bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection of a High-Efficiency Regenerator for Pipeline Gas Turbines
Authors: Parker K. O.
Published: April 2015

The dramatically rising cost of hydrocarbon fuel in recent years has reemphasized industry attention to high thermal efficiency for its pipeline compressor drive gas turbine engines. The advent of a new stainless steel plate-fin industrial regenerator has made possible greatly improved gas turbine thermal efficiency, compact installation, and long life. The selection of the optimum match of regenerator effectiveness and pressure drop with engine characteristics is discussed together with the size and cost impact of these parameters. New design features are developed that ensure historical regenerator problems are handled effectively.
Radical Overshoot Phenomena in Liquid Fueled Gas Turbine Combustors
Authors: Kollrack R. , Aceto L. D.
Published: April 2015

A detailed analysis is presented of the processes involved in the production of NO during the combustion of liquid fuels in gas turbines. With O and OH concentrations in excess of the equilibrium values the NO production rate displays a temporary overshoot within the primary combustion zone residence time. The contributions of temperature and reaction kinetics to this overshoot are assessed. This overshoot is strongly dependent on equivalence ratio and on pressure, with the minimum overshoot occurring at ϕ = 0.9. It increases more strongly for richer than for leaner combustion. Increasing drop size at lean or stoichiometric conditions tends to retard and diminish the overshoot of the NO formation rate while increasing its duration. At rich conditions, however, increasing drop size can cause overshoot increases. Changing degrees of premixedness for a given drop size, produces a timewise shifting of this overshoot. An assessment is made of the influences and interrelation of drop size distribution, degree of premixedness and staged fuel addition.
The Spill Control and Recovery Valve: A New Concept for Reducing Fuel Temperatures and the Cost of Ownership of Gas Turbine Control Systems
Authors: Turner H. G. , Shube E. E.
Published: April 2015

Fuel provides a convenient and effective means of cooling engine and airframe equipment and it is important that its coolant capability is maximized for present and projected aircraft. The Spill Control and Recovery Valve (SCRV) is a new simple concept, patented and developed by Plessey Aerospace with support from the British Ministry of Defense, which contributes towards the realization of this objective. The SCRV is installed in the fuel system in place of the conventional bypass valve. It is a variable geometry ejector in which the energy in the spill flow (primary) is used to raise engine pump inlet pressure (secondary) whenever bypassing occurs. The maximum gain results during maximum bypass mode which is when it is most needed. Test data for certain conditions characteristic of a large civil bypass engine show: High pressure fuel pump pressure rise reduced, 27–31 percent; Fuel temperature rise reduced, 17–19 percent; Fuel heat sink capacity increased, 2.3–3 kw, NPSH increased, substantial. Relative figure has no significance. Results can be even more significant for engines in high performance combat aircraft.
Optical Detection of Blade Flutter
Authors: Nieberding W. C. , Pollack J. L.
Published: April 2015

A joint Air Force-NASA flutter research program using full-scale turbine engines is being conducted at the NASA Lewis Research Center. The initial phase is a fan flutter program using a YF-100 turbofan engine. In these tests, dynamic strain gages mounted on rotor blades are being used as the primary instrumentation for detecting the onset of flutter and defining the vibratory mode and frequency. Optical devices however are being evaluated for performing the same measurements as well as providing supplementary information on the vibratory characteristics. Two separate methods are being studied: stroboscopic imagery of the blade tip and photoelectric scanning of blade tip motion. Both methods give visual data in real time as well as video tape records. The optical systems will be described and representative results will be presented. The potential of this instrumentation in flutter research will be discussed.
Noise Reduction Potential for the Existing Business Jet Fleet
Authors: Galloway W. J. , Wilby J. F. , True H. C.
Published: April 2015

The business jet fleet registered in the United States as of July 1975 consisted of approximately 1500 aircraft, of which only 10 percent were powered by new, medium bypass ratio turbofan engines, and 75 percent by turbojet engines. A review of the noise reduction potential for existing aircraft has been completed on a model-by-model basis. An optimal combination of flight operational procedures and noise suppression techniques for existing engines has been derived for each aircraft model to minimize noise levels at FAR 36 certification measurement locations, consistent with existing noise control technology and operating economics. The alternative of new engine installations has also been evaluated. Comparisons between noise levels for modified and unmodified aircraft are presented.
Experience With Gas/Steam Combined Cycle Turbines on a Natural Gas Pipeline
Authors: Wrenn K. F. , Heard T. C. , Lang R. P.
Published: April 2015

In 1967 Columbia Gas Transmission Corp. installed a 10,500-hp gas/steam turbine combined cycle unit as a compressor driver on their pipeline at Ceredo, W. Va. Then in 1970 a similar unit, rated 12,500 hp was installed in the same station. Both of these units were chosen because of their high efficiency relative to the basic gas turbines available at that time. This paper reviews the selection, installation configuration, and operating record of these units.
Computation of the Temperature Distribution in Cooled Radial Inflow Turbine Guide Vanes
Authors: Tabakoff W. , Hosny W. , Hamed A.
Published: April 2015

