bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the Rear Stage Casing Treatment on the Overall Performance of a Multistage Axial-Flow Compressor
Authors: Gao Yao-Lin , Li Ke-Ming
Published: April 2015

This paper discusses the effect of tip treatment in the rear stages of a compressor on the high speed stall margin and efficiency. A nine stage engine compressor was tested in a rig with and without casing treatment on the tip sections of the last three rotors. Another series of tests were conducted on a modified compressor with twisted rotor blades in the rear stages. For both compressors, tip treatment improved high speed surge margin. The first compressor encountered no loss of efficiency with the addition of tip treatment, but the second compressor suffered a loss of efficiency.
Investigation of the Laminar-Turbulent Transition of Boundary Layers Disturbed by Wakes
Authors: Pfeil H. , Herbst R. , Schröder T.
Published: April 2015

The boundary layer transition under instationary afflux conditions as present in the stages of turbomachines is investigated. A model for the transition process is introduced by means of time-space distributions of the turbulent spots during transition and schematic drawings of the instantaneous boundary layer thicknesses. To confirm this model, measurements of the transition with zero and favorable pressure gradient are performed.
Accuracy Expectations for Gas Turbine and Centrifugal Compressor Performance Testing
Authors: Heard T. C. , Hipp E. J.
Published: April 2015

Engineers inexperienced with testing or interpretation of test results from gas turbine/centrifugal compressor sets may not be familiar with the uncertainties stemming from measuring instrument and reading errors. This may be because only a few specialists are acquainted with the applicable engineering statistics and acceptable measurement accuracy levels, but it is also probably due to the unavailability of clear, simply worded documentation of the principles involved. Because there are significant uncertainties in power and specific fuel consumption results of such tests, it is important for concerned engineers to recognize and to develop a sensitivity for the various measurement errors and to take them into account when judging the actual equipment performance. This paper outlines a simple procedure for estimating instrument errors and for assessing their influences on the final results. In addition it illustrates justifiable accuracy expectations of gas turbine/compressor system tests and it may be a starting reference for those interested in the subject.
An Empirically-Based Simulation Model for Heavy-Duty Gas Turbine Engines Using Treated Residual Fuel
Authors: Blanton J. C. , O’Brien W. F.
Published: April 2015

An empirically-based engine simulation model was developed to analyze the operation of a heavy-duty gas turbine on ash-bearing fuel. The effect of the ash in the combustion products on turbine efficiency was determined employing field data. The model was applied to the prediction of the performance of an advanced-cooled turbine engine with a water-cooled first-stage nozzle, when operated with ash-bearing fuels. Experimental data from a turbine simulator rig were used to estimate the expected rates of ash deposit formation in the advanced-cooled turbine engine, so that the results could be compared with those for current engines. The results of the simulations indicate that the rate of decrease in engine power would be 32 percent less in the advanced-cooled engine with water cooling. An improvement in predicted specific fuel consumption performance was also noted, with a rate of increase of 38 percent for the advanced-cooled engine.
Tuning of Turbine Blades: A Theoretical Approach
Authors: Gudmundson P.
Published: April 2015

A perturbation method is described which predicts the changes in eigenfrequencies resulting from geometrical changes of a structure. This dependence is represented by dimensionless functions, one for each eigenfrequency, which vary over the surface of the structure. The functions are presented for each eigenfrequency as isoline plots. An easily estimated integration of these functions allows one to predict a geometrical change which results in a desired change in the resonance frequencies. The method was applied to a turbine blade and a rectangular beam. For the turbine blade isoline plots are presented for the first five eigenfrequencies. Eigenfrequency changes up to 8 percent were modeled accurately.
Coalification, Coal Structure and its Impact on Associated Engineering Problems
Authors: Raj S. , Raj R.
Published: April 2015

Coal is not a simple substance, but a complicated mixture of organic and inorganic structures. In this paper, physical, chemical and biological factors influencing the coalification process are discussed. The various structures of coal and how the selection of coal can influence various engineering decisions are discussed.
Measured Particle Rebound Characteristics Useful for Erosion Prediction
Authors: Wakeman T. , Tabakoff W.
Published: April 2015

Extensive high temperature particle rebound testing has been continuing at the University of Cincinnati for the past three years utilizing the new high temperature material erosion facility. Particle rebound characteristics including particle angle and velocity restitution ratios are important in the prediction of particle trajectories through a turbomachine or other flow devices where particulate erosion is present and the prediction of erosion patterns is desired. This paper presents particle rebound data which has been accumulated for 160 microns particles impinging on INCO 718, Ti 6-4 and 2024 AL targets. Particle rebound characteristics are compared with important parameters such as target temperature, particle impingement velocity and particle impingement angle. In addition a semi-empirical erosion rate equation for INCO 718 material is derived.
Indirect Pulverized-Coal Fired Air Heaters for Gas Turbine Service
Authors: Anson D. , Hazard H. R. , Flanigan L. J.
Published: April 2015

