bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Dimensional Rotational Flow in Transonic Turbomachines: Part II — Full 3D Flow in CAS Rotor Obtained by Using a Number of S1 and S2 Stream Filaments
Authors: Chung-Hua Wu , Xiaolu Zhao , Lisen Qin
Published: March 2015

The general theory for three–dimensional flow in subsonic and supersonic turbomachines has recently been extended to transonic turbomachines. In Part II of the paper, quasi– and full three–dimensional solutions of the transonic flow in the CAS rotor are presented. The solutions are obtained by iterative calculation between a number of S1 stream filaments and, respectively, a central S2 stream filament and a number of S2m stream filaments. Relatively simple methods developed recently for solving the transonic flow along S1 and S2 stream filaments are used in the calculation.

The three–dimensional flow fields in the CAS rotor obtained by the present method are presented in detail with special emphasis on the converging process for the configuration of the S1 and S2 stream filaments. The three–dimensional flow fields obtained in the quasi– and full 3D solutions are quite similar, but the former gives a lower peak Mach number and a smaller circumferential variation in Mach number than the latter. A comparison between the theoretical solution and the Laser–2–Focus measurement shows that the character of the transonic flow including the 3D shock structure is in good agreement, but the measured velocity is slightly higher than the calculated one over most of the flow field.
The Calculation of Three Dimensional Viscous Flow Through Multistage Turbomachines
Authors: Denton J. D.
Published: March 2015

The extension of a well established three dimensional flow calculation method to calculate the flow through multiple turbomachinery blade rows is described in this paper. To avoid calculating the unsteady flow, which is inherent in any machine containing both rotating and stationary blade rows, a mixing process is modelled at a calculating station between adjacent blade rows. The effects of this mixing on the flow within the blade rows may be minimised by using extrapolated boundary conditions at the mixing plane.
Local Heat Transfer in Turbine Disk-Cavities: Part II — Rotor Cooling With Radial Location Injection of Coolant
Authors: Bunker R. S. , Metzger D. E. , Wittig S.
Published: March 2015

Detailed radial distributions of rotor heat transfer coefficients are presented for three basic disk-cavity geometries applicable to gas turbines. The experimental apparatus has been designed to obtain local heat transfer data on a number of easily interchangeable rotor surfaces. The method employs thin thermochromic liquid crystal coatings upon the rotor surfaces together with video system data acquisition and computer-assisted image analysis to detect surface color display and to extract heat transfer information. A thermally transient, aerodynamically steady technique is used which attains consistent thermal boundary conditions over the entire disk-cavity. Cooling air is introduced into the disk-cavity via a single circular jet mounted perpendicularly into the stator at one of three radial locations; 0.4, 0.6 or 0.8 times the rotor radius. Rotor heat transfer coefficients have been obtained over a range of parameters including disk rotational Reynolds numbers of 2 to 5 · 105, rotor/stator hub spacing-to-disk radius ratios of .025 to .15, and jet mass flow rates between .10 and .40 times the turbulent pumped flow rate of a free disk. The rotor surfaces include a parallel rotor-stator system, a rotor with 5 percent diverging taper, and a similarly tapered rotor with a rim sealing lip at its extreme radius. Results are presented showing the effects of the parallel rotor, which indicate strong variations in local Nusselt numbers for all but rotational speed. These results are compared to associated hub injection data of Part I of this study, demonstrating that overall rotor heat transfer is optimized by either hub injection or radial location injection of coolant dependent upon the configuration. Results with the use of the tapered rotor show significant local Nusselt number radial variation changes over those of the parallel rotor, while the addition of a rim sealing lip appears to increase the level of the radial distribution.
Status of Topping Combustor Development for Second Generation Fluidized Bed Combined Cycles
Authors: Garland Richard V. , Pillsbury Paul W.
Published: March 2015

Addition of a fluidized bed combustor to a high efficiency combined cycle plant enables direct firing of inexpensive run-of-the-mine coal in an environmentally acceptable manner. To attain high thermal efficiencies, coal pyrolysis is included. The low heating value fuel gas from the pyrolizer is burned in a topping combustion system that boosts gas turbine inlet temperature to state of the art while the pyrolizer-produced char is burned in the bed.

The candidate topping combustor, the multi-annular swirl burner, based on a design by J. M. Beér is presented and discussed. Design requirements differ from conventional gas turbine combustors. The use of hot, vitiated air for cooling and combustion, and the use of low heating value fuel containing ammonia are two factors that make the design requirements unique.

The multi-annular swirl burner contains rich-burn, quick-quench, and lean-burn zones formed aerodynamically rather than the physically separate volumes found in other rich-lean combustors.

Although fuel is injected through a centrally located nozzle, the combustion air enters axially through a series of swirlers. Wall temperatures are controlled by relatively thick layers of air entering through the various swirler sections, which allows the combustor to be of all-metal construction rather than the ceramic often used in rich-lean concepts.