A two-dimensional finite-difference numerical technique is presented to determine the temperature distribution of an internally-cooled blade of radial turbine guide vanes. A simple convection cooling is assumed inside the guide vane. Such an arrangement results in relatively small cooling effectiveness at the leading edge and at the trailing edge. Heat transfer augmentation in these critical areas may be achieved by using impingement jets and film cooling. A computer program is written in Fortran IV for IBM 370/165 computer.
The Effect of a Transversely Injected Stream on the Flow Through Turbine Cascades: Part I — Flow Effects
Authors: Shrivastava K. D. , MacCallum N. R. L.
Published: April 2015

A study has been made of the flow-through turbine cascade when a transverse flow is injected into the main flow immediately in front of the cascade. A separation bubble was observed on the end-wall immediately behind the injection slot. At the suction surface end of this bubble a vortex moved into the main flow and continued downstream through, and beyond, the cascade. The effects of the separation bubble and of the vortex were observed in measurements of pressure around the blade surfaces, in boundary layer transverses on the end-wall, and in total head and directional transverses across the cascade exit.
The Effect of a Transversely Injected Stream on the Flow Through Turbine Cascades: Part II — Performance Changes
Authors: Shrivastava K. D. , MacCallum N. R. L.
Published: April 2015

This paper reports the changes in the performance of three turbine cascades when a transverse flow is injected from an end-wall into the main flow immediately in front of the cascade The cascades used the same blade profiles, but set at stagger angles of 35, 40 and 45 deg. The effects of the following other variables were also investigated — main flow inlet angle, injection jet inclination to main flow, injection jet velocity, and jet width. The performance changes were assessed by measurements of averaged stagnation pressure losses, reductions in flow capacities, measurements of secondary flows within the channel, and measurements of the exit vortex.
An Application of TF25 Gas Turbine Engine to Hovercraft Operation in Japan
Authors: Takebe F. K. , Daimon Y. , Ejima S.
Published: April 2015

This paper describes the detail story for selecting TF25 gas turbine engine for PP-15 hovercraft, the installation arrangement on board the hovercraft and the design consideration for a marine use. The paper also describes an analysis of data acquired through actual operation of passenger transport during the Okinawa Expo, from July 20, 1975 through January 18, 1976.
Problems and Operating Experiences With Gas Turbines Burning Residual and Crude Oils
Authors: Felix P. C.
Published: April 2015

This paper presents the most important problems which have to be expected when burning residuals and crudes in industrial gas turbines. Solutions for these problems are always influencing the operating costs of the powerplant. Careful economical studies should, therefore, be conducted before one or another fuel is selected. Finally, operating experiences with 14 BBC gas turbines located in Riyadh (Kingdom of Saudiarabia) burning local Khurais crude oil with turbine inlet temperatures of 650 to 850 C are presented.
Operating Experience on Residual Fuel Oil With a W251 Combustion Turbine
Authors: DeGreef J. L. , Maes P. , Johnson K. W.
Published: April 2015

This paper describes the actual operating experience of a current technology combustion turbine, burning residual fuel, operating under actual utility conditions. The objective of the program was to demonstrate that combustion turbines utilizing air-cooled blades and vanes were capable of performing in an economical, reliable and satisfactory manner to meet the demands of a utility company in normal daily cyclical duty. Included in the program was an evaluation of a fuel treatment plant with associated fuel-handling requirements, resistance to corrosion of numerous blade and vane alloys both with and without protective coatings, plus optimization of a turbine cleaning system to remove turbine blade path deposition.
Turbine Engine Automated Trim Balancing and Vibration Diagnostics
Authors: McTasney R. , Rio R. A. , Troha W. A.
Published: April 2015

After turbine engine is overhauled at Oklahoma City Air Logistics Center (OC-ALC) or at San Antonio Air Logistics Center (SA-ALC), it is run in the test cell before shipment. While in the test cell, final adjustments are made to the engine. One of these adjustments is the dynamic vibration balance of the engine. This adjustment is referred to as a trim balance. The current trim balance procedures in use at OC-ALC require the engine to be in the test cell from 4 to 6 hr. This paper presents a new automated procedure which has demonstrated a reduction in test cell time by 60 to 80 percent. In addition, engines which cannot be trim balanced must be returned to the overhaul line for partial disassembly and rework. The diagnostic guidance provided to the rework line is highly subjective and dependent on operator experience. Uncertain problem definition often results in rejecting the same engine several times. The new procedure described in this paper shows promise for automating vibration diagnostics. This would allow definitive guidance to be provided to the rework line and reduce repeated rejects of the same engine. The Automated Trim Balancing and Diagnostic Systems as designed for OC-ALC and SA-ALC have a projected multi-million dollar savings for the Air Force.
A Quasi-Three Dimensional Analysis of Choking Flow for Radial Gas Turbines
Authors: Nakase Yoshiyuki , Fukutomi Junichiro , Inubushi Masanobu , Watanabe Takashi , Hama Yoshiyasu , Iwamoto Toshiaki
Published: April 2015

