bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Storage and Conversion Efficiency in a Hydraulic/Gas-Turbine Hybrid
Authors: Dunn H. S. , Wojciechowski P. H.
Published: April 2015

An energy storage system having a limited capacity is employed for the purposes of (a) removing the burden of acceleration from the vehicle prime mover in typical urban driving situation and (b) providing an efficient regenerative braking system to significantly increase fuel economy over stop-start driving schedules. Energy is stored in a hydraulic accumulator which is designed to be an integral part of a hydraulic transmission. Data from laboratory tests are presented to indicate achievable energy conversion efficiencies. Computer simulation of various size vehicles being driven over typical urban-suburban driving schedules is used to estimate the reduction in vehicular emissions and energy consumption resulting from the energy storage capability.
Construction and Initial Operation of a PACE Combined Cycle Power Plant
Authors: Berman P. A.
Published: April 2015

This paper describes the construction and initial operation fo a 260-MW combined cycle power generating plant consisting of two gas turbines, each with its own heat recovery steam generator. The steam, which is generated at 1200 lb 950 deg in each of the boilers, is combined to feed a single cylinder axial exhaust steam turbine. The paper describes the major components and operating cycle, the control system and some of the initial startup problems.
A Multichannel Telemetry System for Flow Research on Turbomachine Rotors
Authors: O’Brien W. F. , Moses H. L. , Carter H. R.
Published: April 2015

Flow data taken directly from turbomachine rotors are valuable, but the instrumentation problems are difficult. Information must be transferred from high-speed rotors, and the measurements require miniature transducers that can operate in high-acceleration environments. Recent advances in electronics, particularly in integrated circuitry, have permitted the design of miniature radio-telemetry systems for the transmission of data from rotors to stationary measurement equipment. Measurements are obtained without physical contact with the rotor, eliminating a principal problem. The present paper describes the design of a six-channel telemetry system for on-rotor research in turbomachinery.
Experiences With Gas Turbines Burning Non-Refined Fuel Oils and Related Theoretical Investigations
Authors: Frieder A. J. , Felix P. C. , Hess H. J.
Published: April 2015

This paper presents experience on large, low firing temperature European gas turbines operating on crude and residual fuels. The most economic fuel can be a distillate, a heavy distillate, a crude oil, and, in some applications, even a residual fuel.
The Aerodynamics of a Turbine Cascade With Supersonic Discharge and Trailing Edge Blowing
Authors: MacMartin I. P. , Norbury J. F.
Published: April 2015

This paper presents a very thorough experimental investigation of a supersonic turbine cascade with thick trailing edges designed for trailing edge ejection of cooling air. Experiments were performed on a supersonic turbine cascade designed for a deflection of 135 deg and outlet Mach number 1.2. The blade section was designed for high rates of cooling air flow, the cooling air being ejected through a slot in a relatively thick trailing edge. Results were obtained for both the blown cascade and the equivalent cascade with solid trailing edges. The flow was found to be substantially different from that assumed in the design method, the effect of reduced base pressure at the trailing edges being especially important. Theoretical considerations lead to an improved model of the flow and in particular the high total pressure loss measured experimentally is largely explained.
On the Energy Transfer in Centrifugal Compressors
Authors: Bammert K. , Rautenberg M.
Published: April 2015

In the layout and calculation of centrifugal compressors there are still considerable uncertainties when it comes to the theoretical determination of energy transfer from the impeller to the flowing medium and to the subsequent energy conversion in the diffuser. These problems arise particularly where compressor stage design with high pressure ratios and mass flow rates are concerned. A solution to these questions can presumably be found only through a physically balanced interpretation of the extremely complex flow mechanisms in the impeller. Since purely theoretical methods have hardly led to any reliable conclusions concerning the criteria of flow separation in the impeller or the secondary character of the impeller flow, there is still little knowledge about the creation of the jet-and-wake zones in the impeller and their decay (associated with large losses) in the connected diffuser. In studying the energy conversion process in the stage as a whole, great attention has to be devoted to the effects of the momentum exchange directly downstream the impeller. Hence the only possible way of solving these problems seems to be specific experimentation. For high flow velocities, this necessitates a special nonsteady measuring technique which also gives information about the relative flow in the rotating impeller.
Short Duration Studies of Turbine Heat Transfer and Film Cooling Effectiveness
Authors: Louis J. F. , Goulios G. N. , Demirjian A. M. , Topping R. F. , Wiedhopf J. M.
Published: April 2015

