bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of a 6- by 6-Foot Coal-Fired Heater for a CCGT Air Heater
Authors: Russell L. H. , Campbell J.
Published: April 2015

The U.S. Department of Energy is sponsoring a program of research and development on coal-fired heaters to provide heat input to the working fluid of a closed-cycle gas turbine/cogeneration system. One of the fired heater concepts being researched employs the atmospheric pressure fluidized bed coal combustion concept. This paper describes a research oriented atmospheric fluidized bed of 6- by 6-foot plan dimensions that has been designed and is being constructed for utilization during the R&D program. The design rationale is presented, details of the more significant details are described and discussed, and the planned methods for utilizing the 6- by 6-foot AFB as a research tool are presented.
Measurements of Heat Transfer Coefficients on Gas Turbine Components: Part I — Description, Analysis and Experimental Verification of a Technique for Use in Hostile Environments
Authors: Barry B. , Forest A. E. , White A. J.
Published: April 2015

A method of determining local connective heat transfer coefficients around internally cooled components in a hostile flow environment is described. The method involves the measurement of the response of the wall temperature to perturbations in the coolant flow. A companion paper includes results obtained in cascades of turbine aerofoils using refined versions of the method.
Methanol Dissociative Intercooling in Gas Turbines
Authors: Bardon M. F. , Fortin J. A. C.
Published: April 2015

This paper examines the possibility of injecting methanol into the compressor of a gas turbine, then dissociating it to carbon monoxide and hydrogen so as to cool the air and reduce the work of compression, while simultaneously increasing the fuel’s heating value. A theoretical analysis shows that there is a net reduction in compressor work resulting from this dissociative intercooling effect. Furthermore, by means of a computer cycle model, the effects of dissociation on efficiency and work per unit mass of airflow are predicted for both regenerated and unregenerated gas turbines. The effect on optimum pressure ratio is examined and practical difficulties likely to be encountered with such a system are discussed.
Split-Flow Nuclear Gas Turbine Cycle Using Dissociating N2O4
Authors: Kesavan K. , Osterle J. F.
Published: April 2015

An investigation of condensation cycles using dissociating nitrogen tetroxide (N2O4) is presented. Simple cycle arrangement with a gas turbine, a liquid pump and a gas-to-liquid regenerator, and an advanced form known as the “split-flow” cycle are explored over a wide range of turbine inlet temperatures, and subcritical as well as supercritical pressures. The split-flow scheme, using a gas compressor and a gas-to-gas regenerator in addition, shows substantial efficiency gains over the simple cycle through reduced loss of thermodynamic availability in regeneration. Subcritical pressure cycles experience the largest gains, with cycle efficiency improvement of as much as 9 percentage points over the simple cycle.
Development of Ceramic Heat Exchangers for Indirect Fired Gas Turbines
Authors: Bakker W. T. , Kotchick D.
Published: April 2015

Utilizing dirty fuels such as coal in gas turbine engines requires that heat input to the cycle working fluid occur through a heat exchanger. For high cycle efficiencies such a heat exchanger must operate in the 700–1400 KPA, 1100–1200°C (100–200 psi, 2000–2200°F) range. In this temperature range, ceramic heat exchangers are required. Ceramic heat exchangers that can operate in this regime have been under development for several years on a very modest scale. These programs are briefly reviewed. Major material issues are reviewed and the status of each is presented. Mechanical reliability and joining technology have been successfully demonstrated in short term tests. Long-term durability and the manufacturing technology to produce large scale components reproducibly remains to be demonstrated in the future.
Reliability With Electronic Controls
Authors: Bluish J. A. , Thomas R. C.
Published: April 2015

Reliability is a performance parameter that must be addressed within the context of systems engineering as applied to turbine engine controls. Understanding the parameters which control electronic system reliability is necessary in order to perform the cost/benefit analyses required for proper system engineering. Factors imposing special consideration in the requirements for turbine controls are addressed, system design alternatives which affect performance are considered, and parts selection criteria and production efforts which enhance reliability are described.
Control of Self-Excited Flow Oscillations in Vaneless Diffuser of Centrifugal Compression Systems
Authors: Abdelhamid A. N.
Published: April 2015

Experiments were conducted to evaluate the effectiveness of axisymmetric diffuser exit throttle in delaying the occurrence of self-excited flow oscillation in vaneless diffusers. Sharp edge rings were installed at diffuser exit in order to change the exit flow area. Tests were carried out with the rings attached to one or both of the diffuser walls. Steady and unsteady flow measurements were used to determine the flow field in the diffuser at the onset of the flow oscillations. Results showed that the occurrence of flow oscillation was continuously delayed as the diffuser exit flow area was reduced for all these configurations and impeller speeds. Comparison between the performance of the compression system with and without diffuser exit blockage indicated that although large losses occur at high flow rates, the use of diffuser exit rings resulted in overall diffuser performance improvement at low flow rates. Retractable diffuser exit rings would therefore be ideal for centrifugal compression systems with vaneless diffuser.
Performance Characteristics of Indirect-Fired Gas Turbine/Cogeneration Cycles
Authors: Lee J. C.
Published: April 2015

