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IN THIS VOLUME


General

1972;():V001T01A004. doi:10.1115/72-GT-4.
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Full-scale front fans were designed and tested with satisfactory results. The flow field in passing through the fans was estimated with a powerful method called streamline-curvature technique, and the first test-program was carried out in equipping the rotor blade row without snubbers (part-span shroud) and the second conducted with them. The detailed analyses of the test results showed that the snubbers had some effect on the operation of a fan stage at all locations within the stage and not only in locations locally near to the snubbers.

Topics: Fans
Commentary by Dr. Valentin Fuster
1972;():V001T01A006. doi:10.1115/72-GT-6.
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A review of conditions necessary for turbine engine icing is presented along with the potential problems caused by engine icing. Methods of protecting the engine against icing are briefly presented and a method of automatic anti-ice operation is proposed.

Topics: Gas turbines , Ice
Commentary by Dr. Valentin Fuster
1972;():V001T01A008. doi:10.1115/72-GT-8.
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An experimental study of aerodynamic damping has been carried out on an axial compressor in which stagger angle, pressure ratio, and relative velocity was varied. The study utilized explosive charges buried in the tip of the blade to provide excitation and found the damping by measuring the log decrement of the vibrations. The blade vibratory mode was pure bending.

Commentary by Dr. Valentin Fuster
1972;():V001T01A009. doi:10.1115/72-GT-9.
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A carbohydrate derivative was designed as a gelling agent for turbine fuel. The gelling agent is effective in reducing fire hazards of the fuel. The chemical and physical properties of the gelling agent are presented. Rheological data of the gelled fuel pertinent to aircraft operation are outlined and discussed.

Topics: Fuels , Turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A010. doi:10.1115/72-GT-10.
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A family of natural gas compressors is designed and developed for application with the Solar Centaur T-3000 gas turbine engine. These compressors are capable of matching the power and speed of the engine over a wide range of compressor suction pressure and flow conditions. Design of these compressors includes analysis of possible aerodynamic configurations, and selection of the mechanical arrangement to best meet the expected installation requirements. Aerodynamic characteristics, bearing and seal performance, impeller integrity, and housing rigidity are all developed in a test program prior to shipment of the first compressors. Follow-up of the first field operation further verifies that the design objectives had been met.

Commentary by Dr. Valentin Fuster
1972;():V001T01A011. doi:10.1115/72-GT-11.
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This paper describes the specific procurement information required from the purchaser and corresponding information required from the gas turbine manufacturer in the various phases of procurement. Through the guidelines presented the preparation of procurement specifications and manufacturer’s response will be facilitated and mutual understanding promoted. In sequence, the paper deals with: (a) the purchaser’s inquiry, (b) the manufacturer’s proposal or bid tendering and (c) required after order information: Specimen data sheets are included to illustrate in detail the material presented. This paper is one of a series of ASME papers which present a Proposed Gas Turbine Procurement Standard.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A012. doi:10.1115/72-GT-12.
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The first three units of the improved industrial 15,000-hp gas generator GT35 were taken into commercial operation during 1970 in a gas compressor station for the Nederlandse Gasunie in Wieringermeer, the Netherlands. This paper gives a description of the equipment and deals with the experience from workshop tests, commissioning and commercial operation.

Commentary by Dr. Valentin Fuster
1972;():V001T01A013. doi:10.1115/72-GT-13.
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This paper briefly reviews the development of specifications for fuels which can be burned in marinized aircraft and industrial-type gas turbines for ship propulsion and auxiliary power. It then considers the types of fuels — gas to residual — which will be available on a worldwide basis during the ‘70s, logistics involved, and potential problems that can develop in handling and firing them.

Commentary by Dr. Valentin Fuster
1972;():V001T01A014. doi:10.1115/72-GT-14.
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The continual demands for improved technology aircraft propulsion systems require refined wind tunnel model testing techniques to more closely simulate full-scale performance. Toward this end a test program was conducted using a subsonic powered nacelle model to statistically investigate the effect of key geometrical variables on nacelle pressure drag. A comparison of test results with analytical prediction techniques is presented, along with the effects of various design parameters on drag. The advantage of powered nacelle models for obtaining subsonic nacelle pressure drag information is also included.

Commentary by Dr. Valentin Fuster
1972;():V001T01A019. doi:10.1115/72-GT-19.
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The high strengths now attainable with hot pressed silicon nitride combined with its good oxidation and thermal shock resistance make it a most promising candidate for advanced gas turbine hot components. This form of silicon nitride has flexural strengths of 110,000 psi at room temperature and 60,000 psi at 1200 C. A recent experimental version of the system has exhibited room temperature strength of 145,000 psi and elevated temperature (1200 C) strength of 100,000 psi. This may be the highest strength reported on any material at this elevated temperature.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A020. doi:10.1115/72-GT-20.
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Two unique ceramic materials offer the gas turbine designer the opportunity to substitute uncooled high temperature components for the presently cooled metal and alloy ones. Recrystallized silicon carbide made by a casting process and reaction bonded silicon nitride shaped by a simple machining process before firing, offer not only high temperature materials capable of living in the gas turbine environment, but also an intricacy of shape consistent with combustor, shroud and associated high temperature component needs. Silicon carbide’s 3200 F capability and its thermal shock resistance makes it a sound choice; silicon nitride’s low expansion coefficient, thermal shock resistance, and 2900 F capability make it a material of real merit. The properties of these materials are discussed in detail along with potential areas of application and design capabilities.

Commentary by Dr. Valentin Fuster
1972;():V001T01A022. doi:10.1115/72-GT-23.
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This paper is a summary of the federal legislation through October 1971 pertaining to environmental controls for air, water, and noise. Only that legislation having an impact on gas turbine, steam turbine, and combined gas turbine–steam turbine power generating equipment is considered. Environmental regulations are changing rapidly and must be followed closely for the next few years. This paper is intended to be the first of a series of papers on the subject.

Commentary by Dr. Valentin Fuster
1972;():V001T01A023. doi:10.1115/72-GT-24.
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The LM2500 is a Marine and Industrial gas turbine derived from the TF39 engine built for the USAF C5A transport. As such it operates as a core engine without the high bypass fan supercharging effect. The combustor for the LM2500 is an annular combustor developed for use with marine and industrial fuels including natural gas and heavy distillates. This paper relates the development of this combustor including some of the design criteria, the fuel properties and some of the combustor performance results such as exit gas temperature patterns, ignition, pressure loss, and efficiency. The engine combustor operates with a clear smokeless stack utilizing heavy distillate fuels and is free of carbon formation. Fuel properties and atomization properties are related to exhaust smoke. Investigations have included a wide range of fuels and several fuel injector designs. The engine has operated in GTS Adm. Wm. M. Callaghan for a total of more than 10,000 hrs with no combustor problems, smoke, carbon, life or otherwise.

