bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser Additive Manufacturing of Novel Aluminum Based Nanocomposite Parts: Tailored Forming of Multiple Materials
Authors: Gu Dongdong , Wang Hongqiao , Dai Donghua
Published: April 2015

The present study has proved the feasibility to produce the bulk-form TiC/AlSi10Mg nanocomposite parts with the novel reinforcing morphology and enhanced mechanical properties by selective laser melting (SLM) additive manufacturing (AM) process. The influence of linear laser energy density (η) on the microstructural evolution and mechanical performance (e.g., densification level, microhardness, wear and tribological properties) of the SLM-processed TiC/AlSi10Mg nanocomposite parts was comprehensively studied, in order to establish an in-depth relationship between SLM process, microstructures, and mechanical performance. It showed that the TiC reinforcement in the SLM-processed TiC/AlSi10Mg nanocomposites experienced an interesting microstructural evolution with the increase of the applied η. At an elevated η above 600 J/m, a novel regularly distributed ring structure of nanoscale TiC reinforcement was tailored in the matrix due to the unique metallurgical behavior of the molten pool induced by the operation of Marangoni flow. The near fully dense TiC/AlSi10Mg nanocomposite parts (>98.5% theoretical density (TD)) with the formation of ring-structured reinforcement demonstrated outstanding mechanical properties. The dimensional accuracy of SLM-processed parts well met the demand of industrial application with the shrinkage rates of 1.24%, 1.50%, and 1.72% in X, Y, and Z directions, respectively, with the increase of η to 800 J/m. A maximum microhardness of 184.7 HV0.1 was obtained for SLM-processed TiC/AlSi10Mg nanocomposites, showing more than 20% enhancement as compared with SLM-processed unreinforced AlSi10Mg part. The high densification response combined with novel reinforcement of SLM-processed TiC/AlSi10Mg nanocomposite parts also led to the considerably low coefficient of friction (COF) of 0.28 and wear rate of 2.73 × 10−5 mm3 · N−1 · m−1. The present work accordingly provides a fundamental understanding of the tailored forming of lightweight multiple nanocomposite materials system by laser AM.
The Evaluation of Fuel Property Effects on Air Force Gas Turbine Engines Program Genesis
Authors: Jackson T. A.
Published: April 2015

The Air Force has conducted a series of investigations to quantify the effects of certain fuel properties on the operability and durability of its aircraft gas turbine engines. Initially these efforts were conducted on a small number of engines intended to be representative of the majority of gas turbine engines in the Air Force inventory. The testing was conducted exclusively in rigs representing the combustor and fuel nozzle components of these engines of interest. Test fuels for these programs were primarily blends of hydrocarbons. These test fuels exhibited significant variations in several major fuel properties. Based on results of these evaluations a second generation of test activity in fuel effects area was formulated. Engine system selection was broadened to include more considerations. Test fuels were reduced in number and priorities for modification of certain fuel properties were adjusted. This paper presents dominant test results of early fuel effects programs and supplemental background which dictated the structure of the second, more comprehensive program.
Flow Transition Phenomena and Heat Transfer Over the Pressure Surfaces of Gas Turbine Blades
Authors: Brown A. , Martin B. W.
Published: April 2015

Detailed examination of flow measurements over concave pressure surfaces suggests that interaction of Taylor-Goertler vorticity with mainstream turbulent exerts only limited influence in enhancing laminar boundary-layer heat transfer. While transition is primarily controlled by the Launder laminarisation criterion, the Goertler number at which it subsequently occurs is not solely determined by turbulence intensity. Adoption of K >2.5.10 ± as a design criterion for the pressure surfaces of turbine blades would appear to have significant advantages in terms of reduced heat transfer, increased lift, and lower aerodynamic drag.
Design and Preliminary Results of a Fuel Flexible Industrial Gas Turbine Combustor
Authors: Novick A. S. , Troth D. L. , Yacobucci H. G.
Published: April 2015

The work described in this paper is a part of the DOE/ LeRc “Advanced Conversion Technology Project” (ACT). The program is a multiple contract effort with funding provided by the Department of Energy and Technical Program Management provided by NASA LeRc. It is anticipated that future industrial gas turbine engines will require fuel flexibility. The emphasis in this paper is the fuel flexible combustor technology developed under the “Low NOx Heavy Fuel Combustor Concept Program” for application to the Detroit Diesel Allison (DDA) Model 570-K industrial gas turbine engine. The technology, to achieve emission goals, emphasizes dry NO, reduction methods. Due to the high levels of fuel bound nitrogen (FBN) control of NOx can be effected through a staged combustor with a rich initial combustion zone. A RICH/QUENCH/LEAN (RQL) variable geometry combustor is the technology that will be presented to achieve low NO, from alternate fuels containing FBN. The results will focus on emissions and durability for fuel flexible operation.
Transient Analysis of Rotor-Bearing Systems Using Component Mode Synthesis
Authors: Nelson H. D. , Meacham W. L.
Published: April 2015