General characteristics equations for cogeneration cycle thermodynamic performance were derived and expressed as functions of the power-to-heat ratio. Based on these equations, design point performance of indirect-fired open-cycle and closed-cycle gas turbine/cogeneration systems were analyzed and compared with those of steam turbine/cogeneration system. Effects of gas turbine pressure ratio and inlet temperature on design point performance were evaluated. Off-design partial load performances of the three cogeneration systems using various control modes were also investigated. Results indicated significant efficiency advantage of the closed-cycle gas turbine/cogeneration system over the others for both design and off-design operations.
Computation of Unsteady Blade Forces in Turbomachines by Means of Potential Flow Theory and by Simulating Viscous Wakes
Authors: Krammer P.
Published: April 2015

This paper describes a new theoretical model which computes two main excitation mechanisms, one based on the potential flow theory and the other explainable by the motion of blades through the wakes of preceding blades. The computation of the potential flow field is based on the assumption of a plane, unsteady, incompressible flow. Fluctuations of circulation caused by an alternating velocity field are taken into account by free vortex paths. Blade surfaces are modeled by a vortex distribution. Viscous wakes are simulated by means of contrarotating vortex rows. Results of the theoretical approach are compared with experimental data measured in axial turbomachines.
Performance Testing of Gas Turbine Compressor Sets
Authors: Cleveland A.
Published: April 2015

The purpose of this paper is to consider, within the overall context of performance testing, the particular application of testing to gas turbine compressor sets for a major gas transmission project. Some of the problems and limitations of the testing methods will be reviewed and the results of recent tests discussed. The use of performance tests as a criterion of acceptance prior to shipment to site could result in major cost benefits in remote locations. The additional effort and cost involved in carrying out such tests is amply justified by the assurance of efficiency in operation and may be essential if optimum operation is to be obtained.
Development of Cast Glass-Ceramic Turbine Housings
Authors: Lanning J. G. , Noll D. A.
Published: April 2015

Corning became actively involved with vehicular gas turbine programs in 1952 during the development of a ceramic rotary regenerator core for the Chrysler automotive gas turbine. Material and process development research in this program led to efforts to apply very low thermal expansion, modest strength, sintered glass-ceramic materials to some of the static gas turbine engine components. One early program involved the first stage turbine plenum for the Ford Model 707 industrial gas turbine. Several process/material iterations ultimately led to the development of a glass-ceramic turbine housing for the Ford Motor Company Model 820 ceramic gas turbine. The housing required a sophisticated slip cast process and a special lithium aluminosilicate (LAS) glass-ceramic composition (Corning Code 9458) with a total thermal expansion between room temperature and 1200C of about 700 ppm. This paper reviews this project and indicates some possible directions for future developments. The design concept and application of the glass-ceramic housing to the Ford Model 820 ceramic gas turbine is discussed in an associated ASME paper by Mr. A. F. McLean of Ford Motor Company.
Comparison of Beam and Shell Theories for the Vibrations of Thin Turbomachinery Blades
Authors: Leissa A. W. , Ewing M. S.
Published: April 2015

A great deal of published literature exists which analyzes the free vibrations of turbomachinery blades by means of one-dimensional beam theories. Recently, a more accurate, two-dimensional analysis method has been developed based upon shallow shell theory. The present paper summarizes the two types of theories and makes quantitative comparisons of frequencies obtained by them. Numerical results are presented for cambered and/or twisted blades of uniform thickness. Significant differences between the theories are found to occur, especially for low aspect ratio blades. The causes of these differences are discussed.
Effect of Using Emulsions of High Nitrogen Containing Fuels and Water in a Gas Turbine Combustor on NOx and Other Emissions
Authors: Singh P. P. , Mulik P. R. , Cohn A.
Published: April 2015

A total of four combustion tests studying the response of various water/fuel emulsion rates on NOx emissions have been conducted on: (a) Paraho shale oil, (b) H-Coal© (372–522 K) distillate, (c) No. 2 oil doped with quinoline, (d) H-Coal© (505–616 K) distillate, utilizing a 0.14 m dia gas turbine can-type combustor at base-load conditions. Each test fuel run was proceeded with a base-line fuel run with No. 2 distillate oil. The results indicate that the effectiveness of water injection to reduce NOx decreased rapidly with an increase in the fuel-bound nitrogen (FBN) content of the test fuels. The smoke number, in general, decreased with increased water injection, while carbon monoxide and unburned hydrocarbons increased at high water/fuel flow rates.
The Design and Test of Air-Cooled Blading for an Industrial Gas Turbine
Authors: Hannis J. M. , Smith M. K. D.
Published: April 2015

