bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Numerical Study on Performances of Centrifugal Compressor Stages With Different Radial Gaps
Authors: Sato K. , He L. 
Published: August 2014

A numerical study of 3D unsteady flows in centrifugal compressor stages solving the Navier-Stokes equations is presented. The emphasis is on the effect of the radial gap between blade rows on the aerodynamic performance. In the numerical tests, Krain’s centrifugal impeller was combined with a DCA (Double Circular Arc) type radial vaned diffuser. The compressor stages with three settings of radial gap ranging from 5 to 15 percent of the impeller trailing edge radius are configured and unsteady flow simulations are carried out to compare the time-averaged efficiencies.
The performance predictions show that the efficiency is deteriorated if the radial gap between blade rows is reduced with intensified blade row interaction, which is in contradiction to the general trend for axial compressor stages. In the centrifugal compressors tested, wake chopping by diffuser vanes, which usually benefits efficiency in axial compressor stages, causes unfavourable wake compression through the diffuser passages to deteriorate the efficiency.
Influence of Endwall Contouring in Axial Gaps on the Flow Field in a Four-Stage Turbine
Authors: Bohn Dieter E. , Kusterer Karsten , Sürken Norbert , Kreitmeier Franz 
Published: August 2014

Secondary flows and leakage flows are leading to complex vortex structures in the 3-D flow field of a turbine blading. Aerodynamic losses are the consequence. Reducing the aerodynamic losses related to tip leakage flows by endwall contouring is subject of an actual numerical investigation of the flow field in a 4-stage test turbine with repeating stages. The 3-D flow field for various geometric configurations with endwall contouring is calculated by application of a 3-D Navier-Stokes code. Here, the numerical results of configurations with arc-like and wave-like contours (bumps) at the shaft and the casing with a maximum deviation from the reference contour in the axial gap between stator and rotor are presented. Furthermore, the results are compared to the experimental and numerical data of the test turbine with a reference contour without endwall contouring.
The results show a significant influence of the bumps on the radial velocity distribution in the flow field and the static pressure field. By application of a subtraction method where the reference flow field is subtracted from the flow fields of the bump-configurations, it can be shown that the leakage flows are reduced. A detailed flow analysis shows the presence of a leakage vortex.
For a measure of the flow field inhomogeneity and for reducing the complex 3-D data to 2-D and 1-D values a balance-based averaging method is used. The method is based on a hypothetical equilibration process between two infinitesimal neighbouring control surfaces. During this physically based averaging process, equilibration coefficients can be derived which are a measure for the flow inhomogeneity. It can be shown that arc-like and wave-like endwall contouring has a positive influence on the homogeneity of the flow field. Thus, this effect leads to higher aerodynamic stage efficiencies for repeating stages.
Numerical and Experimental Investigation of an Aerodynamically High-Loaded Axial Boiler Fan
Authors: Reischke A. , Jung M. , Breuhaus P. , Molin J. , Hess S. 
Published: August 2014

In a common project ABB Fläkt Industri AB, Sweden, and ABB Turbo Systems Ltd., Switzerland, developed a Q3D design system for low Mach number axial fans. In order to validate the Q3D-calculations and the customized loss correlation, the flow field of an industrial high-pressure boiler fan was investigated experimentally.
The examined single stage fan is equipped with hydraulically adjustable rotor blades, non-profiled guide vanes and an annular diffuser. Varying the stagger angle between 34° and 76° allows operating the fan over a wide range of volume flows. Experiments and calculations cover the entire stable operating range.
Flow field traverses by means of hot film anemometry and pneumatic total pressure Kiel probes at different sections within the rotor/vane configuration, combined with axially and tangentially distributed static pressures tabs and fix mounted Kiel probes, allowed a deep insight in the flow behavior. The fast response capability of the hot film anemometry was used to measure the flow field downstream of the rotor in detail. Additionally, flow field visualizations inside the guide vane channel based upon a TiO4/Oil-paint technique completed the experimental fan investigation.
The Q3D system is based on coupling the Euler codes MISES (S1) and MTFlow (S2), both developed at MIT. Loss models were implemented to account for profile losses, leakage losses and endwall losses. Near wall viscous effects are considered by boundary layer modeling.
The investigations show that the S1/S2 Euler solvers behave well even in case of Mach numbers below 0.03. S1 convergence problems arise for off-design cases because of unfavorable incidence angles. The fully automated Q3D systems allows calculating fan performance charts with low turnaround time in good agreement with the measurement.
Control of Combustor Instabilities Using an Artificial Neural Network
Authors: Vaudrey Michael A. , Saunders William R. 
Published: August 2014

