bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Advanced Coal-Fired Gas Turbine Locomotives
Authors: Liddle Sidney G.
Published: April 2015

A study was made of 526 advanced coal-fired locomotive concepts of which 182 used gas turbine engines. This paper summarizes the results of the gas turbine portion of the study. Fifteen forms of coal including coal derived liquids, 15 different combustors, and five types of gas turbine engines were investigated. The principal means of comparing the different engines is by their life-cycle costs. The reason for this approach is that the greatest attraction of coal-fired locomotives is their low operating costs relative to that of Diesel-electric locomotives now in use. Many of the coal-fired locomotives have half the life-cycle costs of comparable Diesel-electrics. Although the analysis was made for conditions in the United States, the results are applicable to other countries.
Analysis for Thermal Elasto-Plasticity and Creep of Turbine Disks
Authors: Chang-Bing Shung , Zhi-Yong Peng
Published: April 2015

This paper analyzes the thermal elastic-plastic-creep at the bottom of slots in turbine disks using three-dimensional finite elements. Considering the low cycle of engine parts during takeoff-operating-landing process, the yield stress surface of the material is treated according to the kinematic hardening rule. Since the plastic strains are caused by transient loads when starting the engine, being time-independent, while the creep strains are caused by hold time and large loads under high temperature, being time-dependent, the calculation is performed for these two cases, respectively. This would be more correspondent to the practical states of engine. The computation results show that the creep of turbine disks is under neither constant stresses nor constant strains, but is under the combination of both. This phenomenon brings forward a new concept to predict the fatigue/creep life of turbine disks.
Evaluation of Gas Turbine/Compressor Control System Effectiveness Using Dynamic Simulation
Authors: Chui K. C. , Pobanz N. E. , Chang L. H.
Published: April 2015

In centrifugal compressor installations that use a variable speed drive such as gas turbine, speed control is an effective method of controlling capacity. Compressors are normally protected from surging by an antisurge control loop which recycles the discharged gas to the suction of the compressor. In an upset condition which results in flow reduction, the two controllers may interact whereby performance of the surge controller may be compromised. In this paper, a dynamic simulation technique is used to illustrate the interaction.
An Intercooled Regenerative Rolls-Royce Spey Gas Turbine
Authors: Thomas W. J. R. , Higson A. J.
Published: April 2015

This paper aims to describe very briefly the Rolls-Royce 18 MW SMIC marine Spey gas turbine, the development of which was dealt with in more detail in reference 1, and then to show how intercooling and regeneration could be added to increase its power to about 22 MW, with an associated increase in thermal efficiency to about 43%. As the SM1C based “ICR” unit is still very much in the infancy of its design, this paper does not discuss the design in detail; indeed, the details are certainly not all within the Rolls-Royce design sphere, as the Allison Gas Turbine Division of General Motors Corporation and Garrett AiResearch are partners of Rolls-Royce Limited and Rolls-Royce Inc. in the project. The broad principles of the improved cycle are described and then the effects of the use of such a unit on the operational characteristics of warships are discussed, comparing them with those of warships using simple cycle Spey SM1C units in different installation configurations. This paper stands on its own, but may also be regarded as the second part of reference 1.
VEGA Combined Cycle Power Plants
Authors: Lugand Paul , Boissenin Yves
Published: April 2015

A gas turbine is often associated with the steam cycle in the combined cycle electric power plants. Many plants of different combined cycle types are already in service, all distinguished by outstanding efficiency (45 to 47 %) and operating flexibility. We have thought it interesting to take stock of the steam and gas (VEGA) cycles especially destined for power plants. After outlining the thermodynamical optimization of the cycles, we shall develop the design and the practical realization of the combined cycle power plants.
Deposition, Erosion and Corrosion Protection for Coal-Fired Gas Turbines
Authors: Wenglarz Richard A.
Published: April 2015

Probably the greatest technical uncertainty for gas turbines directly fired with coal fuels is flowpath degradation due to deposition, erosion and corrosion from coal ash. Mechanisms of turbine deposition, erosion, and corrosion are discussed here and critical factors affecting these degradation processes are identified. Control of these factors is addressed as a basis for providing acceptable lifetimes of turbines operating with coal-derived and other ash bearing fuels.
Investigation of a Tip Clearance Cascade in a Water Analogy Rig
Authors: Graham J. A. H.
Published: April 2015

The tip clearance flow region of high pressure axial turbine blades for small gas turbine engines has been investigated in a water flow cascade. The blade model features variable clearance and variable endwall speeds. The cascade is scaled for Reynolds number and sized to give velocities suitable for visualization. Pressure profiles were measured on one blade, and correlated with the visualization. Unloading is found to be a major feature of the pressure field at both tip and midspan, and is intimately connected with scraping effects and the behavior of the clearance vortex. Some initial hot film velocity measurements are also presented.
The Properties of the Flow in an Elastic Duct
Authors: Wei You-Hai , Mao Xi-Chang , Fang Ren
Published: April 2015