Commentary by Dr. Valentin Fuster
1972;():V001T01A024. doi:10.1115/72-GT-25.
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This paper is directed to the modification of jet fuels to reduce the inherent fire hazard of such fuels. Some of the problems and compromises involved in this development program are discussed. The theoretical concept pursued is outlined and some of the physical properties of the final compromise modified fuel are shown.

Topics: Jet fuels , Fire , Aircraft , Hazards
Commentary by Dr. Valentin Fuster
1972;():V001T01A025. doi:10.1115/72-GT-26.
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When dealing with axisymmetric rotating flow through turbomachines of a given geometry, the existence of discontinuities, due to incidence at the leading edges of the blades, has to be accepted as a logical consequence of axisymmetry. By introducing special conditions resulting from dynamical equilibrium considerations, a relaxation method has been enabled to cope with these discontinuities.

Commentary by Dr. Valentin Fuster
1972;():V001T01A026. doi:10.1115/72-GT-27.
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Safety fuels such as emulsified and gelled fuels have been studied over the past several years as one means for reducing the post-crash fire hazard associated with aircraft accidents. However, through the work described herein, only recently has a quantitative evaluation been made to characterize the safety performance of these fuels. The safety performance evaluation program described in this paper includes an initial series of screening tests designed to obtain the characteristics of safe fuels in the aircraft crash environment. The authenticity of the screening tests relative to the full-scale crash environment was evaluated through a second series of experiments designed to simulate a full-scale aircraft crash environment. A crashworthiness evaluation criterion was established in terms of an “ignition susceptibility parameter” to quantitize the relative safety performance of different fuels. The conclusions of this research clearly show that significant savings in lives and equipment can be realized if safe fuels which perform within the non-hazardous envelope of the ignition susceptibility parameter are operationally incorporated in present-day aircraft.

Commentary by Dr. Valentin Fuster
1972;():V001T01A027. doi:10.1115/72-GT-28.
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The Federal Aviation Administration is engaged in programs to reduce the probability and/or severity of fire in commercial jet transport aircraft that are involved in ground crash situations. One of the approaches being taken is the development of a modified aviation turbine fuel that will provide a significant reduction in the crash-fire hazard. The modified fuels program, initiated in 1964, brought to light that under small-scale simulated crash conditions the fire reduction benefits of fuel thickeners result from their ability to physically bind the fuel and thus reduce the rate of vaporization and the exposed surface area available to support a fire. Dozens of thickened fuel candidates have undergone cursory screening, and a small percentage of those that looked promising have been subjected to a crash fire rating system designed to provide relative values of candidate fuels. Chemical and physical studies, completed in 1971, on two of the leading fuel candidates greatly improved their fluidic property with no adverse affect on their fire retardative properties, while in mist form. The agency’s plans, to demonstrate the safe operation of aircraft using a modified fuel and to demonstrate the improvement in crash fire safety by conducting full-scale crash tests, are proceeding to take shape due primarily to the continued progress being made by the developers of the gelled fuels.

Topics: Fuels , Turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A028. doi:10.1115/72-GT-29.
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For years, manufacturers and users of rotating machinery have searched for an accurate and easily used shaft power measurement technique. These users wanted a system with characteristics such as non-contact, no field calibration, shaft realignment compensated, adaptable to control and protective functions, plus high component reliability and accuracy. This paper describes such a system.

Commentary by Dr. Valentin Fuster
1972;():V001T01A030. doi:10.1115/72-GT-31.
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A numerical technique is presented for the calculation of shocked flows in compressor cascades. The problem is posed in the time-dependent form and the asymptotic solution at large times provides the solution of the steady physical problem. The solutions exhibit the formation and movement of shocks as the static pressure ratio across the cascade is varied. The resulting inlet and outlet angles and total pressure loss are also shown.

Commentary by Dr. Valentin Fuster
1972;():V001T01A031. doi:10.1115/72-GT-32.
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Because of intense development in the aircraft gas turbine field over the last 30 years, the fixed boundary recuperator has received much less development attention than the turbomachinery, and is still proving to be the nemesis of the small gas turbine design engineer. For operation on cheap fuel, such as natural gas, the simple cycle-engine is the obvious choice, but where more expensive liquid fuels are to be burned, the economics of gas turbine operation can be substantially improved by incorporating an efficient, reliable recuperator. For many industrial, vehicular, marine, and utility applications it can be shown that the gas turbine is a more attractive prime mover than either the diesel engine or steam turbine. For some military applications the fuel logistics situation shows the recuperative gas turbine to be the most effective power plant. For small nuclear Brayton cycle space power systems the recuperator is an essential component for high overall plant efficiency, and hence reduced thermal rejection to the environment. Data are presented to show that utilization of compact efficient heat transfer surfaces developed primarily for aerospace heat exchangers, can result in a substantial reduction in weight and volume, for industrial, vehicular, marine, and nuclear gas turbine recuperators. With the increase in overall efficiency of the recuperative cycle (depending on the level of thermal effectiveness, and the size and type of plant), the cost of the heat exchanger can often be paid for in fuel savings, after only a few hundred hours of operation. Heat exchanger surface geometries and fabrication techniques, together with specific recuperator sizes for different applications, are presented. Design, performance, structural, manufacturing, and economic aspects of compact heat exchanger technology, as applied to the gas turbine, are discussed in detail, together with projected future trends in this field.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A032. doi:10.1115/72-GT-33.
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The use of a regenerative cycle powerplant is a means of improving the part load fuel consumption of gas turbine engines. The use of air-to-gas regenerative systems for high thermal effectiveness and low pressure drop goals, however, can involve a prohibitive increase in engine volume and weight and a severe compromise to engine configuration. This paper describes a lightweight regenerator for a 4000-shp turboshaft engine in which the transfer of heat from the turbine exhaust gas to the compressor discharge air is accomplished by a liquid metal system using NaK as the heat transport fluid. The design of the regenerator system, consisting of an exhaust gas-to-liquid metal heat exchanger, a liquid metal-to-compressor air heat exchanger and a liquid metal rotary induction pump which form the hermetically sealed liquid metal circuit, is presented. Results of analytical studies and information concerning the special manufacturing processes for these system components are described. The results of performance and durability testing of this regenerator system under simulated engine conditions are also presented and compared with predicted performance.

Commentary by Dr. Valentin Fuster
1972;():V001T01A040. doi:10.1115/72-GT-41.
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The hodograph method has been used extensively in France for the computation of turbomachine blade profiles. The work started in 1939 but the industrial development took place during the last decades. This paper presents recent research and the results obtained. The method used in “Association Technique pour la Turbine à Gaz” (ATTAG) and in industry concerns the assimilation of the real fluid to the Chapligin ideal fluid. It permits only calculation of profiles for subsonic flows but provides quite satisfactory predictions for velocities near the critical value. It is easy to use. More complicated developments are undertaken for defining profiles adapted to reversible transonic flows, i.e., without shock. Different methods providing similar results are being studied by several groups in ONERA.

