating component has amagnitude nearly comparable with the pressure component at a low flow rateand slightly decreased with the increase in flow rate.

396-409

Mathematical Model for the Effect of Blade Friction
on the Performance of Pelton Turbine

Iresha Udayangani Atthanayake, Thusitha
Sugathapala, Rathna Fernando

Page

Title

Author

1-9

10-17

Numerical Analysis of the Influence of Acceleration on
Cavitation Instabilities that arise in Cascade

Oxygen Transfer Characteristics of an Ejector Aeration
SystemYuka Iga, Tasuku Konno

30-37

CFD Analysis of Cavitation Phenomena in Mixed-Flow
Pump

Experimental Study on Adjustment of Inlet Nozzle
Section to Flow Rate Variation for Darrieus-type
Hydro-Turbine

Abstract

Keywords

In the turbopump inducer of a liquid propellant rocket engine, cavitation isaffected by acceleration that occurs during an actual launch sequence. Sincecavitation instabilities such as rotating cavitations and cavitation surges aresuppressed during launch, it is difficult to obtain data on the influence ofacceleration on cavitation instabilities. Therefore, as a fundamental
investigation, in the present study, a three-blade cyclic cascade is simulated
numerically in order to investigate the influence of acceleration on timeaveraged and unsteady characteristics of cavitation that arise in cascade.
Several cases of acceleration in the axial direction of the cascade, including
accelerations in the upstream and downstream directions, are considered. The
numerical results reveal that cavity volume is suppressed in low cavitation
number condition and cavitation performance increases as a result of highCavitation Instability, Cascade, Acceleration,
acceleration in the axial-downstream direction, also, the inverse tendency is
Homogeneous Model, CFD
observed in the axial-upstream acceleration. Then, the regions in which theindividual cavitation instabilities occur shift slightly to a low-cavitation-number
region as the acceleration increases downstream. In addition, in a downstream
acceleration field, neither sub-synchronous rotating cavitation nor rotatingstall cavitation are observed. On the other hand, rotating-stall cavitation
occurs in a relatively higher-cavitationnumber region in an upstream
acceleration field. Then, acceleration downstream is robust against cavitation
instabilities, whereas cavitation instabilities easily occur in the case ofacceleration upstream. Additionally, comparison with the Froude number
under the actual launch conditions of a Japanese liquid propellant rocket
reveals that the cavitation performance will not be affected by the acceleration
under the current launch conditions.

Hei-Cheon Yang, Sang-Kyoo ParkThe objective of this study was to investigate the oxygen transfer
characteristics of an ejector aeration system. In order to evaluate the oxygen
transfer performance of the ejector aeration system, a comparative experiment
was conducted on a conventional blower aeration system. The effect ofentrained air flow rate and aerating water temperature on the oxygen transfer
efficiency was investigated. The dissolved oxygen concentration increased with
Ejector aeration system, Dissolved oxygen, Oxygen
increasing entrained air flow rate, but decreased with increasing aerating watermass transfer, Aerating water, Entrained airtemperature for two aeration systems. The volumetric mass transfer coefficientincreased with increasing entrained air flow rate and with increasing aeratingwater temperature for both aeration systems. The average mass transfer
coefficient for the ejector aeration system was about 20% and 42% higher
than that of the blower aeration system within the experimental range ofentrained air flow rates and aerating water temperatures.

Milan Sedlar, Oldrich Sputa, Martin KomarekThis paper deals with the CFD analysis of cavitating flow in the mixed-flow
pump with the specific speed of 1.64 which suffers from a high level of noiseand vibrations close to the optimal flow coefficient. The ANSYS CFX package
has been used to solve URANS equations together with the Rayleigh-Plessetmodel and the SST-SAS turbulence model has been employed to capture
mixed-flow pump, cavitation, CFD, unsteady flow
highly unsteady phenomena inside the pump. The CFD analysis has provided aphenomena
good picture of the cavitation structures inside the pump and their dynamics
for a wide range of flow coefficients and NPSH values. Cavitation instabilities
were detected at 70% of the optimal flow coefficient close to the NPSH3 value(NPSH3 is the net positive suction head required for the 3% drop of the totalhead of the pump).

Vol. 5, No.
1,
JanuaryMarch,
2012

18-29

Water turbines have been used in electricity generation for well over a century.
Hydroelectricity now supplies 19% of world electricity. Many hydro power
plants are operated with Pelton turbines, which is an impulse turbine. The
main reasons for using impulse turbines are that they are very simple andrelatively cheap. As the stream flow varies, water flow to the turbine can beeasily controlled by changing the number of nozzles or by using adjustable
Pelton Turbine, Blade friction, Direct friction, Indirect
nozzles. Scientific investigation and design of turbines saw rapid advancement
friction
during last century. Most of the research that had been done on turbines werefocused on improving the performance with particular reference to turbine
components such as shaft seals, speed increasers and bearings. There is notmuch information available on effects of blade friction on the performance ofturbine. The main focus in this paper is to analyze the performance of Peltonturbine particularly with respect to their blade friction.

A two dimensional Darrieus-type turbine has been proposed for thehydropower utilization of extra-low head less than 2m. In a practical use of
Darrieus-type hydro-turbine, head and flow rate may be varied temporally andseasonally. Considering that the cost advantage is required for the low headhydro turbine system, the Darrieus turbine should be operated with highSatoshi Watanabe, Kai Shimokawa, Akinori Furukawa,Hydro-turbine, Darrieus-type runner, Inlet nozzle,
efficiency in the wider range of flow rate possibly by using an additional
Kusuo Okuma, Daisuke Matsushita
Partial inlet flow, Self-starting characteristics
device with simpler mechanism. In the present paper, an adjustment of inlet
nozzle section by lowering the inlet nozzle height is proposed to obtain thepreferable inlet velocity in low flow rate conditions. Effects of resulting
spanwise partial inlet flow are investigated. Finally, an effective modification of
inlet nozzle height over flow rate variation is shown.

38-48

Performance Prediction of Centrifugal Compressor
Based on Performance Test, Similarity Conversion and
CFD Simulation

Changyun Zhu, Guoliang Qin

Page

Title

AuthorOne centrifugal compressor is applied for refrigeration and its working
substance is R134a. The operating points obtained by using similar conversion
at different rotation speeds are compared with the numerical results. They
keep consistent with each other while the rotation speeds are lower, but theerror between them will become large with the increasing of the rotation
speed. Then the operating points are obtained when the working substance is
air by using two similar conversion methods separately. Based on the
Performance Prediction of Centrifugal Compressor
comparison, it can be obtained that the result of keeping the specific volume Based on Performance Test, Similarity Conversion andratio of inlet and outlet is more accurate than the result of maintaining Ma CFD Simulation
number. Then the test result is compared with the similarity result and thenumerical result when the working substance is air. It is obtained that thesimilarity result is more consistent with the test result better than the numericalresult and the trend of efficiency and pressure ratio change with the flow rateis consistent with the test result. In the process of similar conversion, theefficiency η is no useful for similitude design and it has less influence on theconversion result.
Abstract

Keywords

The present study is devoted to the influence of a superposed radial inflow ina rotor-stator cavity with a peripheral opening. The flow regime is turbulent,
the two boundary layers being separated by a core region. An original
theoretical solution is obtained for the core region, explaining the reason why
49-59

Influence of a weak superposed centripetal flow in a

Fadi Abdel Nour, Andrea Rinaldi, Roger Debuchy, Gérotor-stator system for several pre-swirl ratios

rard Boisa weak radial inflow has no major influence near the periphery of the cavity
rotor-stator cavity, turbulent flow, superposed radial
but strongly affects the flow behavior near the axis. The validity of the theory
inflow, analytical solution
is tested with the help of a new set of experimental data including the radial
and tangential mean velocity components, as well as three components of the
Reynolds stress tensor measured by hot-wire anemometry. The theoreticalresults are also in good agreement with numerical results obtained with the
Fluent code and experimental data from the literature.

60-64

Axial Wall Slits Effect on the Helical Flow in the Gap
between two Concentric Cylinders

Liu Dong, Yang Xiao-yong, Ding Jian, Kim HyoungBum

The helical flow regime was investigated by using DPIV when the rotating
Reynolds number is small. The wall slits were azimuthally located along theinner wall of outer cylinder and the slits number of each model was 9 and 18,
another plain wall model was also studied for comparison purpose. The helical
Helical flow regime, Slit wall, DPIV, Negative
vortex flow regime can be observed in all the three models. The negative
temperature gradient, Flow transition
temperature gradients determine the direction of the rotation and movementof the helical vortex. But the helical wavy vortex flow can only be found in theplane and 9-slit models. And the result showed that the existence of slit wall
accelerated the transition process.

Thomas Manoj Kumar Dundi, Nekkanti Sitaram,
Munivenkatareddy Suresh

The objective of the present investigation is to explore the possibility of
improving the performance of a centrifugal fan at low Reynolds numbers
using a simple passive means, namely Gurney flap (GF). GFs of 1/8th inch
brass angle (3.175 mm) corresponding to 15.9% of blade exit height or 5.1%of blade spacing at the impeller tip are attached to the impeller blade tip on
the pressure surface. Performance tests are carried out on the centrifugal fan
with vaneless diffuser at five Reynolds numbers (viz., 0.30, 0.41, 0.55, 0.69,
0.82x105, i.e., at five speeds respectively at 1,100, 1,500, 2,000, 2,500 and 3,000rpm) without and with GF. Static pressures on the vaneless diffuser hub and Centrifugal fan, Gurney flap, Experimental
shroud are also measured for each speed at four flow coefficients [φ=0.23 investigation, Performance, Static pressure(below design flow coefficient), φ=0.34 (design flow coefficient), φ=0.45(above design flow coefficient) and φ=0.60 (above design flow coefficient)]
with and without GF. From the performance curves it is found that theperformance of the fan improves considerably with GFs at lower Reynolds
numbers and improves marginally at higher Reynolds number. Similar
improvements are observed for the static pressures on the diffuser hub andshroud. The effect of Reynolds number on the performance and staticpressures is considerable. However the effect is reduced with GFs.

Vol. 5, No.
2, AprilJune, 2012

65-71

72-90

91-99
Page

100-108

Application of Gurney Flaps on a Centrifugal Fan
Impeller

Computational Investigations of Impingement Heat
Transfer on an Effused Concave Surface

Effects of Misalignment of High Speed Flexible
Coupling on the Fighter Aircraft Transmission
Title

Improving Flow Distribution in a Suction Channel fora Highly Efficient Centrifugal Compressor

M. Ashok Kumar, Bhamidi V.S.S.S. Prasad

Nagesh Samikkanu, Abu Muhammed Junaid Basha
AuthorManabu Yagi, Takanori Shibata, Hiromi Kobayashi,
Masanori Tanaka, Hideo Nishida

A computational study is reported on flow and heat transfer characteristics
from five rows of circular air jets impinging on a concave surface with fourrows of effusion holes. The effects of exit configurations of spent air and theGas turbine blade cooling, Impingement cooling, Filmarrangement of jet orifices and effusion holes for a jet Reynolds number ofholes, CFD
7500 is investigated. In all, eight cases are studied and a good qualitative
correlation is found among their flow patterns, pressure variations and heattransfer distributions
The Fighter aircraft transmission system consists of a light weight, High Speed Flexible Couplings, Misalignment, rotor dynamics,
Flexible Coupling (HSFC) known as Power Take-Off shaft (PTO) for connecting system dynamics and simulation, Experimental
Abstract
Keywords
Design parameters for suction channels of process centrifugal compressors
were investigated, and an optimization method to enhance stage efficiency byusing the new design parameters was proposed. From results of computational
fluid dynamics, the passage sectional area ratios Ac/Ae, Ae/As and Ac/As were
found to be the dominant parameters for the pressure loss and circumferential
Design parameter, Suction channel, Compressor,
flow distortion, where Ac, Ae and As are passage sectional areas for the casing
Stage efficiency, Circumferential flow distortion
upstream side, casing entrance and impeller eye, respectively. The Base suction
channel was optimized using the new design parameters, and the Base andOptimized types were tested. Test results showed that the Optimized suction
channel achieved 3.8% higher stage efficiency than the Base suction channel
while maintaining the same operating range.

Water hammer pumps can effectively use the water hammer phenomenon forwater pumping. They are capable of providing an effective fluid transport
method in regions without a well-developed social infrastructure. The resultsof experiments examining the effect of the geometric form of water hammer
pumps by considering their major dimensions have been reported. However,these conventional studies have not fully evaluated pump performance interms of pump head and flow rate, common measures of pump performance.
The authors have focused on the effects on the pump performance of various
geometric form factors in water hammer pumps. The previous study examined
how the hydrodynamic characteristics was affected by the inner diameter ratioof the drive and lift pipes and the angle of the drive pipe, basic form factors
Effects of the Lift Valve Opening Area on Water
Water Hammer Pump, Fluid Transients, Pump
Sumio Saito, Keita Dejima, Masaaki Takahashi, Gaku of water hammer pumps. The previous papers also showed that the behavior
109-116 Hammer Pump Performance and Flow Behavior in the
Performance, Pressure Fluctuation, Lift Valve Opening
Hijikata, Takuya Iwamuraof water hammer pump operation could be divided into four characteristic
Valve ChamberArea
phases. The behavior of temporal changes in valve chamber and air chamberpressures according to the air volume in the air chamber located downstreamof the lift valve was also clarified in connection with changes in water hammer
pump performance. In addition, the effects on water hammer pump
performance of the length of the spring attached to the drain valve and thedrain pipe angle, form factors around the drain valve, were examined
experimentally. This study focuses on the form of the lift valve, a major
component of water hammer pumps, and examines the effects of the size ofthe lift valve opening area on water hammer pump performance. It also
clarifies the behavior of flow in the valve chamber during water hammer pump
operation.

Vol. 5, No.
3, JulySeptember, 2012
117-125

126-133

Aspect-Ratio Effects and Unsteady Pressure
Measurements inside a Cross-Flow Impeller

erical Evaluation of Dynamic Transfer Matrix and
Unsteady Cavitation Characteristics of an Inducer

In the present experimental study, the authors try to clarify the characteristicsof the flow around and inside a cross-flow impeller in a typical geometry, overa wide parameter range of an aspect ratio L/D2. In order to eliminate thecomplicated casing factors, the impeller rotates in open space without any
casings. As a result, by using hot wire anemometer measurements and by
Katsuya Hirata, Yusuke Onishi, Shigeya Nagasaka, Ryo conventional flow visualisations with a particle image velocimetry technique, Cross-Flow Fan, Blower, Fan, Aspect Ratio, Pressure
Matsumoto, Jiro Funaki
the authors show that both the outflow rate and the maximum vorticity attain Measurement
the maximum for L/D2 = 0.6. In order to investigate the aspect-ratio effect, we
further reveal minute fluctuating pressures on an impeller end wall for a
singular L/D2 = 0.6. Especially in these pressure measurements, the eccentricvortex is prevented to revolute by the insertion of a tongue, in order toconsider the spatial structure of flow more precisely.
The transfer matrix and unsteady cavitation characteristics, cavitation
compliance and mass flow gain factor, of cavitating inducer were evaluated by
CFD using commercial software. Quasi-steady values of cavitation compliance
Koichi Yonezawa, Jun Aono, Donghyuk Kang, Hironori
Inducer, dynamic transfer matrix, cavitationand mass flow gain factor were obtained first by using steady calculations at
Horiguchi, Yutaka Kawata, Yoshinobu Tsujimoto
compliance, mass flow gain factor, CFD
various flow rate and inlet cavitation number. Then unsteady calculations weremade to determine the transfer matrix and the cavitation characteristics. The
results are compared with experiments to show the validity of calculations.

The competition to deliver ultra-low emitting vehicles at a reasonable cost is
driving the automotive industry to invest significant manpower and test
laboratory resources in the design optimization of increasingly complex
exhaust after-treatment systems. Optimization can no longer be based on
traditional approaches, which are intensive in hardware use and laboratory
testing. The CFD is in high demand for the analysis and design in order toreduce developing cost and time consuming in experiments. This paper
describes the development of a comprehensive practical model based on
experiments for simulating the performance of automotive three-way catalytic
converters, which are employed to reduce engine exhaust emissions. An
Experimental and computational analysis of behavior
134-142 of three-way catalytic converter under axial and radialflow conditions

Arif Zakaria Taibani, Vilas Kalamkar

experiment is conducted to measure species concentrations before and after
catalytic converter for different loads on engine. The model simulates theCatalyst, CFD modeling, chemical reaction, conversion
emission system behavior by using an exhaust system heat conservation and efficiency, simulation
catalyst chemical kinetic sub-model. CFD simulation is used to study theperformance of automotive catalytic converter. The substrate is modeled as aporous media in FLUENT and the standard k-e model is used for turbulence.
The flow pattern is changed from axial to radial by changing the substratemodel inside the catalytic converter and the flow distribution and theconversion efficiency of CO, HC and NOx are achieved first, and thepredictions are in good agreement with the experimental measurements. It isfound that the conversion from axial to radial flow makes the catalytic
converter more efficient. These studies help to understand better the
performance of the catalytic converter in order to optimize the converter
design.

Page

143-151

Title

Machine Condition Prognostics Based on Grey Modeland Survival Probability

AuthorStenly Tangkuman, Bo-Suk Yang, Seon-Jin Kim

Abstract

Keywords

Predicting the future condition of machine and assessing the remaining usefullife are the center of prognostics. This paper contributes a new prognostic
method based on grey model and survival probability. The first step of themethod is building a normal condition model then determining the error
indicator. In the second step, the survival probability value is obtained based Prognostics, Grey model, Survival probability,
on the error indicator. Finally, grey model coupled with one-step-ahead
Condition monitoring, Maintenanceforecasting technique are employed in the last step. This work has developed
a modified grey model in order to improve the accuracy of prediction. For
evaluating the proposed method, real trending data of low methane
compressor acquired from condition monitoring routine were employed.

Model tests and CFD were carried out to find out the cause of cavitation surge
in hydraulic power plants. In experiments the cavitation surge was observed atflow rates higher and lower than the swirl free flow rate, both with andwithout a surge tank placed just upstream of the inlet volute. The surge
frequency at smaller flow rate was much smaller than the swirl mode
Koichi Yonezawa, Daisuke Konishi, Kazuyoshi
frequency caused by the whirl of vortex rope. An unsteady CFD was carried
Cavitation Surge in a Small Model Test Facility
152-160
Miyagawa, François Avellan, Peter Doerfler, Yoshinobu out with two boundary conditions: (1) the flow rate is fixed to be constant at Draft tube surge, cavitation, Hydro turbine
Simulating a Hydraulic Power Plant
Tsujimotothe volute inlet, (2) the total pressure is kept constant at the volute inlet,
corresponding to the experiments without/with the surge tank. The surge wasobserved with both boundary conditions at both higher and lower flow rates.
Discussions as to the cause of the surge are made based on additional tests
with an orifice at the diffuser exit, and with the diffuser replaced with astraight pipe.
Vol. 5, No.
Small-sized axial fans are used as air coolers for electric equipment. There is a4,strong demand for higher power of fans according to the increase of quantity
Octoberof heat from electric devices. Therefore, higher rotational speed design is
December,conducted, although, it causes the deterioration of the efficiency and the2012
increase of noise. Then, the adoption of contra-rotating rotors for small-sizedfans is proposed for the improvement of the performance. In the case of
Influence of Blade Row Distance on Performance andcontra-rotating rotors, blade row distance between the front and the rear
Small-sized axial fan, Contra-rotating rotors,
161-167 Flow Condition of Contra-Rotating Small-Sized Axial Toru Shigemitsu, Junichiro Fukutomi, Hiroki Shimizu
rotors influences on the performance and the noise. Therefore, it is important Performance, Internal flow, Blade row distanceFan
to clarify the optimum blade row distance between front and rear rotors. The
performance curves of the contra-rotating small-sized axial fan under thecondition of different blade row distances are shown and the blade row
interaction between the front and the rear rotors are discussed by thenumerical results. Furthermore, the optimum blade row distance of the contrarotating small-sized axial fan is considered.
Numerical Investigation on Aerodynamic Performance
Jin-Hyuk Kim, Kyung-Hun Cha, Kwang-Yong Kim,
This paper presents a numerical investigation on the aerodynamic performance Centrifugal fan, impeller, splitter, pressure, efficiency,
168-173of a Centrifugal Fan with Splitter Blades
Choon-Man Jang
according to the application of splitter blades in an impeller of a centrifugal Reynolds-averaged Navier-Stokes equations
A numerical study to investigate the effect of intake vortex occurrence on theperformance of an axial hydraulic turbine for generating tidal power energy in
Sihwa-lake tidal power plant, Korea, is performed. Numerical analysis of theflow through an axial hydraulic turbine is carried out by solving threedimensional Reynolds-averaged Navier-Stokes equations with the shear stress
Effect of Intake Vortex Occurrence on the
Jin-Hyuk Kim, Man-Woong Heo, Kyung-Hun Cha,transport turbulence model. In the real turbine operation, the vortex flows are Sihwa-lake tidal power plant, axial hydraulic turbine,
174-179 Performance of an Axial Hydraulic Turbine in Sihwa- Kwang-Yong Kim, Se-Wyan Tac, Yong Cho, Jae-Chunoccurred in both the side corners around the intake of an axial hydraulicvortex flow behavior, numerical analysis, ReynoldsLake Tidal Power Plant, Korea
Hwang, Maria Collins
turbine due to the interaction between the inflow angle of water and intake averaged Navier-Stokes equations
structure. To analyze these vortex phenomena and to evaluate their impacts
on the turbine performance, the internal flow fields of the axial hydraulicturbines with the different inflow angles are compared with theirperformances. As the results of numerical analysis, the vortex flows do notdirectly affect the turbine performance.
Page

1-10

11-17

Title

Flow Analyses Inside Jet Pumps Used for Oil Wells

Performance and Internal Flow Condition of Mini
Centrifugal Pump with Splitter Blades

AuthorAbdus Samad, Mohammad Nizamuddin

Toru Shigemitsu, Junichiro Fukutomi, Kensuke Kaji,Takashi Wada

Abstract

Mini centrifugal pumps having a diameter smaller than 100mm are employedin many fields. But the design method for the mini centrifugal pump is notestablished because the internal flow condition for these small-sized fluid
machines is not clarified and conventional theory is not suitable for small-sizedpumps. Therefore, mini centrifugal pumps with simple structure were
investigated by this research. Splitter blades were adopted in this research to
improve the performance and the internal flow condition of mini centrifugal
pump which had large blade outlet angle. The original impeller without the
splitter blades and the impeller with the splitter blades were prepared for an
Mini centrifugal pump, Performance, Internal flow,
experiment. The performance tests are conducted with these rotors in order to
Splitter blade
investigate the effect of the splitter blades on performance and internal flow
condition of mini centrifugal pump. On the other hand, a three dimensional
steady numerical flow analysis is conducted with the commercial code
(ANSYS-CFX) to investigate the internal flow condition in detail. It is clarified
from experimental results that the performance of the mini centrifugal pump is
improved by the effect of the splitter blades. Blade-to-blade low velocity
regions are suppressed in the case with the splitter blades and total pressure
loss regions are decreased. The effects of the splitter blades on theperformance and the internal flow condition are discussed in this paper.

Vol. 6, No.
1,
JanuaryMarch,
2013

Keywords

Jet pump is one type of artificial lifts and is used when depth and deviation of
producing wells increases and pressure depletion occurs. In the present study,
numerical analysis has been carried out to analyze the flow behavior and findthe performance of the jet pump. Reynolds-averaged Navier Stokes equations
were solved and k-ε turbulence model was used for simulations. Water andlight oil as primary fluids were used to pump water, light oil and heavy oil. The
Artificial lift, well pumping, jet pump, hydraulic lift,
ratios of area and length to diameter of the mixing tube were considered as
primary fluid, secondary fluid
design parameters. The pump efficiency was considered to maximize for the
downhole conditions. It was found that the increase in viscosity and density ofthe secondary fluid reduced efficiency of the system. Water as primary fluid
produced better efficiency than the light oil. It was also found that the longer
throat length increased efficiency upto 40% if light oil was used as primary
fluid and secondary fluid viscosity was 350 cSt.

Vol. 6, No.
1,
JanuaryMarch,
2013

18-24

Design and Experimental Studies of Radial-Outflow
Type Diagonal Flow Fan

Yoichi Kinoue, Norimasa Shiomi, Toshiaki Setoguchi

In order to apply the design method of diagonal flow fan based on axial flow
design to the design of radial-outflow type diagonal flow fan which has lower
specific speed of 600-700 [min-1, m3/min, m], radial-outflow type diagonal
flow fan which specific speed was 670 [min-1, m3/min, m] was designed by aquasi three-dimensional design method. Experimental investigations were
Diagonal flow fan, Radial outflow, Five-hole probe,
conducted by fan characteristics test, flow surveys by a five-hole probe and a
Hot wire probe
hot wire probe. Fan characteristics test agreed well with the design values. In
the flow survey at rotor outlet, the characteristic region was observed. Twoflow phenomena are considered as the cause of the characteristic region, one
is tip leakage vortex near rotor tip and another is pressure surface separationon the rotor blade.
Data centers have been built with spread of cloud computing. Further, electric
power consumption of it is growing rapidly. High power cooling small-sized
fans; high pressure and large flow rate small-sized fan, are used for servers in
the data centers and there is a strong demand to increase power of it because

25-32Internal Flow Condition of High Power ContraRotating Small-Sized Axial Fan

Toru Shigemitsu, Junichiro Fukutomi, Takuya Agawa

33-48

An Outlook on the Draft-Tube-Surge Study

Michihiro Nishi, Shuhong Liu

Page

Title

Author

49-55

56-74

Water Lubricated Guide Bearing with Self-aligning
Segments

Analytical Study on Stall Stagnation Boundaries in
Axial-Flow Compressor and Duct Systems

75-86

Effects of Acoustic Resonance and Volute Geometryon Phase Resonance in a Centrifugal Fan

87-93

Fluid-Structure Interaction Study on Diffuser Pump
With a Two-Way Coupling MethodVol. 6, No.
2, AprilJune, 201394-104

Design and Prediction of Three Dimensional Flows ina Low Speed Highly Loaded Axial Flow Fan

Tadashi OGUMA, Naritoshi NAKAGAWA, Makoto
MIKAMI, Long THANTRONG, Yasumi KIZAKI, Fumio
TAKIMOTO

Nobuyuki Yamaguchi

of increase of quantity of heat from the servers. Contra-rotating rotors havebeen adopted for some of high power cooling fans to meet the demand forhigh power. There is a limitation of space for servers and geometricalrestriction for cooling fans because spokes to support fan motors, electrical
power cables and so on should be installed in the cooling fans. It is important Axial flow fan, Cooling fan, Performance, Internal flow
to clarify complicated internal flow condition and influence of a geometricshape of the cooling fans on performance to achieve high performance of thecooling fans. In the present paper, the performance and the flow condition of
the high power contra-rotating small-sized axial fan with a 40mm squarecasing are shown by experimental and numerical results. Furthermore,
influence of the geometrical shape of the small-sized cooling fan on theinternal flow condition is clarified and design guideline to improve theperformance is discussed.
If large pressure fluctuation is observed in the draft tube of a Francis turbine
at part-load operation, we have generally called it draft-tube-surge. As
occurrence of this phenomenon seriously affects the limit of turbine operating
range, extensive studies on the surge have been made since proposal ofsurge-frequency criterion given by Rheingans. According to the literature
survey of related topics in recent IAHR symposiums on hydraulic machineryand systems, in which state-of-the-art contributions were mainly presented, a draft tube, pressure surge, swirl flow, vortex rope,certain review of them may be desirable for an outlook on the future studies cavitation, review paperin this research field. Thus, in this review paper, the authors' previous attempts
for the last three decades to challenge the following topics: a rational method
for component test of a draft tube, nature of spiral vortex rope and its
behavior in a draft tube and cavitation characteristics of pressure fluctuations,
are introduced together with other related contributions, expecting that more
useful and significant studies will be accomplished in the future.
Abstract

Keywords

Water lubricated guide bearing was newly released and has been applied toactual hydro turbines with vertical shaft. As a result, they can have not only
high bearing performance but environmental advantages in meeting thedemand for reducing river pollution by oil leakage from oil lubricated guidebearing. The PTFE composite guide bearing was tested by experimental
Water lubricated guide bearing, PTFE, Tilting segment,
equipment operated under conditions similar to those of actual hydroVertical shaft hydro turbine, Hydrodynamic lubrication
turbines. Circumferential and axial tilting bearing segments help to improvethe bearing performance and efficiency due to low friction loss in the bearing
system. Furthermore, bearing cooling systems could be eliminated andmaintenance periods could be extended, thus the initial investment andoperating costs of the hydroelectric power plant are reduced.
Stall stagnations in the system of axial-flow compressors and ducts occur intransition from deep surge conditions to decayed or converged stallconditions. The present study is concerned with the boundaries between the
deep surges and the stagnation stalls on the basis of analytical results by acode on surge transients analysis and simulation. The fundamental acousticalgeometrical stagnation boundaries were made clear from examinations of theresults on a variety of duct configurations coupled with a nine-stagecompressor and a single stage fan. The boundary was found to be formed bythree parts, i.e., B- and A-boundaries, and an intermediate zone. The Bboundary occurs for the suction-duct having a length of about a quarter of Compressor, surge, stall, stall stagnation, unsteadythe wave-length of the first resonance in the case of very short and fat
flow, flow oscillation
plenum-type delivery duct. On the other hand, the A-boundary occurs for thelong and narrow duct- type delivery flow-path having a length about a fifth of
the wavelength and relatively small sectional area in the case of short andnarrow suction ducts. In addition to this, the reduced surge-cycle frequencies
with respect to the duct lengths are observed to have respective limiting
values at the stagnation boundaries. The reduced frequency for the Bboundary is related with a limiting value of the Greitzer's B parameter. The
tendency and the characteristic features of the related flow behaviors in theneighborhood of the boundaries were also made clearer.

The effects of acoustic resonance and volute geometry on phase resonanceare studied theoretically and experimentally using a centrifugal fan. One
dimensional theoretical model is developed taking account of the reflection
from the discharge pipe end. It was found that the phase resonance occurs,even with the effects of acoustic resonance, when the rotational speed ofrotor-stator interaction pattern agrees with the sound velocity. This was
confirmed by experiments with and without a silencer at the discharge pipe
exit. The pressure wave measurements showed that there are certain effects of
Yoshinobu Tsujimoto, Hiroshi Tanaka, Peter Doerfler,
the cross-sectional area change of the volute which is neglected in the one Phase resonance, acoustic resonance, rotor-stator
Koichi Yonezawa, Takayuki Suzuki, Keisuke Makikawa
dimensional model. To clarify the effects of area change, experiments were interaction, centrifugal fan
carried out by using a ring volute with a constant area. It was demonstrated
that the phase resonance occurs for both interaction modes travelling
towards/away from the volute. The amplitude of travelling wave grows
towards the volute exit for the modes rotating towards the volute exit, in thesame direction as the impeller. However, a standing wave is developed in thevolute for the modes rotating away from the volute exit in the opposite
direction as the impeller, as a result of the interaction of a growing wave while
travelling towards the tongue and a reflected wave away from the tongue.
Xu Huan, Liu Houlin, Tan Minggao, Cui Jianbao

In order to study the effect of the fluid-structure interaction (FSI) on the
Fluid-Structure Interaction, Diffuser Pump, Two-Way
simulation results, the external characteristics and internal flow features of a Coupling Method, head prediction

Xuejiao Liu, Liu Chen, Ren Dai, Ailing Yang

This paper describes the design to increase the blade loading factor of a low
speed axial flow fan from normal 0.42 to highly loaded 0.55. A threedimensional viscous solver is used to model the flows in the highly-loaded andnormal loaded stages over its operation range. At the design point operation
the static pressure rise can be increased by 20 percent with a deficit ofefficiency by 0.3 percent. In the highly loaded fan stage, the rotor hub flow
highly-loaded fan, numerical simulation, stage loadingstalls, and separation vortex extends over the rotor hub region. The backflow,
factorwhich occurs along the stator hub-suction surface, changes the exit flow fromthe prescribed axial direction. Results in this paper confirm that the limitationof the two dimensional diffusion does not affect primarily on the fan's
performance. Highly loaded fan may have actually better performance than its
two dimensional design. Three dimensional designing approaches may lead tobetter highly loaded fan with controlled rotor hub stall.

The application of contra-rotating rotors for higher specific speed pump has
been proposed in our studies, which is in principle effective for reducing therotational speed and/or the pump size under the same specification of
conventional axial flow pump. In the previous experiments of our prototype,105-112Low Speed Design of Rear Rotor in Contra-Rotating

Linlin Cao, Satoshi Watanabe, Simpei Momosaki,

Axial Flow Pump

Toshiki Imanishi, Akinori Furukawa

the cavitation inception at the tip region of the rear rotor rather than that of
the front rotor and the strong potential interaction from the suction surface ofthe rear rotor blade to the pressure surface of the front one were observed,
indicating the possibility to further improve the pump performance by
optimizing rotational speed combination between the two rotors. The present
research aims at the design of rear rotor with lower rotational speed.
Considering the fact that the incoming flow velocity defects at the tip regionof the rear rotor, an integrated inflow model of 'forced vortex' and 'freevortex' is employed. The variation of maximum camber location from hub to
tip as well as other related considerations are also taken into account for
further performance improvement. The ideas cited above are separately or

contra-rotating rotors, blade design, cavitation, CFD

comprehensively applied in the design of three types of rear rotor, which aresubsequently simulated in ANSYS CFX to evaluate the related pump
performance and therefore the whole low speed design idea. Finally, theexperimental validation is carried out on one type to offer further proofs forthe availability of the whole design method.
Page

113-120121-136

Title

Effect of Inlet Clearance Gap on the Performance ofan Industrial Centrifugal Blower with Parallel Wall
VoluteHexagonal reciprocating pump: advantages andweaknesses

137-143

Application of Constant Rate of Velocity or Pressure
Change Method to Improve Annular Jet Pump
Performance

144-151

Influence of Blade Number on the Flow
Characteristics in the Vertical Axis Propeller Hydro
Turbine152-159

A Study on Darrieus-type Hydroturbine toward
Utilization of Extra-Low Head Natural Flow Streams

Vol. 6, No.
3, JulySeptember, 2013

AuthorChinnasamy Hariharan, Mukka Govardhan

Milan Stanko, Michael Golan

This paper reports the 1-D fluid transient simulation results of the discharge
flow conditions in a 6-cylinder reciprocating slurry pump. Two discharge
manifold configurations are studied comparatively; a case with a hexagon
shaped discharge manifold where each cylinder discharges at a single vertex,
and a case where all the cylinders discharges are lumped together into a tank Hexagonal piston pump, pressure pulsation,
shaped manifold. In addition, the study examines the effect of two pulsation reciprocating piston pump
mitigation measures in the case of hexagonal manifold; a single inline orifice in
one of the hexagon sides and a volumetric dampener at the manifold outlet.
The study establishes the pressure and flow fluctuation characteristics of eachconfiguration and decouples the pulsation characteristics of the pump and thedischarge manifold.

problems such as flow rate change and flowing wastes to be solved for its
low head hydropower, Darrieus turbine, bypass flow,
Kei Tanaka, Kotaro Hirowatari, Kai Shimokawa, Satoshi practical use in natural flow streams. In the present study, at first, a design
waste screening system
Watanabe, Daisuke Matsushita, Akinori Furukawa
guideline in the case of overflow or bypass flow is shown by using simple flow
model. Next, in order to avoid the unexpected obstacles flowing into thehydroturbine, an installation of waste screening system is examined. It is
confirmed that the screen is effective with some amount of bypass flow rate,
however the output power is remarkably deteriorated.