The design and testing of a cooled high pressure turbine stage to provide advance information for the Ruston Tornado 6MW industrial gas turbine is described. The cooled stage was designed to replace an existing uncooled stage in a current Ruston gas turbine to allow development testing under actual engine conditions. The instrumentation techniques used on the development engine, including infrared pyrometry, are discussed and results of the tests covering nozzle vane and rotor blade cooling under steady state and transient conditions and engine performance are presented and compared with the design predictions.
Transient Vibration of High Speed Lightweight Rotor due to Sudden Imbalance
Authors: Sakata M. , Aiba T. , Ohnabe H.
Published: April 2015

In the field of rotor dynamics, increased attention is being given to the transient response analysis of rotor, since the effects of impact loading and vibrations of rotor arising from blade loss can be studied by a time transient solution of the rotor system. As recent trends in rotating machinery have been directed towards light-weight, high-speed flexible rotors, the effect of flexibility on transient response analysis is becoming of increasing importance. In the present paper, a transient vibration analysis is carried out on a flexible disc-flexible shaft system or rigid disc-flexible shaft system subjected to a sudden imbalance that is assumed to represent the effect of blade loss. To solve the basic equation governing a rotating flexible disc the Galerkin’s method is used, and the equation of motion of the rotor system is numerically solved by employing the Runge-Kutta-Gill’s method. Experiments were conducted on a model rotor having a blade loss simulator; the shaft vibrations were also measured. The validity of the analytical results was demonstrated by comparison with the experimental results.
Application of a Navier-Stokes Analysis to Transonic Cascade Flow Fields
Authors: Shamroth S. J. , McDonald H. , Briley W. R.
Published: April 2015

A numerical solution procedure for the ensemble-averaged compressible time-dependent Navier-Stokes equations is applied to the transonic cascade flow field. The equations are solved by the consistently split linearized block implicit (LBI) method of Briley and McDonald. Boundary conditions are set so as to specify upstream total pressure and downstream static pressure. Turbulence is modeled by a mixing length model. Predictions are made for flow through a Jose Sanz controlled diffusion cascade and the method yields converged solutions within a relatively small number of time steps (≈ 150). Although to date comparisons with data have not been made, the results show the expected cascade flow field features.
Next Generation Turboprop Gearboxes
Authors: McIntire W. L. , Wagner D. A.
Published: April 2015

A new generation of fuel-efficient turboprop propulsion systems is under consideration now that fuel is a significant portion of the direct operating cost of aircraft. Systems in the 5000- to 15,000-hp (3730- to 11,185-kW) range that use conventional propellers or the new propfan are being studied. Reduction gearing for this next generation of turboprops is of significant interest due to new requirements for cruise speed life, and reliability. Detroit Diesel Allison’s past experience with the T56 family of turboprop reduction gearboxes is recounted. Probable requirements of the next generation of reduction gearboxes are discussed since new requirements for gearboxes combined with past experience should determine the profile of the next generation of gearboxes. A discussion of gearbox general arrangement and its impact on airframe installation is included, along with comments on reduction ratio, gear arrangement, accessory drives, reliability goals, and probable technology needs.
Royal Naval Experience With the Operation of Gas Turbines at Sea
Authors: Baller R. A.
Published: April 2015

The Tyne and Olympus gas turbines have been in service in ships of the Royal Navy for over 8 years. Their introduction, which was a radical change from the steam plants which had powered virtually all major RN warships for over half a century, was accompanied by many changes in the demands placed on ship’s engineers. This paper describes the advantages and disadvantages to the operators which have accompanied this change both in the day to day running and under simulated action damage conditions. While this new means of propulsion has brought new problems in its wake it has proved extremely flexible, reliable and easy to operate, and has virtually eliminated nostalgia for the days of steam.
Ceramic Components for Automotive and Heavy Duty Turbine Engines: CATE and AGT 100
Authors: Helms H. E. , Byrd J. A.
Published: April 2015

Detroit Diesel Allison is actively applying advanced ceramic materials to components in gas turbine engines. Silicon carbide, silicon nitride, aluminum silicate, lithium aluminum silicate, and mullite are materials being used in various components in both the DDA GT 404-4 and AGT 100 engines. Approximately 9400 hr of ceramic component operating time in the GT 404 engine has been accumulated, and design, component processing, proof testing, and engine testing experience have begun to show the applicability of ceramic materials in production engines. Material variability, processing procedures, strength characterization, and nondestructive evaluations are emerging as critical but controllable factors. Ceramic components offer the potential of significant fuel consumption improvements in gas turbine engines for vehicles and other applications.
The Main Propulsion System of HMS Invincible, the Royal Navy’s New Aircraft Carrier
Authors: Ridley P. W. W.
Published: April 2015

The aircraft carrier HMS Invincible is the largest Royal Naval warship for over 20 years. Her 2-shaft main propulsion system employs four Olympus gas turbines in a COGAG formation driving through reversing gearboxes. The paper discusses the installation and summarises the first year’s running experience at sea, which has demonstrated the success of the propulsion machinery design.
Rotating Stall Measurements in the Vaneless Diffuser of a Radial Flow Compressor
Authors: Ligrani P. M. , Van Den Braembussche R. , Roustan M.
Published: April 2015