This paper discusses design considerations for pulverized-coal fired indirect heaters for gas turbines and presents results of model studies of flow and mixing for a heater design. Analysis shows that flue-gas recirculation can reduce peak flame temperature without reducing flame stability, leading to smoothing of radiation to gas-cooled furnace walls. This, in turn, results in acceptable tube-metal temperatures. Experimental model studies of flow and mixing in a single burner, and in a complete furnace model with 12 burners, show that excellent mixing can be obtained in a small volume, with flue gas injected so as to mix downstream of the burner flameholding region.
The Optimum Design of Stepped Shafts: A Study in Computational Optimization
Authors: Maday C. J.
Published: April 2015

Optimum stepped shaft designs are obtained through an application of Pontryagin’s Minimum Principle. Optimum designs are obtained for a given critical speed of specified order. Indexes of Performance to be minimized include mass and rotating inertia. A general problem formulation illustrates how constraints on stress, deflections, and geometric design are taken in account. Numerical solutions are obtained to nonlinear multi-point-boundary-value-problems. A Newton-Raphson algorithm was developed to determine step locations precisely in order to facilitate the convergence of the shooting method used to solve the boundary value problem. Numerical solutions are determined with an assumed critical speed; a Rayleigh quotient calculation is used to verify that the optimum design possesses the assumed value.
Measurements of Heat Transfer Coefficients on Gas Turbine Components: Part II — Applications of the Technique Described in Part I and Comparisons With Results From a Conventional Measuring Technique and Predictions
Authors: Beacock R. J. , Horton F. G. , Kirker T. J. , White A. J.
Published: April 2015

An experimental technique, described in Part I, for the measurement of local, convective heat transfer coefficients around hollow, thin walled, internally cooled components has been applied to gas turbine aerofoils operating at high pressure and temperature. Both experimental technioques provide data for use in improving design methods and comparisons with predictions using current design methods are presented.
Gas Turbine Design for Maintenance
Authors: Wisch H. H.
Published: April 2015

The modern gas turbine power plant is considerably more than a grouping of equipment assembled to perform a function. It is a complex integration of sub-systems and components which must work together reliably if high availability is to be achieved. Even the most reliable equipment, however, requires periodic or scheduled maintenance and also requires unscheduled maintenance (i.e., forced outage) as functional failures occur. Since availability is directly influenced by maintenance downtime, it is essential that power plants be designed with maintainability as a key consideration. Provisions can be readily designed into equipment which can reduce the lengths of outages, permit outages to be deferred, or to enable certain types of outages to be avoided altogether. Other provisions can be made to avoid operating and maintenance errors, and to effect faster and more accurate problem diagnosis. It is also possible to improve the availability of existing equipment by the incorporation of maintenance measures proposed in this paper.
A Stage-by-Stage Dual-Spool Compression System Modeling Technique
Authors: Davis M. W.
Published: April 2015

Mathematical compressor models are major tools used in resolving engine problems and evaluating the influence of compressor modifications on performance and stability. This paper discusses the development of a one-dimensional, time-dependent, dual-spool, stage-by-stage compression system mathematical model and its application to a current compression system. The dual-spool model was constructed by extending a current single-spool modeling technique to include dual-spool compression systems. To improve the numerical stability characteristics of the compressor modeling technique, the dual-spool model was formulated using MacCormack’s explicit differencing scheme and a method of characteristics boundary treatment. The dual-spool model was applied to a current compression system, and several types of planar destabilizing disturbances were studied to determine their effect on compression system stability. Model predictions were validated against experimental data whenever possible.
Low Temperature Starting of the M1 Battle Tank
Authors: Drury E. A.
Published: April 2015

This paper discusses the results of an investigation of the discharge characteristics of military type lead-acid and nickel-cadmium batteries at extreme low temperatures and lead to the development of a reliable method for starting the M1/M60 Tank APU. The rotating cup fuel atomization system used in the APU proved to be very well-suited for starting the APU over the extremes of the environment with all types of diesel fuels and JP-4 jet fuel and consistently provided reliable operation at ambient temperatures as low as −70°F (−56.7°C). This proven capability of the APU provided the only means for successful starting of the Lycoming AGT-1500 main engine of the Abrams Ml Battle Tank at ambient temperatures below −25°F (−31.7°C) during low temperature tests in the Eglin AFB Climatic Laboratory and cold region field tests at Fort Greeley, Alaska.
The Fluid Dynamics of Turbomachinery Program: Objectives, Organization and Results
Authors: Serovy G. K. , Okiishi T. H.
Published: April 2015