This 12-inch diameter design utilizes some of the features of the previous 5-inch and 10-inch versions of the multi-annular swirl burner; and, test results from the previous projects were utilized in the formulation of the test for the present program. In the upcoming tests, vitiated air will be provided to simulate a pressurized fluidized bed effluent. Hot syngas seeded with ammonia will be used to simulate the low BTU gas produced in the pyrolizer.
Influence of a Shroud on Swirler Flow Fields
Authors: Eroglu Hasan , Chigier Norman
Published: March 2015

The flow fields for swirlers with and without a shroud were measured using a two-component Laser Doppler Velocimeter (LDV) system. The primary goal of this study is to investigate the effect of shrouds on swirler flow fields, in order to provide useful design information for the manufacture of gas turbine fuel nozzles, and to supply benchmark data for comparison with numerical predictions. As a result of the measurements, the radial distributions of three mean velocity components, turbulence intensity, and shear stresses were obtained at five locations (x/d = 0.1, 1, 2, 4 and 8) along the axis of the swirlers. The LDV system was operated in the 20° off-axis forward scatter mode with beam expanders and Bragg cell frequency shifting on both components. The flow was seeded by 1 μm mean diameter atomized particles of glycerol and water (50/50) mixture. Comparison of flow with and without the shroud showed that the jet diameter was much smaller, and the flow deceleration in the downstream direction was faster, due to the influence of the shroud, at the same supply pressure (750 mm H2O). As a result of the significant reduction in the swirl number due to the addition of the shroud, the recirculation zone disappeared. In addition to its influence on recirculation, the shroud caused a radially inward shift of the maximum mean and turbulence parameters at all axial locations. The anisotropy of turbulence increased as compared to the values for the swirler without the shroud.
Mixing in Axial Flow Compressors: Part I — Test Facilities and Measurements in a Four-Stage Compressor
Authors: Li Y. S. , Cumpsty N. A.
Published: March 2015

The mechanism of mixing in axial flow compressors has been investigated in two low speed machines. For reasons of length this is described in two parts. Results in a 4-stage compressor are described here in Part I and show that the mixing coefficients across the first and the third stators are of similar magnitude. Part I also describes the background and experimental facilities and techniques used in both parts together with the nomenclature and all the references. Part II describes the results from a large single stage compressor. It also presents measurements of mixing in a simple two-dimensional duct, and presents conclusions for the whole investigation.
Navier-Stokes Analysis of Turbine Blade Heat Transfer
Authors: Boyle R. J.
Published: March 2015

Comparisons with experimental heat transfer and surface pressures were made for seven turbine vane and blade geometries using a quasi-three-dimensional thin-layer Navier-Stokes analysis. Comparisons are made for cases with both separated and unseparated flow over a range of Reynolds numbers and freestream turbulence intensities. The analysis used a modified Baldwin-Lomax turbulent eddy viscosity model. Modifications were made to account for the effects of: 1) freestream turbulence on both transition and leading edge heat transfer; 2) strong favorable pressure gradients on re-laminarization; and 3) variable turbulent Prandtl number on heat transfer. In addition, the effect on heat transfer of the near-wall model of Deissler is compared with the Van Driest model.
The Influence of Blade Lean on Turbine Losses
Authors: Harrison S.
Published: March 2015

Three linear cascades of highly loaded, low aspect ratio turbine blades have been tested in order to investigate the mechanisms by which blade lean (dihedral) influences loss generation. The blades in all three cascades have the same section but they are stacked perpendicular to the endwall in the first cascade, on a straight line inclined at 20° from perpendicular in the second and on a circular arc inclined at 30° from perpendicular at each end in the third cascade.

Lean has a marked effect upon blade loading, on the distribution of loss generation and on the state of boundary layers on the blade suction surfaces and the endwalls, but its effect upon overall loss coefficient was found to be minimal. It was found, however, that compound lean reduced the downstream mixing losses, and reasons for this are proposed. Compound lean also has the beneficial effect of substantially reducing spanwise variations of mean exit flow angle. In a turbine this would be likely to reduce losses in the downstream bladerow as well as making matching easier and improving off-design performance.
Three-Dimensional Flow in an Axial Turbine: Part 1 — Aerodynamic Mechanisms
Authors: Joslyn David , Dring Robert
Published: March 2015

This paper presents an exhaustive experimental documentation of the three–dimensional nature of the flow in a one–and–one–half stage axial turbine. The intent was to examine the flow within, and downstream of, both the stator and rotor airfoil rows so as to delineate the dominant physical mechanisms. Part 1 of this paper presents the aerodynamic results including: (1) airfoil and endwall surface flow visualization, (2) fullspan airfoil pressure distributions, and (3) radial–circumferential distributions of the total and static pressures, and of the yaw and pitch angles in the flow. Part 2 of the paper presents results describing the mixing, or attenuation, of a simulated spanwise inlet temperature profile as it passed through the turbine. Although the flow in each airfoil row possessed a degree of three–dimensionality, that in the rotor was the strongest.
Recent Test Results in the Direct Coal-Fired 80 MW Combustion Turbine Program
Authors: Bannister R. L. , Pillsbury P. W. , Diehl R. C. , Loftus P. J.
Published: March 2015