A method of component mode synthesis is utilized to determine the forced response of linear multi-shaft rotor-bearing systems. The formulation allows for simulation of system response due to blade loss, base shock, maneuver loads, and specified fixed frame forces. The motion of each rotating component of the system is described by superposing constraint modes associated with boundary coordinates and constrained precessional modes associated with internal coordinates. The precessional modes are truncated for each component and the reduced component equations are assembled to obtain a set of complex system equations of reduced order. The method allows for nonsymmetric effects and comparative results are presented for various levels of mode truncation for two example cases.
Regenerative Gas Turbines for Naval Escort Ships
Authors: McCoy A. W.
Published: April 2015

An analysis of naval ships for escort mission applications has included gas turbines of regenerative cycle variations to assess their potential benefits in terms of fuel economy. Significant reduction of mission fuel requirements can be realized by the use of regenerative gas turbines in place of simple cycle engines. With the addition of variable geometry and compression cooling features, the use of regenerative cycle engines offers potential fuel savings of over 40 percent as compared to simple cycle gas turbines for escorts of 2000 tons and composite mission ranges of 5000 nm. Further exploitation of the improved regenerative cycle efficiency in combination with smaller ship sizes can result in even greater reduction of fuel requirements.
Development of the Self-Temperature Compensated Resistance Strain Gage Used up to 700 C
Authors: Zhi-qi Z. , Pei-qing H.
Published: April 2015

This paper represents a self-temperature compensated resistance strain gage which is of combined type and developed recently. Because the scatter of the thermal output and the drift of the strain gage are smaller in all heat cycles, they could be compensated by bridge circuit or by dummy gage and better accuracy can be obtained. The gage enables engineers to measure the hot-end parts of aeroengines.
Optimization of the HHT 1640MWth Demonstration Nuclear Power Plant (HHT-Project)
Authors: Gregory N. , Zollinger E.
Published: April 2015

In connection with the HHT-Project, the Swiss Federal Institute for Reactor Research has performed an Optimization Analysis of the HHT-1640 MWth Demonstration Plant with a Closed Cycle Helium Turbine One Loop Concept with Intercooling. This paper gives a description of the analysed plant and the development of the optimization techniques utilized, followed by the presentation of results of both optimization and sensitivity analysis calculations.
Aerodynamic Design and Testing of an Improved 1st Stage Compressor Rotor for a Heavy Duty Gas Turbine
Authors: Ispas I. , Zollinger H. J.
Published: April 2015

To evaluate the potential of the compressor of Sulzer’s Typ 3 gas turbine, a series of engine tests was analyzed with two computer codes. The comparison between measured and calculated performance map are given in the paper. The design goal was to find modifications, which can be applied easily to already operating engines. The simplest option-increase of shaft speed with the existing blades-would have caused high loss due to increased tip Mach number. The calculation revealed, that a newly designed first rotor blade is an appropriate modification to increase massflow and efficiency. No further change is required, because the calculations indicate, that all subsequent stages operate at near optimum incidence. The calculations were confirmed experimentally. The paper presents the new rotor blade and its influence on the compressor calculated and measured performance.
A Versatile Microprocessor Controller for Low Cost Helicopter Applications
Authors: Justice N. A.
Published: April 2015

The benefits of the microprocessor in the Gas Turbine Control field have been demonstrated in their improved performance and versatility for the increasingly complex control requirements. The ability to design systems that are compatible with the environment requires extra attention, particularly for a low cost solution. The key design decisions and overall philosophy to meet these criteria are presented along with the practical results.
Full-Authority Digital Electronic Controls for Civil Aircraft Engines
Authors: Kendell R.
Published: April 2015

In the U.K. full-authority digital controls are now being successfully demonstrated on military aero-engines following some years of practical research into suitable configurations for this class of power plant. For the case of Civil aero-engines the appropriate configuration of systems that will enter service from the mid-1980’s has been the subject of much debate between engine/airframe manufacturers and the principal accessory suppliers. This paper discusses the major features that will be embodied in these new systems, particular reference being made to: System tasks and performance requirements; configuration; life cycle costing; electronics design and system interfacing; and reliability and integrity.
ITI GT601: A New Approach to Vehicular Gas Turbine Power Unit Design
Authors: Woodhouse G. D.
Published: April 2015

The Industrial Turbines International GT601 Engine has been designed and is currently being tested as a gas turbine power plant specifically intended for on-highway truck propulsion. The somewhat unique aeromechanical design reflects the uncompromising economic demands of this market in terms of reliability, performance, and cost. This paper describes some of the studies leading to the adoption of the medium-pressure recuperated cycle. The near-term goals of performance superiority relative to current diesels can be achieved with the all-metal version of this engine. The introduction of ceramic components into future high-temperature versions of the GT601 indicates supremacy over projected turbo-compound, adiabatic, bottoming cycle, and similar diesel engine developments projected for the late 1980s.
Deposition: Hot Corrosion in Gas Turbine Engines
Authors: Bornstein N. S. , DeCrescente M. A.
Published: April 2015