The flow in an elastic duct has some special properties. The speed of sound in this kind of flow is discovered to be smaller than in the flow in a rigid duct. Since the speed of sound decreases, flows which include area change, friction, heat transfer and mass addition reach the critical condition at Mach number less than one (M=1). It is particularly interesting that in a flow with area change the critical section doesn’t coincide with the minimum section. The main property of the flow in an elastic duct, that is the speed of sound being smaller than the traditional one, has been proved by experiment.
The Finite Element Stress Analysis for Solid-Shell Combined Parts in Aeroengines
Authors: Zeyong Yin , Peizheng Ren , Jing Yin
Published: April 2015

In the finite element stress analysis of solid-shell combined parts in aeroengines, isoparametric solid elements, superparametric shell elements, solid-shell transition elements and a series of coarse-fine mesh transition elements have been specially established and used so that the parts of complex shape can be modeled realistically, and the amount of input data and computing time can be reduced.

In this paper, the basic method used, the formulation of the various elements and the solving of the equilibrium equations are presented, and the function and the structure of the general purpose program CACS are described.
Experimental Investigation on Aerodynamic Characteristics of a Variable Area Nozzleless Volute
Authors: Zhenping Feng , Zuda Shen , Yimin Xiang
Published: April 2015

The aerodynamic characteristics of a variable area nozzleless volute (VAV) for small radial inflow turbines are studied with the aid of cold air tests in which flow parameters inside the volute channel and at the outlet of the nozzleless ring are measured for cases of various cross-sectional areas. The experimental investigation shows that the desired aerodynamic parameters, especially the outlet flow angle α1 as well as the mass flow rate range can be obtained by varying the croes-sectional area of the VAV. A reasonable approximate method for calculating the average outlet flow angle α1 is presented in which the variation of the circulation in the flow is taken into account.
Measurement of Turbine Blade Temperature Using Pyrometer
Authors: Huilin Cheng , Chunxiang Du
Published: April 2015

This paper presents the study of application of a self-made turbine blade pyrometer to measuring rotating turbine blade temperatures in a bed testing aeroengine. The study includes the temperature measuring principle and the pyrometer system; Installation and adjustment of the double ball-floating type configuration optical head which goes through four different high temperature bulkheads; Measurement of three kinds of temperatures (the average blade temperature Ta, the average peak blade temperature Tap, and the maximum peak blade temperature Tmp) for all rotor blades of the turbine first stage. The experimental data analysis reveals that the first attempt of application of this pyrometer is successful. The measurement errors in the temperature range of 550–1200° C are within ±1% of calculated blade temperatures.
The Numerical Experiments of the Unsteady Aerodynamic for the High-Turning Oscillating Cascades
Authors: Yi Chen Zuo , Sheng Duan Qiu , Zhong Duan Shi
Published: April 2015

An “oscillating mean-streamline method” is presented in this paper. It is used to calculate the unsteady aerodynamic force on the oscillating high-turning cascade. An oscillating streamline physical model is discussed, basic relations of the oscillating streamline are derived, the calculations of several examples are given and are compared with corresponding experimental data.

The validity and reliability of this method is also analysed.
Investigating Complex Non-Reacting Flow Field in Combustor With a Two-Dimensional LDA
Authors: Qixun Lin , Yisheng Ding , Qinfang Du , Ming Tang , Ningfang Xiao
Published: April 2015

A vaporizing tube model combustor was constructed and the non-reacting flow field in it was measured by employing a two-dimensional Laser Doppler Anemometer (LDA) systerm. The complex flow pattern, including the recirculation zone, can be identified clearly. The turbulence distribution can also be obtained. Some experience with LDA application to combustor flow field measurement had been summed up. The measured results had been compared with those measured by a conventional two-dimensional pitot probe.
The Computer Aided Design and Experiment of the Transonic Turbine Cascade
Authors: Zhao Yuqi , Zhan Tingxiong , Xiao Hongen , Zheng Jianhui
Published: April 2015

This paper presents a method for the computer aided design of the transonic turbine blade profile shaping and aero thermodynamic analysis.

A new technique of “Computational Geometry” was developed for blade flow path shaping. An improved method of “Streamline Curvature” for cascade analysis is used for blade-to-blade stream surface analysis.

Using above method, a high-loaded turbine cascade with anti-convex suction surface near the trailing edge has been successfully designed, and appreciable supersonic performance was achieved through wind tunnel test.

