bluuebunny/crossref_metadata_2025 huggingface dataset:
Vaned Diffuser Inlet Flow Conditions for a High Pressure Ratio Centrifugal Compressor
Authors: Verdonk G.
Published: April 2015

This paper contains a theoretical and experimental investigation of the flow in the vaneless and semi-vaneless space of a transonic radial compressor diffuser, especially for working points corresponding to the mass flow below choking values, in the efficient operating regimes. A type-dependent finite difference calculation has been developed for the inviscid flow. This method has been combined with a shock-boundary layer-interaction theory, which allows a more realistic calculation of the velocity distribution, taking into account the boundary layer variation along the sidewalls. In parallel with this analytical study, several diffuser geometries were also performance tested. A special data-reduction program allowed calculation of the throat blockage and the velocity distribution throughout the diffuser based on static and total pressure measurements. Schlieren pictures were also taken in order to have a better insight in the real flow phenomena at the diffuser entrance. From this experimental data, a detailed comparison with the analytical study was made. This combined theoretical and experimental study made it possible to show the influence of the geometrical parameters of the vaneless and semi-vaneless space on the velocity distribution, and on the throat blockage. Together with the data available in literature for channel diffusers, it allows a better prediction of the overall performances of diffuser systems.
Prospects for the Gas Turbine in the U. K. Gas Transmission System
Authors: Huggett B. M. , Austin G. J.
Published: April 2015

The paper briefly reviews the development of the U. K. natural gas transmission system over the last decade. This development has taken place in two phases. The first phase saw the building of a transmission facility, largely in England, for exploiting the gas reserves discovered in the southern north sea. The influence during this early phase of cheap fuel gas and the planned low utilization of gas compression in the selection of the gas turbine as the basic power unit for compression is discussed. The importance of minimizing the environmental impact associated with the installation of turbo-compression machinery in rural areas is stressed and the particular methods used to avoid a noise nuisance are described. The second phase of the development progressing major extensions to the transmission system in Scotland to handle the more recent gas discoveries in the northern north sea are described. The implications of rising fuel costs, energy conservation, and the changing pattern of compression operation on the U. K. systems are discussed. The future prospects for the gas turbine in the gas transmission environment are reviewed. The paper concludes that a continuing improvement in the operating efficiencies and in the reliability of gas turbine plant is required if its success in gas pumping applications is to be maintained.
Compact Metallic and Ceramic Recuperators for Gas Turbines
Authors: Förster S. , Kleemann M.
Published: April 2015

A compact plate-type recuperative heat exchanger feasible in metal or ceramic materials and suitable for stationary and vehicular gas turbines is described. The flow schemes and fabrication techniques of the heat exchanging matrices are illustrated. Metallic and ceramic prototype matrices are shown which have been fabricated successfully. On the bases of experimental heat transmission and friction data for the metallic matrices, typical design solutions are shown for complete recuperators. Design examples for metallic recuperators are given for large nuclear closed-cycle helium turbine power plants and for stationary and vehicular open-cycle gas turbines. For vehicular application, sizes for turbines of several hundred kilowatts are discussed. Two design examples are given of ceramic recuperators for a 70-kw vehicular gas turbine having small overall dimensions when compared to a piston engine. Some cost aspects of the compact recuperators are discussed. Compact metallic recuperators, such as described in the paper, may replace advantageously the tube type or other plate type recuperators for large stationary and vehicular gas turbine cycle applications. Furthermore, the ceramic compact recuperator also described in the paper may be a satisfying practical solution for small vehicular gas turbines, especially for the so-called “ceramic” gas turbines with gas temperatures at the turbine inlet of about 1300 C.
The Three-Dimensional Flow and Blade Wake in an Axial Plane Downstream of an Axial Compressor Rotor
Authors: Kool P. , DeRuyck J. , Hirsch Ch.
Published: April 2015

The three-dimensional flow field has been measured in an axial plane downstream of a low speed axial compressor rotor with a rotated single slanted hot wire. A method is described which allows one to calculate three mutually perpendicular velocity components from hot-wire data, and use is made of the technique of periodic sampling and averaging to extract the pitchwise fluctuating flow from the stationary hot-wire signals. These data contain useful information. The radial distribution of the pitchwise averaged flow variables is compared with classical pneumatic measurements and with the results of a quasi three-dimensional finite-element calculation and a three-dimensional end-wall boundary layer calculation. Finally, the wake characteristics are given and a simple correlation is presented which allows one to determine the wake velocity defect from a single wake shape factor.
Analysis of the Flow Field in a Radial Compressor
Authors: Fradin Christian
Published: April 2015

Using pressure transducers and hot wire anemometers, the flow and pressure field in a subsonic centrifugal compressor is analyzed. Detailed pressure, velocity, and flow angle maps are given for the compressor inlet section, along the shroud, in the outlet section of the rotor, and also in the vaneless diffuser. These measurements show how flow heterogeneities are generated in the compressor and how they decay in the vaneless diffuser.
Bypass Control of Closed-Cycle Gas Turbines
Authors: Krey G.
Published: April 2015

