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IN THIS VOLUME


General

1971;():V001T01A019. doi:10.1115/71-GT-19.
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This paper outlines the major design considerations and development experience of a 12,500-hp dual-shaft gas turbine. The unit uses an aircraft derivative gas turbine as the gas generator and is designed to operate in an attended or unattended station without external electrical power above 60 per cent of design speed. Proven power turbine design concepts were combined with the advantages of a variety of highly developed gas generators to produce a reliable machine which could be introduced with a minimum of development time. A special test facility was constructed to subject the unit to a full load test under conditions which simulated field operation.

Topics: Design , Gas turbines
Commentary by Dr. Valentin Fuster
1971;():V001T01A020. doi:10.1115/71-GT-20.
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The current state of a research program to study flows in radial turbomachines at both on- and off-design conditions is described. Numerical solutions of the flow within a rotating impeller are described based on potential theory using a direct method of solution instead of by relaxation. The experimental apparatus comprising a rotating cascade rig is described. The rig consisted essentially of a rotor mounted horizontally in an open circular water tank. An external pipe system enabled the water to be circulated for either radial inflow or radial outflow. The rotor speed could be varied up to 300 rpm. A variety of perspex shrouded rotor geometries up to a maximum diameter of 3 ft 6 in could be tested. Flow visualization by means of polystyrene particles could be observed by a camera mounted above the rotor on its axis and driven at the same angular speed. A 12-channel electronic flash unit enabled the particle velocity and directions to be photographed. As an alternative to the flow visualization system, a bank of manometers, could be mounted above the rotor and driven at the same rotational speed, i.e., with no relative movement. Static pressure measurements could be taken on the blade faces and within the rotor passages. A comparison is made of the experimental and analytical results obtained for one straight vaned, constant area rotor.

Commentary by Dr. Valentin Fuster
1971;():V001T01A021. doi:10.1115/71-GT-21.
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This paper begins with a statement of the acceptance and use of inertia welding in the gas turbine field. A short explanation of the inertia welding process follows. Categories of welds discussed are solid inertia butt welds; tubular inertia butt welds; and angular-annular inertia butt welds. An example of the first category is a bimetallic engine valve. The second category is typified by steel shafts joined to superalloy rotors for turbines. The joining of wrought superalloy disks to cast superalloy blade rings to produce a composite wheel comes into the third category. The effect of welding parameters on strength and microstructure, as well as design and process changes required for inertia welding are related. In conclusion, basic considerations for utilization of inertia welding are expressed.

Commentary by Dr. Valentin Fuster
1971;():V001T01A022. doi:10.1115/71-GT-22.
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This paper presents details of three large gas turbine installations in the Freeport, Texas, power plants of the Dow Chemical Company. The general plant layout, integration of useful outputs, economic factors leading to the selection of these units, and experiences during startup and operation will be reviewed. All three units operate with supercharging fan, evaporative cooler, and static excitation. Two of the installations are nearly identical 32,000-kw gas turbines operating in a combined cycle with a supplementary fired 1,500,000-lb/hr boiler and a 50,000-kw noncondensing steam turbine. The other installation is a 43,000-kw gas turbine and a 20,000-kw starter-helper steam turbine on the same shaft. The gas turbine exhaust is used to supply heated feedwater for four existing boilers.

Commentary by Dr. Valentin Fuster
1971;():V001T01A023. doi:10.1115/71-GT-23.
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The final phase of the development program of 3000-hp turbine included an inservice field evaluation. El Paso Natural Gas Co. shared in this phase by installing one of the two prototype units in gas transmission service. This paper describes the unit and its application and reviews the first year’s operation including inspections, tests and modifications.

Commentary by Dr. Valentin Fuster
1971;():V001T01A024. doi:10.1115/71-GT-24.
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This paper describes the design and experimental evaluation of a vane-type fuel pump that has operated successfully at speeds up to 49,500 rpm and outlet pressures up to 900 psig. The objective of the research was to produce a main-engine fuel pump for small gas-turbine engines capable of operating at engine shaft speed in order to reduce the bulk and complexity of the required gear drive train. The pump has a design JP-4 turbine-fuel flow rate of 2000 lb/hr at 650 psig. The successful completion of a 200-hr endurance run has verified that the high-speed capabilities have been achieved without sacrificing pump endurance life.

Commentary by Dr. Valentin Fuster
1971;():V001T01A025. doi:10.1115/71-GT-25.
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The influences of the Reynolds number on centrifugal compressor performance have not so much been investigated. Especially, the experimental equation representing the rates of losses for the critical Reynolds number has been seemingly not established. Namely, the coefficients in the equation differ with each investigator. In the present study, an experiment was conducted by means of an experimental centrifugal compressor. From the results, it was found that the critical Reynolds number Recmeancr was reasonable for the compressor stage as well as for the impeller, and for the former it amounted to about 0.9∼1.3 × 105, while for the latter it amounted to about 0.9∼1.2 × 105. On the other hand, the critical Reynolds number Rec2cr was also found appropriate for the diffuser and it amounted to about 0.9∼1.5 × 105. In addition, the coefficients in the experimental equation which introduced the rate of losses were estimated.