This method has been included in our “Turbine Blade Computer Aided Design System (GTCAD)” as one of the core modules.
Modified Characteristic Method for Calculation of Supersonic S2 Flow Field in Compressor
Authors: Tao Bo , Ping-Cheng Shen
Published: April 2015

It is understood that the flow field calculation for the high-loaded super- or transonic compressor in inviscid gas model is essential in order to minimize the complexity of viscid calculation and, hereof the characteristic method has been often adopted for its relative effectiveness. However, due to the irregular grids and complex boundary conditions in turbomachines some difficulties still remain. This paper introduces a simpler and more practical characteristic method adopting reverse directional differentials for solving supersonic S2 flow field in supersonic or transonic compressors.
Calculation of External and Internal Transonic Flow Field of a Three-Dimensional S-Shaped Inlet
Authors: Huili Shen , Shijun Luo , Minggang Ji , Zongwen Xing , Xin Zhu , Xifeng Han
Published: April 2015

A mixed finite difference method for calculating the external and internal transonic flow field around an s-shaped inlet is presented. Starting from the velocity potential equation and using Cartesian mesh and mixed finite difference schemes, the authors have obtained a system of finite difference equations and solved them with the aid of alternating line relaxations along two directions. Computations have been made for an s-shaped inlet with free stream Mach number M=0.8 at different angles of attack. Computed results are compared with those computed by perturbation method and with experimental results. Such a comparison shows that the present method is promising.
A Jet Fuel Starter and Expendable Turbojet
Authors: Rodgers Colin
Published: April 2015

The small gas turbine jet fuel starter (JFS) and the expendable turbojet share common technology. Both designs are essentially constrained by high power density, low costs, and technology levels for small turbomachinery. Recognized early by the Air Force through the promotion of its expendable gasifier program, this common technology is now reaching fruition with initial development of the F-16 T-62 “Titan” JFS into a low cost turbojet. The relatively high production base for the T-62 Titan, which has more than 15,000 units of all models in service, plus a high degree of component commonality holds promising potential for realistic achievement of a low cost turbojet. Technical features of the Titan JFS and the turbojet are presented in this paper to demonstrate their common technology. Profitable technology avenues for improving power density and life cycle costs are discussed and recommendations made for development of higher performance levels.
A Theoretical Solution of Three-Dimensional Flows in Subsonic, Transonic and Supersonic Turbomachines: An Exact Solution and its Numerical Method
Authors: Miyazaki T. , Hirayama N.
Published: April 2015

A theoretical solution of a nonviscous flow through subsonic, transonic and supersonic arbitrary turbomachines is presented. The basic relations given by Wu are finally reduced to complex integral equations and then solved rigorously with pseudo-analytic function theories for boundary value problems and conformal mapping theorems which may simplify given flow fields. As the numerical method of the solution successive iteration is used. In the present paper only a schema of computational procedures of the three-dimensional flow is described. Moreover, detailed consideration on problems associated with Wu’s model is omitted. The numerical method is easy to accomplish in the whole flow regions, because numerical procedures are done mainly along the boundaries. Numerical examples given are limited to those for subsonic and shock free transonic flows.
Experimental Study of Three-Dimensional Flow in an Axial Compressor Stage
Authors: Cyrus Vaclav
Published: April 2015

A detailed investigation of three-dimensional flow was carried out in a low speed axial compressor stage with aspect ratio of 2. Data were obtained over a range of flow coefficient. The origin of large high loss regions in each blade row was found by means of a diffusion factor. The loss coefficient of rotor and stator blade rows was established on the basis of both rotating and stationary pressure probes. The predicted rotor and stator loss coefficient was compared with experiment.
Measurements of Mass Transfer Coefficient and Effectiveness in the Recovery Region of a Film-Cooled Surface
Authors: Webster W. P. , Yavuzkurt S.
Published: April 2015

Mass transfer coefficients and the film cooling effectiveness are measured downstream of a single row of holes inclined 30 degrees with the surface and inline with the main turbulent boundary layer flow. The mass transfer coefficients (based on the difference between the free stream and the surface concentrations) are measured using a naphthalene sublimation technique. The effectiveness is determined through the injection of a trace gas into the secondary (cooling jets) flow and measuring its concentration at the impermeable wall. Experiments are carried out in a subsonic, zero pressure gradient turbulent boundary layer, under isothermal conditions with three blowing ratios (Uj/U∞): 0.4, 0.8, and 1.2. The data is collected in a region 7 to 80 jet diameters downstream of the injection location.

From the data on mass transfer coefficients and effectiveness obtained under the same flow conditions a general mass transfer equation is derived. This paper presents extensive data and discussions; and is believed to be one of the few studies in which both of these variables are measured on the same surface and in a large area in the recovery region.
The Influences of Off-Design Incidence Angle and Discrete Hole Shapes on Film Cooling Effectiveness
Authors: Ko Shao-Yen , Liu Deng-Ying , Jia Jian-Guo , Tsou Fu-Kang
Published: April 2015

Detailed tests have been conducted in the cascade heat transfer wind tunnel in order to investigate film cooling effectiveness of single and double-row discrete holes on the leading edge of the pressure surface of a turbine blade. Mass transfer analogy has been used in this experiment. Carbon dioxide was added to the cooling air. The concentration distribution of the carbon dioxide downstream of the cooling film was measured by chromatograph.

Two sets of testing blades with discrete holes of different shapes were used. The first set had round holes with diameter of 1.5 mm, and the ejection angle was 70°. The second set had rectangular holes with width of 1.0 mm and whose ratio of length to width was 5, the ejection angle being 90°. The holes between rows were arranged in staggered pattern.

