bluuebunny/crossref_metadata_2025 huggingface dataset:
Current Status of Ceramic Gas Turbine R&D in Japan
Authors: Yamagishi Kiichiro , Yamada Yukio , Echizenya Yoshihiro , Ishiwata Shoji
Published: March 2015

The Japanese Ministry of International Trade and Industry (MITI) has started two nine-year national R&D projects for small-capacity ceramic gas turbines (CGTs) from 1988, following several preliminary investigations of the technical aspects and of the social impacts of CGTs.

Planned 300kW industrial ceramic gas turbines are to be used for co-generation and mobile power generation. The goals are 42% and higher for the thermal efficiency at the turbine inlet temperature of 1350°C, and the emission from the exhaust gas should meet the regulatory values. Also ceramic components have the goals of 400MPa for the minimum flexure strength at 1500°C, and 15 MPam1/2 for the fracture toughness. New Energy and Industrial Technology Development Organization (NEDO) is the main contractor, and three groups of private industries are the subcontractors for 300kW industrial CGT project. Three national research institutes are involved in the projects to conduct supportive research of ceramic materials and engine components as well as to carry out assessment of the materials and engine systems developed by the private industries.

The development of 100kW CGT for automotive use was also recommended in the above stated investigations and a two-year preliminary study started in 1988. The full-scale 100kW automotive CGT R&D project is scheduled to start in 1990 after the preliminary study. Japan Automobile Research Institute, Inc. (JARI) is the main contractor for 100kW automotive CGT project with the cooperation of three automobile companies.
A Direct Coal-Fired 80 MW Utility Combustion Turbine-Status Report
Authors: Diehl R. C. , Stickler D. B. , Loftus P. J. , Bannister R. L. , Pillsbury P. W.
Published: March 2015

The objective of this effort is to establish the technology required for private sector use of an advanced coal-fueled gas turbine power system. The system is to burn low-cost, utility-grade coal, and yet comfortably meet the EPA New Source Performance Standard (NSPS) for coal-fired steam generators. Plant thermal efficiency is to surpass competing coal-utilization cycles.

Development of a successful high pressure slagging combustor is the key to meeting these objectives. As subcontractor to Westinghouse, Avco Research Laboratory/Textron (ARL) has designed and fabricated a subscale slagging combustor based on earlier MHD and boiler-type units. The new device is currently in a 12½-month developmental series of tests. Based on these series of tests, Westinghouse is to design, manufacture, and test a full-scale slagging combustor in a test cell at nominal field operating conditions. The activities described in this paper are sponsored by the Morgantown Energy Technology Center of the Department of Energy.
Study of Various Factors Affecting Secondary Loss Vortices Downstream a Straight Turbine Cascade
Authors: Mobarak A. , Khalafallah M. G. , Heikal H. A. , Osman A. M.
Published: March 2015

An experimental investigation is carried out to study the effect of inlet boundary layer thickness, aspect ratio and exit Mach number on the energy loss and on the behaviour of secondary vortices downstream of a straight turbine cascade of blades having 82° turning angle.

Some correlations were deduced which predict, the cascade efficiency and the gross secondary loss coefficient as function of the downstream distance.
Probabilistic Structural Analysis Methods of Hot Engine Structures
Authors: Chamis C. C. , Hopkins D. A.
Published: March 2015

Development of probabilistic structural analysis methods for hot engine structures is a major activity at Lewis Research Center. It consists of three program elements: (1) composite load spectra methodology, (2) probabilistic structural analysis methodology, and (3) probabilistic structural analysis application. Recent progress includes: (1) quantification of the effects of uncertainties for several variables on High Pressure Fuel Turbopump (HPFT) turbine blade temperature, pressure, and torque of the Space Shuttle Main Engine (SSME), (2) the evaluation of the cumulative distribution function for various structural response variables based on assumed uncertainties in primitive structural variables, and (3) evaluation of the failure probability. Collectively, the results demonstrate that the structural durability of hot engine structural components can be effectively evaluated in a formal probabilistic/reliability framework.
Bond Coat Development for Thermal Barrier Coatings
Authors: Wortman David J. , Duderstadt Edward C. , Nelson Warren A.
Published: March 2015

The use of thermal barrier coatings on high pressure turbine components can improve gas turbine efficiency through reduction of cooling airflow. However, to reduce cooling airflow, a highly reliable thermal barrier coating is required. This increased reliability will be achievable through several complimentary approaches: material and process development, life prediction method development and engine service experience. The results of bond coat material development which has increased the thermal cycle life of plasma spray thermal barrier coatings are presented. Improvements were achieved by two methods; 1) use of creep resistant bond coat compositions and 2) overaluminiding of the bond coat.
A Three Dimensional Inverse Method in Turbomachinery: Part II — Experimental Verification
Authors: Borges João Eduardo
Published: March 2015