Results from an experimental study of flow behavior at the inlet of a vaneless diffuser of a centrifugal compressor are presented. Hot-film measurements and measurement results from a crossed hot-wire probe are discussed for operating points having inlet flow coefficients ranging from 0.006 to 0.019 at different Reynolds numbers. Instantaneous, time-averaged, and phase-averaged absolute velocity and flow angle at the diffuser inlet are deduced from the hot-wire signals after correction for mean density variations. These results show how flow behavior varies in stable, rotating stall and surge regimes of compressor operation. The critical flow angle at the onset of rotating stall shows agreement with other measurements confirming the importance of diffuser inlet width and diffuser inlet flow angle on the onset of rotating stall in vaneless diffusers.
Comparison of Interferometric Measurements and Computed Flow Around a Wedge Profile in the Transonic Region
Authors: Bryanston-Cross P. J. , Denton J. D.
Published: April 2015

Numerical solutions to turbomachinery flows have increased in both complexity and accuracy. Conventional measurement techniques cannot always adequately test the detailed solutions available. Holographic interferometry can provide such data and is of particular value in the mainstream region of a two-dimensional flow. The transonic flow around a wedge profile has been used to produce examples of several features of current interest. On the wedge surface a strong leading edge shock is seen followed by a Prandtl-Meyer expansion. On the tunnel sidewall the flow first experiences an expansion and then a boundary layer separation. The flow around the wedge has been calculated using an inviscid time marching program. It is shown that by making simple changes to the geometric data used by the program a good agreement can be obtained despite the presence of a separated flow region.
A Quasi-Three-Dimensional Finite Element Solution for Steady Compressible Flow Through Turbomachines
Authors: Ücer A. S. , Yeġen İ. , Durmaz T.
Published: April 2015

A quasi-three-dimensional solution method is presented for subsonic flows through turbomachines of arbitrary geometry. Principal equations are based on Wu’s formulation of flow on blade-to-blade and hub-to-shroud surfaces, modified such that the same hub-to-shroud principal equation is used for all types of stream surfaces. Blade-to-blade surfaces are assumed to be surfaces of revolution. A stream function is used as the field variable. The problem is solved by finite element method. An iterative solution is used to find the quasi-three-dimensional solution. Solutions at hub, tip and mid height blade-to-blade surfaces are used to construct a mean hub-to-shroud surface and vice versa, until convergence is obtained. Results indicate that the developed technique is satisfactory for predicting the flow through turbomachine blades.
Plasma and Detonation Gun Ceramic and Cermet Coatings in Gas Turbine Engines
Authors: Gill B. , Quets J. M. , Taylor T. A. , Tucker R. C.
Published: April 2015

Plasma and detonation gun coatings of ceramic and cermet materials have achieved widespread application throughout gas turbine engines, and their use continues to grow. The coatings are used in increasingly demanding environments, thus successful utilization requires a thorough understanding of their structure/property relationships and close control of the parameters of deposition. The areas of application within the engine can be roughly separated into low and high temperature regimes. At low temperature, impact/fretting wear, erosion resistance, gas path seals, and various seals and bearings are of concern. Each area requires one or more coating types to satisfy the specific requirements of a given engine. The most common coating types include tungsten carbide-cobalt, alumina, chromium carbide-nickel chromium, a new family of cobalt-base alloys with alumina or chromia dispersions, and magnesium zirconate or stabilized zirconia. The characteristics of major significance of these coatings and their applications will be discussed.
Thermal Decomposition of Aviation Fuel
Authors: Peat A. E.
Published: April 2015

Thermal stressing of aviation fuels can promote the formation of fuel insoluble compounds. Their presence within the fuel system is troublesome to aviation gas turbine manufacturers as they can adversely affect engine performance. To study this phenomenon an experimental program based on a fuel rig capable of reproducing relevant engine conditions and featuring an instrumented replica fuel injector feed arm was devised. The initial objectives are to rate quantitatively the effects of bulk fuel and metal temperatures, fuel flow rates and fuel types on the production of fuel insoluble matter, both deposited and suspended. This report presents the initial results which indicate a relationship between the weight of “tube” carbon deposits and a function of “tube” metal temperature and fuel velocity. Further, this approach could provide the much interface between the engine and laboratory test results.
Progress in the Development of Energy Efficient Engine Components
Authors: Bucy R. W.
Published: April 2015

The NASA-sponsored General Electric Energy Efficient Engine (E3) Program has progressed through development tests of all major components. Results of these component tests are summarized. Major technical features of each of the components are described and test results are compared with design goals. Major emphasis is placed on the high pressure compressor, which is designed for a 23:1 pressure ratio. This advanced technology compressor design completed a series of component tests leading to a configuration which is expected to meet all major objectives of the program. The planned Core Engine and Integrated Core/Low Spool (ICLS) tests are described and expected benefits of these system tests are discussed. Integrated system tests of the components are expected to demonstrate fuel saving benefits which exceed the goals of the NASA E3 Program.
Structural Dynamics of Shroudless, Hollow, Fan Blades With Composite In-Lays
Authors: Aiello R. A. , Hirschbein M. S. , Chamis C. C.
Published: April 2015