A quasi-three dimensional.flow analysis has previously been reported for a mixed flow impeller by one of the present authors. In the analysis, the velocity gradient method has been used in meridional plane and the rotating annular cascade theory has been used for blade-to-blade solution. In this report, the analysis is generalized to allow prediction and analysis of choking flow for a radial inflow gas turbine. Moreover, this analysis is corrected to include passage contraction effects and passage loss effects due to boundary-layer growth. The efficiency and choking flow rate of gas turbine may be obtained in a single computer run without the complicated throat area estimation. Some numerical examples for a burst furnace gas energy recovery turbine are presented.
Grid Connected Electrical-Thermal (Cogeneration) Energy System for University of California, Davis, California
Authors: Martineau C. , Boyen J. L.
Published: April 2015

The energy system described represents the latest technology in on-site grid-connected systems for the power range used. The electrical portion of the system consists of a liquid fuel fired gas turbine driving a 3-MW alternator which is connected into the utility system. The gas turbine is supercharged to 12 in. w.c. It is planned to operate the turbine-generator at full load continuously, thereby securing operation at the optimum fuel rate. Heat is recovered from the gas turbine exhaust by a novel heat recovery boiler utilizing a controlled economizer. Steam is generated at 150 psig and is fed into the campus steam system for heating, air conditioning, and other uses. Steam rate is 20,300 lb/hr to a final stack temperature of 308 F. Additional heat is recovered from the turbine oil cooler, the alternator cooling air, and the boiler’s continuous blowdown. The combination of electrical power generation and heat recovery from the above sources produces an overall plant efficiency of 83 percent.
Second-Generation Integrated Coal Gasification/Combined-Cycle Power Systems
Authors: Carlson N. G. , Robson F. L. , Westmoreland J. S. , Talbert W. M.
Published: April 2015

This paper discusses the second-generation integrated coal gasification /combined-cycle power systems using, as a basis, the molten-salt gasifier. A brief description of The major equipment which forms the basis of the power plant, the analysis identifying the operating conditions for the integrated system, and a discussion of the overall power plant design are given.
Synthesis of Blade Flutter Vibratory Patterns Using Stationary Transducers
Authors: Kurkov A. , Dicus J.
Published: April 2015

Flutter frequency was determined and rotor vibratory amplitude and phase distributions during flutter were reconstructed from stationary aerodynamic type measurements. A previously reported optical method for measuring blade-tip displacements during flutter was extended by means of digital analysis. Displacement amplitudes and phase angles were determined based on this method. For selected blades, spectral results were also obtained from strain gage measurements. The results from these three types of measurement were compared and critically evaluated.
Selection of Compressors and Driving Equipment
Authors: Pichot Pierre
Published: April 2015

The Gaz de France network is a combination transmission and distribution system with numerous sources, storage areas, and customers and with numerous interconnections between main lines. This nature of the network and its associated operating techniques require that special attention be given to the selection of compression equipment. This paper discusses the factors considered in this selection process and describes the method used to evaluate various equipment proposals.
Fuel Flow Elements for Automotive and Small Industrial Gas Turbines
Authors: Andrews D. K. , Smart M. W.
Published: April 2015

Requirements are defined for fuel flow control elements to be used with an electronic computer to form a flexible complete control system for a diverse range of small industrial and automotive gas turbine engines. A preferred system configuration is described, suitable for use with a variety of engine types and output powers in the 100 to 1000 kw range and for medium and high quantity production. The solution described uses a gear type fuel pump, a simple metering valve positioned by a moving coil d-c force motor, a diaphragm type pressure drop regulator, and a solenoid high pressure shut-off valve. The reasons for choice of this arrangement and its specific advantages are presented. Development and early service experience with the system are discussed and performance characteristics are presented.
The Stability of an Asymmetric Rotor in Damped Supports
Authors: Smalley A. J. , Tessarzik J. M. , Badgley R. H.
Published: April 2015

A general-purpose method of evaluating the stability of an asymmetric flexible rotor, mounted in symmetric damped bearings, is defined. This method evaluates the complex eigenvalues of the rotor system by solving the equations of motion in a rotating coordinate frame. The application of this method to a rotor mounted in tilting-pad bearings is demonstrated. The observed behavior of a number of different rotor configurations is compared with corresponding predictions of stability. For the configurations predicted to be unstable, a distinct and unnegotiable threshold of instability is encountered. The sharpness of this threshold is emphasized by careful balancing at speeds fractionally below the threshold. In a final configuration predicted to be marginally stable, lightly damped resonant behavior, negotiable by balancing, is encountered in the region of the first critical speed.
The Radial Turbine as a Ceramic Component
Authors: Panton J.
Published: April 2015

In sizes suitable for automotive gas turbines, the small radial turbine has component efficiency equal to that of the axial type, is less sensitive to the effects of tip clearance, and translates more readily into the ceramic medium with minimal aerodynamic compromise. The initial low temperature phase of a modest design and development exercise is described in which a 76-mm-dia radial turbine rotor was operated at a speed of 1670 rev/sec (100,000 rpm) and at temperature of 1000 K.
Evolution of the Turboprop for High Speed Air Transportation
Authors: Holbrook G. E. , Rosen G.
Published: April 2015