The performance of an impeller of a low-speed radial-inflow turbine, designed using a three-dimensional inverse technique was evaluated experimentally. This performance was compared with that achieved by a rotor typical of the present technology. Besides measuring over all quantities, in special efficiency, some traverses of flow velocity were carried out. The results of the test-showed that the new design had a peak total-to-static efficiency 1.4 points better than the conventional build. The traverses indicated that the level of swirl at exhaust of the new impeller was only half as big as that for the conventional rotor, in spite of the fact that both impellers were designed to have zero swirl at outlet. It is also shown that the rotor loss for the new impeller is considerably lower than for the conventional wheel. This research points to the desirability of using a three-dimensional inverse method for the design of turbomachines with significant three-dimensional flows.
Site Performance Testing of CW251B10 Gas Turbines
Authors: Diakunchak Ihor S. , Nevin David R.
Published: March 2015

The site performance testing of CW251B10 industrial gas turbine engines is described in this paper. A brief description is provided of the test procedure, the special instrumentation used during the test, and the derivation of the test tolerances. The test data analysis method and the associated correction curves and tables are described in some detail. Typical engine site performance test results are presented and compared to the original predicted engine performance.
Some Composite Bearing and Seal Materials for Gas Turbine Applications: A Review
Authors: Sliney Harold E.
Published: March 2015

A review is given of the selection and tribological testing of materials for high-temperature bearings and seals. The goal is to achieve good tribological properties over a wide range of temperatures because bearings and seals must be functional from low temperature start-up conditions on up to the maximum temperatures encountered during engine operation. Plasma sprayed composite coatings with favorable tribological properties from 25 to 900 °C are discussed. The performance of these coatings in simple tribological bench tests is described. Examples are also given of their performance in high-speed sliding contact seals, as Stirling cylinder liner materials, and as back up lubricants for compliant foil gas bearings.
Control System for a Combined Cycle
Authors: Maderni L. , Fontana M. , Icardi G.
Published: March 2015

The paper describes the organization and the architecture of the digital control system for the combined cycle of FIAT Mirafiori power plant.

The choice of functions subject to automatic control is connected to the features required such as:

- automatic start-up with steam turbine as prime mover;

- operation of the cicle either in parallel or in “island” mode with regard to the national grid;

- sliding pressure on the steam generation side, for higher cycle efficiency;

In order to take into account interactions between the different equipment in the definition of the control functions, the behaviour of the whole cycle physical variables has been examined by a digital dynamic simulation.
A Thermodynamic Analysis of the Kalina Cycles: Comparisons, Problems and Perspectives
Authors: Stecco Sergio S. , Desideri Umberto
Published: March 2015

The paper presents a second-law and thermodynamic analysis of the Kalina cycle, aiming at discovering the effects of the composition of the working fluid, of the temperature of the exhaust gases, and of the boiler pressure.

Recent investigations of Kalina (1988) and El-Sayed (1985b) are completed with an overall analysis of exergetic losses in various working situations.

An original computer program KALCYC has been developed for this purpose.

The results have shown the very high exergetic efficiency and specific power that the Kalina cycle can provide, and the possibility of an optimization for each available heat source.

A brief comparison has also been made with the Rankine cycle as far as practical advantages are concerned.
A New Design Method for Centrifugal Compressor Varied Diffusers
Authors: Xiaoyan Huang , Qinghuan Wang , Chao Zhang
Published: March 2015

In order to develop a CAD computer code system for centrifugal compressor, a numerical technique for design and flow analysis of vaned diffusers has been introduced in this paper. The design of diffusers has been performed by a streamline extension method. The velocity and pressure distributions at design and off-design operating modes have been calculated by a time-dependent finite difference scheme and have been corrected by boundary layer calculations. The numerical results are compared with experimental measurements, and the agreement is satisfactory.
The Design and Test of a Two Stage Transonic Axial Flow Compressor
Authors: Wells R. G. , Baty G. , Carchedi F. , Wood G. R.
Published: March 2015

The design of the transonic stages, which form the front two stages of a multi stage compressor, is described. The first stage tip Mach No. is 1.1.

The test programme to evaluate the performance of the two stages is outlined and detailed results of the overall and stage performance are presented. Details of the flow field from traverse measurements and the over tip shock structure obtained from high response pressure transducers are compared with predictions.

Strain Gauge results taken from the rotating blades are also presented.
Repair and Life Extension of Titanium Alloy Fan Blades in Aircraft Gas Turbines
Authors: Patnaik P. C. , Pishva M. R. , Elder J. E. , Doswell W. , Thamburaj R.
Published: March 2015

Commercial and military aircraft gas turbine fan blades can suffer various types of damage in service, such as foreign object damage (FOD), high strain low cycle fatigue (LCF), wear and fretting fatigue. In addition, cracks initiated by one or more of these types of damage may propagate by a high cycle fatigue (HCF) mechanism. The component may therefore be life limited by the dominant failure mechanism.

In this paper, a new, comprehensive scheme for economical refurbishment and qualification of service damaged titanium alloy fan blades is described, along with a critical review of the merits and demerits of existing repair schemes. The metallurgical and process variables to be considered in the repair of FOD, LCF life extension, wear and fretting fatigue life improvement are considered in detail with practical examples derived from experience.