Commentary by Dr. Valentin Fuster
1972;():V001T01A041. doi:10.1115/72-GT-42.
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The high efficiencies of small radial turbines have led to their application in space power systems and numerous APU and shaft power engines. Experimental and analytical work associated with these systems has included examination of blade shroud clearance, blade loading, and exit diffuser design. Results indicate high efficiency over a wide range of specific speed and also insensitivity to clearance and blade loading in the radial part of the rotor. The exit diffuser investigation indicated that a conventional conical outer wall may not provide the velocity variation consistent with minimum overall diffuser loss. A list of recently published NASA radial turbine reports is included.

Topics: Turbines , NASA
Commentary by Dr. Valentin Fuster
1972;():V001T01A042. doi:10.1115/72-GT-43.
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This paper describes a method for determining the development of the losses downstream of two-dimensional transonic turbine cascades. The distance between the cascade exit and the plane downstream at which the flow has become nearly uniform is evaluated by theory and experiment. The problems associated with measuring local flow properties in the nonuniform supersonic flow field behind transonic turbine cascades are discussed and analyzed.

Commentary by Dr. Valentin Fuster
1972;():V001T01A043. doi:10.1115/72-GT-44.
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Facets of safety of operating personnel, the public and equipment are presented in this paper which is one of a series covering all subjects of the proposed gas turbine procurement standard. Information is furnished to provide guidance in the preparation of gas turbine purchase specifications. Comments and suggestions are welcomed by the authors in order to improve this material and produce a more useful standard.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A044. doi:10.1115/72-GT-45.
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This paper discusses the design study of a new gas turbine cycle for marine use. General characteristics of the cycle are investigated by simple calculations and a design study of a 40,000-hp power plant is presented. Evaluating this power system, an 80,000-hp high-speed container ship is taken as an example and is compared with diesel engine propulsion.

Commentary by Dr. Valentin Fuster
1972;():V001T01A045. doi:10.1115/72-GT-46.
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A method for determining the performance of a two-dimensional turbine cascade with boundary layer injection is developed using existing incompressible boundary layer approximate solutions with a new formulation for the injection. The overall cascade loss includes friction and wake mixing losses. The results of the analysis are compared with experimentally obtained data as a check of the validity of the new analytical method.

Commentary by Dr. Valentin Fuster
1972;():V001T01A046. doi:10.1115/72-GT-47.
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This paper deals with the flow through cascades, which have a supersonic flow up- and downstream. A theoretical method is described to calculate, under certain conditions, the flow quantities up- and downstream of and within the cascade and to determine the pressure distribution on the blades. The method is compared with experimental results, carried out in the cascade wind tunnel of the Aero dynamische Versuchsanstalt Göttingen (AVA), Germany.

Commentary by Dr. Valentin Fuster
1972;():V001T01A047. doi:10.1115/72-GT-48.
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Blades of axial flow compressors are often roughened by corrosion or erosion. There is only scant information about the influence of this roughening on the boundary layers of the blades and thereby on the compressor efficiency. To obtain detailed information for calculating the efficiency drop due to the roughness, experimental investigations with an enlarged cascade have been executed. The results enabled to develop new formulas for a modified friction coefficient in the laminar region and for the laminar-turbulent transition and the separation points of the boundary layer. Thus, together with the Truckenbrodt theory, it was possible, to get a good reproduction of the experimental results.

Commentary by Dr. Valentin Fuster
1972;():V001T01A048. doi:10.1115/72-GT-49.
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In this paper the supersonic exit flow field of a two-dimensional cascade is described. Different flow configurations at axial subsonic and supersonic velocities are discussed in detail and calculation methods are presented. The range of possible cascade operation and its dependency of back pressure is evaluated. It is shown that the exit flow field of a double infinite cascade can be simulated behind a semi-infinite cascade.

Topics: Flow (Dynamics)
Commentary by Dr. Valentin Fuster
1972;():V001T01A049. doi:10.1115/72-GT-50.
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The flow in the rotors of three radial turbines, of differing peak efficiency, is analyzed using a streamline curvature method. The turbine of greatest efficiency is analyzed at both on- and off-design conditions; the other two turbines at the design point only. Comparison is made between the predictions of the calculation and the experimental determination of two features of the flow — the shroud static pressure distribution and the outlet velocity profile. Fair agreement with the shroud pressure is obtained at on-design conditions, but correlation with the exit velocity distribution is poor. Some improvement in the calculation of the exit profile is achieved when the analysis is modifed so as to allow for the experimentally observed angle of deviation at the blade trailing edge. Consideration is given to the ability of the analytical method to discriminate between turbines which prove experimentally to have high or low peak efficiency.

Commentary by Dr. Valentin Fuster
1972;():V001T01A050. doi:10.1115/72-GT-51.
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Experiments have been performed which indicate the potential of metal-fiber reinforced-ceramic matrix composites for use as a high temperature structural matrix. The results of this work reveal that metal-fiber reinforced ceramics obey compostie theory, and that after cracks occur in the matrix, a pseudo-ductility can be introduced into the composite. This toughness can be predicted from equations of work required to pull the fibers through the matrix. The relationship between strength, toughness, and crack depths, are dependent on the inter-facial bond between the fibers and matrix as well as fiber diameter and length. Based on the results of these experiments, multicomponent materials with superior resistance to failure from oxidation, thermal shock, and high mechanical stresses in air above 2400 F can be postulated. These materials have potential for use as gas turbine engine vanes.

Commentary by Dr. Valentin Fuster
1972;():V001T01A051. doi:10.1115/72-GT-52.
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This paper is a feasibility study of the radial inflow compressor. The goal was to study theoretically the flow in such a compressor. The blade loadings have been computed for various pressure ratios and the optimum loading is presented. The rotor efficiency of such a compressor is lower than that encountered in a similar pressure ratio radial outflow impeller. The efficiency in the diffuser is slightly higher for the radial inflow compressor, with an axial relative flow discharge. This combination leads to an efficiency between 70 to 75 percent for a 3:1 pressure ratio compressor stage. This agrees favorably with two-stage radial outlfow compressor in which the two compressors are close together for axial compactness. Thus the radial inflow configuration could give comparable efficiencies when paired with a radial outlfow compressor and more axial compactness. This makes the radial inflow compressor worth considering for use in small auxiliary power units.

