bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of the Radial Pressure Gradient on the Blade Root Loss in an Annular Subsonic Nozzle Cascade
Authors: Dai Meng , Zemin Weng , Yimin Xiang
Published: April 2015

This paper presents a method for predicting the blade root loss in an annular nozzle cascade in which the consideration is given to the influence of the radial pressure gradient (RPG) on it. The variation of blade root losses under different RPG is obtained experimentally and finite element method is used to calculate the pressure distribution in the blade passage.
Selection of the Most Advantageous Gas Turbine Air Filtration System: Comparative Study of Actual Operating Experience
Authors: Gilani Seyed I. , Mehr Musadaq Z.
Published: April 2015

This paper discusses relative merits of three types of air filtration systems used by Sui Northern Gas Pipelines Ltd. (Pakistan), on its gas turbine compressor packages. These Filtration systems are:

(i) Two stage inertial plus auto oil bath type multi-duty filters by AAF used on Saturn Mark–I packages manufactured by Solar Turbines Inc.

(ii) Three stage high efficiency barrier filters by AAF used on Centaur packages by Solar.

(iii) Single stage pulse-jet self-cleaning filter by Donaldson again used on a Centaur package.

The selection is primarily based on package performance data collected over a 15 month period analyzing power loss due to fouling effects and related operation and maintenance costs for the three systems.

The Company’s operating experience indicates that on new installations the pulse clean system offers the best advantage both in terms of filtration costs as well as availability of additional horse power when operating under moderate to severe environmental conditions.
A New Method for Predicting Performance of Axial-Flow Compressor
Authors: Yuan-Hu Cai , Hong-Ji Wang , Di-Yi Tang , Zhi-Wei Liu
Published: April 2015

A new method for predicting the off-design performance and the surge line of axial-flow compressors has been developed. In this method the stall points of stages are determined by generalized curves, which are derived from the criterion of rotating stall based on the neutral condition of stability, and the off-design characteristic of stages is calculated by a reasonable iterative method. The stage-stacking method is adopted to obtain the off-design performance of a multistage compressor. The surge line of the compressor is predicted with the “actuator-delay-volume” model and the method of numerical integration. Two examples are given. The results are satisfactory.
The Investigation of the Stability for Multistage Axial Compressors
Authors: Tang Diyi , Li Wenlan , Cong Mengzi
Published: April 2015

The “actuator-delay-volume” is used as a physical model for stages of compressors instead of “actuator-lumped volume” model to predict the stability of multistage compressors. The stall line of a multistage compressor is predicted with these two models respectively. The results of simulation are compared with the experimental data of a compressor rig. In order to identify the investigation, the tests, in which the engine is forced into stall and supplied with distorted inflow, have been conducted. The investigation shows that the model is well improved by incorporating an “inertia link” into the model between the “actuator” and the “lumped volume”.
On the Thermodynamic Properties of Combustion Gases
Authors: Jialu Yan , Ming Liu , Yushun Yang
Published: April 2015

In this paper, a linear correction method of deviation function and an interpolation method have been proposed to consider the real gas effect of combustion gases and the variety of hydrocarbon fuel. And, the thermodynamic properties of combustion gases in dissociated states are calculated to 4000K on the basis of chemical equilibrium theory. The whole work has resulted in compiling a new combustion gas table.
Comparison of Algorithms for Two-Dimensional Mechanical Performances of Squeeze Film Damper
Authors: Xinmin Shen , Yingmei Wen
Published: April 2015

The object of this paper is to explore some effective algorithms for two-dimensional mechanical performance of squeeze film damper used on gas turbines. A number of modern algorithms have been compared through detailed analyses and calulations. In the result, two effective algorithms with the solution of two-dimensional Reynolds equation and relative dimensionless data are presented together with a method for system analysis using dimensionless data storage and parabolic interpolation. The methods are more accurate and time-saving.
The Transonic Flow Through a Plane Turbine Cascade as Measured in Four European Wind Tunnels
Authors: Kiock R. , Lehthaus F. , Baines N. C. , Sieverding C. H.
Published: April 2015

Reliable cascade data are essential to the development of highspeed turbomachinery, but it has long been suspected that the tunnel environment influences the test results. This has now been investigated by testing one plane gas turbine rotor blade section in four European wind tunnels of different test sections and instrumentation. The Reynolds number of the transonic flow tests was Re2 = 8 · 105 based on exit flow conditions. The turbulence was not increased artificially. A comparison of results from blade pressure distributions and wake traverse measurements reveals the order of magnitude of tunnel effects.
Method of Spare Parts: Digital Simulation of Aircraft Turbine Engine Control System
Authors: Yan-Shen Guan , Juhng-Sheng Warng , Tzu-Cheng Lee
Published: April 2015

The paper presents a new method of digital simulation of a control system. A computer program of an aircraft engine control system, as for an example, is implemented as a full authority digital simulator. The results of simulation show that the functions and applications of the simulator are extended as compared with those of the other type mathematical simulators.
The Production of Jet Fuel From Alternate Sources
Authors: Lander Herbert R. , Reif Henry E.
Published: April 2015

The most significant potential source of aviation gas turbine fuels in the continental United States of America is the western oil shale located in the Rocky Mountain States of Colorado, Utah, and Wyoming. Nearly 600 billion barrels of recoverable oil is located in this area. This paper discusses the availability of oil shale and reviews the recovery, upgrading and refining schemes necessary to produce fuel which can be used in present-day aircraft.