A complete qualification testing program including metallography, non-destructive inspection and mechanical property testing, for the refurbished component is outlined.
Improvement of 3D Full-Potential Method and Computation of Flowfield of CAS Compressor Rotor
Authors: Jialin Zhang
Published: March 2015

The present study is aimed at improving the 3D (three-dimensional) full-potential method for solving the 3D flowfield in turbomachines. The improvement made is in two areas. First, a flow loss has been simulated with the entropy distribution along streamlines and introduced into the solution for gas density. Second, the viscous effect of the flow near boundaries has been modeled with a displacement thickness distribution of the boundary layers along the hub, the shroud, the blade surfaces, and the vortex sheets in the wakes of blades and introduced into the computation of the 3D flowfield. Since this improved 3D full-potential method incorporated some effects in the real flow in turbomachines, it can be applied to some complicated engineering problems with satisfactory results. In the present work, the improved 3D full-potential method has been used to compute the 3D flowfield in the compressor rotor of CAS (Chinese Academy of Sciences) at 60% design rotational speed. Some computed results are shown in this paper.
A Theoretical Study of Ingress for Shrouded Rotating Disc Systems With Radial Outflow
Authors: Chew John W.
Published: March 2015

Sealing of the cavity formed between a stationary disc and a rotating disc under axisymmetric conditions is considered. A mathematical model of the flow in the cavity based on momentum integral methods is described and this is coupled to a simple model of the seal for the case when no ingress occurs. Predictions of the minimum imposed flow required to prevent ingress are obtained and shown to be in reasonable agreement with the data of Bayley and Owen (1970), Owen and Phadke (1982), Phadke (1982), and Phadke and Owen (1982, 1983, 1988). With an empirical constant in the model chosen to match this data predictions for the minimum sealing flow are shown to be in good agreement with Graber et al’s (1987) measurements. The analysis of Phadke’s data also indicates the measurements for small seal clearances must be viewed with caution due to errors in setting the seal clearance. These errors are estimated to be twice the minimum clearance considered. Seal behaviour when ingress occurs is also considered and estimates of the amount of ingress are made from the available data.
Assessment of Laminar-Turbulent Transition in Closed Disc Geometries
Authors: Morse A. P.
Published: March 2015

Finite-difference solutions are presented for rotationally-induced flows in the closed space between two coaxial discs and an outer cylindrical shroud, in which there is no superimposed flow. The solutions are obtained with an elliptic-flow calculation procedure and an anisotropic low turbulence Reynolds number k-ε model for the estimation of turbulent fluxes. The transition from laminar to turbulent flow is effected by including in the energy production term a small fraction (0.002) of the ‘turbulent viscosity’ as calculated from a simple mixing length model. This level for the artificial energy input was chosen as that appropriate for transition at a local rotational Reynolds number of 3 × 105 for the flow over a free, rotating disc.

The main focus of the paper is the rotor-stator system, for which the influence of rotational Reynolds number (over the range 105–107) is investigated. Predicted velocity profiles and disc moment coefficients show reasonably good agreement with available experimental data. The computational procedure is then extended to cover the cases of corotating and counter-rotating systems, with variable relative disc speed.
An Experimental Study of Heat Transfer and Film Cooling on Low Aspect Ratio Turbine Nozzles
Authors: Takeishi K. , Matsuura M. , Aoki S. , Sato T.
Published: March 2015

The effects of the three-dimensional flow field on the heat transfer and the film cooling on the endwall, suction and pressure surface of an airfoil were studied using a low speed, fully annular, low aspect h/c=0.5 vane cascade.

The predominant effects that the horseshoe vortex, secondary flow, and nozzle wake increases in the heat transfer and decreases in the film cooling on the suction vane surface and the endwall were clearly demonstrated. In addition, it was demonstrated that secondary flow has little effect on the pressure surface. Pertinent flow visualization of the flow passage was also carried out for better understanding of these complex phenomena. Heat transfer and film cooling on the fully annular vane passage surface is discussed.
Effects of an Embedded Vortex on Injectant From a Single Film-Cooling Hole in a Turbulent Boundary Layer
Authors: Ligrani P. M. , Williams W.
Published: March 2015

Effects of embedded longitudinal vortices on heat transfer in turbulent boundary layers with injection from a single film cooling hole are described. These results were obtained at a freestream velocity of 10 m/s, with a film cooling hole inclined 30 degrees to horizontal and a blowing ratio of about 0.50. The ratio of vortex core diameter to injection hole diameter was 2.14, and the ratio of circulation to injection velocity times hole diameter was about 2.8. Coolant distributions and spatially resolved heat transfer measurements indicate that injection hole centerlines must be a least 2.0–2.5 vortex core diameters away from the vortex center in the lateral direction to avoid significant alterations to wall heat transfer and distributions of film coolant. Under these circumstances, protection from film cooling is evident at least up to 55 hole diameters downstream of injection. When the injection hole is closer to the vortex center, secondary flows convect most injectant into the vortex upwash and thermal protection from film cooling is destroyed for streamwise locations from the injection hole greater than 17.5 hole diameters.
A Comparative Investigation of Corresponding Annular and Labyrinth Seal Flowfields
Authors: Rhode D. L. , Hibbs R. I.
Published: March 2015