It was found that the incidence angle has strong influence on film cooling of turbine blades. The film cooling effectiveness near the ejection hole on the pressure surface (concave surface) is higher than that on a flat plate and on a suction surface (convex surface). Over a wide range of blowing ratio M, the film cooling effectiveness of rectangular hole is much higher than round holes.
ASME 1986 International Gas Turbine Conference Transpiration Cooling: Contribution of Film Cooling to the Overall Cooling Effectiveness
Authors: Andrews G. E. , Asere A. A. , Mkpadi M. C. , Tirmahi A.
Published: April 2015

Future gas turbine combustion chambers and turbine blades require better cooling techniques to cope with the continual rise in operating temperatures with each new engine model. One technique that has been extensively investigated is that of transpiration cooling, for both combustion chambers (1–5) and turbine blades (6–9). However, most porous metal materials used in transpiration cooling are not adequate for gas turbine long life operation. Consequently, there is a requirement for simple, stronger and more reliable cooling techniques. Two similar materials developed for engineering reliability and transpiration characteristics are Lamilloy developed by Detroit Diesel Allison (10,11) and Transply developed by Rolls Royce (12). These materials both have full coverage discrete inlet and outlet holes but with internal passages within the wall connecting the two holes. Special manufacturing facilities exist to produce the complex geometries with metal thickness similar to current aero engine practice. However, these materials are not commercially available, are made in a limited range of designs and have large temperature gradients which may affect their life (10,11).
Friction Damping in Compressor Blade Dovetail Attachments
Authors: Allen J. M.
Published: April 2015

An empirical model is presented for predicting the fundamental mode resonant response of friction damped, free standing compressor blades from the cyclic slip that can occur in its dovetail attachment. The model is an extension of the conventional approach in that it includes the microslip regime of slip by assuming that the tangential force coefficient (tangential force to normal force ratio when slip occurs) depends on the magnitude of slip but, like friction coefficient, is independent of normal force. Experimental data obtained from bench damping tests are presented relating these quantities for plain and coated [copper-nickel indium (Cu-Ni-In) plus molydisulphide (MoS2)] dovetail attachments. The results demonstrate that substantial friction damping can be obtained at low compressor speeds, where aerodynamic excitation is often most severe, and that such damping is dominated by the microslip properties of the dovetail interface. The dovetail coating significantly increased friction damping and proved to be durable in an endurance test, as it has in service.
The Allison 570/571 Gas Turbine for Patrol Boat Power
Authors: Roberts John E.
Published: April 2015

This paper discusses the use of 570/571-KF engine in patrol boat propulsion applications. The text is composed of two basic sections — 1. The Engine, and 2. The Applications:

The engine section includes a brief review of the background and development of this free turbine engine, as well as a description of the main components and design features. The performance characteristics and fuel consumption rates are discussed relative to patrol missions.

In the applications section a comparison is made of the current 570 installations (both civil and military), along with a survey of the planned applications. Finally a review of proposed uses of these engines in other naval vessels is included to show the adaptability of this size engine in FPB and PB missions, and demonstrate the feasibility of retrofitting other turbine or diesel powered patrol boats with 570/571-KF engines.

The conclusion is drawn that for patrol boats with conventional or modified hull forms, the Allison 570/571 engines are well suited due to their excellent performance and power density ratios.
The Performance of a Reverse Flow Combustor Using JP 10 Fuel
Authors: Winter J. , Maden K. H.
Published: April 2015

The test rig performance of a fan spray fuel injection reverse flow combustor for a 500 shp engine using JP 10 fuel is compared with that using aviation kerosene, (Avtur). JP 10 fuel is a pure hydrocarbon with a hydrogen content of 11.8% compared with some 13.8% for aviation kerosene.

The comparative performance data reported include fuel injector atomisation characteristics, exhaust combustion efficiencies and emmissions, exhaust temperature distributions, flame tube metal temperatures and simulated pressure altitude relight and combustion stability over a range of conditions up to a simulated altitude of 6,1 km.
Performance Characteristics of Two- and Three-Dimensional Impellers in Centrifugal Compressors
Authors: Harada H.
Published: April 2015

The overall performance of two- and three-dimensional impellers of a centrifugal compressor were tested and compared. A closed loop test stand with Freon gas as working fluid was employed for the experiments. The inlet and outlet velocity distribtions of all impellers were measured using three hole cobra probes. As a result, it has been revealed that three-dimensional impellers are superior to two-dimensional one in terms of efficiency, head coefficient and operating range. Further, it has also been clarified that the impeller slip factor is affected by blade angle distribution.
A Model for Bluff Body Flame Stabilization
Authors: De Champlain J. A. , Bardon M. F.
Published: April 2015

Previous work on bluff body stabilization mechanisms is reviewed, and existing models are categorized in tabular form, showing the underlying assumptions and resulting equations. Lacunae in existing models are discussed, particularly their reliance on characteristics such as laminar flame speed which is difficult to predict for the conditions encountered in turbojet afterburners.