Topics: Compressors , Inflow
Commentary by Dr. Valentin Fuster
1972;():V001T01A053. doi:10.1115/72-GT-54.
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A novel analysis of the hub and shroud wall boundary layer growth through the diffusing system of a centrifugal compressor is proposed to model the physical processes. It is shown that the diffuser throat blockage and total pressure loss characteristics can be accurately predicted for a 6:1 PR stage. The static pressure effectiveness and stalling limit are successfully predicted qualitatively, but are underestimated and overestimated by 14 and 12 percent respectively. It is argued that diffuser performance is largely controlled by the combined effect of the boundary layer conditions on the hub and shroud walls at impeller exit and the diffusion required to the diffuser throat. For this reason, it is contended that, for best performance at high pressure ratio (≃ 12:1), impeller exit Mach number must be minimized by employing zero to negative prewhirl at impeller entry which in turn maximizes impeller entry shroud relative Mach number. Performance maps are presented for a single-stage centrifugal compressor based on this premise with specific speed = 90. At 15, 12 and 101 PR, 72, 75 and 76.8 percent efficiency, respectively, were attached at 2.6 lb/sec.

Commentary by Dr. Valentin Fuster
1972;():V001T01A054. doi:10.1115/72-GT-55.
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Flow measurements taken on the rotors of turbomachines are of great value for improved understanding and advancement of design techniques. On-rotor experiments have been limited in the past because of instrumentation problems, especially with the data transmission system. Recent advances in miniature electronic systems and transducer technology have produced a renewed interest in this area. These considerations are discussed, and research on a telemetry-type data transmission system is described with experimental verification using a strain gage on an axial-flow fan blade.

Commentary by Dr. Valentin Fuster
1972;():V001T01A055. doi:10.1115/72-GT-56.
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Both Si3N4 and SiC in their dense forms are leading candidate ceramics for gas turbine components because of their unique physical properties that minimize the thermal stresses which develop during gas turbine operation and their ability to resist oxidation at high temperatures. The purpose of this paper is to present current property data for both materials that are required to calculate thermal stresses, i.e., strength, Young’s modulus, Poisson’s ratio, thermal expansion, thermal conductivity, and specific heat.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A056. doi:10.1115/72-GT-57.
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This paper describes the results from an investigation of the gas-particle flow trajectories, velocities and pressure distribution in an axial flow turbine stage. A gas-particle flow cascade tunnel and high-speed photographic techniques were used to conduct the experimental investigation. The pressure distribution on the blade surface was measured and compared with the theoretical analysis, the results exhibiting good agreement between the developed theory and experiment.

Commentary by Dr. Valentin Fuster
1972;():V001T01A057. doi:10.1115/72-GT-58.
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In the last few years a number of new metal forming techniques have been developed. Some of these which have a potential for becoming important production processes for gas turbine components are reviewed. For each method, the basic principle is first explained, then its present status is reviewed, and some areas in which additional development work is required are pointed out. Finally, the gas turbine components for which the method may be used are indicated. Processes considered include isothermal forging, contoured cross rolling, squeeze casting, radial forging, form rolling, and forging of powder metallurgy preforms.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A058. doi:10.1115/72-GT-59.
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Impingement heat transfer coefficients are presented for a row of holes impinging into an oval cavity with the spent air leaving through holes on one or both sides of the cavity. The distribution around the cavity surface is obtained and is correlated with a survey of the recent literature. In addition, local heat flux gages were used with an impingement jet air supply which could be changed in location along the axis of the test section. This permitted the determination of local heat transfer coefficient distribution over the surface both around the cavity and also in the region between the impinging jets. This two-dimensional distribution is shown to be influenced by the bleed geometry and the shape of the impinging jet holes.

Commentary by Dr. Valentin Fuster
1972;():V001T01A059. doi:10.1115/72-GT-60.
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Analysis of existing gaseous emissions data from gas turbines has shown that a substantial improvement in data correlation is possible. These correlations serve to increase confidence in the data, identify out-of-control points, and facilitate comparisons between engine models. Furthermore, the NOx correlation implies that a simplified primary zone mathematical model may be used to formulate trends or influence coefficients, which may be used to adjust experimental data to a common base for comparison to a specification. Finally, the presence of water vapor in the combustion air is seen to have a noticeable effect on NOx emissions. This effect should be accounted for in comparing experimental results.

Commentary by Dr. Valentin Fuster
1972;():V001T01A060. doi:10.1115/72-GT-61.
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The Variable Pitch fan has a number of features which make it attractive as the basis for ultra-high bypass ratio ducted fans designed primarily for STOL aircraft. The variability imposes certain design constraints, particularly on fan pressure ratio, and leads to differences in engine geometry relative to equivalent fixed pitch engines. The merits of such engines are discussed under the headings of Performance, Noise, Engine Control, Thrust Modulation, Provision of Air Bleed for High Lift, Reverse Thrust and Development Flexibility.

Topics: Fans , Aircraft
Commentary by Dr. Valentin Fuster
1972;():V001T01A061. doi:10.1115/72-GT-62.
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This paper describes the economic and technical justification for applying motor-driven compressors powered by on-site generated electricity. This application is unique in the gas pipeline industry and can be employed only under special conditions. The governing conditions are discussed and the alternatives that were considered are presented. The electrical expertise required for the project was contributed by the major equipment supplier, and the scope of this effort is presented. The equipment has been in operation for more than 14 consecutive months, so that reliable operating costs and experience can also be considered.

Commentary by Dr. Valentin Fuster
1972;():V001T01A062. doi:10.1115/72-GT-63.
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Methods for designing supersonic stator and rotor blading corrected for boundary layer displacement thickness are summarized. Computer programs based on these methods have been reported in NASA publications. Analytical blade losses for blading of this type are presented and design limitations resulting from consideration of flow separation and supersonic starting are discussed. In addition, a summary of the experimental performance of a single-stage turbine designed by these methods is given.

Topics: Design , Turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A063. doi:10.1115/72-GT-64.
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The fossil-fueled, open-cycle gas turbine power plant which incorporates advanced design features derived from aircraft gas turbine engines offers the potential of providing nonpolluting base-load electric power in many regions of the United States at generation costs below that of competing steam electric systems. The results of analytical studies to estimate the performance, size, and cost characteristics of advanced simple-cycle and regenerative-cycle gas turbines which are anticipated to be commercially available in the next two decades are described. The advantages of utilizing waste-heat recovery systems in combination with these high-temperature gas turbines to provide heat (for space heating, air conditioning system operation, process heating, etc.) in addition to electric power for urban communities, while conserving fuel resources and reducing or eliminating air and water pollution, are discussed.

Topics: Gas turbines , Cities
Commentary by Dr. Valentin Fuster
1972;():V001T01A064. doi:10.1115/72-GT-65.
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Low pressure ratio fan engines are receiving increasing attention as a means to provide low speed lift for civilian VTOL transports. Two general types of fan lift engines that are being studied are integral fans and remote powered fans. Preliminary engine design studies of both types of lift fan systems have been made. This paper summarizes a portion of the results of the engine design studies, including the crucial engine requirements, and some of the characteristics of the emerging engine designs of each type.