A previous Navier-Stokes finite difference computer code is extended in order to compute seal leakage directly from given upstream and downstream reservoir pressures. The numerical results are in excellent agreement with previous measurements, the discrepancy being less than eight percent. Annual seals are found to leak approximately twenty percent more than corresponding labyrinths over the entire range of realistic clearance. A rather unexpected finding is that a dramatic increase of swirl velocity occurs near the discharge of small clearance annular seals, which does not arise in corresponding labyrinth seals. The results, which are used to explain this finding, show that a large density drop occurs near the small clearance annular seal exit, which provides the swirl velocity increase in accordance with angular momentum conservation.
The Effects of Steam Injection in Combustion Air on the Thermal Efficiency and the Specific Work Output of a Stationary Gas Turbine Plant
Authors: Varma K. S. , Khandwawala Asgharali I. , Asif S. A.
Published: March 2015

In the present study a stationary open cycle gas turbine plant, including a thermal regenerator has been theoretically analyzed to assess the impact of steam addition in combustion air, on its performance. the effect of varying steam upto 15% air at different pressure ratios and turbine inlet temperatures have been reported. Mixing of steam in air results in higher values of cycle efficiency and increased specific work output, feasibility to generate steam needed for the purpose in a waste heat boiler have also been studied.
Application of a Lower-Upper Implicit Scheme and an Interactive Grid Generation for Turbomachinery Flow Field Simulations
Authors: Choo Yung K. , Soh Woo-Yung , Yoon Seokkwan
Published: March 2015

A finite-volume lower-upper (LU) implicit scheme is used to simulate an inviscid flow in a turbine cascade. This approximate factorization scheme requires only the inversion of sparse lower and upper triangular matrices, which can be done efficiently without extensive storage. As an implicit scheme it allows a large time step to reach the steady state. An interactive grid generation program (TURBO), which is being developed, is used to generate grids. This program uses the control point form of algebraic grid generation which uses a sparse collection of control points from which the shape and position of coordinate curves can be adjusted. A distinct advantage of TURBO compared with other grid generation programs is that it allows the easy change of local mesh structure without affecting the grid outside the domain of dependence. Sample grids are generated by TURBO for a compressor rotor blade and a turbine cascade. The turbine cascade flow is simulated by using the LU implicit scheme on the grid generated by TURBO.
Axial Flow Compressor Design Optimization: Part I — Pitchline Analysis and Multivariate Objective Function Influence
Authors: Massardo Aristide , Satta Antonio
Published: March 2015

The design of an axial flow compressor stage has been formulated as a nonlinear mathematical programming problem with the objective of minimizing the aerodynamic losses, and the weight of the stage while, maximizing the compressor stall margin. Aerodynamic as well as mechanical constraints are considered in the problem formulation. A method of evaluating the objective function and constraints of the problem with a pitchline analysis is presented. The optimization problem is solved by using the penalty function method in which the Davidon-Fletcher-Powell variable metric minimization technique is employed. Designs involving the optimization of efficiency, weight of the stage, and stall margin are presented and the results discussed with particular reference to a multivariable objective function.
Axial Flow Compressor Design Optimization: Part II — Through-Flow Analysis
Authors: Massardo Aristide , Satta Antonio , Marini Martino
Published: March 2015

A new technique is presented for the design optimization of an axial-flow compressor stage. The procedure allows for optimization of the complete radial distribution of the geometry since the variables, chosen to represent the three dimensional geometry of the stage, are coefficients of suitable polynomials. Evaluation of the objective function is obtained with a through-flow type calculation, which has acceptable speed and stability qualities. Some examples are given of the possibility to use the procedure both for redesign and, together with what was presented in Part I, for the complete design of axial-flow compressor stages.
Chemical Aspects of Deposition/Corrosion From Coal-Water Fuels Under Gas Turbine Conditions
Authors: Wenglarz Richard A. , Fox Ralph G.
Published: March 2015

A staged, subscale turbine combustor based on a promising rich-quench-lean combustor approach to reduce NOX emissions was used to evaluate deposition, erosion, and corrosion (DEC) from coal-water fuels (CWF). This combustor was operated with three CWF at conditions of a recuperated turbine. Specimens were exposed in two test sections at temperature conditions of the first stator vanes and first rotor blades of the recuperated turbine. Resulting deposits were chemically analyzed. Deposit covered segments of specimens were placed in a furnace to extend their exposure to the potentially corrosive deposits.