Since 1968, an advanced educational program in the fluid dynamics of turbomachinery has been offered by the ASME Turbomachinery Institute at Iowa State University. Initiated by concerned individuals to help meet the need for high-level, continuing education in this field of specialization, the course appears to be accomplishing its original intent. The success of the program can be attributed to a number of factors including a good faculty, an eager and qualified group of participants, and scholarly surroundings. As might be expected, timely and thoughtful planning, good luck and competent support are also essential. Of the many lessons learned about this kind of educational effort, several seem important enough to report in this paper.
Combustion of Medium Heating Value Coal Gas at Turbine Operating Conditions
Authors: Schwab J. A. , Cicero D. C. , Basel R. S.
Published: April 2015

The work described in this paper is part of the effort performed under Department of Energy (DOE) Contract DE-AC21-80ET14752. The primary objective of this contract is to demonstrate the viability of the Westinghouse pressurized, fluidized bed gasification process for production of low and medium heating value fuel gas. One of many secondary objectives is to conduct combustion tests with medium heating value gas produced by the DOE/Westinghouse gasifier. In late 1980 and 1981, tests were performed on an experimental Westinghouse combustor during normal gasifier operation at the Test and Development Center. Pollutant emissions and combustion efficiency were evaluated as a function of inlet temperature, air-to-fuel ratio, pressure and reference velocity. Results for medium heating value gas combustion are presented along with combustion test results on distillate and coal derived liquid fuels.
TURBOTRANS: A Programming Language for the Performance Simulation of Arbitrary Gas Turbine Engines With Arbitrary Control Systems
Authors: Palmer J. R. , Cheng-Zhong Yan
Published: April 2015

A generalized modular digital computer code — TURBODYNE — is shown to be a flexible easily coded high-level programming language for the steady-state and transient performance simulation of arbitrary gas turbine engines with arbitrary control systems. The configuration of the engine and control system can be simply described by using “CODEWORDS” corresponding to the various components and processes of both engine and control systems. TURBOTRANS is an analytical tool for performance simulation of gas turbine engines with their control systems. Its modular structure facilitates additional features when required.
High Temperature Erosion-Corrosion in Gas Turbines
Authors: Stringer J.
Published: April 2015

Under certain circumstances, hot gases containing particulates may be expanded through a turbine. The erosion damage due to the particulates interacts with the high temperature oxidation processes. The interaction may be positive: the oxide layer may be more erosion-resistant than the substrate. The interaction may be negative: the erosion can remove the protective oxide resulting in accelerated metal loss. If the gases contain corrosive materials such as alkali sulfates as well as the particulates, further interactions are possible. These processes are of importance in gas turbine expanders for pressurized fluidized bed combustors burning coal, and several research projects are in progress to study them.
Net Shape Fabrication of Alpha Silicon Carbide Turbine Components
Authors: Storm R. S.
Published: April 2015

Development of Alpha Silicon Carbide components by net shape fabrication techniques has continued in conjunction with several turbine engine programs. Progress in injection molding of simple parts has been extended to much larger components. Turbine rotors fabricated by a one piece molding have been successfully spin tested above design speeds. Static components weighing up to 4.5 Kg (10 lb) and 33 cc (13 in.) in diameter have also been produced using this technique. Use of sintering fixtures significantly improves dimensional control. A new Si-SiC composite material has also been developed with average strengths up to 1000 MPa (150 ksi) at 1200°C.
Materials Selection for Metallic Heat Exchangers in Advanced Coal-Fired Heaters
Authors: Wright I. G. , Minchener A. J.
Published: April 2015

The application of advanced coal-fired heaters to heat the working fluid for a closed-cycle gas turbine provides some challenging problems for the selection of metallic heat-exchanger materials. The requirements of a working fluid temperature bf 1550 F (1116 K) at a pressure of 300–600 psig (2.07–4.14 MPa/m2) necessitate the alloys used for the hottest part of the heat exchanger must possess high-temperature strength in excess of that available in widely used alloys like alloy 800. The maximum-duty alloys must therefore be selected from a group of essentially nickel-base alloys for which there is scant information on long term strength or corrosion resistance properties. The susceptibility to corrosion of a series of candidate heat exchanger alloys has been examined in a pilot plant size fluidized-bed combustor. The observed corrosion behavior confirmed that at certain locations in a fluidized-bed combustor nickel-base alloys are susceptible in varying degrees to rapid sulfidation attack, and must be protected by coating or cladding.
Development of 20,000 to 50,000 HP Aircraft-Derivative Gas Turbines
Authors: Takeo K. , Shimura Y.
Published: April 2015

A new gas turbine, the IM5000, which has changed the image of a gas turbine plant in view of specific size and efficiency, has been developed. In 1980, Ishikawajima-Harima Heavy Industries Co., Ltd., completed the lineup of aircraft-derivative gas turbines ranging from 15,000 to 50,000 hp when the company developed two new models in the 20,000 to 25,000 hp class, the IM2000 and the IM2500. To establish high reliability of the power turbine, an extensive investigation of the rotor assembly was completed. Engine test runs were conducted to confirm blade vibratory stresses through the whole operating range. The stress levels thus obtained revealed far below the critical limit and no detrimental resonance would be expected. The same attempt was adopted on the IM2500 power turbine which was developed in 1980. Through these two engine operations, the measuring method of blade vibratory stresses by means of strain gauges was established. Besides analyses of the rotating parts, analyses and experimental testing have been carried out on the stationary parts.
An Improved Time Marching Method for Turbomachinery Flow Calculation
Authors: Denton J. D.
Published: April 2015