Study of Mechanism of Counter-rotating Turbine
Increasing Two-Stage Turbine System Efficiency

Yanbin Liu, Weilin Zhuge, Xinqian Zheng, Yangjun
Zhang, Shuyong Zhang, Junyue Zhang

Page

Title

AuthorEffect of Axial Spacing between the Components on
the Performance of a Counter Rotating Turbine

Keywords

To improve annular jet pump (AJP) performance, new ways named constantrate of velocity/pressure change method (CRVC/CRPC) were adopted to design
its diffuser. The design formulas were derived according to the assumption of
linear velocity/pressure variation in the diffuser. Based on the two-dimensional
numerical simulations, the effect of the diffuser profile and the included angle
on the pump performance and the internal flow details has been analyzed.
Jet pump, turbulence model, annular jet pump,
Xuelong Yang, Xinping Long, Yong Kang, Longzhou
The predicted results of the RNG k-epsilon turbulence model show a better
diffuser, numerical simulation, structure optimization
Xiao
agreement with the experiment data than that of the standard and therealizable k-epsilon turbulence models. The AJP with the CRPC diffuser
produces a linear pressure increase in the CRPC diffuser as expected. The AJP
with CRPC/CRVC diffuser has better performance when the diffuser included
angle is greater or the diffuser length is shorter. Therefore, the AJP with
CRPC/CRVC diffuser is suitable for applications requiring space limitation andweight restriction.
In this paper, the design method of a low-head propeller-type hydro turbine isstudied for various numbers of blades on an axial propeller. We also
investigate the relationship between geometrical parameters and internal
performance parameters, such as angular velocities (100, 200, 300, 400 rpm)
and 2.5~4m low heads through a three-dimensional numerical method with
Propeller hydro turbine, Free vortex theory, Shaft
the SST turbulent model. The numerical results showed that the blade number
Sun-Seok Byeon, Youn-Jea Kim
power, Head, Blade number
had a more dominant influence than the change in heads and rotational
speed on the flow characteristics of the turbine. The distributions of pressureand velocity in the streamwise direction of the propeller turbine weregraphically depicted. Especially, the relationship among dimensionlessparameters like specific speed (Ns), flow coefficient (φ) and power coefficientwere investigated.
A two-dimensional Darrieus-type hydroturbine system, installed with a wear
for flow streams such as small rivers and waterways, has been developed forhydropower utilization of extra-low head less than 2m. There are several

160-169

170-176

Abstract

While performing numerical simulations, it is general industrial practice toneglect the clearance gap between the impeller and the inlet duct. In thepresent work, the effect of clearance gap on the performance of an industrial
sized centrifugal blower is simulated for two volutes of width ratios andvarious flow coefficients. The results show that the clearance has a positive Parallel wall volute, clearance gap, centrifugal blower
effect at low mass flow rates. This is observed in the pressure rise (1.3%) as
well as in efficiency (0.7%). At higher mass flow rates, it has a negative effectwith a drop in efficiency of 1% and pressure drop of about 1.4%. The effect ofclearance gap on volute with higher width ratio is smaller when comparedwith the volute with smaller width ratio.

Rayapati Subbarao, Mukka Govardhan

Two-stage turbocharging is an important way to raise engine power density,
to realize energy saving and emission reducing. At present, turbine matchingof two- stage turbocharger is based on MAP of turbine. The matching method
does not take the effect of turbines' interaction into consideration, assumingthat flow at high pressure turbine outlet and low pressure turbine inlet isuniform. Actually, there is swirl flow at outlet of high pressure turbine, and theswirl flow will influence performance of low pressure turbine which influencing
performance of engine further. Three-dimension models of turbines with twostage turbocharger were built in this paper. Based on the turbine models, Two-stage turbocharger, Swirl flow, Interaction, Radialmechanism of swirl flow at high pressure turbine outlet influencing low
counter-rotation turbine, Turbine efficiency, Threepressure turbine performance was studied and a two-stage radial counter- dimension simulation
rotation turbine system was raised. Mechanisms of the influence of counterrotation turbine system acting on low-pressure turbine were studied using
simulation method. The research result proved that in condition of small
turbine flow rate corresponding to engine low-speed working condition,
counter-rotation turbine system can effectively decrease the influence of swirl
flow at high pressure turbine outlet imposing on low pressure turbine andincreases efficiency of the low-pressure turbine, furthermore increases the lowspeed performance of the engine.
Abstract

Keywords

Counter Rotating Turbine (CRT) is an axial turbine with a nozzle followed by arotor and another rotor that rotates in the opposite direction of the first one.
Axial spacing between blade rows plays major role in its performance. Present
work involves computationally studying the performance and flow field of CRT
Counter Rotating Turbine, Axial Spacing, Turbinewith axial spacing of 10, 30 and 70% for different mass flow rates. The turbine
Performance, Pressure Coefficientcomponents are modeled for all the three spacing. Velocity, pressure, entropy
and Mach number distributions across turbine stage are analyzed. Effect of
spacing on losses and performance in case of stage, Rotor1 and Rotor2 areelaborated. Results confirm that an optimum axial spacing between turbine
components can be obtained for the improved performance of CRT.

177-187

189-199

A Second Order Exact Scaling Method for
Turbomachinery Performance PredictionPeter Franz Pelz, Stefan Sebastian Stonjek

Development of a Simulation Method of Surge
Transient Flow Phenomena in a Multistage Axial Flow

Nobuyuki Yamaguchi

A scaling method valid for most turbomachines based on first principles isderived. It accounts for axial and centri-fugal turbomachines with respect torelative gap width / tip clearance, relative roughness, Reynolds number and/or Scaling, Efficiency, Axial, Centrifugal, Turbine,
Mach number for design and off-design operation as well. The scaling method Compressor, Fan, Reynolds number, Mach number,has been successfully validated by a va-riety of experimental data obtained at Size, Tip Clearance, Gap, Roughness
TU Darmstadt. The physically based, hence reliable and universal method iscompared with previous, empirical scaling methods.
A practical method of surge simulation in a system of a high-pressure-ratio
multistage axial flow compressor and ducts, named SRGTRAN, is described

Fluid Machine, Axial Flow Compressor, Surge, Fluid
Dynamics, Analytical Simulation, Transient Flow

In order to investigate the characteristics of unsteady flow in a mixed flow
pump guide vane under the small flow conditions, several indicator points in amixed flow pump guide vane was set, the three-dimensional unsteadyturbulence numerical value of the mixed flow pump which is in the whole flow
field will be calculated by means of the large eddy simulation (LES), sub-grid200-205

The Numerical Simulation of Unsteady Flow in a
Mixed flow Pump Guide Vane

Li Yi-bin, Li Ren-nian, Wang Xiu-yongVol. 6, No.
4,
OctoberDecember,2013

206-212Wang Jian, Li Jiangyun, Guan Kai, Ma Tianyou

213-221

Experimental Study on Performance of a Propulsive
Nozzle with a Blower Piping System

Masahiko Sakamoto

Page

Title

Author

1-6

7-15

Vol. 7, No.
1,
JanuaryMarch,
2014

Study on the frequency of self-excited pulse jet

16-27

28-33

Experiment Investigation on Fluid Transportation
Performance of Propellant Acquisition Vanes in
Microgravity Environment

Baotang Zhuang, Yong Li, Xianwu Luo, Halin Pan,
Jingjing Ji

scale model and sliding mesh technology. The experimental results suggestthat the large eddy simulation can estimate the positive slope characteristic ofhead & capacity curve. And the calculation results show that the pressure
fluctuation coefficients of the middle section in guide vane inlet will decrease
firstly and then increase. In guide vane outlet, the pressure fluctuation
Mixed-flow Pump, Guide Vane, Pressure fluctuation,coefficients of section will be approximately axially symmetrical distribution. Vortex, LES, CFD
The pressure fluctuation minimum of section in guide vane inlet is above themiddle location of the guide vane suction surface, and the pressure fluctuation
minimum of section in which located the middle and outlet of guide vane.
When it is under the small flow operating condition, the eddy scale of guidevane is larger, and the pressure fluctuation of the channel in guide vane being
cyclical fluctuations obviously which leads to the area of eddy expanding to
the whole channel from the suction side. The middle of the guide vane suction
surface of the minimum amplitude pressure fluctuation to which the vortex
core of eddy scale whose direction of fluid's rotation is the same to impeller inthe guide vane adhere.
Self-excited pulse jet is a specific nozzle with a closed chamber which canchange a continuous jet into a pulse one. Energy of the pulse jet can be
output not only unevenly but also with multifrequency. With the peak pressureof pulse jet, the hitting power would be 2~2.5 times higher than that ofcontinuous jet. In order to reveal the correlation between the self-excited pulse
frequency and nozzle diameter ratio, nozzle spacing and operating pressure,the model of 3D unsteady cavitation model has been used. We found that Self-excited, Pulse Jet, Frequency, Numericalwith the same nozzle structure parameters and the different operating
Simulationpressure, the self-excited frequency and the width of peak crest are different,
but the wave profiles are similar. With FFT, we also found that the lessbandwidth of amplitude in low frequency range will lead to the wider wave
crest of outlet velocity in its time domain, and the larger force of the strike will
be gained. By studying the St of self-excite nozzle, not only the frequency of acertain nozzle can be predicted, but also a nozzle structure with a certain
frequency can be designed.
The characteristics of the thrust for ship propulsion equipment directly driven
by air compressed by pressure fluctuation in a blower piping system areinvestigated. The exhaust valve is positioned upon the air ejection hole in the
discharge pipe in order to induce the large-scale pressure fluctuation, and theeffects of the valve on the pressure in the pipes and the thrust for the
propulsive nozzle are examined. The pressure in the pipes decreases
Ship propulsion, water jet, pressure fluctuation,
immediately after the valve is opened, and it increases just before the valve isblower, pipe line, fluid machinery
closed. The thrust for the propulsive nozzle monotonically increases withincreasing number of revolutions and depth. The interfacial wave in the nozzle
appears in the frequency of approximately 4Hz, and it is important for theincrease of the thrust to synchronize the opening-closing cycle for the exhaust
valve with the generation frequency of the interfacial wave. The finite
difference lattice Boltzmann method is helpful to investigate the characteristicsof the flow in the nozzle.
Abstract

Keywords

The propellant acquisition vane (PAV) is a key part of a vane type surface
tension propellant management device (PMD), which can manage thepropellant effectively. In the present paper, the fluid transportation behaviors
for five PAVs with different sections were investigated by using microgravity
drop tower test. Further, numerical simulation for the propellant flow in a PMD
under microgravity condition was also carried out based on VOF model, andshowed the similar flow pattern for PAVs to the experiment. It is noted thatthe section geometry of PAVs is one of the main factors affecting the fluid Microgravity, Propellant Acquisition Vanes, Fluid
transportation behavior of PMD. PAVs with bottom length ratio of 5/6 and 1/2 transportation, Experiment
have larger propellant transportation velocity. Based on the experiments, there
were two stages during the process of propellant transportation under
microgravity environment: liquid relocation and steady transportation stage. It
is also recognized that there is a linear correlation between liquidtransportation velocity and relative time's square root. Those results can not
only provide a guideline for optimization of new vane type PMDs, but also arehelpful for fluid control applications in space environment.

In the present study, a computational analysis of the flow in a centrifugal
blower is carried out to predict a performance and to explain noisecharacteristics of the blower. Unsteady, 3D Navier-Stokes equations weresolved with k-ε turbulence model using CFX software. CFD results werecompared with the experimental data that is acquired from an experiment
Numerical Investigation on the Characteristics ofconducted with the same blower. The pressure fluctuation in the blower was centrifugal blower, wall pressure fluctuation, flowChanyoung Lee, Taebin Jeong, Kyoung-Ku Ha, ShinFlow-Induced Noise in a Centrifugal Blower
transformed into the frequency domain by Fourier decomposition to find the induced noise
Hyoung Kang
relationship between flow behaviors and noise characteristics. Sound pressurelevel (SPL) which is obtained from wall pressure fluctuation at impeller outlet
represents relative overall sound level of the blower well. Sound spectra showthat there are some specific peak frequencies at each mass flow rate and it
can be explained by flow pattern.
Double-blade vertical axis wind turbines (DB-VAWTs) can improve the selfstarting performance of lift-driven VAWTs. We here propose the quadruplemultiple streamtube model (QMS), based on the blade element momentum(BEM) theory, for simulating DB-VAWT performance. Model validity is
Predicting Double-Blade Vertical Axis Wind Turbine
investigated by comparison to computational fluid dynamics (CFD) prediction
Yutaka Hara, Takafumi Kawamura, Hiromichi Akimoto,
Wind turbine, Double-blade rotor, VAWT, BEM, CFD,
Performance by a Quadruple-Multiple Streamtube
for two kinds of two-dimensional DB-VAWT rotors for two rotor scales withKenji Tanaka, Takuju Nakamura, Kentaro Mizumukai
QMS
Model
three inner-outer radius ratios: 0.25, 0.5, and 0.75. The BEM-QMS model does
not consider the effects of an inner rotor on the flow speed in the upwind halfof the rotor, so we introduce a correction factor for this flow speed. The
maximum power coefficient predicted by the modified BEM-QMS model for a
DB-VAWT is thus closer to the CFD prediction.
In order to research the relationship between the tip clearance and leakage
flow of centrifugal compressor, a high speed centrifugal compressor wasinvestigated by using CFD. A numerical study on the effect of four different
rotor tip clearance sizes of centrifugal compressor, which were 0.5times, 1
times, 1.5times and 2.0times of the design tip clearance, was carried out.
Efficiency and pressure ratio curves were obtained under different mass flow.
Numerical simulation Analysis of Tip Clearance Flow
The reasons of the clearance vortex and the factors of vortex size were
Leakage flow, Tip clearance, Pressure ratio, Pressure
Shuiqing Zhou, Jun Wang, Chuanghua Wang, Ye Li
in a Centrifugal Compressor
analyzed. The result indicated that with the increase of tip clearance size, the difference
performance of the compressor changed obviously, the performanceparameters such as efficiency and pressure ratio tended to decrease obviously.
While, the leakage flow does not always lead to leak vortex. The strength ofthe vortex increased with the tip clearance. The size of leak vortex was affectedby the pressure difference between the suction side and the pressure side ofblade tip.

Computational fluid dynamics (CFD) and particle image velocimetry (PIV) arecommonly used techniques to evaluate the flow characteristics in thedevelopment stage of blood pumps. CFD technique allows rapid change topump parameters to optimize the pump performance without having to

34-41

Flow Evaluation and Hemolysis Analysis of BVAD
Centrifugal Blood Pump by Computational Fluids
Dynamics

construct a costly prototype model. These techniques are used in theconstruction of a bi-ventricular assist device (BVAD) which combines thefunctions of LVAD and RVAD in a compact unit. The BVAD construction
consists of two separate chambers with similar impellers, volutes, inlet andJeerasit Bumrungpetch, Andy Chit Tan, Shu-Hong Liu,
output sections. To achieve the required flow characteristics of an average flow Blood Pump, Ventricular Assist device, LVAD, BVAD,
Xian-Wu Luo, Qing-Yu Wu, Jian-Ping Yuan, Ming-Kui
rate of 5 l/min and different pressure heads (left – 100mmHg and right –Computational fluid dynamics, artificial heart
Zhang
20mmHg), the impellers were set at different rotating speeds. From the CFD
results, a six-blade impeller design was adopted for the development of the
BVAD. It was also observed that the fluid can flow smoothly through thepump with minimum shear stress and area of stagnation which are related tohaemolysis and thrombosis. Based on the compatible Reynolds number theflow through the model was calculated for the left and the right pumps. As it
was not possible to have both the left and right chambers in the experimental
model, the left and right pumps were tested separately.

Page
42-53

54-59

60-67

Vol. 7, No.
2, AprilJune, 2014

68-79

AuthorKoichi Yonezawa, Shingo Toyahara, Shingo Motoki,
Hiroshi Tanaka, Peter Doerfler, Yoshinobu Tsujimoto

Abstract
Keywords
Phase resonance in Francis type hydraulic turbine is studied. The phase
Phase resonance, rotor-stator interaction, centrifugal
resonance is a phenomenon that the pressure fluctuation in the penstock of fluid machinery, pump, turbine, flow rate fluctuation
Particle Image Velocimetry combined with developed image processing
method is adopted to study the liquid-solid two phase flow in the centrifugal
pump impeller with crystallization phenomenon. The tracer particle is used tofollow the liquid phase, which has the diameter between 8 to 12μm. The
crystal particle precipitates from the sodium sulfate solution does change thewavelength of the laser, and which has great laser scattering characteristics .
The diameter of the crystal particle is larger than 20μm. Through calculating
the diameter of the particles in the image, the tracer particle and the crystal
Research of liquid-solid two phase flow in centrifugal Liu Dong, Wang Ya-yun, Wang Ying-ze, Wang Chunparticle can be distinguished. By analyzing the experimental result, theCentrifugal pump, crystallization phenomenon, PIV,
pump with crystallization phenomenon
lin, Yang min-guanfollowing conclusion has been obtained. During the delay period, there is not image processing method
any crystal particle and the pump performance has not been changed. As the
crystallization process begins, the crystal nuclei appears from thesupersaturation solution and grows larger with temperature decreasing, which
has the tendency of moving towards the pressure side. The characteristics ofliquid-solid two phase flow with crystallization phenomenon in the pump are
obtained according to analysis of experimental results, and some guiding
advices are presented to mitigate the crystallization phenomenon in pump
impeller.
In order to clarify the effect of inlet bellmouth size of semi-opened type axial
fan on its performance and flow fields around rotor, fan test and flow fieldmeasurements using hotwire anemometer were carried out for 6 kinds ofbellmouth size. As results of fan test, the shaft power curve hardly changed,
even if the bellmouth size changed. On the other hand, the pressure-rise near
best efficiency point became small with the bellmouth size decreasing.
Effect of Inlet Geometry on Fan Performance andPin Liu, Norimasa Shiomi, Yoichi Kinoue, Toshiaki
Therefore, the value of maximum efficiency became small as the bellmouth Fan, semi-opened, inlet geometry, measurement
Inlet Flow Fields in a Semi-opened Axial Fan
Setoguchi, Ying-zi Jinsize decreased. As results of flow field measurements at fan inlet, the main
flow region with large meridional velocity existed near blade tip when thebellmouth size was large. As bellmouth size became smaller, the meridional
velocity at fan inlet became smaller and the one at outside of blade tip
became larger. As results of flow field measurements at fan outlet, the main
flow region existed near rotor hub side.
The type of turbine developed is based on the very low head of water
potential source for the electric power production. The area of research is
focused for the axial water turbine that can be applied at the simple site open
channel with has a very low cost and environmental impact compared to theconventional hydro installation. High efficiency of axial turbine which applied
to the very low potential head will made this type of turbine can be used at
Design and Simulation of Very Low Head Axial
wider potential site. Existing irrigation weir and river area will be the perfect
Axial turbine, very low head turbines, swirl velocity,
Hydraulic Turbine with Variation of Swirl Velocity
Abdul Muis, Priyono Sutikno
site for this turbine. This paper will compare the effects of the variation of swirl
vortex, ANSYS Fluent
Criterion
velocity criterion during the design of the blade of guide vane and rotor of
the turbine. Effects of the swirl velocity criterion is wider known as a vortex
conditions (free vortex, force vortex and swirl velocity constant), and the freevortex is the very popular condition that applied by most of turbine designer,
therefore will be interesting to do a comparison against other criterion. ANSYS
Fluent will be used for simulation and to determine the predictive performanceobtained by each of design criteria.
In this study, we visualized the internal flow of a regenerative turbomachinery
using the direct injection tracer method. For visualization, the working fluid
was water and the tracer was oil colors (marbling colors). Droplets were
injected at the inlet of the machinery and the streak were recorded using ahigh-speed camera with high-power light sources. While circulating inside thegroove, the droplets were translated by the rotational motion of the impeller. Regenerative Turbomachinery, Internal Circulation Flow,
Flow Visualization, Direct Injection Tracer Method
When the droplets flow out of the impeller groove, relative to the impeller,
they moved more slowly. And the droplets repeatedly reentered into thegroove and circulated again. Then the droplets either flowed to the outlet or
to the stripper. As a result, this experiment has confirmed the internal
circulating flow of a regenerative turbomachinery.

80-85

Visualization of Flow inside a Regenerative
Turbomachinery

Yang Hyeonmo, Lee Kyoung-yong, Choi Youngseok,Jeong Kyungseok

Page

Title

Author

Abstract

Choon-Man Jang, Hyun-Jun Jeon

This paper describes performance enhancement of a regenerative blower used
for a 20 kW fuel cell system. Two design variables, bending angle of an
impeller and blade thickness of an impeller tip, which are used to define an
impeller shape, are introduced to enhance the blower performance. Internal
flow of the regenerative blower has been analyzed with threedimensional
Navier-Stokes equations to obtain the blower performance. General analysis
code, CFX, is introduced in the present work. SST turbulence model is
employed to estimate the eddy viscosity. Throughout the numerical analysis, it
is found that the thickness of impeller tip is effective to increase the blower
efficiency in the present blower. Pressure is successfully increased up to 2.8%
compared to the reference blower at the design flow condition. And efficiency
is also enhanced up to 2.98 % compared to the reference one. It is noted thatlow velocity region disturbs to make strong recirculation flow inside the blade
passages, thus increases local pressure loss. Detailed flow field inside theregenerative blower is also analyzed and compared.

Shinya Hatano, Donghyuk Kang, Shusaku Kagawa,
Motohiko Nohmi, Kazuhiko Yokota

In double-suction centrifugal pumps, it was found that cavitation instabilities
occur with vibration and a perio dic chugging noise. The present study
attempts to identify cavitation instabilities in the double-suction centrifugal
pump by the experiment and Computational Fluid Dynamics (CFD). Cavitation
instabilities in the tested pump were classified into three types of instabilities.
The first one, in a range of cavitation number higher than breakdown
cavitation number, is cavitation surge with a violent pressure oscillation. The
second one, in a range of cavitation number higher than the cavitation
number of cavitation surge, is considered to be rotating cavitation and causes
the pressure oscillation due to the interaction of rotating cavitation with the
impeller. Last one, in a range of cavitation number higher than the cavitation
number of rotating cavitation, is considered to be a surge type instability.

86-93

94-100Vol. 7, No.
3, AprilJune, 2014

Title
Phase Resonance in Centrifugal Fluid Machinery-A Comparison between Pump Mode and Turbine

Performance Enhancement of 20kW Regenerative
Blower Using Design Parameters

Study of Cavitation Instabilities in Double- Suction
Centrifugal Pump

Keywords

Regenerative Blower, Design Parameter, Pressure,
Blower Efficiency, Numerical Simulation

Double-suction centrifugal pump, Cavitation
instability, Interaction of rotating cavitation with the
impeller

101-109

Fully coupled FSI analysis of Francis turbines exposed
Sailesh Chitrakar, Michel Cervantes, Biraj Singh Thapa
to sediment erosion

Vol. 7, No.
3, AprilJune, 2014

Sediment erosion is one of the key challenges in hydraulic turbines from adesign and maintenance perspective in Himalayas. The present study focuses
on choosing the best design in terms of blade angle distribution of a Francis
turbine runner which has least erosion effect without influencing the efficiency
and the structural integrity. A fully coupled Fluid-Structure-Interaction (FSI)
analysis was performed through a multi-field solver, which showed that the
maximum stress induced in the optimized design for better sediment handling,is less than that induced in the reference design. Some numerical validation
techniques have been shown for both CFD and FSI analysis.

CFD, FSI, Francis, Sediment, Erosion

Surge phenomena in the zone of reduced speeds in a system of a nine-stage
axial flow compressor coupled with ducts were studied analytically by use of asurge transient simulation code. Main results are as follows. (1) Expansion of
apparently stable, non-surge working area of the pressure vs. flow fieldbeyond the initial stage-stall line was predicted by the code in the lower

Surge Phenomena Analytically Predicted in a Multi110-124 stage Axial Flow Compressor System in the ReducedSpeed Zone

125-129

Paint Removal of Airplane & Water Jet Application

Page

Title

130141

Nobuyuki Yamaguchi

Author

Abstract

As a high specific speed pump, the contra-rotating axial flow pump with tworotors rotating reversely has been proved with higher hydraulic and cavitation
performance, while in our previous researches, the potential interaction
between two blade rows was distinctly observed for our prototype rotors
designed with equal rotational speed for both front and rear rotors. Based on
the theoretical and experimental evidences, a rotational speed optimization
methodology was proposed and applied in the design of a new combinationof contra-rotating rotors, primarily in expectation of the optimized blade
pressure distributions as well as pertinently improved hydraulic performances
including cavitation performance. In the present study, given one stationary
Experimental Investigation of Blade-To-Blade Pressure Linlin Cao, Satoshi Watanabe, Hironori Honda, Hiroaki
and two rotating frames in the contra-rotating rotors case, a pressure
Distribution in Contra-Rotating Axial Flow Pump
Yoshimura, Akinori Furukawa
measurement concept taking account of the revolutions of both front and rearrotors simultaneously was adopted. The casing wall pressure data sampled intime domain was successfully transferred into space domain, by which theensemble averaged blade-to-blade pressure distributions at the blade tip of
two contra-rotating rotors under different operation conditions were studied.
It could be seen that the rotor pair with the optimized rotational speed
combination as well as work division, shows more reasonable blade-to-blade
pressure distribution and well weakened potential interaction. Moreover,combining the loading curves estimated by the measured casing wall pressure,the cavitation performance of the rotor pairs with new rotational speed
combination were proved to be superior to those of the prototype pairs.

Study on the Development of Two-Stage Centrifugal
Blood Pump for Cardiopulmonary Support System

Hironori Horiguchi, Tomonori Tsukiya, Takeshi
Nomoto, Toratarou Takemika, Yoshinobu Tsujimoto

151159Experimental and Numerical Investigations on
Performances of Darriues-type Hydro Turbine with
Inlet Nozzle

Daisuke Matsushita, Kei Tanaka, Satoshi Watanabe,
Kusuo Okuma, Akinori Furukawa

160173

A Study on the Fundamental Surge Frequencies inMulti-Stage Axial Flow Compressor Systems

Fluid Machine, Compressor, Surge, Analytical
Simulation, Transient Flow, Fluid Dynamics

The paint removal and recoating are the very important process in airplane
maintenance. The traditional technology is to use the chemical way corroding
the paint with paint remover. For changing the defects, corrosion & pollution& manual working, of the traditional technology, the physical process whichremoves the paint of airplane with 250MPa/250kW ultra-high pressure rotarywater jetting though the surface cleaner installed on the six axes robot isstudied. The paint layer of airplane is very thin and close. The contradiction of Airplane surface, Paint removal, Ultra-high pressure,
Xue Sheng-xiong, Chen Zheng-wen, Ren Qi-le, Su Jiwater jetting paint removal is to remove the paint layer wholly and not
Water jetting technology, Six axes robot, Test
xin, Han Cai-hong, Pang lei
damage the surface of airplane. In order to solve the contradiction, the best
researchworking condition must be reached through tests. The paint removal efficiency
with ultra-high pressure and move speed of not damaged to the surface. The
move speed of this test is about 2m/min, and the paint removal efficiency isabout 30~40m2 /h, and the paint removal active area is 85-90%. No-repeat
and no-omit are the base requests of the robot program. The physical paintremoval tec hnology will be applied in airplane maintenance, and will face thesafety detection of application permission.

142150Vol. 7, No.
4,
OctoberDecember,
2014

speed region. The area proved analytically to be caused by significantly
mismatched stage- working conditions, particularly with the front stages deepin the rotating stall branch of the characteristics, as was already known in situ
and in steady-state calculations also. (2) Surge frequencies were found toincrease for decreasing compressor speeds as far as the particular compressor
system was concerned. (3) The tendency was found to be explained by a
newly introduced volumemodified reduced surge frequency. It suggests thatthe surge frequency is related intimately with the process of emptying andfilling of air into the delivery volume. (4) The upstream range of movement of
the fluid mass having once passed through the compressor in surge wasfound to reduce toward the lower speeds, which could have caused
additionally the increase in surge frequency. (5) The concept of the volumemodified reduced surge frequency was able to explain, though qualitatively atpresent, the behaviors of the area- pressure ratio parameter for the stall
stagnation boundary proposed earlier by the author.

Nobuyuki Yamaguchi

Keywords

Axial flow pump, contra-rotating rotors, blade rows
interaction, pressure measurement

In the cardiopulmonary support system with an ECMO (extracorporeal
membrane oxygenation), ahigher pump head is demanded for a blood pump.
In order to realize a blood pump with higher pump head, higher antihemolysis and thrombosis performances, astudy on the development of
unprecedented multistage blood pump was conducted. In consideration of the Centrifugal Pump, Artificial Heart, Blood, Hemolysis,
applicationof the blood pump for pediatric patients, a miniature two-stage
Thrombosis
centrifugal blood pump with the impeller’s diameter of40mm was designed
and the performance was examined in experiments and computations. Someuseful knowledge for a design of the blood pump with higher anti-hemolysis
and thrombosis performances was obtained.
Low head hydropower is one of realistic renewable energies. The Darrieus-typehydro turbine with an inlet nozzle is available for such low head conditions
because of its simple structure with easy maintenance. Experimental andnumerical studies are carried out in order to examine the effects of gap
low head hydropower, Darrieus turbine, inlet
distances between the runner pitch circle and two edges of inlet nozzle on
nozzleedge
turbine performances. By selecting narrower gaps of left and right edges, thegap, performance test
performance could be improved. From the results of two dimensional
numerical simulations, the relation between the performance and flow
behaviors around the Darrieus blade are discussed to obtain the guideline ofappropriate inlet nozzle design.
Surge phenomena in multi-stage axial flow compressors were studied withattention to the frequency behaviors. A new parameter “volume-modified
reduced surge frequency” was introduced, which took into consideration theessential surge process, i.e., emptying and filling of the working gas in thedelivery plenum. The behaviors of the relative surge frequencies at the stall
stagnation boundaries, compared with the corresponding duct resonancefrequencies, have demonstrated the existence of two types of surges; i.e., anear-resonant surge and a subharmonic surge. The former, which has
fundamentally a near-resonance frequency, occurs predominantly at the stall
stagnation boundary for the short-and-fat plenum delivery flow-path and thelong-and-narrow delivery duct flow-path, and possibly in the intermediate
conditions. The latter, which has a subharmonic frequency of the fundamental
near-resonant one and occurs mainly in the inter-mediate zone, is considered
to be caused by the reduced frequency restricted to a limited range. In
relation with those dimensionless frequencies at the stall stagnation boundary,
the surge frequency behaviors in more general situations away from theboundaries could be estimated, though very roughly.

Fluid Machine, Axial Flow Compressor, Surge,
Analytical Simulation, Frequency, Fluid Dynamics

The ultimate objective of this study is to develop a water turbine appropriate
for low-head open channels to effectively utilize the unused hydropower
energy of rivers and agricultural waterways. The application of a cross-flowrunner to open channels as an undershot water turbine has been considered
and, to this end, a significant simplification was attained by removing theturbine casing. However, the flow field of an undershot cross-flow water

174182The Flow Field of Undershot Cross-Flow Water
Turbines Based on PIV Measurements and Numerical
AnalysisYasuyuki Nishi, Terumi Inagaki, Yanrong Li, Ryota
Omiya, Kentaro Hatano

turbine possesses free surfaces, and, as a result, the water depth around therunner changes with variation in the rotational speed such that the flow field
itself is significantly altered. Thus, clear understanding of the flow fields
observed with free surfaces to improve the performance of this turbine is

Water Turbine, Cross-Flow Turbine, Open Channel,
Free Surface, Particle Image Velocimetry, Numerical
Analysis

necessary. In this study, the performance of this turbine and the flow field
were evaluated through experiments and numerical analysis. The particle
image velocimetry technique was used for flow measurements. The
experimental results reflecting the performance of this turbine and the flow
field were consistent with numerical analysis. In addition, the flow fields at the
inlet and outlet regions at the first and second stages of this water turbine
were clarified.

Page

112

Title

Improvement of Two-Stage Centrifugal Blood Pump
for Cardiopulmonary Support System and Evaluationof Anti-Hemolysis Performance

AuthorHironori Horiguchi, Tomonori Tsukiya, Toratarou
Takemika, Takeshi Nomoto, Yoshinobu Tsujimoto

Abstract

Keywords

In cardiopulmonary support systems with a membrane oxygenation such as apercutaneous cardiopulmonary support (PCPS) or an extracorporeal membrane
oxygenation (ECMO), blood pumps need to generate the pressure rise of
approximately 200mmHg or higher, due to the high hydraulic resistances ofthe membrane oxygenation and of the cannula tubing. In order to realize theblood pump with higher pressure rise, higher anti-hemolysis and thrombosis
Centrifugal Pump, Artificial Heart, Blood, Hemolysis,
performances, the development of novel centrifugal blood pump composed ofThrombosis
two-stage has been conducted by the authors. In the present paper, effective
attempts to decrease the wall shear stress and to suppress the stagnation are
introduced for the prevention of hemolysis and thrombosis in blood pumps.
The hemolysis test was also carried out and it was clarified that the decreaseof wall shear stress is effective as a guideline of design of blood pumps for
improving the anti-hemolysis performance.