The deposits produced at higher temperature first stator conditions differed significantly from those produced at lower temperature first rotor conditions. The rates of formation of the higher temperature deposits were high and the deposit chemistries were similar to the coal ash chemistry. The rates of formation of the lower temperature deposits were one to two orders of magnitude less and deposit chemistries were not the same as the coal ash chemistry. Some corrosion of a CoCrAlY coating was detected after a few hours of exposure in the DEC tests. Corrosion penetration up to one-half of the coating thickness was observed after an additional 460 hr furnace exposure. Much more testing is needed to explore whether the deposition and corrosion produced by the fuels evaluated are typical of this fuel form and to assess benefits of alternate turbine protection measures.
Some Aerodynamic Aspects of Engine Secondary Air Systems
Authors: Zimmermann H.
Published: March 2015

Internal cooling air systems of turbomachines contain various fluid flow components, i.e. rotating holes, tapping configurations, coverplates, labyrinth seals etc., for which only the basic aerodynamics are known. Numerical calculations for these elements are carried out and compared with test results showing fair agreement in general.

For most of the components of internal air systems there is a serious lack of test data. It is shown that the situation can be relieved by applying numerical methods, which should also be used to improve and extend the empirical correlations in the air systems computer programs.
The Extension and Application of Three-Dimensional Time Marching Analyses to Incompressible Turbomachinery Flows
Authors: Walker P. J. , Dawes W. N.
Published: March 2015

Conventional time marching flow solvers perform poorly when integrating compressible flow equations at low Mach numbers levels. This is shown to be due to unfavourable interaction between long wavelength errors and the inflow and outflow boundaries. Chorin’s method of artificial compressibility is adopted to extend the range of Denton’s inviscid flow solver and Dawes’ three-dimensional Navier-Stokes solver to zero Mach number flows. The paper makes a new contribution by showing how to systematically choose the artificial acoustic speed to optimize convergence rate with regard to the error wave-boundary interactions. Applications to a turbine rotor and generic water pump geometry are presented.
Design and Performance of a Small Power Clausius-Rankine Process
Authors: Shao Z. , Malobabic M. , Burhorn D. , Rautenberg M.
Published: March 2015

In recent years, an increasing awareness of the shortness of raw materials has led to an improved utilization of the energy input in thermal processes. Utilization of the heat generated in such processes and machinery can improve the overall efficiency of the latter and converse raw materials. In particular, combustion engines have a poor overall efficiency due to the high temperature exhaust gases which they produce. The classical Clausius-Rankine process can be applied to such machines in order to utilize the heat generated so as to provide turbocharging of the latter. The design of such a Clausius-Rankine process in connection with a newly-developed steam turbine based upon the Pelton principle is presented. In this design, particular value is placed upon the small size of individual units and a comparability with actual thermodynamic conditions in combustion engines.
Parametric Analysis of the Kalina Cycle
Authors: Marston Charles H.
Published: March 2015

The Kalina Cycle utilizes a mixture of ammonia and water as the working fluid in a vapor power cycle. When the liquid mixture is heated the more volatile ammonia tends to vaporize first and at a lower temperature than does pure water. This property of ammonia-water mixtures makes possible a better match to the enthalpy-temperature curve of a hot gas heat source such as a gas turbine exhaust and also permits circulation of fluids of different composition in different parts of the cycle. Taking advantage of the latter feature, condensation (absorption) can be done at slightly above atmospheric pressure with a low concentration of ammonia, while heat input is at a higher concentration for optimum cycle performance.

Computer models have been used to optimize a simplified form of the cycle and to compare results for a more complex version proposed by El-Sayed and Tribus. A method of balancing the cycle was developed and key parameters for optimizing the cycle identified.
Advanced Compressed Air Energy Storage Concepts With Utilization of the Low Pressure Expander Exhaust Gas Heat for Steam Generation
Authors: Nakhamkin M. , Swensen E. , Schainker R. B. , Pollak R.
Published: March 2015

A number of analyses concluded that in order to be cost effective a compressed air energy storage (CAES) plant should have a recuperator, which recovers the low pressure (LP) expander’s exhaust gas heat for preheating the cold cavern air before it enters the high pressure (HP) combustor(s). The use of a recuperator reduces heat rate, and accordingly fuel consumption, by as much as 20–25%. Therefore all feasibility studies on CAES performed for various utilities included a recuperator, and the first CAES plant to be built in the U.S., the 110 MW CAES plant for the Alabama Electric Cooperative (AEC) will utilize a recuperator with a 75% effectiveness.
Flexible Couplings for Gas Turbine Applications
Authors: Mancuso Jon R.
Published: March 2015

The gear coupling was the primary flexible coupling for industrial gas turbines for almost twenty-five years. As advancements in the industrial gas turbine have occurred so have advancements in gear couplings. There are many variables in gear couplings that can affect their characteristics, including tooth design, materials, and lubrication methods. All couplings react on connected equipment. The system designer must consider these reactions when designing the system. If a gear coupling is chosen, there are many characteristics which can make a designer’s life easier. This paper compares the characteristics of diaphragm couplings versus gear type couplings used in industrial gas turbine applications including applications of couplings for turbine to generator, turbine to mechanical drives (compressors, pumps, and gear) and also couplings used between the turbine and accessory gears. The methods used to analyze the design and the forces and moments generated by both the gear coupling and the diaphragm coupling are also provided. These analysis are used to show that the forces and moments generated by a diaphragm coupling are not only predictable, but usually lower than those of a gear coupling. The paper shows that a diaphragm coupling can be more predictable and reliable than a gear coupling for most industrial gas turbine applications.
Aerodynamic and Heat Transfer Measurements on Blading for a High Rim-Speed Transonic Turbine
Authors: Kingcombe R. C. , Harasgama S. P. , Leversuch N. P. , Wedlake E. T.
Published: March 2015

A high rim speed turbine, incorporating some 3-D features has been designed and tested at RAE Pyestock. There has been cold flow turbine testing, with overall performance measurements, rotor exit traversing as well as surface static pressure measurements on the vane and rotor. The vane has also been tested in annular cascade on the Isentropic Light Piston Cascade giving surface heat transfer measurements on the vanes and endwalls as well as aerodynamic information.