Topics: Engines , Design , Aircraft
Commentary by Dr. Valentin Fuster
1972;():V001T01A065. doi:10.1115/72-GT-66.
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This paper covers the operating and maintenance experiences with aircraft type light gas turbine driven generators and the use to which they have been put on a New England System over the past nine years.

Topics: Generators
Commentary by Dr. Valentin Fuster
1972;():V001T01A066. doi:10.1115/72-GT-67.
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The object of this paper is to scope the operation of a gas turbine through the magic first 100,000 hr of operation. Using examples of problems, the author attempts to define the philosophy that was generated by the problems and experiences of operating a process gas turbine.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A067. doi:10.1115/72-GT-68.
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The Broken Hills Proprietary Company, Ltd. of Australia is building two gas turbine powered roll-on, roll-off ships. The main propulsion plants of these unique vessels are General Electric Model Series–5002 heavy duty marine gas turbines. This paper describes some of the features of these ships and their gas turbines as well as reviewing the controls and supporting systems.

Commentary by Dr. Valentin Fuster
1972;():V001T01A068. doi:10.1115/72-GT-69.
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The EMU-30/E generator set was developed and produced under contract to the USAF for use in the 407L Tactical Air Control System. For this application, two generator sets, complete with auxiliary equipment, are installed on a pallet to form an A/E24U-8 power plant. One EMU-30/E generator set provides the precise 400-Hz power required for the 3-D radar, computers, communications system, and air conditioning; the second set is on “standby” and will automatically start and assume the electrical load if the operating unit malfunctions. Due to the broad range of operating conditions, precise power limits, high reliability, and low maintenance requirements of the 407L System, the design of the EMU-30/E generator set had to incorporate certain unique features such as solid-state electronic controls, winterization equipment, automatic fault shotdown, and automatic paralleling capabilities. The design concept was based on using proven equipment, such as the Titan gas turbine engine, an alternator, and advanced electronic controls, all packaged into a compact and rugged enclosure and featuring low maintenance requirements and ease of servicing.

Topics: Design , Generators
Commentary by Dr. Valentin Fuster
1972;():V001T01A069. doi:10.1115/72-GT-70.
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The hydrofoil, a ship that overcomes hull resistance by operating with the hull above the water surface, is one type of vessel that is able to cruise at speeds of up to 50 knots in significant sea states. This paper presents a review of the Canadian program directly related to the constructing and trialing of HMCS BRAS D’OR, an open ocean hydrofoil. It summarizes the history of the designing, constructing, and trialing of the vessel. The hull layout, foil configuration, and machinery arrangement are discussed in some detail. Practical operating experience and some results obtained during the trials conducted throughout the program are also described.

Topics: Hydrofoil , Oceans
Commentary by Dr. Valentin Fuster
1972;():V001T01A070. doi:10.1115/72-GT-71.
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This paper is a follow-up to ASME Paper 70-GT-9, “Development of a 3000-HP Industrial Gas Turbine Engine,” and covers further development accomplished during the past two years to adapt the engine to generator drive applications. Specific areas which are covered in detail include: (a) mechanical features of the single-shaft rotor and output drive system as distinct from the two-shaft design; (b) combustor and fuel injections system development for liquid (diesel) fuel and dual fuel capability; (c) fuel control system development; and (d) hydroelectric starting system.

Commentary by Dr. Valentin Fuster
1972;():V001T01A071. doi:10.1115/72-GT-72.
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ST6 gas turbine engines in the 600-shp class have been used in many different vehicles ranging from high-speed turbo trains to Indianapolis roadsters. This experience has lead to the development of operating characteristics and design features of the engine which have improved its performance and reliability. In addition much has been learned about how to rate turbine engines and how to predict maintenance and overhaul periods in vehicular operation. This experience will be useful for future applications of turbine engines to vehicles and for design input to new turbine engines being considered for automotive use. The ST6 has proven itself well suited for prime or auxiliary power use in many types of vehicles.

Commentary by Dr. Valentin Fuster
1972;():V001T01A072. doi:10.1115/72-GT-73.
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This paper deals with the parameters that must be considered in the selection and design of propulsion systems for military VTOL aircraft. Some of these parameters, for instance lightweight, are applicable to engines for all types of aircraft. For the VTOL aircraft, special emphasis must be placed on many of these parameters since aircraft takeoff gross weight determines engine size. Other significant considerations in the selection of the propulsion system include: (a) the ratio of subsonic cruise thrust to maximum thrust; and, (b) exhaust downwash characteristics. Consideration (a) is important because, in the case where no auxiliary lift engines or devices are used, subsonic cruise thrust is about 25 to 30 percent maximum, and at this low power setting, specific fuel consumption is increasing rapidly. Exhaust downwash characteristics are significant because of the variety of landing and takeoff sites likely to be encountered (i.e., shipboard or unprepared fields).

Commentary by Dr. Valentin Fuster
1972;():V001T01A073. doi:10.1115/72-GT-74.
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The ability to fabricate materials and components needed to improve gas-turbine engine performance depends on an ability to achieve reliable joints. Solid-state joining provides this ability. Diffusion bonding of compressor blades, friction welding of engine rotors, and solid-state bonding of turbine shafts by coextrusion of dissimilar metals are discussed as examples of applications of solid-state bonding. Parts made by these techniques have successfully completed engine tests.

Topics: Joining , Gas turbines
Commentary by Dr. Valentin Fuster
1972;():V001T01A074. doi:10.1115/72-GT-75.
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Accurate measurement of the exhaust emissions of aircraft gas turbine engines presents a challenge not only because of the high velocities and temperatures of the exhaust stream, but also because of the variation of the exhaust constitutents over the relatively large-cross-section of the jet stream itself. Other factors which affect exhaust emission level include ambient temperature and humidity. This paper presents the results of independent efforts by Pratt & Whitney Aircraft to identify emission variation characteristics together with results of an exhaust emission documentation program funded by the Environmental Protection Agency. Methods and techniques employed in the above programs are also discussed. The results of these programs indicate that additional effort is required to properly evaluate and understand the emission characteristics of aircraft gas turbine engines.

Commentary by Dr. Valentin Fuster
1972;():V001T01A075. doi:10.1115/72-GT-76.
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The paper outlines the experiences which have resulted from the application of two gas turbine engines (Proteus and Gnome) to provide main propulsion in marine craft. The emphasis is on the use of these engines in the Air Cushion Vehicle (Hovercraft). Summarizing the lessons learned with the Marine Proteus powering fast displacement craft, and the development of the engine for this role, the author then relates this work to the advent of Hovercraft. The fore-running small hovercraft had been largely dependent on the Marine Gnome engine, and much of the experience with both units can be cross-related. Marine Proteus entered the hovercraft world in the larger vehicles. This experience is discussed in some detail, and is further correlated to the continuing build-up of usage of the same engine in Fast Patrol Boats and Hydrofoil Craft.