It is well-known that phase-shifting controllers used for active combustion control must be manually adjusted in order to maintain control over a broad range of operating combustor operating conditions. If one assumes that the thermoacoustic instabilities are linearly stabilizable, then what is needed is a method to determine, and ultimately predict, the frequency response of the plant for any range of operating conditions, so the controller design can be automatically updated to track the changing plant gain/phase relationships that are observed with changing heat release. A unique test-based, design process has been proposed to predict the gain/phase characteristics required of a proportional, phase-shifting controller that can stabilize the thermoacoustic instabilities. In this paper, that process is used to automate the design of a fixed-gain feedback controller that limits the amplitudes of any feedback induced instabilities (to some pre-specified level) while providing the best control of the targeted limit cycling pressure oscillations.
The paper describes how a neural network was trained, using the suggested design process, to predict the frequency response of the thermoacoustics in a tube combustor at frequencies adjacent to the limit cycle frequency using certain operating conditions that included a sparsely-sampled temperature profile, total air/fuel flow rate, and equivalence ratio. The neural net training was performed using complex valued, open-loop frequency response function data as the desired signal with the previously mentioned operating conditions as the input signals. (The open loop data was collected for a narrow frequency range surrounding the limit cycle instability by performing a sine dwell at discrete frequencies). Once the neural network was trained, it was used to predict the approximate phase and gain margins as a function of temperature and flow conditions. The margins were then used to automatically update and design a fixed shape feedback controller having the proper phase and magnitude to ensure stability and control in the face of changing operating conditions. A companion paper describes the methodology that underlies the automated design of the feedback controller gain and phase delay.
Development and Evaluation of Ceramic Components for Small Gas Turbine Engine
Authors: Tanaka Koichi , Yoshida Makoto , Kubo Toshifumi , Terazono Hirofumi , Tsuruzono Sazo 
Published: August 2014

The 300kW class CGT project in Japan administered by the New Energy and Industrial Technology Development Organization (NEDO) under the sponsorship of the Ministry of International Trade and Industry (MITI) was completed in March, 1999 after 11 years. The purposes of the project were energy conservation and environmental protection. The CGT302 group of the CGT project, in cooperation with Kawasaki Heavy Industries, Ltd. (KHI), achieved all of the project targets. The targets included the turbine inlet temperature (TIT) of 1350°C, a thermal efficiency of 42%, emissions below 70ppm, and a 1000hr engine durability test carried out at 1200°C1).
To achieve such targets Kyocera has been developing various ceramic components such as large-sized stationary components, monolithic rotors and ceramic shrouds with abradable seal. These components have been successfully fabricated with SN281 and SN282. Damage was caused as a result of contact between the turbine blades and the shrouds. In order to reduce such damages, the shroud has been modified to incorporate an abradable material newly developed for this application, and an engine test has been carried out successfully with no damage.
For practical use, the greatest concern is the durability of ceramic components. The ceramic components were evaluated in a 1000hr long term durability test. There were, however, some troubles for the GGT rotors and the engines were broken when the durability tests were carried out. Finally, only the combustor survived the 1000hr engine test at 1200°C. The material characteristics of the survived combustor along with other broken components were analyzed after the long-term engine tests. The test results revealed no obvious change in mechanical properties nor in blade shape.
In this paper, the development of selected components is presented along with the evaluation results of components exposed to the long-term engine tests.
Effects of Gap Leakage on Fluid Flow in a Contoured Turbine Nozzle Guide Vane
Authors: Lin Y.-L. , Shih T. I-P. , Chyu M. K. , Bunker R. S. 
Published: August 2014