1322

2335

Vol. 8, No.
1,
JanuaryMarch,2015

Performance Evaluation of a Variable Frequency Heat
Pump Air Conditioning System for Electric Bus

Rotordynamic Performance Measurements of An OilFree Turbocharger Supported on Gas Foil Bearings
and Their Comparisons to Floating Ring Bearings

Qinghong Peng, Qungui Du

Yong-Bok Lee, Dong-Jin Park, Kyuho Sim

36Numerical Analysis of Centrifugal Impeller for Different Viscous Liquids
Sayed Ahmed Imran Bellary, Abdus Samad
45

4654

Hydrodynamic Design of Thrust Ring Pump for Large
Hydro Turbine Generator Units

This study presents a simulation model of a heat pump air conditioning
system with a variable capacity compressor and variable speeds fans forelectric bus. An experimental sample has been developed in order to check
results from the model. Effects on system performance of such working
conditions as compressor speed, evaporator fans speeds and the condenser
fans speeds have been simulated by means of developed model. The results
show that the three speeds can be adjusted simultaneously according toactual working condition so that the AC system can operate under the
optimum state which the control objects want to achieve. It would be a goodand simple solution to extend the driving ranges of EVs because of thehighest efficiency and the lowest energy consumption of AC system

Air conditioning, Heat pump, Electric bus, EER,
Variable frequency

This paper presents the rotordynamic performance measurement of oil-freeturbocharger (TC) supported on gas foil bearings (GFBs) for 2 liter class diesel
vehicles and comparison to floating ring bearings (FRBs). Oil-free TC wasdesigned and developed via the rotordynamic analyses using dynamic force
coefficients from GFB analyses. The rotordynamics and performance of the oilfree TC was measured up to 85 krpm while being driven by a diesel vehicle
turbocharger, gas foil bearings, floating ring
engine, and compared to a commercial oil-lubricated TC supported on FRBs.
bearings, rotordynamic performance
The test results showed that the GFBs increased the rotor speed by ~ 20% atengine speeds of 1,500 rpm and 1,750 rpm, yielding the reduction of turbine
input energy by more than 400 W. Incidentally, an external shock test on theoil-free TC casing was conducted at the rotor speed of 60 krpm, and showed agood capability of vibration damping due to the well-known dry friction
mechanism of the GFBs.
Oil and gas industry pumps viscous fluids and investigation of flow physics isimportant to understand the machine behavior to deliver such fluids. 3D
numerical flow simulation and analysis for different viscous fluids at different
rotational speeds of a centrifugal impeller have been reported in this paper.
Reynolds-averaged Navier Stokes (RANS) equations were solved and theCentrifugal impeller, Off design condition, Rotational
performance analysis was made. Standard two equation k-ε model was used
speed, Viscosity, Inlet recirculation
for the turbulence closure of steady incompressible flow. An inlet recirculation
and reverse flow in impeller passage was observed at low impeller speeds. It
was also found that the higher viscosity fluids have higher recirculation whichhinders the impeller performance.

Xide Lai, Xiang Zhang, Xiaoming Chen, Shifu Yang

Thrust-ring-pump is a kind of extreme-low specific speed centrifugal pump with special
structure as numerous restrictions from thrust bearing and operation conditions ofhydro-generator units. Because the oil circulatory and cooling system with thrust-ringpump has a lot of advantages in maintenance and compactness in structure, it has
widely been used in large and medium-sized hydro-generator units. Since the diameterand the speed of the thrust ring is limited by the generator set, the matching
relationship between the flow passage inside the thrust ring (equivalent to impeller)
and oil bath (equivalent to volute) has great influence on hydrodynamic performanceof thrust-ring-pump. On another hand, the head and flow rate are varying with theoperation conditions of hydro-generator units and the oil circulatory and coolingsystem. As so far, the empirical calculation method is employed during the actual
engineering design, in order to guarantee the operating performance of the oil
circulatory and cooling system with thrust-ring-pump at different conditions, acollaborative hydrodynamic design and optimization is purposed in this paper. Firstly,
the head and flow rate at different conditions are decided by 1D flow numericalsimulation of the oil circulatory and cooling system. Secondly, the flow passages ofthrust-ring-pump are empirically designed under the restrictions of diameter and the
speed of the thrust ring according to the head and flow rate from the simulation.
Thirdly, the flow passage geometry matching optimization between thrust ring and oilbath is implemented by means of 3D flow simulation and performance prediction.
Then, the pumps and the oil circulatory and cooling system are collaborativehydrodynamic optimized with predicted head-flow rate curve and the efficiency-flowrate curve of thrust-ring-pump. The presented methodology has been adopted byThrust-ring-pump, Hydrodynamic design, Thrustbearing, Lubricating and cooling system, Hydro
turbine generator, Low specific speed centrifugal
pumpMethod of characteristics, Hydraulic transient,
Discharge propagation, Saint-Venant equations
Numerical Approach, Hydraulic Systems

Keywords

5562

Case studies for solving the Saint-Venant equations
using the method of characteristics: pipeline hydraulictransients and discharge propagation

Regina Mambeli Barros, Geraldo Lúcio Tiago Filho,
Ivan Felipe Silva dos Santos

This study aims to present a hydraulic transitory study as MOC applications forsolving the Saint-Venant equations in two case studies: 1) in a penstock of asmall hydropower system as a simple pipeline in the case of valve-closure in
the downstream boundary with a reservoir in the upstream boundary; and 2)
for discharge propagation into a channel by velocity and depth of the flow
channel along space evaluation. The proposed methodology by Chaudry [5]concerning the development of hydrodynamic models was used. The obtained
results for first and second case study has been confirmed that MOC
numerical approach is useful for several engineering purposes, including casesof hydraulic transients and discharge propagation in hydraulic systems.

Page

Title

Author

AbstractWater hammer phenomena are important issues for the design and theoperation of hydro power plants. Especially, if several reversible pump-turbines
are coupled hydraulically there may be strong unit interactions. The precise
prediction of all relevant transients is challenging. Regarding a recent pump-

36-72

Improved prediction of Pump Turbine Dynamic
Behavior using a Thoma number dependent Hill Chartand Site Measurements

Maximilian Manderla, Karl N. Kiniger, Jiri Koutnik

storage project, dynamic measurements motivate an improved turbine
modeling approach making use of a Thoma number dependency. The
pump turbine, hydraulic transients, turbine
proposed method is validated for several transient scenarios and turns out to modelling, draft tube pressure, Thoma number,
improve correlation between measurement and simulation results significantly. automated simulation
Starting from simple scenarios, this allows better prediction of more complex
transients. By applying a fully automated simulation procedure broad
operating ranges of the highly nonlinear system can be covered providing aconsistent insight into the plant dynamics. This finally allows the optimizationof the closing strategy and hence the overall power plant performance.
Aerating hydroturbines have recently been proposed as an effective way to

73-83

84-93

Vol. 8, No.
2, AprilJune, 2015

94-101

102-112

Bubble size characteristics in the wake of ventilatedhydrofoils with two aeration configurations

Accelerating CFD-DEM simulation of dilute pneumaticconveying with bends

Numerical studies on cavitation behavior in impellerof centrifugal pump with different blade profiles

Simulations of the Dynamic Load in a Francis Runnerbased on measurements of Grid Frequency Variations

mitigate the problem of low dissolved oxygen in the discharge of hydroelectric
power plants. The design of such a hydroturbine requires a precise
understanding of the dependence of the generated bubble size distribution
upon the operating conditions (viz. liquid velocity, air ventilation rate, hydrofoil
configuration, etc.) and the consequent rise in dissolved oxygen in thedownstream water. The purpose of the current research is to investigate theAshish Karn, Christopher R Ellis, Christopher Milliren, effect of location of air injection on the resulting bubble size distribution, thus Ventilated hydrofoil, Hydroturbine aeration, Shadow
Jiarong Hong, David Scott, Roger E A Arndt, John S leading to a quantitative analysis of aeration statistics and capabilities for two Image Velocimetry, Bubble size distribution, AutoGulliver
turbine blade hydrofoil designs. The two blade designs differed in their
venting turbines
location of air injection. Extensive sets of experiments were conducted byvarying the liquid velocity, aeration rate and the hydrofoil angle of attack, tocharacterize the resulting bubble size distribution. Using a shadow imaging
technique to capture the bubble images in the wake and an in-housedeveloped image analysis algorithm, it was found that the hydrofoil withleading edge ventilation produced smaller size bubbles as compared to thehydrofoil being ventilated at the trailing edge.

Jun Du, Guoming Hu, Ziqiang Fang, Wenjie Gui

Pengfei Song, Yongxue Zhang, Cong Xu, Xin Zhou,
Jinya Zhang

Rakel Ellingsen, Pål-Tore Storli

The computational cost is expensive for CFD-DEM simulation, a larger time
step and a simplified CFD-DEM model can be used to accelerate thesimulation. The relationship between stiffness and overlap in non-linear
Hertzian model is examined, and a reasonable time step is determined by a
new single particle test. The simplified model is used to simulate dilute
pneumatic conveying with different types of bends, and its applicability isverified by compared with the traditional model. They are good agreement inhorizontal-vertical case and vertical-horizontal case, and show a significant
differences in horizontal-horizontal case. But the key features of particle rope
formed in different types of bends can be obtained by both models.

CFD-DEM, dilute pneumatic conveying, time step

To investigate the influence of blade profiles on cavitation behavior in impellerof centrifugal pump, a centrifugal pump with five different blade profiles
impellers are studied numerically. The impellers with five different blade
profiles (single arc, double arcs, triple arcs, logarithmic spiral and linear variable angle spiral) were designed by the in-house hydraulic design codeusing geometric parameters of IS 150-125-125 centrifugal pump. The
experiments of the centrifugal pump have been conducted to verify numericalsimulation model. The numerical results show that the blade profile lines has aweak effect on cavitation inception near blade inlet edge position, however it Centrifugal pump, Blade profile, Cavitation behavior,
has the key effect on the development of sheet cavitation in impeller, and also Numerical simulationinfluences the distribution of sheet cavitation in impeller channels. A slightchanging of blade setting angle will induce significant difference of cavitationin impeller. The sharp changing of impeller blade setting angle causes obvious
cavitation region separation near the impeller inlet close to blade suction
surface and much more flow loss. The centrifugal pump with blade profile ofsetting angle gently changing (logarithmic spiral) has the super cavitation
performance, which means smaller critical cavitation number and lower vapor
cavity volume fraction at the same conditions.
In the Nordic grid, a trend observed the recent years is the increase in gridfrequency variations, which means the frequency is outside the normal range(49.9-50.1 Hz) more often. Variations in the grid frequency leads to changes inthe speed of rotation of all the turbines connected to the grid, since the speedof rotation is closely related to the grid frequency for synchronous generators.
When the speed of rotation changes, this implies that the net torque acting on
the rotating masses are changed, and the material of the turbine runners mustwithstand these changes in torque. Frequency variations thus leads to torqueoscillations in the turbine, which become dynamical loads that the runner must
be able to withstand. Several new Francis runners have recently experienced
cracks in the runner blades due to fatigue, obviously due to the runner design
not taking into account the actual loads on the runner. In this paper, theGrid Frequency Variations, Torque Oscillations, 1D
torque oscillations and dynamic loads due to the variations in grid frequency
Simulations, Francis turbine, Dynamic loading
are simulated in a 1D MATLAB program, and measured grid frequency is used
as input to the simulation program. The maximum increase and decrease in
the grid frequency over a 440 seconds interval have been investigated, in
addition to an extreme event where the frequency decreased far below thenormal range within a few seconds. The dynamic loading originating from gridfrequency variations is qualitatively found by a constructed variable Tstress,
and for the simulations presented here the variations in Tstress are found to
be around 3 % of the mean value, which is a relatively small dynamic load.
The important thing to remember is that these dynamic loads come inaddition to all other dynamic loads, like rotor-stator interaction and draft tube
surges, and should be included in the design process, if not found to be
negligible.

113-123

CFD-based Design and Analysis of the Ventilation of
an Electric Generator Model, Validated with
Experiments

Hamed Jamshidi, Håkan Nilsson, Valery Chernoray

Page

Title

Author

The efficiency of the ventilation system is a key point for durable and reliable
electric generators. The design of such system requires a detailed
understanding of the air flow in the generator. Computational fluid dynamics(CFD) has the potential to resolve the lack of information in this field. The
present work analyses the air flow inside a generator model. The model isdesigned using a CFD-based approach, and manufactured by taking into
consideration the experimental and numerical requirements and limitations.
The emphasis is on the possibility to accurately predict and experimentallymeasure the flow distribution inside the stator channels. A major part of thework is focused on the design of an intake and a fan that gives an evenly
Experiments, CFD, Electric Generator and Ventilation
distributed flow with a high flow rate. The intake also serves as an accurate
flowmeter. Experimental results are presented, of the total volume flow rate,
the total pressure and velocity distributions. Steady-state CFD simulations are
performed using the FOAM-extend CFD toolbox. The simulations are based on
the multiple rotating reference frames method. The results from the frozen
rotor and mixing plane rotor-stator coupling approaches are compared. It isshown that the fan design provides a sufficient flow rate for the statorchannels, which is not the case without the fan or with a previous fan design.
The detailed experimental and numerical results show an excellent agreement,
proving that the results reliable.
Abstract

Keywords

The good performance of a vortex shedder is defined by strong and stablevortex generated under the condition of most linearity in Strouhal number andlow power loss. In this paper, the flow past a bluff body of circular cylinder
with a slit normal to the flow has been analyzed focusing on drag coefficient,linearity of Strouhal number and flow resistance (K-factor). The ANSYS/FLUENT
package is used for flow simulation and the integration method of
124-131

Numerical Study of Important Factors for a Vortex
Shedder using Automated Design Cycle

Su Myat Nyein, He Xu

computational code to iSIGHT platform is employed for automated design
cycle. This study results the design with (0.20~0.267) blockage ratio and 0.10

drag coefficient, linearity of Strouhal number, Kfactor, integration of GAMBIT, FLUENT, iSIGHT

slit ratio as the best shedder for vortex flowmeter and this results are in wellagreement with the experiment. As the combination of GAMBIT, FLUENT, andiSIGHT substitutes the design parameters automatically according to the input
data, this method designs effectively the vortex shedder with less design cycle

132-141

CFD Analysis for Aligned and Misaligned Guide Vane
Torque Prediction and Validation with Experimental
Data

142-154

3D Casing-Distributor Analysis for Hydraulic Design
Application

155-168

Comparison of steady and unsteady simulation
methodologies for predicting no-load speed in

169-182

Simulation model for Francis and Reversible Pump
Turbines

Christophe Devals, Thi C. Vu, François Guibault

Nowadays, computational fluid dynamics is commonly used by design
engineers to evaluate and compare losses in hydraulic components as it is lessexpensive and less time consuming than model tests. For that purpose, anautomatic tool for casing and distributor analysis will be presented in thispaper. An in-house mesh generator and a Reynolds Averaged Navier-Stokes
equation solver using the standard k-ω shear stress transport (SST) turbulencemodel will be used to perform all computations. Two solvers based on theChristophe Devals, Ying Zhang, Julien Dompierre, Thi C++ OpenFOAM library will be used and compared to a commercial solver.
CFD, Casing-Distributor Analysis, OpenFOAM, Block
C. Vu, Luca Mangani, François Guibault
The performance of the new fully coupled block solver developed by the
Coupled Solver
University of Lucerne and Andritz will be compared to the standard 1.6ext
segregated simpleFoam solver and to a commercial solver. In this study,
relative comparisons of different geometries of casing and distributor will be
performed. The present study is thus aimed at validating the block solver andthe tool chain and providing design engineers with a faster and more reliable
analysis tool that can be integrated into their design process.

Hossein Hosseinimanesh, Christophe Devals, Bernd
Nennemann, François Guibault

Torbjørn K. Nielsen

Vol. 8, No.
3, JulySeptember, 2015183-192

193-201202-208

Comparative study of sediment erosion on alternative
designs of Francis runner blade

Leakage Flow Influence on SHF pump model
performances

Numerical Investigation of Pressure Fluctuation
Reducing in Draft Tube of Francis Turbines

time and low manufacturing cost eliminating the human intervention
bottleneck.
This paper presents a CFD-based methodology for the prediction of guidevane torque in hydraulic turbine distributor for aligned and misaligned
configurations. A misaligned or desynchronized configuration occurs when the
opening angle of one guide vane differs from the opening angle of all other
Torque, Guide Vane, CFD, Casing, Distributor
guide vanes, which may lead to a torque increase on neighbouring guidevanes. A fully automated numerical procedure is presented, that automates
computations for a complete range of operation of a 2D or 3D distributor.
Results are validated against laboratory measurements.

Bidhan Rajkarnikar, Dr. Hari P. Neopane, Biraj S.
Thapa

No-load speed is an important performance factor for the safe operation ofhydropower systems. In turbine design, the manufacturers must conduct

No-load speed, runaway speed, Francis turbine,
steady-state simulation, unsteady state simulation

When simulating the dynamic behaviour of a hydro power plant, it is essential
to have a good representation of the turbine behaviour. The pressuretransients in the system occurs because the flow changes, which the turbine
defines. The flow through the turbine is a function of the pressure, the speedof rotation and the wicket gate opening and is, most often described in a
performance diagram or Hill diagram. In the Hill diagram, the efficiency isdrawn like contour lines, hence the name. A turbines Hill diagram is obtainedby performance tests on scaled model in a laboratory. However, system
dynamic simulations have to be performed in the early stage of a project,
before the turbine manufacturer has been chosen and the Hill diagram is
known. Therefore one have to rely on diagrams for a turbine with similar
Hydropower, Turbines, Characteristics, Simulation
speed number. The Hill diagram is drawn through measured points, so forusing the diagram in a simulation program, one have to iterate in the diagram
based on curve fitting of the measured points. This paper describes analternative method. By means of the Euler turbine equation, it is possible toset up two differential equations which represents the turbine performancewith good enough accuracy for the dynamic simulations. The only input is theturbine’s main geometry, the runner blade in- and outlet angle and the guidevane angle at best efficiency point of operation (BEP). In the paper, simulated
turbine characteristics for a high head Francis turbine, and for a reversible
pump turbine are compared with laboratory measured characteristics.

The aim of this study was comparative analysis of sediment-induced erosion
on optimized design and traditional design of Francis runner blade. The
analysis was conducted through laboratory experiments in a test rig called
Rotating Disc Apparatus. The results showed that the extent of erosion was
significantly less in the optimized design when compared based on thematerial loss. It was observed that the optimized design could reduce
sediment erosion by about 14.4% if it was used in place of the reference
design for entire duration of the experiment. Based on the observations andresults obtained, it has been concluded that the optimization of hydraulicdesign of blade profile of Francis runner can significantly reduce the effect of
sediment-induced erosion.

Francis turbine, optimized design, rotating discapparatus, runner blade, sediment erosion, wear
patternThis paper deals with the influence of leakage flow existing in SHF pumpmodel on the analysis of internal flow behaviour inside the vane diffuser of thepump model performance using both experiments and calculations. PIV
measurements have been performed at different hub to shroud planes inside
one diffuser channel passage for a given speed of rotation and various flow
rates. For each operating condition, the PIV measurements have been triggedwith different angular impeller positions. The performances and the staticpressure rise of the diffuser were also measured using a three-hole probe. The
numerical simulations were carried out with Star CCM+ 9.06 code (RANS
frozen and unsteady calculations). Some results were already presented at the
Patrick Dupont, Annie-Claude Bayeul-Lainé, Antoine
pump, numerical calculations, performances,
XXth IAHR Symposium for three flowrates for RANS frozen and URANS
Dazin, Gérard Bois, Olivier Roussette, Qiaorui Si
unsteady flow, vaned diffuser, radial flow pumpcalculations. In the present paper, comparisons between URANS calculations
with and without leakages and experimental results are presented anddiscussed for these flow rates. The performances of the diffuser obtained bynumerical calculations are compared to those obtained by the three-holesprobe measurements. The comparisons show the influence of fluid leakages on
global performances and a real improvement concerning the efficiency of the
diffuser, the pump and the velocity distributions. These results show thatleakage is an important parameter that has to be taken into account in orderto make improved comparisons between numerical approaches andexperiments in such a specific model set up.

W F Li, J J Feng, H Wu, J L Lu, W L Liao, X Q Luo

For a prototype turbine operating under part load conditions, the turbine
output is fluctuating strongly, leading to the power station incapable ofconnecting to the grid. The field test of the prototype turbine shows that themain reason is the resonance between the draft tube vortex frequency and thegenerator natural vibration frequency. In order to reduce the fluctuation of
power output, different measures including the air admission, water admission
and adding flow deflectors in the draft tube are put forward. CFD method is
Francis turbine, draft tube vortex, air supply, water
adopted to simulate the three-dimensional unsteady flow in the Francis
supply, flow deflector
turbine, to calculate pressure fluctuations in draft tube under three schemes
and to compare with the field test result of the prototype turbine. Calculation
results show that all the three measures can reduce the pressure pulsation
amplitude in the draft tube. The method of water supply and adding flow
deflector both can effectively change the frequency and avoid resonance, thus
solving the output fluctuation problem. However, the method of air admission
could not change the pressure fluctuation frequency.

209-219

Physics-based Surrogate Optimization of Francis
Turbine Runner Blades, Using Mesh Adaptive Direct
Search and Evolutionary Algorithms

Salman Bahrami, Christophe Tribes, Sven vonFellenberg, Thi C. Vu, François Guibault

A robust multi-fidelity optimization methodology has been developed,
focusing on efficiently handling industrial runner design of hydraulic Francis
turbines. The computational task is split between low- and high-fidelity phases
in order to properly balance the CFD cost and required accuracy in different
design stages. In the low-fidelity phase, a physics-based surrogate
optimization loop manages a large number of iterative optimization
evaluations. Two derivative-free optimization methods use an inviscid flow
solver as a physics-based surrogate to obtain the main characteristics of a

Physics-based surrogate optimization, Francis turbine
runner blade, multi-fidelity algorithm

good design in a relatively fast iterative process. The case study of a runnerdesign for a low-head Francis turbine indicates advantages of integrating two
derivative-free optimization algorithms with different local- and global searchcapabilities.

220

Erratum to: Numerical Investigation of Pressure
Fluctuation Reducing in Draft Tube of Francis

W F Li, J J Feng, H Wu, J L Lu, W L Liao, X Q Luo

An error has been found in the footnote in page 202.

TurbinesPage

221-229230-239240-253

254-263264-273

Vol. 8, No.
4,
OctoberDecember,
2015

Title

The Performance Analysis Method with New Pressure
Loss and Leakage Flow Models of Regenerative
BlowerStudy on Flow Instability and Countermeasure in a
Draft tube with Swirling flow

Investigation of Cavitation Models for Steady and
Unsteady Cavitating Flow Simulation

The effect of materials properties on the reliability of
hydraulic turbine runners

AuthorChan Lee, Hyun Gwon Kil, Kwang Yeong Kim

Takahiro Nakashima, Ryo Matsuzaka, Kazuyoshi
Miyagawa, Koichi Yonezawa, Yoshinobu Tsujimoto

Abstract

Keywords

F﻿or efficient design process of regenerative blower, the present study provides
new generalized pressure and leakage flow loss models, which can be used in
the performance analysis method of regenerative blower. The present
performance analysis on designed blower is made by incorporating
momentum exchange theory between impellers and side channel with meanline analysis method, and its pressure loss and leakage flow models are
generalized from the related fluid mechanics correlations which can be
expressed in terms of blower design variables. The present performance
Regenerative Blower, Performance Analysis, Pressure
analysis method is applied to four existing models for verifying its prediction
Loss, Leakage Flow, CFD
accuracy, and the prediction and the test results agreed well within a few
percentage of relative error. Furthermore, the present performance analysis
method is also applied in developing a new blower used for fuel cellapplication, and the newly designed blower is manufactured and tested
through chamber-type test facility. The performance prediction by the present
method agreed well with the test result and also with the CFD simulation
results. From the comparison results, the present performance analysis method
is shown to be suitable for the actual design practice of regenerative blower.
The swirling flow in the draft tube of a Francis turbine can cause the flow
instability and the cavitation surge and has a larger influence on hydraulicpower operating system. In this paper, the cavitating flow with swirling flow inthe diffuser was studied by the draft tube component experiment, the modelFrancis turbine experiment and the numerical simulation. In the component
experiment, several types of fluctuations were observed, including thecavitation surge and the vortex rope behaviour by the swirling flow. While thecavitation surge and the vortex rope behaviour were suppressed by theaeration into the diffuser, the loss coefficient in the diffuser increased by theaeration. In the model turbine test the aeration decreased the efficiency of themodel turbine by several percent. In the numerical simulation, the cavitating
Draft tube, Cavitation, Hydro turbine, Vortrex rope,
flow was studied using Scale-Adaptive Simulation (SAS) with particular
Aerationemphasis on understanding the unsteady characteristics of the vortex rope
structure. The generation and evolution of the vortex rope structures havebeen investigated throughout the diffuser using the iso-surface of vapor
volume fraction. The pressure fluctuation in the diffuser by numericalsimulation confirmed the cavitation surge observed in the experiment. Finally,
this pressure fluctuation of the cavitation surge was examined and interpretedby CFD.

﻿he objective of this paper is to evaluate the applicability of mass transfer
Tcavitation models and determine appropriate numerical parameters forcavitating flow simulations. CFD simulations were performed for a NACA66
hydrofoil at cavitation numbers of 1.49 and 1.00, corresponding to steadysheet and unsteady sheet/cloud cavitating regimes using the Kubota and
Merkle cavitation models. The Merkle model was implemented into CFX byUser Fortran code. The Merkle cavitation model is found to give some
improvements for cavitating flow simulation results for these cases. Turbulence
Tan Dung Tran, Bernd Nennemann, Thi Cong Vu, Fran
Cavitation, CFD, steady, unsteady flow simulation,modeling is also found to have an important contribution to the predictionçois Guibault
turbulence, cavitation local compressibility
quality of the simulations. The relationship between the turbulence viscosity
modification, in order to take into account the local compressibility at thevapor/liquid interfaces, and the predicted numerical results is clarified. The
limitations of current cavitating flow simulation techniques are discussed
throughout the paper.

Denis Thibault, Martin Gagnon, Stéphane Godin﻿he failure of hydraulic turbine runners is a rare event. So in order to assessT
the reliability of these components one cannot rely solely on the number ofobserved failures in a given population. However, as there is a limited numberof degradation mechanisms involved, it is possible to use physically-based
reliability models. Such models are often more complicated but are able toaccount for physical parameters in the degradation process. They cantherefore help provide solutions to improve reliability. With such models, theeffect of materials properties on runner reliability can be highlighted. This
paper presents a brief review of the Kitagawa-Takahashi diagram which links
fatigue, reliability, stainless steel, hydraulic turbine,
the damage tolerance approach, based on fracture mechanics, to the stress or turbine runner, microstructurestrain-life approaches. Using simplified response spectra based on runnerstress measurements, we will show how fatigue reliability is sensitive tomaterials fatigue properties, namely fatigue crack propagation behaviour andfatigue limit obtained on S-N curves. Furthermore, we will review the influenceof the main microstructural features observed in 13%Cr-4%Ni stainless steels
commonly used for runner manufacturing. The goal is ultimately to identify
the most influential microstructural features and to quantify their effect on
fatigue reliability of runners.

This presentation describes an experimental approach for the detection ofcavitation in hydraulic machines by use of ultrasonic signal analysis. Instead ofusing the high frequency pulses (typically 1MHz) only for transit timemeasurement different other signal characteristics are extracted from theindividual signals and its correlation function with reference signals in order togain knowledge of the water conditions. As the pulse repetition rate is high(typically 100Hz), statistical parameters can be extracted of the signals. The
idea is to find patterns in the parameters by a classifier that can distinguishbetween the different water states. This classification scheme has been applied
to different cavitation sections: a sphere in a water flow in circular tube at the
HSLU in Lucerne, a NACA profile in a cavitation tunnel and two Francis model
test turbines all at LMH in Lausanne. From the signal raw data several
The detection of cavitation in hydraulic machines by P. Gruber, M. Farhat, P. Odermatt, M. Etterlin, T. Lerch,ultrasonic signals, cavitation, turbine, neural network,
statistical parameters in the time and frequency domain as well as from theuse of ultrasonic signal analysis
M. Freidecision treecorrelation function with reference signals have been determined. As classifiers
two methods were used: neural feed forward networks and decision trees. For
both classification methods realizations with lowest complexity as possible areof special interest. It is shown that two to three signal characteristics, two fromthe signal itself and one from the correlation function are in many cases
sufficient for the detection capability. The final goal is to combine these resultswith operating point, vibration, acoustic emission and dynamic pressure
information such that a distinction between dangerous and not dangerous
cavitation is possible.

Vol. 8, No.
4,
OctoberDecember,
2015

﻿his paper deals with the influence of leakage flow existing in SHF pumpTmodel on the analysis of internal flow behaviour inside the vane diffuser of thepump model performance using both experiments and calculations. PIV
measurements have been performed at different hub to shroud planes inside
one diffuser channel passage for a given speed of rotation and various flow
rates. For each operating condition, the PIV measurements have been trigged

274-282

Leakage Flow Influence on SHF pump model
performanceswith different angular impeller positions. The performances and the staticpressure rise of the diffuser were also measured using a three-hole probe. The
numerical simulations were carried out with Star CCM+ 9.06 code (RANS
frozen and unsteady calculations). Some results were already presented at theXXth IAHR Symposium for three flowrates for RANS frozen and URANS
Patrick Dupont, Annie-Claude Bayeul-Lainé, Antoine calculations. In the present paper, comparisons between URANS calculations
pump, numerical calculations, performances,
Dazin, Gérard Bois, Olivier Roussette, Qiaorui Si
unsteady flow, vaned diffuser, radial flow pumpwith and without leakages and experimental results are presented anddiscussed for these flow rates. The performances of the diffuser obtained bynumerical calculations are compared to those obtained by the three-holesprobe measurements. The comparisons show the influence of fluid leakages on
global performances and a real improvement concerning the efficiency of the
diffuser, the pump and the velocity distributions. These results show thatleakage is an important parameter that has to be taken into account in orderto make improved comparisons between numerical approaches andexperiments in such a specific model set up.

283-293

Quantitative and qualitative analysis of the flow fielddevelopment through T99 draft tube caused by
optimized inlet velocity profiles.

Selection of Optimal Number of Francis Runner
294-303 Blades for a Sediment Laden Micro Hydropower Plant
in Nepal

304-310311-317

Numerical simulation of slit wall effect on the Taylor
vortex flow with radial temperature gradientCorrection and Experimental Verification of Velocity
Circulation in a Double-blade Pump Impeller Outlet

Sergio Galván, Marcelo Reggio, François Guibault,
Gildardo Solorio

Binaya Baidar, Sailesh Chitrakar, Ravi Koirala, Hari
Prasad Neopane

The effect of the inlet swirling flow in a hydraulic turbine draft tube is a very
complex phenomenon, which has been extensively investigated boththeoretically and experimentally. In fact, the finding of the optimal flow
distribution at the draft tube inlet in order to get the best performance hasremained a challenge. Thus, attempting to answer this question, it was
assumed that through an automatic optimization process a Genetic Algorithm
would be able to manage a parameterized inlet velocity profile in order toachieve the best flow field for a particular draft tube. As a result of the
optimization process, it was possible to obtain different draft-tube flow
structures generated by the automatic manipulation of parameterized inlet
velocity profiles. Thus, this work develops a qualitative and quantitative
analysis of these new draft tube flow field structures provoked by the
Numerical optimization, Draft Tubes, Hydraulicredesigned inlet velocity profiles. The comparisons among the different flow
Turbines, Genetic Algorithm
fields obtained clearly illustrate the importance of the flow uniformity at theend of the conduit. Another important aspect has been the elimination of the
re-circulating flow area which used to promote an adverse pressure gradient in
the cone, deteriorating the pressure recovery effect. Thanks to the evolutionary
optimization strategy, it has been possible to demonstrate that the optimized
inlet velocity profile can suppress or mitigate, at least numerically, theundesirable draft tube flow characteristics. Finally, since there is only a single
swirl number for which the objective function has been minimized, the energy
loss factor might be slightly affected by the flow rate if the same relation of
the axial-tangential velocity components is maintained, which makes it
possible to scale the inlet velocity field to different operating points.
The present study is conducted to identify a better design and optimal
number of Francis runner blades for sediment laden high head microhydropower site, Tara Khola in the Baglung district of Nepal. The runner isdesigned with in-house code and Computational Fluid Dynamics (CFD)
analysis is performed to evaluate the performance with three configurations;11, 13 and 17 numbers of runner blades. The three sets of runners were also
investigated for the sediment erosion tendency. The runner with 13 blades
shows better performance at design as well as in variable discharge conditions.
CFD, Francis turbine, Sediment erosion, Efficiency,
96.2% efficiency is obtained from the runner with 13 blades at the design
Performance, Optimum number of blades
point, and the runners with 17 and 11 blades have 88.25% and 76.63%
efficiencies respectively. Further, the runner with 13 blades has better
manufacturability than the runner with 17 blades as it has long and highly
curved blade with small gaps between the blades, but it comes with 65% more
erosion tendency than in the runner with 17 blades.

Dong Liu, Chang-qing Chao, Fang-neng Zhu, Xiqiang Han, Cheng Tang

Numerical simulation was applied to investigate the Taylor vortex flow inside
the concentric cylinders with a constant radial temperature gradient. The
reliability of numerical simulation method was verified by the experimental
results of PIV. The radial velocity and temperature distribution in plain and 12slit model at different axial locations were compared, and the heat flux
Taylor vortex flow, Slit wall, temperature gradient,distributions along the inner cylinder wall at different work conditions wereheat transfer, numerical simulation
obtained. In the plain model, the average surface heat flux of inner cylinder
increased with the inner cylinder rotation speed. In slit model, the slit wall
significantly changed the distribution of flow field and temperature in theannulus gap, and the radial flow was strengthen obviously , which promoted
the heat transfer process at the same working condition.

Wang Kai, Liu Qiong

It is difficulty to calculate velocity circulation in centrifugal pump impeller
outlet accurately. Velocity circulations of a double-blade pump impeller outlet
were calculated with Stodola formula, Weisner formula and Stechkin formula.
Simultaneously, the internal flow of impeller for the double-blade pump were
measured with PIV technology and average velocity circulations at the 0.8, 1.0
and 1.2 times of design flow were obtained. All the experimental values werecompared with the above calculation values at the three conditions. The
Double-blade pump, Impeller, Velocity circulation,
results show that calculation values of velocity circulations with Weisner
PIV, Correction
formula is close to the experimental values. On the basis of the above, velocity
circulations of impeller outlet were corrected. The results of experimental
verification show that the corrected calculation errors, whose maximum error is
3.65%, are greatly reduced than the uncorrected calculation errors. The
research results could provide good references for establishment of theoreticalhead and multi-condition hydraulic optimization of double-blade pumps.