Structural and dynamic analyses are presented for a shroudless, hollow, titanium fan blade proposed for future use in aircraft turbine engines. The blade was modeled using the Lewis Research Center’s Blade Structural Analysis Computer Program (COBSTRAN). COBSTRAN is an integrated program consisting of mesh generators, composite mechanics, NASTRAN, and pre- and post-processors. Vibration, and impact analyses are presented. The vibration analysis was conducted with COBSTRAN. Results show the effect of the centrifugal force field on frequencies, twist, and blade camber. This program uses the geometric model and modal analysis from the COBSTRAN vibration analysis automatically to determine the gross impact response of the fan blades to bird strikes. The structural performance of this blade is compared to a blade of similar design but with composite in-lays on the outer surface. Results show that the composite in-lays can be selected (designed) to substantially modify the mechanical performance of the shroudless, hollow, fan blade.
In-Plane Inertial Coupling in Tuned and Severely Mistuned Bladed Disks
Authors: Crawley E. F.
Published: April 2015

A model has been developed and verified for blade-disk-shaft coupling in rotors due to the in-plane rigid body modes of the disk. An analytic model has been developed which couples the in-plane rigid body modes of the disk on an elastic shaft with the blade bending modes. Bench resonance tests were carried out on the M.I.T. Compressor Rotor, typical of research rotors with flexible blades and a thick rigid disk. When the rotor was carefully tuned, the structural coupling of the blades by the disks was confined to zero and one nodal diameter modes, whose modal frequencies were greater than the blade cantilever frequency. In the case of the tuned rotor, and in two cases where severe mistuning was intentionally introduced, agreement between the predicted and observed natural frequencies is excellent. The analytic model was then extended to include the effects of constant angular rotation of the disk.
Experience With a New 35,000 HP Gas Turbine in the Process Industry
Authors: Hopkins P. J. G.
Published: April 2015

Two years’ operation of a new high efficiency gas turbine in the process industry are reviewed. Operational problems are detailed, and the inspection procedures and intervals developed are discussed in relation to the needs of the users and equipment vendor.
Sliding Pressure Operation in Combined Cycles
Authors: Polsky M. P.
Published: April 2015

This paper describes various methods of the power plant load control and gives technical comparison between those methods. It is shown that sliding pressure control is more attractive for combined cycles than for conventional boiler fired plants. A simple graphical method to determine combined cycle steam turbine output at various gas turbine loads is proposed. It also shows that the effectiveness of the sliding pressure operation increases with the decrease of gas turbine load.
Regenerated Marine Gas Turbines: Part II — Regenerator Technology and Heat Exchanger Sizing
Authors: Watts J. W. , Bowen T. L.
Published: April 2015

Analytical studies are currently being conducted by the David Taylor Naval Ship R&D Center to assess the suitability of regenerative-cycle and intercooled, regenerative-cycle gas turbines for naval applications. This paper is the second part of a two-part paper which discusses results of initial investigations to identify attractive engine concepts based on existing turbomachinery and to consider the regenerator technology required to develop these engine concepts. Part I of the paper analyzed existing and next generation engines for performance improvement. Part II includes: definitions of performance parameters such as effectiveness and pressure drop, a discussion of regenerator types, and comments on regenerator materials, life, maintenance, and fouling. Tradeoffs between size, weight, and performance of plate-fin recuperators are examined using two of the hypothetical engines from Part I as examples. Results are compared for several different recuperator matrices to illustrate the effects of air-side and gas-side fin density and plate spacing on size, weight, and performance.
The Impact of Microprocessors on Rotating Machinery Data Acquisition and Diagnostic Information Systems
Authors: Harker R. G. , Cronquist W. E.
Published: April 2015

Traditionally, vibration monitoring and protection equipment has been totally separate from the diagnostic and data acquisition equipment as used for rotating machinery information systems. Application oriented utilization of multiple microprocessors in a distributed processing system can virtually eliminate this artificial barrier. The design philosophy, block diagram, and operating results obtained from actual field-installed units will be presented. In addition, its use with a central Host Processor computer based total plant rotating machinery information system will be discussed.
Ceramic Thermal Barrier Coatings for Turbine Engine Components
Authors: Duvall D. S. , Ruckle D. L.
Published: April 2015

The durability of plasma sprayed ceramic thermal barrier coatings subjected to cyclic thermal environments has been improved substantially by improving the strain tolerance of the ceramic structure and also by controlling the substrate temperature during the application of the coating. Improved strain tolerance was achieved by using ceramic structures with increased porosity, microcracking or segmentation. Plasma spraying on a controlled-temperature substrate also has been shown to improve durability by reducing harmful residual stresses. The most promising of the strain tolerant ceramic coatings have survived up to 6000 cycles of engine endurance testing with no coating or vane platform damage. In side-by-side engine tests, thermal barrier coatings have shown that they greatly reduce platform distress compared to conventionally coated vanes in addition to permitting reductions in cooling air and attendant increases in engine efficiency.
The 125 MW Combined Cycle Power Plant “Korneuburg-B”: Design Features, Plant Performance and Operating Experience
Authors: Czermak H. , Wunsch A.
Published: April 2015