Under sponsorship of the Morgantown Energy Technology Center of the Department of Energy, the Westinghouse Electric Corporation and Avco Research Laboratory/Textron (ARL) are developing a direct coal-fired 80-MW combustion turbine. This is to be an element in a 207-MW direct coal-fired combustion turbine combined cycle, comprising another combustion turbine, a heat-recovery steam generator, and a steam turbine. Following conceptual and economic studies, the first experimental task has been to develop a direct coal-fired slagging combustor in small scale. A year’s testing with this unit has now been accomplished. It is thus possible to discuss experimental results in the areas of slag management, general combustor operability, coal fuel feed, heat loss, pressure loss, combustion efficiency, and emissions.

Westinghouse and ARL selected the slagging combustor for use in this program because of its unique ability to accept inexpensive standard utility-type coal without sending excessive pollutants and particulates to the expander-turbine. It accomplishes this by burning the coal at a temperature high enough to melt the ash, and then removing the molten slag with an impact separator. This combustor is also of the rich-lean type, which allows it to emit very low levels of NOx. Sulfur oxides are controlled through injection of a sorbent which combines with gaseous forms of sulfur in the rich zone, and then takes them out with the slag.

The plan in this program is to develop the slagging combustor in small scale at 12 million Btu/h (12.66 million kJ/h) heat input, 6 atmospheres pressure, and then move to design and verification testing of a full-scale 70 million Btu/h (73.85 million kJ/h), 14-atmosphere unit. It is with the smaller burner that this paper is concerned. During this period, coals have been fed into the 6-atm combustor exclusively in the dry-pulverized form with air as the carrier gas. To date, high- and low-sulfur eastern bituminous, and low-sulfur western subbituminous coals have been evaluated, with, and without sorbents, which have included various calcium and iron containing minerals. Coal samples have been of the 200 mesh size, and have not been beneficiated.

Combustor operation has been efficient and repeatable and slag flow has been symmetrical and manageable. Slag removal has been greater than 90 percent and carbon burnout has been greater than 99 percent. Nitrogen oxide emissions meet the goals of EPA’s NSPS for coal-fired plants. Current tests are focused on the goal of 90 percent sulfur removal. Although some results are available, various sorbents and injection techniques continue under test.
An Analysis of the Viscous Flow Through a Compact Radial Turbine by the Average Passage Approach
Authors: Heidmann James D. , Beach Timothy A.
Published: March 2015

A steady, three-dimensional viscous “average passage” computer code is used to analyze the flow through a compact radial turbine rotor. The code models the flow as spatially periodic from blade passage to blade passage. Results from the code using varying computational models are compared with each other and with experimental data. These results include blade surface velocities and pressures, exit vorticity and entropy contour plots, shroud pressures, and spanwise exit total temperature, total pressure, and swirl distributions. The three computational models used are inviscid, viscous with no blade clearance, and viscous with blade clearance. It is found that modeling viscous effects improves correlation with experimental data, while modeling hub and tip clearances further improves some comparisons. Experimental results such as a local maximum of exit swirl, reduced exit total pressures at the walls, and exit total temperature magnitudes are explained by interpretation of the flow physics and computed secondary flows. Trends in the computed blade loading diagrams are similarly explained.
Design Methodology for Splittered Axial Compressor Rotors
Authors: Tzuoo K.-L. , Hingorani S. S. , Sehra A. K.
Published: March 2015

Recent trend toward lightweight, compact compression systems for advanced aircraft gas turbine engines has created a need for very high pressure ratio fan and compressor stages. One way of achieving pressure ratio in excess of 3:1 in an axial blade row is to introduce splitters (partial vanes) between the principal blades, a concept pioneered by Wennerstrom during early 70s for application in a 3:1 pressure ratio single axial stage. This paper presents an advanced methodology for high pressure ratio splittered rotor design. The methodology centers around combining a meridional flow calculation, an arbitrary meanline blade generation procedure, and 3-D inviscid and viscous analyses. Methods for specifying work distribution, solidity, loss, and deviation distributions, as well as the airfoil generation and splitter vane placement are discussed in detail. Importance of 3-D viscous effects along with results from a 3-D viscous calculation for Wennerstrom’s splittered rotor are also presented.
Three-Dimensional Prescribed Velocity Blade Row Design
Authors: Molnar V. , Ridzon F. , Adame V.
Published: March 2015

A method for 3D turbomachine blade row design is presented as a subsequent tasks loop. The design follows the concept of the S1 and S2 streamsurfaces. A set of S1 surfaces is used for blade profile modification and a S2 mid-surface is used for hub and casing flow surface modification. A difference between target and actual flow velocity distribution is used to control iteration procedures for succesive geometry changes of an initial (original) blade row geometry. The design subroutines are added to standard direct codes. Results for several design cases are presented and discussed.
Combustion System Performance of a Water Injected MS7001E Gas Turbine Operating at a NOx Emission Level of 25 PPMVD
Authors: Fitts David O. , Symonds Richard A. , Western Edmond R.
Published: March 2015