Time marching solutions of the Euler equations are now very widely used for the calculation of flow through turbomachinery blade rows. All methods suffer from the disadvantages of shock smearing, lack of entropy conservation, and comparatively long run times. A new method is described which reduces all these problems. The method is based on the author’s opposed difference scheme, but this is applied to a new type of grid consisting of quadrilateral elements which do not overlap and have nodes only at their corners. The use of a nonoverlapping grid reduces finite differencing errors and gives complete freedom to vary the size of the elements. Both these factors help to improve entropy conservation. Considerable savings in run time (by a factor of about 3) are obtained by using a simple multigrid method whereby the solution is advanced simultaneously on a course and on a fine grid. The resulting method is simpler, faster, and more accurate than its predecessor.
A Non-Iterative Precise Method for Open Gas Turbine Cycle Calculation
Authors: Lee W. H.
Published: April 2015

A non-iterative solution of the gas turbine combustion chamber energy balance equation is developed which accounts for the effects of temperature and fuel-air ratio on the enthalpies of the working media. Based on this solution an efficient precise procedure for calculating open gas turbine cycle can be outlined using available gas tables of stoichiometric combustion products for the consideration of different hydrocarbon fuels. Order of computational accuracy comparable to that of steam cycle calculation using modern steam table may be expected.
Physical Vapor Deposition of Ceramic Coatings for Gas Turbine Engine Components
Authors: Demaray R. E. , Fairbanks J. W. , Boone D. H.
Published: April 2015

The use of ceramic coatings on gas turbine engine hot section airfoils has the potential for major improvements in engine performance, durability, and fuel economy, for both industrial/utility and flight engine applications. Major improvements in the durability of ceramic thermal barrier coatings for turbine engine application have been made in both hot corrosion resistance and ceramic thermal cycle fatigue. This paper describes the early history, as well as, recent success in the development of mechanically segmented or “microcolumnar” structured coatings that are produced by electro-beam, physical vapor deposition (P. V.D.) of ceramic materials on metallic turbine airfoil components. Due to their columnar structure, these coatings accommodate the thermal cycle stresses that develop between the ceramic coating and the metal substrate due to their very different coefficients of thermal expansion. The hot corrosion, erosion, and thermal fatigue protection properties are also discussed.
The Nuclear Gas Turbine: A Perspective on a Long-Term Advanced Technology HTGR Plant Option
Authors: McDonald C. F. , Peinado C. O.
Published: April 2015

Design studies and assessments were carried out in the 1970s on an advanced, direct-cycle high-temperature gas-cooled reactor (HTGR) option. These led to conclusions in 1980 that an extensive development effort was necessary to establish a technically viable gas turbine HTGR (HTGR-GT) plant to satisfy demanding safety and licensing criteria and that further design innovation was necessary to identify plant features for improved economics. The steam cycle HTGR was designated as the lead plant and the HTGR-GT classed as a long-term, advanced technology, second-generation HTGR plant option. With the necessary development, a dry-cooled gas turbine plant with a reactor outlet temperature of approximately 950°C, operating in a combined cycle mode or cogeneration mode, could be realized. This paper reviews the status of the Brayton cycle plant and gives a perspective on the HTGR-GT plant as a follow-on option to the steam Rankine cycle lead plant.
A Model for Computation of Net Local Soot Generation
Authors: Koussa S. S.
Published: April 2015

A model which is believed to be a positive step towards finding a model appropriate for detailed prediction of soot concentration in practical combustors is presented. The model considers the effect of turbulence on soot formation and destruction without excessive penalty on multidimensional computations. Comparison of the predictions with some experimental data shows that the general trends may be predicted with accuracy acceptable in most practical cases.
Oil Field Experience With Gas Turbine-Driven Compressor Stations
Authors: Saadawi H.
Published: April 2015

Specifying and selecting equipment for gas compression projects is a complex process involving many engineering disciplines. All the alternatives and the possible interaction between the various components in the system should be carefully examined by the project team. The accumulation of errors in evaluating the system characteristics during the project engineering phase, can lead to the gas compression system not performing to design specifications. This paper describes the problems encountered with the compressor package during the commissioning of four gas turbine-driven compressor stations for gas lift in one of the onshore oilfields in the Middle East. Solutions to these problems are also outlined.
Secondary Flow Mixing Losses in a Centrifugal Impeller
Authors: Johnson M. W. , Moore J.
Published: April 2015