Since they first entered military and commercial service during the 1950’s, U.S.-manufactured turbopropeller engines have proved to be reliable, fuel-efficient propulsion systems for aircraft. Despite their somewhat greater mechanical complexity when comprared with turbofans, the repair and maintenance costs of the turboprops compare very favorably with those of the other types, and their substantially reduced fuel consumption and low noise level merit serious consideration for aircraft in an energy and environmentally critical future. Advancements in propeller/fan aerodynamic and structural technologies now permit flight speeds up to Mach 0.85, making turly cost-effective aircraft possible, while retaining present standards of passenger comfort and powerplant reliability.
The Role of the Recuperator in High Performance Gas Turbine Applications
Authors: McDonald C. F.
Published: April 2015

With soaring fuel costs and diminishing clean fuel availability, the efficiency of the industrial gas turbine must be improved by utilizing the exhaust waste heat by either incorporating a recuperator or by co-generation, or both. In the future, gas turbines for power generation should be capable of operation on fuels hitherto not exploited in this prime-mover, i.e., coal and nuclear fuel. The recuperative gas turbine can be used for open-cycle, indirect cycle, and closed-cycle applications, the latter now receiving renewed attention because of its adaptability to both fossil (coal) and nuclear (high temperature gas-cooled reactor) heat sources. All of these prime-movers require a viable high temperature heat exchanger for high plant efficiency. In this paper, emphasis is placed on the increasingly important role of the recuperator and the complete spectrum of recuperative gas turbine applications is surveyed, from lightweight propulsion engines, through vehicular and industrial prime-movers, to the large utility size nuclear closed-cycle gas turbine. For each application, the appropriate design criteria, types of recuperator construction (plate-fin or tubular etc.), and heat exchanger material (metal or ceramic) are briefly discussed.
Electronic Controls of Gas Turbine Engines in Fighting Vehicles
Authors: Dent J. R.
Published: April 2015

As a result of extremely low operating temperatures and the consequent starting problems of a gas turbine-engined fighting vehicle, it was decided to change the engine fuel control to an electronic system. Initial system evaluation was carried out some six years ago and the successful outcome of the tests resulted in production systems being specified a short time later. This paper describes the design development and productionizing of the fuel control system, and defines the improvement obtained in engine performance. The future trend of electronic control systems in fighting vehicles is also discussed.
Recent Developments in Sensors for the Gas Turbine Engine
Authors: Baker P. D. , Masom R. A.
Published: April 2015

A review of current technology applied to sensors for the measurement of speed, temperature, and pressure in gas turbine engines. The use of suitable materials and designs to overcome the hostile environments is discussed. The desirability of obtaining a simple interface with control systems is considered.
The Effects of Fuel Bound Nitrogen Concentration and Water Injection on NOx Emissions From a 75-MW Gas Turbine
Authors: Wilkes C. , Russell R. C.
Published: April 2015

This paper describes an investigation into the effects of fuel bound nitrogen concentration water injection rate, and operating conditions on NOx emissions from a 75-MW industrial gas turbine equipped with a currently conventional combustion system. The gas turbine was operated over the normal firing temperature range at two compressor inlet guide vane angles to determine the effect of fuel air ratio and combustor air mass flow rate on NOx yield. Number 2 distillate fuel was doped with pyridine to simulate bound nitrogen fuels ranging in nitrogen concentration from 0.01 to 0.55 percent by weight Water was injected into the combustor primary zone for NOx control at rates depending upon the firing temperature and combustor air mass flow rate. The results of over 130 test points are presented which show the effects of bound nitrogen concentration and water injection rate on the yield of NOx It is concluded that as fuel bound nitrogen concentration increases, the effectiveness of water injection in suppressing NOx emissions decreases due to the change in NOx yield and the increase in fuel flow rate. For fuels containing high levels of bound nitrogen, such as those derived from coal, it is anticipated that non-conventional combustion systems will be required if some of the current NOx codes are to be met.
Investigation Concerning Rotating Stall and Surge Phenomena Within Centrifugal Compressor Channels
Authors: Mizuki S. , Kawashima Y. , Ariga I.
Published: April 2015

Rotating stall and surge were examined by detecting mutual interference of flow patterns within each part of compressor channels. A surge was recognized in case of a larger channel volume. On the other hand, there was no surge with a smaller volume. After comparing both cases, fluctuating flow patterns were measured without the surge. Under the rotating stall condition, an unsteady fluctuating reversed flow existed at the exit of the inducer channel, but a jet and wake flow pattern disappeared downstream. When the flow rate became far lower, another reversed flow appeared at the exit of the impeller. These phenomena were in close relation to the variation of the performance characteristics of the compressor tested and also the influence of these flows upon the surge and stalls were observed to be present.
Spectrometric Analysis of Residual Fuel
Authors: Lukas M.
Published: April 2015