A model for bluff body flame stabilization is proposed based on the stirred reactor approach. In addition to the effect of temperature, pressure and geometry, it includes chemical effects such as vitiation and fuel-air equivalence ratio. Blow off velocities predicted by the model are compared to experimental data for various conditions.
Premixing Gas and Air to Reduce NOx Emissions With Existing Proven Gas Turbine Combustion Chambers
Authors: Becker B. , Berenbrink P. , Brandner H.
Published: April 2015

In the case of the burners employed in KWU gas turbine combustion chambers, the entire primary air is supplied through the swirlers associated with the burners. It is thus relatively easy to add natural gas to this air uniformly before it enters the combustion zone. This results in a particularly low NOx combustion process provided that the air to fuel ratio is being maintained within a certain range. The supplementary equipment to premix the fuel and air does not affect the burner performance when the fuel is supplied in the conventional way by means of gas or oil nozzles. Consequently, the gas turbine will be started up and loaded in the usual manner. In the high load range the burners are then switched over to premixed combustion operation. A small amount of fuel through the central gas nozzle stabilizes the flame in the case of a sudden load decrease. Combustion chambers already in service can be retrofitted with the new premixing equipment to reduce NOx emissions to about one third of the original values. The combustors can be operated with liquid fuels together with steam or water for NOx reduction in the conventional way.
A Study on NOx Emissions From Gas Turbine Combustor
Authors: Sasaki Masafumi , Itoh Takane
Published: April 2015

A conventional diffusion-flame combustor and a two-stage combustor, both made of ceremics, were tested using various fuels.

In both combustors, CO, HC and smoke emission were extremely low even when using heavy-B fuel because of higher than normal inlet temperature of up to 1200 K; however, a great amount of NOx emission was observed in the conventional diffusion-flame combustor. When low-nitrogen fuels such as kerosene were used, a successful reduction of NOx was achieved by providing lean combustion in an improved diffusion-flame combustor. For high-nirogen fuels, the conversion fraction of fuel nitrogen to NOx could be minimized by keeping the equivalence ratio slightly rich in the first stage of the two-stage combustor.
Secondary Losses in a Large Deflection Annular Turbine Cascade: Effect of the Entry Boundary Layer Thickness
Authors: Govardhan M. , Venkatrayulu N. , Raj D. Prithvi
Published: April 2015

The paper presents the results of three dimensional flow measurements behind the trailing edges of an impulse turbine blade row of 120° deflection in an annular cascade. The entry boundary layer thickness was systematically varied on the hub and casing walls separately and its effect on secondary flows and losses is investigated. With the increase of entry boundary layer thickness, it has been found that (i) the contours of local loss coefficient show that the magnitude of the hub loss core increased, (ii) the loss cores near the hub and casing wall are convected away from the walls, (iii) the spanwise variation of the pitchwise averaged losses indicate that the position of large loss peak near the hub wall remains the same, but the magnitude of the loss increases, (iv) the exit static pressure increases and the exit velocity in general decreases, (v) the degree of underturning of flow increases and (vi) the net secondary losses do not change appreciably.
Effect of Air Pressure Upon Spray Angle/Width Characteristics of Simplex Pressure Swirl Atomizers
Authors: Parsons J. A. , Jasuja A. K.
Published: April 2015

This paper examines the spatial distribution characteristics of fuel sprays emanating from simplex pressure swirl atomizers of the type commonly used in the gas turbine engine. Three different atomizers were tested on kerosine at chamber gas pressures up to 1377 KN/m2 and fuel pressure drops up to 3448 KN/m2. A non-intrusive, still photographic technique was developed for recording the spray profiles over the entire range of test conditions. Analysis of the experimental data shows that the closing in of the spray boundaries due to an increase in air pressure is a result of the aerodynamic interaction between the fuel spray and its gaseous environment — the nozzle hydrodynamics apparently exercising no influence. Experimental data collected in the study reveals the influence of gas pressure (Pa) upon the half width (y) of the spray envelope at a downstream distance of 30mm from the nozzle face to be described adequately by the expression y α Pa-0.26.
Production and Development of Secondary Flows and Losses Within Two Types of Straight Turbine Cascades: Part 2 — A Rotor Case
Authors: Yamamoto A.
Published: April 2015

Part 1 of this paper[1] presented the detailed mechanism of secondary flows and the associated losses occurring within a straight stator cascade with a relatively low turning angle of about 65°. Significant contribution of secondary flows on the loss production process was shown only near the blade suction surface downstream from the cascade throat (Z/Cax=0.74) in which region flows decelerated due to adverse pressure gradient.