The layout of the bypass control system of a closed-cycle gas turbine depends on the steady and nonsteady part-load behavior of the plant. In the paper, the results of investigations into the operating behavior of closed-cycle gas turbines are summarized. From these a method of laying out the bypass valve is deduced. Finally, an advanced bypass control system is described and the control behavior achievable therewith is explained.
A High Temperature Turbine Research Module
Authors: Morris A. W. H. , Waldren N. E. P.
Published: April 2015

Increasing engine cycle pressure ratios and temperatures, and assuring improved component reliability and life, have led to complex blade cooling systems which, in part, compromise the aerodynamic design of today’s high pressure (HP) turbines in aero engines. The National Gas Turbine Establishment is currently constructing a new research module, and associated plant and services, to investigate the performance of cooled HP turbines. The unit will satisfy the requirement to measure the power developed by high temperature turbines when operating in an engine environment with all the cooling flows properly represented and monitored accurately. Research on the thermal design of rotor blade cooling systems will also be undertaken at realistic temperatures, pressures and turbulence level, and with correct rotational effects. The module is instrumented extensively to determine mainstream, coolant and leakage flow characteristics, and the power will be absorbed by a dynamometer connected through a torquemeter. Data on the rotor blade metal temperature, surface pressure, and coolant pressure and temperature will be transmitted via telemetry and rotating scanivalve. Data acquisition and control for the high temperature research module will be by the use of a mini computer-logger system. This paper outlines the concept and design considerations of the high temperature turbine research module. The instrumentation of the module is also presented and discussed.
Ten Years’ Engineering Development in Gas Turbine Driven Natural Gas Compressor Stations
Authors: Hondius H. , Meyer R. H.
Published: April 2015

The first generation gas compressor stations for N.V. Nederlandse Gasunie was designed in 1967 and equipped with aircraft derivative gasturbines of 11 MW driving single wheel centrifugal compressors. In later stations, similar machines and also industrial type gas turbines of 11 and 26 MW have been installed. With the system now including eight stations. a considerable experience was gained. Special described items are: (a) air filtration (b) noise abatement, (c) vibration due to pipe resonance, and (d) also the operational experience with aircraft derivative gas turbines compared with industrial type machines is described. During 1974, due to the increase in the energy prices, more emphasis was placed on energy savings. Studies revealed that for our case, the new generation high efficiency gas turbines showed more advantage than equipping existing machines with available recuperators or waste heat boilers and steam turbines. Replacement of some base load machines began in 1975. Later, a new recuperator was designed together with a well-known boiler firm, the first of which will come in operation by the end of 1978 to improve the efficiency of a 26-MW machine. Medio 1978 a total of 35 units with 502.2-MW output will have been installed, of which five are equipped with high efficiency drivers.
Rapid Positive Load Changes by Gas Injection in Closed Gas Turbine Cycles
Authors: Frutschi H. U.
Published: April 2015

Spontaneous response to power demand is essential during autonomous operation of power plants. In this case, only control principles with negligible negative momentary effects can be employed. A further requirement is a good part-load efficiency. After a brief description of the most important control methods of closed-cycle gas turbines, the dynamic behavior of the cycle during gas injection for positive load changes is analyzed. A very attractive method is inter-compressor injection from an intermediate pressure reservoir which can be charged from the compressor exit during load reduction. Based on these results, a control system for closed-cycle gas turbine employing gas injection is presented.
JETFOIL In-Service Experience
Authors: Fleishman L. A.
Published: April 2015

This paper describes the in-service experience of the Boeing Model 929 JETFOIL, an advanced commercial hydrofoil. The overall ship configuration and operation are described briefly as are the various functional systems. Unique features are described in more detail. The support program and experience to date of the JETFOIL fleet is provided along with a description of the early operational problems and how they are being corrected.
Jet Curtain Flameholder for Aircraft Afterburners
Authors: Sridhara K. , Chidananda M. S. , Paranjpe P. A.
Published: April 2015

The similarity of flow behind V-gutter flameholders and the proposed jet curtain flameholders has been demonstrated from flow visualization studies. The effective blockage of jet curtain flameholders can be varied by varying the jet pressure ratio. The jet curtain flameholder gives the same stability limits as the V-gutter if the mixture strength in the recirculation zones is identical, while it has negligible cold pressure loss. Thus, the use of the jet curtain flameholder offers the possibility of significant reduction in overall weight of an aircraft for a given range, if the afterburning duration is short.
An Investigation of Turbine Erosion by Combustor Generated Carbon in a Light Weight Marine Gas Turbine
Authors: Russell R. J. , Witton J. J.
Published: April 2015

A study has been made of the turbine erosion problem encountered in a marinized aero gas turbine which arose from the change of fuel type necessitated by the marine application. The work has involved the development of a technique for collecting carbon shed from the combustion chamber under engine operating conditions. Tests using the collector were made with a single combustor test rig and compared to engine experience. Combustion chamber modifications were developed having low solids emissions and their emissions characterized using the collector. The data from the collector show that smaller particles than hitherto collected can produce significant long-term erosion and that reduction on both size and quantity of particles is necessary to reduce erosion to acceptable levels. The data obtained in this study are compared with other published information on the basic erosion process and erosion in gas turbines by natural mineral dusts. The implications of the results to current and future engines are discussed.
A Digital Fuel Control System for Gas Turbines
Authors: Harrison P. G.
Published: April 2015