Fuel analysis is a critical part of fuel treatment. An accurate measurement of the contaminant level of several elements and determination of the amount of treatment and quantity of additives is required. For simple and accurate analysis of fuel contaminants, such as sodium, potassium, vanadium, calcium, and lead, the atomic emission spectrometric technique has found wide acceptance. This paper describes atomic emission, discusses analysis techniques, and points out several areas where problems may occur if the operator is not aware of them.
Compressed Air Energy Storage Turbo-Machinery
Authors: Berman P. A.
Published: April 2015

This paper presents some of the aspects involved in the selection of the thermodynamic cycle for CAES power generating systems. It also presents several of the considerations involved in fitting turbomachinery to the cycle, including arrangement and operation. A typical set of economic criteria is used to illustrate a method of cycle optimization.
Autoignition and Vaporization of No. 3 Diesel Oil Spray Under Lean Conditions
Authors: White D. J. , Cichanowicz E.
Published: April 2015

Spray or heterogeneous autoignition has recently taken on great importance with the advent of low emission (NOx) combustors requiring precise control of the primary zone equivalence ratio. Many of these combustors, particularly lean premixed systems rely on the prevaporation and mixing of the fuel and air prior and external to the primary zone combustion process. At high pressures and temperatures, heterogeneous autoignition occurs readily and it can prevent the necessary (for low NOx) premixing and prevaporization of the fuel and air. Experimental results of an investigation into the relationship between vaporization and autoignition has revealed that the necessary level of mixing and vaporization for low NOx can be achieved without autoignition for most of the present industrial gas turbine engines.
Status of Forged Turbine Rotor Technology
Authors: Billman L. S. , Walker B. H.
Published: April 2015

Low cost, forged turbine rotor technology has been under development since 1972. Several significant advancements have been made in materials and processing technology which, when applied to forged integral bladed turbine rotors, provides the opportunity to increase turbine inlet temperature by as much a 100 C. These technologies include the GATORIZING® forging process, the directional recrystallization heat treat process, and the rapidly solidified powder metallurgy process. The application of these technologies to uncooled integral bladed metal turbine rotors and to hybrid ceramic bladed rotors is discussed.
Effect of Pressure and Turbine Inlet Temperature on the Efficiency of Pressurized Fluidized Bed Power Plants
Authors: Graves R. L.
Published: April 2015

The difficulties encountered in past and present efforts to operate direct coal-fired gas turbines are substantial. Hence the development effort required to assure a reliable, high-temperature pressurized fluidized bed (PFBC) combined cycle may be very expensive and time consuming. It is, therefore, important that the benefit of achieving high-temperature operation, which is primarily increased efficiency, be clearly understood at the outset of such a development program. This study characterizes the effects of PFBC temperature and pressure on plant efficiency over a wide range of values. There is an approximate three percentage point advantage by operating at a gas turbine inlet temperature of 870 C (1600 F) instead of 538 C (1000 F). Optimum pressure varies with the gas turbine inlet temperature, but ranges from 0.4–1.0 MPa (4–10 atm). An alternate PFBC cycle offering high efficiency at a peak temperature of about 650 C (1200 F) is also discussed.
Marine Gas Turbines in the Royal Navy 1978–1979
Authors: Kingsland J. M.
Published: April 2015

The gas turbine is rapidly becoming the dominant means of propulsion in surface ships of the Royal Navy, as more ships of existing classes are built and as new gas turbine ships come into service. The paper describes recent operating experience, and the introduction of the uprated RM1 C Tyne engine to service. The principles of upkeep, engine health monitoring, and life extension being followed by the Royal Navy are discussed. The paper includes a review of the progress of the development program for the SM1 A Marine Spey engine for ships of the Royal Navy in the 1980s.
Existing Military Trainer Engine Designed to Achieve Low Maintenance Cost
Authors: Kamm K. G. , Noblat J. M. , Somers J. C.
Published: April 2015

The LARZAC 04 turbofan engine has been designed, developed and qualified by two French gas turbine engine companies linked by a controlling group known as Groupement Turbomeca-SNECMA. The LARZAC engine is in production for the Alpha Jet, a military aircraft developed by Avions Marcel Dassault-Breguet Aviation and Dornier GmbH. Teledyne CAE has an agreement to market, service and, optionally, to manufacture the LARZAC 04 in the United States and Canada and has designated this engine the Model 490-4. This paper addresses the criteria used to design the Model 490-4 and achieve high reliability and low maintenance cost. For example: (a) modular construction and how it reduces maintenance cost, (b) high reliability design and its payoff in low maintenance costs, and (c) the planned growth of the inspection intervals to achieve minimum Life Cycle Cost. Also addressed in this paper is the rugged design of the engine as proven by cyclic component tests, large and small bird ingestion, water and hail ingestion, short cycle testing and Simulated Mission Endurance Tests.
Royal Navy Experience in the Logistic Support of Marine Gas Turbines
Authors: Shaw T. R.
Published: April 2015

Spare gas turbine engines and spare parts for Olympus and Tyne Marine Gas Turbines are owned jointly by four European Navies, each of which has equal rights to draw from this common pool of spares. The Royal Navy, on behalf of all, controls the allocation of these spares to ships and also to repair. Some of the special procedures involved and problems encountered are described.
Gas Turbine Propulsion Systems for Small Naval Ships
Authors: McCoy A. W.
Published: April 2015