Other synthetic fuels are discussed with regard to the processing necessary to produce suitable fuels for today’s high performance aircraft. Heavy oil and tar sand bitumen are likely to be refined in the next decade. Methods for producing suitable fuels are discussed. The chemical structure of these sources, which is basically cyclic, leads to the potential of heavier fuels with more energy per given volume and therefore longer range for certain aircraft. This exciting possibility is reviewed.
Gyroscopic Mode Synthesis in the Dynamic Analysis of a Multi-Shaft Rotor-Bearing System
Authors: Zhao-Chang Zheng , Xiao-Ping Zhou , De-Bao Li , Lian-Xiang Zhang , Ting-Yi Liu , Cheng-Xi Yue
Published: April 2015

A mode synthesis method used in the dynamic analysis of multi-shaft rotor-bearing system has been developed in this paper. By introducing the idea of connecting springs and dampers, and using gyroscopic modes instead of complex modes in the mode synthesis, this method differs not only from classical component mode synthesis method, but also from complex mode synthesis. Several numerical examples show the advantages of this method.
Application of Vortex Generators in Flow Control of the Inlet
Authors: Xiao Chen , Liang-Wei Fang
Published: April 2015

This paper introduces the features of using co-rotating vortex generators for controlling boundary layer and flow field in the inlet without flow separation. The principles of the arrangements of the blades and selection of constructional parameters of the generators that are applied to create the transverse flow between the high and low pressure regions and to reduce the secondary flow losses are analysed. The experimental results show that when the appropriate parameters of the co-rotating vortex generators are chosen for the inlet subsonic diffuser with apparent high and low pressure regions, not only the nonuniformity of the flow field is greatly improved but also the dynamic performance of the flow at exit is slightly improved.
Influence of Aluminide Coating on Fatigue Behavior of a Nickel Superalloy
Authors: Jianping Xu , Jiyuan Xiong
Published: April 2015

The influence of the technology and the thickness of an aluminide coating on mechanical fatigue of a nickel-alloy at 700°C has been studied. It was shown that the brittleness and the surface roughness of coating were the basic causes to the earlier rupture of a system. The thicker coating, the more harmful to fatigue performance. The mechanism of influnece of coating on metal fatigue and the possibility to estimate fatigue life of coating/alloy system were also discussed. It is believed that the stress concentration caused by coating crack accelerated substrate alloy to rupture.
Propagation of Steady Circumferential Distortion Through an Axial Compressor Rotor
Authors: Min Zhang Hui , Jun Hu
Published: April 2015

In this paper, a time marching method is proposed to predict the propagation of steady inlet circumferential distortion through an axial flow compressor rotor (or stator). This method also adopt the “Semi-actuator disk” concept to replace the rotor. It is assumed that the flow fields outside of the disk are described by a set of ideal, compressible and unsteady quasi-linear partial differential flow equations. Furthermore, the unsteady response of rotor is also taken into account. This method can be easily developed to a stage or extended to investigate the effect of transient disturbance on the stability of a compressor. Through numerical experiments, it has been found that distortion amplitude, rotation of the rotor, the chord length and especially the characteristic curves of the blade row have crucial effect on the attenuation behavior of the rotor.
Digital Simulation of Thermal Turbomachinery Systems
Authors: Wei-Dou Ni , Xian-Dong Xu
Published: April 2015

A flexible modular type calculation method is developed in this paper, it can be used to a multitude of applications, thus permitting many required turbomachinery systems to be simulated. In this method every standard component is considered as a subsystem, which can be readily linked in diverse ways with other components. This method can also be used for calculating the transients of nonlinear systems under large pertubation. As a case study, a computer programme for simulating the energy recovery system of the fluidized catalytic cracking (FCC) installation is presented.
The Development of a Second-Generation of Controlled Diffusion Airfoils for Multistage Compressors
Authors: Behlke R. F.
Published: April 2015

The evolution of Controlled Diffusion Airfoils is traced from inception of the theoretical design model to demonstration of significant performance gains at engine operating conditions in a multistage compressor rig. The proven aerodynamic benefits and versatility of first-generation Controlled Diffusion Airfoil blade elements are extended to the endwall flow region using an Integrated Core/Endwall Vortex design model to produce a new full span optimized second-generation Controlled Diffusion design. Highlighted are the essential roles of extensive cascade, low speed, large scale and high Mach number compressor rig testing in developing and substantiating the second generation Controlled Diffusion technology resulting in a 1.5% increase in efficiency and 30% increase in surge-free operation relative to first-generation Controlled Diffusion Airfoils.
The Analysis of Crack Propagation Law at Slot Bottom in Turbine Disk
Authors: Jingxu Nie , Qilin Hong
Published: April 2015