318-326

Modeling and testing for hydraulic shock regarding avalve-less electro-hydraulic servo steering device forships

Liao Jian, He Lin, Xu Rongwu

Page

Title

Author

A valve-less electro-hydraulic servo steering device (short: VSSD) for ships waschosen as a study object, and its mathematic model of hydraulic shock was
established on the basis of flow properties and force balance of eachcomponent. The influence of system structure parameters, changing rate of
motor speed and external load on hydraulic shock strength was simulated by valve-less, steering device, hydraulic shock, changing
the method of numerical simulation. Experiment was designed to test therate, accumulator, external load
hydraulic shock mathematic model of VSSD. Experiment results verified thecorrectness of the model, and the model provided a correct theoreticalmethod for the calculation and control of hydraulic shock of valve-lesselectro-hydraulic servo steering device.
Abstract

Keywords

Behaviors of surges appearing near the stall stagnation boundaries in various
fashions in systems of a single-stage compressor and flow-path systems werestudied analytically and were tried to put to order. Deep surges, which enclose
the stall point in the pressure-mass flow plane, tend to have either nearresonant surge frequencies or subharmonic ones. The subharmonic surge is amultiple-loop one containing, for example, in a (1/2) subharmonic one, a deep
surge loop and a mild surge loop, the latter of which does not enclose thestall point, staying only within the stalled zone. Both loops have nearly equal
time periods, respectively, resulting in a (1/2) subharmonic surge frequency as
a whole. The subharmonic surges are found to appear in a narrow zone
1-16

Analytical Surge Behaviors in Systems of a Singlestage Axial Flow Compressor and Flow-paths

Nobuyuki Yamaguchineighboring the stall stagnation boundary. In other words, they tend to
appear in the final stage of the stall stagnation process.It should beemphasized further that the stall stagnation initiates fundamentally at thesituation where a volume-modified reduced resonant-surge frequency
becomes coincident with that for the stagnation boundary conditions, where

Fluid Machine, Axial Flow Compressor, Surge,
Analytical Simulation, Frequency, Fluid Dynamics

the reduced frequency is defined by the acoustical resonance frequency in theflow-path system, the delivery flow-path length and the compressor tip speed,
modified by the sectional area ratio and the effect of the stalling pressure
ratio. The real surge frequency turns from the resonant frequency to either
near-resonant one or subharmonic one, and finally to stagnation condition, forthe large-amplitude conditions, caused by the non-linear self-excitation
mechanism of the surge.

17-27

Vol. 9, No.
1,
JanuaryMarch,
2016

Genesis of Researches on Surges in Pumping Systems
in JapanNobuyuki Yamaguchi, Yoshinobu Tsujimoto

28-38

Robust Design of Main Control Valve for HydraulicPile Hammer Flexible Control System

Guo Yong, Hu Jun Ping, Zhang Long Yan

39-46

Impact performance for high frequency hydraulic rock
drill drifter with sleeve valve

Guo Yong, Yang Shu Yi, Liu De Shun, Zhang Long
Yan, Chen Jian Wen

47-55

Study on Performance Improvement of an Axial Flow
Hydraulic Turbine with a Collection Device

Yasuyuki Nishi, Terumi Inagaki, Yanrong Li, Sou
Hirama, Norio Kikuchi

56

Erratum: The Flow Field of Undershot Cross-Flow
Water Turbines Based on PIV Measurements andNumerical Analysis

Yasuyuki Nishi, Terumi Inagaki, Yanrong Li, Ryota
Omiya, Kentaro Hatano

57-65

Numerical Analysis of Damping Effect of Liquid Filmon Material in High Speed Liquid Droplet
Impingement

Hirotoshi Sasaki, Naoya Ochiai, Yuka Iga

Researches on the mechanism of surging and the surge behaviors in thesystems of pumps, or fans or compressors, and the effects of flow-paths had
been initiated and had made a great progress in Japan in the decades fromthe nineteen-forties to the nineteen-sixties. In 1947, the essential cause of thesurges, i.e., self-excited oscillation nature of the flow-system, was discovered
analytically by Professor Sumiji Fujii of Tokyo University, and most of thecharacteristic behaviors of the phenomena had been explained clearly.
Successive studies by many other Japanese researchers continued to prove
Surge, pumps, compressors and fans, self-excited
experimentally the mechanism, to extend the analytical studies, and to attempt
oscillation, pressure-flow characteristics
preventing surge occurrence, etc. in the following two decades.
The historical information on the early surge studies could be helpful to someconcerned people. At the same time, the basic and plain ways of discussions
and reasoning about the phenomena in the pioneering researches could give
us much to be learned even in the present time of high-power computing
systems. Regrettably, many of the original research works have been publishedonly in Japanese. The present review introduces very briefly the situations inmemories of the pioneering researchers and engineers.
The flexible control system for hydraulic pile hammer using main control valve
is present to the requirement of rapidly reversing with high frequency. To
ensure the working reliability of hydraulic pile hammer, the reversing
performance of the main control valve should commutate robustness tovarious interfere factors. Through simulation model built in Simulink/Stateflow
and experiment, the effects of relative parameters to reverse performance ofmain control are analyzed and the main interfere factors for reversing
hydraulic pile hammer, main control valve, reversing
performance are acquired. Treating reverse required time as design objects,
performance, pile driving, Stateflow, robust design
some structure parameters as control factors, control pressure, input flow andgaps between spool and valve body as interfere factors, the robust design ofthe main control valve is done. The combination of factors with the strongest
anti-jamming capability is acquired which ensured the reliability and antijamming capability of the main control valve. It also provides guidance on
design and application of the main control valve used in large flow control
with interferes.
A high frequency hydraulic rock drill drifter with sleeve valve is developed touse on arm of excavator. In order to ensure optimal working parameters of
impact system for the new hydraulic rock drill drifter controlled by sleeve
valve, the performance test system is built using the arm and the hydraulicsource of excavator. The evaluation indexes are gained through measurementrock drill drift, sleeve valve, energy efficiency, impact
of working pressure, supply oil flow and stress wave. The relations of working
energy, feature moment of energy distribution
parameters to impact system performance are analyzed. The result
demonstrates that the maximum impact energy of the drill drifter is 98.34J
with impact frequency of 71HZ. Optimal pressure of YZ45 rock drill is 12.8
MPa-13.6MPa, in which the energy efficiency reaches above 58.6%, andfeature moment of energy distribution is more than 0.650.
The portable hydraulic turbine we previously developed for open channels
comprises an axial flow runner with an appended collection device and adiffuser section. The output power of this hydraulic turbine was improved bycatching and accelerating an open-channel water flow using the kinetic energyof the water. This study aimed to further improve the performance of thehydraulic turbine. Using numerical analysis, we examined the performancesand flow fields of a single runner and a composite body consisting of therunner and collection device by varying the airfoil and number of blades.
Hydraulic Turbine, Runner, Collection Device, Airfoil,
Consequently, the maximum values of input power coefficient of the Runner D Performance, Flow Field
composite body with two blades (which adopts the MEL031 airfoil and alters
the blade angle) are equivalent to those of the composite body with two
blades (MEL021 airfoil). We found that the Runner D composite body has thehighest turbine efficiency and thus the largest power coefficient. Furthermore,
the performance of the Runner D composite body calculated from thenumerical analysis was verified experimentally in an open-channel water flow
test.
Errors have been found in Vol. 7 (2014) No. 4 (October-December) pp. 174182.

By high speed Liquid Droplet Impingement (LDI) on material, fluid systems areseriously damaged, therefore, it is important for the solution of the erosion
problem of fluid systems to consider the effect of material in LDI. In this study,
by using an in-house fluid/material two-way coupled method which considers
Liquid droplet, Liquid film, Fluid/material coupledreflection and transmission of pressure, stress and velocity on the
numerical method, Homogeneous model, Elastic body
fluid/material interface, high-speed LDI on wet/dry material surface ismaterial
simulated. As a result, in the case of LDI on wet surface, maximum equivalentstress are less than those of dry surface due to damping effect of liquid film.
Empirical formula of the damping effect function is formulated with the fluid
factors of LDI, which are impingement velocity, droplet diameter and thicknessof liquid film on material surface.

Concerning the numerical simulation of high-speed water jet with intensive
cavitation this paper presents a practical compressible mixture flow method bycoupling a simplified estimation of bubble cavitation and a compressible
mixture flow computation. The mean flow of two-phase mixture is calculatedby URANS for compressible fluid. The intensity of cavitation in a local field isevaluated by the volume fraction of gas phase varying with the mean flow,
and the effect of cavitation on the flow turbulence is considered by applying adensity correction to the evaluation of eddy viscosity. High-speed submerged

66-74

Numerical Simulation of Unsteady Cavitation in a
High-speed Water Jet

water jets issuing from a sheathed sharp-edge orifice nozzle are treated when
the cavitation number, σ = 0.1, and the computation result is compared with
Guoyi Peng, Kunihiro Okada, Congxin Yang, Yasuyuki experimental data The result reveals that cavitation occurs initially at theSubmerged water jet, cavitation, bubble dynamics,
Oguma, Seiji Shimizu
entrance of orifice and bubble cloud develops gradually while flowing
two-phase flow, computational fluid dynamics
downstream along the shear layer. Developed bubble cloud breaks up andthen sheds downstream periodically near the sheath exit. The pattern ofcavitation cloud shedding evaluated by simulation agrees experimental one,and the possibility to capture the unsteadily shedding of cavitation clouds isdemonstrated. The decay of core velocity in cavitating jet is delayed greatlycompared to that in no-activation jet, and the effect of the nozzle sheath isdemonstrated.

75-84

85-94

Historical Perspective on Fluid Machinery Flow
Optimization in an Industry

Unsteady Wet Steam Flow Measurements in a LowPressure Test Steam Turbine

Akira Goto

Chongfei Duan, Koji Ishibashi, Shigeki Senoo, Ilias
Bosdas, Michel Mansour, Anestis I. Kalfas, Reza S.
AbhariAn experimental study is conducted for unsteady wet steam flow in a fourstage low-pressure test steam turbine. The measurements are carried out atoutlets of the last two stages by using a newly developed fast response
aerodynamic probe. This FRAP-HTH probe (Fast Response Aerodynamic Probe- High Temperature Heated) has a miniature high-power cartridge heater with Steam turbine, Wet steam, Unsteady flow
an active control system to heat the probe tip, allowing it to be applied to wet measurement, Low-pressure stage
steam measurements. The phase-locked average results obtained with asampling frequency of 200 kHz clarify the flow characteristics, such as theblade wakes and secondary vortexes, downstream from the individual
rotational blades in the wet steam environment.
A method of optimization design for the blade profile of a centrifugal impeller
by controlling velocity distribution is presented, and a plenum fan issuccessfully designed. This method is based on the inner flow calculation
inside the centrifugal impeller, and is related to the distribution of relative
velocity. The results show that after optimization, the boundary layer
velocity distribution, blade profile, static pressure,separation on the suction surface has been inhibited and the stability ofstatic pressure efficiency
plenum fan is improved. The flow at the impeller outlet is also studied, and thejet-wake pattern at the impeller outlet is improved obviously by optimization.
The calculation result shows that the static pressure and static pressure
efficiency can be increased by 15.4% and 21.4% respectively.

95-106

Optimization of Blade Profile of a Plenum Fan

Lin Wu, Hua-Shu Dou, Yikun Wei, Yongning Chen,
Wenbin Cao, Cunlie Ying

Page

Title

Author

107-118

119-128

129-136

137-142

Numerical And Experimental Study Of Single stage
And Multistage Centrifugal Mixed Flow Submersible
Borewell Pumps

Numerical Analysis of Unsteady Cavitating Flowaround Balancing Drum of Multistage Pump

Performance Research of Counter-rotating Tidal
Stream Power Unit

Numerical Analysis of Flow in Radial Turbine(Effects of Nozzle Vane Angle on Internal Flow)

Fluid-dynamic design of fluid machinery had heavily relied on empiricism andexperimental observations for many years. Since 1980s, thanks to theadvancements in Computational Fluid Dynamics (CFD), a variety of flow
physics have been revealed. The contribution by CFD is indispensable;
however, the challenge is required not only on the advancements in CFD
Design technology, Physical insight, Inverse design,technologies but also innovation of “ design (optimization) technologies ”
Numerical optimization, Multi-objective, Adjoint
because of the complex interactions between 3-D flow fields and the complex
3-D flow passage configurations, etc. This paper presents historical perspectiveon fluid machinery flow optimization in an industry with some messages forthe future.

Abstract

Keywords

C. Murugesan, Dr. R. Rudramoorthy

This paper focuses on the single stage and multistage performance
characteristics of centrifugal mixed flow submersible borewell pump. This study
reveals that the performance of single stage pump is higher than that ofmultistage pumps. The head, input power and efficiency of single stage pump
are higher than the per stage head, per stage input power and efficiency ofmultistage pumps. This study is divided into three parts. In the first part, fiveprototype pumps were made in single stage and multistage construction andthe performance tests were conducted. In the second part, numericalvelocity distribution, blade profile, static pressure,validation has been done for different turbulence models and grid sizes. kstatic pressure efficiency
Omega SST model has been selected for the performance simulation and wasvalidated with the performance of the test pump with static pressure tappings.In the third part, single and three stage pump performance were simulated
numerically and compared with experimental results. The detailed analysis ofpressure and velocity distributions reveals the difference in performance of
single and three stage pump, due to non-uniform flow and difference inaveraged flow velocities at the subsequent impeller inlets except the 1st stage
impeller inlet.

Milan Sedlár, Tomáš Krátký, Patrik Zima

This work presents the numerical investigation of an unsteady cavitating flow
around a balancing drum of a multistage pump. The main attention is focusedon the cavitation phenomena, which occur in the rear part of the drum
clearance, cause the erosion of the drum material and influence the pressure
cavitation erosion, numerical simulation, multistage
losses and the flow rate through the clearance. The one-way coupling of thepump, balancing drum
URANS equations and the full Rayleigh-Plesset equation is employed toanalyse the flow field as well as the dynamics of cavitating bubbles. The
numerical simulations show that the erosion processes are highly influenced byshaft vibrations, namely by periodic deformations of the annular clearance intime. The calculated results are verified by erosion tests on a real pump.

An experimental investigation was carried out to improve the performance ofa counter-rotating type horizontal-axis tidal stream power unit. Front and rear
blades were designed separately based on modified blade element
momentum (BEM) theory, and their performances at different conditions ofcounter-rotating, tidal turbine, power coefficient, wind
Xuesong Wei, Bin Huang, Pin Liu, Toshiaki Kanemoto blade tip speed ratio were measured in a wind tunnel. Three different groups
tunnel, BEM
of blades were designed successively, and the results showed that Group3
possessed the highest power coefficient of 0.44 and was the most satisfactorymodel. This experiment shows that properly increasing diameter and reducing
chord length will benefit the performance of the blade.
Variable Geometry System (VGS) is widely applied to the nozzle vane for theradial inflow turbine constituting automotive turbochargers for the purpose of
optimizing the power output at each operating condition. In order to improve
the performance of radial turbines with VGS, it is necessary to clarify the
influences of the setting angle of nozzle vane on the internal flow of radial
turbine. However, the experimental measurements are considered to bedifficult for the flow in radial turbines because of the small size and the highKenta OTSUKA, Tomoya KOMATSU, Hoshio TSUJITA,
Radial Turbine, Numerical Analysis, Turbocharger,
rotational speed. In the present study, the numerical calculations were carried
Satoshi YAMAGUCHI, Akihiro YAMAGATA
Secondary Flowout for the flow in the radial turbine at three operating conditions by applying
the corresponding nozzle vane exit angles, which were set up in theexperimental study, as the inlet boundary condition. The numerical results
revealed the characteristic flow behaviors at each operating condition.

In this study, a method for the multi-objective optimization of an impeller fora centrifugal compressor using fluid-structure interaction (FSI) and response
surface method (RSM) was proposed. Numerical simulation was conductedusing ANSYS CFX and Mechanical with various configurations of impeller
geometry. Each design parameter was divided into 3 levels. A total of 15
design points were planned using Box-Behnken design, which is one of the143-149

A Study on the Multi-Objective Optimization of
Impeller for High-Power Centrifugal Compressor

Hyun-Su Kang, Youn-Jea Kim

design of experiment (DOE) techniques. Response surfaces based on the
results of the DOE were used to find the optimal shape of the impeller. Two

Centrifugal compressor, Shape optimization,
Response surface method, Isentropic efficiency, Fluid-

objective functions, isentropic efficiency and equivalent stress were selected.
structure interaction
Each objective function is an important factor of aerodynamic performanceand structural safety. The entire process of optimization was conducted using
the ANSYS Design Xplorer (DX). The trade-off between the two objectives wasanalyzed in the light of Pareto-optimal solutions. Through the optimization,
the structural safety and aerodynamic performance of the centrifugal
compressor were increased.

150-158

Parametric Optimization of Vortex Shedder based on
Combination of Gambit, Fluent and iSIGHTSu Myat Nyein, He Xu, Hongpeng YU

In this paper, a new framework that works the automatic execution with lessdesign cycle time and human intervention bottlenecks is introduced to
optimize the vortex shedder design by numerical integration method. This
framework is based on iSIGHT combined with the pre-processor GAMBIT, andflow analysis software FLUENT. Two vortex shedders, circular with slit andtriangular- semi circular cylinder, are employed as the designed models to be Optimization, vortex shedder, how to integrate theoptimized, and DOE driver is used for optimization. According to the essential GAMBIT and FLUENT to iSIGHT
properties of a vortex shedder, it has found that the best diameters are 30mm
for circular cylinder with slit and 30 to 35 mm for tri-semi cylinder. For slit
ratio, 0.1 and 0.15 are the optimized values for circular with slit and tri-semi
cylinder respectively. And it is found that these optimal results generated by
DOE automated design cycle are in well agreement with the experiment.

159

Erratum: Numerical Analysis of Damping Effect ofLiquid Film on Material in High Speed Liquid Droplet
Impingement

Hirotoshi Sasaki, Naoya Ochiai, Yuka Iga

An error has been found in the footnote in Vol. 9 (2016) No. 1 (JanuaryMarch) p. 57

Vol. 9, No.
2, AprilJune, 2016

160-168

169-174

Dynamic Response of Blade Surface Cavitation

Performance and Flow Condition of Cross-Flow Wind
Turbine with a Symmetrical Casing Having Side
BoardsMasakazu Toyoshima, Kimiya Sakaguchi, Kota
Tsubouchi, Hironori Horiguchi, Kazuyasu Sugiyama

Toru Shigemitsu, Junichiro Fukutomi, Masaaki
Toyohara

In high speed turbopumps, cavitation occurs and often causes the flow
instabilities such as cavitation surge and rotating cavitation. The occurrence of
these cavitation instabilities is considered to relate to dynamic characteristicsof the cavitation, which are modelled using a cavitation compliance and amass flow gain factor. Various types of cavitation such as a blade surface
Cavitation, Hydrofoil, Dynamic Characteristics,
cavitation, a tip leakage vortex cavitation, and a backflow vortex cavitation
Experimentoccur at the same time in the inducer and the dynamic characteristics of eachcavitation have not been clarified yet in experiments. Focusing on the bladesurface cavitation as one of fundamental cavitation, we investigated the
dynamic characteristics of the blade surface cavitation on a flat plate hydrofoil
in experiments in the present study.
A cross-flow wind turbine has a high torque coefficient at a low tip speed
ratio. Therefore, it is a good candidate for use as a self-starting turbine.
Furthermore, it has low noise and excellent stability; therefore, it has attracted
attention from the viewpoint of applications as a small wind turbine for an
urban district. However, its maximum power coefficient is extremely low (10 %)as compared to that of other small wind turbines. In order to improve theperformance and flow condition of the cross-flow rotor, the symmetricalcasing with a nozzle and a diffuser are proposed and the experimental
Cross-flow wind turbine, Power coefficient, Torqueresearch with the symmetrical casing is conducted. The maximum power
coefficient, Symmetrical casing, Numerical analysis
coefficient is obtained as Cpmax = 0.17 in the case with the casing andCpmax=0.098 in the case without the casing. In the present study, the power
characteristics of the cross-flow rotor and those of the symmetrical casing with
the nozzle and diffuser are investigated. Then, the performance and internal
flow patterns of the cross-flow wind turbine with the symmetrical casings areclarified. After that, the effect of the side boards set on the symmetrical casing
is discussed on the basis of the analysis results.

Contra-rotating rotors have been adopted for some of the cooling fans tomeet the demand for the high pressure and large flow rate. Therefore, it isimportant to clarify its inlet and outlet flows by experiments for the highperformance and stable operation. PIV measurements were conducted at the
PIV Measurement of Inlet and Outlet Flow of ContraCooling fan, PIV measurement, Internal flow, Contra175-181
Toru Shigemitsu, Hiroaki Fukuda, Junichiro Fukutomi design and partial flow rates. In the present paper, the inlet and outlet flow
Rotating Small-Sized Cooling Fan
rotating rotor
conditions of the contra-rotating small-sized cooling fan with a 40mm squarecasing are studied by using PIV measurement. Furthermore, improvements ofthe flow condition and design guideline to increase the performance werediscussed based on the experimental results.

182-193

Effects of load variation on a Kaplan turbine runner

K. Amiri, B. Mulu, M.J. Cervantes, M. Raisee

Page

Title

Author

194-204

Rotordynamic Characteristics of Floating Ring Seals in
Rocket Turbopumps

Yuichiro Tokunaga, Hideyuki Inoue, Jun Hiromatsu,
Tetsuya Iguchi, Yasuhiro Kuroki, Masaharu Uchiumi

Introduction of intermittent electricity production systems like wind and solar
power to electricity market together with the deregulation of electricity
markets resulted in numerous start/stops, load variations and off-design
operation of water turbines. Hydraulic turbines suffer from the varying loads
exerted on their stationary and rotating parts during load variations since they
are not designed for such operating conditions. Investigations on part load
operation of single regulated turbines, i.e., Francis and propeller, proved theformation of a rotating vortex rope (RVR) in the draft tube. The RVR induces
pressure pulsations in the axial and rotating directions called plunging androtating modes, respectively. This results in oscillating forces with two different
Kaplan turbine, Runner pressure measurement, Loadfrequencies on the runner blades, bearings and other rotating parts of thevariations, Rotating vortex rope formation, Rotating
turbine. This study investigates the effect of transient operations on thevortex rope mitigationpressure fluctuations exerted on the runner and mechanism of the RVR
formation/mitigation. Draft tube and runner blades of the Porjus U9 model, aKaplan turbine, were equipped with pressure sensors for this purpose. The
model was run in off-cam mode during different load variations. The results
showed that the transients between the best efficiency point and the highload occurs in a smooth way. However, during transitions to the part load a
RVR forms in the draft tube which induces high level of fluctuations with two
frequencies on the runner; plunging and rotating mode. Formation of the RVR
during the load rejections coincides with sudden pressure change on therunner while its mitigation occurs in a smooth way.
Abstract

Keywords

Floating ring seals offer an opportunity to reduce leakage flows significantly inrotating machinery. Accordingly, they have been applied successfully torotating machinery within the last several decades. For rocket turbopump
applications, fundamental behavior and design philosophy have been revealed.
However, further work is needed to explore the rotordynamic characteristics
associated with rotor vibrations. In this study, rotordynamic forces for floating
ring seals under rotor's whirling motions are calculated to elucidate
rotordynamic characteristics. Comparisons between numerical simulation
results and experiments demonstrated in our previous report are carried out. cryogenics, shaft-seal system, FRS, floating ring seal,
The three-dimensional Reynolds equation is solved by the finite-difference
dynamic characteristics, rotordynamic coefficientmethod to calculate hydrodynamic pressure distributions and the leakage flow
rate. The entrance loss at the upstream inlet of the seal ring is calculated toestimate the Lomakin effect. The friction force at the secondary seal surface isalso considered. Numerical simulation results showed that the rotordynamic
forces of this type of floating ring seal are determined mainly by the friction
force at the secondary seal surface. The seal ring is positioned almost
concentrically relative to the rotor by the Lomakin effect. Numericalsimulations agree quite well with the experimental results.

205-212

Efficiency Increase and Input Power Decrease ofConverted Prototype Pump Performance

Masao Oshima

The performance of a prototype pump converted from that of its model pumpshows an increase in efficiency brought about by a decrease in friction loss. As
the friction force working on impeller blades causes partial peripheral motion
on the outlet flow from the impeller, the increase in the prototype's efficiency
causes also a decrease in its input power. This paper discusses results ofanalyses on the behavior of the theoretical head or input power of a
Performance conversion, Model pump, Efficiency
prototype pump. The equation of friction-drag coefficient for a flat plate wasapplied for the analysis of hydraulic loss in impeller blade passages. It wasincrease, Input power decrease, Scale effectrevealed that the friction-drag of a flat plate could be, to a certain degree,
substituted for the friction drag of impeller blades, i.e. as a means foranalyzing the relationship between a prototype pump's efficiency increase andinput power decrease.

213-221

CFD and surrogates-based inducer optimization

Tomáš Krátký, Lukáš Zavadil, Vít Doubrava222-228

Hydraulic Model Test of a Floating Wave Energy
Converter with a Cross-flow Turbine

Sangyoon Kim, Byungha Kim, Joji Wata, Young-Ho
Lee

Exergetic analysis for optimization of a rotating
229-236 equilateral triangular cooling channel with staggeredsquare ribs

Vol. 9, No.
3, JulySeptember, 2016237-244245-255

256-264

Analysis on Characteristic of Pressure Fluctuation in
Hydraulic Turbine with Guide Vane

Study on the Alternating Flow Hydraulics and Its New
Potential Application in the Geotechnical Testing Field

Design and performance research of a mixed-flow
submersible deep well pump

Due to the nature of cavitation numerical analyses, computational optimizationof a pump with respect to the cavitation properties is extremely demanding. In
this paper it is shown how a combination of Transient Blade Row (TBR)
method and some simplifications can be used for making the optimization
process more efficient and thus possible on current generation of hardware.
The aim of the paper is not the theory of hydraulic design. Instead, thepractical aspects of numerical optimization are shown. This is done on an
Design Optimization, CFD, Cavitation, Inducer, TBR,
example of a radial pump and a combination of ANSYS CFX, ANSYS software ANSYS CFX
tools and custom scripts is used. First, a comparison of TBR and fully-transient
simulation is made. Based on the results, the TBR method is chosen and aparametric model assembled. Design of Experiment (DOE) table is computed
and the results are used for sensitivity analysis. As the last step, the final
design is created and computed as fully-transient. In conclusion, the results are
discussed.
Almost 70% of the earth is covered by the ocean. Extracting the power
available in the ocean using a wave energy converter has been seen to be
eco-friendly and renewable. This study focuses on developing a method foranalyzing a wave energy device that uses a cross-flow turbine. The motion of
Ocean energy, Floating wave energy converter(WEC),
the ocean wave causes an internal bi-directional flow of water and the crossCross-flow turbine, Power take-off system(PTO),
flow turbine is able to rotate in one direction. This device is considered of
Double-hull structure, Hydraulic model test
double-hull structure, and because of this structure, sea water does not comeinto contact with theturbine. Due to this, the problem of befouling on theturbine is avoided. This study shows specific relationship for wave length andseveral motions.

Mi-Ae Moon, Kwang-Yong Kim

Exergetic analysis was introduced in optimization of a rotating equilateraltriangular internal cooling channel with staggered square ribs to maximize thenet exergy gain. The objective function was defined as the net exergy gain
considering the exergy gain by heat transfer and exergy losses by friction andheat transfer process. The flow field and heat transfer in the channel wereanalysed using three-dimensional Reynolds-averaged Navier-Stokes equations
under the uniform temperature condition. Shear stress transport turbulencemodel has been selected as a turbulence closure through the turbulencemodel test. Computational results for the area-averaged Nusselt number were
Exergetic analysis, Optimization, Cooling channel,
validated compared to the experimental data. Three design variables, i.e., theHeat transfer enhancement, Ribs
angle of rib, the rib pitch-to-hydraulic diameter ratio and the rib width-tohydraulic diameter ratio, were selected for the optimization. The optimization
was performed at Reynolds number, 20,000. Twenty-two design points wereselected by Latin hypercube sampling, and the values of the objective function
were evaluated by the RANS analysis at these points. Through optimization,
the objective function value was improved by 22.6% compared to that of thereference geometry. Effects of the Reynolds number, rotation number, andbuoyancy parameter on the heat transfer performance of the optimum design
were also discussed.

FengXia Shi, JunHu Yang, XiaoHui Wang

An unsteady three-dimensional simulation based on Reynolds time-averaged
governing equation and RNG k-ε turbulence model, was presented for pumpas-turbine, the pressure fluctuation characteristic of hydraulic turbine withguide vane was obtained. The results show that the time domains of pressure
fluctuation in volute change periodically and have identical cycles. In volute
Hydraulic turbine with guide vane, Volute tongue,
tongue and inlet pressure fluctuations are light, while in dynamic and static
Dynamic and static coupling interface, Pressure
coupling interface pressure fluctuations are serious; In impeller blade region
fluctuation
the pressure fluctuation of pressure surface are lighter than that of suction
surface. The dominant frequencies of pressure fluctuation concentrate in low
frequency region, and concentrate within 2 times of the blade passing
frequency.

Yong Sang, Ying Han, Fuhai Duan

The alternating flow hydraulics (AFH) had demonstrated the unique features in
the past. One of the most well-known inventions was the hydraulic machinegun synchronizer, which had become the standard equipment of airplane
during World War I. The studies on the AFH between 1960 and 1980 had
trigged many researchers' interests and reached the summit. The
disadvantages of the AFH like low efficiency and cooling difficulty had
prevented the further development. Few people are engaged in studying the
AFH at present. However, the unique characteristics of the AFH inspire theresearchers to continuously explore the new special suitable applications. The
overviews of the AFH and the new potential application in the geotechnicaltesting field have been discussed in this paper. First, the research results of the alternating flow hydraulics, hydraulic transmission,
AFH in the past have been summarized. Then, the classifications of the AFH
dynamic trixial instrument
have been introduced in detail according to the working principle, the numberof hydraulic transmission pipelines and the mode of input energy. The
advantages and the disadvantages of the AFH have been discussed. A novel
potential suitable application in the soil test field has been presented at last.
The detailed designing ideas of a new dynamic trixial instrument have been
given, which will be a more innovational and energy-saving plan according to
the current studies. A series of simulation experiments have been done. The
simulation results show that the proposed scheme for the new dynamic trixial
instrument is feasible. The paper work will also give some inspirations in thereciprocating motion control system.

Qihua Zhang, Yuanhui Xu, Li Cao, Weidong Shi,
Weigang Lu

To meet the demand of higher handling capacity, a mixed-flow submersible
deep well pump was designed and tested. The main hydraulic components are
made of plastics, which is free of erosion, light-weight, and environmentfriendly. To simplify plastic molding process, and to improve productivity, anaxial-radial guide vane was proposed. To clarify its effect on the performance,a radial guide vane and a space guide vane are developed as well. By
comparison, the efficiency of the pump equipped with the axial-radial guide
submersible deep well pump, mixed-flow, axial-radial
vane is higher than the radial guide vane and is lower than the space guide
guide vane, design
vane, and its high efficiency range is wide. The static pressure recovery of theaxial guide vane is a bit lower than the space guide vane, but it is much larger
than the radial guide vane. Taking the cost and molding complexity into
consideration, the axial-radial guide vane is much economic, promoting its
popularity for the moderate and high specific speed submersible deep well
pumps.

Energy systems working coherently in different conditions may not have a
specific design which can provide optimal performance. A system working fora longer period at lower efficiency implies higher energy consumption. In thiseffort, a methodology demonstrated by a jet pump design and optimization
via numerical modeling for fluid dynamics and implementation of anevolutionary algorithm for the optimization shows a reduction incomputational costs. The jet pump inherently has a low efficiency because of
improper mixing of primary and secondary fluids, and multiple momentum
and energy transfer phenomena associated with it. The high fidelity solutions Ensemble of surrogates, Multi-objective optimization,
Energy Efficient Design of a Jet Pump by Ensemble of Afzal Husain, Arihant Sonawat, Sarath Mohan, Abdus
265-276were obtained through a validated numerical model to construct anPareto-optimal designs, Evolutionary computation,
Surrogates and Evolutionary Approach
Samadapproximate function through surrogate analysis. Pareto-optimal solutions for Efficiency enhancement, Jet pump
two objective functions, i.e., secondary fluid pressure head and primary fluidpressure-drop, were generated through a multi-objective genetic algorithm.
For the jet pump geometry, a design space of several design variables wasdiscretized using the Latin hypercube sampling method for the optimization.
The performance analysis of the surrogate models shows that the combined
surrogates perform better than a single surrogate and the optimized jet pumpshows a higher performance. The approach can be implemented in otherenergy systems to find a better design.

277-286

Numerical Prediction of Inlet Recirculation in Pumps

Andrej Lipej, Duško Mitruševski

Page

Title

Author287-299

Numerical Simulation of Erosive Wear on an Impact
Sprinkler Nozzle Using a Remeshing Algorithm

Yuncheng Xu, Haijun Yan

300-306

A Twin Impulse Turbine for Wave Energy Conversion-The Performance under Unsteady Airflow-

M M Ashraful Alam, Hideki Sato, Manabu Takao,
Shinya Okuhara, Toshiaki Setoguchi

307-312

Wells Turbine for Wave Energy Conversion -Effect ofTrailing Edge Shape-313-324

Centrifugal Impeller Blade Shape Optimization
Through Numerical Modeling325-331

Free Surface Vortex in a Rotating Barrel with Rods ofDifferent Heights

Experimental study on the performance of a332-337 turbocompound diesel engine with variable geometry
turbocharger

Vol. 9, No.
4,
OctoberDecember,
2016

Katsuya Takasaki, Tomohiro Tsunematsu, Manabu
Takao, M M Ashraful Alam, Toshiaki Setoguchi

The development of heavy-duty process pumps, usually based on various
design criteria, depends on the pump's application. The most important criteria
are Q-H, efficiency and NPSH characteristics. Cavitation due to inlet
recirculation is not often one of the design criteria, although many problems
in pump operation appear because of inlet recirculation, when the operation
range is from 0.5-0.8 Qopt.
The present paper shows that steady state CFD analysis of inlet recirculation
process pump, CFD, cavitation, flow recirculation
can give quite good results for the design of new hydraulic shapes, whichhave been developed to expand operating range and to minimize the harmful
influence of recirculation at part load. In this paper, the structures of inlet
recirculation are presented, as well as detailed shapes of vortices between theblades for various operating regimes, axial velocity distribution at the impeller
inlet, the experimental results of NPSH and efficiency characteristics of an
existing and newly designed pump.
Abstract

Keywords

In China, agricultural irrigation water often contains a lot of suspended
sediment which may cause the nozzle wear. In this study, a new numericalsimulation combing the Discrete Phase Model and a remeshing algorithm wasconducted. The geometric boundary deformation caused by the erosion wear,
was considered. The weight loss of the nozzle, the node displacement and theflow field were investigated and discussed. The timestep sensitivity analysis
showed that the timestep is very critical in the erosion modeling due to therandomness and the discreteness of the erosion behavior. Based on theRemeshing algorithm, erosion wear, impact sprinkler
simulation results, the major deformation of the boundary wall due to thenozzle, CFD, discrete phase modelerosion was found at the corners between outlet portion and contraction
portion. Based on this remeshing algorithm, the simulated erosion weight lossof the nozzle is 4.62% less compared with the case without boundary
deformation. The boundary deformation changes the pressure and velocity
distribution, and eventually changes the sediment distribution inside thenozzle. The average turbulence kinetic energy at the outlet orifice is found to
decrease with the erosion time, which is believed to change the nozzle’s spray
performance eventually.
A twin unidirectional impulse turbine for wave energy conversion has beensuggested in our previous study, and the performance under unsteady flow
has been investigated by quasi-steady analysis. In the present study, theperformance of twin impulse turbine under unsteady flow condition has been
CFD, Fluid machinery, Oscillating water column, Twininvestigated by unsteady analysis of Computational fluid dynamics. As a result,
impulse turbine, Wave energy conversion
the mean efficiency of twin unidirectional impulse turbine under unsteady flow
is lower than the maximum efficiency of unidirectional impulse turbine.
Moreover, it is verified that airflow goes backward in the reverse turbine in low
flow rates.
The present study reported of the use of special shaped blade to reduce thedifference in pressure across the Wells turbine for wave energy conversion. The
blade profile was composed of NACA0020 airfoils and trailing edge wasnotched like chevron. Experiments were performed investigating the influenceof trailing edge shape on the turbine performance. Four notch depths were
Chevron, Fluid machinery, Oscillating water column,
used to investigate the effect of depth of cut on the turbine performance. As Wave energy conversion, Wells turbine
results, by placing a notch-cut at the trailing edge of the blade, it was possible
to reduce the pressure difference across the turbine without lowering theefficiency. In addition, the pressure difference substantially reduced at aconstant rate with the increase of the cut ratio.