In January 1980 NEWAG, an Austrian utility, commissioned a natural gas fired 125 MW combined cycle unit at Korneuburg near Vienna. The plant has some interesting characteristics which have led to an exceptionally high net efficiency during the first 19 months of operation though the plant is started twice daily within 30 minutes and is used for medium/peak load shaving. A detailed description of the fully automized plant systems, their main components, the design and test data, as well as the operational experience are given in this paper. The Korneuburg plant can be considered as an example of the present state of the art of power plant engineering.
Small Engine Inlet Air Particle Separator Technology
Authors: Morrow H. L. , Cale D. B.
Published: April 2015

The initial deployment of gas turbine engine powered Army helicopters was accomplished with no consideration of inlet protection. Early operational experience did not reveal any serious problems associated with sand and dust erosion. During the formulation and operational testing of the airmobile concept, engine deterioration and damage due to sand and dust erosion became a serious operational problem and subsequently a series of major research and development (R&D) programs were initiated to solve the problem. These R&D programs included numerous approaches: (1) investigation of materials/coatings, (2) definition and control of environment, (3) definition of engine susceptibility, (4) development of separator kits, and (5) development of integral particle separators. This paper summarizes 15 years of US Army R&D activities pertaining to sand and dust erosion of helicopter gas turbine engines which have led to the current requirement for integral inlet particle separators.
Some Environmental Considerations in Large Gas Turbine Power Stations
Authors: Collotte P. , DeFlandre M.
Published: April 2015

The increasing need to locate gas turbine power stations in the vicinity of residential sections forces the manufacturer to meet stringent noise abatement requirements which seems to get stricter as time progresses. This paper identifies major sources of noise emitted by gas turbine power stations, analyzes the techniques to reduce the emission and to suppress the propagation of this noise, describes practical approaches and reports measurements performed on medium and large size installations. Finally the economics of adequate silencing is considered.
The Turbulent Boundary Layer on an Axial Compressor Blade
Authors: Walker G. J.
Published: April 2015

Time-mean flow measurements of turbulent boundary layer development on the convex surface of an outlet stator blade in a single-stage axial compressor are presented. There is no evidence of logarithmic wall similarity at blade chord Reynolds numbers from 3 × 104 to 2 × 105, and its absence appears due to the combined effects of low Reynolds number, large positive pressure gradient and rapidly changing boundary conditions. Conventional skin friction laws compare very poorly with experiment. The performance of local equilibrium and entrainment-type calculation methods is examined and serious errors are found to develop at blade Reynolds numbers below 105. The best results are obtained from a lag-entrainment method of Green, Weeks and Brooman, which can be recommended for predicting axial turbomachine blade boundary layers at moderate Reynolds number.
Development and Application of Dabber Gas Tungsten Arc Welding for Repair of Aircraft Engine, Seal Teeth
Authors: Rudy J. F.
Published: April 2015

Dabber TIG welding can be defined as a modification of an automatic TIG welding system. Modifications, both mechanical and electronic, combine to cause an intermittent filler wire feed to the molten weld puddle. This interrupted action allows for momentary cooling of the weld puddle. Energy input, as heat, for a given time span is reduced by this action. In addition the interruption allows solidification of the puddle with resultant narrow, uniform bead. This weld mode is characterized by shallow heat affected zones and precise weld build up configurations. This paper describes the application of this procedure to Gas Turbine Seals.
Experience With Large Gas Turbine Combustion Chambers
Authors: Lienert A. , Schmoch O.
Published: April 2015

Large gas turbine combustion chambers, being arranged outside of the unit, exhibit quite a lot of advantages with respect to combustion. Moreover, they are characterized by a long life of all components. Thus, in case of such gas turbine units the maintenance and inspection intervals are relatively large being not determined by the combustion chamber or combustion chamber components. There are not many failures. They may easily be recognized at their initial stage and can be eliminated quickly as the inside is accessible via a manhole. This in turn has a positive effect on overall maintenance and service cost. Besides, this easy accessibility allows for a direct examination of the turbine inner casing and the first turbine stages in case of maintenanced works. Experiences are based on the operation of more than 100 gas turbines of such a kind, whereby several have been run at peak load with more than 5000 starts, others at base load with more than 100,000 operating hours.
Stand-By Forced Draft Fan Versus Supercharging Gas Turbines for Pre-Combustion Air to Fully Fired Boilers in Combined Cycles
Authors: Stephens J. O.
Published: April 2015