Computations were performed to study the three-dimensional flow in a nozzle guide vane with leakage issuing from a narrow gap with a backward-facing step located upstream of the airfoil on each endwall. The nozzle guide vane investigated has one flat and one contoured endwall. For the contoured endwall, two configurations of the same contouring profile were investigated with and without gap leakage. In one configuration, all contouring is upstream of the airfoil passage. In the other, the contouring starts upstream of the airfoil passage and continues through it.
Results obtained show that when there is gap leakage, secondary flows are reduced at all endwalls for both nozzle configurations investigated. Without gap leakage, secondary flows are reduced only on the contoured endwall in which the contouring started upstream of the airfoil passage and continued through it. When all of the contouring is located upstream of the airfoil passage, there is considerable hot gas ingestion into the gap at both endwalls. When the contouring starts upstream of the airfoil passage and continues throught it, hot gas ingestion was minimal at the contoured endwall and greatly reduced at the flat endwall.
This computational study is based on the ensemble-averaged conservation equations of mass, momentum (compressible Navier-Stokes), and energy. Effects of turbulence were modeled by the low Reynolds number shear-stress transport k-ω model. Solutions were generated by a cell-centered finite-volume method that uses third-order accurate flux-difference splitting of Roe with limiters and multigrid acceleration of a diagonalized ADI scheme with local time stepping on patched structured grids.
The Engineering Doctorate — An ‘Enhanced’ Doctoral Programme for Engineers Incorporating Business Decision-Making Skills: A Gas-Turbine Engineering Perspective
Authors: Ivey Paul C. , Sanderson Michael L. , Morris Vivien , Ferguson Derek G. 
Published: August 2014

This paper describes a new UK initiative in the post graduate education of Engineers. The new ‘enhanced’ degree of Engineering Doctorate educates graduate Engineers in their respective technical disciplines whilst at the same time integrating the world of commerce and business into the technical decision making process.
The paper describes the initial candidate selection methodology, project selection, course structure, assessment, thesis structure and outputs. The advantages of this enhanced postgraduate training are demonstrated, as are the objectives for the UK in adopting such a scheme.
An example is presented from a joint Rolls Royce / Cranfield case study of the Design, Development and Product launch of a new type of Gas Turbine Instrumentation. This is set in a Gas Turbine Engineering perspective, in particular the consideration of active control of compressor surge to benefit aircraft engine fuel burn and increased flight range.
Experience With a Fast Track Power Generation Project
Authors: Mayer Albrecht H. , Lively Noel W. 
Published: August 2014

To meet peaking power demands the E.W. Brown Station, owned and operated by Kentucky Utilities Company, was extended by two GT24 gas turbines. The project had to meet a 9-month engineering, construction and commissioning schedule. The conceptual design is based on ABB ALSTOM POWER’S reference plant design for combined cycle application. It was adjusted to the requirements of a simple cycle operation.
Special plant features such as evaporative cooling of the inlet air, system design of the evaporative cooling system, performance and experience will be discussed in detail. The plant has an aggressive running and starting reliability goal; the approach to meet the required plant reliability will be discussed below. The initial operational feedback will be addressed as well as an outlook on how to meet all project goals.
WR21 Intercooled Recuperated (ICR) Gas Turbine Engine System Level Development Test Program Summary
Authors: Janton Jay T. , Uawithya Chai 
Published: August 2014