During the operation of the gas turbine engine, the crack initiation sites have frequently been found at the slot bottom in turbine disks. Taking the cracks at above mentioned position of the existing turbine disk as an example and considering the feature that the cracks usually initiate early and grow slowly, this paper searches for the initiative cause and the propagation law of such cracks. The results obtained can be employed as an important basis for damage tolerance or fracture control for engine design.
Experimental Investigation of Tandem Blade Cascades With Double-Circular ARC Profiles
Authors: Guochuan Wu , Biaonan Zhuang , Bingheng Guo
Published: April 2015

24 double circular are tandem blade cascades of three different chord-ratios were investigated under different displacements in peripheral and axial direction. The inlet Mach number was 0.3. The Reynolds number based on blade chord was 2.7×105. The characteristics of the tandem blade cascades, such as the dependence of turning angle and coefficient of total pressure loss on incidence angle were obtained. The ranges of main geometrical parameters under optimal conditions were recommended.
Gas Turbine Compressor Unit Application in Sour Gas Field Operation
Authors: Schmidt Klaus D. , Scholz Werner , Schlüter Hartmut
Published: April 2015

The use of sour gas as primary energy requires constant supply pressure and flow to the gas treatment plant as well as to the pipeline distribution network and consumers.

During exploitation of gas fields, when the well head pressure and flow decreases, production continues at increased cost.

Application of gas compression equipment is required for continuation of supply pressure and flow to the sour gas treatment plant and to customer connection flanges.

The design and layout of sour gas compression equipment has to guarantee high operational availability and reliability for continuous duty.

To properly select equipment for sour gas applications, including the compressor, its driver and auxiliary and ancillary systems, the specific requirements and standards have to be taken into consideration.

This paper will report about a situation in the sour gas fields in the northern part of West Germany and will describe the design objectives, station layout and equipment selection for a sour gas compressor station including operating experiences.
A Frictionally Induced Bladed Disk/Shaft Instability: Physical Explanation of an Experimental Fan Failure
Authors: Klompas N.
Published: April 2015

A light weight fan with a novel tip damper, designed and rig tested in the sixties, sustained a cataclysmic vibratory failure during a test with consistently smooth running and an explanatory dynamic mechanism was not found. It is now shown that instability potentially could have been induced in a synchronous backward wave by phase shift due to difference between kinetic and static friction in the damper. Moreover, the same mechanism could have augmented the steady forward harmonic wave recorded by Campbell in the twenties.
Row Resolved Heat Transfer Variations in Pin-Fin Arrays Including Effects of Non-Uniform Arrays and Flow Convergence
Authors: Metzger D. E. , Shepard W. B. , Haley S. W.
Published: April 2015

Measured streamwise (longitudinal) heat transfer variations, spanwise (transverse) averaged and resolved to single row spacings, are presented for large aspect ratio ducts containing staggered arrays of circular pin fins which span the entire duct height. A number of different array geometries have been investigated in an experimental program, including uniformly spaced arrays in constant cross sectional area ducts with streamwise row spacings over the range 1.5 to 5.0 pin diameters. Such arrays, with pin length-to-diameter ratio of order unity, are often used to enhance heat transfer in internal cooling passages of gas turbine engine airfoils. The effects of various length interruptions in the pin pattern and of abrapt changes in pin diameter are presented for constant cross sectional area ducts. In addition, results are presented for the effect of duct convergence, a common situation in the cooled turbine airfoil application. A concise summary of all the observed behavior is given, useful for predicting the performance of arbitrarily spaced pin fin arrays that may be specified to produce a particular cooling distribution. Predictions are compared with two final test, configurations which combine aspects of all of the effects investigated in the experimental program.
Rotating Heat Transfer Experiments With Turbine Airfoil Internal Flow Passages
Authors: Wagner Joel H. , Kim Jay C. , Johnson Bruce V.
Published: April 2015

Internal convective cooling is used to maintain acceptable gas turbine rotor blade temperatures. The heat transfer from the blade coolant passage walls is governed by forced convection, Coriolis forces and buoyance due to wall and coolant temperature differences. Currently little data is available to designers regarding the combined effects of these three parameters. To obtain required data, a rotating heat transfer facility was developed for experiments with large scale models and run at rotation and flow parameters typical of current gas turbine operating conditions. Analysis of the equations of motion showed that the perinent nondimensional parameters were Reynolds number, Rossby number, the difference in wall fluid and bulk fluid density and geometric ratios. The models were instrumented to measure average heat transfer rates on the coolant passage wall elements, and with pressure taps for friction data. An initial set of experiments have been conducted with rough wall geometries, typical of those used in blades. Results from the rotating experiments showed large heat transfer coefficient increases and decreases on the coolant passage leading and trailing surfaces compared to nonrotating heat transfer coefficients. The heat transfer was shown to be a function of inward or outward flow direction and Rossby number for the experiments conducted.
Experimental Investigations of Airfoil- and Endwall Boundary Layers in a Subsonic Compressor Stage
Authors: Gallus H. E. , Hoenen H.
Published: April 2015