In the second part, the same experimental analysis was applied to a straight rotor cascade with a much larger turning-angle of 102°. Flow surveys were made at twelve traverse planes located throughout the rotor cascade. The larger turning results in a similar but much stronger contribution of the secondary flows on the loss developing mechanism. Evolution of overall loss starts quite early within the cascade, and the rate of the loss growth is much larger in the rotor case than in the stator case.
Three-Dimensional Flowfield Calculation of High-Loaded Centrifugal Compressor Diffusers
Authors: Teipel Ingolf , Wiedermann Alexander
Published: April 2015

In this paper a method for calculating inviscid three-dimensional flowfields in vaned diffusers of high-loaded centrifugal compressors will be considered. Following the classical theory of Wu different kinds of stream surfaces have been introduced. The complete three-dimensional result is approximated by a combination of blade to blade stream surfaces (S1-surface) and S2-surfaces between the side walls of the diffuser. The geometry of the stream sheets depends on each other. A special curvilinear coordinate system has been introduced to take into account the twisted shape of the surfaces.
The Off-Design Performance of a Low Pressure Turbine Cascade
Authors: Hodson H. P. , Dominy R. G.
Published: April 2015

The ability of a given blade profile to operate over a wide range of conditions is often of the utmost importance. This paper reports the off-design performance of a low pressure turbine rotor root section in a linear cascade. Data were obtained using pneumatic probes and surface flow visualisation. The effects of incidence (+9, 0, −20 deg.), Reynolds No. (1.5, 2.9, 6.0×105), pitch-chord ratio (0.46, 0.56, 0.69) and inlet boundary layer thickness (0.011, 0.022 δ*/C) are discussed. Particular attention is paid to the three-dimensionality of the flow field. Significant differences in the detail of the flow occur over the range of operating conditions investigated. It is found that the production of new secondary loss is greatest at the lower Reynolds numbers, positive incidence and the higher pitch-chord ratios.
Three-Dimensional Flows and Loss Reduction in Axial Compressors
Authors: Dong Y. , Gallimore S. J. , Hodson H. P.
Published: April 2015

Measurements have been performed in a low speed high reaction single stage axial compressor. Data obtained within and downstream of the rotor, when correlated with the results of other investigations, provide a link between the existence of suction surface-hub corner separations, their associated loss mechanisms and blade loading. Within the stator, it has been shown that introducing a small clearance between the stator blade and the stationary hub increases the efficiency of the stator compared to the case with no clearance. Oil flow visualisation indicated that the leakage reduced the extensive suction surface-hub corner separation that would otherwise exist. A tracer gas experiment showed that the large radial shifts of the surface streamlines indicated by the oil flow technique were only present close to the blade. The investigation demonstrates the possible advantages of including hub clearance in axial flow compressor stator blade rows.
A Critical Evaluation of Three Centrifugal Compressors With Pedigree Data Sets: Part 5 — Studies in Component Performance
Authors: Japikse David
Published: April 2015

A series of three centrifugal compressor data sets, each passing rigorous tests for quality, has been completed. Using this data base, single-zone and two-zone modeling is thoroughly critiqued in order to judge the appropriateness of such modeling and, hence, to set guidelines for subsequent design optimization using either single-zone or two-zone modeling.
Analytical Solution for the Matrix- and Fluid-Temperature Distribution in Rotating Regenerators
Authors: Niggemann Michael
Published: April 2015

In a rotary regenerator, the matrix- and fluid-temperature distribution in space and time on either side (hot and cold) of the matrix is governed by a coupled system of partial differential equations (PDEs). These are derived from a heat balance under the usual assumption that heat transfer between fluid and matrix is by convection only.

The system of PDEs for the temperature distribution has generally been believed to be not analytically solvable in the case of a regenerator with finite heat transfer coefficients.

In this paper, the analytical solution is given by means of a Laplace transform combined with linear operator theory.

Furthermore, an iterative numerical scheme for calculating the regenerator performance under steady state and transient conditions, based on the analytical representation, is given.
Coal-Fired Gas Turbines for Marine Propulsion Applications
Authors: Kuo Simion C.
Published: April 2015

This paper discusses the prospects of using coal as the primary source of energy to power gas turbines for marine propulsion applications. The problems associated with burning coal for generating power are reviewed in terms of their inherent limitations, environmental effects, compatibility with turbomachinery combusters, and economic considerations. Various forms of coal-based heat sources and their applicable combuster system configurations are identified. Integration of these fuel/combustor combinations with different gas turbine cycles yields a number of possible coal-fired gas turbine systems. A comparison of these candidate systems with marine propulsion system requirements resulted in the selection of a COGAS system burning coal-oil slurry. Candidate COGAS system configurations are presented, and the overall propulsion engine performance is defined.

A baseline coal-oil fired marine COGAS propulsion system was selected, and its performance characteristics were estimated, taking into account the exhaust gas flow effect on the waste-heat steam generator. The payload capabilities and endurance limitations for a coal-fired COGAS ship are presented and compared with those of a conventional oil-fired ship to show the possible fuel cost savings.
Considerations in Retrofitting Gas Turbine Governors
Authors: Paling William M.
Published: April 2015

The paper examines some aspects which should be examined in specifying and selecting replacement gas turbine governors.

It explores the subject from the point of view of the engine manufacturer in his investigations and studies of the original supplied governor. It examines some aspects of the liaison required between the governor engineer, the User and the mechanical, combustion, performance and heat transfer engineers to define governor functions.