In 1975, at the ASME Conference, M. L. G. Hill of HSDE Limited, presented a paper showing the way ahead into digital control, using the new technology made available by the arrival of the microprocessor. This paper two years after describes the implementation of those concepts into economically viable designs and some techniques used to optimize the performance.
Utility System Planning Effects on the Economic Merit of Advanced Combined Cycle Power Systems
Authors: Fraize Willard , Davis Floyd , Manning G.
Published: April 2015

Many systems studies of advanced power technologies use cost of electricity as an economic figure of merit in comparing electric power generating technologies. For this parameter to be used in comparisons among technologies, it is important to account for the variations in ways that different technologies are integrated into a utility system. These variations result from differing technology-specific characteristics and differing utility characteristics. This paper illustrates the effect of some of these variations on the economic merit of advanced combined cycle power systems relative to a conventional coal-fired steam power plant.
Performance and Cost Characteristics of Combined Cycles Integrated With Second Generation Gasification Systems
Authors: Shah R. P. , Ahner D. J. , Fox G. R. , Gluckman M. J.
Published: April 2015

The performance of combined cycle power plants integrated with advanced air- and oxygen-blown entrained gasification systems as well as with advanced oxygen-blown fixed bed gasifiers will be presented. The performance and cost of such plants using near-term gas turbine technology will be compared to the performance of conventional coal-fired steam plants with FGD. The integrated combined cycle plant appears attractive at today’s gas turbine firing temperatures. Further benefits from advanced gas turbine operating conditions on the performance and economics of such plants and the rationale for these performance trends will be discussed.
Design and Test of a 73-MW Water Cooled Gas Turbine
Authors: Caruvana A. , Rose R. S. , Alderson E. D. , Cincotta G. A.
Published: April 2015

This paper presents a preliminary design of a water-cooled gas turbine capable of operating on coal derived fuels and producing 73 MW when burning low Btu coal gas. Particular emphasis is placed on the critical technology issues of combustion and heat transfer at 2600 deg firing temperature. The recent technology developments; i.e., materials developments, composite construction, water cooling, fuels cleanup, etc., which now make this advanced concept possible are discussed. Detailed descriptions of the hot gas path components, the staged sectoral combustor, the water cooled nozzles and buckets, are described showing the implementation of these recent developments. The component development test program which is underway, is described and where testing results are available, design confirmation is demonstrated. Future plans for the construction of a full scale prototype machine and for design verification testing are presented. An analytical evaluation is included which demonstrates the advantages of the water-cooled gas turbine in an integrated gasification combined cycle.
The Development of the Quick-Start Gas Turbine Standby Generator Set
Authors: Fujikawa Y. , Nakanishi K. , Kanegae H. , Sakaki Y.
Published: April 2015

A simple, relatively low-cost, two-shaft gas turbine has been developed for industrial use. It is a modification of the two-shaft regenerative vehicular gas turbine that was previously developed and has a variable power turbine nozzle. A standby electric power generator set that is powered by the gas turbine has also been built. Its rated output is 300 ps and it generates 200 kw of electrical power. As it is a two-shaft gas turbine, it requires only 9 seconds to start with a 3.5-kw electric starting motor. While the transient responses, especially in the area of speed changes caused by step load changes, appear to be an inevitable shortcoming, they have been minimized by the reduction of the gasifier rotating unit’s polar moment of inertia and other improvements in the fuel control system and units. Consequently, the use of this generator set for general purposes will not pose any problem.
Design of a Successful Low Emissions Burner
Authors: Lewis G. D. , Holladay T. E.
Published: April 2015

In anticipation of Government regulations on the emission of nitrogen oxides from industrial gas turbine engines, United Technologies Corporation has tested a burner for the FT4 engine which meets the proposed regulation of 75 PPMV NOx at 15 percent oxygen and 25 percent thermal efficiency. The design is based on predicted values of NOx as a function of flame temperature and verified the predictions. A two-phase combustion system is employed to provide the fuel-air ratio range required for engine operation without exceeding high flame temperature or lean flammability limits. A cast, finned construction is employed for durability and low cost. Current market economic considerations have required the program to be suspended.
Gas Turbine Information and Control System
Authors: Johnson D.
Published: April 2015

A distributed microcomputer system is being developed so that eight gas turbine generators can communicate over simple serial “party” cables to computers located in a central control room. There, the Station Operator’s Console gives an operator full control over the turbines, while presenting status and annunciator information on two CRTs. Redundant microcomputers inside this console drive two “party” cables for improved reliability. These microcomputers interface through telemetry equipment to the system dispatch center 60 Km from the turbine site, completing a command sequence for eight turbines in 2.5 sec. When the system is not processing commands, it collects data for the maintenance minicomputer. Over 200 signals from each turbine generator are used to create a significant data base on dual disk drives. The maintenance computer generates several logs, condition analyses and plots to support diagnostic and maintenance messages.
The Design of a Solar Receiver for a 25-KWe Gas Turbine Engine
Authors: Greeven M. , Coombs M. , Eastwood J.
Published: April 2015