Commentary by Dr. Valentin Fuster
1971;():V001T01A026. doi:10.1115/71-GT-26.
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An attempt is made in this paper to inform the reader of the noise sources which are a problem when attempting to meet various criteria. Starting with the relatively easy-to-meet criteria of NEMA H to the more difficult NEMA D, and the stringent criteria of NEMA B, various noise components which could cause the overall system noise level to miss the specified criteria are considered, and their effect to the system is shown.

Commentary by Dr. Valentin Fuster
1971;():V001T01A027. doi:10.1115/71-GT-27.
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Aircraft-type gas turbines have been used by Consumers Power Co. to provide power for the injection of natural gas into underground storage for the past five years. Special controls, auxiliary and driven equipment are required for this unique application. Operating experience has prompted numerous refinements as well as providing information for maintenance and economic planning. The paper describes the basic design of the engine-compressor units for a remotely controlled, unmanned compressor station as well as highlights from the operating experience with this application.

Commentary by Dr. Valentin Fuster
1971;():V001T01A028. doi:10.1115/71-GT-28.
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The development of the cryogenic turbo-expander type plant as applied to natural gas processing for the recovery of ethane and heavier hydrocarbons is traced briefly. Integration of a large gas fired turbine into this process for a marine installation is discussed. Design considerations are outlined and operating experience is reviewed.

Commentary by Dr. Valentin Fuster
1971;():V001T01A029. doi:10.1115/71-GT-29.
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The trend toward electronic controls for turbine engines because of their flexibility in meeting the requirements of the more complex gas turbine operating cycles suggests possible problems in view of the minor electrical malfunctions routinely experienced by jet transport aircraft. High by-pass ratio turbine engines can provide a possible close coupling path for surges into engine control wiring and approaches to alleviate this possible problem are suggested, including component arrangement, shielding approaches, the use of protection devices and thorough surge testing of the developed systems.

Commentary by Dr. Valentin Fuster
1971;():V001T01A030. doi:10.1115/71-GT-30.
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This paper consists of the application considerations given for the selection of on-site power generation using a gas turbine with a recovery boiler in the process chemical industry. The additional use of 400 psig steam from recovery heat of the gas turbine exhaust used for process steam is evaluated. The techniques used for engineering, construction, training, and start-up are discussed. The performance of the unit after 30,000 operating hours, including reliability and a discussion of equipment problems, is included.

Commentary by Dr. Valentin Fuster
1971;():V001T01A031. doi:10.1115/71-GT-31.
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The control and limiting of gas turbine speed and temperature is most readily achieved with an electronic fuel control system. The control system to be described is practical hardware for vehicular applications. The same basic electronics used with a suitable choice of fuel metering valve and choice of actuator for whatever means of torque transfer is employed, provide proper control for a turbine of any horsepower rating using liquid or gaseous fuels. Minor modification in the electronics can adapt the control for generator sets and other industrial applications.

Commentary by Dr. Valentin Fuster
1971;():V001T01A033. doi:10.1115/71-GT-33.
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The fabrication of jet engine rotors by joining simple disk and ring shapes offers both weight and cost advantages; however, the metal joints must have excellent and completely reproducible mechanical properties. Inertia welding achieves this since it is a solid state joining process which forges the two parts together under an automatically controlled situation. The parameters for inertia welding jet engine nickel and titanium alloys are discussed. The cost and weight advantages occurring from elimination of mechanical joints and better material utilization are identified. Several typical applications are described.

Commentary by Dr. Valentin Fuster
1971;():V001T01A034. doi:10.1115/71-GT-34.
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This paper deals with a hodograph method for design of turbine cascades in high subsonic flow and an approximate solution to a gas, specific heat ratio γ = −1 (the Karman-Tsien approximation) and γ > 1 (the gas obeying the adiabatic law). Numerical examples and a comparison of theoretical and measured pressure distribution for profiles designed by this method are given. Further, a better criterion for design to improve cascade efficiency is also presented.

Commentary by Dr. Valentin Fuster
1971;():V001T01A035. doi:10.1115/71-GT-35.
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A brief statistical comparison of the application of gas turbines to gas pipeline compressor drives in North America and Europe is given. Basic similarities in the installations in North America and in Eurpoe are discussed briefly. Differences in application, in installation, in equipment, and in operation are shown. The factors — geographical, political, and operational — which are responsible for these differences are discussed. Future trends in North America and Europe and factors which may influence the elimination of some of the present differences but which may create new ones are also presented.