Detailed flow measurements made in a 1-m dia shrouded centrifugal impeller running at 500 rpm are presented. All 3 mutually perpendicular components of relative velocity and rotary stagnation pressures were measured on 5 cross-sectional planes between the inlet and the outlet, using probes which were traversed within the rotating impeller passage. The reduced static pressures were also calculated from these flow measurements. The measurements were made for an impeller flow rate corresponding to approximately zero incidence at the blade leading edges. Shroud boundary layer separation and secondary flow were observed to lead to the formation of a wake in the suction-side/shroud corner region. It is concluded that the turbulent mixing associated with the shroud boundary layer separation and the strength of the secondary flow strongly influence the size and location of the wake respectively.
Residual Fuel Experience on a General Electric MS7001 Gas Turbine in Suriname, South America
Authors: Lynch J. R. , Charron M. A. , Baank J.
Published: April 2015

This paper documents the operation of a General Electric MS7001 gas turbine on residual fuel. Proof of this capability will allow utilities an option on fuel selection which will reduce their operating costs. The background on the site power needs and selection of the gas turbine equipment are discussed. The operational status of this turbine with over 20,000 fired hours almost all of which is on residual oil are presented. The system operation of the gas turbine including power loss and data due to ash deposits and turbine cleaning methods and effectiveness are discussed. The results of a hot gas path inspection at 11,932 fired hours are also shown. An economic analysis of this residual fuel fired gas turbine compared to the same turbine if operated on distillate only is presented.
EAGLE: An Interactive Engine/Airframe Life Cycle Cost Model
Authors: Reed E. J. , Horton R. R. , Fyfe J. B.
Published: April 2015

A major portion of the Life Cycle Cost (LCC) of a modern high technology weapon system is determined by design decisions made very early in the development process. Many of these decisions are so fundamental that later changes become impractical. As a result, a usage-sensitive, interactive aircraft engine LCC model has been developed by Pratt & Whitney Aircraft to evaluate and prioritize potential technology candidates during conceptual/preliminary design. This paper discusses the development of the EAGLE (Engine/Airframe Generalized LCC Evaluator) model, its validation using results from the Advance Technology Engine Studies (ATES), and includes an example engine technology evaluation.
The Use of Performance-Monitoring to Prevent Compressor and Turbine Blade Failures
Authors: Dundas R. E.
Published: April 2015

Most failures of compressor and turbine blades in gas turbines and axial-flow compressors are due to high-frequency fatigue (neglecting the rare instances of foreign-object ingestion). Fatigue is the result of vibration of the blade, either in resonance or in flutter. With mature machines, the user can avoid the possibility of most resonant-vibration failures by a program of performance monitoring. Flutter can be avoided only if there is reason (such as experience) to expect it in a certain operating regime. Examples of a simple performance-monitoring procedure are given.
Investigation of Flows in Rectangular Diffusers With Inlet Flow Distortion
Authors: Al-Mudhafar M. M. , Ilyas M. , Bhinder F. S.
Published: April 2015

The results of an experimental study on the influence of severely distorted velocity profiles on the performance of a straight two-dimensional diffuser are reported. The data cover entry Mach numbers ranging from 0.1 to 0.6 and several inlet distortion levels. The pressure recovery progressively deteriorates as the inlet velocity is distorted.
Optimization of Compressor Vane and Bleed Settings
Authors: Garberoglio J. E. , Song J. O. , Boudreaux W. L.
Published: April 2015

Optimization of vane and bleed settings in a multistage axial compressor undergoing development is currently a difficult, time consuming, and very expensive process. The current technique usually consists of a detailed manual review of the internal aerodynamics after the baseline tests have been completed. If performance goals have not been met, the designers must estimate how vane and/or bleed settings might be changed to advantage and additional tests carried out until goals are met or time and budget are exhausted. The application of available test facility computer capacity to guide or possibly control the search for optimum compressor performance can ease this burden. This paper presents a numerical search optimization method for guiding the optimization of vane and bleed settings. The main element of the computer program is the COPES/CONMIN approximate optimization algorithm which has been programmed to permit optimization of four variable vane rows and one bleed. Calculations are presented to demonstrate the accuracy that can be achieved and the potential reduction in the number of data points and test time. Measurements on a three-stage, four-variable-vane compressor are presented to demonstrate the feasibility of using the software in conjunction with experimental tests.
An Experimental Investigation of Rotating Stall Flow in a Centrifugal Compressor
Authors: Kämmer N. , Rautenberg M.
Published: April 2015