The superalloys employed in industrial marine and aircraft gas turbine engines are among the strongest and most oxidation resistant structural materials known. Moreover, it is common practice to further increase the surface stability of hot turbine components by the use of protective coatings. Nevertheless accelerated oxidation and corrosion occurs and can limit the use life of gas turbine components. The principal constituents of the deposits that accumulate on turbine components that are associated with accelerated corrosion are alkali salts. The source of the alkali constituents are generally believed to be sea salt crystals, which can travel hundreds of miles with the prevailing winds, or salt water contamination of otherwise clean fuels. The objective of the studies reported herein is to relate the modes of deposition of salts with corrosion and investigate the role of char as it affects corrosion so that the appropriate steps can be taken to increase gas turbine life.
Optimum Friction Damping of a Flexible Rotor
Authors: Hibner D. H. , Bhat S. T. , Buono D. F.
Published: April 2015

The dynamic response of a multi-mass, large scale, flexible rotor mounted on anti-friction bearings and a variable force friction damper is investigated both analytically and experimentally. The rotor is a scale model of a gas turbine engine shaft with two critical speeds within its speed range of 0 to 8000 rpm. The experimental results define the under- and over-damped regimes of dynamic rotor response and clearly indicate optimized damping. Analytically both a complete geometric model and a simplified single mass-spring-damper model are formulated. Critical speeds, and imbalance response are calculated for various friction damper parameters. The presence of optimized damping is predicted. The correlation of analytical and experimental results are discussed.
Evaluation of Concepts for Controlling Exhaust Emissions From Minimally Processed Petroleum and Synthetic Fuels
Authors: Russell P. L. , Beal G. W. , Sederquist R. A. , Schultz D.
Published: April 2015

The work described in this paper is a part of the Department of Energy/Lewis Research Center Advanced Conversion Technology (ACT) Project. The program is a multiple contract effort with funding provided by the DOE and technical management provided by the NASA-Lewis Research Center. Continued development of combustion technology is needed to provide utility and industrial gas turbine engines capable of sustained, environmentally acceptable operation when using minimally processed and synthetic fuels. This paper describes an exploratory development effort to identify, evaluate and demonstrate techniques for controlling emissions of Nox and smoke from combustors of stationary gas turbine engines. Preliminary results indicate rich primary zone staged combustion provides environmentally acceptable operation with residual and/or synthetic coal derived liquid fuels.
Closed-Cycle Gas Turbine Applications for Fusion Reactors
Authors: McDonald C. F. , Wong C. P. C.
Published: April 2015

There is increasing worldwide interest in fusion reactors as an energy source for electrical power generation. For such plants, which are projected for operation in the early decades of the 21st century, the choice of thermodynamic cycle for conversion of fusion reactor heat into electricity plays an important role in studies currently in the embryonic stage to evaluate performance, economics, safety, and operational features. A brief outline is given of some of the fusion reactor types currently under investigation. In this paper emphasis is placed on the utilization of a closed-cycle helium gas turbine power conversion system since its operational flexibility with regard to power and heat production and adaptability to economic dry cooling seem well suited to projected user energy needs of the future. The promise of an efficiency of over 50 percent (when operated in a binary cycle mode) makes the closed-cycle gas turbine an attractive power conversion system candidate as the goal of power production through a sustained fusion reaction in a confined plasma is realized. It is projected that the coupling of a closed-cycle gas turbine to a fusion reactor represents a challenging task for gas turbine engineers in the 21st century, and may be regarded as the ultimate application of the gas turbine prime-mover.
Ammonia Bottoming Cycle Development at Electricité de France for Nuclear Power Plants
Authors: Fleury J.
Published: April 2015

An ammonia bottoming cycle is under active development at Electricité de France. To be implemented in a nuclear power plant downstream from the steam cycle, shortened for this application, its purpose is to make it possible to practice air cooling in satisfactory economic conditions. After an analysis of the main parameters of the bottoming cycle (H2O/NH3) (i.e., back pressure and temperature differences in the heat exchangers) its advantages are enumerated: in addition to those the dry cooling concept, the major benefit consists of the fact that the bottoming cycle makes use of low atmospheric temperatures in winter, producing a significant increase in the power output, just when it is most needed in many geographic locations. Emphasis is placed on the experimental work performed on E.D.F. test facilities and the construction of a 20-MWe demonstration bottoming cycle power plant at Gennevilliers power station. A brief account is given of test results and experimental programs.
Experience With Large Heavy-Duty Gas Turbine Rotors
Authors: Schmoch O. R. , Deblon B.
Published: April 2015

The peripheral speeds of the rotors of large heavy-duty gas turbines have reached levels which place extremely high demands on material strength properties. The particular requirements of gas turbine rotors, as a result of the cycle, operating conditions and the ensuing overall concepts, have led different gas turbine manufacturers to produce special structural designs to resolve these problems. In this connection, a report is given here on a gas turbine rotor consisting of separate discs which are held together by a center bolt and mutually centered by radial serrations in a manner permitting expansion and contraction in response to temperature changges. In particular, the experience gained in the manufacture, operation and servicing are discussed.
Shell U.K. Exploration and Productions Experience With Large Gas Injection Compressors on the Northern North Sea Platforms
Authors: Suyderhouds J.
Published: April 2015