Surrogate model based shape optimization methodology to enhance
performance of a centrifugal pump has been implemented in this work. Design
variables, such as blade number and blade angles defining the pump impeller
blade shape were selected and a three-level full factorial design approach wasused for efficiency enhancement. A threedimensional simulation using
Centrifugal impeller, Optimal design, Blade number,
Reynolds-averaged Navier Stokes (RANS) equations for the performance
Sayed Ahmed Imran Bellary, Abdus Samad
Blade angles, Multiple Surrogate models, Hydraulicanalysis was carried out after designing the geometries of the impellers at theefficiency
design points. Standard k-ε turbulence model was used for steadyincompressible flow simulations. The optimized impeller incurred lower losses
by shifting the trailing edge towards the impeller pressure side. It is observedthat the surrogates are problem dependent and most accurate surrogate does
not deliver the best design always.
A bathtub vortex above the outlet of a rotating barrel is simulated. By
analyzing the Ekman layer theory, it can be found that the main flow
circulation is inversely proportional to the thickness of Ekman layer. The thicker
Zhang Xiaoyue, Zhang Min, Chen Wanyu, Yang Fan, the Ekman boundary layer, the weaker the rotational strength and the shorter bathtub vortex, Ekman layer, tangential velocity, air
Guo Xueyanof the length of gas core is. According to this law, models of barriers with rods core, circulationof different heights are established. The reduction of air-core length in this air
entrainment vortex and weakening the strength of rotation field wereachieved.

Yong Yin, Zhengbai Liu, Weilin Zhuge, Rongchao
Zhao, Yanting Zhao, Zhen Chen, Jiao Mi

Turbocompounding is a key technology to satisfy the future requirements ofdiesel engine's fuel economy and emission reduction. A turbocompound diesel
engine was developed based on a conventional 11-Liter heavy-duty diesel
engine. The turbocompound system includes a power turbine, which isinstalled downstream of a Variable Geometry Turbocharger (VGT) turbine. The
Diesel engine, Turbocompounding, Variable Geometry
impacts of the VGT rack position on the turbocompound engine performance
Turbocharger (VGT), Fuel economy
were studied. An optimal VGT control strategy was determined. Experimental
results show that the turbocompound engine using the optimal VGT control
strategy achieves better performance than the original engine under all fullload operation conditions. The averaged and maximum reductions of thebrake specific fuel consumption (BSFC) are 3% and 8% respectively.

Vol. 9, No.
4,
OctoberDecember,Information on the surge behaviors and stall stagnation boundaries for a nine-stage axial flow
compressor are summarized on the basis of analytical data in comparison with those for asingle-stage one, with attention to the pressure ratio effect. The general trends of the surge
loop behaviors of the pressure-mass flow are similar for both compressors including the fact

2016

that the subharmonic surges tend to appear very near the stall stagnation boundaries.
With respect to the nine-stage compressor, however, the mild loops in the subharmonic surges
tend to be very small in size relative to the deep loops, and at the same time, insufficient
surge recovery phenomenon, which is a kind of subharmonic surge, appears also far from thestagnation boundary for relatively short delivery flow-paths. The latter is found to be a rear-

338-353

A Comparison of Surge Behaviors in Multi-Stage andSingle-Stage Axial Flow Compressors

Nobuyuki Yamaguchi

stage surge caused by unstalling and re-stalling of the rear stages with the front-stages kept in

Fluid Machine, Axial Flow Compressor, Surge,

stall in the stalled condition of the whole compressor, which situation is caused by stage-wise

Analytical Simulation, Frequency, Fluid Dynamics

mismatching in the bottom pressure levels of the in-stall multi-stage compressor.
The fundamental information on the stall stagnation boundaries is given by a group of
normalized geometrical parameters including relative delivery flow-path length, relative suction
flow-path length, and sectional area-pressure ratio, and by another group of normalized
frequency parameters including relative surge frequencies, modified reduced resonancefrequencies, and modified reduced surge frequencies. Respective groups of the normalized
parameters show very similar tendency of behaviors for the nine-stage compressor and thesingle-stage compressor.
The modified reduced resonance frequency could be the more reasonable parameter

354-361362-369

370-381382-393

Performance Study of Thrust Control Unit with the
Various Geometric Shapes

Optimal Design of Two-Dimensional Cascade with
Shock-Free Inflow Criterion

Optimization of a Single-Channel Pump Impeller for
Wastewater Treatment

Numerical Investigation of CuO-Water Nanofluid Flowand Heat Transfer across a Heated Square Cylinder

Kyoung-Ryun Kim, Jong-Ho Park

This study aims to identify aerodynamic characteristics of the ramp tab, amechanical deflector, by conducting a non-combustive experiment using
compressed air and supersonic flow test equipment. With the ramp tabs
installed symmetrically and asymmetrically on the outlet of the supersonic
Mechanical deflector, Drag coefficients, Flow field,
nozzle, the structure of the flow field, the thrust spoilage, the thrust deviation
Pressure distribution, Fluid flow characteristics
angle, and the lift/drag coefficients were derived and analyzed. The results
show that the asymmetrically-installed ramp tabs are advantageous relative tothe symmetrically-installed tabs in terms of the performance of thrust vector
control, thrust deviation angle, and lift coefficient.

The shock-free inflow criterion applied in the development of two-dimensionalcascade for turbomachinery design. The developed cascade analysis withpotential flow calculation through a panel method has been used todetermine the shock-free inflow condition. The combination between cascade
analysis and PSO (particle swarm optimization) algorithm provides an
Abdul Muis, Priyono Sutikno, Aryadi Soewono, Firman
Shock-free inflow, cascade, particle swarm
opportunity to develop a diagram of a two-dimensional parameter cascade at
Hartonooptimization, surface vorticity, panel method
various airfoil shapes. Analytical equations have been derived from thediagram that will facilitate the turbomachinery designer in applying the shockfree inflow criterion on their developed cascade. This method has been used
to develop the very low head axial hydraulic turbine and provides excellent
results of numerical and actual prototype performances.

Joon-Hyung Kim, Bo-Min Cho, Youn-Sung Kim,
Young-Seok Choi, Kwang-Yong Kim, Jin-Hyuk Kim,
Yong Cho

Lotfi Bouazizi, Saïd Turki

As a single-channel pump is used for wastewater treatment, this particularpump type can prevent performance reduction or damage caused by foreign
substances. However, the design methods for single-channel pumps aredifferent and more difficult than those for general pumps. In this study, adesign optimization method to improve the hydrodynamic performance of asingle-channel pump impeller is implemented. Numerical analysis was carriedout by solving three-dimensional steady-state incompressible Reynoldsaveraged Navier-Stokes equations using the shear stress transport turbulencemodel. As a state-of-the-art impeller design method, two design variables
Single-channel pump, Wastewater treatment, Design
related to controlling the internal cross-sectional flow area of a single-channel optimization, Computational Fluid Dynamics, Crosspump impeller were selected for optimization. Efficiency was used as thesectional area control, Bezier curve
objective function and was numerically assessed at twelve design points
selected by Latin hypercube sampling in the design space. An optimization
process based on a radial basis neural network model was conductedsystematically, and the performance of the optimum model was finallyevaluated through an experimental test. Consequently, the optimum model
showed improved performance compared with the base model, and theunstable flow components previously observed in the base model were
suppressed remarkably well.
Flow over a bluff body is an attractive research field in thermal engineering. In
the present study, laminar flow over a confined heated square cylinder using
CuO-Water nanofluid is considered. Unsteady two-dimensional Navier-Stokes
and energy equations are solved numerically using finite volume method(FVM). Recent correlations for the thermal conductivity and viscosity ofnanofluids, which are function of nanoparticle volume fraction, temperature
CuO-Water nanofluid, heated square cylinder,and nanoparticle diameter, have been employed. The results of numericalthermophysical properties, buoyancy force, heatsolution are obtained for Richardson number, nanoparticle volume fractionstransfer enhancement
and nanoparticle diameters ranges of 0-1, 1-5% and 30-100 nm respectively
for a fixed Reynolds number of Re = 150. At a given volume concentration,
the investigations reveal that the decreasing in size of nanoparticles produces
an increase in heat transfer rates from the square cylinder and a decrease inamplitude of the lift coefficient. Also, the increment of Nusselt number is more
pronounced at higher concentrations and higher Richardson numbers.

Page

1-8

9-18

19-29

Title

Author

Abstract

Keywords

Bifurcation refers to wye division of penstock to divide the flow symmetricallyor unsymmetrically into two units of turbine for maintaining economical,
technical and geological substrates.
Particularly, water shows irrelevant behavior when there is a sudden change inflow direction, which results into the transition of the static and dynamic
behavior of the flow. Hence, special care and design considerations are
required both hydraulically and structurally. The transition induced losses andextra stresses are major features to be examined.
The research on design and analysis of bifurcation is one of the oldest topics
Vertical Axis Wind Turbine, Duct Flow Power
Computational Design of Bifurcation: A Case Study of Ravi Koirala, Sailesh Chitrakar, Hari Prasad Neopane, related to R&D of hydro-mechanical components for hydropower plants. As
Generation, Wind Energy, Butterfly Wind Turbine,
Darundi Khola Hydropower Project
Balendra Chhetri, Bhola Thapa
far as the earlier approaches are concerned, the hydraulic designs were
Computational Fluid Dynamics
performed based on graphical data sheet, head loss considerations and themechanical analysis through simplified beam approach.
In this paper, the multi prospect approach for design of Bifurcation,
incorporating the modern day's tools and technology is identified. The
hydraulic design of bifurcation is a major function of dynamic characteristics ofthe flow, which is performed with CFD analysis for minimum losses and better
hydraulic performances. Additionally, for the mechanical design, a simplified
conventional design method as pre-estimation and Finite Element Method fora relevant result projections were used.

Employing rotating vaneless diffuser to enhance theperformance of plenum fan

Experimental and Numerical Studies on the Possibilityof Duct Flow Low-power Generation Using a Butterfly
Wind Turbine

Hua-Shu Dou, Lin Wu, Yikun Wei, Yongning Chen,
Wenbin Cao, Cunlie Ying

Numerical simulation is carried out for flow characteristics in a plenum fan andthe influence of the diameter ratio of the rotating vaneless diffuser on theperformance of plenum fan is analyzed. The diameter ratio of the rotating
vaneless diffuser employed is from 1.03 to 1.3. The research results show that Plenum fan, rotating vaneless diffuser, static pressure,
the rotating vaneless diffuser is able to enhance the performance of plenum
efficiency
fan. It is found that there is significant improvement in static pressure andefficiency at the diameter ratio of 1.05 at high flow coefficients, while theoptimal diameter ratio is 1.2 at rated and low flow coefficient.

Yutaka Hara, Shohei Kogo, Katsuhiro Takagaki,
Makoto Kawanishi, Takahiro Sumi, Shigeo Yoshida

An objective of this study is to demonstrate the validity of using a small windturbine to recover the fluid energy flowing out of an exhaust duct for thegeneration of power. In these experiments, a butterfly wind turbine of avertical axis type (D = 0.4 m) is used. The output performance is measured at
Vertical Axis Wind Turbine, Duct Flow Powervarious locations relative to the exit of a small wind tunnel (W = 0.65 m),
Generation, Wind Energy, Butterfly Wind Turbine,
representing the performance expected in an exhaust duct flow. TwoComputational Fluid Dynamics
dimensional numerical analysis qualitatively agrees with the experimental
results for the wind turbine power coefficient and rate of energy recovery.
When the turbine is far from the duct exit (more than 2.5 D), an energy
recovery rate of approximately 1.3% is obtained.

30-39Effects of Volute Throat Enlargement and Fluid
Viscosity on the Performance of an Over Hung
Centrifugal Pump

Davood Khoeini, Alireza Riasi, Ali Shahmoradi

In the current study, identifying regimes and behaviors of the various
viscous fluids in a typical horizontal singlestage centrifugal pump andimproving its performance by enhancing volute throat area have beensurveyed numerically and experimentally. Indeed the initial pump had
insufficient head at BEP (Best Efficient Point) in relevant applications. In
order to solve this problem, the method of increasing the volute throat
area on the prototype was used in steps and eventually the increased
head values have been achieved. Then modified centrifugal pump, thathas been constructed based on the modified control volume fromCentrifugal pump, Numerical and Experimental Study,
numerical results, has been tested thoroughly. The maximum head andPerformance curve, Volute Throat Area, Increased
efficiency discrepancy between numerical and experimental results in
Head, Viscosity Effects
BEP were 1.4 and 2.6% respectively. The effects of viscous fluids, from 1
cSt to 500 cSt, on the performance curves of centrifugal pump havebeen investigated as well and results showed that viscous fluids has
significant effect on them. Indeed the highest head and efficiency in thesame conditions at BEP has been obtained in viscosity 1 cst which wasby 19.2% and 44% greater than the viscosity 500 cSt. It is also foundthat the highest viscous fluid had the highest energy consumption as
the absorbed power of highest viscous fluid, 500 cSt, increased up to
approximately 55% above the lowest viscous fluid, 1 cSt, values.
Small valves including ball valves, gate valves and butterfly valves have been adopted in thefields of steam power generation, petrochemical industry, carriers, and oil tankers. Butterfly
valves have normally been applied to fields where in narrow places installing the existing
valves such as gate valves and ball valves have proven difficult due to the surrounding area
and the heavier of these valves. Butterfly valves are used to control the mass flow of thepiping system under low pressure by rotating the circular disk installed inside. The butterfly
valve is benefitted by having simpler structure in which the flow is controlled by rotating thedisc circular plate along the center axis, whereas the weight of the valve is light compared to
the gate valve and ball valve above-mentioned, as there is no additional bracket supporting
the valve body. The manufacturing company needs to acquire the performance and life test
equipment, in the case of adopting the improving factors to detect leakage and damage on

40-46
Vol. 10,
No. 1,
JanuaryMarch,
2017

Development of Life Test Equipment with Real Time
Monitoring System for Butterfly Valves

the seat of the valve disc. However, small companies, which are manufacturing the industrial

Gi-Chun Lee, Byung-Oh Choi, Young-Bum Lee, Jongvalves, normally sell their products without the life test, which is the reliability test and
Won Park, Tae-Yeon Nam, Keun-Won Songenvironment test, because of financial and manpower problems. Furthermore, the failure mode

Butterfly valve, Life test, Real time monitoring system,
Rated pressure, Leakage, Valve seat, Discanalysis of the products failed in the field is likewise problematic as there is no systemcollecting the failure data on sites for analyzing the failures of valves. The analyzing andresearching process is not arranged systematically because of the financial problem. Therefore
this study firstly tried to obtain information about the failure data from the sites, analyzed thefailure mode based on the field data collected from the customers, and then obtained fielddata using measuring equipment. Secondly, we designed and manufactured the performanceand life test equipment which also have the real time monitoring system with the naked eye
for the butterfly valves. The concept of this equipment can also be adopted by other valves,
such as the ball valve, gate valve, and various others. It can be applied to variously sized
valves, ranging from 25 mm to large sized valves exceeding 3000 mm. Finally, this study carries
out the life test with square wave pressure, using performance and life test equipment. The

47-53

54-62

63-75

76-85

86-98

Thrust Characteristics and Nozzle Role of Water Jet
Propulsion

Performance Analysis of a Combined Blade Savonius
Wind Turbines

A Design Method for Cascades Consisting of Circular
Arc Blades with Constant Thickness

Effect of deflected inflow on flows in a stronglycurved 90 degree elbow

Numerical Simulation on the Performance of Axial
Vane Type Gas-Liquid Separator with Different Guide
Vane Structure

Yongyan Ni, Weimin Liu, Zhanhao Shen, Xiwei Pan

Surface pressure integration and momentum method were respectively
performed to evaluate the impeller thrust and the system thrust of a contrarotating axial flow water jet propulsion, and an interesting phenomenon socalled thrust paradox was revealed. To explain the paradox, the impeller thrust
and the system thrust were physically and theoretically analyzed, the results
show that the impeller thrust is head involved and is determined by thehydraulic parameters upstream and downstream the impeller, while themomentum method depicted by a classic equation is valid simply under the
Water jet propulsion, Thrust paradox, Pump system,
best efficiency point. Consequently, the role of a water jet propulsion nozzle
Nozzlewas deduced that the nozzle is mainly to limit the flow rate that crosses theimpeller and to assure the system working under the best efficiency condition
apart from its ability to produce momentum difference. Related mathematicalformula expressed the nozzle diameter is the dominant variable used to
calculate the working condition of the water jet propulsion. Therefore thenozzle diameter can be steadily estimated by the former expression. The
system thrust scaling characteristics under various speeds were displayed lastly.

Arifin Sanusi, Sudjito Soeparman, Slamet Wahyudi,
Lilis Yuliati

The Savonius wind turbine has a lower performance than other types of windturbines which may attract more study focus on this turbine. This study aimed
to improve wind turbine performance by combining a conventional blade with
an elliptical blade into a combined blade rotor. The analysis was performed on
three blade models in computational fluid dynamics (CFD) using ANSYS_Fluent
Release 14.5. Then the results were verified experimentally using an open wind Savonius turbine, combined blade, performance, CFD,
tunnel system. The results of the numerical simulation were similar to theexperimental
experimental and showed that the combined blade rotor has better dragging
flow and overlap flow than the conventional and elliptical blade. Experimental
verification showed that the combined blade was to increase the maximum
coefficient of power (Cpmax.) by 11% of the conventional blade and to 5.5%of the elliptical blade.

Tao Bian, Qianpeng Han, Martin Böhle

Many axial fans have circular arc blades with constant thickness. It is still achallenging task to calculate their performance, i.e. to predict how large theirpressure rise and pressure losses are. For this task a need for cascade data
exists. Therefore, the designer needs a method which works quickly for design
purposes. In the present contribution a design method for such cascades
consisting of circular arc blades with constant thickness is described. It isbased on a singularity method which is combined with a CFD-data-based flow Cascade, Circular Arc Blades, CFD-data-based, loss
loss model. The flow loss model uses CFD-data to predict the total pressure
model
losses. An interpolation method for the CFD-data are applied and described indetail. Data of measurements are used to validate the CFD-data andparameter variations are conducted. The parameter variations include thevariation of the camber angle, pitch chord ratio and the Reynolds number.
Additionally, flow patterns of two dimensional cascades consisting of circular
arc blades with constant thickness are shown.

Wall pressure measurements and flow visualization were conducted for a 90
degree elbow with an axis curvature radius the same as its inner diameter (125mm). Reynolds numbers 320,000 and 500,000, based on the inner diameterand bulk velocity, were examined. A deflected inflow, having an almost
constant velocity slope and a faster velocity at the inside, was introduced.
90 degree elbow, deflected inflow, pressure
Yukiharu Iwamoto, Ryo Kusuzaki, Motosuke Sogo, Ensemble averaged pressure distributions showed that no difference ofmeasurements, power spectral density functions, flow
Kazunori Yasuda, Hidemasa Yamano, Masaaki Tanaka normalized pressure could be found in both the Reynolds number cases.
visualization
Power spectral density functions of pressures exhibited that the fluctuation
having the Strouhal number (based on the inner diameter and bulk velocity)of 0.6 existed in the downstream region of the elbow, which was 0.1 larger
than that of the uniform inflow case [1]. Results of numerical calculations
qualitatively coincided with the experimental ones.

Yang Fan, Liu Ailan, Guo Xueyan

In order to obtain high efficiency and low resistance droplet separation
apparatus, axial vane type gas-liquid separators with different guide vanes
were designed, and the RNG k-ε model as well as discrete phase model (DPM)
were used to investigate the flow pattern inside the separators. It was shownthat the tangential velocity distribution under different guide vanes haveaxial vane type gas-liquid separator, numerical
Rankine vortex characteristics, pressure distribution exhibits a high similarity
simulation, guide vane, separation efficiency
which value becomes big as the increase of the blade outlet angle and thedecrease of the guide vane numbers. The increase of the guide vane numbers
and the decrease of the blade outlet angle could make separation improvesignificantly. The separation efficiency is almost 100% when the droplet
diameter is bigger than 40μm.

Page

Title

Author

Abstract

Keywords

ECHO progress was defined to depict the rotordynamic pump theory
development. Experience (E) era for pumps lasted nearly one and a half
hundred years before the Industrial Revolution due to the low rotation speedof motor and undeveloped manufacture ability. Classic (C) theory referring to

99-118

An Outlook on Rotordynamic Pump Theory
Development

Yongyan Ni, Zhongyong Pan

quasi-static performance as well as the items those were not able to be
steadily resolved under the level were briefly and sophisticated outlined. Since
rotordynamic pump, ECHO progress, quasi-static, flow
1962, flow instabilities and the dynamic responses had come into main
instabilities, multiphase flow
attention with the development of the modern technologies such as ballistic
missile, rocket and space shuttle main engine, and were finally heuristically (H)elucidated by talented scholars and researchers. Recently, new applications forthe pumps open (O) to the surrounding fluid and diversity of the medium
such as multiphase flow need more studies and some examples were briefly
introduced to display the potential problems lastly.
Although the stall stagnation phenomena have often been experienced in site and also
analytically in numerical experiments in surges in systems of compressors and flow
paths, the fundamental causes have not been identified yet. In order to clarify thesituations, behaviours of infinitesimal disturbance waves superposed on a main flow
were studied in a simplified one-dimensional flow model. A ratio of the amplifying rateof the system instability to the characteristic slope of the compressor element was
surveyed as the instability enhancement factor. Numerical calculations have shown thefollowing tendency of the factor. In the situation where both the sectional area ratio
and the length ratio of the delivery flow-path to the suction duct are sufficiently large,

119-137

A Study on the Fundamental Cause of Stall
Stagnation Phenomena in Surges in Compressor
Systems

Nobuyuki Yamaguchi

the enhancement factors are greater in magnitude, which means occurrence ofordinary deep surges. However, in the situation where the area ratio and/or the length
ratio is relatively smaller, the enhancement factor tends to lessen significantly, whichsituation tends to suppress deep surges for the same value of the characteristic slope.
It could result in the stall stagnation condition. In the domain of area ratio vs. length
ratio of the delivery duct to the suction duct, contour-lines of the enhancement factor

Compressor system, Surge, Stall, Stall stagnation,
System instability, Acoustic waves

behave qualitatively similar to those of the stall stagnation boundaries of a fan
analytically obtained, suggesting that a certain range of the enhancement factor values
could specify the stagnation occurrence. The significant decreases in the factors areobserved to accompany appearances of phase lags and travelling waves in the wave
motions, which macroscopically suggests breaking down of the complete surge actionsof filling and emptying of the air in the delivery duct. The strength of the action is
deeply related with acoustic interferences and is evaluated in terms of the volumemodified reduced resonance frequency proposed by the author. These observations

138-145

The Effect of Different Inflows on the Unsteady
Hydrodynamic Characteristics of a Mixed Flow Pump

Long Yun, Wang Dezhong, Yin Junlian, Cai Youlin,
Feng Chao

waterjet pump and, the channel head of steam generator which is directly
connect with reactor coolant pump. Generally, pumps are identical designs
and are selected based on performance under uniform inflow with the straight
pipe, but actually non-uniform suction flow is induced by upstream
equipment. In this paper, CFD approach was employed to analyze unsteadyhydrodynamic characteristics of reactor coolant pumps with different inflows.
The Reynolds-averaged Naiver-Stokes equations with the k-ε turbulencemodel were solved by the computational fluid dynamics software CFX toconduct the steady and unsteady numerical simulation. The numerical resultsof the straight pipe and channel head were validated with experimental data
for the heads at different flow coefficients. In the nominal flow rate, the head hydrodynamic, radial force, mixed flow pump, channelof the pump with the channel head decreases by 1.19% when compared tohead, non-uniform
the straight pipe. The complicated structure of channel head induces the inlet
flow non-uniform. The non-uniformity of the inflow induces the difference ofvorticity distribution at the outlet of the pump. The variation law of blade toblade velocity at different flow rate and the difference of blade to blade
velocity with different inflow are researched. The effects of non-uniform inflow
on radial forces are absolutely different from the uniform inflow. For the radial
forces at the frequency fR, the corresponding amplitude of channel head are
higher than the straight pipe at 1.0Фd and 1.2Φd flow rates, and thecorresponding amplitude of channel head are lower than the straight pipe at
0.8Φd flow rates.

Anant Kr. Rai, Arun Kumar

Sediment flow through hydropower components causes hydro-abrasiveerosion resulting in loss of efficiency, interruptions in power production anddowntime for repair/maintenance. Online instruments are required tomeasure/capture the variations in sediment parameters along with collecting
samples manually to analyse in laboratory for verification. In this paper, various
sediment parameters viz. size, concentration (TSS), shape and mineralcomposition relevant to hydro-abrasive erosion were measured and discussedwith respect to a hydropower plant in Himalayan region, India. A multifrequency acoustic instrument was installed at a desilting chamber tocontinuously monitor particle size distribution (PSD) and TSS entering theturbine during 27 May to 6 August 2015. The sediment parameters viz. TSS,
size distribution, mineral composition and shape entering the turbine were
Hydro-abrasive, erosion, sediment, turbidity, LISST,
also measured and analysed, using manual samples collected twice daily fromhydropowerhydropower plant, in laboratory with instruments based on laser diffraction,
dynamic digital image processing, gravimetric method, conductivity, scanningelectron microscope, X-ray diffraction and turbidity. The acoustic instrument
was able to capture the variation in TSS; however, significant deviations were
found between measured mean sediment sizes compared to values found in
the laboratory. A good relation was found for turbidity (R2 = 0.86) and laser
diffraction (R2 = 0.93) with TSS, which indicated that turbidimeter and laser
diffraction instrument can be used for continuous monitoring of TSS at theplant. Total sediment load passed through penstock during study period wasestimated to be 15,500 ton. This study shall be useful for researchers andhydropower managers in measuring/monitoring sediment for hydro-abrasiveerosion study in hydropower plants.

Deyou Li, Hongjie Wang, Torbjørn K. Nielsen, Ruzhi
Gong, Xianzhu Wei, Daqing Qin

Performance characteristics in pump mode of pump-turbines are vital for thesafe and effective operation of pumped storage power plants. However, thehead characteristics are different under different guide vane openings. In thispaper, 3-D steady simulations were performed under 13mm, 19mm and 25mm
guide vane openings. Three groups of operating points under the three GVOs
were chosen based on experimental validation to investigate the influence ofguide vane setting on flow patterns upstream and downstream. The results
Pump-turbine, Guide vane setting, Performance
reveal that, the guide vane setting will obviously change the flow patterncharacteristic, Euler theory, Hydraulic loss, Vortices
downstream, which in turn influences the flow upstream. It shows a strong
effect on hydraulic loss (power dissipation) in the guide and stay vanes. It isalso found that the hydraulic loss mainly comes from the flow separation andvortices. In addition, in some operating conditions, the change of guide vane
opening will change the flow angle at the runner inlet and outlet, which willchange the Euler momentum (power input). The joint action of Euler
momentum and hydraulic loss results in the change of the head characteristics.

Vol. 10,
No. 2,
April-June,2017

146-153154-163

Sediment monitoring for hydro-abrasive erosion: A
field study from Himalayas, India

Influence of Guide Vane Setting in Pump Mode on
Performance Characteristics of a Pump-Turbine

Francis turbines are often operated over a wide load range due to highflexibility in electricity demand and penetration of other renewable energies.
This has raised significant concerns about the existing designing criteria.
Hydraulic turbines are not designed to withstand large dynamic pressureloadings on the stationary and rotating parts during such conditions. Previous
investigations on transient operating conditions of turbine were mainly
focused on the pressure fluctuations due to the rotor-stator interaction. This
study characterizes the synchronous and asynchronous pressure and velocity

164-175

Characteristics of Synchronous and Asynchronousmodes of fluctuations in Francis turbine draft tube
during load variation

Rahul Goyal, Michel J. Cervantes, Bhupendra K.
Gandhifluctuations due to rotor-stator interaction and rotating vortex rope during
Francis turbine, transient, particle image velocimetry,load variation, i.e. best efficiency point to part load and vice versa. The
pressure measurements, load rejection, load
measurements were performed on the Francis-99 test case. The repeatability ofacceptance, rotating vortex rope formation,
the measurements was estimated by providing similar movement to guide
synchronous and asynchronous modes
vanes twenty times for both load rejection and load acceptance operations.
Synchronized two dimensional particle image velocimetry and pressure
measurements were performed to investigate the dominant frequencies offluctuations, vortex rope formation, and modes (rotating and plunging) of therotating vortex rope. The time of appearance and disappearance of rotating
and plunging modes of vortex rope was investigated simultaneously in thepressure and velocity data. The asynchronous mode was observed todominate over the synchronous mode in both velocity and pressure
measurements.
The nozzle-flapper valves are widely applied as a pilot stage in aerospace and militarysystem. A subject of the analysis presented in this work is to find out a reasonable
range of null clearance between the nozzle and flapper. This paper has presented a
numerical flow coefficient simulation. In every design point, a parameterized model iscreated for flow coefficient simulation and cavitation under different conditions with

176-187

Numerical Simulation and Experimental Research of
the Flow Coefficient of the Nozzle-Flapper Valve
Considering Cavitation

Lei Li, Changchun Li, Hengxuan Zhang

varying gap width and inlet pressure. Moreover, a new test device has been designed
to measure the flow coefficient and for visualized cavitation. The numerical simulationand test results both indicate that cavitation intensity gets fierce initially and shrinks

Nozzle-flapper valve, Flow coefficient, Servo valve,
Cavitation, Numerical simulation

finally as the gap width varies from small to large. From the curve, the flow coefficient
mostly has experienced three stages: linear throttle section, transition section andsaturation section. The appropriate deflection of flapper is recommended to make thegap width drop into the linear throttle section. The flapper-nozzle null clearance is
optionally recommended near the range of DN/16. Finally through simulation it is also
concluded that the inlet pressure plays a little role in the influence on the flowPage

188-196

Title

Physical and Numerical Investigation of Cavitating
Flow-Induced Vibration of a Flexible Hydrofoil

197-208 Cavitation Compliance in 1D Part-load Vortex Models

209-217

218-226

Novel methods of increasing the storage volume at
Pumped Storage Power plants

Numerical Investigation on Hydrodynamic
Characteristics of a Centrifugal Pump with a Double
Volute at Off-Design Conditions

Author

Abstract

Keywords

Qin Wu, Guoyu Wang, Biao Huang

The objective of this paper is to investigate the flow-induced vibration of aflexible hydrofoil in cavitating flows via combined experimental and numericalstudies. The experiments are presented for the modified NACA66 hydrofoil
made of POM Polyacetate in the closed-loop cavitation tunnel and thenumerical investigations are performed using a hybrid coupled fluid structure Cloud cavitation, Cavitating flow-induced vibration,interaction model. The results showed that with the decreasing of cavitation
Flexible hydrofoil, Cavitation-excited pressure
number, the vibration magnitude increases dramatically for the cloudfluctuation, One-dimensional model
cavitation and declines for the supercavitation. The cloud cavitation
development strongly affects the vibration response, with the main frequencyof the vibration being accordance with the cavity shedding frequency andother two frequencies corresponding to the bending and twisting frequencies.

Peter K Dörfler

When Francis turbines operate at partial load, residual swirl in the draft tube
causes low-frequency pulsation of pressure and power output. Scale effects
and system response may bias the prediction of prototype behavior based onlaboratory tests, but could be overcome by means of a 1D analytical model.
This paper deals with the two most important features of such a model, theFrancis turbine, model test, draft tube vortex, scalecompliance and the source of excitation. In a distributed-parameter version,
effect, cavitation, similarity
compliance should be represented as an exponential function of local
pressure. Lack of similarity due to different Froude number can thus becompensated. The normally unknown gas content in the vortex cavity has
significant influence on the pulsation, and should therefore be measured andconsidered as a test parameter.

Pål-Tore Storli

The paper presents two novel concepts of increasing the energy storage
capacity at pumped storage power plants, both existing and new projects. The
concepts utilize compressed air as a working medium to displace water from a
volume originally not available for storage. The concepts are likely to give
additional storage volume at a low cost, however, much development andPumped Storage Power plants, Energy storage, Novel
many investigations are needed before the concepts can be shown to beconcepts, Renewable Energy
technical and economical feasible solutions for energy storage. The concepts
are disclosed so that researchers and utilities can start those investigations,hopefully helping the green transition by providing highly valuable energy
storage for a future renewable energy having a much higher share of
renewable energies than the current systems.