This paper describes a solar receiver under development for the Department of Energy under contract to the Jet Propulsion Laboratory. The receiver is designed to be used with a single-point-focus, parabolic concentrator. The receiver accepts the concentrated solar radiation and uses it to heat the working gas of a small, open-cycle gas turbine to about 1500 F (815 C). The receiver employs a high-efficiency, metallic plate-fin heat transfer surface to effect this energy transfer. The paper discusses the thermal and mechanical design features of the receiver.
2.5-MWe Coal-Fired, Atmospheric Fluidized Bed, Recuperated Closed Gas Turbine Electrical Power Generating Plant
Authors: Harper A. D.
Published: April 2015

The ability of small utilities to meet future customer requirements for fairly priced and reliable electric power will depend on their capability either to purchase inexpensive electric power from larger utilities or to produce power from their own high-efficiency generating systems. In the not too distant future, small utilities will also be faced with the reality of burning coal. In order to help meet these future needs, The Garrett Corporation, in conjunction with the Electric Power Research Institute (EPRI), conducted a conceptual design study to evaluate the suitability of high-efficiency gas turbine engines for external firing with a multifuel (including coal) combustion heat source. A primary goal was to synthesize a system that could be placed on the market by 1985 with normal (but not accelerated) R&D funding.
Boundary Layer Studies on Highly Loaded Cascades Using Heated Thin Films and a Traversing Probe
Authors: Oldfield M. L. G. , Kiock R. , Holmes A. T. , Graham C. G.
Published: April 2015

In the continuing quest for increased turbine efficiency, the part played by blade profile shape remains crucial. Three turbine vanes with successively increased aerodynamic loading were tested in the High Speed Cascade Wind Tunnel at DFVLR Braunschweig. In addition to wake traverses, measurements of the boundary layer behavior were made. These consisted of: a) use of a constant temperature anemometer to measure the fluctuating heat transfer rate on an array of thin film platinum thermometers deposited on the vanes and b) a flattened, traversing pitot probe held against the vane surface. Transition measurement by these techniques is described.
The Combined Effect of Axial Velocity Density Ratio and Aspect Ratio on Compressor Cascade Performance
Authors: Stark U. , Hoheisel H.
Published: April 2015

The paper describes theoretical and experimental investigations on the combined effect of axial velocity density ratio (AVDR) and aspect ratio (AR) on compressor cascade performance in incompressible and compressible flow. The results presented demonstrate that it is the aspect ratio that defines the axial velocity distribution through the cascade at a given wall shape and contraction ratio. It is further shown that it is, in turn, the axial velocity distribution that decisively determines the local values of pressure distributions as well as the cascade overall parameters like turning angles and loss coefficients.
An Investigation of Vane-Island Diffusers at High Swirl
Authors: Rayan M. A. , Yang T. T.
Published: April 2015

The results of an experimental investigation of the performance of vane-island diffusers at high swirl [λ=10] are presented in this paper. Five different sets of vane-island designs and their corresponding performance are reported, and this study indicates that the performance of the vane-island diffuser depends to a significant degree on the mechanism of flow at the impeller exit. The investigation also shows that the radial distance from the vane leading edge to the impeller exit is one important factor in diffuser effectiveness. The lowest loss coefficient obtained was achieved when the vane-island leading edge was at a radius approximately equal to 1.2 times the diffuser inlet radius, and with the ratio of diffuser exit area to impeller exit area approximately equal to 1.
Blade Tip and Knife Edge Rub Testing of FELTMETAL® Seals
Authors: Tolokan R. P. , Erickson A. R. , Frank R. T.
Published: April 2015

A rub test program was conducted using Brunswick’s high speed rub rig to determine the independent effect of density and tensile strength on the abradability of FELTMETAL® seal material and to determine the optimum parameters for specific seal products. A series of 29 tests, 0.020 in. deep (0.5 mm) 360-deg rubs, were conducted on the inner air seal (knife edge) configuration with Hastelloy × and Haynes 188 seal material. Fifteen tests were conducted on the outer air seal (blade tip) configuration with seal materials of the same alloys. The program demonstrated that ultimate tensile strength rather than density is the predominant factor in determining abradability for the fiber metal system. Maximum tensile strengths were reduced and tighter density and tensile ranges were specified for four FELTMETAL® seal products to provide acceptable abradability for 360-deg rubs while maintaining erosion resistance.
High-Temperature, Coal-Fired Combustor With Ceramic Heat Exchangers for CCGT Systems
Authors: Carpenter H. W. , Campbell J. , Russell L. H. , Wright D. E.
Published: April 2015