Commentary by Dr. Valentin Fuster
1972;():V001T01A076. doi:10.1115/72-GT-77.
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The Allison Model 501 industrial gas turbine engine has been used extensively as a prime mover for industrial applications. The areas of application to date have been in the driving of electrical generators and natural gas compressors. This paper describes a 3000-hr durability test of a modified Allison Model 501-K15 engine with saltwater ingestion, 100 F engine inlet air temperature, and operating on Navy distillate fuel. The purpose of the test was to verify that the engine was qualified for marine environmental applications. Performance data, photographs of the installation and engine components, and inspection results are included in this paper.

Commentary by Dr. Valentin Fuster
1972;():V001T01A077. doi:10.1115/72-GT-78.
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Monitoring of velocity variation around airfoil profiles, together with computation of boundary layer variation, have made it possible to increase the aerodynamic loading of turbine blading, that is to say to increase both the Mach number level and the deviation, this being obtained without any reduction of the blading optimum operating envelope. Tests conducted on a flat blade cascade and on a complete turbine stage have permitted first to cross-check and validate the methods in use, and further, to successfully obtain the anticipated results.

Topics: Turbines , Axial flow
Commentary by Dr. Valentin Fuster
1972;():V001T01A078. doi:10.1115/72-GT-79.
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Potential control requirements of various propulsion systems are currently being studied for V/STOL aircraft applications. This paper identifies the considerations which will affect the design of propulsion control systems for both military and commercial aircraft. Of the requirements common to all configurations, the need for improved thrust control is emphasized as requiring total aircraft system trades to establish an approach which provides the desired power management performance with minimum weight and with maximum reliability and maintainability.

Topics: Propulsion , Aircraft
Commentary by Dr. Valentin Fuster
1972;():V001T01A079. doi:10.1115/72-GT-80.
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This paper describes the TP&MS 45 MW Twin Pac, which consists of two counter-rotating gas turbines driving one generator, and describes its development from the time of the first installed unit through March, 1972. The various applications and operating features of the unit are presented with a description of the major equipment which makes up the unit. It also discusses the installation features, including a new testing concept, and some of the problems that have been overcome in the design of the Twin Pac.

Commentary by Dr. Valentin Fuster
1972;():V001T01A080. doi:10.1115/72-GT-81.
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The S.S.S. (Synchro-Self-Shifting) overrunning clutch with its pawl actuated helical sliding motion is well known, particularly in the gas turbine field. This paper reviews briefly the clutch operating principle, then outlines some of the service experience since 1958 in naval main propulsion drives in COSOS, COSAG, CODOG, CODAG and COGOG plant. Extra features are then described such as a lock-out control as is usually necessary for turbine applications to permit turbine testing, e.g., when in harbor; also a lock-in control as is essential when the clutch has to transmit power in both directions of rotation. Various clutch mounting respective advantages. The paper concludes with information regarding reliability during many years of service experience.

Topics: Machinery , Propulsion
Commentary by Dr. Valentin Fuster
1972;():V001T01A081. doi:10.1115/72-GT-82.
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It is in the interests of both the prospective owner and the manufacturer of a gas turbine that equipment be purchased suited to the owner’s maintenance facilities and the features be incorporated to facilitate preventive and corrective maintenance in the intended service. A purchase decision should include consideration of probable cost of maintenance and the procurement document should elicit this information. These considerations together with information which must be provided by a prospective owner and a manufacturer to reach an understanding are discussed in this paper.

Commentary by Dr. Valentin Fuster
1972;():V001T01A082. doi:10.1115/72-GT-83.
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This paper describes a new generation of heavy duty gas turbines manufactured by the General Electric Company. The new unit, known as Model Series 5000 two shaft, has recently been introduced for pipeline service. A detailed description of the design features of the gas turbine is given along with some general comments concerning a typical pipeline installation.

Commentary by Dr. Valentin Fuster
1972;():V001T01A083. doi:10.1115/72-GT-84.
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The technology of fluidics has frequently been advertised as being a solution to environmental problems encountered with more conventional control techniques. However, those applying fluidics to control problems soon discover that fluidic components have their own peculiar sensitivity to changes in the environment. This paper describes the typical environmental sensitivity of fluidic proportional and digital amplifiers, and provides a method for predicting this sensitivity based on the amplifier’s dependence on Reynolds Number. The principal performance parameters considered are gain, noise and null shift. The sensitivity of these parameters to supply pressure, fluid temperature and altitude or reference pressure is described. Both liquid and gaseous fluids are considered.

Commentary by Dr. Valentin Fuster
1972;():V001T01A084. doi:10.1115/72-GT-85.
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This paper discusses the modularization and installation of the FT4 gas turbine engines and the automatic propulsion control system aboard the high-speed container vessel, Euroliner, vanguard of four ships to open a new container transportation system in the North Atlantic.

Commentary by Dr. Valentin Fuster
1972;():V001T01A085. doi:10.1115/72-GT-86.
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After a general indication of the noise problem the relation between conventional and STOL systems are broadly reviewed and their requirements as regards the powerplant are discussed. Some of the associated technical challenges are then considered. These include variable pitch fans, reduction gears, thrust reversal and the environment, (noise and pollution). It is shown that the development of a quiet, clean propulsion engine is perhaps the most important and pressing single task for the powerplant constructor to attack.

Commentary by Dr. Valentin Fuster
1972;():V001T01A086. doi:10.1115/72-GT-87.
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As a result of 22,000 hr gas turbine engine operation burning residual oil fuels of high sulfur concentration, Inconel-700 blade has been severely affected owing to hot corrosion, whereas Inconel-X has been virtually free from such an attack. Consideration of the alloy composition suggests that molybdenum and cobalt in Inconel-700 and iron in Inconel-X are important elements in relation to hot corrosion. On the basis of metallographic, electron microprobe and X-ray diffraction analyses, the effect of the alloy composition in regard to hot corrosion mechanisms has been discussed in some detail.

Commentary by Dr. Valentin Fuster
1972;():V001T01A087. doi:10.1115/72-GT-88.
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A high pressure cannular combustor has been developed to simulate aircraft turbine engine emissions. In conjunction with this combustor, a continuous analytical and sampling system was assembled. This system is capable of complete on-the-spot analysis of CO2, O2, CO, H2O, unburned hydrocarbons, and NOx. The measured emission levels obtained from burning Jet A are in good agreement with those reported from operating aircraft turbine engines. Data showing the effect of equivalence ratio and pressure on the concentration of combustion products are presented.