The flow through a centrifugal compressor impeller and a vaneless diffuser was investigated using unsteady pressure transducers and stationary probes when the compressor operated in the rotating stall region of the compressor map. The inlet velocity profile of the impeller was measured with traversing probes and was found to be significantly different from the profiles measured in an unthrottled condition. A zone of reverse flow was detected close to the suction duct wall as well as a strong swirl induced by the impeller. Circumferentially and meridionally spaced transducers made it possible to determine the stall frequency and the number of stall cells. The amplitude of the flow distortion as a function of meridional position was calculated from meridionally spaced transducers.
Gas Turbine Airflow Control for Optimum Heat Recovery
Authors: Rowen W. I. , Van Housen R. L.
Published: April 2015

Gas turbines furnished with heat recovery equipment generally have maximum cycle efficiency when the gas turbine is operated at its ambient capability. At reduced gas turbine output the cycle performance can fall off rapidly as gas turbine exhaust temperature drops, which reduces the heat recovery equipment performance. This paper reviews the economic gains which can be realized through use of several control modes which are currently available to optimize the cycle efficiency at part load operation. These include variable inlet guide vane (VIGV) control for single-shaft units, and combined VIGV and variable high pressure set (compressor) speed control for two-shaft units. In addition to the normal control optimization mode to maintain the maximum exhaust temperature, a new control mode is discussed which allows airflow to be modulated in response to a process signal while at constant part load. This control feature is desirable for gas turbines which supply preheated combustion air to fired process heaters.
A Two-Dimensional Boundary-Layer Program for Turbine Airfoil Heat Transfer Calculation
Authors: So R. M. C. , Edelfelt I. H. , Elovic E. , Kercher D. M.
Published: April 2015

A two-dimensional boundary-layer program has been developed for the calculation of flow and heat transfer around turbine airfoils. The program is capable of carrying out the calculation from the forward stagnation point, and can account for such effects as compressibility, high inlet gas temperature, streamwise pressure gradient, transition, streamline curvature and freestream turbulence. Three comparisons with recent measurements are carried out. Two are with idealized wind tunnel data. One is with cascade data obtained at high gas-to-wall temperature ratio of 2.56–2.85, which compares with a normal range of 1.4 to 2.4 for real gas turbines. Good agreement is obtained with the wind tunnel data. As for the cascade data, good correlation on the suction surface of the turbine airfoil is achieved. However, discrepancy on the pressure surface is observed and is attributed to the occurrence of local separation and reattachment in the actual flow.
Fuel Treatment and Corrosion of Gas Turbines Burning Residual Fuel: A Survey Report
Authors: Lukas H. , Duncan R.
Published: April 2015

Encotech was commissioned by the Electric Power Research Institute (EPR1) to survey the owners of gas turbines burning residual fuel or crude oil. The survey’s purpose was to identify operating problems, costs, and general owner reaction to burning residual fuel and crude oil. This paper presents an excerpt of the report related to corrosion and fuel treatment as well as additional data.
Gas Turbine Operation in the “Real World”
Authors: Allen Herbert L.
Published: April 2015

The paper discusses the various modes of gas turbine operation in the utility industry and the impact of the environment on the gas turbine operation and repair. Maintenance programs, organization and implementation will be presented in outline form so a new operator, or potentially new operator, can plan ahead to implement an effective preventative maintenance program.
A Review of NASA Combustor and Turbine Heat Transfer Research
Authors: Rudey Richard A. , Graham Robert W.
Published: April 2015

The thermal design of the combustor and turbine of a gas turbine engine poses a number of difficult beat transfer problems. In current designs, there is substantial evidence to indicate that the capability for estimating critical metal temperatures lacks the needed certainty for reliable design practice. Such uncertainty has cost much in terms of money and development time for the newer engines now installed in United States aircraft. The importance of improved prediction techniques becomes more critical in anticipation of future generations of gas turbine engines which will operate at higher cycle pressure and temperatures. Costly development modifications will have to be avoided by being able to predict metal temperatures more accurately.

Research which addressses many of the complex heat transfer processes holds promise for yielding significant improvements in prediction of metal temperatures. Such research involves several kinds of programs including: 1) basic experiments which delineate the fundamental flow and heat transfer phenomena that occur in the hot sections of the gas turbine but at low enthalpy conditions; 2) analytical modeling of these flow and heat transfer phenomena which result from the physical insights gained in experimental research; and 3) verification of advanced prediction techniques in facilities which operate near the real engine thermodynamic conditions.

In this paper, key elements of the NASA program which involves turbine and combustor heat transfer research will be described and discussed. Research conducted within in the laboratories of the NASA Lewis Research Center and sponsored research being performed by universities and industrial laboratories will be included in this review.
MS7001E/Riyadh 7 Sustained Performance
Authors: Petroff C. G. , Gault E. H.
Published: April 2015

Power Plant 7 in Riyadh, Saudi Arabia is comprised of sixteen MS7001E gas turbines. Rated at 800 MW, it is the worlds largest crude oil fueled gas turbine power plant. During the period May 1981 to August 1982, performance tests to determine output and heat rate were conducted on the gas turbines as part of customer acceptance procedures. The units had all accumulated anywhere from 900 to 5000 fired hours prior to the acceptance tests. This paper reviews the results of the performance tests as well as the equipment and procedures which were used to maintain output and efficiency of the units after extended operation.
Operating Experience With Compressors of Large Heavy-Duty Gas Turbines
Authors: Becker B. , Bohn D.
Published: April 2015