The purpose of this paper is to analyze the technical features of two different arrangements of supplying fresh air to the boilers in fully fired combined cycles for continuous boiler operation using a forced draft fan when the gas turbine is out of service. The first case is the conventional stand-by forced draft fan and the second is the supercharged fan arrangement. Two methods of separating the cycles are reviewed in detail: a) Cold start-up of system. b) While operating in the combined cycle mode, the gas turbine trips. c) While operating the boiler with fresh air firing the gas turbine is started for combined cycle operation. d) Normal shut down of the gas turbine. e) While operating in the combined cycle mode, the boiler trips. This paper presents the results of a study of a 350-MW combined cycle power plant for Alsands Energy Ltd., of Calgary, Alberta, Canada.
Application of RSR Powder Metals to Vehicular Gas Turbine Engines
Authors: Cox A. R. , Billman L. S.
Published: April 2015

Rapid solidification powder metallurgy alloy development is evolving new materials which have potential benefit to vehicular gas turbine components. Aluminum alloys with higher temperature capability for compressors, iron alloys with better properties for recuperators, and nickel alloys capable of sustaining higher stresses and temperatures for turbines are examples of the possibilities from this new technology. Additionally, the direction of these developments has taken a course whereby reduction in concentration of strategically limited elements which are now used in engine materials appears feasible.
Liquid Particle Dynamics and Rate of Evaporation in the Rotating Field of Centrifugal Compressors
Authors: Pinkus O.
Published: April 2015

A model is presented which consists of injecting a liquid coolant into the gas or superheated vapor of centrifugal compressors via slots in the rotating blades. The aim of the injection is minimization of required compression work. The three-dimensional analysis determines the relative velocities and trajectories of the liquid particles, and their rate of vaporization as a function of the prevailing flow field and inlet conditions. Inertia, viscous drag, centrifugal and Coriolis forces are all included. The analysis rests on the assumption of low volumetric liquid/gas ratios so that the aerodynamics of the flow is not appreciably disturbed. The computer-obtained results show that for optimum conditions, and to avoid collision with the blades, it is desirable that injection occur at the suction side of the blades and close to the hub, that low rather than high initial particle velocities are preferred, and that small droplet sizes are required both to avoid blade erosion and to assure the highest rate of vaporization.
Parametric Analysis of Combined Gas-Steam Cycles
Authors: Cerri G.
Published: April 2015

Combined gas-steam cycles have been analyzed from the thermodynamic point of view. Suitable thermodynamics indices — explained in Appendix A — have been utilized. The parameters that most influence efficiency have been singled out and their ranges of variability have been specified. Calculations have been carried out — see Appendix B — taking into account the state of the art for gas turbines and the usual values for the quantities of steam cycles. The results are given. The maximal gas turbine temperature has been varied between 800°C and 1400°C. The gas turbine pressure ratio has been analyzed in the range of 2–24. Afterburning has also been taken into consideration. Maximal efficiency curves and the corresponding specific work curves (referred to the compressed air) related to the parameters of the analysis are given and discussed.
The U.S. Navy Racer Development Program
Authors: Marron H. Douglas
Published: April 2015

The marine gas turbine initially became a predominate force for U.S. Navy surface combatant main propulsion upon selection of the General Electric LM2500 to power the SPRUANCE Class destroyers (DD 963) in 19691. There had been numerous earlier applications of gas turbine engines on hydrofoils, minesweepers, and auxiliary power supply units, all of which contributed to a major surface Navy commitment to gas turbines in 1969. By 1985, approximately 50 percent of the U.S. Navy’s non-nuclear combatant ships will be powered by gas turbines and it is expected that this may approach 100 percent by the year 2000. In 1975, this was recognized as a possibility as was the realization that the U.S. Navy’s fossil fuel supplies could now be disrupted by outside influences. Prior to this time, the U.S. Navy’s surface combatant main propulsion research and development was clearly being driven towards developing a “family” of simple cycle marine gas turbines varying in size from 1,000 to 50,000 hp. High efficiency and energy savings, although considered, were not driving factors in the overall design and development of these engines. Studies were initiated in 1975 to determine if a major improvement could be made in fossil fuel main propulsion plants for surface combatants while retaining the inherent advantages of the marine gas turbine. Twenty-six different candidate configurations were examined in 1975 including simple cycle, recuperated, closed cycle, and combined cycle gas turbine plants. In the final analysis, a Combined Gas and Steam Cycle (COGAS) power plant was chosen for development based on its superior life-cycle cost advantage and the commercial market potential it offered. The General Electric main propulsion LM2500 was chosen as the best candidate gas turbine for efficiency improvement based on its current production schedule, future applications potential, and minimum logistic support impact. Approval to proceed with development was received in July 1977, at which time a technology program was launched to establish a sound baseline for full-scale prototype development.
Full Load Operation of a Gas Turbine Combustor With Acoustically Controlled Dilution-Air Mixing
Authors: Vermeulen P. J. , Odgers J. , Ramesh V.
Published: April 2015

Previous work (1) presented the test results up to “half-load” conditions for a small tubular combustor of normal design employing acoustic control of the dilution-air flows. It was shown that acoustic modulation of the dilution-air flows can be used to selectively and progressively control the exit plane temperature distribution. In particular, for an already good traverse quality, it is possible to trim the temperature profile. The technique contributes to the design of combustors such that a desired exit plane temperature distribution may be achieved.
Fuel Efficiency Improvements in U.S. Navy Gas Turbine Systems
Authors: Brady Eugene F.
Published: April 2015

Major efforts are currently underway to improve the fuel consumption efficiency of gas turbines for powering of U.S. Navy surface ships. Recent efforts have focused on efficiency improvement by the recovery of waste heat, in system enhancements such as the RACER (Rankine Cycle Energy Recovery) system. More recently, however, consideration is also being given to the use of a recuperator (and possibly an intercooler) to improve basic gas turbine thermal efficiency. Furthermore, a third approach is to improve efficiency by enhancements in basic gas turbine component technology.