Short duration studies of heat transfer and film cooling effectiveness were made using a shock tunnel and a blowdown facility. In these short duration tests, flow and temperature modeling were used to determine the Nusselt number for a given set of Reynolds number, Mach number and temperature ratios representative of turbine operating conditions. Shock tunnel techniques were used to determine the isothermal effectiveness of coolant injection through slots and patterns of holes located in flat and curved surfaces. In the turbine blowdown facility, the Nusselt number at the shroud (engine seal) was determined for a wide range of operating conditions. Strong secondary flow and centrifugal effects were found to increase the Nusselt number significantly over the level associated with one-dimensional convectional heat transfer for a turbulent flow. Using shock tunnel and uncooled turbine data, a particular film cooling configuration was selected for the turbine shroud under investigation. The investigation on the film cooled stationary shroud gave encouraging results as to the applicability of two-dimensional film cooling data to the three-dimensional heat transfer at the shroud and as to the use of film cooled shrouds in advanced turbines.
A Case History on the Application and Operation of Gas Turbines and Waste Heat Boilers in a Total Energy Cycle for a Major Chemical Manufacturing Complex
Authors: Zanyk J. P.
Published: April 2015

A brief history on the application, start-up and operation of two gas turbines with waste heat recovery boilers in a combined energy cycle, integrated with an existing power plant to provide the total energy needs for a major chemical manufacturing complex. This paper describes an installation with some unique design features to provide for maximum cycle efficiency and reliability and discusses the major problems and difficulties experienced in putting this complex energy plant into operation.
The Prototype of a 100-Mw, 3000 Rpm Gas Turbine Series for Power Generation
Authors: Frigieri G. P.
Published: April 2015

This paper presents the prototype of a large gas turbine new series whose peculiar characteristics make the same very attractive for both base and peak load applications. The gas turbine engine, now in an advanced stage of manufacturing, is scheduled to be bench tested in the last quarter of the year. The major design features of the gas turbine engine together with the prototype test program are described. In addition, the peculiar characteristics of the control system and and package installation are mentioned.
The Design and Performance of Axially Symmetrical Contoured Wall Diffusers Employing Suction Boundary Layer Control
Authors: Nelson C. D. , Hudson W. G. , Yang T.
Published: April 2015

This paper presents a procedure for the design and the performance prediction of axially symmetrical contoured wall diffusers employing suction boundary layer control. An inverse problem approach was used in the potential flow design of the diffuser wall contours. The experimentally observed flow characteristics, the stability of flows within the diffuser, are also described. Guidelines for the design of low suction (less than 10 percent of the inlet flow) and thus high effectiveness contoured wall diffusers are also provided based on the results of the experimental program. Three short (L/ΔR < 5), high area ratio (3:1) diffusers, which were designed and tested, were found to have effectiveness values in excess of 90 percent (comparable straight wall diffusers have effectiveness < 40 percent). Because of their high effectiveness and short length these diffusers appear to be ideally suited for use as gas turbine combustor diffusers and as turbine discharge diffusers.
Construction and Initial Operating Experience on Two Prototype Gas Turbine Power Plants
Authors: Hoppe P. J. , Keller B.
Published: April 2015

In this paper, the authors describe construction and initial operating experience on two prototype gas turbine power plants located thousands of miles apart: Isefjordvaerket’s 140-MW plant at Kyndby, Denmark, built by Brown Boveri-Sulzer Turbomachinery (BST) and Northern States Power’s 200-MW plant at Blue Lake, Minnesota, built by Turbodyne Corporation (TBD). The paper provides a unique opportunity of comparing two approaches to a similar plant construction concept.
Theory of Rotor Dynamics With Coupling of Disk and Blade Flexibility and Support Structure Asymmetry
Authors: Klompas Nicholas
Published: April 2015

The classical theory of shaft whirling is extended to account for the third dimensional effects, due to asymmetry of support structures and flexibility of disks and blades, often encountered in modern aircraft engines. The shaft assumes a component of whipping in addition to steady whirling; the resulting elliptical motion alters the gyroscopic effect of the classical theory and introduces the possibility of coupled disk and blade vibration. A sample analysis of a model of a representative engine rotor illustrates possible drastic inadequacy of the classical theory.
A 125-Mw Unfired Combined Cycle Electric Generating Unit From Concept to Operation
Authors: O’Donnell W. J. , Schwalje P. J.
Published: April 2015

This paper discusses the development of a 125-Mw combined cycle generating unit from the original developmental concepts to the initial operation. The initial justification, the evolution of the plant through design, and the actual construction are discussed. The actual construction site and the equipment utilized are described. A discussion of the cooling system and the licensing efforts that were required are also discussed. This paper also shows how this type of plant will provide a versatile, economical, mid-range peaking plant.
Design of a 65,000-Hp Heavy Duty Two-Shaft Gas Turbine
Authors: Orsino A. J. , Gilbert K. E. , Kojima H.
Published: April 2015