The shaft power of compressors in industrial-type gas turbines exceeds that which is attained by any other axial compressors. Their operating efficiency and availability are thus of prime importance expecially since gas turbines are being increasingly utilized for medium-range and base-load electric power generation. In addition to good aerodynamic design of the blading, correct dimensioning of the compressor blades to withstand the static and dynamic stresses that occur under various service conditions is a decisively important prerequisite for reliable operating performance. Measurement of the dynamic stresses is important for design verification and reliability confirmation.

Within the period between scheduled maintenance of a Model V 94 gas turbine, approx. 3,000 kg of solid particles flow through the compressor blading if the intake ambient air has a dust content of 0.1 mg/m3. The possible resulting erosion, corrosion and fowling negatively affect the long-term operating performance. The paper describes how these harmful effects can be effectively combatted by intake-air filtering, machine washing and blade coatings. The operating experience based on over one million service hours, of which more than one-third is with protected blades, demonstrates the success of the recommended compressor protection methods in achieving remarkably high operating availability.
Comparisons of Rational Engineering Correlations of Thermophoretically-Augmented Particle Mass Transfer With STAN5-Predictions for Developing Boundary Layers
Authors: Gökoğlu Süleyman A. , Rosner Daniel E.
Published: April 2015

Fouling (and corrosion) of gas turbine (GT) blading often results from the deposition of materials derived from inorganic impurities in the fuel and/or ingested air. When the depositing material is in the form of a submicron “aerosol” (dust or mist) it has been found that the rates of deposition on cooled surfaces can be augmented by some 100–1000-fold via the mechanism of thermophoresis (particle migration down a temperature gradient). For this reason, in earlier papers we reported the development of rational, yet simple, engineering correlations of thermophoretically-augmented particle transport across both laminar boundary layers (LBLs) and turbulent boundary layers (TBLs). While developed based on theoretical considerations, and numerical computations of self-similar LBLs and law-of-the-wall (Couette flow-like) TBLs, these mass transfer coefficient (Stm-) correlations, when applied locally, may also prove useful in making engineering mass transfer predictions for more complex geometries, including GT-blades. Pending additional controlled experiments, insight into the local applicability of these correlations can be gained by selected comparisons with numerical predictions for developing BLs. This paper reports on our a) modification of the code STAN5 to properly include thermophoretic mass transport, and b) examination of selected test cases of developing BLs which include variable properties, viscous dissipation, transition to turbulence and transpiration cooling. Under conditions representative of current and projected GT operation, local application of our Stm/Stm,o-correlations evidently provides accurate and economical engineering design predictions, especially for suspended particles characterized by Schmidt numbers outside of the heavy vapor range (say, Sc>10).
High Temperature Erosion Study of Metals Used in Turbomachinery
Authors: Tabakoff W. , Wakeman T.
Published: April 2015

Gas turbine engines operating in dusty environments are exposed to severe erosion, especially the compressor and the turbine components. Predicting erosion in rotating machinery is a very complex problem. In order to provide the basis for alloy selection in future turbines using pulverized coal, an investigation is undertaken to obtain a basic understanding of the mechanisms of erosion at high temperatures. For this purpose, a test facility has been designed to simulate the aerodynamic and thermodynamic conditions in the turbine. The effects of high temperature on the erosion rate for different alloys are experimentally determined and the results obtained are presented in this paper. The findings are very important in predicting erosion rate for future turbomachinery exposed to particulate flows.
Multifuel Gasturbine Propulsion for Naval Ships: Part I — Logistic and Operational Rationale
Authors: Prins Roel T. G.
Published: April 2015

Frigates and destroyers of many navies are propelled by aero-derived gasturbines. World wide operation of these ships necessitates the availability of high quality fuel all over the globe. Thus in a modern destandardizing world a vulnerable expensive logistic system is required. There are some methods to ease the logistic problem, e.g. by implementing apparatus for the adaption of the gasturbine for multifuel operation. Particularly the installation of a compact rotating gasifier integrated in the cycle offers promising prospects.
A Method of Performance Evaluation and Equipment Selection for Combined Cycles Used in Cogeneration
Authors: Stephens James O. , Little D. A.
Published: April 2015

The evaluation of the performance of a cogeneration cycle is a complex balance of heat assignments for various portions of the cycle. Selection of the optimum gas turbine, steam turbine, and boiler combination to match the process or district heating requirements requires numerous heat balances.

A method is presented to determine the most fuel-efficient cycle as well as the most efficient combination of equipment to meet the load profile. This system of plotting performance facilitates the selection of a combination that is the most economical for a given electrical and heat load requirement.