This report highlights many difficulties, covering a period of two years, of gas compressor commissioning in the Brent Field. It is intended to give an insight of the problems encountered, with the objective to, wherever possible, avoid repetition. It is in most cases the DESIGN STAGE, where the lessons learned should be implemented, because it is very often too difficult and sometimes impossible to make improvements in compressor modules of offshore platforms.
Gas Turbine Vanadium Inhibition
Authors: Krulls G. E.
Published: April 2015

The mechanism of gas turbine vanadium inhibition is discussed as well as corrosion, hot gas path deposition and exhaust gas emissions. A cost comparison is presented for the various types of inhibition based on a typical power plant situation. A brief description is provided of three different kinds of inhibition systems. The aim of this paper is to provide the gas turbine user with a practical evaluation of the various inhibition processes.
IM 2000 Marine Gas Turbine: Design, Development and Testing
Authors: Tanabe K. , Aoki C.
Published: April 2015

An 18,000-hp class marine gas turbine has been developed. Major design target to attain a highest possible part load efficiency has been realized. Through testings high reliability and good maintainability have been confirmed. Some application study has also been conducted.
A Corrosion-Erosion Test Rig for High Temperature Turbine Materials Evaluation
Authors: Mogul J. , Wolosin S. , Eckstein A.
Published: April 2015

One key to the production of clean, efficient electricity from the combustion of coal-derived fuels is an advanced design, combined-cycle power conversion system. A major element in this system is a gas turbine which can operate at temperatures over 2600 F (1427 C) on synthetic fuels containing both erosive and corrosive species. A concept which can effectively deal with both the high gas temperature and the aggressive atmosphere is Transpiration-Air-Cooling (TAC). TAC turbine vanes and blades utilize a load carrying strut, and a porous metal airfoil through which a protective barrier of cooling air diffuses. Materials engineers are continually seeking alternate materials for the porous airfoil which offer opportunities for further improving TAC turbine efficiency, without sacrificing durability. This paper describes results obtained from tests performed in a corrosion-erosion rig operated under the DOE sponsored HTTT Program. The rig evaluated a series of TAC airfoil materials in a high temperature turbine synfuel environment.
A Family of Small, Low Cost Turbojet Engines for Short Life Applications
Authors: Barbeau D. E.
Published: April 2015

A family of small, low cost turbojet engines for short life applications is described. The family is based on the J402-CA-400 turbojet engine which was developed during the early 1970’s for the Harpoon Weapon Systems, a tactical, anti-ship cruise missile capable of air, surface or underwater launch. The Harpoon turbojet engine entered production in 1976 and, since then, has spawned a series of derivative applications. These include missile, target, and RPV systems with thrust requirements from 178 to over 535 daN (400 to over 1200 lb). The paper describes the current status of the engine and the relationship of the derivative applications to this baseline configuration.
Cooled Radial In-Flow Turbines for Advanced Gas Turbine Engines
Authors: Lane J. M.
Published: April 2015

While the radial in-flow turbine has consistently demonstrated its capability as a high-performance component for small gas turbine engines, its use has been relegated to lower turbine-inlet-temperature cycles due to insurmountable problems with respect to the manufacturing of radial turbine rotors with internal cooling passages. These cycle temperature limitations are not consistent with modern trends toward higher-performance, fuel-conservative engines. This paper presents the results of several Army-sponsored programs, the first of which addresses the performance potential for the high-temperature radial turbine. The subsequent discussion presents the results of two successful programs dedicated to developing fabrication techniques for internally cooled radial turbines, including mechanical integrity testing. Finally, future near-term capabilities are projected.
Sintering Microstructure and Properties of Si3N4 and SiC Based Structural Ceramics
Authors: Quackenbush C. L. , Neil J. T. , Smith J. T.
Published: April 2015

The observed properties of typical sintered ceramic alloys based on Si3N4 and SiC are discussed. Properties result from interaction between various components of the phase assemblage. The pure single phase components are inherently strong because of their covalent bonding but they are unsinterable without densification aids. These aids change composition and microstructure, thus can strongly influence some properties. The effect of composition and microstructure on properties of sintered Si3N4 and SiC based ceramics is described.
Engine Maintenance Cost Calculation Method
Authors: Curry C. E.
Published: April 2015

The Allison projected engine operating cost technique allows calculation of engine maintenance direct operating costs for various maintenance concepts and flying programs. Cost effects resulting from predicted or measurable effects of environment or mission constraints can also be calculated. This technique may be used to develop sensitivity analysis around nominal cost driver values. The technique discussed was designed for use with a hand-held programmable calculator.
Similarity Law of Transonic Flow Fields Around Cascades
Authors: Zhou S. , Shen M. Y. , Lin B. Z.
Published: April 2015