Criteria for the maximum diffusion allowable in a blade row without reaching stall play an important part in the design of highly loaded axial-flow compressors. Most of these criteria for maximum blade loading were derived from wind tunnel measurements of 2-d-steady cascade flow. As the flow field in turbomachines is extremely unsteady and of three-dimensional nature the boundary layers are influenced by these effects.

The paper deals with the results of boundary layer measurements in a stator blade channel of a subsonic axial-flow compressor stage at various operating points between unthrottled and highly throttled flow (near stall). In front of the stator, the time-averaged velocity profiles as well as the fluctuations due to the unsteady flow field downstream of the rotor were measured. The growing of the separation zones inside the channel with increased blade load is studied in detail. Photos of flow visualization in the boundary layers by dye-injection and flow patterns derived from hot-wire measurements illustrate the physics of boundary layer behavior and separation due to increasing stator blade load. The investigations include measurements of the turbulence energy and a frequency analysis of the velocity fluctuations in the boundary layers.
The Use of a Distributed Body Force to Simulate Viscous Effects in 3D Flow Calculations
Authors: Denton J. D.
Published: April 2015

Three dimensional viscous flow calculations methods for turbomachinery are starting to become available but are not yet sufficiently well developed to be used for design purposes. Three dimensional inviscid calculations on the other hand are now well developed and are widely used for design purposes. This paper describes a method intermediate between fully viscous methods and inviscid methods. The viscous effects are approximated by a very simple model which can be tuned empirically to get the correct overall level of loss and which reproduces many of the details of real viscous flow, such as boundary layers and secondary flows. The method is a simple extension to a widely used inviscid method and enables viscous effects to be simulated with little extra computational cost compared to a 3D inviscid calculation.
A Numerical Method for the Analysis of 3D Viscous Compressible Flow in Turbine Cascades: Application to Secondary Flow Development in a Cascade With and Without Dihedral
Authors: Dawes W. N.
Published: April 2015

The present paper describes a computer code, currently under development, aimed at solving the equations of three-dimensional viscous compressible flow in turbomachinery goemetries. The code uses a simple, novel pre-processed implicit algorithm. An outline of the method is given and the current capabilities of the code are assessed.

The code is applied to the study of the flowfield in a cascade of transonic gas turbine rotor blades. The geometry and the presence of inlet end-wall boundary layers lead to significant three-dimensional effects. The pattern of secondary flow development, including the details of the leading edge horseshoe vortex and associated saddle point, are clearly resolved and correspond to experimental experience. A computation is also presented to show the influence of dihedral (non-linear stacking) on the secondary flow development.
Conical Grid Plate Flame Stabilizers: Stability and Emissions for Liquid Fuels
Authors: Ali A. F. , Andrews G. E.
Published: April 2015

Flame Stability and Emission results are presented for a jet shear layer primary zone design consisting of a 90° conical flame stabiliser with a central annular vaporiser fuel injection system feeding an array of air jets. The performance with kerosene and gas oil fuels is compared with previous work with propane. The influence of the primary zone residence time or Mach number is shown to be much more significant for liquid fuels than for propane. An acceptable combustion efficiency was only achieved at a Mach number of 0.03, corresponding to 60% of the combustion air in the primary zone, provided that the pressure loss was maintained as the Mach number was reduced by using a stabiliser of higher blockage. NOx emissions with kerosene were compatible with those for propane, but for gas oil there was a significant increase in NOx.
Unsteady Flow Calculation in Cascades
Authors: Fourmaux Antoine
Published: April 2015

This paper describes a two dimensional unsteady calculation method which applies to the flow computation in two blade-rows having different angular speeds.

The Euler equations are solved using the classical predictor-corrector McCormack scheme. The program can be used in many cases involving time-dependent phenomena : mutual influence of two blade-rows, distortion problems, wake passage effects, aeroelasticity.