This paper presents the results of emissions testing and combustion system dynamics testing of a “Quiet Combustor” equipped MS7001E gas turbine at the Midway Sunset Cogeneration Company in Fellows, California. Water injection is used to control NOx emissions to 25 ppmvd without selective catalytic reduction. Test results include NOx, CO, unburned hydrocarbons, VOC, and formaldehyde emissions levels, and combustor dynamic pressure levels. Combustion system hardware mechanical performance is described following the initial combustion system inspection.
Development of a New 25MW High Efficiency Heavy-Duty Gas Turbine H-25
Authors: Urushidani Haruo , Sasada Tetsuo , Wada Masamichi , Kawaike Kazuhiko
Published: March 2015

A new 25MW class gas turbine H-25 has been developed to meet both 50 Hz and 60 Hz power generation needs with high reliability and efficient performance utilizing advanced high temperature gas turbine technologies. Because of its superior performance, over 32% in simple cycle efficiency, the H-25 gas turbine enables significant reduction of fuel consumption compared with previous 25MH class turbines. The H-25 also achieves higher thermal efficiency in a combined cycle power plant and a cogeneration plant with a waste heat recovery boiler. The first unit entered commercial operation at the end of November 1988 after full load factory test instrumented with more than 800 pieces of instrumentation.

This paper describes the design features and the latest technological refinements in each component of the H-25 gas turbine. Also presented are the component test programs and the results of full load factory test and field test on the first unit.
The Turbine Regime of a Rear Axial Compressor Stage
Authors: Cyrus Václav
Published: March 2015

A detailed investigation of three-dimensional flow has been carried out in a low speed rear axial compressor stage with aspect ratio of 1 at the extreme off-design condition-turbine regime. Measurements were performed by means of both stationery and rotating pressure probes. The mechanism of flow in the rotor and stator blade row in the turbine regime is analysed. Comparison is made with flow mechanism at the design condition.
LDV Measurements of Turbulent Stresses in Radial Turbine Guide Vanes
Authors: Eroglu Hasan , Tabakoff Widen
Published: March 2015

The results of Laser Doppler Velocimetry (LDV) measurements, in particular, turbulent stresses in radial turbine guide vanes are presented in this paper, in order to provide experimental data for the numerical predictions. The flow velocities were measured at upstream, inside and downstream of the guide vanes for two different mass flow rates (0.2 lb/s “0.0907 kg/s” and 0.3 lb/s “0.1361 kg/s”) using a two-component LDV system. The results are presented as contour plots of turbulent stresses. The LDV system consists of a 5 watt argon-ion laser, the seeding particle atomizer, the optical and the data acquisition systems. The optical components were arranged in the backward scatter mode to measure two orthogonal velocity components simultaneously. Frequency shifts were used on both components to determine the flow direction. The results indicate a significant transport of higher turbulence fluid into the suction surface-end wall corner by the end wall cross flows inside the passage. High turbulent stress gradients show that there is considerable flow mixing downstream of the flow passages. Turbulence was found to be locally anisotropic everywhere.
Parametric Experiments on Coaxial Airblast Jet Atomization
Authors: Farago Zoltan , Chigier Norman
Published: March 2015

Experiments using high speed, high magnification, and high contrast photography on airblast coaxial atomizers were carried out to study the wave characteristics of liquid surfaces, ligament breakup, and droplet formation. Liquid flow rate was changed from 4 to 50 kg/h, corresponding to a velocity range of 1.5 to 18 m/s, and a Reynolds number range of 1400 to 18000. Air flow rate was varied from 8 to 70 kg/h, corresponding to a velocity range of 22 to 180 m/s, and a Reynolds number range of 13000 to 105000. Tube wall thicknesses of 145 and 320 microns were used.

Under different flow conditions, different jet instabilities (capillary, helical and Kelvin-Helmholtz) and different dominant mechanisms of ligament formation were observed. One of the most surprising experimental results is that, under certain flow conditions, the coaxial round liquid jet, surrounded by an axisymmetric annular air stream, forms a flat curling liquid sheet. This liquid sheet breaks into droplet clouds with a frequency of a few thousand Hertz and emits strong oscillations and fluctuating, highly non-axisymmetric vibrations.
Experimental Studies of Reactive and Non-Reactive Flows in Dump Combustors
Authors: Nejad A. S. , Ahmed S. A. , Roe L. A. , Gabruk R. S.
Published: March 2015

The objectives of this experimental program are two fold; first, to investigate, understand, and document the effects of heat release on the characteristics of a dump combustor flowfield; secondly, to provide a benchmark set of experimental data to aid the development of time averaged CFD codes. A limited number of velocity profiles are reported in this manuscript to illustrate the effects of combustion and heat release, at an equivalence ratio of 0.65, on dump combustor flows. High-speed photography and spectral analysis complemented velocity measurements and served to examine and characterize combustion instability limits. Results indicate that combustion altered the dump combustor flowfield and significantly reduced the length of the corner recirculation region.
An Analysis of Pressure Swirl and Pure Airblast Atomization
Authors: Mao Chien-Pei , Chuech S. G. , Przekwas A. J.
Published: March 2015

The present investigation examines the fundamental aspects of airblast atomization in both the breakup and drop dispersion regimes. Experiments were conducted using a high-magnification 4×5 camera and a Phase/Doppler particle analyzer to evaluate the spray characteristics and atomizer performance. The primary parameters of interest are: liquid film breakup length, spray angle, drop size and trajectory. Observation of wave formation and propagation along the sheet surface was made to provide guidance in formulating mathematical models. Effects of air flow and nozzle design on atomization were examined for a wide range of flow conditions.