Hyeon-Seok Shim, Kwang-Yong Kim

Severe radial thrust under off-design operating conditions can be aharmful factor for centrifugal pumps. In the present work, effects ofgeometry of a double volute casing on the hydrodynamic performanceof a centrifugal pump have been investigated focusing on off-design
conditions. Three-dimensional steady Reynolds-averaged Navier-Stokes
analysis was carried out by using shear stress transport turbulencemodel. Numerical results for the hydrodynamic performance of thecentrifugal pump were validated compared with experimental data. The
hydraulic efficiency and radial thrust coefficient were used as
performance parameters to evaluate the hydrodynamic characteristics of Centrifugal pump, Double volute casing, Radial thrust,the centrifugal pump. The cross-sectional area ratio of the volute casing, Hydraulic efficiency, L18 orthogonal array
the expansion coefficient of the rib structure, the distance between the
rib starting point and volute entrance, and radius and width of thevolute entrance, and length of the rib structure, were selected asgeometric parameters. Results of the parametric study show that theperformance parameters are significantly affected by the geometricvariables and operating conditions. Optimal configurations of the
double volute casing based on the design of experiments techniqueshow outstanding performance in terms of the efficiency and radial
thrust coefficient.
The accuracy of turbulence models for the Reynolds-Averaged Navier-Stokes (RANS) equations
in rough-wall flows is evaluated using data from large-eddy simulations (LES) of boundary

227-239

Evaluation of turbulence models in rough wallboundary layers for hydroelectric applications

Rabijit Dutta, Jonathan Nicolle, Anne-Marie Giroux,
Ugo Piomellilayers with favourable and adverse pressure gradients. Some features of the flow (such as flow
reversal in the roughness sublayer) cannot be captured accurately by any model, due to thefundamental model formulation. In mild pressure gradients most RANS models are sufficiently
accurate for engineering applications, but if strong favourable or adverse pressure gradientsare applied (especially those leading to separation) the model performance rapidly degrades.

Vol. 10,
No. 3,
JulySeptember, 2017turbulence modelling, large-eddy simulations,roughness, boundary layers, separation

Latin hypercube sampling is widely used design-of-experiment technique toselect design points for simulation which are then used to construct asurrogate model. The exploration/exploitation properties of surrogate models
depend on the size and distribution of design points in the chosen design
space. The present study aimed at evaluating the performance characteristics
of various surrogate models depending on the Latin hypercube sampling (LHS)
procedure (sample size and spatial distribution) for a diverse set of
optimization problems. The analysis was carried out for two types of problems:240-253

Effects of Latin hypercube sampling on surrogate
modeling and optimization

Arshad Afzal, Kwang-Yong Kim, Jae-won Seo(1) thermal-fluid design problems (optimizations of convergent-divergent
micromixer coupled with pulsatile flow and boot-shaped ribs), and (2)analytical test functions (six-hump camel back, Branin-Hoo, Hartman 3, andHartman 6 functions). The three surrogate models, namely, response surface
approximation, Kriging, and radial basis neural networks were tested. The

Latin hypercube sampling, Optimization, Surrogate
model, Cross-validation, Global Optimization

important findings are illustrated using Box-plots. The surrogate models wereanalyzed in terms of global exploration (accuracy over the domain space) andlocal exploitation (ease of finding the global optimum point). Radial basis
neural networks showed the best overall performance in global exploration
characteristics as well as tendency to find the approximate optimal solution forthe majority of tested problems. To build a surrogate model, it isrecommended to use an initial sample size equal to 15 times the number ofdesign variables. The study will provide useful guidelines on the effect of initialsample size and distribution on surrogate construction and subsequent
optimization using LHS sampling plan.

Vol. 10,
No. 3,
JulySeptember, 2017254-263264-273287-295

Numerical Cavitation Intensity on a Hydrofoil for 3D
Homogeneous Unsteady Viscous Flows

Annual Energy Production Maximization for Tidal
Power Plants with Evolutionary Algorithms

Pressure Pulsation Characteristics of a Model Pumpturbine Operating in the S-shaped Region: CFD
Simulations

296-306 How to Avoid Severe Incidents at Hydropower Plants

The cavitation erosion remains an industrial issue for many applications. This
paper deals with the cavitation intensity, which can be described as the fluid
mechanical loading leading to cavitation damage. The estimation of thisquantity is a challenging problem both in terms of modeling the cavitating
flow and predicting the erosion due to cavitation. For this purpose, anumerical methodology was proposed to estimate cavitation intensity from 3D
unsteady cavitating flow simulations. CFD calculations were carried out using
Code_Saturne, which enables U-RANS equations resolution for a
Christophe Leclercq, Antoine Archer, Regiane Forteshomogeneous fluid mixture using the Merkle's model, coupled to a k-ε
cavitation, cavitation intensity prediction, erosion
Patella, Fabien Cerru
turbulence model with the Reboud's correction. A post-process cavitation
intensity prediction model was developed based on pressure and void fraction
derivatives. This model is applied on a flow around a hydrofoil using different
physical (inlet velocities) and numerical (meshes and time steps) parameters.
The article presents the cavitation intensity model as well as the comparison ofthis model with experimental results. The numerical predictions of cavitation
damage are in good agreement with experimental results obtained by pitting
test.

Evgenia Kontoleontos, Simon Weissenberger

In order to be able to predict the maximum Annual Energy Production (AEP)
for tidal power plants, an AEP optimization tool based on Evolutionary
Algorithms was developed by ANDRITZ HYDRO. This tool can simulate all
operating modes of the units (bi-directional turbine, pump and sluicing mode)and provide the optimal plant operation that maximizes the AEP to the control
Annual Energy Production, tidal power plants,
system. For the Swansea Bay Tidal Power Plant, the AEP optimization
optimization, Evolutionary Algorithms, Swansea Bay
evaluated all different hydraulic and operating concepts and defined the
optimal concept that led to a significant AEP increase. A comparison between
the optimal plant operation provided by the AEP optimization and the fullload operating strategy is presented in the paper, highlighting the advantageof the method in providing the maximum AEP

Linsheng Xia, Yongguang Cheng, Fang Cai

The most detrimental pressure pulsations in high-head pump-turbines iscaused by the rotor-stator interaction (RSI) between the guide vanes andrunner blades. When the pump-turbine operates in the S-shaped region of thecharacteristic curves, the deteriorative flow structures may significantly
strengthen RSI, causing larger pressure pulsations and stronger vibration withan increased risk of mechanical failure. CFD simulations were carried out toanalyze the impacts of flow evolution on the pressure pulsations in the Sshaped region of a model pump-turbine. The results show that the reverse
flow vortex structures (RFVS) at the runner inlet have regular development andtransition patterns when discharge reduces from the best efficiency point
Rotor-stator interaction, Pressure pulsations, rotating(BEP). The RFVS first occur at the hub side, and then shift to the midspan nearstall, Pump-turbine, S-shaped characteristics
the no-load point, which cause the strongest pressure pulsations. The locally
distributed RFVS at hub side enhance the local RSI and makes the pressure
fluctuations at the corresponding sections stronger than those at the rest
sections along the spanwise direction. Under the condition of RFVS at the
mid-span, the smaller flow rate make the smaller difference of pressure
pulsation amplitudes in the spanwise direction. Moreover, the rotating stall,rotating at 35.7%-62.5% of the runner rotational frequency, make the low
frequency components of pressure pulsations distribute unevenly along thecircumference in the vaneless space. However, it have little influence on the
distributions of high components.

Masashi Yasuda, Satoshi Watanabe

Hydropower is now changing its role from the energy generator into the mostpowerful and reliable tool for stabilizing the electrical network, especially
under the increase of intermittent power sources like wind-power and solarpower. Although the hydropower plants are the most robust generating
facilities, they are not immune from unexpected severe incidents having long
downtime, considerable restoration cost and sometimes fatalities. The present hydropower plant, severe incident, flood, fire, turbine
paper provides some study results about severe incidents in the conventional failure, generator failurehydropower plants, mainly about the flood, fire and electromechanicaltroubles, except for the incidents of civil facilities. It also provides somepossible scenarios which may lead some measures how to avoid such
incidents. Finally, it provides some comprehensible recommendations to avoid
severe incidents based on experiences.
In liquid-propellant rockets, POGO instability can occur, in which a fluctuationof propellant supply to the engine, a thrust fluctuation, and a structural
vibration are coupled. For the prediction of this instability, it is required toprovide dynamic characteristics of the pump represented as the transfer matrix
correlating the upstream and downstream pressure and flow rate fluctuations.
Inducer, Cavitation, Dynamic transfer matrix, Dynamic
In the present study, the flow rate fluctuation is evaluated from the fluctuation
characteristics, Experiment, CFD
of pressure difference at the different locations assuming that the fluctuation iscaused by the inertia of the flow rate fluctuation. The experiments were
performed in some flow conditions, and it was shown that the tendencies ofdynamic characteristics are related to excitation frequencies, cavitation
numbers and flow rate coefficients.

307-317

Measurement of Dynamic Characteristics of an
Inducer in Cavitating Conditions

Takuya Ashida, Keita Yamamoto, Koichi Yonezawa,
Hironori Horiguchi, Yutaka Kawata, Yoshinobu
Tsujimoto

Page

Title

AuthorStudy on Influence of Blade Number on Aerodynamic
318-327 Noise of Half-ducted Propeller Fans for Packaged Airconditioners

Taku Iwase, Tetsushi Kishitani, Masato Furukawa

Abstract

Keywords

Flow fields in 2-blade and 4-blade half-ducted propeller fans for the outdoor
units of air-conditioners were calculated with large eddy simulation based on
finite element method with the aim of investigating the influence of blade
number on aerodynamic noise. We confirmed that the tip vortex had a great
influence on aerodynamic noise in half-ducted propeller fans. The length ofHalf-ducted propeller fan, Tip vortex, Aerodynamic
the tip vortex trajectory and the blade pitch for the 2-blade propeller fan were noise, Large eddy simulation
longer than those for the 4-blade propeller fan. These were suppressed theinteraction between the tip vortex and the adjacent blade in the 2-blade
propeller fan. The 2-blade propeller fan was therefore more silent than the 4blade propeller fan.

The servo valve is the key component in the electrical-hydraulic servo system.
Status for the servo valve temperature drift characteristics of the test system isstudied in this paper firstly. Since Research on temperature servo valve drift

328-335

Research on Temperature Current Drift Characteristics
Test of Force Feedback Hydraulic Servo Valve

Lei Li, Hao Yan, Changchun Li

characteristics has not formed systematic theory. As for Position closed-loop
fluid power transmission and control, servo valve,
test method, the theory and calculation algorithms of servo valve temperaturetemperature drift characteristics, electrohydraulicdrift are analyzed. Simulation and experiments both show the feasibility of thecontrol equipment
theory test, and by a large number of experiments, the servo valve drift results
are put into classification. Finally, corresponding phenomenon is elaborated,pointing out its causes and appropriate preventive measures, hoping to reducedrift value influenced by the temperature on the servo valve.

336-344

Feasibility Analysis of Existing Compressor Design for
Different Refrigerants

Arihant Sonawat, Young-Seok Choi, Kyoung-Yong
Lee, Hyeon-Mo Yang, Jin-Hyuk Kim

The destruction of ozone layer due to the use of refrigerants is a matter ofconcern in the present world. This has been addressed through various
platforms and several guidelines have been framed for their usage to prevent
its further degradation. Since the existing chlorofluorocarbon (CFC) andhydrofluorocarbon (HCFC) refrigerants are at the verge of phasing out because Computational fluid dynamics, turbo chiller,of their higher environmental impacts, this has raised various questions about refrigerant, global warming, centrifugal compressor
the systems which employ these refrigerants. One such question is: Will theexisting systems work efficiently when the existing refrigerant is replaced by a
viable environment friendly substitute? The present work makes an effort toanswer this question.

CFD has played a significant role to investigate the performance and improvethe design of hydraulic turbines; however, the improvement of CFD methoddemands powerful computer resources including time, CPU, memory, andcommercial licenses. In present work, both global and local parameters of ahigh head Francis turbine were studied using several geometrical and interface
modelling approaches. The aim of the work is to find suitable strategy for
Ruzhi Gong, Chirag Trivedi, Ole G. Dahlhaug, Torbjøn
Hydraulic turbine, modeling strategy, pressure345-354 Blade passage modeling strategy for hydraulic turbine
designers to simulate the hydraulic turbines to balance the numerical accuracy
K. Nielsen
fluctuation, rotor-stator interaction
and the requirement of computational resources. The geometrical modelling
approaches include combinations of turbine components such as, spiral casing,
distributor, runner and draft tube. The interface modelling approaches
includes, stage, Frozen rotor and transient rotorstator types. The study showedthat the proper combinations of both approaches can effectively reduce thenumerical error.

355-362363-377

Investigation of Pressure Pulsations and Flow
Instabilities in a Centrifugal Pump at Part-loadConditions

A Study on the Deep-Surge Frequencies in Various
Conditions of Axial Flow Compressors and Flow-paths

Denghao Wu, Yun Ren, Jiegang Mou, Yunqing Gu

Nobuyuki Yamaguchi

The flow instabilities and pressure pulsations can be generated during thepump's operation. However, it is even more serious under the part-loadcondition. Currently, the links between flow instabilities and pressure pulsations
were still not fully understood. In the present study, the experimental
investigation was performed on pressure pulsations by utilizing the dynamic
pressure transducers and the internal unsteady flow structures were measured
by PIV. The pressure pulsations were extracted at 6 different locations around centrifugal pump, pressure pulsations, flow
the volute under different flow rates conditions ranging from 10% to 120% of instabilities, vortices
the nominal flow rate. The study allowed relating the pressure pulsations andunsteady flow structures in a pump. It was noted that higher intensive
broadband pressure pulsations can be found at the small flow rate together
with the fully developed flow instabilities. This led to the preliminary
conclusion that the broadband pressure pulsations are exclusively induced by
the flow instabilities, especially the vortices in the flow passages of impeller.
Frequencies of deep surges and their behaviors in axial flow compressors weresurveyed numerically. Relative surge frequencies, normalized by the basic
acoustical resonance frequencies, are seen to tend to lower together withincreases in the stalling pressure ratios, i.e. increases in the number of stages
and the compressor tip speed, and also together with increases in the flowpath sectional area ratios. However, it appears difficult to express simply thegeneral behaviors of the relative frequencies affected by the various factors. In
Fluid Machine, Axial Flow Compressor, Surge,
order to know the essential behaviors, a modified reduced surge frequency is
Analytical Simulation, Frequency, Fluid Dynamics
proposed, which is a dimensionless number comparing the mass flow fillingand emptying the plenum volume in surge and the mass flow provided by thecompressor. The modified reduced surge frequencies are found to have or
approach a definite and nearly constant value in conditions of deep surges.
The parameter suggests the fundamental mechanism of deep surges andcould be used to determine approximate frequencies of deep-surges invarious conditions of compressors and flow-paths.
In consideration of the particle features and behaviors, the Computational Fluid Dynamics(CFD)-Discrete Element Method (DEM) coupled method has been applied to simulate theliquid-solid flows in the centrifugal pump with crystallization phenomenon. The crystal particles
tend to distribute more uniformly in the inlet section and enter the impeller along the378-384

CFD-DEM Simulation for Distribution and Motion
Feature of Crystal Particles in Centrifugal Pump

Dong Liu, Cheng Tang, Shicheng Ding, Binhao Fu

pressure sides of the blades with a moderate rise in velocity. Particle number density isdifferent at different regions in the impeller passages with the characteristics of small density

Centrifugal pump, crystallization phenomenon, CFDDEM, particle feature and behavior

near suction sides and large density near pressure sides. In addition, large crystal particles aremainly located near the pressure sides and small crystal particles predominantly appear in theregion near suction sides. The relative velocity magnitude of flow near the impeller inlet tends
to be higher than that of crystal particles, while the velocities of the solid particles are

385-393

Internal Flow and Performance with Foreign
Vegetable Materials in a Contra-Rotating Small
Hydro-Turbine

Comparative Performance Analysis of an Electric394-403 Motor Cooling Fan with Various Inlet Vent and Blade
ShapesVol. 10,
No. 4,
OctoberDecember,
2017

Ding Nan, Toru Shigemitsu, Shengdun Zhao,
Yasutoshi Takeshima

Jae-Min Park, Kwang-Yong Kim, Man-Woong Heo

Small hydropower generation is one of important alternative energy, andpotential of small hydropower is great. Efficiency of small hydro-turbine islower than that of large one, and these small hydro-turbine's common
problems are out of operation by foreign materials. Therefore, we adopted
contra-rotating rotors, which can be expected to achieve high performanceand enable to use low-solidity rotors to achieve stable operation. Experimental
apparatus of the contra-rotating small hydro-turbine with 60mm casing
Small hydro-turbine, Contra-rotating rotors, Internal
diameter was manufactured and some experiments were conducted. In thisflow, Performance, Flow visualization
research, the internal flow with foreign vegetable materials, i.e. leaves andgrasses, were investigated by a high speed camera, and the performanceexperiments when two pieces of cudweeds were attached on the blade offront rotor were conducted. As the results shown, the passing rate of small
leaves is 41.2% and all of the middle leaves can't pass through the contrarotating small hydro-turbine. The highest efficiency also decreased about 13%,reaching to 51.2% at 1.4Qd, because of the foreign vegetable materials.
Electric motors are used as the main power sources in many industrial
equipments and household appliances. The miniaturization and weight
reduction of electric motors generally increase the internal heat generation.
Therefore, it is important to understand the flow characteristics of motor
cooling fans and to improve their performance. The present study aimed at
systematically investigating the effects of the inlet vent and blade shapes on
the aerodynamic performance of a low-voltage electric motor cooling fan. The
flow characteristics of the low-voltage electric motor cooling fan was
numerically analyzed using three-dimensional Reynolds-averaged NavierStokes equations. The k-ε turbulence model was selected for the analysis ofMotor cooling fan, Reynolds-averaged Navier-Stokes
turbulence using a turbulence model test. An optimal grid system in theequations, Inlet vent, Bi-directional blade, Mass flow
computational domain was selected through a grid dependency test. The masscoefficient, Torque coefficient
flow coefficient and torque coefficient were considered as the performanceparameters of the cooling fan. Eleven inlet vent shapes and eleven blade
shapes of the cooling fan were tested by evaluating the aerodynamic
performance of the cooling fan. The mass flow coefficient and torquecoefficient were considered as the performance parameters of the motor
cooling fan. Eleven inlet vent shapes on the fan cover and eleven blade shapes
were tested to evaluate their effects on the mass flow coefficient and torquecoefficient. The maximum mass flow coefficient of 0.0908 and the minimum
torque coefficient of 0.0089, were achieved using different combinations ofvent and blade shapes.

To analyze the dynamic evolutions between the draft tube pressure pulsationsand vortex ropes of a Francis turbine, the runaway transient process of ahydropower system is simulated by coupling a one-dimensional model of the404-411

Dynamic evolutions between the draft tube pressure
pulsations and vortex ropes of a Francis turbine
during runaway

Xiaoxi Zhang, Qiuhua Chen, Jie Liaowater conveyance system and a three-dimensional model of the Francis
turbine. The results show that the annular-distributed pressure pattern at theentrance of the draft tube breaks and induces small vortex ropes, which thenmerge into an eccentric-distributed helical one with the transient operating
point moving away from the rating region. In this process, low frequency

Francis turbine, runaway, 1D-3D coupling, numericalsimulation, pressure pulsations, flow patterns

pressure pulsations form and continue to strengthen. When the operating
point moves to the runaway point, the vortex ropes keep dividing andmerging irregularly, causing random-like pressure pulsations.
In order to investigate the effect of solid particles on the cavitation
characteristics and lubricating properties of the micro-gap liquid film in

Effect of Solid Particles on Cavitation and Lubrication
412-420 Characteristics of Upstream Pumping Mechanical Seal
Liquid Membrane

421-431432-438

Unstructured Grid Smoothing for Turbomachinery
Applications

Unsteady Flow Condition of Centrifugal Pump for
Low Viscous Fluid Food

Huilong Chen, Dongdong Sun, Yuanzheng Wu,
Miaomiao Chen, Peilin Zhang

Upstream pumping mechanical seals,the Eulerian multiphase flow model wasused to simulate the liquid film with different diameter and volume fraction ofsolid particles to analyze the influence of the particles on the distribution of
vacuole , opening force and friction torque of the film under different working
conditions. The results showed that the particles have an inhibitory effect on
the cavitation, and the cavitation area and the volume fraction of the bubbles
were both decreased.The cavitation area increased with the increase of particle
diameter, which indicated that the inhibition of cavitation was weakened with
the increase of particle diameter. The cavitation area decreased with theUpstream pumping mechanical seal, Particles,
increase of the particle volume fraction, and the volume fraction increased the Cavitation, Lubrication, Opening force, Friction torquecavitation inhibition effect. The presence of particles improved the opening
force of liquid film to a certain extent and increased with the increase ofparticle volume fraction , but the effect of particle diameter on opening force
was different under different rotating speed and different medium
pressure.The friction torque did not change obviously with the particle
diameter,and decreased only slightly with the increase of the particle volume
fraction.In the working condition range, the cavitation degree is not related tothe pressure of the medium, but increases with the increase of the rotational
speed, and the cavitation area and volume fraction of bubbles Weresignificantly decreased when there were solid particles.

In the present study, two mesh smoothing techniques, Laplace and Winslow
smoothing techniques, for unstructured grids on turbomachinery application
are investigated. These operators are based on the solution of elliptic
equations. In the first case, Laplace`s equations are solved using a barycentric
Mehdi Falsafioon, Sina Arabi, Ricardo Camarero, Franç averaging procedure. Solution of Winslow`s equations has been a challenging Grid Smoothing, Unstructured Grid, Winslow`sois Guibault
work for unstructured grids because of existence of cross derivative terms in Equation, Grid quality
the equations. This issue is addressed devising a local control volume. Bothmethods are compared using different grid quality criteria. Finally, these
operators have been applied to turbomachinery configurations and theadvantages and disadvantages are discussed.

Toru Shigemitsu, Junichiro Fukutomi, Takumi
Matsubara, Masahiro Sakaguchi

Fluid machineries for fluid food have been used in wide variety of field i.e.
transportation, filling, and improvement of quality of fluid food. The flow
condition of these fluid machineries is quite complicated because the fluid
food is different from water. Therefore, a design method based on the internal
flow condition is not conducted. In this research, a turbo-pump having small
number of blades was used to decrease shear loss and keep wide flow
Centrifugal pump, Numerical analysis, Unsteady flow,
passage. In previous studies, it was found that internal flow condition was
Low viscous fluid
complex in the test pump, but those flow phenomena were not clarified indetail. In order to investigate the complex internal flow condition, theunsteady numerical analysis using low viscous fluid was conducted. In thispaper, the relation between the blade geometry and the performance wasinvestigated. In addition to that, the internal flow condition of the centrifugal
pump using low viscous fluid was clarified by the numerical analysis results.

439-446447-456

Effects of Surface Roughness on Thermal andHydrodynamic Behaviors in Microchannel Using
Lattice Boltzmann Method

Design and Performance Analysis of Axial Hydro
Turbine with Criteria of Tangential Velocity andConstant Diffusion Factor

M. A. Taher, M. K. Dey, Y. W. Lee

The aim of the present study is to use the artificial roughness geometries inorder to investigate the thermal and hydrodynamic behaviors in a roughmicrochannel using the most effective alternative method in micro-flows
namely Lattice-Boltzmann Method (LBM). The rough surfaces are configured
with triangular, trapezoidal and rectangular roughness elements with a relativeroughness height 0~8% of the channel height. To analyze the roughness
Lattice-Boltzmann, Friction factor, Nusselt number,effects, the friction coefficients in terms of Poiseuille number (Pn), the rate of Surface roughness, Microchannel
heat transfer in terms of Nusselt number (Nu) and the mass flow rate havebeen discussed at the slip flow regime, 0.01 ≤ Kn ≤ 0.10, where Kn is theKnudsen number. Finally, the overall performance has been studied
numerically. All of these numerical results for all kind of roughness geometries
are compared with smooth microchannel.

Priyono Sutikno, Nono Suprayetno, Nathanael P.
Tandian, Firman Hartono

In reality, the flow condition inside meridional channel may vary from hub totip, therefore meridional analysis will affect to the blade geometry whether istwisted or tapered. The prediction of maximum surface velocity is not easy, but
Lieblein was postulated the alternative form of diffusion factor (DF) on airfoil
which can be applied for the cascade analysis. Diffusion factor on cascade is
an important design parameter to avoid cavitation in turbomachinery due tothe pressure distribution and velocity variation on the surface. The purpose ofpresent study is to know the influence of tangential velocity distribution andtangential velocity, cascade, diffusion factor,
constant DF on the blade shape and performance of the axial hydro turbine.
meridional analysis, pitch chord ratio, axial hydroThere are four criteria of tangential velocity distribution or usually is called asturbineswirl velocity that discussed in this paper, they are mixed vortex, free vortex,
forced vortex and constant vortex. Constant DF was applied to the alltangential velocity distribution to obtain pitch chord ratio calculation. This willaffect to the pitch chord ratio value and the blade shape of rotor. Performance
prediction of axial turbine is performed through Computational Fluid Dynamic(CFD) to validate global parameter design. The result of numerical simulation
can be used as basic consideration for manufacturing and experimental
testing.
Numerical simulations of vortex-induced vibration of a three-dimensional
flexible Cylinder under uniform turbulent flow are calculated when Reynolds
number is 1.35×104. In order to achieve the vortex-induced vibration, thethree-dimensional unsteady, viscous, incompressible Navier-Stokes equationand LES turbulence model are solved with the finite volume approach, theCylinder is discretized according to the finite element theory, and its dynamic
equilibrium equations are solved by the Newmark method. The fluid-Cylinderinteraction is realized by utilizing the diffusion-based smooth dynamic meshmethod. Considering VIV system, the variety trends of lift coefficient, dragcoefficient, displacement, vertex shedding frequency, phase difference angle of
Cylinder are analyzed under different frequency ratios. The nonlinear
Vortex-induced,dimensional, finite element, lift
phenomena of locked-in, phase-switch are captured successfully. Meanwhile, coefficient
the limit cycle and bifurcation of lift coefficient and displacement are analyzed
using trajectory, phase portrait and Poincare sections. The results reveal that:when drag coefficient reaches its minimum value, the transverse amplitude
reaches its maximum and the "lock-in" begins simultaneously. In the range of"lock-in", amplitude decreases gradually with increasing of frequency ratio.
When lift coefficient reaches its minimum value, the phase difference, between
lift coefficient and lateral displacement, undergoes a suddenly change fromthe "out-of-phase" to the "in-phase" mode. There is no bifurcation of lift
coefficient and lateral displacement occurred in three dimensional flexible
Cylinder submitted to uniform turbulent flow.

457-464

Numerical Simulation of Vortex Induced Vibration of
A Flexible Cylinder

Mojtaba Hosseini, Hamid reza Ashrafi, Peyman
Beiranvand, Ahmad Dehestani, Kiuomars Dehestani

Page

Title

Author

Abstract

Keywords

Flow of steam is different from other gas flows and involves droplet
generation in the flow field. This phase-transition affects not only flow aspects,
but also machine performance in a negative way. These days, CFD is widelyused in machine design and optimization processes, so phase-transition

1-12

Effects of Relative Position between a Stator and a
Rotor on Steam Condensing Flow in Rotating
Machinery

Changhyun Kim, JaeHyeon Park, Jehyun Ba다

phenomena in steam flows should be considered in CFD to predict the internal
flows precisely. In the past, non-equilibrium wet-steam model was
implemented on in house code T-Flow and it was applied to steadyNon-equilibrium wet-steam model, Rotating
calculations of a steam turbine model with changing stator/rotor interface. The machinery, Steam condensing flow
results showed that mixing plane method is not appropriate to simulate steam
condensing flow and frozen rotor method can be affected by relative position
between a stator and a rotor. Therefore, steady wet-steam flows with nonequilibrium phase-transition were simulated for a steam turbine model in thisstudy with 4 different stator-rotor positions and their effects on the wet-steam
flow fields were investigated in detail.

13-20

21-29

30-38

On-line Measuring Method of Effective Bulk Modulus
in Hydraulic System Based on Frequency Analysis

Numerical Analysis of Contra-Rotating Small HydroTurbine with Cylinder Spoke

Simulation Analysis of Cylinder Impact Performance
Influenced by Shaft Sleeve Structure

Yingshu Chen, Nan Wang, Lichen Gu

Ding Nan, Toru Shigemitsu, Shengdun Zhao,
Yasutoshi Takeshima

Cong Liu, Pei Xiao, Xingli Li, Gangyan Li

Based on the gas-liquid phase flow theory, an indirect method is proposed toon-line measure the effective bulk modulus by constructing the mathematicalmodel which reveals the relationships of the effective bulk modulus, bubble
volume fraction, pressure and natural frequency. The natural frequency of
hydraulic fluid is a key parameter for measuring effective bulk modulus
Effective bulk modulus, Pseudo-excitation, Condition
utilizing the model, so it is online measured by the proposed pseudomonitoring, Frequency domains, Bubble volume
excitation method. The frequency response function is obtained by solving thefraction
amplitude spectrum functions of pseudo-excitation signal and the response
signal, and the natural frequency is obtained. The numerical simulation andexperiment are carried out, and we can deduce from the analysis of simulationand experimental results that the effective bulk modulus in hydraulic system
can be easily online measured by the proposed indirect method.
Small hydropower is one of potential energy resource existing in our living
environment and yet not been widely used. Small hydro-turbine is suitable inthese energy resources while it still has some shortages, like performing low
efficiency and easy to be out of control when there are foreign materials in
the water. Thus we designed this contra-rotating small hydro-turbine toincrease its efficiency and enhance its ability of keeping stable operation. The
experimental apparatus was designed and assembled, and some experiments
were conducted. A new kind of cylinder spoke, which supports the front andrear rotor, was adopted and the numerical analysis was carried out in thispaper. As the numerical analysis results shown, the efficiency of test turbinewith cylinder spoke increased in a wide range of flow rate. The maximum
efficiency increased about 2.2%, reaching to 66.4%, and it was obtained at
1.25Qd. The internal flow condition, especially at the areas behind the spoke,
was improved by the cylinder spoke.

Small hydro-turbine, Contra-rotating rotors, Cylinder
spoke, Performance, Internal flow condition

To study the cylinder motion characteristics, cylinder and shaft sleevestress characteristics of cylinder stroke and return process influenced bydifferent shaft sleeve structure, the cylinders with non-chamfering shaft
sleeve, C0.3 chamfering shaft sleeve and R0.3 round corner shaft sleeve
were used for simulation of cylinder stroke and return process. The
results show that the piston velocity curves of three kinds of shaft
sleeve are identical. Maximum stress of different shaft sleeves fluctuatesand maximum stress elements of C0.3 and R0.3 shaft sleeve are similar. Cylinder, Shaft sleeve structure, Dynamic simulation
When cylinder strokes, maximum stress of cylinder occurs at the end ofpiston rod connected to the load; the stress of C0.3 shaft sleeve is thelowest. When cylinder returns, maximum stress of cylinder occurs at theshaft sleeve; the stress of C0.3 and R0.3 shaft sleeve differ little and areboth lower than that of non-chamfering shaft sleeve. It provides areference for structure optimization and service life improvement of thecylinder shaft sleeve.
To improve the design of the splitter blade in the centrifugal pump impeller, inner flow
numerical simulations are performed on the centrifugal pump impeller without splitter blades
firstly, inner flow diagnoses are performed based on the theory of the boundary vorticity
dynamics, and distributions of the boundary vorticity flux (BVF), friction force as well asvorticity on the inner walls of the impeller are carefully analyzed to find the location of bad
flows and their dynamic sources. Later, according to the inner flow diagnosis results, splitterblades are designed and reformed for the original impeller. The inner flow filed in the

39-45

Design Improvement of the Splitter Blade in theCentrifugal Pump Impeller Based on Theory ofBoundary Vorticity Dynamics

Binjuan ZHAO, Chenghu ZHANG, Youfei ZHAO,
Yanxia FU, Qi LIU, Huilong CHEN

impellers equipped with the preliminary splitter blade and reformed splitter blade are
numerically simulated and diagnosed. Finally, comparisons are made among the three
impellers, and it is found that, compared to the original impeller (impeller 0), the BVF, friction

Centrifugal pump impeller, Splitter blade, Boundary
vorticity dynamics, Inner flow diagnosis, Design
improvement

force and vorticity distribution in the impeller equipped with the preliminary splitter blade(impeller 1) has no obvious improvement, although the pump head increases, the efficiency
decreases; the BVF, friction force and vorticity distribution in the impeller equipped with thereformed blade (impeller 2) has improved obviously, BVF peak decreases evidently and BVF
distributes more uniformly, flow separation is inhibited, the hydraulic force acting on the
impeller increases, with the pump head and efficiency increasing dramatically. It is proven that,flow diagnosis based on the theory of the boundary vorticity dynamics is an effective

An improvement of the half-ducted axial flow fan design by applying the

46-54

Vol. 11,
No. 1,
JanuaryMarch,
2018

55-62

63-76

Effect of Vortex Design on a Half-Ducted Axial Flow
Fan (In the case of forced vortex design)

Wave Energy Harvesting Turbine: Effect of Hub-ToTip Profile Modification

Review of Fluid Structure Interaction Methods
Application to Floating Wave Energy Converter

forced vortex design to the rotor blade was conducted by CFD. The quasi
three-dimensional flow theory was applied for the half-ducted fan design, andthe meridional flow was calculated by the method of streamline curvature.
When the radial balance equations from hub to tip was solved, the vortex
Atsushi Kaji, Yoichi Kinoue, Norimasa Shiomi, Toshiaki design was changed from the constant-whirl-velocity design to the forced
Axial flow fan, Half-ducted fan, Internal flow,
Setoguchi
vortex design in reference to our previous experimental results of the halfStreamline inclination, Numerical analysis
ducted fan's internal flow. The analysis of the three-dimensional internal flow
fields of the half-ducted fan designed by adopting the forced vortex design
was conducted. As a result of CFD, the efficiency η of the fan was about 1-3 %larger at the flow rate coefficient φ of 0.158-0.343 than the constant-whirlvelocity design.
The present paper investigates the leading edge (LE) undulations of a Wells
turbine blade through numerical analysis. The aspiration for this modification
came from humpback whales, which have uneven protrusions at the LE of theirpectoral flippers. The flippers help whales to maneuver during swimming. The
work is performed by using three-dimensional steady, incompressible Reynolds
P. Madhan Kumar, Paresh Halder, Abdus Samad, Shin
Averaged Navier-Stokes (RANS) equations with turbulent closer model. The LE Wells turbine, Undulated blade, OWC, Wave energy
Hyung Rheeof the turbine blades is modified with undulations of three different
amplitudes: 1mm, 2.5mm, and 4mm. The results show that the undulation
changes the turbine performance. The amplitude 2.5mm gives the peak
performance. The comparison between blades with different amplitudes andthe reference blade has been discussed throughout this study.