Analysis of gas turbine-powered naval ships of 500- to 4000-ton size has been performed for ocean escort and patrol missions with performance levels appropriate to gas turbines of both current and advanced technology. The use of gas turbine systems allows the realization of high mission effectiveness with relatively small ships. For advanced marine gas turbines, the most significant ship benefit would result from increased thermal efficiency of cruise engines by means of regenerative cycles. A secondary improvement, particularly for high dash speeds, would be the reduction of specific weight for dash engines. With such advanced gas turbines, ship sizes may be further reduced for given mission capabilities.
Turbulence Amplification in Flow About an Airfoil
Authors: Sadeh W. Z. , Sullivan P. P.
Published: April 2015

An experimental investigation of the evolution of freestream turbulence in flow about an airfoil was conducted in order to ascertain its selective amplification induced by the stretching mechanism according to the vorticity-amplification theory. Significant amplification of the streamwise turbulent energy transpired even in the limiting flow situation studied of a symmetric airfoil at zero angle of attack where the stretching is the least. Substantiation of the stretching effect was provided by the almost 100 percent amplification of turbulence with respect to its background level in the absence of the airfoil. Realization of preferred amplification at scales larger than the neutral scale of the stagnation flow was clearly indicated by the variation of the discrete streamwise turbulent energy. Particularly important was the detection of a most amplified scale which is characteristic of the coherent substructure near the airfoil stagnation zone and, concurrently, commensurate with the boundary-layer thickness.
Aerodynamics of Marine Gas Turbine Inlet and Exhaust Systems
Authors: Taylor C. A. M.
Published: April 2015

Inlet and exhaust components represent the major part of the overall gas turbine installation and can, if not correctly designed, impose severe performance penalties and risk of mechanical failure. Due to early problems, considerable research has been undertaken over the past years to understand the mechanism of complex flows in ducts of constrained shape and size to enable a “Design Code of Practice” to be established. The work has been undertaken at UK Research Establishments, and Universities, by the Ministry of Defence, Royal Navy, which has resulted in revised types of installatons in which weight, space, and costs have all been substantially reduced.
High-Temperature Particulate Removal by Moving Bed Granular Filtration
Authors: Guillory J. L.
Published: April 2015

A major problem in use of low-grade fuels for direct firing of gas turbines is particulate removal at high temperatures. Combustion Power Company has, in a multi-phase program sponsored by the United States Department of Energy, developed a continuous moving bed granular filter which has successfully operated at inlet loadings as high as 3.5 grains/ft3 (7 × 10−4 kg/m3) and temperatures above 1600 F (870 C) representative of the tertiary cleaning step in a coal-fired pressurized fluid bed gas turbine power generation system. Collection performance tests of a 2000 ft3/min (1 m3/s) pilot filter resulted in repeatable collection efficiencies as high as 99.7 percent with submicron collection above 90 percent. Design features which successfully eliminated ash pluggage are discussed.
A Statistical Investigation of Microstructure and Crack Growth in Titanium Alloys
Authors: Wilson D. A. , Hoeppner D. W.
Published: April 2015

Crack growth rates in various microstructures of Ti-6Al-4V and commercially pure titanium were studied using modified wedge opening load (WOL) specimens. Data were modeled using a Weibull four parameter survivorship function, selected because it meets the physical boundary conditions. The resulting models were exercised to determine the statistical significance of microstructure on the fatigue crack growth properties of these materials. Finally, inferences concerning gas turbine engine component design are considered.
Gas Turbine Engine Disk Retirement-for-Cause: An Application of Fracture Mechanics and NDE
Authors: Annis C. G. , VanWanderham M. C. , Harris J. A. , Sims D. L.
Published: April 2015

Historically, gas turbine engine disks are retired when they accrue an analytically determined lifetime where the first fatigue crack per 1000 disks could be expected. By definition then, 99.9 percent of these components are being retired prematurely. Retirement-for-Cause (RFC) is a procedure, based on Fracture Mechanics, which would allow safe utilization of the full life capacities of each individual disk. Since gas turbine disks are among the most costly of engine components, adopting a RFC philosophy could result in substantial systems life cycle cost savings. These would accrue from reduced replacement costs, conservation of strategic materials such as cobalt, and energy savings.
Diagnostic Development for Advanced Power Systems
Authors: Wang J. C. F. , Flower W. L. , Hardesty D. R.
Published: April 2015

The high temperatures, pressures, and particulate densities present in coal-fired advanced power systems place severe limitations on conventional probe techniques for thermometry, velocimetry, and gas and particulate analysis. Although laser-based techniques for measuring gas temperature, velocity, and composition have been demonstrated in relatively clean flame gases, little is known regarding their applicability to measurements in the product streams from coal-fired combustors. Hence, a program has been established at Sandia to develop and assess advanced physical sampling and laser-based optical diagnostic techniques. This paper describes some of the techniques under development, including a small-angle near-forward scattering optical arrangement for particle sizing and a system for making Raman-scattering measurements of gas temperature using a pulsed laser and a gated detection system. Also described here is the atmospheric combustor exhaust simulator (ACES) facility being constructed as the test bed for the diagnostic techniques.
Diagnostics and Instrumentation Requirements for Advanced Power Systems
Authors: Hardesty D. R.
Published: April 2015