Computational analysis was also utilized to predict the sheet breakup and subsequent drop behavior. This model considered a swirling sheet interacting with the surrounding air streams. The governing equations were formulated in a curvilinear coordinate system conforming to the film boundaries. Primary breakup is based upon linear stability analysis. The present model is capable of predicting the variations in thickness, trajectory, velocity, and angle of a liquid film as a function of nozzle geometry, operating conditions, fluid properties, and ambient conditions. Secondary breakup and drop history calculations were also included in the model to provide local drop size spectra.

Agreement between the experimental and predicted breakup length and angle was excellent. The predictions of drop size, trajectory and other parameters were qualitatively correct. The present investigation demonstrated a realistic approach for simulating the breakup process and described the physical structure of a pure airblast atomizer spray.
Evaluation of a Catalytic Combustor in a Gas Turbine-Generator Unit
Authors: Kajita Shinichi , Tanaka Yasutaroh , Kitajima Junichi
Published: March 2015

As a final step of the Catalytic Combustor Development Program, a catalytic combustor developed was tested in a 150-kW gas turbine-generator unit. A digital control system was developed to improve its controllability for a transient operation, and a 200-hr continuous operation test was performed to asses the durability of the catalyst. During the test, an excellent performance of the control system was verified, and a very high combustion efficiency of more than 99% and a ultra-low NOx level of less than 5.6 ppm (at 15% O2) were achieved at a 150-kW generator output. In addition, the combustion efficiency has been maintained at over 98% for 200 hours of operation. However, the catalyst exposed to 200 hours of operation showed signs of deactivation.
The Effect of a Turbulent Wake on the Stagnation Point: Part I — Skin Friction Results
Authors: Wilson Dennis E. , Hanford Anthony J.
Published: March 2015

The response of a boundary layer in the stagnation region of a two-dimensional body to fluctuations in the freestream is examined. The analysis is restricted to laminar incompressible flow. The assumed form of the velocity distribution at the edge of the boundary layer represents both a pulsation of the incoming flow, and an oscillation of the stagnation point streamline. Both features are essential in accurately representing the effect which freestream spatial and temporal nonuniformities have upon the unsteady boundary layer. Finally, a simple model is proposed which relates the characteristic parameters in a turbulent wake to the unsteady boundary-layer edge velocity. Numerical results are presented for both an arbitrary two-dimensional geometry and a circular cylinder.
Concave-Wall Laminar Heat Transfer and Görtler Vortex Structure: Effects of Pre-Curvature Boundary Layer and Favourable Pressure Gradients
Authors: Crane R. I. , Umur H.
Published: March 2015

The mean velocity field in the boundary layer and the streamwise and spanwise distributions of heat transfer coefficient have been measured on a concave wall in the presence of naturally-generated Görtler vortices, with and without a preceding flat wall. In near-zero pressure gradient, enhancement of the streamwise-averaged heat transfer above flat surface levels was associated with the attainment of a Görtler number of around ten, as found in previous experiments in a different flow facility with higher wall curvature, but occurred before the onset of severe distortion in the velocity profiles. Velocity gradient parameters K of 0·20 × 10−6 and 0·75 × 10−6 resulted in a more regular vortex structure, with spanwise averaged heat transfer reaching two to three times predicted levels. At K = 1·8 × 10−6, vortex amplification was suppressed to such an extent that no significant heat transfer enhancement took place. Comparison of measured Stanton numbers with those derived from skin friction factors (obtained from velocity profiles) suggested that the heat transfer enhancement is not simply a result of fuller velocity profiles in vortex downwash regions.
Testing of Ceramic Components in the Daimler-Benz Research Gas Turbine PWT 110
Authors: Stute M. , Burger H. , Griguscheit M. , Holder E. , Mörgenthaler K. D. , Neubrand F. , Radloff M.
Published: March 2015

The Daimler-Benz “Car 2000” research project included a two-shaft gas turbine which was used at speeds of up to 61,500 rpm and at temperatures of up to 1,250 °C (1st phase). Several ceramic components were pre-tested and used in the turbine engine both on the test bench and in the vehicle. The turbine engine has now reached a cumulative operating time of 600 hours; this includes 20,000 km on the road. Tested were HPSN components and other ceramic components which were manufactured in processes suitable for volume production. Some components have been tested on component test benches at temperatures of up to 1,350 °C. In the vehicle, temperatures of up to 1,350 °C were briefly encountered during acceleration.
Reliability Analysis of Ceramics Using the CERAM Computer Program
Authors: Lamon J.
Published: March 2015