In order to extend the usage range of a cascade having excellent aerodynamic performance, it is beneficial to investigate the similarity between different flow fields. Von Karman gave transonic similarity law of two-dimensional isolated airfoils many years ago. However, the law of cascades is still different from that of airfoils. This paper points out that, to guarantee similarity between two flow fields around cascades, it is necessary that five corresponding transonic similarity parameters must be kept equal. Also some examples have been presented in this paper for demonstration. They indicate that the similarity law will help us to obtain rapidly many similar transonic flow fields around cascades at different operating conditions from a known flow field around a given cascade.
Studies of Full-Coverage Film Cooling: Part 2 — Measurement of Local Heat Transfer Coefficient
Authors: Kumada M. , Hirata M. , Kasagi N.
Published: April 2015

The local heat transfer coefficient of full-coverage film-cooled wall has been measured by using the law of analogy to mass transfer. For this experiment, the technique of sublimation of naphthalene was used. The geometric shape of FCFC plate and the experimental condition were the same as those in Part 1. From these experiments, the effects of the mass flux ratio and non-dimensional injection wall temperature ratio on the local Stanton number are made clear and it is confirmed experimentally that the local Stanton number is a linear function of non-dimensional temperature ratio as expected from the analysis. Furthermore, the local heat transfer coefficient on the backside surface has been obtained and a technique for the improvement of cooling effectiveness is discussed.
Low Emissions Silo Combustor
Authors: Krockow W. , Fiorentino A. J.
Published: April 2015

Substantial improvements to reduce emissions have been obtained by modifying conventional burner designs. However, to satisfy EPA and applicable local NO, emissions regulations without water or steam injection, an approach which avoids diffusion controlled combustion must be found. This paper describes an analytical design study conducted to integrate a lean, premixing, prevaporizing burner concept into a silo combustor which combines the benefits of the low emissions dry NO, system with those of the off board combustor design philosophy. This low emissions system permits a high degree of vaporization and homogeneity prior to combustion and ease of staging individual fuel injectors to cover the operating range of a single shaft gas turbine.
Effect of Water Injection for NOx Reduction With Synthetic Liquid Fuels Containing High Fuel-Bound Nitrogen in a Gas Turbine Combustor
Authors: Mulik P. R. , Singh P. P. , Cohn A.
Published: April 2015

A total of five combustion tests utilizing water injection for control of NO, emissions have been conducted on three types of coal-derived liquid (CDL) fuels from the H-Coal and SRC II processes along with a shale-derived liquid (SDL) fuel supplied by the Radian Corporation. Actual testing was performed in a 0.14 m diameter gas-turbine-type combustor. For comparative purposes, each run with a synthetic liquid fuel was preceded by a baseline run utilizing No. 2 distillate oil. The effectiveness of water injection was found to decrease as the fuel-bound nitrogen (FBN) content of the synthetic liquids increased.
A Theory for Fine Particle Deposition in 2-D Boundary Layer Flows and Application to Gas Turbines
Authors: Agengiiturk M. , Sverdrup E. F.
Published: April 2015

A theory is presented to predict deposition rates offineparticles in two-dimensional compressible boundary layer flows. The mathematical model developed accounts for diffusion due to both molecular and turbulent fluctuations in the boundary layer flow. Particle inertia is taken into account in establishing the condition on particle flux near the surface. Gravitational settling and therm are not considered. The model assumes that the fraction of particles sticking upon arrival at the surface is known, and thus, treats it as a given parameter. The theory is compared with a number of pipe and cascade experiments, and a reasonable agreement is obtained. A detailed application of the model to a turbine is also presented. Various regimes of particle transport are identified, and the range of validity of the model is discussed. An order of magnitude estimate is obtained for the time the turbine stage can be operated without requiring cleaning.
Critical Materials: A New Dimension
Authors: Siegel M. A.
Published: April 2015

The decade of the ’80s was ushered in with a new dimension for designers, the availability of, and the meteoric cost increases of key materials. Though cost consciousness has always been a materials selection factor, current rates of increase make selection decisions more critical. Shortages of key metals such as cobalt, titanium, tantalum, molybdenum, and columbium, as well as potential problems with chromium and aluminum force the designer to carefully weigh his decisions. Questions of basic raw materials availability, metal conversion capacity, and the increasing influence of raw materials cost upon product cost must be considered. Vehicular gas turbine engine designers must evaluate materials selection decisions based upon these factors, and accompanying manufacturing processes to minimize input material requirements., Achieving high performance, with the required durability, at an acceptance cost is a bigger challenge than ever. This paper provides a view of the critical material situation and outlook, and typical options that are available.
Test Verification of Water Cooled Gas Turbine Technology
Authors: Horner M. W. , Cincotta G. A. , Caruvana A.
Published: April 2015