High-temperature, coal-fired combustors with ceramic heat exchangers were designed for CCGT systems. The objective in evaluating CCGT systems is to convert U.S. coal to electricity with higher efficiency. Higher temperatures are required to accomplish this goal and ceramic heat exchanger surfaces allow the use of working fluid temperatures to 2500 F and higher. The results of a comprehensive government study are described in which an atmospheric fluidized bed and cyclone fired combustor/heat exchanger were designed for operation at 1750 and 2250 F.
Coal-Fired, Closed-Cycle, Gas Turbine Cogeneration Systems
Authors: Campbell J. , Lee J. C. , Wright D. E.
Published: April 2015

Cogeneration systems capable of utilizing our abundant coal resources are now especially attractive, as petroleum products are relatively expensive. However, coal-fired systems must inevitably cope with the abrasive and fouling character of the noncombustible ash content of all coals. This paper discusses the characteristics and cogeneration potential of the coal-fired, closed-cycle, gas turbine system (in which the working fluid is isolated from the products of coal combustion). Many closed-cycle, gas turbine thermodynamic cycles may be adapted to cogeneration. Parametric performance data are presented. The advantages of closed-cycle, gas turbine system/cogeneration cycles are explored, and comparisons are made between such systems and the more conventional steam-turbine based cogeneration cycles. The technology of closed-cycle fired heaters, including pulverized coal and fluidized bed firing is discussed. The key technical features of the fired heaters are discussed.
Coal Gasification/Repowering: A Means of Increasing Plant Capacity While Reducing Oil Consumption
Authors: Lehman S. J. , Giramonti A. J. , Meyer R. H.
Published: April 2015

An exploratory study was carried out by the United Technologies Research Center and Northeast Utilities Service Company to identify the performance characteristics of power plants based upon the repowering of several existing steam plants. In steam station repowering, an advanced, high temperature gas turbine fired by coal-derived, low-Btu fuel gas would generate power and exhaust to a new waste-heat recovery boiler that replaces the old oil-fired steam boiler. Steam from the new boiler drives the existing steam turbine. Computer models were assembled to simulate the integration of molten salt and Texaco coal gasification systems with combustion turbomachinery representative of the 1990 time frame. The results of this study indicated that either coal gasifier in a combined-cycle repowering application appears attractive as a means of replacing oil-fired systems with coal.
Industrial AFB-Fired Gas Turbine Systems With Topping Combustors
Authors: Marksberry C. L. , Lindahl B. C.
Published: April 2015

An Atmospheric Fluidized Bed (AFB) combustor providing thermal input to gas turbines is a promising near-term means of decreasing national premium fuel consumption, in an AFB many solid fuels, including marginal fuels such as anthracite culm, bituminous gob, high sulfur coals, lignite, and petroleum coke, can be used effectively providing both very low emission levels and acceptable return-on-investment. This paper discusses the state of AFB/gas turbine cogeneration technology with reference to typical industrial plant applications. Design considerations and design limits for both the AFB heat exchangers and the topping combustor are discussed and compared. An example based on plant process data and commercially available components is also presented. Both the heat exchangers and the combustors are viewed with reference to state-of-the-art technology.
Gas Turbine Inlet Air Filtration in Marine Environments: Part I — Marine Aerosols and Equipment for Their Control
Authors: Tatge R. B. , Gordon C. R. , Conkey R. S.
Published: April 2015

The chief mechanisms by which salt is introduced into marine air are examined, and the quantity and character of the salt are related to environmental conditions, height above the sea, and distance inland from the shore. Characteristics of commercially available moisture separators are described, and statistical descriptions of salt levels are calculated for representative applications.
Evaluation Method for Closed Cycle Gas Turbines in Cogeneration Applications
Authors: Daudet H. C. , Trimble S. W.
Published: April 2015

The utilization of coal-fired closed cycle gas turbine/atmospheric fluidized bed (CCGT/AFB) electrical power generating plants for cogeneration was investigated in a Department of Energy-sponsored study program conducted by The Garrett Corporation. Both industrial process and district heating and cooling applications in the 10- to 50-MWe range were considered. An evaluation procedure was developed in which cogeneration plant capital, operating, maintenance, and financing costs are calculated and compared with the cost of providing equivalent services by traditional methods. Computer optimized conceptual designs of the CCGT/AFB plants were prepared, and performance and capital costs were estimated. A broad spectrum of applications including towns, military bases, universities, and industrial processes was surveyed. This paper presents the general evaluation procedure, typical plant designs, and the evaluation of two applications.
CF6 Fan Performance Improvement
Authors: Patt R. F. , Reemsnyder D. C.
Published: April 2015