Commentary by Dr. Valentin Fuster
1971;():V001T01A036. doi:10.1115/71-GT-36.
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A gas turbine generator set intended for use as an emergency power source has been evaluated and tested using a computer controlled data acquisition and processing system. At 1-sec intervals during startup, transducer devices monitor such items as turbine inlet temperature, compressor discharge pressure and speed. While operating under normal or steady-state conditions, a total of 65 parameters are logged at 5-min intervals. In addition, power, specific fuel consumption and efficiency are calculated every 5 min. Computer output is in engineering units (deg F, psi, cfm, etc.). The computer programming language is structured with Fortran-like arithmetic and formatting capabilities. Analog-to-digital conversion is accomplished by an integrating digital voltmeter and switching via a 200-channel reed relay scanner. Two teletypewriters, a programmable clock, and 64,000 words of disk storage comprise the rest of the major hardware. For this project 4096 words of computer core were implemented. A turbine development program conducted with this computerized data system can be completed by a single appropriately trained individual in approximately half the time required by a team of three or four using conventional data gathering methods.

Commentary by Dr. Valentin Fuster
1971;():V001T01A037. doi:10.1115/71-GT-37.
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Existing gas pipeline facilities in Western Canada are outlined. The paper points out the trend away from industrial type gas turbines, and points out the advantages to using aircraft type gas turbines. The expansion of pipeline facilities to the Canadian Arctic and Alaska could prove to be a market for the new high efficiency aircraft type gas turbines. The fuel gas savings can be a significant factor when constructing the new line.

Commentary by Dr. Valentin Fuster
1971;():V001T01A038. doi:10.1115/71-GT-38.
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Low pressure drop fuel injectors for jet engine combustors are currently being considered. In this respect, the general problem considered in this paper is the flow variables affecting the distribution of a low pressure drop, low velocity stream of liquid which is convected by a concentric airstream against a concave hemispherical cap similar to possible fuel injectors designs (Fig. 1). Experimental results from a plexiglass model of the injection system are presented. The experimental results indicate that for a centrally located liquid stream injector (less than 1/16 in. from the true center), the momentum ratio between the liquid and air streams is the predominant factor which influences uniform fuel distributions. More uniform distributions are obtained with higher liquid-to-air momentum ratios. For larger injector eccentricities, the liquid distributions exhibit variable tendencies depending on the range of the momentum ratio.

Commentary by Dr. Valentin Fuster
1971;():V001T01A040. doi:10.1115/71-GT-40.
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Velocity profile measurements were performed on the flow in a mixed-flow diffuser with walls having equal cone angles. The aim of the present study is to understand the flow behavior and the relation between the flow patterns and the diffuser losses. The boundary layer flow accompanied by separation on the inner wall and the velocity normal to the diffuser walls were measured in detail to examine the three-dimensional flow behavior in the mixed-flow diffuser. Comparing with the radial diffuser, the mixed-flow diffuser had a more complicated flow mechanism as it had the pressure gradients of transverse and normal directions.

Commentary by Dr. Valentin Fuster
1971;():V001T01A041. doi:10.1115/71-GT-41.
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An Investigation of the flow patterns within the centrifugal and mixed-flow impeller channel were performed. The velocity distributions within the impeller channel and blade surface pressure of the centrifugal and mixed-flow impellers were closely examined by experiment and the flow behavior within these impellers were clarified. The incompressible and inviscid flow within the impellers having straight radial blades were also derived analytically. The present authors assumed an outermost boundary of the relative eddy at the impeller exit periphery and corrected the analytical results. The corrected analytical results thus obtained showed good coincidence with the experimental data.

Commentary by Dr. Valentin Fuster
1971;():V001T01A042. doi:10.1115/71-GT-42.
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A numerical technique is presented for the calculation of steady inviscid transonic flows in turbomachinery cascades, wherein both subsonic and supersonic regions co-exist. The problem is posed in the time-dependent form and the aysmptotic solution at large times provides the solution of the steady physical problems. The solutions for a hyperbolic nozzle cascade and two turbine cascades are compared with other analytical solutions and with an experimental result. The agreement appears to be very good. Some preliminary results are presented for a flow containing an oblique shock and its reflection. The computed results compare satisfactorily with the exact solution.

Commentary by Dr. Valentin Fuster
1971;():V001T01A043. doi:10.1115/71-GT-43.
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A new type aircraft starting system is now operational in the A-7D aircraft. A general description of the system, its components and operation are covered. The Jet Fuel Starter, a small gas turbine and heart of the new system, is described in detail. History, operational experience, problems encountered, and preproduction testing of the Air Force Type STU-26/A Jet Fuel Starter are reviewed.