A variety of advanced coal-fired gas turbine systems have been proposed for use in combined cycles for stationary power generation. The commercial acceptability of these power systems will depend upon the efficiency and reliability of the principal individual components. Strict requirements will be placed on the flow characteristics at the turbine inlet. These requirements will, in turn, impose rigid standards of efficiency and reliability on high temperature gas cleanup systems located up-stream of the turbine inlet. At Sandia, a program is underway of assessment and bench scale development of diagnostic techniques for the measurement of the properties of the high-temperature, multi-phase, turbulent flows which pertain to the working gas stream in such systems. This paper summarizes our preliminary assessment of the diagnostics and instrumentation requirements for these coat-fired gas turbine systems.
Smoke Characteristics of Distillate and Residual Fuel Burning in Gas Turbine Combustors
Authors: Liu T. M. , Washam R. M.
Published: April 2015

During the development of a rich-lean staged dry low NOx combustor, the conventional trend of increasing smoke with increasing operating equivalence ratio was found when tests were run with distillate fuel (%H = 13.0). However, when tests were run with residual fuel (%H = 11.4), the trend was reversed. In addition, when the same combustor was run with blends of distillate fuel and residual fuel, a drastic improvement of smoke was observed when only 6 percent of residual fuel was mixed with distillate fuel, and for any blending of more than 10 percent of residual fuel the combustor was practically smoke free. A chemical analysis of fuel samples revealed an appreciable amount of trace metals in the residual fuel, giving rise to the suspicion that the smoke reduction may have been due in part to these trace metals. Of these elements found, vanadium is believed to be the most likely to cause smoke reduction because of its relatively high concentration.
Non-Axisymmetric Blade Row Interaction in Axial Turbomachines
Authors: Mitchell N. A.
Published: April 2015

A three-dimensional non-axisymmetric theory is presented to analyze the interaction effects due to wakes between two blade rows in an axial turbomachine. The relative importance of potential and wake interaction with varying row separations and the contribution to the flow of shed radial and shed streamwise vorticity from the first row are examined. Numerical calculations of turbine and compressor stages are presented to illustrate the theory.
The Effect of the Axial Velocity Density Ratio on the Aerodynamic Coefficients of Compressor Cascades
Authors: Starke J.
Published: April 2015

The aerodynamic coefficients of compressor blade sections in two-dimensional flow can easily and very accurately be determined by use of the well-known Lieblein correlations. Very often the flow across the compressor blade sections is quasi-two-dimensional with the axial velocity density ratio (AVDR) differing from unity. To establish simple correlations for this type of flow as well, the AVDR effect on the aerodynamic coefficients of compressor cascades is theoretically and experimentally investigated. This results in simple but accurate formulas for the calculation of the AVDR effect on the turning angle, the reference minimum-loss inlet angle, and the losses in terms of the wake momentum thickness and the diffusion ratio.
Performance of Annular Prediffuser-Combuster Systems
Authors: Wagner W. B. , Tanrikut S. , Sokolowski D. E.
Published: April 2015

Results of an experimental investigation of the aerodynamic performance of several annular prediffuser-combustor systems are presented. Three curved wall, dump prediffusers of different length, area ratio, and turning angle were tested with and without a simulated combustor located downstream of the prediffuser performance was significantly influenced by the presence of the combustor. Pressure recovery and flow losses were determined as a function of prediffuser inlet velocity profile, flow extraction at the prediffuser inlet, axial and radial location of the combustor front end, and distribution of flow in the combustor. Axial location of the combustor was found to be the most significant parameter influencing system performance.
Advances in Labyrinth Seal Aeroelastic Instability Prediction and Prevention
Authors: Abbott D. R.
Published: April 2015

Fatigue cracking of an aircraft engine labyrinth seal occurred during pre-flight factory testing. Testing in a static rig revealed that the seal could be aeroelastically excited by the labyrinth leakage air flow. An earlier analytical model used for stability analysis was extended to account for the effect of acoustic natural frequency on the aeroelastic stability. The new model predicted that the ratio of acoustic and mechanical natural frequencies was of vital importance in determining if the nature of the pressure fluctuations within the labyrinth seal teeth provided either positive or negative aerodynamic damping to the seal. The analytical results were verified by further rig testing and also by correlation with test results for several other seals tested as part of a labyrinth seal technology program. A mechanical friction damper sleeve was designed to suppress the aeroelastic instability. The damper sleeve was tested in a rotating rig to evaluate its damping characteristics. The aircraft engine was qualified with the newly designed damper which has demonstrated its effectiveness for eight years of service and half a million hours of operation without incident.
Development and Field Experience of a New 29000 HP Gas Turbine
Authors: Hubbard J. K. , Austin C.
Published: April 2015