First, the computation program is described with a special importance being given to the boundary-conditions. Then, two calculation examples are given which allow one to evaluate the potential of this method for a detailed unsteady flow analysis.
Three-Dimensional Boundary Layer on a Compressor Rotor Blade at Peak Pressure Rise Coefficient
Authors: Lakshminarayana B. , Popovski P.
Published: April 2015

A comprehensive study of the three-dimensional turbulent boundary layer on a compressor rotor blade at peak pressure rise coefficient is reported in this paper. The measurements were carried out at various chordwise and radial locations on a compressor rotor blade using a rotating miniature “V” configuration hot-wire probe. The data are compared with the measurement at the design condition. Substantial changes in the blade boundary layer characteristics are observed, especially in the outer sixteen percent of the blade span. The increased chordwise pressure gradient and the leakage flow at the peak pressure coefficient have a cumulative effect in increasing the boundary layer growth on the suction surface. The leakage flow has a beneficial effect on the pressure surface. The momentum and boundary layer thicknesses increase substantially from those at the design condition, especially near the outer radii of the suction surface.
A Method for Transonic Inverse Cascade Design With a Stream Function Equation
Authors: Manchu Ge , Yiping Lou , Zhengti Yu
Published: April 2015

A new profile design method is developed on the basis of Refs.1–3 for transonic flow. The rotational dynamic stream function equation, which is expressed in functional form of calculated coordinates, is deduced. This method can be used for the calculation of cascade and S1 stream surface of a transonic flow with local shock wave on the blade suction surface. This method consists of two parts. One is a inverse method with a given velocity distribution along the suction surface and a given thickness distribution. Another is a inverse method with given velocity distributions on suction and pressure surfaces. Using this method it is easy to get the blade profile with prescribed velocity and thickness distributions. The design of optimal profile may then be done with the calculated optimal velocity distribution on the blade surface. The rotational condition is satisfied when the stream function equation is adopted with the entropy term. If the compatibility condition can be fulfilled between the S1 and S2 equations. The iterative calculations of two kinds of stream surfaces of 3-D flow will be convergent. In this paper a unique value of density can be determined from the known stream function value. The computational programme is written with this method and several transonic examples have been calculated. These results are quite good.
The Segregated Approach to Predicting Viscous Compressible Fluid Flows
Authors: van Doormaal J. P. , Raithby G. D. , McDonald B. H.
Published: April 2015

The SIMPLE method of Patankar and Spalding and its variants such as SIMPLER, SIMPLEC and SIMPLEX are segregated methods for solving the discrete algebraic equations representing the equations of motion for an incompressible fluid flow. The present paper presents the extension of these methods to the solution of compressible fluid flows within the context of a generalized segregated approach. To provide a framework for better understanding the segregated approach to solving viscous compressible fluid flows an interpretation of the role of pressure in the numerical method is presented. With this interpretation it becomes evident that the linearization of the equation for mass conservation and the approach used to solve the linearized algebraic equations representing the equations of motion are important in determining the performance of the numerical method. The relative performance of the various segregated methods are compared for several subsonic and supersonic compressible fluid flows.
Stator Endwall Leading-Edge Sweep and Hub Shroud Influence on Compressor Performance
Authors: Tweedt D. L. , Okiishi T. H. , Hathaway M. D.
Published: April 2015

The use of stator endwall leading-edge sweep to improve axial-flow compressor stator row performance was examined experimentally. The aerodynamics of three stator hub (inner diameter) conditions, namely, a running clearance, a stationary clearance, and a shroud were also investigated. Leading-edge sweep in the endwall regions of a stator blade can be beneficial in terms of loss reduction on the casing (outer diameter) end of a stator blade. It can also help at the hub end of a stator blade when either a stationary hub clearance or a hub shroud is used. A leading-edge sweep is detrimental (local loss increase) on the hub end of a stator blade when a running hub clearance is used. A running clearance is aerodynamically preferable to a stationary clearance.
Structural Analysis and Life Prediction for Ceramic Gas Turbine Components for the Mercedes-Benz Research Car 2000
Authors: Hempel H. , Wiest H.
Published: April 2015

The paper considers the design and the application of ceramic components in a high temperature gas turbine, which is being developed as an alternative for passenger-car propulsion. Silicon nitride turbine wheels were analyzed using 3-dimensional finite element methods.

Calculations of temperatures and stresses were carried out for several steady-state and transient load conditions. Time dependent reliability was also computed using the theory of Weibull including subcritical crack growth.

The results of these calculations are presented and discussed. The basic theory for ceramic life prediction methodology is reviewed, including the relative importance of various parameters. From the results, conclusions are derived for ceramic design. Finally some operating-experiences of ceramic turbine wheels are reported.
Power Turbine Vane Ring (PT6 Engine) Repair Development
Authors: Sourial N.
Published: April 2015

Today’s high technology gas turbine engines incorporate the world’s most exotic alloys and are built to some of the most precise dimensional tolerances encountered in any industry.

The constant drive for increased performance while substantially reducing fuel consumption and weight has pushed engine components and their designers to limits never before realized. To achieve these limits new methods and materials have evolved; not exclusively in the production of the engines but also in the repair and maintenance of them.

The typical problems encountered in repair and maintenance are numerous and varied as are their solutions. This paper, however, will concentrate on one in particular and that is the typical damage encountered on a first stage power turbine vane ring and the technology employed to repair such damage.