This paper presents the results of three significant tests recently performed by GE under the DOE High Temperature Turbine Technology Phase II Program contract. The first test involved a simulated Integrated Gasification Combined Cycle (IGCC) test of a water-cooled composite nozzle exposed to low Btu coal gas at design operating conditions (2600 F + firing temperature, 12 atm pressure). The second test is that of a water-cooled monolithic nozzle, a full-scale model of the second-stage nozzle planned for the Technology Readiness Vehicle Verification Test. The third test demonstrates coolant water delivery, transfer, and metering distribution, from the stationary feed line to the turbine rotor, enroute to individual bucket airfoil coolant passages. These tests successfully demonstrated the IGCC operation with very good results, and show every indication that operation at firing temperatures up to 3000 F is well within the design capability of the water-cooled turbine.
Interactive Multi-Mode Blade Impact Analysis
Authors: Alexander A.
Published: April 2015

This paper describes the theoretical methodology used in developing an analysis for the response of turbine engine fan blades subjected to soft body (bird) impacts and the computer program that was developed using this methodology as its basis. This computer program is an outgrowth of two programs that were previously developed for the purpose of studying problems of a similar nature (a three-mode beam impact analysis and a multi-mode beam impact analysis). The present program utilizes an improved missile model that is interactively coupled with blade motion which is more consistent with actual observations. It takes into account local deformation at the impact area, blade camber effects, and the spreading of the impacted missile mass on the blade surface. In addition, it accommodates plate-type mode shapes. The analysis capability in this computer program represents a significant improvement in the development of the methodology for evaluating potential fan blade materials and designs with regard to foreign object impact resistance.
Effects of Size and Reynolds’ Number on Centrifugal Diffuser Performance
Authors: Russo C. J. , Blair L. W.
Published: April 2015

The use of non-conventional diffusing systems for centrifugal compressors has been mandated by the smaller diameter of many advanced turbofan engines. Optimizing the design of these geometrically complex diffusers by rotating component tests is both expensive and time-consuming. Methods of designing and static blow testing low-diameter, controlled-contour passage diffusers have been previously reported in which scaled-up models of six diffuser passages were constructed and tested at a Reynolds number comparable to that encountered in rotating component tests. One design was fabricated in full size and run in both a static blow test and a rotating component test. This paper reports on the performance of this design at several Reynolds numbers up to those encountered in engine application for several diffuser throat blockages. It is shown that as with geometrically simpler passages such as conical diffusers, static blow tests can also be used to optimize the design of geometrically more complex diffusing passages.
Application of Airblast Atomizing Full Nozzles to Two Prototype Industrial Gas Turbines
Authors: McWhirter A. , Depooter K.
Published: April 2015

This paper describes the development history of the CW352 engine combustor from the time when the persistent problem of a hot primary zone wall when operating in the regenerative mode while burning diesel oil was solved by the incorporation of an airblast atomizer. The problems of stability and poor atomization at low engine cranking speeds which accompany the use of airblast atomizers were addressed in the combustion laboratory but evaluation tests on an engine showed that further improvement in these areas would be beneficial. Concurrently, the preliminary design strategy of the CW182 combustor was predicted on the use of an airblast atomizer and its development program emphasized a phase of testing which examined the effects on nozzle performance of variations in local flowfield and of the use of atomizing air. The paper documents the particular problems met and solved in the areas of burning oil fuel in a regenerative machine, of maintaining low emissions of smoke while designing for single inventory of parts and providing stable combustion by the use of auxiliary atomizing air.
Gas Turbine Data Acquisition Using a Microcomputer
Authors: Weston K. C.
Published: April 2015

A powerful, low cost, gas turbine data acquisition system capable of handling 24 or more channels of high and low level data is now in use at the University of Tulsa. The assembled system hardware, less transducers, is priced at about six thousand dollars and shows potential for further significant cost reduction. Easily programmed in the BASIC language, the microcomputer commands an analog-multiplexing digital voltmeter, decodes the resulting serial data, and performs conversion to engineering units. It also processes data for display on a color television monitor, for storage on diskette, and for transcription on a printer. Examples, showing gas turbine performance, clearly portray the power of the general purpose microcomputer in an engineering data acquisition system and its potential for engineering education.
Forging Simulations and Properties Achievable for Large Waspaloy Forgings for Land-Based Gas Turbines
Authors: Shah S. N. , Monti G. J.
Published: April 2015

This paper describes a computer simulation technique used to analyze the heat transfer and deformation encountered during various forging and heat treatment operations of a large Waspaloy forging for a land-based gas turbine. Using the same processing cycle on a sub-scale forging, it was possible to predict the property levels obtainable in the original forging. The subscale data are compared with the properties evaluated from a cut-up of a full-size forging showing good agreement. The tensile and stress rupture property levels achievable in the large forgings and the influence of processing variables on them are presented in this paper. Also presented are the data on the heat treat response for various section sizes.
Use of a Tracer Gas Technique to Study Mixing in a Low Speed Turbine
Authors: Denton J. D. , Usui S.
Published: April 2015