Topics: Jet fuels
Commentary by Dr. Valentin Fuster
1971;():V001T01A044. doi:10.1115/71-GT-44.
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A fluidic valve, consisting of a swirl chamber with tangential and radial inlets and a single outlet, has been used to provide uniform fuel distribution to the nozzles in an annular combustor designed for a small turbine engine. The fuel nozzles were of the air atomizing type, with large flow passages for contamination tolerance. Pressure drop across the nozzles was too small at low fuel flows to overcome hydraulic heat effects and uniformly distribute the fuel to the nozzles. A fluidic valve installed in series with each nozzle provided sufficient pressure drop to distribute the fuel at low flow rates without requiring exceptionally high fuel pressures at large flow rates. The fluidic valves were fed by a dual man fold fuel system. Fuel flow was divided between the two manifolds, which were connected separately to the tangential and radial inlets of the fluidic valves, by a pressure relief valve. The flow schedule of the system was similar to that of a dual orifice pressure atomizing fuel system. Turn down requirements of the system were 40:1.

Topics: Fuels , Gas turbines , Valves
Commentary by Dr. Valentin Fuster
1971;():V001T01A045. doi:10.1115/71-GT-45.
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Development of an aircraft fuel tank nitrogen system to suppress fire and explosion has been underway for several years. As work progressed it was learned that such a system could also reduce contamination in the fuels. Reduction of contamination will reduce fuel system component malfunctioning, improve aircraft performance, and possibly eliminate the need for fuel additives and exotic fuels.

Topics: Fuels , Nitrogen
Commentary by Dr. Valentin Fuster
1971;():V001T01A046. doi:10.1115/71-GT-46.
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Metal matrix composites constitute an attractive class of materials which must be considered as serious candidates for application in advanced gas turbine engines. Materials development programs have been successful in fabricating and characterizing metallic composite materials. Demonstration programs have shown that aerospace structural components can be fabricated from them. This paper deals with the application of the diffusion bonding process to the formation of a complex shape such as a gas turbine engine fan blade from titanium or aluminum matrix composites. It deals with the route to volume producibility rather than with the documentation of progress to date.

Commentary by Dr. Valentin Fuster
1971;():V001T01A047. doi:10.1115/71-GT-47.
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Fan and compressor blades for gas turbine engines were identified early as potential applications for resin matrix composites. However, for these composites to reach production status, they have to be more effective than existing metal blades in both performance and cost. Graphite fiber and prepreg prices were surveyed for development and initial production price trends because composite material prices represent a significant portion of total part cost. Resin matrix composite airfoil construction is briefly described to aid in a later description of the related fabrication sequence. Manufacturing methods as currently anticipated for high volume production are discussed with regard to the fabrication sequence and effective material utilization. Quality requirements and appropriate inspection methods, both dimensional and nondestructive, are briefly reviewed. Several examples of current prototype work are described as they relate to proving out certain production processing concepts. It is important to work out volume production manufacturing methods concurrent to the composite blade design and engine testing efforts because both technologies have to be available if composite blades are to be accepted for use in an advanced technology engine.

Commentary by Dr. Valentin Fuster
1971;():V001T01A049. doi:10.1115/71-GT-49.
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The text deals with an evaluation of a gas turbine drive refrigeration system after four years of operation. Comparison is made of actual performance, operating, and maintenance costs with original system design concept, goals, and objectives.

Commentary by Dr. Valentin Fuster
1971;():V001T01A050. doi:10.1115/71-GT-50.
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The purpose of this paper is to discuss several economic factors commonly used in the evaluation of equipment for the industrial user. The effect of major operating and fixed cost variables is illustrated. Also included are several curves which permit rapid evaluation of net payout, end of period cumulative net cash flow, and discounted rate of return after Federal income taxes once the gross payout period has been established. The application of these economic factors and investment criteria are illustrated by use of an example comparing two energy supply systems for a process requiring both power and heat.

Commentary by Dr. Valentin Fuster
1971;():V001T01A052. doi:10.1115/71-GT-52.
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The design of the first compact AK Process Nuclear system in the United States was performed under the auspices of the Corps of Engineers. U. S. Army, Fort Belvoir, Va. Taking into account that there was virtually nothing on the shelf that could be used, and realizing that the feasibility of such a system first had to be established, demonstration models were built for the various subsystem components which were to eventually go into the complete system. The last and final turbine-compressor set tested as a backup unit for this program was the TCS 670-B. This paper reports the turbine performance obtained from this machine when tested in the Closed Cycle Test Facility (APCEF) at Fort Belvoir, Va.. in 1969. The compressor performance is not included.

Commentary by Dr. Valentin Fuster
1971;():V001T01A053. doi:10.1115/71-GT-53.
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This paper describes the design of a combined cycle power plant for intermediate peaking with particular reference to design features resulting in simplified control and operation.