Parameters of boiler supplemental firing temperature and equivalent electrical heat rate with steam flow and total fuel consumption for all load conditions are displayed.
A New Generation T56 Turboprop Engine
Authors: McIntire W. L.
Published: April 2015

The focus of the T56 Series IV turboprop engine development program is to improve power and fuel consumption through incorporation of demonstrated technology improvements while retaining the long term durability and cost effective design of the T56 family.

The T56-A-427, the Navy Series IV derivative of the 5000 shp (3728.5 kW) class T56 turboprop engine, resulted from over ten years of technology development via Advanced Turbine Engine Gas Generator (ATEGG), Joint Technology Demonstrator Engine (JTDE), and advanced component programs at Allison Gas Turbine Operations. An example of government and industry cooperation to transfer advanced gas turbine technology is the Air Force Engine Model Derivative Program (EMDP). The initial full-scale demonstration in this program confirmed a 10–1/2% reduction in specific fuel consumption (sfc) and a power growth of 21% in the basic T56 frame. Continued early demonstrations and development by IR&D, Navy funds, and Allison discretionary funds showed a further sfc reduction to 13% and power increase of 28%.

The full-scale development program is now underway to provide production engines in late 1986. Engines will be available for the Grumman E-2 and C-2 aircraft, with follow-on adaptions for Lockheed C-130/L100 and P-3 aircraft, and generator sets for DD 963, DDG 993, CG 47 and DDG 51 warships.
Full Coverage Discrete Hole Wall Cooling: Cooling Effectiveness
Authors: Andrews G. E. , Gupta M. L. , Mkpadi M. C.
Published: April 2015

The development of a test facility for investigating full coverage discrete hole wall cooling for gas turbine combustion chamber wall cooling is described. A low temperature test condition of 750K mainstream temperature and 300K coolant temperature was used to investigate the influence of coolant flow rate at a constant cross flow Mach number. Practical combustion conditions of 2100K combustor temperature and 700K coolant temperature are investigated to establish the validity of applying the low temperature results to practical conditions. For both situations a heat balance programme, taking into account the heat transfer within the wall was used to compute the film heat transfer coefficients. The mixing of the coolant air with the mainstream gases was studied through boundary layer temperature and CO2 profiles. It was shown that entrainment of hot flame gases between the injection holes resulted in a very low ‘adiabatic’ film cooling effectiveness.
Size Effects in Small Radial Turbines
Authors: Scrimshaw K. H. , Williams T. J.
Published: April 2015

The existence of size effects in small radial flow turbines, such as those used in automotive turbocharger units, has been investigated under steady flow conditions. Three geometrically similar turbines (rotor diameters 101.6, 67.73 and 50.8 mm respectively) have been tested and a ‘size’ effect was observed with the dimensionless mass flow and peak efficiency diminishing with a decrease in rotor diameter.

Internal pressure variations were observed in all three turbines which could have a significant influence in relation to blade fatigue failure.
Flow at the Tip of a Forward Curved Centrifugal Fan
Authors: Goulas A. , Mealing B.
Published: April 2015

The velocity profiles, radial and circumferential components, were measured at the tip of a forward curved centrifugal fan. Three sets of measurements are presented. Two at peak efficiency for different rotational speeds and a third at the lower rotational speed and for a reduced flow rate.

A reverse flow region was formed near the hub, and almost in the middle, between pressure and suction sides of the blade. Near the shroud a high velocity region was observed and a low one near the suction side, picture similar to the jet-wake structure found in the literature.

At the lower rotational speed and low flow rate the flow was affected mainly by the system rotation. A “wake” was formed along the suction side of the blade. Increasing the flow rate blade curvature effects became more dominant.

Increasing the rotational speed and for the same flow coefficient the system of two vortices observed in the previous case disappears and a single vortex takes its place. In this case the wake is positioned on the hub.

Corner vortices also affect the main flow by changing the turbulence intensities. A corner vortex observed on the pressure side reduced the turbulence intensities in the region and a wake was formed locally. However, another corner vortex on the suction side caused an increase to the local turbulence intensities and consequently a high local velocity.
Reliability and the Marine Spey
Authors: Healey G. T.
Published: April 2015

Throughout its development the Spey marine propulsion unit has been the subject of a thorough reliability assurance programme in partnership with the Royal Navy. This paper describes the philosophy adopted, the techniques used and discusses the sort of results generated and the wider benefits now becoming apparent of a disciplined approach.
Prediction of Flow in Rotating DISC Systems Using the k-ε Turbulence Model
Authors: Chew J. W.
Published: April 2015

Numerical results are presented for three classes of flow: radial outflow between co-rotating discs, outflow between a stationary and a rotating disc and the flow due to a ‘free’ disc. Comparison of these predictions with other workers’ experimental, analytical and numerical results indicates that the κ-ε model, in its present form, may not be suitable for such flows.