A significant portion of the NASA-sponsored Performance Improvement Program for the CF6 engine was the development of an improved fan concept. This involved aerodynamic redesign of the CF6 fan blade to increase fan efficiency while retaining the mechanical integrity, operability, and acoustic characteristics of the existing blade. A further improvement in performance was obtained by adding a fan case stiffener ring to decouple blade-case vibrational characteristics, permitting a significant reduction in running tip clearance. Engine testing was performed to establish the performance, mechanical and acoustic properties of the new design relative to the current fan, and to establish power management characteristics for the CF6-50C2/E2 engine. A significant improvement in cruise power SFC of 1.8 percent was demonstrated in Sea Level testing projected to altitude flight conditions. The improved fan has been certified in the CF6-50C2/E2 engines and is now in commercial service on the Boeing 747, Douglas DC10-30 and Airbus Industrie A300B aircraft. The improved fan will also be incorporated in the CF6-6K engine and provides a basis for further improvements that will be incorporated in other General Electric commercial offerings, such as the CF6-80 and CF6-32.
Some Unique Gas Turbine Problems
Authors: Bultzo C.
Published: April 2015

Exxon’s Baytown Refinery fired its first gas turbine in July of 1958. At the present time, there are seven generator sets, totaling 120 megawatts, and five process drivers, totaling 38,000 hp inservice. Because of the critical nature of one process, we have installed a 100-percent spare backup gas turbine and compressor. The topics that will be discussed in this paper are those experienced during the last 25,000 hr of more than 180,000 hr of operation. None of these problems were catastrophic in nature but were new to our complex. Hopefully, this discussion will provide other users of gas turbines some insight.
The Compound Heat Pump Gas Turbine: An Approach to Energy Conservation for Process Industries
Authors: Fejer A. A.
Published: April 2015

Operating on a combined Brayton and reversed Brayton cycle, this single-shaft engine, utilizing a single compressor for both parts of the cycle, develops simultaneously shaft power, process heat, and refrigeration in prescribed ratios. The engine is described here in terms of a schematic diagram and of analytical performance data covering a range of engine cycle parameters. An illustrative example shows the potential fuel savings obtainable with such an engine in a medium-size meat packing plant.
Experience in Extending the Life of Gas Turbine Blades
Authors: Liburdi J. , Stephens J. O.
Published: April 2015

This paper presents the effects of deterioration of gas turbine blade life with prolonged service exposure. This deterioration is primarily due to internal microstructural changes and the formation of creep voids or cavitation. Methods of evaluating residual blade life or life trend curves are presented along with a documentation of the creep damage observed. The extension of blade life by Hot isostatic pressing versus reheat treatment is discussed and data is presented to show that complete recovery of properties can be achieved even after the material has suffered extensive internal creep damage. As a result, the time between overhauls for blades can be significantly extended, and the need for replacement blades can be minimized.
Wood Burning Indirectly Heated Gas Turbine/Cogeneration System for Use in the Pulp and Paper Industry
Authors: Mills R. G. , Peltier R. V.
Published: April 2015

The gas turbine or Brayton cycle offers many advantages over a conventional power plant, especially when installed in a cogeneration mode. These advantages include physically compact packages, high reliability, improved system economics and full operating flexibility to meet variable electrical/steam demand. Until recently, the primary disadvantage of the gas turbine cycle has been that internal burning of dirty fuels caused unacceptable erosion and corrosion of turbine blading. In the simple cycle gas turbine modified for indirect heating, the compressor discharge air passes through the tube side of a heat exchanger before passing on to the turbine. Heat is transferred to the air via the combustion products of alternative fuels passing through the shell side of the heat exchanger. This paper discusses the potential of the indirectly heated gas turbine burning wood in a cogeneration configuration with a back-pressure steam turbine.
Analysis of Rotating Stall in Vaneless Diffusers of Centrifugal Compressors
Authors: Abdelhamid Amr N.
Published: April 2015

Self-excited flow oscillations in radial vaneless diffusers of centrifugal compressors are investigated analytically using the linearized equations of motion for unsteady flows. Solutions of the differential equations are made to satisfy boundary conditions at diffuser inlet and exit which in typical conversion systems represent the coupling between the diffuser and upstream and downstream components. The results indicate that the rotational speed of the stall pattern is dependent on the diffuser radius ratio and the coupling conditions between the impeller and the diffuser. It is shown that the dependence of the onset of the flow oscillations on the diffuser radius ratio is strong if the conditions at diffuser inlet are such that low speed rotating stall patterns are generated in the diffuser. Onset of high speed rotating stall patterns is more affected by the coupling conditions between the impeller and the diffuser than by the diffuser radius ratio.
A Cost Effective Engine Health Monitoring System for On-Board Use on Hovercraft
Authors: Karanjia D. J. , Saravanamuttoo H. I. H.
Published: April 2015

Hovercraft operate in a very hostile environment, subject to continuous spray conditions. In salt water or dusty environments, this can lead to rapid engine performance deterioration. The need for a cost effective Engine Health Monitoring (EHM) system operable by the crew, preferably on-board, clearly existed. Such a system was developed for the Bell Aerospace Canada Voyageur hovercraft making use of only existing engine instrumentation in conjunction with a programmable calculator. This approach was readily accepted by both craft operators and maintenance personnel, and has demonstrated the ability to detect engine problems before severe damage occurs.
Development of a Coal Fired Pressurized Fluidized Bed for Combined Cycle Power Generation
Authors: Moskowitz S. , Weth G. , Leon A.
Published: April 2015