Commentary by Dr. Valentin Fuster
1971;():V001T01A055. doi:10.1115/71-GT-55.
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With increasing international competition and the formation of the common market, a large chemical company producing chlorine and soda decided that it was imperative to reduce to a minimum the costs of its electricity and steam requirements without loss of reliability of supplies. After several schemes had been carefully costed it was concluded that a total energy scheme using packaged ags turbines, burning an economic oil fuel particularly suitable for high temperature machines should be adopted. The gas turbines exhaust through natural circulation heat recovery boilers to produce sufficient steam to meet all the process requirements. This paper reviews the uses of gas turbines in total energy systems, describes the actual fuel adopted, and gives a comprehensive description of the particular plant installed. Some notes on the plant performance up to the time of the submission of the paper are also included.

Topics: Fuels
Commentary by Dr. Valentin Fuster
1971;():V001T01A056. doi:10.1115/71-GT-56.
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Heavy distillate fuel oils are being offered for use in gas turbines at a significant reduction in fuel cost. This paper will summarize the characteristics of some of these fuels, their effect on gas turbine combustion performance, and the problems associated with their use.

Commentary by Dr. Valentin Fuster
1971;():V001T01A058. doi:10.1115/71-GT-58.
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This paper describes the results of tests to determine the effects of steam injection on the production of nitric oxide in gas turbine combustors. When the steam injected into the compressor discharge was 2 percent of the total air flow, the oxides of nitrogen were reduced to 50 percent of what they were with no steam injection for a given load in a gas fired machine. When the steam flow was increased to 4 percent the oxides of nitrogen dropped to 25 percent of the value with no steam.

Commentary by Dr. Valentin Fuster
1971;():V001T01A059. doi:10.1115/71-GT-59.
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The design requirements of thrust bearings for power gas turbines are discussed with reference to designs which have given satisfactory service. The shortcomings of these designs are analyzed both from the point of view of efficiency and that of service experience. The development of a new system of lubrication designed to overcome these shortcomings is outlined. It is shown that this system, when applied to tilting pad thrust bearings in power turbines, can result in a simpler bearing assembly with increased load capacity and substantially ower power losses.

Commentary by Dr. Valentin Fuster
1971;():V001T01A060. doi:10.1115/71-GT-60.
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The paper outlines a quasi-three-dimensional approach based on the solution of the entire inviscid momentum and energy equations in the meridional and blade-to-blade plane to calculate the blade loading in a radial flow turbomachine. The method is outlined in detail so as to enable the reader to adapt it for use on his computer. The flow in the compressor is considered to be nonhomentropic with variations of thermodynamic properties at the inlet. A comparison of various inlet distributions is shown and this illustrates the usefulness of this method. Calculation of the velocity on the trailing and driving faces of the blades is obtained. Pressure and temperature distribution throughout the flow passage considering an actual process is also outlined.

Commentary by Dr. Valentin Fuster
1971;():V001T01A062. doi:10.1115/71-GT-62.
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A Pratt & Whitney FT4A Marine Gas Turbine Engine rated at 22,600 hp, 3600 rpm was run at the Naval Ship Engineering Center, Philadelphia Division for 1000 hr. Fuel used was naval distillate having a vanadium level of 0.5 ppm. Basically there was no problem with engine operation on naval distillate when compared to diesel fuel. The smoke level was barely visible at high powers. Coalescent fuel filters are a problem due to their relatively short (100–130 hr) life. The corrosion rate was accelerated when compared to navy diesel fuel. The fuel parameter suspect is vanadium, however other parameters may be at fault. Additional efforts are required into definitely determining the cause of accelerated corrosion and also into optimizing nozzle guide vane and turbine blade base materials and coatings.

Topics: Fuels , Gas turbines , Testing
Commentary by Dr. Valentin Fuster
1971;():V001T01A063. doi:10.1115/71-GT-63.
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The unique control problems associated with vehicular gas turbine engines are forcing the requirement for more direct measurement and control of vehicular gas turbine operating parameters. Two of the most important parameters are gas generator turbine inlet temperature and engine flameout. The major problem controlling these parameters has always been the lack of low cost sensors with sufficient accuracy and response for closed loop control along with the life required for economical operation. Two sensors have been developed which have the necessary response and accuracy for application to vehicular gas turbine controls. These sensors are also rugged and reliable and will provide the required long life. A fluidic temperature sensor measures turbine inlet temperature and an ultraviolet radiation sensor detects the presence of flame. Both sensors have electronic outputs and are readily adaptable to present electronic control systems. The principle of operation, accuracy and response data, along with application and installation information is presented for both sensors.