The CERAM computer program for the structural reliability analysis of ceramic parts is presented. CERAM is based upon the Weibull’s model and the more fundamental Multiaxial Elemental Strength Model placing emphasis upon the microstructural defects. Then, the analysis of thermal shocks failure for alumina disks provides an example of failure predictions using CERAM.
Field Evaluation of On-Line Compressor Cleaning in Heavy Duty Industrial Gas Turbines
Authors: Haub Gary L. , Hauhe William E.
Published: March 2015

On-line compressor cleaning of heavy duty gas turbines in industrial cogeneration service has proven to be a cost effective method of reducing the rate of performance loss associated with compressor fouling. By selecting an injection system, and by varying the dosage, frequency, and cleaning products used, an optimum cost effective method can be achieved. This paper evaluates the online compressor cleaning system at two 300 Mw cogeneration plants (8 gas turbines) that have been using this system since 1986.
Effect of Particle Size Distribution on Particle Dynamics and Blade Erosion in Axial Flow Turbines
Authors: Tabakoff W. , Hamed A. , Metwally M.
Published: March 2015

This work presents the results of an investigation conducted to study the effect of coal ash particles size distribution on the particle dynamics, and the resulting blade erosion in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three dimensional trajectory analysis within the turbine blade passages. The particle rebound conditions and the blade material erosion characteristics are simulated using empirical equations, derived from experimental measurements. For the typical ash particle size distribution considered in this investigation, the results demonstrate that the size distribution has a significant influence on the blade erosion intensity and pattern.
Integrity Assessments of Components in the Creep Range
Authors: Penny R. K. , Weber M. A.
Published: March 2015

Robust methods for the predictions of deformations and lifetimes of components operating in the creep range are presented. The ingredients used for this are well-tried numerical techniques, combined with the concepts of continuum damage and so-called reference stresses. The methods described are derived in order to obtain the maximum benefit during the early stages of design where broad assessments of the influences of material choice, loadings and geometry need to be made quickly and with economical use of computers. It is also intended that the same methods will be of value during operation if estimates of damage or if exercises in life extension are required.

Results of the suggested method are amenable to tabular or graphical representation and to illustrate the use of these in parametric studies, three brief case studies are included. These involve a notched rod, a perforated plate, and a pipe for which life time estimates based upon failure criteria involving different degrees of conservatism are calculated. In addition, an illustration is given of the use of the charts presented in deciding inspection intervals and lifetime extensions. Finally, a brief excursion into the possibility for using the suggested methods for the mapping of designs within given regional constraints is given.
Analytical and Experimental Simulation of Fan Blade Behaviour and Damage Under Bird Impact
Authors: Teichman H. C. , Tadros R. N.
Published: March 2015

An extensive analytical and experimental program has been undertaken to investigate the Foreign Object Damage resistance capabilities of external components for small gas turbofan engines. A transient nonlinear impact analysis has been used to predict the structural response of fan blades under bird ingestion conditions. This analysis is based on finite elements, a 3-D bird load model and an interactive structure-to-bird contact algorithm. Experiments were designed and carried out to record large blade deformations during bird impact, and were used to validate and calibrate the analytical models. The analytical models and testing program are described, and dominant fan blade response and failure modes are presented. Predicted results demonstrate good correlation with test. Analysis application to fan blade design and other engine components is recommended.
Tip Leakage Flow in Axial Compressors
Authors: Storer J. A. , Cumpsty N. A.
Published: March 2015

Experimental measurements in a linear cascade with tip clearance are complemented by numerical solutions of the three-dimensional Navier-Stokes equations in an investigation of tip leakage flow. Measurements reveal that the clearance flow, which separates near the entry of the tip gap, remains unattached for the majority of the blade chord when the tip clearance is similar to that typical of a machine. The numerical predictions of leakage flow rate agree very well with measurements and detailed comparisons show that the mechanism of tip leakage is primarily inviscid. It is demonstrated by simple calculation that it is the static pressure field near the end of the blade which controls chordwise distribution of the flow across the tip. Although the presence of a vortex caused by the roll-up of the leakage flow may affect the local pressure field, the overall magnitude of the tip leakage flow remains strongly related to the aerodynamic loading of the blades.
The Effects of Wake Mixing on Compressor Aerodynamics
Authors: Dring Robert P. , Spear David A.
Published: March 2015

A methodology based on wake mixing has been developed that enables more accurate predictions of compressor airfoil pressure distributions when the airfoil is operating downstream of an airfoil row that has strong wakes. The methodology has an impact on through–flow analysis, on airfoil–to–airfoil flow analysis, and on the interpretation of experimental data. It is demonstrated that the flow in the endwall region is particularly sensitive to mixing due to the strong wakes caused by the secondary flow and corner separation that commonly occur in this region. It is also demonstrated that wake mixing can have a strong impact on both airfoil incidence and deviation as well as on loading. Differences of up to 13° and 30% in loading are demonstrated.
Pressure Losses in Combining Subsonic Flows Through Branched Ducts
Authors: Abou-Haidar N. I. , Dixon S. L.
Published: March 2015