The data have been used to compare with design predictions and the reasons for the differences observed, particularly on the rotor blade, are explored.
An Analysis of Outlet Distortion in LP Steam Turbines
Authors: Moser W.
Published: March 2015

In gas and steam turbines, outlet distortions may lead to vibrations of the rotor blades. In order to gain a deeper understanding of origin and intensity of the excitation mechanism, various distorted flow conditions caused by asymmetric exhaust or by ribs were investigated in radial and circumferential direction with the help of pneumatic probes. The periodic pressure fluctuations on the rotor blades, which are responsible for the excitation, were determined with miniature pressure transducers at temperatures of about 100 °C and centripetal accelerations of 65,000 g. The response of the blades was measured by strain gauges. The results obtained can be used for verification of three-dimensional unsteady flow algorithms.
Rainbow Field Test of Coatings for Hot Corrosion Protection of Gas Turbine Blades and Vanes: I — Blade Coatings
Authors: Van Roode Mark , Aurrecoechea Jose
Published: March 2015

A rainbow field test sponsored by the Electric Power Research Institute (EPRI) under contract RP2465-1 was performed to evaluate the comparative hot corrosion resistance of commercially available coatings for gas turbine blades and vanes. The 10,307-hr field test was carried out on a Solar Turbines Incorporated Centaur T-4000 gas turbine operating on a lower grade liquid fuel at the Favianca site of the Owens-Illinois, Inc. glass manufacturing facility in Valera, Venezuela. This paper reviews the results of an evaluation of the performance of three modified aluminides, three MCrAlY overlays, and one duplex NiCoCrAlY/ZrO2-2OY2O3 overlay applied as coatings to the first-stage MAR-M421 and IN-738LC rotor blades, Visual and metallographic examination and remnant coating thickness measurements established that the MCrAlY overlay coatings were generally more effective than a Cr-aluminide and two Pt-aluminides protecting the first-stage blades. Individual differences between the various coatings were established. A remnant coating thickness index (RCTI) was defined to express coating survival and protectiveness quantitatively. The results of blade airfoil temperature estimates were correlated with the hot corrosion morphology.
Rainbow Field Test of Coatings for Hot Corrosion Protection of Gas Turbine Hot Section Components: II — Vane Coatings
Authors: Van Roode Mark
Published: March 2015

A rainbow field test sponsored by the Electric Power Research Institute (EPRI) under contract RP 2465-1 was performed to evaluate the comparative hot corrosion resistance of commercially available coatings for gas turbine blades and vanes. A 10,307-hr field test was carried out on a Solar Centaur T-4000 gas turbine operating on a lower grade liquid fuel at the Owens-Illinois, Inc. glass manufacturing facility in Valera, Venezuela. This paper reviews the results of an evaluation of the performance of a simple aluminide, a Pt, Rh-aluminide and two MCrAlY (M = Co, NiCo) overlays applied to the first stage FSX-414 vanes. As found for blade coatings, on the basis of visual and metallographic examination, and remnant coating thickness measurements, it was established that the MCrAlY coatings were generally more effective than the simple aluminide and the Pt, Rh-aluminide in providing protection to first stage vanes. A remnant coating thickness index (RCTT) was used to express coating survival and protectiveness quantitatively. The results of the study have been compared with literature.
Repair Standards for Aero and Industrial Turbine Blades
Authors: Liburdi J. , Lowden P.
Published: March 2015

The maintenance of aero and industrial engines requires components to be refurbished to a level appropriate to their service and overhaul requirements.

In some cases, the refurbishment of jet engine blades requires only minor tip restoration, whereas, in other cases, complete remanufacturing and heat treating are necessary.

This paper examines the various levels of repair performed on aero and industrial blades, as well as reviewing the influence of these repairs on the reliability and the remaining life of these parts.