Having established functional requirements it then considers aspects such as reliability, failure mode, documentation and a plan for the retrofit.
Telemetry Measurement of Combustion Turbine Blade Vibration in a High Temperature Environment
Authors: Gabriel F. K. , Donato V.
Published: April 2015

Rotating component measurements in a combustion turbine continues to be a most difficult instrumentation problem. Measurements in the turbine high temperature environment makes the problem even more challenging. This paper presents an approach in overcoming the difficulties of acquiring accurate stress data from turbine blades during full load operation. Through the application of existing electronics, which were adapted for these special hostile conditions, a reliable telemetry technique for obtaining dynamic strain gage data of combustion turbine blading is demonstrated.
Determination of the Flow Field in LP Steam Turbines
Authors: Wachter J. , Eyb G.
Published: April 2015

Up to now the determination of flow conditions across the entire circumference in LP steam turbines appears to be a difficult undertaking. The difficulties are mainly caused by the condensing medium steam and by the limited access to the stage from outside. The Last Stage Test Stand at the University of Stuttgart is a suitable facility for flow measurements in the LP part of steam turbines. Besides a short description of the test stand itself, the measuring equipment and the newly developed methods for data acquisition and evaluation are presented. Finally the flow field behind the last stage is shown and the results interpreted.
Fuel Effects on Aircraft Combustor Emissions
Authors: Reeves Curtis M. , Lefebvre Arthur H.
Published: April 2015

Results of an analytical program to determine the effects of broad variations in fuel properties on the pollutant emissions generated by several prominent turbojet engine combustion systems, including both tubo-annular and annular configurations, are presented. Measurements of mean drop size conducted at representative engine operating conditions are used to supplement the available experimental data on the effects of combustor design parameters, combustor operating conditions, and fuel type, on pollutant emissions.

The results of the study indicate that the fuel’s physical properties that govern atomization quality and evaporation rates have a significant effect on the emissions of carbon monoxide and unburned hydrocarbons. Analysis of the available experimental data shows that the influence of fuel chemistry on the emissions of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen, is small. Smoke emissions are found to be strongly dependent on combustion pressure, primary-zone fuel/air ratio, and the mode of fuel injection (pressure atomization or airblast). Fuel chemistry, as indicated by hydrogen content, is also important.

Equations are presented for the correlation and/or prediction of exhaust emissions in terms of combustor size, combustor geometry, engine operating conditions, fuel spray characteristics, and fuel type.
A Gas Turbine Cogeneration Plant With a Gross Electrical Efficiency of Over 50%
Authors: Broekhuizen A. L. , van Lavieren R. R. , Kamminga P.
Published: April 2015

District heating projects in the Netherlands are cogeneration projects with special emphasis on high-efficiency power generation. Together with their customer N.V. IJsselcentrale, Thomassen International B.V., designed a cogeneration system based on gas and steam turbines. The system has following main features:

- the gross electrical efficiency of the system is over 50%, which is a highly remarkable achievement in power generation

- the main components, 2 gas turbines, a steam turbine and one generator are mounted in line on a single shaft.

Successful start up of the plant happened in November 1985, performance tests have shown the target of power generation with an efficiency of 50% is met.
Erosion and Corrosion Considerations for PFBC Gas Turbine Expanders
Authors: Wright I. G. , Stringer J.
Published: April 2015

Considerable interest has been developed over the past few years in the application of gas turbines to expand the hot, dirty flue gases from pressurized fluidized-bed combustors (PFBCs) burning coal. Although no full-size gas turbine has yet operated on a PFBC, firm commitments have been made to build commercial PFBC-GT power plants. In addition, there are a number of projects at various stages of development aimed at operating gas turbines on dirty fuels ranging from the expansion of flue gas from the combustion of pulverized coal, to the direct firing of coal-water mixtures. Common concerns of all these applications include erosion and corrosion of the gas turbine hot gas path components. This paper attempts to provide an overview of results of research and testing so far reported in these areas, and to make an assessment of the engineering trade-offs required for the successful operation of PFBC gas turbine expanders.
Selection of High Performance Low Flow Compressors
Authors: Sayyed S.
Published: April 2015

With rapidly escallating energy costs, the need to use energy as efficiently and economically as possible has led to new development programs particularly in the low flow areas. New techniques in the design of impellers as well as stationary flow passages have been developed to produce highly efficient compression stages, and at the same time calculation methods to accurately predict the aerodynamic performance for low flow applications are being continually upgraded to provide a reliable and efficient machine to be employed in the emerging applications.