In this paper, current activity and progress in each of these three systems concepts are presented. First, the ship design benefits resulting from improved fuel efficiency will be described. Following this, programs in each of the above three categories are presented. This includes a general description of the hardware system, and the major performance characteristics.

Finally, appropriate comparisons of these three approaches are made. These include projected fuel efficiency improvements, and the required ship space and weight. Projected future developments are also described.
Stalled Flow Performance for Axial Compressors: II — Rotating Stall Characteristic
Authors: Koff S. G.
Published: April 2015

This paper describes a study of stalled flow performance of multistage compressors. The study is focused on the performance in rotating stall, in particular, the impact on stall inception and stall recovery. It is argued that the recovery point measured in post-stall compressor tests results from a compression system instability, rather than from an unstable rotating stall flow. If so, recoverability from rotating stall may be improved by altering system parameters. Furthermore, the full-span rotating stall characteristic is extrapolated beyond the measured recovery point. On this basis, the compressor stall point is viewed as a bifurcation, where a change in flow mode exists, perhaps analogous to the critical point in the axial compression of thin shells. An application for the extended rotating stall characteristic is in a model of transient compression system behavior.
Evaluation of the Compression-Intercooled Reheat-Gas-Turbine-Combined Cycle
Authors: Rice Ivan G.
Published: April 2015

Interest in the reheat-gas turbine (RHGT) as a way to improve combined-cycle efficiency is gaining momentum. Compression intercooling makes it possible to readily increase the reheat-gas-turbine cycle-pressure ratio and at the same time increase gas-turbine output; but at the expense of some combined-cycle efficiency and mechanical complexity. This paper presents a thermodynamic analysis of the intercooled cycle and pinpoints the proper intercooling pressure range for minimum combined-cycle-efficiency loss. At the end of the paper two-intercooled reheat-gas-turbine configurations are presented.
The Integrated Gas/Steam Nozzle With Steam Cooling: Part II — Design Considerations
Authors: Rice Ivan G.
Published: April 2015

The integration of multiple steam nozzles with the first-stage annular-gas nozzle to form a binary-flow system in a reheat-gas turbine is presented whereby steam is first used as an internal vane coolant before being expanded and accelerated for work extraction. Steam nozzles are located in “fat-body” type vanes. Trailing-edge impingement followed by reverse-serpentine-flow cooling takes place. Internal trailing-edge-steam nozzles produce either diffusion or shock-wave boundary-layer disturbance inside the trailing edge to enhance heat transfer. Externally, steam blanketing reduces nozzle-profile loss and improves film cooling effectiveness by reducing the surface viscosity and secondly by controlling suction-side aft-shock-wave development. A new vane shape coupled with a gas-turning-combustor system is suggested to improve vane-film cooling effectiveness further.
An Approach to Selecting Gas Turbine Engine Ratings for Fixed Wing Airplanes
Authors: Agrawal R. K.
Published: April 2015

This paper presents an approach to selecting the various ratings for Gas Turbine engines in the fixed wing airplane application. The approach followed is first to estimate the minimum airplane power demands to pass its certification requirements under worst operating conditions. These power demands are then checked against those available from the engine within its certification requirements. Meaningful trade off studies, involving both the airplane and engine designers, can thus be conducted fairly early on in the airplane/engine design cycle to arrive at engine rating’s which will best suit both the vehicle and its power plant within their respective certification constraints.
Designing for Durability in Fighter Engines
Authors: Koff Bernard L.
Published: April 2015

Aircraft fighter engine design is a tradeoff between performance, reliability/durability, weight, and cost. The performance including operability and, more recently, survivability, can largely be determined early in the development program. “Shake and bake” component testing followed by Accelerated Mission Testing (AMT) can go a long way in the development of overall reliability. Engine weight and manufacturing cost can also be determined up front with reasonable certainty. However, durability or life is not readily determined during development and remains a promise to be designed into the engine to achieve the life requirements and reasonable cost of ownership. It can be argued that durability, heavily dependent on the mission duty cycle, is also closely linked to reliability, maintainability, and safety. Designing for durability includes “starting off on the right track” with the initial configuration, the selection of reliable and dependable damage tolerant materials and manufacturing processes, a rigorous structural analyses, and overall attention to detail. This paper describes an art and science “lessons learned” approach developed during the past 25 years to accommodate rapid throttle maneuver transients encountered in the aircraft fighter engines.