A method of using a flame ionization detector to study the movement of air containing a small concentration of ethylene is described. Ethylene is chosen because it has almost the same density as air so buoyancy effects are negligible. The technique is applied to flow in a bent duct and in a low speed air turbine. In both cases large scale migrations of the end wall boundary layers onto the suction surfaces are observed. However, in the turbine the span wise movement and mixing of the flow at mid-span is remarkably small.
Measurement of Heat Flux and Pressure in a Turbine Stage
Authors: Dunn M. G. , Hause A.
Published: April 2015

Selected portions of the first-stage stationary inlet nozzle, shroud, and rotor of the AiResearch TFE 731-2 turbine were instrumented with thin-film heat-transfer gages and heat-flux measurements were performed using a shock tunnel as a source of high-temperature, high-pressure gas. Experiments were performed over a range of Reynolds numbers, based on mid-annular stator chord, from 1.6 × 105 to 3.1 × 105 and corrected speeds from approximately 70 to 106 percent. The full-stage heat-flux results are compared to our previous measurements obtained with a stator only, in the absence of a rotor. The previous results are in good agreement with the full-stage data for the tip end-wall region, but they are significantly less than the full-stage results for the stator airfoil. Pressure measurements were obtained throughout the model and these results are shown to be in excellent agreement with the steady-state rig data supplied to us by AiResearch for this turbine. Heat-flux measurements are also presented for the stationary shroud as a function of rotor mid-annular chord. The shroud heat flux data are shown to be in excess of the rotor blade results. Rotor-tip heat flux measurements are likewise shown to be slightly greater than the shroud results.
Some Modifications to, and Operational Experiences With, the Two-Dimensional, Finite-Difference, Boundary-Layer Code, STAN5
Authors: Gaugler R. E.
Published: April 2015

The two-dimensional, finite-difference boundary-layer code, STAN5, is the primary tool used at the NASA-Lewis Research Center for predicting turbine blade gas-side heat-transfer coefficients. A number of modifications have been made to the program to enhance its usefulness for these calculations. Experience in using STAN5 has identified some problems in the program that can be treated through program input, without modifying the program. These include the presence of a small separation bubble near the leading edge, and the effect of full-coverage film cooling on transition to turbulence. Some of the techniques used to treat these problems are described.
Heat Transfer in a Periodic Boundary Layer Near an Axisymmetric Stagnation Point on a Circular Cylinder
Authors: Gorla R. S. R. , Jankowski F. , Textor D.
Published: April 2015

An analysis is presented to investigate the time-mean characteristics of the laminar boundary layer near an axisymmetric stagnation point when the velocity of the oncoming flow relative to the body oscillates. Different solutions are obtained for the small and high values of the reduced frequency parameter. Numerical solutions for the velocity and temperature functions are presented and the wall values of the velocity gradients and temperature gradients are tabulated.
Experimental Determination of Transition Reynolds Number for Unsteady Film Cooling
Authors: Tsou F. K. , Smith L. T. , Chen S. J.
Published: April 2015

In order to investigate the unsteady effect on transition in film cooling, an 11-m long Ludwieg Tube, consisting of a test section placed between the high pressure and low pressure sections of a shock tube, has been constructed. With this device, a controlled unsteady, low subsonic flow lasting for a period of several milliseconds is obtained. The transition Reynolds Number is determined from the output of thin film heat flux transducers having a response time of a fraction of a microsecond. The results indicate that, in the case of flow without gas injection into the boundary layer, the transition Reynolds Number is one order of magnitude smaller than the critical Reynolds Number for steady wedge flow with the same pressure gradient. With injection, the transition Reynolds Number is small near the injection slot; far downstream, it increases asymptotically to the value for flow without injection.
NASA Research in Aeropropulsion
Authors: Stewart W. L. , Weber R. J.
Published: April 2015

Future advances in aircraft propulsion systems are aided by the research performed by NASA and its contractors. This paper reviews selected examples of recent accomplishments and current activities that are relevant to the principal classes of civil and military vehicles: subsonic transports, commuters, supersonic transports, general aviation, rotorcraft, V/STOL, and high-performance. Some instances of new emerging technologies with potential high impact on further progress are discussed.
Low NOx and Fuel Flexible Gas Turbine Combustors
Authors: Lew H. G. , DeCorso S. M. , Vermes G. , Carl D. , Havener W. J. , Schwab J. , Notardonato J.
Published: April 2015

The work described in this paper is a part of the DOE/ LeRC “Advanced Conversion Technology Project” (ACT). The program is a multiple contract effort with funding provided by the Department of Energy, and technical program management provided by NASA LeRC. Testing has been done burning a petroleum distillate fuel (ERBS fuel), a coal derived fuel (SRC II middle distillate), a petroleum residual fuel, and various blends of these fuels. Measurements are made of NOx CO, and UHC emissions, and other measurements are made to evaluate combustor performance. Results to date indicate that rich-lean diffusion flames, with low fuel bound nitrogen conversion, are achievable with very high combustion efficiencies.
A Radial Inflow Turbine Impeller for Improved Off-Design Performance
Authors: Mulloy J. M. , Weber H. G.
Published: April 2015