Commentary by Dr. Valentin Fuster
1972;():V001T01A088. doi:10.1115/72-GT-89.
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A turbojet simulator has been designed and fabricated for use in wind tunnel models. The simulator contains a six-stage, axial-flow compressor powered by a three-stage, axial-flow turbine. High pressure heated air was used to drive the turbine. At design conditions, compressor axial flow, turbine exit flow, and a third supplementary flow all entered the exhaust nozzle at equal values of pressure and temperature. Overall aerodynamic design, instrumentation, and calibration procedure is presented. Performance of the device when used to simulate a J-85 turbojet engine at transonic speeds is reported. The installed nozzle performance obtained with the simulator is also discussed and compared with flight data.

Commentary by Dr. Valentin Fuster
1972;():V001T01A089. doi:10.1115/72-GT-90.
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The subject of this paper is the design and operational characteristics of a 43,000-shp combined gas turbine and steam turbine marine powerplant, known as COGAS. Based upon the “second generation technology” FT4C-2 marine gas turbine, the combined cycle fuel rate is 0.363 lb/shp-hr which represents a thermal efficiency of 41 percent. It is the intent of this paper to show that this low fuel rate design can be achieved with simplicity, operational flexibility, and minimum environmental effect.

Commentary by Dr. Valentin Fuster
1972;():V001T01A090. doi:10.1115/72-GT-91.
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Major design considerations involved in selecting geometries for high-pressure ratio, single-stage centrifugal compressors are discussed. The results of a parametric study are included to indicate optimum regions of design, and to project the potential performance of centrifugal compressors with rotating diffusers. Several different candidate design solutions are evaluated on the basis of providing improved performance at high pressure ratios consistent with maintaining the inherent simplicity and low-cost features of centrifugal compressors.

Commentary by Dr. Valentin Fuster
1972;():V001T01A091. doi:10.1115/72-GT-92.
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Unsteady forces and noise from a fan-in-wing model operated in cross flow are investigated. Based on experimentally determined inlet and outlet flow distortions the unsteady forces on the rotor blades are determined analytically taking into account the effects of blade angle of attack and blade camber. Results of unsteady forces due to flow distortions are compared with those on the rotor blades due to potential interaction with the stator vanes. The calculated unsteady forces on rotor blades are used to calculate the discrete frequency noise emission characteristics of the fan. The predicted sound pressure levels are compared with those due to potential and viscous interactions. It is shown that the predicted unsteady forces on the rotor blades due to cross velocity do not significantly contribute to the noise generated by the fan.

Commentary by Dr. Valentin Fuster
1972;():V001T01A092. doi:10.1115/72-GT-93.
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The development of the regenerative industrial gas turbine has progressed to the point where it can soon take its place with the diesel engine in the heavy-duty power market. The design goals for the Allison GT-404, and the progress in its development are reviewed in detail. The application of the engine to prototype installations in passenger coaches, highway, trucks and generator sets is described, together with significant findings from operating experience to date.

Topics: Engines
Commentary by Dr. Valentin Fuster
1972;():V001T01A093. doi:10.1115/72-GT-94.
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Ceramic components are the key to gas turbines having higher thermal efficiencies and greater specific power outputs than designs that relay solely on cooled metal components. Because of the superior oxidation-sulfidation resistance of ceramics, additional economic benefits can result from the use of lowcost, nondistillate fuels. A program for developing ceramic vanes for a large stationary gas turbine will be discussed in terms of the design and material requirements.

Commentary by Dr. Valentin Fuster
1972;():V001T01A094. doi:10.1115/72-GT-95.
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Investigators have compared results of gas turbine hot section material rig tests to field experiences with identical materials. They proposed that such correlation would be useful for turbine design engineers. But gas turbine users, particularly in the marine field, need a guide to correlate the few reported hot section experiences and realistically project when parts should be replaced. It is suggested that most hot section materials in properly protected marine gas turbines have much lower deterioration rates than those predicted. After coatings on turbine nozzles and blades have been operationally removed, increasingly better predictions of replacement time are possible. Sample at-sea experiences and environmental full-scale test results are offered to illustrate some unity among isolated experiences within a generalized framework of gas turbine hot section deterioration. A method for predicting further useful life of hot parts is proposed. A procedure and tool for in-place nondestructive evaluating of hot section deterioration are offered with a guide for scheduling future maintenance sections.

Commentary by Dr. Valentin Fuster
1972;():V001T01A095. doi:10.1115/72-GT-96.
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The NASA Quiet Engine Program will incorporate all available noise-reduction technology into a propulsion system suitable for subsonic civil transport aircraft. Full-scale experimental hardware is being built and tested primarily for noise performance. The program is in process, and component and engine tests to date indicate that it is possible to achieve or exceed noise reduction objectives of 15–20 PNdB below the levels of 707/DC-8 long-range transport aircraft.

Topics: Engines , NASA
Commentary by Dr. Valentin Fuster
1972;():V001T01A096. doi:10.1115/72-GT-97.
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The resurgence of interest in the heavy duty gas turbine for marine use is due in a large part to its ability to burn residual and crude fuels. Generalities involving fuel treatment requirements have been bandied about for years and often the wrong information is used by unknowledgeable individuals when making quotations or bid evaluations. The purpose of this paper is to present firm information on the treatment of marine fuels for heavy duty gas turbines.

Commentary by Dr. Valentin Fuster
1972;():V001T01A097. doi:10.1115/72-GT-99.
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This paper deals with the parameters to specify a performance of a spray-type combustor which is a high loading combustor for a lift jet engine. The mixing parameter to control a combustion efficiency was obtained analytically by means of simplifying a primary zone, and its effectiveness was confirmed experimentally. The combustor geometry used for the test was 90-deg sector model of an annular type, the 42 combinations of different seven swirlers and six deflectors were tested systematically. The maximum combustion loading of 2.0 × 107 Btu/hr/cu ft combustion volume per atmosphere was obtained.

Commentary by Dr. Valentin Fuster
1972;():V001T01A098. doi:10.1115/72-GT-100.
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A method is presented for experimental data verification on axial supersonic compressors. The actual data are submitted to thoroughly analyzed validity criteria and then accepted, corrected or rejected. An example of experimental results obtained on a rotating supersonic cascade and the final processed data are also shown.

Topics: Compressors
Commentary by Dr. Valentin Fuster
1972;():V001T01A099. doi:10.1115/72-GT-101.
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United Aircraft Corporation studied the potential costs of various possible gas turbine engines which might be used to reduce automobile exhaust emissions. As part of that study, United Aircraft of Canada undertook the preliminary design and performance analysis of high-pressure-ratio nonregenerated (simple cycle) gas turbine engines. For the first time, high levels of single-stage component efficiency are available extending from a pressure ratio less than 4 up to 10 or 12 to 1. As a result, the study showed that the simple-cycle engine may provide satisfactory running costs with significantly lower manufacturing costs and NOx emissions than a regenerated engine. In this paper some features of the preliminary design of both single-shaft and a free power turbine version of this engine are examined. The major component technology assumptions, in particular the high pressure ratio centrifugal compressor, employed for performance extrapolation are explained and compared with current technology. The potential low NOx emissions of the simple-cycle gas turbine compared to regenerative or recuperative gas turbines is discussed. Finally, some of the problems which might be encountered in using this totally different power plant for the conventional automobile are identified.