The vane ring was chosen because it is representative of a common problem encountered by all gas turbine engine manufacturers and simultaneously involves some of the most up to date repair techniques to restore it.
An Accurate and Efficient Euler Solver for Three-Dimensional Turbomachinery Flows
Authors: Shieh C. F. , Delaney R. A.
Published: April 2015

Accurate and efficient Euler equation numerical solution techniques are presented for analysis of three-dimensional turbomachinery flows. These techniques include an efficient explicit hopscotch numerical scheme for solution of the 3-D time-dependent Euler equations and an O-type body-conforming grid system. The hopscotch scheme is applied to the conservative form of the Euler equations written in general curvilinear coordinates. The grid is constructed by stacking from hub to shroud 2-D O-type grids on equally spaced surfaces of revolution. Numerical solution results for two turbine cascades are presented and compared with experimental data to demonstrate the accuracy of the analysis method.
Acceptance Criteria for Heat Recovery Steam Generators Behind Gas Turbines
Authors: Pasha Akber
Published: April 2015

The design of a Heat Recovery Steam Generator behind a gas turbine depends upon various input parameters such as gas turbine exhaust flow, exhaust temperature, etc. Most of the input parameters are either measured with tolerances or calculated based on experimental correlations. The design of the heat recovery steam generator itself utilizes various correlations and empirical values. The errors or measurement tolerances in these variables affect the performance of the steam generator.

This paper describes the various design parameters, the possible magnitude of errors in these parameters and the overall effect on the steam generator’s performance.

By utilizing the information given in this paper, it is possible to develop a performance envelope based on the possible error margins of the input variables. The steam generator performance can be deemed acceptable if it is within this envelope.
Intercooled/Recuperated Shipboard Generator Drive Engine
Authors: Mills R. G. , Karstensen K. W.
Published: April 2015

Adverse consequences of losing electrical power to complex electronic and fire control equipment, or of the sudden variations of shore power, cause naval combatants to operate two generators most of the time, each at light load where specific fuel consumption of simple-cycle gas turbines is particularly high. The recuperated gas turbine with variable power-turbine nozzles has a much better specific fuel consumption, especially at part load. Herein described is a compact recuperated gas turbine with variable power-turbine nozzles designed for marine and industrial use, suitable with or without intercooling. These features yield a specific fuel consumption that is comparable to marine diesels used for generator drive, and essentially flat across the entire usable load range.
Gas Turbine Transient Fuel Scheduling With Compensation for Thermal Effects
Authors: MacCallum N. R. L. , Pilidis P.
Published: April 2015

Most current fuel schedules for accelerating or decelerating gas turbines use a limiting non-dimensional fuel flow expressed as a function of some engine parameter such as compressor pressure ratio. Usually the same schedule is used for, for example, accelerating ‘cold’ and ‘hot’ engines. This results in differing acceleration rates and differing usage of surge margins. The paper describes two methods of compensating the fuel schedules to account for the engine’s immediately preceding temperature history. One method uses the temperature response of the aerofoil of blades in the H.P. Compressor. The second method, which appears to be an improvement, uses a ‘delayed’ H.P. Shaft speed signal.
Mechanical Reliability Operational Experience in the Modern High Temperature Industrial Gas Turbine
Authors: Korta J.
Published: April 2015

The CW352 two shaft industrial type gas turbine was first put in commercial service in 1979. By mid 1985 units in simple cycle and regenerative modes have accumulated in excess of 200,000 hrs. of operation, with lead units in excess of 50,000 hrs. simple cycle mode and 35,000 hrs. in regenerative cycle mode. The paper discusses the operational experience with emphasis on early field problems and their solutions.
Analysis of Impeller Vibration in Radial Compressors
Authors: Wachter J.
Published: April 2015

The prediction of the dynamic behaviour of the impellers is of considerable importance in the design of turbomachines. The excitation possibilities of the radial impellers by the forces or imposed displacements are various and an appreciation of the life of radial impellers is strongly bounded to an accurate dynamic analysis. Therefore, it is necessary to analyze them in order to improve the geometry or modify the design. In order to better understand and explain the dynamic behaviour of impellers, a series of impeller models with various numbers of blades of radial or tangential extention have been examined. Because of complexity of analytical analysis shown in earlier works, the eigenfrequencies and modes of the impellers were evaluated using a Finite Element program. Interferometric holography served as a means to visualize the dynamic behaviour of the impellers. An experimental modal analysis was used to identify the modal parameters. A detailed application of these methods to an actual centrifugal impeller was also reported along with theoretical and experimental investigations on the impeller models.
Optimization of Industrial Centrifugal Compressors: Part 6A — Studies in Component Performance — Eight Design Cases From 1972 to 1982
Authors: Japikse David , Osborne Colin
Published: April 2015

The design optimization procedures, used over a period of ten years for a series of compressor designs, are reviewed. Overall performance and test procedures are detailed in Part 6A. The results of detailed interstage measurements are presented and discussed in Part 6B. The critical role of the laboratory in successful product development is illustrated (6B). Manufacturing procedures (castings vs. machining, thick leading edges, rough surfaces, etc.) are shown to significantly influence performance.
The “Axi-Fuge”—A Novel Compressor
Authors: Wiggins Jesse O.
Published: April 2015