The WR21 Intercooled Recuperated (ICR) Gas Turbine engine has undergone system level development testing from July of 1994 to December 1999. There have been a total of ten engine builds and 2126 hours of engine operation performed through December of 1999. A significant number of unique development tests (experiments) have been performed over the ten engine builds. The last development test just completed and that was a USN specified 500-hour endurance test from 4 October through 16 December of 1999.
All the development testing to date has been performed at the Defense Evaluation and Research Agency (DERA), Pyestock, England which is part of the UK Ministry of Defense (MOD). The last 500-hour endurance test was performed at the Advanced Propulsion & Power Generation Test Site (APPGTS) located at the Naval Surface Warfare Center Carderock Division (NSWCCD), Philadelphia, PA. The system level testing performed has evaluated the gas generator, power turbine, enclosure systems, recuperator, intercooler, and engine electronic controller (EEC). The enclosure systems include two off-engine skids (lube oil module and Intercooler Heat Exchanger module), accessory gearbox, fire protection system, enclosure cooling system, water wash, structureborne and airborne noise, fuel system and air start system.
A three-phase development test strategy was employed. The first phase was to demonstrate the ICR technology and identify the highest-risk areas. Due to the unique challenges introduced by the intercooler, recuperator, variable area nozzles, and new EEC the test program was continually reviewed and revised. The second phase focused on component and system improvements. The final phase is the verification of the ICR in a 500-hr endurance test. At the completion of development testing a final design review will be held (DR5), followed by qualification testing. The qualification tests will include a 3150-hr endurance test and shock test. This paper summarizes and discusses the major tests performed during the development phases. The plan for the final development 500-hr endurance test and 3150-hr qualification test will be presented.
Life Extending Advanced Component Repairs — Field Operating Experience
Authors: Cooke Lloyd A. 
Published: August 2014

Advanced repair technologies have been introduced to the gas turbine industry over recent years. An increasing selection of coating systems is available which can be tailored to the specific operating environment. Automated welding systems and the use of custom weld filler metals for enhanced component life provide a means of reliably welding the new generation of high strength turbine blade alloys. Powder metallurgy processes have been introduced as an alternative to welding and have been used to upgrade certain components by employing higher strength repair materials than the original castings.
In the paper, these and other technologies are assessed based on engine operating experience with direct comparison to the conventional repair techniques which they have replaced.
25-5 Kwe Microturbine Design Aspects
Authors: Rodgers C. 
Published: August 2014

In concert with the growing emphasis placed on distributed power generation there will be a need, in the first decade of the 21st century, for a compact thermal energy system capable of providing the total energy needs of individual homes. A natural gas fueled cogeneration microturbine with ultra low emissions will meet this need.
The results of a study to assess the thermal and economic aspects of microturbines in the 25 to 5 Kwe range are presented. It was determined that with current state of art component peak performance levels, and metallic materials, thermal efficiency goals of 27 and 22.5% respectively at sea level standard day conditions are attainable. Higher overall thermal efficiencies of 60% are attainable with a microturbine combined with a fuel cell, and approaching 80% combined with exhaust fired boilers.
Development of a low cost natural gas combustor injection method, combined with a low cost high effectiveness recuperator were considered mandatory for market acceptance.
Three-Dimensional Investigations for Axial Turbines by an Implicit Unstructured Multi-Block Flow Solver
Authors: Adami P. , Martelli F. , Michelassi V. 
Published: August 2014

An unstructured 3D implicit approach (HybFlow) is briefly described for gas turbine applications. The numerical approach is based in an upwind finite volume scheme with an implicit time marching algorithm. The linear solver is GMRES with right preconditioning obtained by the ILU(0) incomplete factorization. A two k-w turbulence model is considered for viscous flows. The new multiblock extension of the code is here considered for improving the computational efficiency of the basic procedure in view of the application to complex 3D geometries. Particular concern has been placed in the new approach for memory saving while keeping at the same time a great geometrical flexibility and grid transparency. The strategy developed is therefore described considering the whole process and all phases required in the solution of internal flows.
Both memory and CPU time costs are addressed to verify the performances of the multiblock scheme as also computational accuracy for 2D tests. The flow conditions investigated range from the low speed regime up to the transonic one to prove the accuracy of the approach using hybrid unstructured configurations. Finally the application to the transonic cooled annular IGV blade row is considered to assess the multiblock strategy for a 3D case.
Research and Development of Practical Industrial Cogeneration Technology in Japan
Authors: Abe Toshiaki , Sugiura Takashi , Okunaga Shuji , Nojima Katsuhiro , Tsutsui Yasukata , Matsunuma Takayuki 
Published: August 2014