The paper describes the development and initial field experience with a new high efficiency 26,000/30,000 hp gas turbine. Exhaust heat from the power turbine was used to boost the installation thermal efficiency and provide icing protection for the inlet. Wherever possible, proven power turbine design concepts were combined with the advances of a “second generation” aircraft derivative gas generator to produce a reliable machine which was introduced with a minimum of development time. To assure field success, a special test facility was constructed and the unit subjected to a full load mechanical and performance test under simulated field condition.
Near Term Application of Water Cooling
Authors: Horner M. W. , Caruvana A. , Cohn A. , Smith D. P.
Published: April 2015

A joint General Electric and Electric Power Research program is nearing completion after six years of water-cooled turbine technology development. The first two years were devoted to preliminary combined gas and steam turbine cycle studies and preliminary gas turbine combustor and turbine hot section design studies. Beginning in 1976, the major emphasis has been on resolving areas of critical technology toward the application of water cooling to the heavy duty commercial gas turbine. Earlier papers, ASME 78-GT-72 and 79-GT-72, presented preliminary results for development tasks which investigated phenomena associated with application of water cooling to turbine hot section nozzles, buckets and flowpath components for operation at increased turbine firing temperature. This paper presents results obtained from mid-1978 through 1979, and deals primarily with near term application of water cooling technology to the commercial gas turbine operating on heavy residual oil or coal derived liquid fuels. Water cooling in the near term offers the promise of significant reduction of both hot corrosion and ash deposition at the turbine first-stage nozzle.
Elastomer Damper Performance: A Comparison With a Squeeze Film for a Supercritical Power Transmission Shaft
Authors: Zorzi E. S. , Burgess G. , Cunningham R.
Published: April 2015

This paper describes the design and testing of an elastomer damper on a super-critical power transmission shaft. The elastomers were designed to provide acceptable operation through the fourth bending mode and to control synchronous as well as nonsynchronous vibration throughout the operating range. The design of the elastomer was such that it could be incorporated into the system as a replacement for a squeeze-film damper without a reassembly, which could have altered the imbalance of the shaft. This provided a direct comparison of the elastomer and squeeze-film dampers without having to assess the effect of shaft imbalance changes.
Regeneration of Activated Bauxite Used as a Granular Sorbent for Removing Gaseous Alkali Metal Compounds From Hot Flue Gas
Authors: Lee S. H. D. , Swift W. M. , Johnson Irving
Published: April 2015

Gaseous alkali metal compounds transported form a pressurized fluidized-bed coal combustor (PFBC) to a gas turbine might cause hot corrosion of turbine hardware. Activated bauxite was found to be a very effective granular sorbent for use in granular-bed filters for removing gaseous alkali metal compounds from simulated hot flue gas of PFBC. Also, activated bauxite was demonstrated to be easily and effectively regenerated for reuse by a simple water-leaching process. Experimental results are presented for cyclic experiments showing the regenerability of water-leaching of activated bauxite on which NaCl vapor or KCl vapor was sorbed. Observed physical changes and particle attrition of activated bauxite as a result of regeneration are discussed. The sorption mechanisms of the regenerated activated bauxite are related to the chemical compositions of the leachate.
The Effect of Aerodynamic Phase Lag on the Twin Vibration Mode Model of Aeroengine Fan Flutter
Authors: Ford R. A. J.
Published: April 2015

An earlier paper analyzed aeroengine fan flutter in terms of twin orthogonal vibration modes in the fan. This paper extends the analysis by incorporating variable aerodynamic phase lags between a blade motion and the resulting aerodynamic forces. The extended analysis predicts two independent kinds of flutter. If the total damping within each mode is negative, each mode develops a self-sustaining vibration at its own natural frequency. This was not predicted by the earlier twin mode analysis. Even when the damping in each mode is positive an interaction between the modes can cause flutter under some conditions. This behavior is basically of the form described in the earlier paper, but there are significant detailed changes when variable aerodynamic phase lags are introduced.
Thermodynamics of Heavy Fuels Operation in Gas Turbine
Authors: Pavri R. E. , Hill J. M.
Published: April 2015

This paper discusses the effects of deposition on a gas turbine performance when operating on ash forming fuels. Parameters affected by ash deposits which cause turbine efficiency degradation are presented. Thermodynamic relationship between turbine nozzle flow area reduction, efficiency loss and firing temperature variation on two different methods of firing temperature control are derived.
Gas Turbine Inlet Air Filtration in Marine Environments: Part II — Commercial Experience and Recommended Practice
Authors: Tatge R. B. , Gordon C. R. , Conkey R. S.
Published: April 2015

The hazards associated with salt ingestion by gas turbines are discussed, and inlet air quality criteria are presented for representative heavy-duty and aircraft-derivative machines. By comparing these criteria to predicted salt levels in marine environments, it is possible to analytically identify appropriate filtration systems. These choices are shown to be compatible with commercial experience on ships, on platforms, and in coastal installations. Consequently, recommendations can be made regarding salt removal systems for marine and coastal applications.