An investigation of the “additional” total pressure losses occurring in combining flow through several sharp-edged three-leg junctions has been made. Experimental results covering a wide speed range up to choking are presented for three flow geometries of a lateral branch off a straight duct using dry air as the working fluid. A new theoretical flow model provided results in fairly good agreement with the experimental data obtained. Flow visualisation of the high speed flow using the Schlieren method revealed the presence of normal shock waves in the combined flow about one duct diameter downstream of the junction. The highest attainable Mach number (M3) of the averaged downstream (combined) flow was 0.66 for several of the flow geometries. This value of M3 appears to be the maximum possible and is the result of a combination of flow separation and local flow choking.
Cogenerative, Direct Exhaust Integration of Gas Turbines in Ethylene Production
Authors: Cooke David H. , Parizot William D.
Published: March 2015

Within the past few years, gas turbines have been integrated in several new world-class ethylene production plants, for the first time using the exhaust as a source of preheated combustible oxygen for the cracking furnaces. The economic inducements and technical impact of such integration on the process are discussed. The general ethylene cracking and recovery process is described, and the various ways of integrating gas turbines are compared, culminating in the current leading designs. Means of providing ambient air backup to protect furnace operation from gas turbine trips are discussed. Furnace group sizing and oxygen demand for the major feedstocks, including naphtha and ethane/propane, are compared with the current range of oxygen and power available from single and dual gas turbines on the world market. Methods of partial integration, where gas turbine integration of the entire ethylene plant would produce more power than can be economically utilized or consume more premium fuel than available, are discussed. Fuel savings relative to ambient air operation are parametrized with percent exhaust oxygen and exhaust temperature. Aeroderivative and industrial gas turbine types are compared. Comparative economics with another means of gas turbine cogeneration, that of auxiliary boiler replacement with a combined cycle in a central utility, are presented.
Design and Testing of a Controlled Diffusion Airfoil Cascade for Industrial Axial Flow Compressor Application
Authors: Steinert W. , Eisenberg B. , Starken H.
Published: March 2015

Similarly as in jet engine development, modern design methods are used today to improve the performance of industrial compressors. In order to verify the loading limits, a cascade profile representative for the first rotor hub section of an industrial compressor has been designed by optimizing the suction surface velocity distribution using a direct boundary layer calculation method. The blade shape was computed with an inverse full potential code and the resulting cascade was tested in a cascade windtunnel. The experimental results confirmed the design intent and resulted in a low loss coefficient of 1.8% at design condition and an incidence range of nearly 12° (4% loss level) at an inlet Mach number of 0.62.
Industrial RB211: 15 Years of History and Development
Authors: Soinne P. E. , Stephens R. J.
Published: March 2015

The Industrial RB211 was derived from the aero RB211-22B engine in the early 1970’s and was first installed at Burstall, Canada in 1974 as a prime mover in the Trans Canada Pipe Lines gas transmission pipeline.
The Development of Axial Turbine Leakage Loss for Two Profiled Tip Geometries Using Linear Cascade Data
Authors: Bindon Jeffrey P. , Morphis George
Published: March 2015

To assess the possibility of tip clearance loss reduction and to explore the nature and origin of tip clearance loss, blade tip geometries which reduce the roughly 40% of total loss occurring within the gap were studied. The shapes investigated aimed at reducing or avoiding the gap separation bubble thought to contribute significantly to both internal gap loss and to the endwall mixing loss. It was found that radiusing and contouring the blade at gap inlet eliminated the separation bubble and reduced the internal gap loss but created a higher mixing loss to give almost unchanged overall loss coefficients when compared with the simple sharp edged flat tipped blade. The separation bubble does not therefore appear to influence the mixing loss. Using a method of assessing linear cascade experimental data as though it were a rotor with work transfer, one radiused geometry, contoured to shed radial flow into the gap and reduce the leakage mass flow, was found to have a significantly higher efficiency. This demonstrates the effectiveness of the data analysis method and that cascade loss coefficient alone or gap discharge coefficient cannot be used to accurately evaluate tip clearance performance. Contouring may ultimately lead to better rotor blade performances.
Flexibility and Adaptability of Closed Brayton Cycles Associated With Low Power Level Space Nuclear Heat Sources
Authors: Tilliette Z. P. , Carre F. O. , Proust E.
Published: March 2015

A feature of the French preliminary studies of space nuclear power systems of about 20 kwe is the selection of the closed Brayton cycle as the conversion subsystem.

As examples of future applications of turbogenerators in space, near or longer term U.S. and Soviet projects are mentioned, including technical advances expected in this field.