A program to design, construct and operate a pilot electric plant using a pressurized fluidized bed (PFB) combustor burning high sulfur coal to produce electricity at competitive costs and in an environmentally acceptable manner is proceeding under DOE sponsorship. Three components were identified needing experimental test data to validate the selected design configurations or material selections. These components included: (a) PFB in-bed heat exchanger tubes, (b) hot gas cleanup system, and (c) turbine blades. R&D test programs utilizing laboratory rigs, commercial fluid bed reactors, and a large scale PFB technology rig were conducted for a cumulative test time of over 10,000 hr. Design criteria and configurations were selected and verified. This paper presents the results of the technology development presents the results of the technology development tests. Also, the large scale PFB technology rig design and test program are presented. The results of operating a small gas turbine coupled to the PFB combustor and hot gas cleanup system within this technology rig are discussed.
Efficient Power Generation From Large 750°C Heat Sources: Application to Coal-Fired and Nuclear Power Stations
Authors: Tilliette Z. P. , Pierre B.
Published: April 2015

Considering the concern about a more efficient, rational use of heat sources, and a greater location flexibility of power plants owing to cooling capability, closed gas cycles can offer new solutions for fossil or nuclear energy. An efficient heat conversion into power is obtained by the combination of a main non-intercooled helium cycle with a flexible, superheated, low-pressure bottoming steam cycle. Emphasis is placed on the matching of the two cycles and, for that, a recuperator bypass arrangement is used. The operation of the main gas turbocompressor does not depend upon the operation of the small steam cycle. Results are presented for a conservative turbine inlet temperature of 750 C. Applications are made for a coal-fired power plant and for a nuclear GT-HTGR. Overall net plant efficiencies of 39 and 46 percent, respectively, are projected.
Selection of a Closed Brayton Cycle Gas Turbine for an Intermediate-Duty Solar-Electric Power Plant
Authors: Vieth G. L. , Plummer D. F.
Published: April 2015

Subsystem and system analyses were performed to select the preferred working gas, performance characteristics and size of a closed cycle gas turbine for an intermediate-duty solar-electric power plant. Capital costs for all major subsystems were evaluated, but the principal selection criterion was the projected cost of electricity produced by the plant. Detailed analyses of the power conversion loop were conducted for both air and helium systems. Since the plant was intended for use on an intermediate-duty cycle, thermal storage was required. The coupling of the storage and power conversion loops in combination with the daily operating cycle influenced plant performance and energy costs in addition to the selection of the power conversion cycle. This work was done under contract of DOE as part of the Advanced Solar Electric Central Receiver Program.
Atomizing Characteristics of Swirl Can Combustor Modules With Swirl Blast Fuel Injectors
Authors: Ingebo R. D.
Published: April 2015

Cold flow atomization tests of several different designs of swirl can combustor modules were conducted in a 7.6 cm diameter duct at airflow rates (per unit area) of 7.3 to 25.7 g/cm2 sec and water flow rates of 6.3 to 18.9 g/sec. The effect of air and water flow rates on the mean drop size of water sprays produced with the swirl blast fuel injectors were determined. Also, from these data it was possible to determine the effect of design modifications on the atomizing performance of various fuel injector and air swirler configurations. The trend in atomizing performance, as based on the mean drop size, was then compared with the trends in the production of nitrogen oxides obtained in combustion studies with the same swirl can combustors.
An Aerodynamic Method for Control and Range Improvement of Rotary Compressors
Authors: Kyrtatos N. , Watson N.
Published: April 2015

An aerodynamic method is proposed to replace the variable inlet guide vanes used for imparting compressor inlet prewhirl. High pressure jets are injected obliquely into the inflow, from orifices spaced around the periphery of the inlet pipe. A mathematical model of the flow situation was developed, which considers an unbounded axisymmetric jet ejected obliquely at various angles into a cross flow. The solution for the trajectory and growth of the jet was found to be in good agreement with relevant published experimental data. Prewhirl producing jet arrangements were designed and the flow deflection resulting from the combined action of the jets was measured for a range of jet velocities and cross flow velocities.
Large, Flexible, Efficient, 750°C Closed Gas Cycle Coal-Fired or Nuclear Cogeneration Plants
Authors: Tilliette Z. P. , Pierre B.
Published: April 2015

A now unavoidable concern is the best possible use of a given energy source in order to meet the demand of power and heat. The most efficient, rational, thermodynamically satisfactory way of producing heat is to cogenerate it with power and to handle it as a by-product. Another basic condition is to supply heat without disturbing the operation of main turbogenerators. Closed helium cycle, non-intercooled, gas turbine coal-fired and nuclear power plants which meet these requirements are presented in this paper. Low-pressure steam and hot water are recovered from the precooler; medium, high pressure steam and steam superheating are generated by means of a bypass arrangement of the recuperator. The concept offers attractive overall energy conversion coefficients, very flexible heat production conditions and significant potentialities of reducing oil consumption. Results are given for the conservative 750 C gas turbine inlet temperature.
Reciprocal Efficiency Improvement of High Temperature Fossil and Low Temperature Solar Heat Sources for Power Generation
Authors: Tilliette Z. P. , Pierre B.
Published: April 2015