This paper describes the design of a 65,000-Hp heavy duty gas turbine for marine service, for land-based mechanical drive applications and for 50 Hz power generation. Operating experience of generically similar units was used to establish the high level of reliability and maintainability incorporated into this unit. This model series gas turbine will be available for commercial application in 1974.
Diagnostic Sonics for Gas Turbine Engines
Authors: Zabriskie C. J.
Published: April 2015

Sonic analysis is very similar to vibration analysis. A gas turbine engine produces an acoustic spectrum which reflects the rotating speed and geometric relationships of the various rotating components. Additional acoustic energy is released every time a disparity or fault comes in contact with another surface. The frequency and characteristic of these signals can be used to isolate faulty components. The sonic analysis concept is based on employing narrow band filtering to separate the discrete signals from the noise components to determine signal characteristics relative to amplitude, harmonic, and modulation content. When a part or component begins to wear or go through some other physical change, the character of the acoustic signal is altered. By monitoring the characteristics of all the discrete frequencies produced by the rotating components, it is possible to detect changes in the mechanical condition and to pinpoint the individual component which is deteriorating.
A Different Approach to Gas Turbine Exhaust Silencing
Authors: Weiss Marv
Published: April 2015

A unique method for silencing heavy-duty gas turbines is described. The Switchback exhaust silencer which utilizes no conventional parallel baffles has at operating conditions measured attenuation values from 20 dB at 63 Hz to 45 dB at higher frequencies. Acoustic testing and analyses at both ambient and operating conditions are discussed.
A Review of the Bases of Predicting Heat Transfer to Gas Turbine Rotor Blades
Authors: Brown A. , Martin B. W.
Published: April 2015

This paper reviews the methods for predicting boundary-layer behavior on flat and curved surfaces under conditions experienced in gas turbine engines and the resultant heat transfer to the turbine rotor blades. Particular attention is given to the effects of streamwise pressure gradient and the intensity of mainstream turbulence on transition phenomena. The time-mean heat transfer across a boundary-layer under unidirectional oscillatory mainstream flow, such as might be initiated in a combustion chamber, is considered. The relevance of flat plate predictions and correlations to rotating turbine blades is also discussed.
Calculated Ground Level Concentration of Pollutants From Gas Turbine Using an Air Quality Display Model Computer Program
Authors: Dibelius N. R. , Touchton George , Kane Thomas
Published: April 2015

This paper contains the calculated ground level concentrations of air pollutants from 11 gas turbine models. These calculations were made using Charlotte, N.C. meteorological data. Four of these are simple cycle machines covering a range of size from 5050 hp to 65 MW and four are regenerative machines. Another three are combined cycle (STAG) machines, two machines having unfired and one having a fired heat recovery steam generator. The calculations were made using a slightly modified version of the United States Environmental Protection Agencies Air Quality Display Model Computer Program.
Objectives for a Course in Aircraft Gas Turbines
Authors: Lancaster O.
Published: April 2015

Education is similar to other endeavors in that for effective achievement there must be goals. Hence, teachers should explicitly formulate learning objectives in every course they teach. Teachers usually list only the subject matter. This should be supplemented by precise statements as to what the students are to learn. The statements should be operational. They should be expressed in action words which prescribe what the student is to do, how, and under what conditions he will demonstrate that he can do it. The establishment of objectives is illustrated by developing them for a course in aircraft gas turbines.
Gas Turbines in the Royal Navy, 1970 to 1973
Authors: Shaw T. R.
Published: April 2015

Olympus TM3B and Tyne RM1A marine gas turbines have entered service in ships of the Royal Navy. Development work on these engines, and on the uprated Tyne RM1C, over the past four years is described, together with associated work on demisters, silencers and ducting. The Royal Navy approach to gas turbine logistic support is also discussed.
Heat Treating of a Lamellar Eutectic Alloy (γ / γ′ + δ)
Authors: Tewari S. N. , Dreshfield R. L.
Published: April 2015

Eutectic superalloys are being developed at several laboratories for application as aircraft gas turbine airfoils. One such alloy γ / γ′ + δ was subjected to several heat treatments to determine if its mechanical properties could be improved. It was found that by partially dissolving the γ′ at 1210 C and then aging at 900 C, the tensile strength can be increased about 12 percent at temperatures up to 900 C. At 1040 C, no change in tensile strength was observed. Times to rupture were measured between 760 and 1040 C and were essentially the same or greater than for as-grown material. Tensile and rupture ductility of the alloy were reduced by heat treatment.
Problems of the Heat Exchanger for Vehicular Gas Turbines
Authors: Tiefenbacher E.
Published: April 2015