This paper presents an overview of a development project involving industrial cogeneration technology using 8,000-kW class hybrid gas turbines in which both metal and ceramics are used in parts subject to high temperatures in order to achieve high efficiency and low pollution.
The development of hybrid gas turbines focuses mainly on the earlier commercialization of the turbine system. Stationary parts such as combustor liners, transition ducts, and first-stage turbine nozzles (stationary blades) are expected to be fabricated from ceramics. The project aims at developing material for these ceramic parts that will have a superior resistance to heat and oxidation. The project also aims at designing and prototyping a hybrid gas turbine system to analyze the operation in order to improve the performance. Furthermore, the prototyped hybrid gas turbine system will be tested for long-term operation (4,000 hours) to verify that the system can withstand commercialization. Studies will be conducted to ensure that the system’s soundness and reliability are sufficient for industrial cogeneration applications.
In-Duct Measurement of Gas Turbine Noise Emmisions Using a Cross Spectrum Method
Authors: Sacks M. P. , Kawall J. G. , Behboudi R. , Buttell J. 
Published: August 2014

It is often desirable to measure the sound power radiated by the inlet or exhaust of a gas turbine in an installation that includes filters and silencers. A direct measurement can only be accomplished within the empty duct between the inlet or exhaust flange and the silencer. For a number of reasons ISO 5136 [1] cannot be used directly to perform these measurements. Consequently, some other means must be found.
The primary requirement for an in-duct sound power measurement is a valid in-duct sound pressure measurement. In order to accomplish this, the effect of the turbulent pressure fluctuations inherent in the flow, or induced by the microphone probes, must be removed from the dynamic pressure signals sensed by the microphone.
This paper describes the use of a two-microphone cross amplitude spectrum (CAS) technique to perform accurate measurements of the autospectra of sound fields embedded in turbulent duct flows. This technique is based on the assumption that the acoustic and turbulence signals detected by any microphone are uncorrelated with each other and also with the turbulence signals detected by another microphone.
The paper gives the measurement parameters required for various degrees of turbulence rejection as well as the accuracy and convergence of the estimate of the embedded acoustic spectrum. The paper also provides a means to determine the microphone separation distance required to ensure that the turbulence signals at the two microphones are uncorrelated. These results are based on both the simulation of acoustic fields embedded in turbulence and on laboratory experiments using both loudspeakers and an aeroacoustic wind tunnel.
Typical results show that for practical measurement durations the proposed method will provide a turbulence rejection in octave bands of approximately 15 dB at 31.5 Hz rising smoothly to 25 dB at 8 kHz. The method thus appears to have some distinct advantages over ISO 5136 methodology.
Draft Whole-Genome Sequence of OXA-48-Producing Multidrug-Resistant Klebsiella pneumoniae KP_ST11_OXA-48
Authors: Villa Jennifer , Viedma Esther , Brañas Patricia , Mingorance Jesús , Chaves Fernando 
Published: August 2014

ABSTRACT

We present the draft genome sequence of a blood culture isolate of OXA-48-producing
Klebsiella pneumoniae
(sequence type 11 [ST11]) obtained in the course of a hospital outbreak in Spain. Sequence analysis showed 121 genes related to antibiotic and antiseptic resistance, including
bla
OXA-48
, which was located in an IncL/M plasmid.
Genetic Characterization of a Natural Reassortant H3N8 Avian Influenza Virus Isolated from Domestic Geese in Guangxi, Southern China
Authors: Liu Tingting , Xie Zhixun , Song Degui , Luo Sisi , Xie Liji , Li Meng , Xie Zhiqing , Deng Xianweng 
Published: August 2014

ABSTRACT
A H3N8 subtype of avian influenza virus, A/goose/Guangxi/020G/2009(H3N8) (GX020G), was isolated from the Guangxi Province of China in 2009. All eight gene segments of the GX020G strain were sequenced. Sequence analysis indicated that this H3N8 virus is a novel reassortant strain. The genome sequences provide useful information for understanding the epidemiology and molecular characteristics of the H3N8 subtype of influenza virus in southern China.