Modifying a simple-cycle gas turbine to include heat exchangers can improve its thermal efficiency significantly (as much as 20%). Advanced regenerative and intercooled regenerative gas turbines for marine application have recently been the subjects of numerous studies, most of which have shown that lower fuel comsumption can be achieved by adding heat exchangers to existing simple-cycle gas turbines. Additional improvements in thermal efficiency are available by increasing the efficiency of the turbomachinery itself, particularly that of the gas turbine’s air compressor. Studies by Caterpillar Tractor Company and Solar Turbines Incorporated on a recuperated, variable-geometry gas turbine indicate an additional 8 to 10% improvement in thermal efficiency is possible when an improved higher efficiency compressor is included in the gas turbine modification. During these studies a novel (Axi-Fuge) compressor was devised. This paper discusses the Axi-Fuge concept, its origin, design criteria and approach, and some test results.
Navier-Stokes Solutions of Unsteady Flow in a Compressor Rotor
Authors: Scott James N. , Hankey Wilbur L.
Published: April 2015

In order to achieve more accurate predictions of unsteady flow in a transonic compressor rotor an existing numerical approach has been modified by incorporating a turbulence model. The computations are performed by solving the complete time-dependent compressible Navier-Stokes equations using MacCormack’s explicit finite difference algorithm. These equations are solved for the flow through two adjacent rotor blades at a stream surface near the blade tip subjected to the wakes emitted from upstream stators. At this radial location the flow enters the blade passage at an absolute Mach number of 0.66. The high blade curvature at this radial location produces a large region of separated flow on the suction surface with laminar flow. To more accurately resolve the features of this flow separation the Baldwin-Lomax algebraic eddy-viscosity turbulence model is incorporated into the numerical procedure in regions, near the blade surface. The unsteady flow features are represented at the inflow boundary through the use of characteristic variables involving the upstream and downstream running Riemann invariants and the entropy variation expressed in terms of the total pressure profile. At the outflow boundary the concept of a “second throat” or choke point is implemented in conjunction with supersonic outflow conditions. The results are compared with numerical results obtained without the use of a turbulence model (laminar) for a single blade passage. Improved agreement with limited experimental data is also noted.
Predictions of Endwall Losses and Secondary Flows in Axial Flow Turbine Cascades
Authors: Sharma O. P. , Butler T. L.
Published: April 2015

The development of a semi-empirical model for estimating endwall losses is described in this paper. The model has been developed from improved understanding of complex endwall secondary flows, acquired through review of flow visualization and pressure loss data for axial flow turbomachine cascades. The flow visualization data together with detailed measurements of viscous flow development through cascades have permitted more realistic interpretation of the classical secondary flow theories for axial turbomachine cascades. The re-interpreted secondary flow theories together with integral boundary layer concepts are used to formulate a calculation procedure for predicting losses due to the endwall secondary flows. The proposed model is evaluated against data from published literature and improved agreement between the data and predictions is demonstrated.
Construction and Operation of Gas-Steam Combined Cycle Plant for Higashi Niigata Thermal Power Station No. 3
Authors: Sudo Y. , Sato M. , Kobayashi Y.
Published: April 2015

This paper describes the construction and operation of the 1,090MW gas-steam combined cycle power plant, one of the largest of its kind in the world.

The plant consists of two trains, each of which combines three sets of gas turbines and heat recovery steam generators with one set of steam turbines. A gas turbine burns gasified LNG as fuel with gas firing temperature of 1,154°C at the base load operation, the highest temperature now in service, with a newly developed low NOx premixing type combustor system and generates 133MW each at maximum.

The construction of the plant was started in March, 1982 and the first train, namely, one half of 1,090MW has been in commercial operation since December, 1984 with a very high average thermal efficiency of 44.1% (H.H.V.). The 1,090MW total plant is scheduled to complete in October, 1985 when the second train starts commercial operation.
Multistage Turbine Erosion
Authors: Mengütürk Muhsin , Güneş Doğan , Erten Mustafa , Sverdrup Edward F.
Published: April 2015

This paper presents a computer package developed to calculate erosion damage in multistage turbines that operate with particle-laden gases. Erosion predictions based on calculated trajectories of particles are made either by using semiempirical erosion formula or through direct interpolation of existing experimental data. Also presented is an application of this package to a four-stage turbine that shows that the first and second stage rotor blades and the second stage stator blades may be subject to critical erosion damage.
Horseshoe Vortex Formation Around a Cylinder
Authors: Eckerle W. A. , Langston L. S.
Published: April 2015