It is well known that a vehicular gas turbine needs a heat exchanger to compete in fuel consumption with the piston engine, especially with the diesel. A short review of the theory of heat exchange shows that very small hydraulic diameters must be used to obtain a reasonable heat exchanger volume. This causes a number of problems for the fabrication, engine configuration, flow distribution, etc. These problems are discussed in conjunction with experience gained during the development of a number of heat exchangers (1).
Field Experience With the Pace Control System
Authors: Kiscaden R. W. , Hobbs M. M. , Wescott K. R.
Published: April 2015

The Westinghouse PACE 260 combined cycle control system was first shipped to the field January 1973. It was shipped to the Comanche Site of Public Service of Oklahoma, at Lawton, Okalhoma, Fig. 1, to control the Westinghouse prototype combined cycle plant. Since then, nine other PACE 260 control systems have been shipped to other combined cycle plant sites. The PACE control system was a new system controlling a new process, the combined cycle. Problems were experienced and problems were solved. At this date, all the control system functions, both analog and digital, have been field tested and are functioning. This paper discusses the experiences at the installed PACE 260 combined cycle plants which were on line producing megawatts at the time this paper was written. The sites are: Dos Bocas and Gomex Palacio in Mexico for the Mexico Commission Federal de Electricidad; El Paso, Texas for El Paso Electric; and Comanche for Public Service of Oklahoma. Changes were made to the process, to primary sensors, final control elements and to the control system. This paper discusses some of these changes, the reason for them, and the effects of implementing them.
Effects of C and Hf Concentration on the Mechanical Properties of Wrought Superalloys Based on NASA IIB-11 Produced From Prealloyed Powders
Authors: Miner R. V.
Published: April 2015

This work describes the effects of C and Hf concentration on the mechanical properties of NASA IIB-11, a candidate material for advanced-temperature gas turbine engine disks. IIB-11 and four alloys of varied C and Hf concentrations were produced as cross-rolled disks from hot-isostatically pressed powder billets. The lower C, higher Hf modification exhibited the best mechanical properties at 760 C and below. These properties were at least equivalent to those of other candidate alloys for advanced temperature disks. Because of their finer grain sizes, all of these powder metallurgy alloys had lower rupture strength, however, than that achieved previously in conventionally processes IIB-11.
Evaluation of Improved Cycles for Marine Application of an Aircraft Derivative Gas Turbine
Authors: Tanabe K. , Okugawa R.
Published: April 2015

In spite of its good efficiency, the operational fuel cost of aircraft derivative second generation gas turbines is a large owing to the required use of distillate oil. In our attempt to improve the situation, some improved cycles are considered. Technical discussion is given to unfashionable cycles, supercharged and cooled intake air cycles. An economical evaluation is made of these cycles and a combined steam cycle, taking a simple cycle as a basis for calculation.
Modern Gas Turbines for Low Btu Gas Fuel Operation
Authors: Palmer R. J. , Burgess M. R.
Published: April 2015

A brief review of BBC gas turbine experience in operation on low Btu gas is presented. The applicability of this experience to combustion technology associated with current generation Turbodyne/BBC turbines is discussed. The integration of a currently available turbine design into possible synthetic fuel systems is presented as an available alternative in generation system planning.
The Potential of Oxide Dispersion Strengthened Superalloys for Advanced Gas Turbines
Authors: Oenjin J. S.
Published: April 2015

Both the performance and life of gas turbines are frequently controlled oy properties of materials in critical components. The different properties required simultaneously for a given part have placed extreme demands on conventional wrought or cast nickel-base superalloys. The recently developed mechanical alloying process has allowed achievement of a new combination of important properties, such as: oxidation resistance, sulfidation resistance, and elevated temperature rupture strength. The interaction between the unique stress/temperature/time behavior of an oxide dispersion strengthened superalloy and blade configuration is treated. Significant potential for improvements in gas turbine performance is found based on a simplified energy exchange model.
Study of Light Weight Turbine Transmission Systems
Authors: Fessett D. J.
Published: April 2015

Several transmission systems that are applicable to advanced marine vessels were investigated to determine if drives other than right-angle gearboxes would be practical in transmitting 50,000 (37.3 NW) hp from dual gas turbines downward through a vertical distance of 20 (6.10 m) ft to a propeller drive shaft. These systems included: hydraulic power, chain drive, steel tape drive, and a slider crank drive. Results of this survey indicated the right-angle bevel gear drive was the optimum system considering our present state-of-the-art. Further investigation was performed to optimize turbine and gearbox arrangement using weight, reliability, efficiency, serviceability, technical risks, and relative cost as the determining factors.
Programs to Evaluate Gas Turbine Maintenance and Operating Techniques
Authors: La Stella J.
Published: April 2015