Commentary by Dr. Valentin Fuster
1972;():V001T01A100. doi:10.1115/72-GT-102.
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The power requirements of large surface effect vehicles are parametrically examined. The results are first derived in terms of total specific power as a function of the cushion to free stream dynamic pressure ratio and other propulsion and lift system parameters. The propulsion, lift and total power requirements are then examined as a function of vehicle speed, vehicle gross weight and daylight clearance. The fuel fraction-range and payload-range relationship for a given cushion pressure is also examined.

Topics: Propulsion , Vehicles
Commentary by Dr. Valentin Fuster
1972;():V001T01A101. doi:10.1115/72-GT-103.
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The design of gas turbine heat recovery boiler systems is based on several engineering and economic parameters that require lengthy iterative calculations. Computer programs have been developed which reduce the time factor and provide the optimum design for a given set of exhaust conditions and steam requirements. This paper describes programs which provide an installed cost estimate that can be used to evaluate the affect of variations in boiler pinch point, back pressure, stack temperature, superheated steam temperature, feed water approach temperature, and supplementary firing for any gas turbine heat recovery application. Another program provides operating performance of the selected boiler design through a range of exhaust conditions due to ambient or load changes, and also for changes in the steam capacity or pressure requirements. Data from this program is used to plot performance “maps” for the full range of “off-design” operating conditions.

Commentary by Dr. Valentin Fuster
1972;():V001T01A102. doi:10.1115/72-GT-104.
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The Alberta Gas Trunk Line’s new 20,000-hp gas turbine compressor set is one of the largest and most modern aircraft derivatives available to industry to date. This paper describes the various aspects of station and unit design for the compressor package. The additional operational flexibility gained as a result of adding this unit to our existing 12,500-hp station is described. The paper will also present a description of the station’s control system, including unit controls, surge controls, and other features of the instrumentation. Trunk Line is concerned with keeping the availability of the unit high, and as such, the paper will describe some features which help keep downtime to a minimum.

Commentary by Dr. Valentin Fuster
1972;():V001T01A103. doi:10.1115/72-GT-105.
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The design of a V/STOL aircraft, incorporating only one lift-cruise engine places great emphasis on the flexibility of its propulsion system to provide sufficient thrust for take-off and efficient fuel consumption for cruise. In order to attain a reasonable range with a lightweight vehicle this inconsistency of thrust and SFC mis-match must be resolved. A brief survey of engine technology predictions for the next decade indicates that future aircraft systems would be offered a wider choice of cycle characteristics, higher technology levels, and added cycle flexibility. A comparative parametric study was conducted to determine the effect of these advancements on a postulated 1983 V/STOL aircraft. In particular the effect of increasing thrust through the use of thrust lapse-rating and variable turbine geometry were compared to more conventional augmentors such as duct burning and water injection. Additionally, the effects of varying cycle characteristics to realize SFC improvements were investigated.

Commentary by Dr. Valentin Fuster
1972;():V001T01A104. doi:10.1115/72-GT-106.
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The design of a vertical or short takeoff and landing airplane powered by jet or turbofan lift engines is primarily an exercise in propulsion package and airframe matching. This task is complicated by the unique requirements and constraints imposed by the takeoff and landing profiles of hybrid jet-lift airplanes. Performance of such aircraft is sensitive to the overall propulsion system capabilities, specifically to thrust vector management, lift-engine bypass ratios, airframe-engine interactions and power plant packaging. In turn, the complete propulsion system design is related to the airplane wing loading and aerodynamic high-lift system. This paper examines the propulsion system/airframe matching considerations that influence the V/STOL vehicle propulsion system design, as seen from the preliminary design engineer’s point of view.

Commentary by Dr. Valentin Fuster
1972;():V001T01A105. doi:10.1115/72-GT-107.
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This paper describes the design of the world’s largest gas turbine powered barge mounted compressor station. This is a completely unattended, remotely controlled station that was mounted on a concrete barge in the United States and towed to Venezuela.

Commentary by Dr. Valentin Fuster
1972;():V001T01A106. doi:10.1115/72-GT-108.
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NOx emission characteristics of four basic types of experimental burners firing kerosene-type fuel at rates up to 110 lb/hr were investigated experimentally. Emission levels were found to be highly dependent upon primary-zone temperature and air-fuel ratio, but independent of firing rate and residence time over a 10:1 ratio. This independence of residence time is in marked contrast with results from simple burners used in fundamental research. The burner with the lowest NOx emission level used a cooled, rich primary zone and a lean secondary zone. Although the work was aimed at automotive Rankine-cycle systems it appears applicable to other compact combustors.

Commentary by Dr. Valentin Fuster
1972;():V001T01A107. doi:10.1115/72-GT-109.
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A radial inlet pressure distortion index is derived using a mathematical compressor model, the two-dimensional continuity equation and the expression for radial velocity upstream of a low hub-tip ratio, multi-stage compressor. These expressions are combined with two conditions required for inlet flow similarity at compressor stall; namely, constant rotor angle of attack and constant ratio of mixing time to air residence time in the blade passage. The theory was tested on a twin-spool turbojet engine at sea level static conditions.

Commentary by Dr. Valentin Fuster
1972;():V001T01A108. doi:10.1115/72-GT-110.
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This paper briefly outlines some of the considerations taken into account in the design and planning of gas compressor stations for the UK Natural Gas Transmission System. Environmental considerations, and in particular the aspects of noise, play a large part in the design of these stations. The requirements for silencing to meet very low ambient noise levels and the development of gas turbine compressor unit enclosures is dealt with in some detail. The need for acoustically efficient and aesthetically pleasing structures is emphasized. The paper compares some representative alternative designs for individual enclosures with the design of an equivalent building and concludes that for small numbers of units, the individual enclosure is the economic solution. Other aspects of noise, including venting of gas are discussed and future design trends indicated. In the consideration of future designs, ease of maintenance and security are fundamental considerations, together with the need to ensure that noise emitted will not pollute the environment.

Commentary by Dr. Valentin Fuster
1972;():V001T01A109. doi:10.1115/72-GT-111.
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This paper discusses the basic design approach and features of the turbotip lift fan concept, initially developed for application in the XV-5 VTOL research aircraft. Design changes necessary to meet the requirements of the proposed NASA V/STOL transport research aircraft and future commercial transport systems are reviewed. Emphasis is placed on the effects of acoustic, installation, control response and life/maintenance objectives on component design and lift fan geometry.

Topics: Design
Commentary by Dr. Valentin Fuster

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