Gas turbine systems are investigated for solar energy conversion because they can offer satisfactory performances, particularly in case of combined cycles, and interesting solutions for plant operation. Hybrid concepts, associating solar heating with fossil firing, reduce the need for energy storage. Key problems are: matching of combined gas and steam cycles for performances enhancement, coupling of solar heating with fossil firing, use of as much solar energy as possible and priority use of solar energy at medium temperature (200/650 C), because, within this temperature range, technology is more readily available for the solar receiver system (central receiver, fixed mirror concentrators, parabolic dish collectors…) and for the primary circuit (Gilotherm, Dowtherm, sodium, molten salts…).
Experimental Evaluation of Catalytic Flame Stabilization for Aircraft Afterburners
Authors: Angello L. C. , Coppola E. N.
Published: April 2015

Catalytic flame stabilization encompasses the use of a porous catalytic surface to initiate, stabilize, and provide a continuous pilot for flame propagation. A preliminary assessment of the feasibility of employing catalytic flame stabilization to the design of flameholders for aircraft afterburners has been completed. Initial testing has demonstrsted that catalytic flame stabilization in aircraft afterburners can be achieved. For the non-optimal catalytic flameholders evaluated, smooth light-off and stable operation were obtained; higher combustion efficiencies were measured and higher pressure losses were observed. During the course of the experiment a significant number of design aspects were determined to require further investigation. These design aspects along with other results of this study are discussed in this paper.
Ongoing Development of a Low Emission Axisymmetric Annular Vortex Combustor for an Industrial Gas Turbine
Authors: Sood V. M. , Shekleton J. R.
Published: April 2015

An axisymmetric annular vortex combustor was tested atmospherically to determine the feasibility of meeting the 1977 proposed EPA emission standards for stationary gas turbines. Flame stabilization was achieved solely by swirl induced recirculation without the jet assisted recirculation of conventional practice. Buoyancy forces are used to enhance or diminish turbulent mixing. It was found that by uniformly mixing gaseous fuel and air prior to combustion and burning fuel lean it was possible to meet the proposed emission standards. The resultant narrow range of flame stability necessitated fuel staging for light-off and off-design operation. Fuel staging was achieved by stratified charge combustion (diffusion flame). Changes in combustor geometry were made and extensive traversing of the flame zone was carried out to measure concentrations of chemical species.
Droplet Burning and Evaporation Times for Distillate and Residual Fuel Oils
Authors: de Boer P. C. T.
Published: April 2015

Estimates are given of the burning and evaporation times of No. 2 distillate and No. 6 residual oil droplets, under conditions typical of industrial gas turbine combustors. Account is taken of the temperature dependence of the specific heat, the diffusion constant, and the thermal conductivity of the gas mixture surrounding the droplet. Detailed calculations are presented of the factor by which the droplet lifetime is reduced as a result of convection, for the case that the droplet is released in a gas moving at constant velocity. This factor is on the order of four for the conditions of interest. Using estimates of initial droplet diameter based on data reported by Jasuja, it is found that the ratio of characteristic droplet burning time to characteristic droplet residence time in a typical industrial gas turbine combustor is much smaller than 1 for distillate oil, but may be on the order of 1 for residual oil.
Considerations of the Use of Vitiated Preheat
Authors: Odgers J. , Kretschmer D.
Published: April 2015

It is widely held in industry that the use of vitiated heaters is to be avoided in combustion tests. The present paper reviews the situation and gives results which suggest the magnitude of the problem with respect to the various combustion test measurements. Vitiation temperatures up to 800 K are considered and the effects are assessed against: (a) gas temperatures within the combustor, (b) combustor wall temperatures, (c) flame radiation effects, (d) air/fuel distribution within primary zone, and (e) pollutant effects. It is demonstrated that some of the above effects may be minimized by using oxygen replenishment. The paper concludes that in no circumstances should vitiated preheating be used. Oxygen replenishment, whilst largely overcoming the deleterious effects of items (a) to (d) above, is not sufficient to overcome the effects upon the formation of pollutants, particularly oxides of nitrogen.
Effect of Fuel Molecular Structure on Soot Formation in Gas Turbine Engines
Authors: Naegeli D. W. , Moses C. A.
Published: April 2015

A high-pressure research combustor operating over a wide range of burner inlet conditions was used to determine the effects of fuel molecular structure on soot formation. Six test fuels with equal hydrogen content (12.8 percent) were blended to stress different molecular components and final boiling points. The fuels containing high concentrations (20 percent) of poly-cyclic aromatics and partially saturated polycyclic structures such as tetralin, produced more soot than would be expected from a hydrogen content correlation for typical petroleum based fuels. However, fuels containing naphthenes, such as decalin, agreed with the hydrogen content correlation. The contribution of polycyclic aromatics to soot formation was equivalent to a reduction in fuel hydrogen content of about one percent. The fuel sensitivity to soot formation due to the polycyclic aromatic contribution decreased as burner inlet pressure and fuel/air ratio increased.