During the early 1970’s, many utilities installed large numbers of gas turbines. At that time, the gas turbine industry was still in comparative infancy, with very little utility operating experience. Consequently, initial operating problems were both unpredictable and monumental. Consolidated Edison Co. installed 44 aircraft derivative and 61 heavy industrial gas turbines totaling 2800 MW of capacity during this period. It is not surprising then, that our Company has experienced almost every type of operating and maintenance problem associated with the use of gas turbines to produce electric generation. Also, since gas turbines are such a significant part of our total generating capacity (approximately 25 percent), we have had a special interest in exploring the capability of these machines to improve the overall operation of our system, beyond present utility practice. The purpose of this paper is to: (a) present our observations and conclusions regarding what we consider to be the industry’s most significant maintenance problem — turbine sulfidation, (b) outline the progress made in the repair techniques of sulfidated blades, and (c) illustrate two unique applications of gas turbines to improve system operation — load frequency control and synchronous reactor operation.
XFV-12A Propulsion System Development
Authors: Delany J. T. , Jenkins G. M.
Published: April 2015

The XFV-12A total powered lift/thrust system being developed under contract for the U. S. Navy is described. The description includes design and development to date of the inlets, engine integration, the diverter valve with plug nozzle, the lift system augmenter supply ducting, and lift/thrust augmenter hardware. The development process description includes system design philosophy and criteria, analysis, test facilities utilized, model and full-scale testing and evaluation.
Gas Turbine Operation in Extreme Cold Climates
Authors: Patton R. E.
Published: April 2015

The effects of extreme cold weather on gas turbine operation are described. Suggestions are made which will enhance overall operational effectiveness. The comments and specific recommendations are based on Solar’s experience in the supply and maintenance of over a thousand Saturn and Centaur gas turbines in worldwide cold weather locations. Each manufacturer’s gas turbine has its own tolerances and design constraints; each installation site its own peculiar climatic conditions; and each user his own operational requirements. A clear understanding by all parties involved of the requirements, conditions, and constraints will result in a dependable and economical installation.
Models for the Representation of Turbomachine Blades During Temperature Transients
Authors: Maccallum N. R. L.
Published: April 2015

When the operating conditions of turbomachinery are changed, as when a gas turbine is accelerated, heat is transferred from or to the various components of the machine. One of the significant heat transfers is with the blading. Several simple models for the blade and platform arrangement are compared. Satisfactory representation is obtained from a simple eight-element Finite Difference Model and from a Revised Fin Model. Computer running times are similar, but the latter allows more convenient hand calculations and is more suitable when predicting the thermal response of casings or disks to which the blades are attached.
Assembly and Test of a Direct Reversing Marine Gas Turbine
Authors: Rucigay J. C.
Published: April 2015

A marine gas turbine, capable of obtaining rapid propeller thrust reversals for such maneuvers as docking or crash reversal operation, without the aid of controllable pitch propellers or motor-generator units, was successfully test demonstrated using full-scale hardware. This paper describes the design pictorially during the assembly stages in addition to full load performance and control transient data. The data demonstrates that the turbine can be controlled in either direction within an infinite range of speeds from full ahead to full astern. Test results are compared with previous analytical predictions verifying the full power capability of this turbine design for marine applications or other industrial uses.
Model Tests for the Detailed Investigation of the Trailing Edge Flow in Convergent Transonic Turbine Cascades
Authors: Sieverding C. , Decuyper M. , Colpin J. , Amana O.
Published: April 2015

The paper presents some experiments concerning the trailing edge flow of transonic turbine bladings. The experiments are conducted on a model simulating very closely the flow in the overhang section of convergent turbine cascades. The first test series simulates cascade flow conditions with shock free flow in the overhang section (limit load conditions), while the second test series simulates cascade flow conditions characterized by trailing edge shock interferences with the flow in the overhang section. Particular attention is given to the trailing edge separation shock and the length of the isobaric trailing edge base region. The test results indicate that the strength of the separation shock for the rounded trailing edge is of the same order as the strength of the lip shock found by Merzkirch for sharp-edged wedges. The length of the isobaric base region is only 60 to 80 percent of the trailing edge thickness, while the pressure recovery region is about twice as long as the constant pressure region. From an analysis of the flow parameters influencing the base pressure, it is concluded that the boundary-layer shape factor plays a significant role in establishing the base pressure.
Development and Design of Directionally Solidified Eutectic Airfoils for Advanced Gas Turbine Engines
Authors: Gell M. , Thomas K. M.
Published: April 2015

Directionally solidified eutectic airfoils for advanced gas turbine engine applications are undergoing intensive development in a number of laboratories in the United States and Europe. These materials offer the potential of a 40 percent or greater increase in creep strength for high work engines or a 50 K or more increase in blade metal temperature for growth versions of current engines. The development status of these alloys will be described with emphasis on casting techniques, mechanical properties, and coatings for the gamma/gamma prime + delta (γ / γ′ + δ) D.S. eutectic. The implications of the elastic anisotropy and low off-axis properties of the D.S. eutectics to turbine blade design and analysis will be discussed.
Turbine Environmental Behavior in LM2500 Applications
Authors: Wortman D. J. , Fryxell R. E. , Bessen I. I.
Published: April 2015