Mohammed Asid Zullah, Young-Ho Lee

Computational fluid dynamics (CFD) is a highly efficient paradigm that is used
extensively in marine renewable energy research studies and commercial
applications. The CFD paradigm is ideal for simulating the complex dynamics
of Fluid-Structure Interactions (FSI) and can capture all kinds of nonlinear fluid
motions. While nonlinear simulations are considered more expensive andresource intensive compared to the frequency domain approaches, they aremuch more accurate and ideal for commercial applications. This review study
presents a comprehensive overview of the computation fluid dynamics
CFD, FSI, Navier-Stokes equation, WEC, nonlinear,paradigm in context of wave energy converter (WEC) and highlights different simulations
CFD tools that are available today for commercial and research applications.
State-of-the-art CFD codes such as ANSYS CFX that are highly ideal for WEC
simulation problems are highlighted and aspects such as time and frequency
domains are also thoroughly discussed along with efficacy of the nonlinear
simulations compared to the linear models. The paper presents a comparativeevaluation of different WEC modelling codes available today and illustrates thecode framework of different CFD simulation software suites.

Rotating stall phenomenon limits the operation range of turbomachines,
therefore it is important to understand the crucial parameters of thisphenomenon. In the present study, the diffuser rotating stall in a three-stage

77-84

Experimental Analysis of Diffuser Rotating Stallin aThree-Stage Centrifugal Pump

centrifugal pump was experimentally studied. Examined main parameter was
an axial offset of rotor against the stationary part, which might be unavoidable
due to accumulation of geometrical tolerances and assembling errors. The
Multi-stage centrifugal pump, Vaned diffuser,
Taiki Takamine, Daichi Furukawa, Satoshi Watanabe,
effect of leakage flow rate at the balance drum section employed as a thrust Rotating stall, Rotor axial offset, Static pressure
Hiroyoshi Watanabe, Kazuyoshi Miyagawa
balancing device, which increases the thru-flow rate at the first and second
fluctuation
stage diffusers, was also studied. The effect of rotor axial offset was clearlyobserved and, with the rotor axial offset to the suction side, the rotating stall
appeared only at the third stage diffuser. By setting the balance flow rate set
to zero, the onset range of rotating stall became wider in the first and second
stage diffusers, which was well explained by the decrease of the thru-flow rate.

85-96

97-109110-114

Numerical Investigation of the Turbulent Cavitating
Flow over Submerged Bodies

Comparison of Loss Models for Performance
Prediction of Radial Inflow Turbine

Effect of Impulse Turbine Geometry on the
Performance of a Dual-Turbine System for Wave
Energy Conversion

Hong Feng, Gao Zhenjun, Liu Lili, Yuan Jianping

A numerical method for the calculation of turbulent cavitating flow oversubmerged objects is proposed in present work. Cavitation is modeled via asingle-fluid cavitation model which is derived based on a truncated form of
the Rayleigh-Plesset equation and the mixture multiphase theory. The
approach has been implemented by user-define function which is widely usedin ANSYS FLUENT. Detailed results are presented for sheet cavitation over a
submerged hemispherical object in a wide range of cavitation numbers andthe cloud cavitation around a Clark-Y hydrofoil. In particular, for thehemispherical body, we compared the surface pressure distribution with
Submerged bodies, multiphase approach, cavitating
experimental data which was available in literature. Later the cloud cavitation flow, turbulence, numerical simulation
structure and its effect on the forces of the hydrofoil were studied. The
comparisons between the simulating and experimental results show that
present numerical approach has good capability to predict the surfacepressure coefficient and the pulsation frequency at cavitation number σ=0.4,
0.55 and 0.65 of the hemispherical body under cavitation conditions.
Meanwhile, for the hydrofoil, the proposed approach is sufficiently robust to
predict the characteristics of the time-averaged lift and drag coefficients andthe evolution of the cloud cavity with time.

Seong Kuk Cho, Jekyoung Lee, Jeong Ik Lee

This paper is aimed for suggesting the best combination of loss models for aradial inflow turbine among various empirical models from the open
literatures. The 1D mean streamline analysis procedure is utilized to confirm
the suitability of loss models and the recommended combinations. The
performance of loss models are evaluated by comparing to the welldocumented NASA turbine test data. To suggest a more acceptablecombination of loss models, each loss model is analyzed and assessed in
Radial inflow turbine, Preliminary design, Performanceaccordance with the proven loss mechanisms. This study especially focused on estimation, Loss models, 1D mean stream line analysis
the rotor passage loss and the tip clearance loss, and the tip clearance loss
model modification was suggested. The agreement of the newly suggested
loss model combination with test data is significantly improved in comparison
to the existing combinations. The design procedure presented in this paper
can be used as a 1D design tool of a radial inflow turbine for the preliminary
design phase.

Manabu Takao, Haruka Katsube, M. M. A. Alam,
Seisuke Fukuma, Shinya Okuhara, Yoichi Kinoue

115-122

Effect of Different Guide Vane Numbers on Transient
Radial Force of Pump as Turbine

FengXia Shi, JunHu Yang, XiaoHui Wang

Page

Title

Author123-128

129-138

Design of Mixed-flow pump for Ns475 Based on
Optimum Design Database

Numerical Simulation and Experimental Research
about Shock Wave in 1+1/2 Counter-Rotating
TurbineSung Kim, Kyoung-Yong Lee, Jin-Hyuk Kim, JoonYong Yoon, Young-Seok Choi

Chao Li, Huoxing Liu

Wells turbine, widely used to harness the wave energy, has high efficiency at a
low flow rate. However, it has severe stall problem. In order to alleviate thisproblem, a dual-turbine system of Wells turbine with a booster impulse
turbine was proposed. In the present study, the effect of impulse turbine
Fluid Machinery, Impulse Turbine, Wave Energy
geometries on the performance of combined turbine system was investigatedConversion, Wells Turbine
by CFD analysis. As a result, the boosting effect of impulse turbine depends on
the pressure differences that caused by the setting angles at a high flow rate.
Moreover, the decrease of flow rate with the setting angle has a significant
influence on the efficiency.
Guide vane was added to pump as turbine (PAT), the transient flow
characteristics of PAT were calculated and experimented under different guidevane numbers. The results show that after the PAT was added guide vane, thedistribution of speed streamline and blade load is more uniform than before,
Pump as turbine, Guide vane numbers, Radial force,and the unsteady radial force on impeller decreased greatly, which is good for
Blade load
the stability of PAT's operation. When the guide vane number is equal to 9,
both the maximum radial force difference and dominant frequency amplitudeof radial force are the minimum. So there is an optimal guide vane number,
for the given geometric parameters of PAT.
Abstract

Keywords

In this study, a mixed-flow pump with a specified specific speed was optimallydesigned by utilizing computational fluid dynamics (CFD). Additionally, theshape of the mixed-flow pump and flow characteristics depending on thespecific speed were studied, in order to development of hydrodynamic design
system for mixed-flow pump. A mixed-flow pump consists of an impeller anda diffuser and the shapes of mixed-flow pumps show a certain tendency
depending on specific speed. With an analysis of the shapes of a mixed-flow
pump, the optimal shape to satisfy design specifications can easily be
Hydrodynamic design system, Mixed-flow Pump,
designed. The design variables of the impeller and diffuser were defined in
Impeller, Diffuser, Design optimization
meridional plane and vane plane development, and optimum design of theimpeller and diffuser was carried out by using design of experiment (DOE). The
tendencies of design variables depending on specific speed were analyzed byutilizing the shape of optimally designed mixed-flow pump. The mixed-flow
pump shape of required design specification was designed by using thetendencies of design variables depending on specific speed. The performanceof designed model has been verified using CFD.
To investigate the internal distribution regularities of shock wave structure in
1+1/2 (without low pressure guide vane) counter-rotating turbine, both steadyand unsteady numerical simulation about a designed 1+1/2 counter-rotating
turbine are conducted, and experimental research about the shock wave
structure of high pressure guide vane, high pressure rotor and low pressure
rotor was also conducted by using the schlieren apparatus under different
working conditions. The numerical simulation divides into two parts: steadyand unsteady calculation. The result of steady simulation under designed
condition shows that there appears supersonic flow and shock wave at the exitof root in high pressure guide vane, while supersonic flow appears at theentire passage of the blade outlet in both the high pressure rotor and low
pressure rotor, together with strong shock wave and complex wave structures. Numerical Simulation, Experimental Research, Shock
From the point of the unsteady results, the unsteady effect has few influence Wave Structure, 1+1/2 Counter-Rotating Turbine,on the flow field of high pressure guide vane, but the wake of the highSchlieren display technology
pressure guide leaves periodically sweeps through the front edge of the highpressure blade and there presents strong unsteady effect on flow field of highpressure rotor. Then, to deeply research the characteristics of the shock wave
structure, 50% height section of the blade of the three types of blades are
extracted respectively to make plane cascades which are conducted blowing
experiments in supersonic wind tunnel. During the experiment schlieren display
technology is used to record the shock wave structure changing process inthree cascade flow passage under the design Angle of attack when pressure
ratio changes from 1.7 to 2.5. The final photograph were analyzed bycomparing with the CFD results. Results show that with the increase of
expansion ratio, the wave structures in both high and low pressure bladeTo improve centrifugal pump cavitation performance, the slot pulse jet pumpis proposed. The slot is designed directly on the impeller shroud near thesuction side of the blade leading edge. The slots are alternately blocked by thecambered prominence, which is designed at the impeller front side chamber
along the circumferential direction. The leakage flow from the front sidechamber flows into the slot alternately, and the pulse jet is formed near theblade inlet. Because of the strong shear, the pulse jet is more efficient thansteady jet in terms of energy transmission. Based on the numerical simulation,

139-145

Investigation on the effect of slot pulse jet on
centrifugal pump performance

Renhui Zhang, Lichen Yun

the hydraulic performances of the slot pulse jet pumps with two different
pulse frequencies are compared with the slot steady jet pump. The calculation
centrifugal pump, slot impeller, slot pulse jet pump,
result shows that with the increase of flow rate, the head and efficiency of thepulse jet, cavitation performance, pulse frequency
three kinds of pumps are basically the same. The cavitation performance ofslot pulse jet pump is better than that of slot steady jet pump, especially forslot pulse jet pump II. The distribution of pressure difference acted on the slot
appears to be jagged, and the pulse frequency is consistent with shaft
frequency or its harmonic frequency. The amplitude of the pressure fluctuation
on slot jet pump II is much higher than that of the slot pulse jet pump I. The
vapor volume distribution in the middle span of the impeller for slot pulse jetpump is less than that of slot steady jet pump. So, the pulse jet is an effective
way to further improve the cavitation performance of slot steady jet pump,and NPSHr is significantly decreased, especially at design condition.

146-153

Hydrodynamic Damping of a Fluttering Hydrofoil in
High-speed Flows

A hydrofoil resembling a high head Francis runner blade was submerged in arectangular channel and attached to the walls in a fixed-beam configuration.
The hydrofoil was excited by piezoelectric Macrofiber composite actuators(MFCs), and the vibration was measured at the trailing edge with Laser
Doppler Vibrometry (LDV) and semiconductor strain gauges. The hydrofoil wasCarl W. Bergan, Bjørn W. Solemslie, Petter Østby, Ole exposed to water velocities ranging from 0 to 25 m/s. Lock-in occurred at
FSI, Damping, Francis, FRF
G. Dahlhaug
approx. 11 m/s. The damping increased linearly with the water velocity, with aslope of 0.02 %/(m/s) below lock-in, and 0.13 %/(m/s) above lock-in. The
natural frequency of the foil increased slightly with increasing water velocity
below lock-in, due to the added stiffness of the passing water. Additionally,
the natural frequency increased significantly when passing through lock-in,
due to the vortex shedding phase shiftVol. 11,
No. 2,
April-June,2018154-162

163-170

Research on Steady Characteristics of F-π Bridge
lectro-hydraulic Proportional Pressure Reducing Valve

Inverse Design of Airfoil Using Vortex Element
MethodLi Yu, Hu Yanping, Mo Hu

This paper establishes the idea of a pressure reducing valve with an F-π bridge
hydraulic resistance network as its pilot circuit under the theory of π bridge
hydraulic resistance networks. It analyzes the working principle of the valve
and establishes the nonlinear equations of flow pressure through the hydraulicresistances and force balance between the pilot and main valves. It derives theanalytical expression for steady flow pressure of the F-π bridge electroF-π bridge, proportional pressure reducing valve,
hydraulic proportional pressure reducing valve and then determines that the nonlinear equations, override pressure, simulation,
override pressure of the F-π bridge electro-hydraulic proportional pressure
hydraulic resistances
reducing valve is 0.0037% of the traditional type. A simulation shows that theflow pressure of the F-π bridge electro-hydraulic proportional pressure
reducing valve is related to the hydraulic resistances of the pilot circuit and ismore stable than the traditional electro-hydraulic proportional pressure
reducing valve.

Avinash G.S., S. Anil Lal

A methodology for the parameterization and inverse design of airfoils, forobtaining a given target surface pressure distribution is presented. The airfoil
parameterization is carried out using ordered pairs representing the x-y
coordinates of ten control points of Bezier curve as parameters. The forward
model consists of analysis of flow over airfoils carried out using vortex element
Bezier parameterization, Inverse design, Airfoil, Vortex
method, which involve discretisation of the airfoil curve alone, in contrast toelement method, Genetic algorithm
complicated grid generation over the region of flow. The airfoil parameters are
selected by global search using a Genetic Algorithm code. Examples toillustrate the parameterization and design of airfoils are presented. A good
matching between the target and designed airfoil shows that present
methodology can be used as a tool for the design of airfoils.
A prefabricated pumping station catering to the delivery of medium with high flow rate isinvestigated. Two configurations of storage tanks are devised. Computational fluid dynamics(CFD) is utilized to acquire flow patterns in the pumping station as the pumps operate

171-180

Flow Features of a Prefabricated Pumping Station
Operating under High Flow Rate Conditions

Flow Features of a Prefabricated Pumping Station
Operating under High Flow Rate Conditions

concurrently. Flow rate allocation and the disturbance of pump operation to ambient medium
are depicted. It is demonstrated that both the serial and parallel configurations can fulfill therequirements of high flow rate. Flow rate differs over storage tanks and pumps as well, as isprefabricated pumping station, CFD, multiple storage
tanks, flow rate allocation, flow structure

intensified with the serial configuration. The operation of the pumps arouses non-symmetricflow structures in the tank. In comparison, the parallel configuration is desirable inconsideration of the uniformity of cross-sectional total pressure and velocity distributions in

181-190191-204

Prediction of the Noise Reduction by Shroud Shapeand the Characteristics of Flow-induced Noise
Generated in an Axial Flow Fan

Enhancement of a Centrifugal Pump Performance by
Simultaneous Use of Splitter Blades and Angular
Impeller Diffuser

Tae-Gyun Lim, Wan-Ho Jeon, Gaku Minorikawa

In this study, computational fluid dynamics (CFD) and computational
aeroacoustics (CAA) were used to reduce the noise of a small axial cooling fanthat is widely applied to electronic devices. The noise of an axial cooling fanthat was measured in semi-anechoic room was compared with the results
obtained from CAA. Three-dimensional Navier-Stokes equations were solved
for the unsteady flow field simulation. The noise was calculated by using
simplified Ffowcs Williams and Hawkings (FW-H) equation. The result of CAA Computational fluid dynamics, Computational
was consistent with one data obtained from the experiment. The results ofaerocoustics, Axial flow fan, Noise reduction
unsteady flow field presented the noise generation mechanism and that of
CAA presented the sound sources. The shape of a shroud was a factor causing
one of the major noise sources on the fan surface. The shape modification wasmade in the inlet of the shroud for noise reduction. The Overall Sound
Pressure Level (OASPL) was reduced by 3.7 dB compared to that predicted forBase model.

Davood Khoeini, Ebrahim Shirani

The influences of different configurations of impeller diffusers and splitterblades on performance of a centrifugal pump have been analyzed
experimentally and numerically. Each impeller with different configurations
including three different splitter blades with lengths of 0, 0.45L and 0.75L (L isthe length of impeller blades) and three different cases of impeller withdiffuser of α=0o α is the divergence angle of diffuser walls) and angular
diffuser of α=10o and impeller without diffuser have been investigated in thisstudy. Data analyses revealed that there is good compatibility among
Centrifugal pump, performance enhancement,
experimental and numerical results and the highest head discrepancy is only 7
impeller diffuser, splitter blade
percent. Results showed that simultaneous use of impeller diffuser and splitterblade have profound impact on the centrifugal pump performance. Actually,among all configurations, the maximum performance is achieved for the
impeller equipped with angular diffuser of α=10o and splitter blades of 0.75L
concurrently. In that case, the head at high flow rate is 1.51 times of the headvalue of original impeller without impeller diffuser. In addition, at BEP (Best
Efficiency Point), efficiency increased by 3.4 percent and its position displaced
towards the high flow rate as well.

This paper presents the influence of different inlet conditions on theperformance of micromixer. On the purpose of obtaining the internal flow
fields and mixing characteristics, there are 28 micromixers with different
structural parameters have been studied by numerical simulations. The
influence of different inlet conditions on the mixing performance of
micromixers with periodic triangle baffles and rectangle baffles was examinedby experiments. The results of experiment and numerical simulation were
Wei Xu, Xiuhua He, Lingfeng Gao, Tian Xia, Zhengying completely discussed and analyzed. The consistency between results ofMicromixer, Chaotic convection, Lab-On-a-Chip,
205-212 Influence of Different Inlet Conditions on MicromixerYuexperiment and numerical simulation proves the reliability of research method Numerical simulationand the accuracy of numerical simulation. It also indicates that different
numbers of inlets have significant effects on the mixing performance of
micromixers. The optimum inclination angles of inlets for each kind of
micromixer were obtained under different conditions. For optimizing ordesigning passive micromixers, it is an effective way to improve theperformance of micromixers by increasing the number of inlets or changing
the angle of the inlets.
Page

Title

Author

Abstract

Keywords

The effects of the inlet position of blade on the performance of a centrifugal
impeller are numerically investigated. The inlet position of the blade can be
determined by the outer diameter, the leaning angle of the blade inlet, theshroud and hub angular momentums specified at the blade inlet. It is found213-223

Effects of the Inlet Position of Blade on the
Performance of a Centrifugal Impeller

Yunlong Li, Ruizi Zhang, Kaibin Wang, Jingyin Li

that the flow fields of the optimal impeller are obviously superior to those of Blade leading edge position, Three-dimensional
the impeller whose blade leading edge was installed at impeller eye. The range impeller, Blade inlet position, Efficiency, Pressure ratio
analyses reveal that angular momentum specified at the inlet hub is the least
important factor in affecting the efficiency of impeller, while the outer
diameter of blade leading edge plays the most important role in determining
the pressure ratio.
In order to investigate the formation of the rotating stall in diffuser of pumpturbine in pump mode, the unsteady flow with radial rotating characteristics
before the occurrence of rotating stall are investigated by detached eddy
simulation. The results indicate that the unsteady flow patterns which occur in

224-233234-243

Numerical Study on Rotating Characteristics ofUnsteady Flow Inner Pump-turbine in Pump Mode

Aerodynamic Optimization of Squirrel-Cage Fan with
Dual Inlet

244-254

Optimization of a Fluid Distribution Manifold:
Mechanical Design, Numerical Studies, Fabrication,
and Experimental Verification

255-264

Experimental Study of Horizontal Gas-liquid Twophase Flow in Two Medium-diameter Pipes andPrediction of Pressure Drop through BP Neural
NetworksJun Yang, Tian Xie, Pavesi Giorgio, Xiaohua Liu, Jun
Liu

Ruizi Zhang, Kaibin Wang, Yunlong Li, Jingyin Li

Heng Wang, Samuel D. Marshall, Rerngchai
Arayanarakool, Lakshmi Balasubramaniam, Xin Jin,
Poh Seng Lee, Peter C. Y. Chen

the return channel both at full and part load conditions contain two periodical
disturbances with frequencies St≈0.042 and St≈0.085, and the Strouhal
number St is frequency normalized by blade passing frequency of impeller.
pump-turbine, pump mode, unsteady flow, rotating
These periodical disturbances not only influence the pressure field but alsocharacteristics
cause rotating characteristics in diffuser channels. One is composed of 4 cells
propagating at 0.073 times of impeller rotating speed. The other one is madeup of 3 rotating cells with 0.2 times of backward impeller rotating speed.
Meanwhile, there are two radial rotating characteristics which contribute thespectra peak at blade pass frequency in diffuser. One is at the inlet of diffuser
propagating at impeller rotating speed with 7 cells, and the other one contains
4 cells with about 1.75 backward impeller rotating speed.
In this paper, the rotor and the volute of the squirrel-cage fan with dual inlet
were optimized to improve its aerodynamic performance. The blade inlet
angle, blade exit angle and diameter ratio of the impeller were chosen as
optimization variables using the response surface methodology (RSM) to
improve the total pressure. Furthermore, another three optimization variables Squirrel-cage fan, Aerodynamic performance,
were adopted on the basis of previous optimum results, which are the width Response surface methodology, Total pressureof impeller, the location of the impeller annular plate and the location of
cutoff respectively. The simulation and experimental results show that the totalpressure of the optimal model has been greatly improved without noise
increase in comparison with the original model.

This paper presents two optimized designs of a commonly-used fluid
distribution manifold having one entrance and six exits. Numericalsimulations were carried out to optimize the dimensions andmechanisms of these proposed designs for the sake of enhancing theuniformity of fluid distribution amongst the exits and reducing theformation of dead zones inside the manifold cavities. Particularly, tomake the fluid distribution amongst exits more uniform, this study
explored the relationship between entrance diameter and exit diameter.
Furthermore, in order to reduce dead zone formations inside the
manifold whilst still maintaining uniform fluid distribution, a conicalcavity was designed. After that, blockers were designed to replace some
fluid distribution manifold, fluid distribution
exits, permitting a variable number of fluid distribution manifold exits,
uniformity, dead zone reduction, conical cavity,
depending on the specific application. Both designs were found to be
numerical simulation
able to improve flow uniformity and dead zone reduction compared tothe original commonly-used fluid distribution manifold, with the centralfeeding distributor performing slightly better than the lateral-feeding
distributor overall. From the perspective of manufacturing, each of these
two fluid manifolds was made of two pieces with glue and rubber O
ring used respectively as the bond between separate pieces. Preliminary
experiments with these devices suggest similar results to those from thenumerical studies. Based on real application requirements andlimitations, the different fluid manifold designs with tunable dimensions
can be utilized in various mechanical or biochemical devices to
distribute fluid equally amongst several parallel components.

Horizontal gas-liquid two-phase flow is of crucial importance in oil-gas storage andtransportation. In view of previous researches with the lack of horizontal gas-liquid two-phaseflow in medium-diameter pipes (60-75 mm), experiments were conducted in DN 60 and DN75

Wang Qinghua, Zou Honglan, Luo Wei, Yang
Junzheng, Wen Xiaohong, Wang Yan

at medium-high liquid velocity (50-250 m3/d) and high gas-liquid ratio (20-500 m3/m3).
Comparison between flow patterns maps in DN60 and DN75 and the Taitel-Dukler model
showed that only flow patterns map in DN60 agreed well. On the basis of experimental data

horizontal gas-liquid two-phase flow, mediumdiameter pipes, liquid holdup, pressure drop
prediction method, BP neural networks

analysis, variation laws of liquid holdup and pressure drop were determined. Besides, thispaper developed a method to predict liquid holdup and pressure drop through BP neuralnetworks. Results proved the capability of BP neural networks. The further validation can be

265-272 Simulation and Test of Gear Pump Flow Pulsation

273-282

Robust Design Optimization of Hydrodynamic
Characteristics of Airfoil 791

Chen Zongbin, Lv Zhiqiang, Xu Rongwu, Liao Jian

Flow pulsation is the inherent properties of volumetric hydraulic pump, thedirect noise source of hydraulic system. Simulating the internal gear pumps'
flow pulsation based on the mathematical model is difficult, so a new
simulation method was adopted in this article. The chamber of the pump isdivided into four Control Volumes (CVs), whose effective volumes change
along with the rotation of the gears. The CVs take in fluid from suction port
and squeeze fluid out at the outlet port. According the CVs connection
Flow pulsation, gear pump, control volume,
relationship, the pump simulation model was established in AMESim. To verify simulation
the simulation results, flow pulsation experiment was conducted andexperiment data show that simulation model is correct and the accuracy is up
to 95%. Results prove that the modeling method and experiment test are
effective. Thus the evaluation of flow pulsation from simulation to testing wasestablished, which shown great significance to evaluate and develop the
pump's vibration and noise.

Chenghu ZHANG, Binjuan ZHAO, Zhongfu HUANG,
Yanxia FU, Qi LIU, Huilong CHEN

In this paper, the influence of the continuous random variation of the flow
velocity on hydrodynamic characteristics of airfoil 791 was discussed, and arobust design optimization method was proposed to reduce the influence of
uncertain factors on the stability of hydrodynamic performance. Firstly, Bezier
curve was used to parameterize the suction side of the airfoil, and its thickness
was controlled by four points, which was then taken as the optimization
variables. Secondly, the criterion of robustness was given, and then a robust
mathematical model was established. Finally, two objective functions of robust
optimization were gained on the basis of uncertainty analysis with surrogate
model. Combined with multi-objective genetic algorithm, a robust optimal
solution with better hydrodynamic characteristics was obtained. The results
airfoil 791, multi-objective genetic algorithm,
showed that compared with original case, the thickness near trailing edge
robustness, surrogate model, uncertainty analysis
altered more smoothly, the resistance and surface wave intensity were
obviously decreased, and the maximum reduction of drag-lift ratio and wake
unevenness were 6.89% and 25.04% respectively, which contributed to theimprovement of wake quality. The change of surface pressure and resistancecoefficients were also more stable under the variable inlet flow velocity
conditions, and then the robustness was strengthened accordingly. In
conclusion, the robust design optimization can obviously improve thehydrodynamic characteristics of the airfoil while reducing the sensitivity touncertain factors, meanwhile, it can provide better stability during theoperating process.

Vol. 11,
No. 3,
JulySeptember, 2018283-293

Experimental Study of Pulp Suspension Flow in a
Channel with Application to Papermaking

Masaru Sumida, Taro Fujimoto

In this study, the flow characteristics of a pulp suspension in a modeled
headbox channel containing a screen-type circular cylinder were examined
experimentally. The distributions of the pulp fiber concentration and the axial
Pulp-suspension flow, fiber-concentration distribution,
velocity of downstream wake of the cylinder were obtained using thewake, circular cylinder, papermaking machine, opticaltransmitted light attenuation method and particle image velocimetry,measurement
respectively. The influence of flow velocity and the degree of pulp fiber
dispersion were explained. From this information, we explored the feasibility of
improving the efficiency of the hydraulic headbox of a papermaking machine.

This article compares a numerically simulated, and an experimentally obtainedHill-Diagram. The Francis99 model turbine was used in the validation. By using
steady-state simulations and passage modeling in ANSYS CFX, the simulation

294-303

Numerical Generation of Hill-Diagrams; Validation on
the Francis99 Model Turbine

Erik Tengs, Pål-Tore Storli, Martin Aasved Holst

time is in the order of minutes for each operating point. Except for thesmallest guide vane opening, the error in hydraulic efficiency is less than 2.5% Hydro-power, Validation, CFD, Hill-Diagram,for all flow configurations. The individual error in head and torque follow clear, Optimization, Francis99
almost identical trends. The error along a line of small incidence losses indicate
less than 0.5% error in the efficiency in almost the complete simulated range.
The results in this article may be used in future optimization design processes
using Hill-Diagrams.
The reversible pump turbine (RPT) is a suitable machine to control fluctuationsin the energy market. The usage of RPTs for this purpose will increase thenumber of operational mode changes of the machine. In order to reduce the304-311312-320321-332

Fast Transition from Pump to Turbine Mode ofOperation

Dynamic Seal Friction Heat Characteristics Analysis of
Hydraulic Servo Swing Motor

Turntable system, Swing motor, Dynamic seal, Seal
friction, Heat characteristics

Three-dimensional Analysis of Two-way Fluid333-343 structure Interaction on a Flexible Hydrofoil in Viscous
Flow

Magni F. Svarstad, Torbjørn K. Nielsen

response time of the machine, fast transitions between the modes of operation
are necessary. Therefore, increased knowledge of how the machine operates
during these fast transitions is needed. This includes the investigation of thetransient characteristics for the whole operating range of the machine. This
paper presents experimental results from a fast transition from pump toturbine mode. The flow rate is measured by the use of a modified pressure
Reversible pump turbine, Tranient operation, Modetime method. The resulting transient characteristics are compared with steady change
state characteristics. Experiments have been preformed on a model scale
reversible pump turbine in the Waterpower Laboratory at the Norwegian
University of Science and Technology (NTNU). The results show that thepressure pulsations are highest at low discharge in both pump and turbine
mode of operation and at runaway speed in turbine. Oscillations at runaway
speed is reduced with lower opening degree on the guide vanes. The results
also show a difference between the steady state and transient characteristics inthe pump mode due to the inertia of the water masses.

Yannan Zhu, Qiang Zhang, Jianfeng Tao, Dun Tan,
Xuyong Wang

Hydraulic swing motor's dynamic seal friction heat is a direct factor leading tomotor's temperature rise. To study the key factors in motor's dynamic seal
friction heat, therefore, reducing motor's temperature rise, the contact stressmodel and friction model were established. Based on the swing motor of athree-axis turntable system, the relationship between three key factors wasanalyzed. Motor's friction heat characteristics in two conditions were simulated,
Turntable system, Swing motor, Dynamic seal, Sealand simulation results show that with the increase of three factors, the friction
friction, Heat characteristics
heat increases obviously. Further experimental research validated thetheoretical analysis and indicated that friction heat can be significantly
reduced when reducing combined gasket's compression ratio, motor's working
pressure and spindle's speed appropriately. Furthermore, improving themachining precision of motor's seal structure and combined seal's installation
precision also work.

Xuelin Tang, Gao Hui, Wu Zhixing, Hao Man, Shi
Xiaoyan, Li Xiaoqin

Based on Implicit Large Eddy Simulation (ILES), the Adaptive Local
Deconvolution Method (ALDM) was proposed to develop an implicit Sub-Grid
Scale (SGS) model for three-dimensional (3D) turbulent unsteady flow aroundthe NACA0012 Hydrofoil at a high Reynolds number of 2400,000. With thehelp of User Define Function (UDF) of the Fluent CFD software, the 3D
turbulent unsteady flows were carried out by using ILES and LES respectively.
The lift coefficients predicted by both models were in good agreement withthe experimental data and the relative error of lift coefficient predicted byboth models decreases firstly and then increases with the increase of theincident angle, but the numerical results by ILES were more close to theILES, NACA0012, LES, lift coefficient, vortex
experimental, which verified the feasibility and accuracy of the ILES model. In
addition, the predicted pressure contour and streamline distributions by ILES
and LES at different incident angles in a wide range were also investigatedfurther. The larger of the incident angle, the production and shedding of thevortex are stronger. The predicted results by both the models have the similartendency, and the ILES could more finely capture the flow patterns. For a large
incident angle of 20°, the internal flow analyses by ILES could well reproduce
the whole process of the vortex from generation to development andshedding around the hydrofoil

Zahra Mortazavinia, Ricardo Camarero, Francois
Guibault

Two-way Fluid-Structure Interaction of a three dimensional hydrofoil subjected
to viscous flow at Re=750000 is investigated in this paper. A rectangular,cantilevered NACA66 hydrofoil is simulated using a finite element based CSD
code, while the fluid flow is modeled with the incompressible, unsteadyReynolds Averaged Navier-Stokes equations using a finite volume based CFD
Fluid-structure interaction, Two-way, Threecode. The numerical computations are carried out through a strong coupling
dimensional, Hydrofoil, Viscous effects
between these two separate solvers. The strongly coupled FSI solver isvalidated by comparing the present numerical results with experimental
measurements in a water tunnel at the French Naval Academy. To quantify the
FSI effects, rigid (stainless steel) and flexible (POM Poly-acetate) hydrofoils
with the same undeformed geometry are simulated and compared.

Theoretical Estimates of Rotordynamic Fluid Forces on344-356 a Front Shroud of Francis Turbine Caused by Leakage
Flow

Page

357-373

Title

Effects of Pressure Ratios of Axial Flow Compressors
on the Deep Surge Frequencies Part I: Effective
Reduced Surge Frequency and Its Behaviors

Haruka Nishimura, Kazuyasu Sugiyama, Yoshinobu
Tsujimoto, Hajime Koyama

AuthorNobuyuki Yamaguchi

The rotordynamic fluid forces on a columnar rotor modeling the front shroudof Francis turbine caused by the leakage flow and whirling motion areevaluated by the experiments and the computations, to explain the selfexcited vibration observed in free vibration tests. In addition to the leakage
flow models previously proposed, a new model is proposed to include theeffects of the rotation and whirling motion of the rotor to evaluate theRotordynamic Fluid Force, Whirling Motion, Francis
rotordynamic fluid forces. After checking the validity of the models by
Turbine, Columnar Rotor, Leakage Flowcomparisons with experiments and CFD, the characters of each component are
discussed based on the physical mechanism producing the forces. It was foundthat the rotordynamic force component normal to the whirling orbit is mainly
caused by the centrifugal forces of the added mass of the fluid in theclearance and that the tangential force is mainly caused by the acceleration of
the axial leakage flow through the clearance.
Abstract

Keywords

Effects of compressor pressure ratios and flowpath geometries on thefrequencies of deep-surges in multi-stage axial flow compressors are studied
on the basis of numerical experiments. The frequencies tend generally to lower
in a complicated manner toward higher rpms and higher pressure ratios of thecompressors. The general behaviors of the frequencies are found to be
described in large in terms of an effective reduced surge frequency numericalexperimentally searched for. The parameter tends to keep a nearly constantlevel of values for a wide range of stalling pressure ratios, rpms, and number
Fluid Machine, Axial Flow Compressor, Surge,of stages of compressors. For multi-stage compressors, however, at slightly
Frequency, Fluid Dynamics, Analytical Simulation
below the design speed, the parameter values tend to drop rather steeply, andabove the speed, they tend to keep again a new constant level of values atthe lowered level. The transition of the behavior is more significant for theconditions of compressors designed for higher pressure ratios and in shorter
delivery flow-paths. It could be attributed to the effect of a relocation ofsurge-triggering stages in the local zone of the surge flow mode with theamplitude varying much in the axial direction. The detailed phenomena
involved in the behaviors will be clarified in Part 2.