Several nuclear reactors concepts can be proposed now or in the future. The need for a satisfactory adaptation between the heat source and the converter prompts to further investigate the Brayton cycle capability for that purpose. For instance, a long lifetime thermal spectrum reactor would require a relatively low inlet temperature for moderator thermal conditioning. Cycle configurations featuring one or two separate radiators and possible intercooling are presented. Such arrangements imply a main low temperature radiator made, for instance, of multiple, pivoting tubes.

It is shown that the Brayton cycle can offer flexibility and adaptability for a wide range of space missions.
Coal Mineral Matter Transformation During Combustion and its Implications for Gas Turbine Blade Erosion
Authors: Rajan S. , Raghavan J. K.
Published: March 2015

The transformation of mineral matter during combustion and the characteristics of the ash formed are important from the standpoint of coal fired gas turbine operation. Using a novel FT-IR technique and EDX analysis, these mineral matter transformations are investigated when the coal is burnt in a one-dimensional pulverized coal-dust-air flame. The role of clays, pyrite, quartz, potassium and other compounds in the ash are discussed with particular reference to deposit buildup and erosion of gas turbine blades.
A GCC Power Plant With Methanol Storage for Intermediate-Load Duty
Authors: Paffenbarger John A.
Published: March 2015

This paper describes the design and performance of a coal gasification combined-cycle power plant with an integrated facility for producing and storing methanol (GCC/methanol power plant). The methanol is produced at a steady rate and is burned in the combined-cycle to generate additional power during periods of peak electrical demand. The GCC/methanol plant provides electricity generation and energy storage in one coal-based facility. It is of potential interest to electric utilities seeking to meet intermediate-load electrical demand on their systems.

The plant configuration is determined by means of an economic screening study considering capital and fuel costs over a range of cycling duties (load factors). Estimated levelized electricity production costs indicate that a GCC/methanol plant could be of economic interest as premium fuel prices increase relative to coal. The plant could potentially be of interest for meeting daily peak demands for periods of eight hours or less.

The conceptual plant configuration employs a Texaco gasifier and a Lurgi methanol synthesis plant. Plant performance is estimated at peak and baseload output levels. No unusual design or operational problems were identified.
Technical and Other Considerations for the Selection of Inlet Air Filtration Systems for High-Efficiency Industrial Combustion Turbines
Authors: Goulding Cecil H. , Rasmussen Myron G. , Fritz Frederick M.
Published: March 2015

Each combustion turbine installation has peculiar to it site-related characteristics that, if considered carefully, will define the type of inlet system that best fits the operational requirements. Historically, and unless owner specified, the OEM/Packager supplies his standard, all-purpose air filter configuration as an integral part of the package. The standard may or may not be the best selection for filtering combustion inlet air at the intended specific site location. This technical paper will match inlet air filtration systems to several typical ambient conditions, using laboratory tests and actual site experience. This paper can also be used as a technically current selection guide for those considering various inlet air filtration requirements for new and retrofit systems.
Improvements in Incinerators by Means of Gas Turbine Based Cogen Systems
Authors: Wiekmeijer Ir. Ted
Published: March 2015

In this paper a new process is described to improve the efficiency of power generation in waste incineration plants. It is proposed to superheat the steam in a gas turbine/waste heat boiler combination rather than in the incinerator boiler.

Although this is not discussed in this paper the same process may be applied in nuclear power stations where the superheating of steam is also a problem.

A global risk-analysis of the addition of equipment is made in this paper. On basis of a case-study the financial advantages are demonstrated.
A Contribution to Designing a Radial Flow Gas Turbine Stage
Authors: Bhinder F. S.
Published: March 2015

The performance of a radial inward flow gas turbine stage depends on the design of the rotor as well as that of the casing. The paper describes a simple procedure for designing the complete stage comprising a rotor and a single entry nozzle-less volute casing. The rotor design follows a prescribed mean stream velocity distribution in a step by step manner and the casing design uses the radial equilibrium together with the conservation of mass energy and momentum equations.
Control System Design: Gas Turbine Machinery: The Use of a Corporate Model for Control System Design
Authors: Girolami Silvio
Published: March 2015

This paper describes a systematic, consistent approach to control design developed over years of theoretical design and field testing. The Gas Turbine Generator Set control (with some Hover-craft Lift control variations) is discussed both as an example of the design method and as a project on its own merit.

This control ideology is not dependent on implementing hardware, high level languages. It is an organic method based on an example of “human” organization, the corporation. The Gas Turbine control is an interactive corporate team; member personalities and duties are the logic.

The rationalized I-T-E (if-then-else) method of defining and programming the control (corporate) personalities is used by the turbine and controls engineers to efficiently produce the final turbine and machinery control algorithms.

A simple integrated software/hardware scheme facilitates recording and executing these algorithms.

Last but not least, reliable control performance must be achieved through an inherently fail-safe “systems” approach.
New Generation of the Small Turboshaft and Turboprop Engines in the U.S.S.R.
Authors: Ponomariov Boris A.
Published: March 2015

The main requirements for a new generation of small turboshaft and turboprop engines in the USSR are considered. The main performance of the new small engines developed in the USSR are given and their features are emphasized.