A comparison is made among turbine vanes operated on a gas line pumper with natural gas fuel, and on two ship propulsion engines using liquid fuels. The metallographic assessment of turbine parts and a knowledge of service operating conditions offer clues to survivability in aggressive and benign environments.
Cycle Analysis of Air-Storage Power Plants
Authors: Li K. W. , Duckwitz N. R.
Published: April 2015

Underground air storage and gas turbines are combined to form an air-storage power plant for peak power generation. This generating system will lower the peak power generation cost at the time when the fuel price is high. The paper is intended to present thermodynamic analysis of various cycle arrangements. The air storage is of constant pressure type. In the paper, the parameters affecting the system performance characteristics are identified and studied. Also included are the effects of intercoolers and recuperators. The storage volume is predicted in terms of unit peaking power production.
The Use of Experimental Interstate Data for Matching the Performance of Axial Compressor Stages Having Variable-Setting-Angle Blade Rows
Authors: Brown L. E.
Published: April 2015

Stage performance characteristics provide a powerful analytic tool for experimentally matching the stages and blade rows of an axial-flow compressor, while the variable stage compressor component test rig provides a most powerful experimental tool for developing compressors. This paper describes: Why and how the stage characteristics “normalized” to correct them for changes of stator setting angles, how these normalized characteristics can be fully defined for every stage; and how these characteristic can point the way to a well-matched configuration of setting angles. In addition, it proposes methods for distinguishing between the stall of rotors and stators and for normalizing the characteristics of stages with variable-setting rotor blade rows.
Salt in Sea Atmosphere and its Removal for Gas Turbines
Authors: Yoshimoto K. , Hirata Y. , Chiba M.
Published: April 2015

Concentration and size distribution of sea salt particles in air were investigated aboard four different ships (a 10,000-GT class cargo carrier, a 200,000-DWT class oil tanker, and two destroyer-escorts) under various conditions of weather and maneuvering of ships. The data for the concentration and size distribution were converted into basic design data in the light of theories of geophysics. In the meanwhile, the performance characteristics of the demister elements (the fibrous filter and the vane separator), e.g., the pressure loss and collection efficiencies for the particle size in mist, were determined by bench tests. Based on those findings, a demister system applicable to actual ships was proposed, and its performance was predicted for various weather conditions.
A Simple Method for Supersonic Compressor Cascading Performance Prediction
Authors: Gustafson B.-A.
Published: April 2015

This investigation is an effort to break down the very complicated flow of a supersonic compressor cascade into a simple model which, in spite of the simplifications, is able to predict realistic values of overall cascade performance parameters. The investigation is limited to high reaction cascades and is focused on design conditions for Double-Circular-Arc blading. The selected flow model includes the inlet flow, which determines the incidence angle and the massflow, the λ-shaped passage shock followed by a boundary-layer separation, the formation of a jet and wake flow, the second shock, and finally the mixing process to a uniform flow downstream of the cascade. Calculated results (inlet Mach number range 1.1 to 1.5) are compared to measured data taken from the literature.
Gas Turbines Burning Dirty Fuels
Authors: Bammert K. , Sandstede H.
Published: April 2015

Because of the increasing need for electricity and of the rising prices for oil and natural gas, turbines using other fuels are again becoming of interest. Waste gases, such as blast-furnace gases, or pulverized coal are under discussion as fuels. These fuels mostly contain very high proportions of dust and dirt. Blast-furnace gas turbines have been i operation in German foundries since the end of the fifties. A considerable amount of experience has been gained from these open-cycle gas turbines. The effects of pollution, erosion, and corrosion with reference to profile shape and surfaces are to be illustrated here. Investigations using roughened blade profiles were carried out on a test turbine and a test compressor, based on the results gained under operating conditions. The effects of profile changes on the output and the efficiency of the whole gas turbine plant were worked out. By using the results and experience gained, deductions are made for the construction and operation of open-cycle gas turbines burning dirty fuels.
Prediction of Diffuser Core Flow Fluctuations due to Oscillating Turbulent Flow
Authors: Schachenmann A. A. , Rockwell D. O.
Published: April 2015