Commentary by Dr. Valentin Fuster
1971;():V001T01A064. doi:10.1115/71-GT-64.
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Olin’s five-year experience in gas turbine operation shows the ammonia process, turbine and services rendered by the turbine with relation to the process. A start up and shutdown procedure is outlined as to the sequel steps followed at each start-up and shutdown. The final phase of the paper relates Olin’s experience in operating the gas turbine for the past five years. Explanations of problems and corrective action taken are included, along with some humorous experiences encountered.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1971;():V001T01A065. doi:10.1115/71-GT-65.
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This paper describes the handling characteristics of a simulated, gas turbine powered vessel using several different transmission schemes. These include both mechanically clutched and hydrodynamic reversing reduction gears, and two modes of operation using controllable, reversible pitch propellers. Schemes for controlling the various transmission systems are described together with the necessary integration to provide “single lever” propulsion control. The response of the simulated systems are presented for both normal and emergency maneuvers.

Topics: Gas turbines , Ships
Commentary by Dr. Valentin Fuster
1971;():V001T01A068. doi:10.1115/71-GT-68.
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This paper gives a brief summary of the experience of the first industrial gas turbine ship, the John Sergeant, then enumerates the basic characteristics of the heavy duty gas turbine and the philosophy employed in the design. The unique features of the second-stage variable area turbine nozzle, its effects on performance, and particularly the flexible control it affords in conjunction with the controllable and reversible pitch propeller, are discussed. The philosophy of design of the solid state control, protection and sequential systems are outlined, as are the experiences to date with a number of industrial gas turbines of the two-shaft, off-shore and heavy fuel varieties. It concludes by discussing some of the considerations for burning residual fuel and boil-off from liquefied natural gas.

Commentary by Dr. Valentin Fuster
1971;():V001T01A069. doi:10.1115/71-GT-69.
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Results of low cost gas turbine engine design studies are presented. System requirements are discussed and their effects on engine design and cost are analyzed. Parametric performance data are presented and the use of these data in engine build cost trades is discussed. The evolution of specific component fabrication techniques on selected components is discussed, and the overall effect on the engine cost is analyzed and described. The technique of achieving low manufacturing costs by the use of innovative design, keyed to operational requirements rather than new processes, is described. The accessory problem is discussed and a potentially low cost fuel control concept described. A cross section drawing of a simple production turbojet is shown and the use of a technique for low cost design is outlined.

Topics: Design , Gas turbines
Commentary by Dr. Valentin Fuster
1971;():V001T01A070. doi:10.1115/71-GT-70.
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The integrated theoretical and experimental efforts of the Rotor Burst Protection Program (RBPP) are providing the needed design data and material evaluations to assist any turbomachine manufacturers to provide satisfactory, protective systems without imposing large weight penalties on the equipment. The need for the RBPP is clearly indicated by the uncontained failure statistics included. Experimental observations are made relative to such important factors as fragment type, blade effects, ring plastic growth, ring restraint, fragment energy distribution, ring cross section, and radial clearance. Transient ring response computer codes being developed by the Massachusetts Institute of Technology are described.

Topics: Design , Rotors
Commentary by Dr. Valentin Fuster
1971;():V001T01A071. doi:10.1115/71-GT-71.
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The electric utility industry is finding a need for a new class of generation termed intermediate. This paper presents results of generation addition pattern studies performed to determine the relative merits of steam peaking plants and combined cycle plants in filling these needs. Corresponding optimum addition patterns are established for simple cycle gas turbine and nuclear power plants. The combined cycle and steam peaking plants are shown to be comparable at high cost levels, while the combined cycle shows definite advantage if permitted to burn non-distillate fuel.

Commentary by Dr. Valentin Fuster
1971;():V001T01A072. doi:10.1115/71-GT-72.
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Hydrogen, ammonia, and nitrogen coolants were used in a study of combustion effects on transpiration cooling. It was found that hydrogen combustion at low coolant blowing rates resulted in increased porous surface temperatures. However, at higher blowing rates (F > 0.002), hydrogen was more effective in surface temperature reduction than the other coolants. It is demonstrated that assumption of temperature equality of coolant and wall leads to erroneous results in heat transfer determination.

Commentary by Dr. Valentin Fuster
1971;():V001T01A073. doi:10.1115/71-GT-73.
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The subject of main engine combustor stability is viewed from the perspective of two interacting dynamic chambers — on the one hand, the premixing or vaporizing chamber which supplies fuel ladened air to a second chamber where combustion takes place. The system is modeled with each of the two chambers as a Helmholz resonator each with an orifice to a constant reference pressure, and with a third orifice interconnecting the two subsystems. Futhermore, it is hypothesized that a dynamic heat release is possible which is proportional to the velocity of the fuel ladened air exiting from the premixing chamber into the combustion chamber. On the basis of this model, a stability criterion is derived which gives the critical combustor temperature ratio as a function of geometry of the combustor — the two-chamber volumes and the effective perimeters and areas of the orifices. Additionally, the frequency of oscillation of the unstable system is derived as a function of these same parameters. The analytic result suggests that the most potent configuration detail that can be manipulated to eliminate or avoid instability is ratio of the natural frequency of the premixing chamber of the natural frequency of the combustion chamber (as computed with the passage between the premixing chamber and the combustion chamber blocked). If this ratio can be maintained above unity, stability is assured.