This paper provides some of the insights, which need to be considered when selecting low flow high performance centrifugal compressors.
Atomization and Combustion Characteristics of Antimisting Fuels Using JT8D and Air-Boost Injectors
Authors: Kennedy Jan B. , Fiorentino Anthony J.
Published: April 2015

An experimental evaluation of a bill-of-material JT8D injector, a low emission airblast JT8D injector, and an air-boost injector has been conducted at United Technologies Research Center to determine the atomization levels of antimisting fuels at operating conditions simulating engine conditions. In addition, Pratt & Whitney has evaluated the effects of using antimisting kerosene (AMK) on the performance of the components from the fuel system and the combustor of the current in-service JT8D aircraft engine. Spray characterization tests were conducted at ambient conditions using six different fuels, i.e. Jet A, one and three-pass JT8D fuel pump degraded, one and two-pass Gaulin degraded, and undegraded AMK fuels. The results of the tests indicated that the use of AMK fuel causes a noticeable decline in the quality of the spray and specifically a large increase in the Sauter Mean Diameter (SMD) for all three injectors. The undegraded AMK fuel resulted in a grossly incomplete atomization of the fuel with the spray being characterized by ligaments of fluid rather than droplets. In addition, the idle patternation data indicated that the low emission injector fuel distribution changed from a hollow cone Jet A spray with no fuel in the center to a semi-hollow spray cone using the 1- and 3-pass AMK, and this change could disrupt the primary zone recirculation pattern. Processing the AMK using the JT8D fuel pump as the degrader enhanced the atomization and spray quality, but combustion tests at P&WA using the JT8D degraded fuel indicated that the emissions levels produced were excessive and the lean blowout, relight and starting characteristics were somewhat deficient. The results from the spray quality and combustor performance tests coupled with the P&WA fuel component laboratory evaluations pointed out the need for extensive AMK degradation. Based on the levels of degradation required for successful cold filter tests and the transition velocities measured with Jet A fuel, AMK was processed with a Gaulin homogenizer to transition velocities of 5 and 9 cm/sec. Subsequent spray quality evaluations with these two levels of degraded fuels and Jet A using the JT8D airblast low emission fuel injector indicated that the gross characteristics of the Jet A and the degraded AMK fuels were similar. Perhaps even more important was the distribution data at idle, where the highly degraded fuels were almost indistinguishable from Jet A. Based on the early combustion results, it is implied that low power emissions might be very close to Jet A using the Gaulin degraded fuels.
Development, Installation and Operating Results of a Steam Injection System (STIG™) in a General Electric LM5000 Gas Generator
Authors: Burnham James B. , Giuliani Michael H. , Moeller David J.
Published: April 2015

This paper describes the first full scale field test of a steam injection system for a natural gas fired G.E. LM5000 gas generator for the purpose of: (A) decreased exhaust emissions, (B) increased power output, and (C) improved efficiency. It discusses the steam supply system, engine features, test results and plant economics for steam injection into the combustor and compressor discharge sections of the LM5000 at rates up to 65,000 LB/HR (29,510 KG/HR).
The Dynamics of Suspended Solid Particles in a Two Stage Gas Turbine
Authors: Tabakoff W. , Hamed A.
Published: April 2015

Gas turbine engines operating in dusty environments are exposed to erosion and performance deterioration. In order to provide the basis for calculating the erosion and performance deterioration of turbines using pulverized coal, an investigation is undertaken to determine the three dimensional particle trajectories in a two stage turbine. The solution takes into account the influence of the variation in the three dimensional flow field. The change in particle momentum due to their collision with the turbine blades and casings is modeled using empirical equations derived from experimental Laser Doppler Velocimetry (LDV) measurements. The results show the three dimensional trajectory characteristics of the solid particles relative to the turbine blades. The results also show that the particle distribution in the flow field are determined by particle-blade impacts. The results obtained from this study indicate the turbine blade locations which are subjected to more blade impacts and hence more erosion damage.
The Part-Load Performance of a Gas Turbine Engine With Two Turbines Working in Parallel
Authors: Najjar Yousef S. H. , Aldoss Taha K.
Published: April 2015

To reduce the inefficiency and the drawbacks incurred by reheat in a gas turbine engine with the two turbines in series, a parallel arrangement is investigated. The combustion gases expand to atmospheric pressure in each turbine. One of the turbines drives the compressor to which it is mechanically coupled while the other develops the power output of the plant.

Two methods of control for the reduction of power are considered:

a) Varying the fuel supply to the combustion chambers so that the inlet temperature to the turbine driving the compressor is constant, while the inlet temperature to the power turbine is reduced.

b) Reducing both temperatures while keeping them equal.

The effects of turbines inlet temperatures, pressure ratio and pressure loss in combustion chambers on the cycle efficiency and power output are studied and a sensitivity analysis is carried out, with the aid of a specially constructed computer program.

The first method of control proved to be superior.
Particle and Vapor Deposition in Coal-Fired Gas Turbines
Authors: Ahluwalia R. K. , Im K. H. , Chuang C. F. , Hajduk J. C.
Published: April 2015

Mechanistic models have been developed for particle and vapor deposition on the blades of coal-fired gas turbines. The particle deposition models include the simultaneous contribution of Brownian and turbulent diffusion, thermophoresis, eddy impaction, and inertial impingement. The diffusive mechanisms have been validated against experimental data for low-speed cascade flow and particle-laden flow through pipes. The inertial deposition treatment is shown to collapse to the well-known expression for particle capture in a flow turning around a bend. A method is presented for calculating Na2SO4 and K2SO4 vapor deposition on cooled blades. Scaling laws are formulated for estimating the contribution of boundary layer homogeneous and heterogeneous nucleation mechanisms for highly cooled turbine blades.