Theoretical consideration of the time-dependent diffuser core flow, involving two limiting models (high frequency and low frequency) for the time-dependent effective core flow area results in predictions for decay of the first harmonic core velocity and wall pressure amplitudes with streamwise distance. In order to predict these decays, it is only necessary to specify time mean core flow, and either time-dependent diffuser inlet or exit conditions. The theoretical models are compared with experiments for diffuser inlet conditions spanning a decade of dimensionless frequencies. The high-frequency model best predicts the decay of core velocity fluctuations and wall pressure fluctuations in the streamwise direction. A backward calculation scheme, which uses diffuser exit conditions as initial conditions, enables good prediction of the fluctuating wall pressure when the diffuser exit exhausts into the atmosphere. An order of magnitude analysis yields a simple expression for decay of the core velocity fluctuations when the dimensionless frequency is approximately unity.
CFM56 Turbofan Engines: General Electric/SNECMA Cooperative Engineering Development Program
Authors: Caffier E. , Kohn A. O.
Published: April 2015

General Electric Company, USA, and the Societe Nationale d’Etude et de Construction de Moteurs d’Aviation (SNECMA), France, have formed a joint company to develop a “ten ton” high bypass turbofan engine for the commercial and military markets that are expected to exist in the late 1970’s and the 1980’s. Overall program management, marketing, engineering, production, and product support are elements that have been defined to make this program workable. This paper deals with the management of the engineering aspects of the development program and describes the division of responsibilities, interface definition and control, integration and communications, requirements and security aspects of the program. The program was started in 1971 and preliminary design activities were conducted for several years. Hardware design and development started in 1973 and now four engines are on test, two in the United States and two in France. Experience to date indicates that barriers of distance and language are being overcome and that this type of program can be successful.
Fighting Sulfidation With a Chromium Bearing Fuel Additive
Authors: Mitchell A. H. , Bornstein N. S.
Published: April 2015

Sulfidation attack, the accelerated rate of oxidation of gas turbine vanes (stators) and blades (buckets) is a form of hot corrosion, which can occur whenever alkali salts are present in the inlet air and/or as an impurity in the fuel. The corrosive alkali salt found on affected hardware is primarily sodium sulfate, which is composed of sodium ions, sulfate ions and oxide ions. The oxide ions react with and disrupt the normally protective oxide scale which results in accelerated rates of oxidation. Chromium oxide reacts with oxide ions. By reducing the oxide ion concentration of the fused salt, the sulfidation process is prevented before it starts. The ability of a chromium additive in the fuel to suppress sulfidation attack has been demonstrated in laboratory and burner rig tests and more recently in the field. Field experience consists of over 6000 hr of gas turbine operation. It is the purpose of this paper to describe the sulfidation inhibiting process and report the laboratory, burner rig, and field tests.
A New System for Preventing Icing of Gas Turbine Inlets
Authors: Gillingham G. R.
Published: April 2015

A new system for preventing condensate and precipitate icing of gas turbine inlet systems has been developed. This system uses a combination heat exchanger/moisture separator called an Anti-Ice Moisture Separator (AIMS) to provide icing protection without the need to heat the inlet air to 0 C or above. Turbine exhaust gas heats the AIMS surfaces and thereby prevents ice from forming on them. Turbine inlet air passing over these surfaces is heated by convection. No mixing of exhaust gas with inlet air occurs. Condensate icing is prevented by heating the air enough to prevent it from falling below the dew point temperature anywhere in the inlet system. Precipitate icing is prevented by separating most water droplets from the inlet air and evaporating the rest before they impact and freeze on cold surfaces. The AIMS system has successfully prevented turbine inlet icing in temperatures as low as −22 C (-8 F) during field tests. It is anticipated that AIMS systems will be able to prevent inlet icing at any ambient temperature that may be encountered.
Reversed Flow Phenomena Within Centrifugal Compressor Channels at Lower Flow Rate
Authors: Mizuki S. , Hattori T. , Ariga I. , Watanabe I.
Published: April 2015

It is recognized today that centrifugal compressors exhibit their inherent characteristics at lower flow rate and this is due to the reversed flow phenomena taking place within compressor channels. In the present study, the authors precisely observed these reversed flow phenomena within compressor channels in an experiment. Many sorts of measuring techniques were employed to clarify the nature of them. By these investigations, it became clear that these phenomena primarily depended on the shocked inlet condition at inducer inlet, where shocked inlet condition designated that the direction of the relative velocity at the inducer inlet deviated from the inducer mean camber line there. Especially, the balance of the body forces and the pressure gradients between the separated wake flow and the main flow was a predominant factor. Reversed flow phenomena observed within compressor channels appeared within the inlet duct near the shroud casing, within the inducer and impeller channel as a three-dimensionally skewed eddy, at the walls of the diffuser, and along the shroud casing.
Microprocessor Based Controls for Gas Turbines
Authors: Powell R. D. , Burrage R. G.
Published: April 2015