Commentary by Dr. Valentin Fuster
1971;():V001T01A074. doi:10.1115/71-GT-74.
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Holography, by virtue of its three-dimensional recording characteristic, offers a process for performing interferometry on nonplanar, diffusely reflecting objects. As such, it has found application in many areas. Furthermore, the use of pulsed laser techniques provides a method for studying dynamic, nonrecurring three-dimensional events, with or without the interferometric feature. More importantly, the pulsed holographic capability eliminates environmental vibration problems, often encountered in holography, thereby permitting its use in hostile, field situations whether the subject be static or dynamic. A holographic study program to examine possible applications of both the CW and pulsed laser methods has been in progress at United Aircraft Research Laboratories for several years. More recent investigations in this area are summarized with the intent of describing the several tools which have been developed and are now available for studying the various problems confronting the aerospace industry. Several examples will be described. Investigations at UARL in this particular area have included examination of various PT-6, JT-9D, and JT-8D components, as well as more general studies of fuel nozzle spray characteristics, aerospace materials bond inspection, and rotor flow visualization studies.

Commentary by Dr. Valentin Fuster
1971;():V001T01A075. doi:10.1115/71-GT-75.
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As part of the program for developing VTOL craft, the National Aerospace Laboratory (NAL) of the Japanese Government installed two JR100 lift jet engines on their Flying Test Bed, following upon the successful outcome of tests on the Height Control Tower with other JR100 engines. These JR100 engines were developed in a joint effort between NAL and IHI. Five engines in three successively modified version have been produced, and the aggregate number of runs has already reached 1700, recording accumulated operating time of more than 200 hrs. The engine which has a 6-stage compressor, an annular combuster and a single-stage turbine, produces 3350 lb thrust and weighs 340 lb.

Topics: Jet engines
Commentary by Dr. Valentin Fuster
1971;():V001T01A076. doi:10.1115/71-GT-76.
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Fundamental concepts are given for the design of a turbine stage with supersonic gas velocities relative to the blading. Minimum-length nozzles (stators) and free-vortex-type rotor blades are specified and a correlation of their published performance is given. A blade selection chart is given to provide a method for obtaining appropriate low-loss rotor blade configurations. A series of two-dimensional cascade experiments are described in which the performance of film-cooled, blunted leading-edge rotor blades were measured. Blade performance is given over a range of inlet Mach numbers and cooling flows.

Commentary by Dr. Valentin Fuster
1971;():V001T01A077. doi:10.1115/71-GT-77.
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This paper discusses the test results of an automatic, real-time Engine Performance Monitoring System (EPMS) which was flight tested on-board a commercial airline B-707-321B aircraft. EPMS employed the steady-state technique used in test cells to determine the “health” of the operating jet engine. Additional techniques and applications being developed by Emerson Electric Co., such as the portable ground based jet engine analyzer and the NAVY Jet Engine Transient Health Analyses Study, are also discussed.

Commentary by Dr. Valentin Fuster
1971;():V001T01A078. doi:10.1115/71-GT-78.
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In these days, there has been a progressive increase in the application of gas turbines to the industrial field in Japan. Based on favorable reliability, the increasing demands of electric power have created the high capacity of gas and steam turbine combined plants.

Commentary by Dr. Valentin Fuster
1971;():V001T01A081. doi:10.1115/71-GT-81.
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The newly enacted requirements of desulfurization brought about a sudden change in the fuel market of the industrial gas turbine: oils became available at a price considerably below that of distillate oils. These oils present a new option for the gas turbine industry to avoid the difficulties of the lower priced residuals, without the high cost of the No. 2-GT distillate. Work performed by the author’s company to introduce these oils is presented in this paper.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1971;():V001T01A082. doi:10.1115/71-GT-82.
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Recent requirements for marine propulsion gearing have dictated the analysis of and designs for reversing reduction drives with very high power levels, utilizing aricraft type gas turbines as prime movers. Service in either high-speed cargo vessels or ships operating in icebound waters is contemplated. Individual design features of the drive assemblies as well as methods of control and response to transient conditions is explored.

Topics: Gas turbines
Commentary by Dr. Valentin Fuster
1971;():V001T01A083. doi:10.1115/71-GT-83.
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Why choose the aircraft type gas turbine for ship propulsion? Initial cost, weight, space, floor area, engine room height, fuel cost, and other operating costs are the factors determining the selection of the propulsion plant. A comparison of these factors with regards to containerships and tankers is evaluated. It is evident from the results that total economics favors the aircraft type gas turbine power-plant.