It is essential that turbine operators recognize that repairs can vary, not only in extent, but in quality and reliability. Therefore, they must specify the appropriate standard of repair and re-certification required for their engines.
Distortion of Three-Dimensional Vorticity Waves by a Cascade of Airfoils
Authors: Fang J. , McHugh P. R. , Atassi H. M.
Published: March 2015

The evolution of three-dimensional vorticity waves impinging on a cascade of loaded blades in subsonic flow is studied. Analytical expressions are derived for the streamwise, normal and spanwise components of the vorticity and the associated rotational velocity. These unsteady flow quantities are calculated, and their variations analyzed and plotted for a typical loaded cascade. The results show that at large distances from the blades a slow but long range distortion of the incoming vorticity waves takes place. Near the blade surface, the stretching and turning of the vorticity produce large values for the streamwise vorticity component.
Experimental Study of a Reverse Flow Combustor: Influence of Primary Holes on Combustor Efficiency
Authors: Cadiou Anne , Grienche Guy
Published: March 2015

The primary zone of the reverse flow combustors for helicopters tested at ONERA is fed with air from primary holes, multiples holes for the wall cooling and prevaporiser tubes.

The effect of the primary holes on the combustor performances has been studied.

Gas sampling inside the combustor has been achieved in order to understand the flow mechanisms with and without primary holes. The differences observed on the 2 configurations are not significant. Air from the prevaporiser tubes and from the wall cooling is sufficient for the air feeding of the primary zone.
Development of a Dual Fuel Injector for a Gas Turbine Combustor
Authors: Schlein B. C. , Fox T. G. , Puma C. J.
Published: March 2015

A dual fuel nozzle has been developed for the FT-8, an industrial version of Pratt and Whitney’s JT8D engine. The nozzle is configured with a natural gas passage wrapped around a liquid air blast nozzle. The paper describes the development of the nozzle in a single can rig in a high pressure facility. A test program was conducted which parametrically varied the swirl angle of the air passage swirlers. Stability, smoke, and exit gas temperature profile data were acquired with Jet A, diesel and methane fuels and used to optimize the design. An optical probe was used to observe starting, blowout and transition from liquid to gaseous fuels and vice versa.
Overview of Gas Turbine Coal-Fired Combustor Concepts
Authors: Parsons Edward L. , Byam John W.
Published: March 2015

Since 1982, the Department of Energy (DOE), through the Morgantown Energy Technology Center (METC), has been conducting research for the purpose of verifying the feasibility of using coal fuels in heat engine applications. The heat engines of primary concern are the gas turbine and the diesel engine. The overall program objective is to develop the technology base for an environmentally sound, integrated heat engine system which will produce cost-competitive energy from coal. During the past 2 years the major emphasis of the gas turbine development program has been the coal-fueled combustors. This paper will review the current progress on coal-fueled gas turbine combustor development.
Dry Low NOx Combustion Development for Electric Utility Gas Turbine Applications: A Status Report
Authors: Angello Leonard , Lowe Phillip
Published: March 2015

National standards for NOx control for gas turbines are being evaluated and modified throughout the world. These standards are often supplemented by local or site specific emission limits. The numeric value of any emission limit is influenced by both the local environmental conditions, and, importantly, by the actual NOx removal capacity of the specific technologies that can be applied to the processes and equipment that will be governed by the emission standards. That is, emission limits can not be so restrictive that there is no technology available that can be applied to meet the permit condition. However, as new technologies are developed to meet the ever increasingly restrictive emission limitations, they become the standard by which the next round of emission limit setting is guided.

Current NOx control technologies for gas turbine applications employ fuel switching to a low nitrogen content fuel, wet combustion control (steam or water injection into the combustor), or exhaust gas treatment (selective catalytic reduction technology) or combinations of those controls.

Recently, dry combustion controls have been, or are being, developed by the gas turbine manufacturers, and catalytic combustion control processes are being researched. This paper presents a brief overview of the national NOx emission requirements of Europe, Japan, and the United States. A discussion of the new dry, low NOx controls presently emerging in the electric utility, gas turbine market are then reviewed, with an emphasis on the commercial applications and typical operating results that have been experienced.

In this paper, all NOx values are referenced to dry, 15% oxygen exhaust conditions unless otherwise stated. The units are volumetric, in parts per million (ppm), unless otherwise stated.
The Effects of Inerts on Emissions and Performance of an Industrial Engine
Authors: Rajput A. P. , Hurd P. J. , Wood R. D.
Published: March 2015

Gaseous fuels such as landfill gas contain significant quantities of inerts, typically CO2 and N2. This can lead to difficulties in predicting the emission and thermodynamic performance of industrial gas turbines. An algorithm has been developed to predict emissions of NOx for known quantities of inerts and effects on performance quantified. The effect of steam injection is compared to that of inerts and a relationship established.
Holographic Flow Visualisation of Turbofan By-Pass and Core Nozzle Streams
Authors: Bryanston-Cross P. J. , Harris A. E. , Bakshi S.
Published: March 2015

This investigation has been made to show the suitability of holography as an optical flow diagnostic for turbofan nozzle flow structures. In this case a static 1/25th scale model of a powered turbofan nacelle has been used for nacelle/wing integration studies and evaluated using a holographic technique.

The holograms made show the core jet and the by-pass flow as it emerges from the nacelle nozzle system. They also show evidence of structural vibration at the by-pass nozzle wall.