The fundamental advantage of the reprogrammable general-purpose digital computers is their ability to perform accurately and repeatably calculations of any complexity. In practical terms, the computing task determines the size of program memory required and the run time of the calculations. The former affects cost; the latter affects the real-time performance for control applications. This paper discusses how and to what extent these advantages can be implemented assuming that the “digital computer” is a microprocessor plus semiconductor memory and that the applications are naval and industrial gas turbines. Examples are drawn from engine tests that have used a medium-speed microprocessor.
Fluid Film Bearing Housing Design for a Hot Ambient Environment
Authors: McHugh J. D. , Winer W. O. , Robson G. D.
Published: April 2015

Industrial gas turbine rotors sometimes require a journal bearing in a region of the machine surrounded by compressor discharge air. Ambient temperatures in this region may exceed 600 F (588 K), which poses a challenge to bearing designers. The present paper describes housing design approaches to meeting this challenge, an experimental program to evaluate them, and the application of results to operating field units. The experimental program was carried out in a special test facility on full-size housings for a 14-in. journal bearing in a hot, pressurized environment.
Control of a Gas Turbine HTGR
Authors: Openshaw F. , Estrine E. , Croft M.
Published: April 2015

This paper presents a description of the control and protective preliminary system designs for the gas turbine high-temperature gas-cooled reactor power plant (GT-HTGR). The purpose of these systems is the control and safe operation of the plant in accordance with utility practice for large nuclear generation stations, and in the event of an abnormal or accident condition to shut the plant down in an orderly manner and maintain it in a safe shutdown condition. The control system is designed to regulate reactor power, control electric load and turbine speed, control the temperature of the helium delivered to the turbines, and control thermal transients experienced by reactor internal components. In addition, it provides the required control and programming for start-up, shutdown, load ramp, and other expected operations. The control system also handles conditions imposed on the system during upset and emergency conditions, such as loop trip, reactor trip, or electrical load rejection. Under these conditions, reactor power and helium flow are reduced in order to minimize temperature transients imposed on reactor components. The transient analysis and control system selection process which has been used to establish the reference GT-HTGR control system is illustrated in this paper. The study demonstrates not only the design of adequate control, but also reduced severity of plant component design requirements imposed by transient events.
The Effect of Variable Geometry on the Operating Range and Surge Margin of a Centrifugal Compressor
Authors: Whitfield A. , Wallace F. J. , Atkey R. C.
Published: April 2015

Two variable geometry techniques have been applied to a small turbocharger compressor, with the objective of trying to move the peak pressure ratio operating point to lower flow rates, thereby yielding a broad flow range map. Variable prewhirl guide vanes and variable vaneless diffuser passage height have been studied separately. The results obtained with both techniques are compared and the relative merits and demerits with respect to improved flow range and isentropic efficiency penalties are considered.
A method for volumetric imaging in radiotherapy using single x‐ray projection
Authors: Xu Yuan , Yan Hao , Ouyang Luo , Wang Jing , Zhou Linghong , Cervino Laura , Jiang Steve B. , Jia Xun
Published: April 2015

Purpose:

It is an intriguing problem to generate an instantaneous volumetric image based on the corresponding x‐ray projection. The purpose of this study is to develop a new method to achieve this goal via a sparse learning approach.

Methods:

To extract motion information hidden in projection images, the authors partitioned a projection image into small rectangular patches. The authors utilized a sparse learning method to automatically select patches that have a high correlation with principal component analysis (PCA) coefficients of a lung motion model. A model that maps the patch intensity to the PCA coefficients was built along with the patch selection process. Based on this model, a measured projection can be used to predict the PCA coefficients, which are then further used to generate a motion vector field and hence a volumetric image. The authors have also proposed an intensity baseline correction method based on the partitioned projection, in which the first and the second moments of pixel intensities at a patch in a simulated projection image are matched with those in a measured one via a linear transformation. The proposed method has been validated in both simulated data and real phantom data.

Results:

The algorithm is able to identify patches that contain relevant motion information such as the diaphragm region. It is found that an intensity baseline correction step is important to remove the systematic error in the motion prediction. For the simulation case, the sparse learning model reduced the prediction error for the first PCA coefficient to 5%, compared to the 10% error when sparse learning was not used, and the 95th percentile error for the predicted motion vector was reduced from 2.40 to 0.92 mm. In the phantom case with a regular tumor motion, the predicted tumor trajectory was successfully reconstructed with a 0.82 mm error for tumor center localization compared to a 1.66 mm error without using the sparse learning method. When the tumor motion was driven by a real patient breathing signal with irregular periods and amplitudes, the average tumor center error was 0.6 mm. The algorithm robustness with respect to sparsity level, patch size, and presence or absence of diaphragm, as well as computation time, has also been studied.

Conclusions:

The authors have developed a new method that automatically identifies motion information from an x‐ray projection, based on which a volumetric image is generated.