Given the instantaneous operating conditions of the radial inflow turbine on a diesel engine and the possible requirement of a variable geometry turbine casing, an alternate approach was used to design an impeller which could accommodate the large variations in inlet states. Several impeller designs were generated and tested. Each was found to give a performance advantage in some portion of the turbine map. A blunt inlet shape design was found to give the best performance at all suspected inlet conditions. A final design turbine wheel was generated to cover the operating range of a variable geometry turbine casing. It was found that this impeller gave improved efficiencies at all operating conditions.
Influence of Casing Treatment on the Operating Range of Axial Compressors
Authors: Paulon J. , Dehondt D.
Published: April 2015

Experimental investigations brought to light the possibilities of broadening the operating range of axial flow compressors by means of outer wall casing treatments such as grooves, honeycombs or cavities. The industrial use of these techniques is however limited by uncertainties on the effectiveness of these treatments as, while they are very beneficial in some cases, they deteriorate the performance of the machine in some others. A theoretical investigation has been conducted on the flow field in cavities most commonly used, and laws for determining the groove depth have been established which account for the surge margin improvement obtained in some cases and make it possible to dismiss inefficient geometric configurations. A comparison between theory and experiment is presented, based on test results published in the literature and on an experimentation on two industrial compressors.
Repair Techniques for Hot Gas Path Components in Industrial Gas Turbines
Authors: Dodgson J. S.
Published: April 2015

The methods used to repair turbine components from Industrial gas turbines are reviewed and explained. Particular reference is made to cleaning, heat treatments, welding, brazing, machining, coatings and inspection.
Cryogenic Turbine Testing
Authors: Iannuzzelli R. J. , Filippi R. E.
Published: April 2015

Machinery testing in a cryogenic environment poses special instrumentation and data acquisition difficulties. The test engineer can spend much of his time diagnosing and correcting problems before valid test data can be obtained. This paper will address the problems encountered in establishing a turbomachinery test program and the eventual solutions. Data accuracy will also be presented for various tests.
Design and Fabrication of Composite Water-Cooled Turbine Nozzles
Authors: Muth M. , Klompas N.
Published: April 2015

This paper presents an account of the mechanical design and the fabrication development required to produce the functional nozzle segment of a gas turbine generator operated with coal-derived fuels at a firing temperature of 2600°F (1426°C). The nozzle is water cooled by a closed loop system. It is constructed of a composite of materials which have been totally diffusion bonded by means of the Hot Isostatic Pressing (HIP) process. Several segments have been made. These segments will be tested late in 1980.
Modern Base Load Gas Turbines Running on Crude Oil: Long Time Effects and Experience
Authors: Basler B. , Felix P. C.
Published: April 2015

Crude oils are favorable gas turbine fuels, particularly in areas where light crudes are available and distillates in sufficient quantities are difficult to obtain. In Riyadh, Saudiarabia, local Khurais crude oil is therefore certainly the most reasonable gas turbine fuel. This paper shows the long time experience with this type of fuel gathered in ten modern BBC type 11 turbines with a total of over 100,000 operating hours. The main problems and the measures taken to overcome these problems are described in detail. The operational record of the Riyadh 5 power plant of the last three years demonstrates that it is possible to run a powerplant without any diesel oil for blending or start up, e.g., and still to obtain availability and reliability numbers which are as good or better than for a diesel or gas fired plant.
Numerical Study of Liquid Cooling Gas Turbine Blade
Authors: Amano R. S.
Published: April 2015

Numerical study is reported of a turbulent flow and a convective heat transfer rate around a gas turbine blade. In the computation of turbulent flow, a hybrid method of the central and the upwind finite differencing is used with the standard k-e turbulence model. The quasi-linear transformed coordinate is adopted for a grid system. For the computation of wall boundaries, the wall function is based on the idea that, beyond the viscous sublayer, the turbulent length scale is universal, increasing linearly with distance from the wall. The computed results display more effects of free stream turbulence level on the suction side where a strong favorable pressure gradient takes place than on the pressure side. The model illustrated here shows results superior to the analytic solution as a whole.
A Mixed-Flow Cascade Passage Design Procedure Based on a Power Series Expansion
Authors: Novak R. A. , Haymann-Haber G.
Published: April 2015

Flow passage design and analysis procedures employing a Taylor series expansion across the flow field were first suggested as far back as 1908. With very few exceptions the early work addressed only the problem of symmetrical convergent-divergent passages. A generalization and an extension of the approach permits it to be used for the design of arbitrary cascade passages in subsonic, supersonic, or mixed-flow regimes. The method will give fast, realistic solutions in situations where shock-freeflow is meaningful, and where the cascade gap-chord ratio is not excessive. It assumes inviscid, irrotational flow and employs a fourth-order Taylor series expansion across the cascade passage. Numerous examples are given, with comparisons with experimental data and other analytic solutions.