An experimental investigation was conducted to characterize a symmetrical horseshoe vortex system in front of and around a single large-diameter right cylinder centered between the sidewalls of a wind tunnel. Surface flow visualization and surface static pressure measurements as well as extensive mean velocity and pressure measurements in and around the vortex system were acquired. The results lend new insight into the formation and development of the vortex system. Contrary to what has been assumed previously, a strong vortex was not identified in the streamwise plane of symmetry, but started a significant angular distance away from it. Rather than the multiple vortex sytems reported by others, only a single primary vortex and saddle point were found. The scale of the separation process at the saddle point was much smaller than the scale of the approaching boundary layer thickness. Results of the present study not only shed light on such phenomena as the nonsymmetrical endwall flow in axial turbomachinery but can also be used as a test case for three-dimensional computational fluid mechanics computer codes.
Quality Assurance in Manufacturing High Performance Ceramics
Authors: Srinivasan M. , Earl M.
Published: April 2015

Quality assurance of ceramic components during various processing stages is an important ingredient in assuring the reliability in engineering applications. The current advances which are made in advanced nondestructive evaluation of finished components have been very useful. However, the importance of in-process quality control in closed loop interative process and product development has to be understood in terms of materials science aspects. This paper addresses some of the tools in nondestructive evaluation which are available in ceramic manufacture and gives illustrations of successful implementation of those techniques in two catagories of ceramic applications, current and advanced. Further research and development needs in N.D.E. area also briefly addressed.
John Deere Score™ Engines in Marine Applications
Authors: Silvestri William B. , Wright Edward S.
Published: April 2015

The paper gives a basic description of the stratified charge combustion process in the Stratified Charge Omnivorous Rotary Engine - SCORE. The inherent advantages of the Wankel geometry combined with spark ignition of a stratified mixture for a unique combustion cycle are explained with diagrams. The discussion points out why the engine is neither octane or cetane sensitive, making it a truly multifuel (omnivorous) intermittent combustion engine.

A brief description of the parts and their function help to explain the inherent compactness of the engine and confirm its simplicity and efficiency. The engine specific size, weight, air flow and fuel flow are compared to an equivalent output turbine engine to place the performance in a familiar context.

A most impressive feature of the engine, attractive cost of production, is demonstrated by the modular nature of its design. This feature is amplified by an in-depth description of the “Family of Engines” concept, highlighting the large number of common parts in a family of one to six rotor models. The ability to cover a complete market segment with one geometry is attractive for production costs, service, training and logistics.

Modular design also enhances application flexibility. Development programs are underway for a diversity of applications for families of SCORE engines. Each application utilizes the unique characteristics available with this engine and is further justified by the economies realized in volume production. Thus low volume, high power applications (1000kW and up) can realize savings by utilizing the same major parts tooled for higher volume use in smaller engines.

Some potential applications are discussed with particular emphasis on marine installations. Specific comparisons with other powerplants for shipboard electrical generation are presented.
Life Assessment Technology for Combustion Turbine Blades
Authors: Viswanathan R. , Dolbec A. C.
Published: April 2015

Combustion turbine blades operating in the hot gas path are subject to degradation by embrittlement, creep, thermal fatigue, hot corrosion and synergistic effects among the above. Development of techniques to assess the extent of degradation of the blades under these conditions can have a significant and favorable economic impact for the utility industry. The Electric Power Research Institute (EPRI) is currently engaged in a number of research activities aimed at the development of such techniques. This paper is an overview of the present and planned activities relating to life assessment technology for blades.
Design and Testing of an Ultra-Low NOx Gas Turbine Combustor
Authors: Smith Kenneth O. , Angello Leonard C. , Kurzynske F. Richard
Published: April 2015

The design and initial rig testing of an ultra-low NOx gas turbine combustor primary zone are described. A lean premixed, swirl-stabilized combustor was evaluated over a range of pressures up to 10.7 × 105 Pa (10.6 atm) using natural gas. The program goal of reducing NOx emissions to 10 ppm (at 15% O2) with coincident low CO emissions was achieved at all combustor pressure levels. Appropriate combustor loading for ultra-low NOx operation was determined through emissions sampling within the primary zone. The work described represents a first step in developing an advanced gas turbine combustion system that can yield ultra-low NOx levels without the need for water injection and selective catalytic reduction.
10,000 Hours of LM2500 Gas Turbine Experience as Seen Through the Borescope
Authors: Siemietkowski John S. , Williams Walter S.
Published: April 2015

The General Electric LM2500 Marine Gas Turbine, currently used by the United States Navy as main propulsion on various classes of ships, lends itself very easily to a procedure known as photoborescopy. Photoborescopy is that process where discrete, color photographs are taken of various internal parts of the engine. Borescoping in itself is not new, but maximizing the borescopes capabilities is a program that the U.S. Navy continuously is developing at the Naval Ship Systems Engineering Station (NAVSSES) in Philadelphia, Pennsylvania.

This paper will describe the photoborescopy technique used by NAVSSES and also give and show graphically the Fleet experience with two LM2500’s which had accumulated 10,000 hours of successful at-sea operation.

The opinions expressed herein are those of the author and not necessarily of the Department of Defense or the Navy Department.