Commentary by Dr. Valentin Fuster
1971;():V001T01A084. doi:10.1115/71-GT-84.
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Holographic techniques have been employed to study various turbine blade characteristics. The studies were performed using both helium-neon continuous wave (CW) and ruby pulse lasers to generate static double-exposure (CW), dynamic time-average (CW), or dynamic double-exposure (pulsed) interferometric holograms. In general, the interferometric holograms reconstruct the turbine blades in two different states of stress and produce a set of bright and dark interference fringes (on the reconstructed image) which represent contours of equal surface displacement. The turbine blade was stressed in several ways. The displacement contours obtained were used to define and evaluate characteristics of the blade. Described in detail are results of holographic surface strain measurements made on both solid and hollow turbine blades. Comparisons are also made with conventional strain gage measurements. A review of the resonant modes present on turbine blades and an analysis of the resulting interferometric fringe patterns are made. Vibrational excitation, of up to 45,000 Hz, is examined. Also included are preliminary results of studies for inspecting hollow turbine blades using internal pressurization as a means for detecting internal damage or flaws; and for obtaining a qualitative measure of turbine wall thickness using acoustic vibration. Finally, results of an experimental investigation concerned with the effects of temperature on turbine blade holography are described and principal results reviewed.

Topics: Turbine blades
Commentary by Dr. Valentin Fuster
1971;():V001T01A085. doi:10.1115/71-GT-85.
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The design and development of a composite material front housing for the reduction gear of the T56 engine are discussed. The program was undertaken to advance the state-of-the-art in engine structures by making a material available that is capable of replacing aluminum and magnesium. The selected boron-glass-epoxy material exhibits high strength and specific stiffness, light weight, good corrosion resistance, and suitability for molding. The design, molding, machining, and testing phases of the programs are described.

Commentary by Dr. Valentin Fuster
1971;():V001T01A087. doi:10.1115/71-GT-87.
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Conditions peculiar to Europe have resulted in stringent noise level requirements being placed on industrial facilities where these facilities are located outside of industrial areas. Compressor stations, for example, are being constructed to conform to very severe noise limitations. Commonwealth Associates has participated in the design and installation of compressor stations in The Netherlands, and England. This paper describes the noise limitations imposed in these countries and the methods used to achieve these limitations.

Commentary by Dr. Valentin Fuster
1971;():V001T01A088. doi:10.1115/71-GT-88.
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A standard system (equipment and procedures) for measuring smoke emitted by aircraft turbine engines has been developed. It has been adopted by several Federal Government agencies. In this paper, the system is explained and its accuracy defined. An experimentally determined relationship between the system’s parameters and true smoke density (weight of solids per unit volume) is presented and theoretically examined. The definition of smoke plume visibility in terms of the system’s parameters is also developed. This work led to the conclusion that aircraft turbine engine exhaust smoke is composed of two groups of particles: the very small, which are primarily responsible for visible obscuration, and larger particles, which may constitute as much as half of the total by weight, but do not appreciably contribute to plume visibility.

Commentary by Dr. Valentin Fuster
1971;():V001T01A089. doi:10.1115/71-GT-89.
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Steady transonic flow through two-dimensional gas turbine cascades is efficiently predicted using a time-dependent formulation of the equations of motion. An integral representation of the equations has been used in which subsonic and supersonic regions of the flow field receive identical treatment. Mild shock structures are permitted to develop naturally without prior knowledge of their exact strength or position. Although the solutions yield a complete definition of the flow field, the primary aim is to produce airfoil surface pressure distributions for the design of aerodynamically efficient turbine blade contours. In order to demonstrate the accuracy of this method, computed airfoil pressure distributions have been compared to experimental results.

Commentary by Dr. Valentin Fuster
1971;():V001T01A090. doi:10.1115/71-GT-90.
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The development of BORSIC®-Aluminum fan blades for elevated temperature application in gas-turbine power plants has been successfully demonstrated. These fan blades are over 40 percent lighter than the titanium blades currently in use. In addition, the high modulus of the reinforcement allows fan blades to be designed without partspan shrouds which will result in a 1 percent increase in fan efficiency. A full set of blades (36) fabricated by diffusion bonding were assembled in a rotor and tested in an aeromechanical rig with both a clean inlet and a distortion inlet at ambient inlet temperature as well as with a heated inlet to produce a blade temperature of 430 F. Total running time was 30.3 hrs, eight of which were at or above design speed. The rig ran for 0.5 hrs at design speed with a blade temperature of 430 F. No severe vibratory stresses were encountered with either a clean inlet or a 2E distortion screen.

Commentary by Dr. Valentin Fuster

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