A comparison has also been made with alternative non-invasive diagnostic techniques.
Influence of Fuel Composition and Spray Characteristics on Nitric Oxide Formation
Authors: Rink K. K. , Lefebvre A. H.
Published: March 2015

Measurements of nitric oxide emissions are carried out on a continuous flow combustor when operating over wide ranges of fuel/air ratio at pressures up to 1.52 MPa (15 atmos). Fuel is supplied to the flame zone from a circular array of 30 equispaced miniature airblast atomizers which is incorporated into a perforated-plate flameholder. Standard instrumentation and sampling techniques are used to measure pollutant emissions over wide ranges of mean fuel drop size. The results obtained with several selected fuels demonstrate the effects of variations in fuel composition, fuel drop size, and combustor operating conditions on nitric oxide emissions.
Catalytic Combustor for Small Gas Turbines: Combustor Development
Authors: Kitajima J. , Kajita S.
Published: March 2015

As described previously in ASME papers, an effort has been underway to apply catalytic combustion for small gas turbines. To improve combustion efficiency at the engine operating conditions, two catalytic combustors have been developed. Both combustors showed high combustion efficiency and low NOx emissions in combustor rig tests. In engine tests, Type A combustor achieved the NOx goal of 15 ppmv as corrected to 5 percent oxygen (5.6 ppmv at 15 percent oxygen) for base load operation. Combustion efficiency was greater than 98 percent for the fresh catalyst, however, it decreased rapidly with catalyst deactivation.
The Effects of Hydrocarbon Fuels Upon Exhaust Pollutants in Gas Turbine Combustors
Authors: Kretschmer D. , Odgers J.
Published: March 2015

More than 100 different fuels have been examined for the influence of their properties on pollutant levels, using two different combustors. Comparison with data from other sources is attempted. Some simple correlations are suggested.
Tailoring Zirconia Coatings for Performance in a Marine Gas Turbine Environment
Authors: Strangman T. E. , Schienle J.
Published: March 2015

Zirconia coatings represent an advanced materials technology that offers significant durability and performance benefits for marine gas turbines. Thin zirconia coatings offer superior resistance to hot corrosion attack from fuel (sulfur, vanadium and sodium) and air (sea salt) impurities present in marine engine environments. Thicker zirconia coatings reduce transient thermal stresses and heat transferred into air-cooled components. This paper describes the development of zirconia coatings, applied by the electron beam evaporation - physical vapor deposition process, that are tailored to provide superior durability in a marine engine environment.
The Aerodynamics of an Oscillating Cascade in a Compressible Flow Field
Authors: Buffum Daniel H. , Fleeter Sanford
Published: March 2015

Fundamental experiments are performed in the NASA Lewis Research Center Transonic Oscillating Cascade Facility to investigate and quantify the aerodynamics of a cascade of biconvex airfoils executing torsion mode oscillations at realistic reduced frequency values. Both steady and unsteady airfoil surface pressures are measured at two inlet Mach numbers, 0.65 and 0.80, and two incidence angles, 0 and 7 degrees, with the harmonic torsional airfoil cascade oscillations at realistic high reduced frequency and unsteady data obtained at several interblade phase angle values. The time-variant pressures are analyzed by means of discrete Fourier transform techniques, with these unique data compared with predictions from a linearized unsteady cascade model. The experimental results indicate that the interblade phase angle has a major effect on the chordwise distributions of the airfoil surface unsteady pressure, with the effects of reduced frequency, incidence angle, and Mach number somewhat less significant.
Desktop Failure Analysis on a Microcomputer Using Weibull, Lognormal and Renewal Data
Authors: Byers J. L.
Published: March 2015

Gas turbine components and parts are widely known to have many failure modes for which the failures correlate in either the Weibull or Lognormal probability distributions. This paper describes a typical case which is handled by the new computer programs now being used by the U. S. Navy. These programs have brought the capability to make such analyses directly to the designer or analysts desk instead of having to be sent off to a central computer to wait in line. The programs are interactive with the user and extremely user friendly. Uses are expanding to cover almost every area in the life cycle of gas turbines where it would be beneficial to forecast future failures. This makes the programs useful to managers, logisticians, life cycle cost analysts, and a host of others. Wide applicability of the methods assures usage outside of the gas turbine field.
A Method of Sizing Multi-Cycle Engines for Hypersonic Aircraft
Authors: Kolden Jennifer J.
Published: March 2015

A method of sizing multi-cycle engines for integration with hypersonic vehicles has been developed. The new procedure independently sizes the inlet, each engine cycle, and the nozzle during the vehicle sizing loop to optimize propulsion/aircraft integration. Using uninstalled engine performance for each cycle of a multi-cycle engine along with inlet and nozzle performance and an estimate of aircraft drag, an iterative procedure is utilized to size each component simultaneously. A propulsion system is defined that meets the aircraft thrust requirements at all mission points. The inlet is sized to provide airflow such that the maximum Mach cruise and/or combat thrust conditions are met. Each cycle is sized independently to meet all thrust requirements while either minimizing inlet drag or engine size. Nozzle sizing must trade-off thrust, drag and nozzle weight. This methodology has been incorporated into a computer code entitled “Multi-Cycle Engine Sizing Program”, MCESP.