This study investigates the flow characteristics of a spiral-channel viscousmicropump using two-dimensional theoretical analysis. The obtained results
are compared to the results obtained from experiments, numerical simulations,and the theoretical analysis of Kilani et al., and the similarities and differences

374-386

Two-Dimensional Theoretical Study on Flow
Characteristics of a Spiral-Channel Viscous
Micropump

Donghyuk Kang, Koichi Nishibe, Kotaro Sato,
Kazuhiko Yokota

between these approaches are discussed. The present two-dimensional
Micropump, Viscosity, Spiral channel, Pump
theoretical approach is validated. Its accuracy is improved as compared toperformance, Two-dimensional analysis, Reynolds
previous work by setting the spiral-channel axis as the spiral-channel length
numberfrom the pump inlet to the outlet and by considering the moving wall as acomponent in the spiral-channel direction of the circumferential velocity of therotating disk. Furthermore, the present two-dimensional analysis can accurately
predict pump performance, even though the actual flow in the micropump isthree dimensional.

387-399

Vol. 11,
No. 4,
OctoberDecember,
2018
400-411412-423424-431

Performance Characteristics and Flow Field of Axial
Flow Hydraulic Turbine in Shallow Open Channel

Influences of Impeller Splitter Blades on the
Performance of a Centrifugal Pump with Viscous
FluidsProgressive Orthogonal Optimization Design Methodfor High Efficiency Axial-flow Blower

Experimental Investigation under Water Condition on
the Loss of Pipe Material Caused by Solid Particle
Erosion in the Pipe Flow

Yasuyuki Nishi, Genki Sato, Daishi Shiohara, Terumi
Inagaki, Norio Kikuchi

We have been developing an axial flow hydraulic turbine with a collection
device that can be used in open channels with shallow water depths such as
agricultural waterways and small rivers. However, the addition of a collection
device reduces the portability and increases the cost compared to axial flow
hydraulic turbines without a collection device. Therefore, it is important tounderstand the performance characteristics and flow field of the axial flow
hydraulic turbine in open channels while considering the possibility of using
only an axial flow hydraulic turbine. This study focuses on an axial flow
Small Hydro Power, Hydraulic Turbine, Axial Flowhydraulic turbine operating near both the free and bottom surfaces in an open
Turbine, Performance Characteristics, Flow Field, Openchannel. We conducted a multiphase flow analysis that considers the free
Channel, Free Surface
surface, as well as a single-phase flow analysis that does not consider it. This
study indicates that the maximum power coefficient obtained from multiphaseflow analysis was lower than that obtained from single-phase flow analysis.
This is thought to be the result of the water-receiving area and inflow velocity
becoming smaller, the input power coefficient becoming lower due to the
influences of the free surface, and the bottom surface of the channel and theturbine efficiency becoming lower as the result of a non-uniform velocity
distribution.

Davood Khoeini, Ebrahim Shirani

In the present study, influences of impeller splitter blades on the performanceof a centrifugal pump when handling viscous fluids have been investigatednumerically and experimentally. In order to approach this aim, various splitterblades have been inserted on the impellers that pump viscous fluids ranging
from 1 cSt to 500 cSt and the optimum splitter blade length based on the
numerical results were constructed and tested thoroughly. Effects of splitterblades with lengths of 0.3, 0.45, 0.6 and 0.75 times of the main impeller blades
were analyzed numerically. Results revealed that splitter blades have significant Centrifugal pump, Splitter blades, Performance curve,
effect on the performance of a centrifugal pump. In fact, splittered impellers
Viscous fluids
extend the operating region of centrifugal pumps remarkably and also among
different surveyed splitter blades the head and efficiency increase by 20% and
3% respectively by using splittered impeller of 0.75L in comparison with theoriginal impeller (without splitter blade). Moreover, the data analyses showsthat splittered impellers can be used for pumping viscous fluids in the almost
all operating conditions of non-splittered impellers with less viscous working
fluid and obtained reasonable performance.

Chuang Li, Jianrun Zhang, Wenbin Yu

Kyung Hoon Kim

To solve the problem of excessive design parameters of flow channel during
the comprehensive optimization of the axial-flow blower's total pressure
efficiency and flux, a progressive optimization design method which is basedon the importance of structural parameters is proposed. The accurate
numerical simulation model of flow channel is built, verified and updated byexperiment results. According to the model, progressive orthogonal
optimization design is developed as following steps: the first is axial fan
design, then the orthogonal design of the structure parameters of entire flow
channel is further advanced. This approach is applied to the optimization
design of an axial-flow blower in this paper, and the results show that theuniformity of the flow field in the flow channel is significantly increased andthe vertexes spreading in the flow channel are obviously reduced, the flux isincreased from 0.145m3/s to 0.171m3/s, and the efficiency increased from45.47% to 58.13%, it indicates that the method can meet the design
requirements well while being efficient.

Axial-flow blower, High efficiency, Overall
optimization, Progressive orthogonal

Wall thinning is the reduction in pipe thickness as time passes, and can strain
pipes in nuclear or thermoelectric power plants. Wall thinning can be classified
into three types: flow-accelerated corrosion, cavitation erosion, and solid
particle erosion. This article presents a study on solid particle erosion, which
frequently causes damages to power plants' pipe strains. Unlike previous
Solid Particle Erosion (S.P.E.), Loss of Pipe Material,studies, this study uses a mechanism to make solid particles(micro scale) in a
Wall Thinning, Solid-Water Ratio, Particle Content,
fluid flow collide with pipe materials under water condition. Based on the
Erosion Rate, Water Condition
velocity change of the solid particles in a fluid flow, the surface changes, thechange in the amount of erosion, the erosion rate, and the variation in thehardness of carbon steel and aluminum strain pipe materials can all be
determined. In addition, factor-based erosion rates are verified, and a wallthinning relation function is suggested for the pipe materials.
Turbocharging is an important way to raise engine power density, save energy and reduce
emission. Because turbocharger is driven by exhaust gas, energy utilization rate is a key factor
for turbocharged engine performance. As a part transferring heat to mechanical energy,
turbine efficiency decides exhaust gas energy utilization. Because of three-dimensional flow
field distortion effect at outlet to exhaust manifold, turbine efficiency will be different from
MAP when engine working. Influences by interaction in turbine system, turbine efficiency will432-441

Study on Through-flow Model for Turbine System
Considering Three-dimensional Flow Field Distortion
Effectdecrease. So in order to evaluate turbine operating performance and design or select turbine

Yanbin Liu, Weilin Zhuge, Yangjun Zhang, Shuyong
Zhan

more precisely, it is necessary to build a through-flow model for turbine which can consider
three-dimensional flow field distortion effect.Unsteady flow field distortion at outlet to turbine

Engine, Turbine system, Through-flow model, Flowinteraction, Distortion model, Flow loss model

was analyzed and flow field interaction law between exhaust manifold and turbine was studied.
On the basis, six typical flow field distortion models in an engine operation cycle were raised.
Then influences six models on each flow stage in turbine were analyzed. Further, models forexhaust manifold and turbine were built separately. Difference between unsteady threedimensional simulation result and that based on turbine system through-flow model wascompared and analyzed. Research result illustrated that difference of turbine cycle efficiency
was only 0.1% and difference of turbine cycle work was 0.3%. So it can be deduced that

Page

1-11

12-21

Title

Instability Prediction of Valve Motion and Internal
Flow in Novel Large-scale Reciprocating Pump

AuthorYi Ma, Yutao Chen, He Zhang, Huashuai Luo,
Hongying Deng

Abstract

Keywords

To study the transient valve motions and flow pulsation of novel five-cylinder
double-acting reciprocating pump, the theoretical analysis and computational
fluid dynamics (CFD) method are employed to investigate the full-cycle
working process of the pump. The theoretical models describing the motions
and flow rates of hydraulic end are established for reciprocating pump under
the actions of piston and valves. The open-close behavior of suction anddischarge valves, internal turbulent flow and pulsation characteristics of theReciprocating pump, Dynamic grid technique,pump are studied and the effects of crank speed on those are analyzed in
Instability prediction, Valve motion, Flow pulsation
detail. The results show that the valves of reciprocating pump open and closequickly and non-linearly with various degrees of striking velocities and lag
phenomena. Through the time and frequency domain results of flow pulsation,
the single-cavity frequency is the dominant frequency. The most obvious
amplitude appears for discharge flow pulsation, which gradually increases withcrank speed. The results could provide useful information for the optimizationof reciprocating pumping systems.

The performance of the cone meter when measuring the cryogenic fluid wasinvestigated by numerical simulation. The results show that the dischargecoefficient and pressure loss coefficient of the cone meter are almost constantwhen the Reynolds number in the "stable region". The cryogenic fluids,
Performance of Cone Meter for Measuring Cryogenic Denghui He, Zhuang Chang, Bofeng Bai, Senlin Chen, especially the liquid hydrogen, have wider stable Reynolds number ranges
Cryogenic fluid, Cone meter, Discharge coefficient,
Fluid Considering Cavitation
Pengcheng Guo
than the water. There is little effect of cavitation on the discharge coefficient Pressure loss coefficient, Flow rate measurement
and pressure loss coefficient at the initial stage of cavitation. Thus the effect ofslight cavitation on the measurement error of the flow rate is small, whose
relative error is less than ±0.5% in present cases. This study opens a new
avenue for measuring the flow rate of the cryogenic fluid.

Cavitation is undesirable phenomenon and it is difficult to eliminate
completely, however it is minimized to the acceptable limits. It becomes more
severe under off-design conditions and lower tail race level. Shear Stress
Transport (SST) turbulence model and Rayleigh-Plesset mass transfer models

22-30

Cavitating Turbulent Flow Study for Low Head Francis
Turbine by Transient Analysis

Pankaj P Gohil, R P Sainiare used using CFX solver for performing the transient simulation andinvestigating the cavitation turbulent flow through Francis turbine. An attempt
has been carried out to analysis of cavitating flow at low head Francis turbine
under different operating conditions having varying suction heads.
Cavitation, Low head, Francis turbine, R-P model,
Experimentation has been carried out to validate the simulation results. It was Performance, Frequency
found that obtained simulation results are very close agreement withexperimental results. Summarizing, the performance loss and cavitation rate
are found maximum under over load operating conditions. At part load
operating conditions of the turbine, high amplitude of pressure at low
frequency has been found which may cause fatigue damage to the turbine
over time. Cavitation rate, performance loss and magnitude of pressure
pulsation increase with increase of suction head.

31-38

Experimental and Numerical Studies on Flow
Characteristics of Centrifugal Pump under Air-water
Inflow

Qiaorui Si, Wenting He, Gerard Bois, Qianglei Cui,
Shouqi Yuan, Keyu Zhang

39-46

IAHR 2018 Plenary Lecture 3 Changes in Hydro
Turbine Design - The Last 40 Years, and into The
Future -Stuart Coulson

A two-phase liquid pumping test ring is built to study the flow induced
characteristics of centrifugal pump under the air-water flow working
condition. Pump performances are measured under different flow rates
and different inlet air void fraction (a). Pressure pulsation signal
spectrums and their probability density maps are also recorded. The
calculations, using URANS k-epsilon turbulence model combined with
the Euler-Euler inhomogeneous two-phase model, are also performed
to obtain inner flow structure inside the impeller and volute channels
under different air-water conditions in order to understand the pumpcharacteristic evolutions. The results show that the performance ofcentrifugal pump is more sensitive to air inlet injection at low flow rates. two phase flow, centrifugal pump, flow characteristic,
Euler-Euler inhomogeneous model
The maximum air void fraction of model pump could reach 10% when
the pump operates at the highest efficiency point, and the performancedrops sharply when the air void fraction is more than 8%. The dominantfrequency of pump outlet pressure pulsation is still at the blade passing
frequency even under two-phase condition. Frequency amplitude
increases with the increase of a. The greater the a, the more of low
frequency appears in broadband characteristics. With the increase of a,the probability density amplitude of pressure pulsation decreases
gradually, and its span becomes gradually wider as well. Comparisons
between numerical local results and experimental unsteady pressure can
explain part of the phenomena that are found in the present paper.
In 29th IAHR symposium in Kyoto 2018, Mr. Coulson gave a lecture entitled "Changes in Hydro
Turbine Design - The Last 40 Years, and into The Future -" Recent runner design trends wereRunner, Blade, Design, Environment

overviewed. Future turbine techniques were also introduced.

Vol. 12,
No. 1,
JanuaryMarch,
2019

47-55

Pumped-Hydro Storages are Balancing Electric Energy
Production of Wind and Solar Reducing Average
Costs and Pollution

Aleksandar Gajic, Vladimir Stevanovic, Stan Pejovic

56-63

Numerical Simulation of a Gas-Liquid Centrifugal
Pump under Different Inlet Gas Volume Fraction
Conditions

Yan Sina, Luo Xingqi, Feng Jianjun, Zhu Guojun,
Zhang Lefu, Chen Senlin

The new world energy policy is influenced by climate changes, narrow range
of operation of Thermal Power Plants, potential risks of Nuclear Power Plants
and limited resources of oil, gas and coal. Taking into account that renewableenergy, solar and wind power particularly are very dependent on the climate,
Hydro Power takes a new role in energy systems. Electricity conversion andstorage in periods of lower consumption and electricity production from thestored energy in periods of higher demand or reduced production, are crucial
for the maintenance of stable and efficient electrical system. This requirement
has especially strengthened nowadays due to the expansion of integration of
new wind and solar plants. These renewable sources are characterized with
inherent intermittent production both in daily periods and periods of several
days, weeks or even months. A number of technologies might be consideredenergy system, balancing, hydro storage, renewables,
for the electricity conversion and storage, but the only nature and highaccumulation
capacity available technology is based on the pumped storage plants. This
article studies the potential of the pumped storage plants as the effective andeconomically competitive technology for the storage of wind, solar, run-ofriver and other environmentally friendly energies. Nuclear and coal fired plants
can change power output to achieve demand but only at the price of
extremely high maintenance cost. In addition, natural gas generators
contribute to climate change and pollution only slightly less than coal. The
pumped storage method is the most common storage system in the electricity
sector. It is traditionally dependent on natural conditions, usually making useof rivers or lakes. However, some innovative methods such as the use of thesea as the lower reservoir, or a proposal to use a surface reservoir as theupper reservoir and an underground reservoir as the lower have emerged.
In order to study the influence of inlet gas volume fraction (IGVF) on
performance of a gas-liquid centrifugal pump, three-dimensional turbulent
flow of a single-stage gas-liquid centrifugal pump has been simulated byusing computational fluid dynamics (CFD). Both steady and unsteadysimulations have been conducted for different inlet gas volume fraction
centrifugal pump, inlet gas volume fraction, gas-liquidconditions of the pump. The gas phase distribution, the internal flow field andtwo phase flow, CFD, performancepressure field of the pump were obtained with inhomogeneous two-fluid
model. The result showed that many gas accumulation zones accompanied
vortices appears in the impeller as IGVF increases, and surge would occur as
IGVF reaches a certain value. The change of IGVF would change themagnitude and direction of the impeller radial force.

64-70

This paper presents detailed analyses on the steady and unsteady internal flow
characteristics of a three-stage centrifugal pump under design and off-design
conditions. A numerical analysis is conducted by solving three-dimensional
steady and unsteady Reynolds-averaged Navier-Stokes equations with theshear stress transport (SST) turbulence model. The results of the steady andunsteady numerical analyses throughout the flow region are analyzed andcompared with experimental data. A reattachment modification is used in the
SST turbulence model to better capture the characteristics of flow separation
Steady and Unsteady Flow Characteristics of a MultiThree-stage centrifugal pump, steady analysis,
Jin-Hyuk Kim, Bo-Min Cho, Sung Kim, Yong-Kab Lee, due to boundary layer reattachment under the design and off-design
stage Centrifugal Pump under Design and Off-design
unsteady analysis, reattachment modification, design
Young-Seok Choi
conditions. The unsteady numerical results are in reasonable agreement with
Conditions
point, off-design point
the experimental data, whereas they differ from the steady numerical results
when it comes to the internal flow fields at each component stage. In
particular, the time-averaged internal flow phenomena obtained from theunsteady analysis are close to the real field conditions of this pump at low
flow rates. The hydraulic performances with and without the reattachment
modification are similar throughout the flow region, whereas the respective
flow characteristics in each impeller component are considerably different,
particularly at low flow rates.

71-88

An important flow mechanism that affects the performance and efficiency of
centrifugal pumps is cavitation. In recent years, many researchers have studied
the physics of cavitation in order to create appropriate detection
methodologies. The aim of this paper is to review the various experimental
tools that have been developed so far and enlighten the area of future
Cavitation, Experimental measurements, Flow
research on the field of cavitation monitoring. According to the results,
visualization and imaging, Machine diagnostics, Noise
cavitation detection is possible, but a large number of sensors have to be used and vibration measurements
and permanent changes in the machine need to be made for increasing theresults reliability. Therefore, future research steps are proposed towards thedevelopment of reliable, accurate but also easy to install and low costexperimental set ups.

A Review of Experimental Detection Methods ofCavitation in Centrifugal Pumps and Inducers

Georgios Mousmoulis, John Anagnostopoulos,
Dimitrios Papantonis

The present study investigated flow characteristics in the V-shaped region of
the suction performance curve for a double-suction centrifugal pump basedon the computational fluid dynamics (CFD). The V-shaped region in the time-

89-98

Flow Characteristics in a V-shaped Region of a
Suction Performance Curve in a Double-suction
Centrifugal Pump

averaged suction performance curve was simulated well. The CFD simulated
the fluid oscillations due to cavitation surge and rotating cavitation well. The
V-shaped region was observed in the absolute total pressure difference
between the impeller inlet and outlet. The time histories showed that the
Vorticity, Pressure loss, Torque, Angular momentum
Donghyuk Kang, Satoshi Yamazaki, Shusaku Kagawa,cavity produced vorticity, resulting in an increase in a pressure loss, and aflow rate, Suction performance curve, V-shaped
Byungjin An, Motohiko Nohmi, Kazuhiko Yokota
decrease in an impeller torque and an angular momentum flow rate. The time- region
averaged cavity volume, pressure loss between the impeller inlet and outlet,
vorticity in the blade passage and impeller torque were examined. A Λ shapeof a cavity volume curve caused a Λ shape of a vorticity curve, resulting in a Λshape of a pressure loss curve and a V shape of an impeller torque curve. TheΛ shape of the pressure loss curve and the V shape of the impeller torquecurve caused the V shape of the suction performance curve.

Page

99-108109-118

119-127128-135

Title

Simultaneous Optimization of Impeller and Volute ofa Single-channel Pump for Wastewater Treatment

Correlation of the Sediment Properties and Erosion in
Francis Hydro Turbine Runner

Optimization of Hydropower Plants Regarding Hydroabrasive Erosion

Suction Performance and Cavitation Instabilities ofTurbopumps with Three Different Inducer Design

AuthorExperimental and Numerical Investigation of the
Erosive Potential of a Leading Edge Cavity

Keywords

Jin-Hyuk Kim, Sang-Bum Ma, Young-Seok Choi,
Kwang-Yong Kim

Ujjwal Shrestha, Zhenmu Chen, Young Do Choi

Sediment erosion is the main problem for the hydropower situated in South
Asia and South America. Due to sediment erosion, hydropower in those areas
cannot operate in their full potential. Sediment erosion is a significant problem
in turbomachinery and associated with degradation of turbine performance.
The sediment erosion removes the turbine material from its surface. It cancause fracture of the turbine, which leads to an economic loss. In this paper,
the sediment properties and its influence on erosion have discussed. Sediment
properties like shape, size, and concentration have a direct influence on
Sediment, Erosion Model, Sediment Erosion, Shapeerosion. The numerical analysis was conducted to visualize the erosion in
Factor, Francis Hydro Turbine
Francis hydro turbine. The most vulnerable area for the sediment erosion in
Francis hydro turbine has predicted. The precise prediction of the sedimenterosion in the turbine is the difficult task due to the synergetic effect of
sediment parameters (shape, size, concentration, hardness, velocity). The
accurate and precise indication of the sediment erosion required bothexperimental and computational analysis. In this study, solid-fluid
computational analysis has done to identify the susceptible area on runnerblade and influence of sediment parameters on erosion.

Anant Kumar Rai, Arun Kumar, Thomas Staubli

The hydro-abrasive erosion poses challenges for smooth and eﬃcient
operation of existing hydropower plants (HPPs) as well as planning for new
HPPs. The loss in revenue is caused due to reduced generation on account of
reduced efficiency, down time for repair and maintenance for restoring themachinery and other components. In this study, various optimizationconsiderations required with respect to hydro-abrasive erosion at both theplanning and the operation stage of a HPP are presented. The factors involvedin each steps like unit sizing, selection and design of turbines, capacity ofHydraulic Turbine, hydro-abrasive Erosion, Suspended
desanders, cut-off limits of sediment concentration for turbine switch-offs,
sediment, Efficiency, Optimization, Hydropower
preventive measures such as coatings etc. were discussed. Further, a case studyof an operational HPP located in Indian Himalayas is presented where
suspended sediments, hydro-abrasive erosion and reduction in efficiency were
measured simultaneously. Available models were used with measured values toobtain various losses due to hydro-abrasive erosion. The cost of coating, apreventive measure, is compared with the losses in operating the uncoatedturbine. A decision making criterion is also introduced.

Tatsuya Morii, Yohei Tanaka, Satoshi Watanabe,
Satoru Ohashi, Yasushi Matsunaga

In the present study, the suction performance and the cavitation instabilities inturbo-pumps with three different inducers designed with different design
incidence angle are experimentally investigated in the wide range of operating
flow rate. Three inducers L with the lowest design incidence angle, M with themoderate one and H with the largest one are used in combination withidentical main impeller. As a result, the total head of pump with inducer H isconfirmed to be the largest especially at large flow rates, while the shaft poweris almost the same, resulting in the best efficiency with the inducer H. The
Cavitation, Turbopump, Inducer, Cavitation
suction performance is the best with inducer H at large flow rates and is the performance, Design incidence angle
best with inducer L at low flow rates. Two kinds of instabilities, the cavitating
whirling vortex and the surges are mainly observed for the all both inducers,
but they are limited at low flow rates. The occurrence ranges of these
instabilities in terms of the operating flow rate is the widest with inducer H.
However, those in terms of the shockless flow rate ratio is similar for the all
three inducers: This fact can contribute to establish some guideline to thepump operation avoiding serious flow instabilities.

Jean-Bastien Carrat, Regiane Fortes-Patella, JeanPierre Franc

This paper presents a joint experimental and numerical analysis of the erosive
potential of an unsteady cavity that develops at the leading edge of a twodimensional hydrofoil and periodically sheds vapour clouds. From anexperimental viewpoint, the erosive potential was characterized by pressure
pulse height spectra. The hydrofoil was equipped with eight pressure sensors
made of PVDF piezoelectric film that allowed the measurement of flow
aggressiveness at different locations along the hydrofoil chord. It was shownthat the mean peak rate over a large number of cavity pulsations exhibits amaximum at a distance from the leading edge close to the maximum cavity
length. Moreover, the increase in flow aggressiveness caused by an increase inflow velocity can be explained by an increase in both amplitude and frequencyof impact loads. From a numerical viewpoint, the unsteady Reynolds averaged Fluids dynamics, Cavitation erosion, Numerical
Navier-Stokes (RANS) equations were solved using a modified k-ε RNG
calculations, Experimental measurements, Unsteadyturbulence model together with a homogeneous cavitation model within apressure measurements, PVDF sensors
two-dimensional approach. Flow aggressiveness was estimated from the
Lagrangian derivative of the computed void fraction that allows identifying theregions of collapse of vapour structures. Three different critical regions froman erosive viewpoint were numerically identified. Apart from the region ofcollapse of the shed cloud (which was not instrumented in the present study),
the computations showed a maximum of aggressiveness around the maximum
cavity length as found experimentally. Another region of high aggressivenesscloser to the leading edge and associated to the upward movement of the reentrant jet was predicted by the present numerical model but not confirmed
experimentally, which probably shows the limitation of a two-dimensional
approach.

Vol. 12,
No. 2,
April-June,2019

136-146

Abstract

The impeller and volute of a single-channel pump used for wastewater
treatment were simultaneously optimized to improve the hydraulic efficiency
and reduce unsteady radial force sources due to impeller–volute interaction.
Steady and unsteady Reynolds-averaged Navier–Stokes equations were solved
with the shear stress transport turbulence model as the turbulence closure
model using tetrahedral grids to analyze the internal flow in the single-channel
pump. Five design variables related to the internal flow cross-sectional areas of
the impeller and volute were selected to simultaneously optimize threeobjective functions: the hydraulic efficiency, the sweep area of the radial force
during one revolution, and the distance of the mass center of the sweep area
Single-channel pump, optimization, radial force,from the origin. A response surface approximation model and a genetic
sweep area, efficiency, unsteady RANS
algorithm were employed to obtain the three-dimensional Pareto-optimal
solutions representing the trade-off between the efficiency and the radial force
sources. The three-objective optimization results showed that the
representative clustered optimum designs exhibit enhanced efficiency andreduced radial force sources simultaneously in most cases, compared with thereference design. The trade-off relationship between the efficiency and theradial force sources clarifies with controlling the internal flow cross-sectional
areas of the impeller and volute of the single-channel pump. The efficiency
improvement and reduction in the radial force sources were systematicallyverified by analyzing the detailed internal flow characteristics.

The CATHARE-3 predictive transient rotodynamic pump model and its
validation in single-phase first quadrant conditions at component scale arepresented in this paper. One-dimensional discretization and resolution of
governing equations are made according to a mean flow path along all pump
Modelling of a Centrifugal Pump Using the147-158 CATHARE-3 One-dimensional Transient Rotodynamic
Pump Model

Laura Matteo, Antoine Dazin, Nicolas Tauveron

parts (suction, impeller, diffuser, volute and discharge pipe), what makes themodel original compared to classical 1D models. The model is first verified byrotodynamic, pump, transient, model, CATHARE-3,
comparison to the Euler equation of turbomachinery results. Then, qualification
predictionof the model is carried out in steady and transient conditions by comparison
to available experimental data. Head and torque characteristics curves are well
predicted at different rotational speeds. Finally, a fast startup transient issimulated. Results are satisfactory as the difference between the experimental
and modelled non-dimensionalized head is less than 10% of the final value
during the whole startup.

Rotor stator interaction in high-head Francis turbines has led to several failures in recent years.
Increasing efficiency demands require design optimization of the turbine components, which
may lead to thinner profiles. Not only can component not withstand the given loads; quite
often one or more of their natural frequencies coincide with that of the rotor-stator
interaction. Most of the research published has been on runners, while other parts of theturbine are less studied. Even though guide vanes have torsional modes with frequencies

159-168

On the External Effects Affecting Torsional Modes in
Guide Vanes

which may be close to the exiting frequency from the rotor stator interaction with the runner,

Petter T K Østby, Eivind Myrvold, Jan Tore Billdal, Bjø
no significant failures due to resonance have been reported. This paper investigates some of
rnn Haugenthe possible mechanisms which may negate resonance in the torsional modes of the guide

RSI, guide vane, vibration, resonancevanes including; hydrodynamic damping from the flowing water and friction in the guide vane
bearings. A case study is conducted on a guide vane where the calculated natural frequency is
within 10% of the excitation frequency, while no significant vibrations have been reported.
Further, the findings are generalized to Francis turbines of different specific speeds. The results
indicate that the dynamics in the bearings are especially important to consider to be able topredict the vibration levels of the guide vane. Having the correct friction factor in the bearing

169-180

Three-Dimensional Theoretical Study on Flow
Characteristics of a Spiral-Channel Viscous
Micropump

Donghyuk Kang, Koichi Nishibe, Kotaro Sato,
Kazuhiko Yokota

Page

Title

Author181-188

189-199

Simulation Studies on the Hemodynamics of aCentrifugal Ventricular Assist pump

Investigation of Unsteady Pressure Pulsation andInternal Flow in a Centrifugal Pump under Low Flow
Rate

200-216 On the High-partial-load Pulsation in Francis Turbines

Measurements on a Model Francis Turbine duringStart-Stop

Abstract

Keywords

The present study was aimed to reveal the possible interactions between theleft ventricular assist pump and the blood. The study presented in here
adopted the computational fluid dynamics approach to analyze the effects ofvariations in blade height, rotation speed, and suspension height on the
dynamic performance of the left ventricular assist pump. In addition, the 3D
printing technology was tested as a reliable of manufacture of the assembly
parts the left ventricular assist pump. The study was designed and conducted
only after system debugging was accomplished. The computer-aided
simulation results showed that the blade height, rotation speed andLeft ventricular assist pump, Computational fluid
Haiquan Feng, Dong Wang, Kun Wang, Mingxin Zhu
suspension height had varied functional on the dynamic performance of the
dynamics, Wall shear stress, 3D printing
device. Comparison of the influence degree of each factor to that of the bloodindicated that rotation speed has the largest impact, followed by the blade
height and finally the suspension height. At the same time, the experimental
results proved that the design principle was rational and if prepared the left
ventricular assist pump could operate successfully. The computer-aided
simulation and experiment also reproduced the possible effects of the various
factors on the blood and provided a theoretical reference for the design of thecentrifugal ventricular assist pump.

Qifeng Gao, Jun Ye, Bingfeng Wang, Jin Zhao

In order to study the unsteady pressure pulsation and internal flow in acentrifugal pump under low flow rate, numerical calculation of a centrifugal
pump was carried out. The accuracy of the numerical calculation method wasverified with the external characteristic test. The characteristics of the unsteadypressure pulsation and internal flow of the centrifugal pump were analyzed indetail. The results show that the interaction between the impeller and thevolute has a significant effect on the unsteady pressure pulsation of thecentrifugal pump, pressure pulsation, vortex,
centrifugal pump. The essential reason of the periodic pressure pulsation was numerical calculation
explained, and the evolution of separation vortex formation and collapse in
the impeller was presented. Regulation of the generation and development of
the high pressure zone in the volute was revealed. With the reduction of theflow rate, the influence of the low pressure zone in the impeller is enhanced
and the pressure near the volute tongue is decreased. The results can providea reference for the centrifugal pump design and optimization

Peter K. Dörfler

Francis turbines with high specific speed may produce intense pulsations ofsystem pressure when operating at approximately 70-85% of best-efficiency
discharge. Frequencies between 1 and 4 times runner rotation are typical. The
paper recalls and explains the particular set of properties. The pulsation is due
to instability of the second-lowest eigenmode of the hydraulic system
containing a cavitating draft tube vortex. A 1D model in frequency domain isused - with emphasis on the crucial role of the finite velocity of swirl
propagation - to show how this mode can become unstable and give rise to a Francis turbine, draft tube surge, vortex cavitation,strong ‘breathing’ pulsation. A parameter study shows the well-known
high partial load, stability, mass-flow gain
influence of draft tube pressure and why the behavior of prototype turbines isoften different from the reduced-scale model. Some of the phase properties
are explained by a 2D acoustic model. The phase reversal between upstream
and downstream pressures is a consequence of the mode shape, with roughly
two quarter waves of pressure along the cavitating vortex rope. The stability isquite sensitive to 2D effects; therefore the present 1D model, while useful forunderstanding the phenomena, is not likely to permit reliable predictions.

Rahul Goyal, B K Gandhi, M J Cervantes

Increased penetration of intermittent energy resources disturbs thepower grid network. The frequency band of the power grid is normallycontrolled by automatic opening and closing of the guide vanes ofhydraulic turbines. This has increased the number of startup andshutdown cycles as compared to the defined ones for the normal
operation of turbines. Turbine startup and shutdown induced a higher
level of pressure fluctuations and unsteadiness in the flow field,
decreasing its expected life. This paper presents the pressure andvelocity measurements performed on a Francis turbine model during
Francis turbine, startup, shutdown, particle image
startup and shutdown. The pressure measurements were performed invelocimetry, pressure measurements, rotor-stator
the vaneless space and draft tube and two-dimensional particle image
interaction, flow dynamics
velocimetry measurements in the cone. The turbine operations from astandstill (no flow) and high load were considered to perform thestartup and shutdown, respectively. The frequency of rotor-stator
interactions and standing waves were well captured in the spectrogramsof pressure signals. The signature of rotating vortex rope frequency was
also observed in the spectrograms. A huge disturbance in the draft tube
flow was observed due to these transient operations. The flow at thecenter was mainly dominated by the stagnant, separation andrecirculating regions.

Vol. 12,
No. 3,
JulySeptember, 2019217-227

Technological developments have led to micropumps playing an ever-greaterrole at the heart of micro total analysis systems. Spiral-channel viscousmicropumps have been studied theoretically, numerically, and experimentally.
However, high-accuracy performance predictions have not been achieved overa wide range of operating conditions. The present study proposes threeMicropump, Viscosity, Spiral channel, Pump
dimensional and quasi-three-dimensional theoretical expressions for predicting
performance, Three-dimensional analysis, low
the pressure performance of spiral-channel viscous micropumps in lowReynolds number
Reynolds-number environments. The theoretical analysis is validated through aseries of comparisons with numerical simulation results for the pressure
performance curves, velocity distributions, velocity gradient distributions, andchannel internal pressure distributions. Furthermore, the influence of thechannel aspect ratio on the performance characteristics is investigated.

In an oscillating water column (OWC) based wave energy plant, a bidirectional airflow is generated in the air chamber. To harness energy,
the bi-directional airflow turbines that rotate in the same direction areused in such wave energy conversion devices. Some turbines for bidirectional airflow have been proposed to date, and their performance
Manabu Takao, Seisuke Fukuma, Shinya Okuhara, M. were investigated by wind tunnel tests and CFD analyses. Some of the
Fluid Machinery, Impulse Turbine, Wells Turbine,
228-234 A comparative study of bi-directional airflow turbines
M. Ashraful Alam, Yoichi Kinoue
Wave Energy Conversion, Bi-directional Flow
typical turbines have inherent disadvantages, such as severe stall
problem and low efficiency. Therefore, authors proposed two uniqueturbines for bi-directional flow: Wells turbine with booster and counterrotating impulse turbine. An extensive computational work was
conducted to perform a comparative study between the conventional
and proposed turbines for bi-directional airflow.

235-243

One-way Coupling Numerical Simulation of Cryogenic
Cavitation Around an Inducer

Yu Ito, X Zheng, Takao Nagasaki

To numerically simulate cryogenic cavitation of turbomachinery, amathematical model was developed, combined with the bubble size
distribution model and Rayleigh–Plesset and heat conduction equations. In the
bubble size distribution model, the bubble growth/decay was solved for eachclass of bubble mass when bubbles with various masses mixed in the same
spatially discretized calculation region. The bubble growth/decay calculations
Bubble size distribution, Rayleigh–Plesset equation,
included a combination of the Rayleigh–Plesset equation for the bubble
Thermal boundary layer, OpenFOAM
oscillations and heat conduction equation in a thermal boundary layer arounda bubble, to evaluate the evaporation or condensation mass rates. This study
demonstrated that the cavitation mathematical model has the potential tocontribute to the simulation fidelity for turbomachinery for a fluid with strong
thermodynamic effects.