bluuebunny/crossref_metadata_2025 huggingface dataset:
The Design and Testing of a Radial Flow Turbine for Aerodynamic Research
Authors: Huntsman I. , Hodson H. P. , Hill S. H.
Published: March 2015

This paper describes the design of a high-speed radial inflow turbine for use as part of a gas-generator, and the design of a large-scale (1.2 m tip dia.) low-speed model of the high-speed turbine. Stream-line curvature throughflow, two-dimensional blade-to-blade and fully three-dimensional inviscid and viscous calculation methods have been used extensively in the analysis of the designs. The use of appropriate scaling parameters and their impact on turbine performance is discussed. A simple model shows, for example, how to model the blade lean in the inducer which serves to balance the effect of meridional curvature at inlet to the rotor and can be used to unload the rotor tip. A brief description of the low speed experimental facility is followed by a presentation and discussion of experimental results. These include surface flow visualisation patterns on both the rotor and stator blades and blade row exit traverses.
The Application of Particle Image Velocimetry (PIV) in a Short Duration Transonic Annular Turbine Cascade
Authors: Bryanston-Cross P. J. , Towers C. E. , Judge T. R. , Towers D. P. , Harasgama S. P. , Hopwood S. T.
Published: March 2015

A series of experiments have been performed to demonstrate the application of Particle Image Velocimetry (PIV) to turbomachinery flows. The tests were performed at transonic speeds on a fully annular engine size turbine nozzle guide vane. The vane cascade was installed in a short duration Isentropic Light Piston Cascade (ILPC) test facility operating with high inlet turbulence levels.

The technique has been shown to map the whole flow field with a resolution of 0.5 mm. The quality of the results obtained are not significantly affected by local turbulence rates. The accuracy of the measurements is put at around 4% of absolute velocity and is limited by the quality of the image on the film plane.

The velocities derived from the PIV images have been compared with predictions from a three-dimensional viscous numerical calculation. It is shown that the experimental and predicted results are in good agreement. It is considered that this technique has considerable potential in application to turbomachinery flow field diagnostics.
Unsteady Navier-Stokes Simulation of Transonic Cascade Flow Using an Unfactored Implicit Upwind Relaxation Scheme With Inner Iterations
Authors: Furukawa M. , Nakano T. , Inoue M.
Published: March 2015

An implicit upwind scheme has been developed for Navier-Stokes simulations of unsteady flows in transonic cascades. The two-dimensional, Reynolds-averaged Navier-Stokes equations are discretized in space using a cell-centered finite volume formulation and in time using the Euler implicit method. The inviscid fluxes are evaluated using a highly accurate upwind scheme based on a TVD formulation with the Roe’s approximate Riemann solver, and the viscous fluxes are determined in a central differencing manner. The algebraic turbulence model of Baldwin and Lomax is employed. To simplify grid generations, a zonal approach with a composite zonal grid system is implemented, in which periodic boundaries are treated as zonal boundaries. A new time-linearization of the inviscid fluxes evaluated by the Roe’s approximate Riemann solver is presented in detail. No approximate factorization is introduced, and unfactored equations are solved by a pointwise relaxation method. To obtain time-accurate solutions, 30 inner iterations are performed at each time step. Numerical examples are presented for unsteady flows in a transonic turbine cascade where periodic unsteadiness is caused by the trailing edge vortex shedding.
501F Compressor Development Program
Authors: Smed J. P. , Pisz F. A. , Kain J. A. , Yamaguchi N. , Umemura S.
Published: March 2015

As part of the WESTINGHOUSE-MHI 501F Development Program, a new 16 stage axial flow compressor has been designed. Reported here are elements of the aerodynamic and mechanical design as well as general design features. Overall performance test results are also presented which indicate that the compressor met or exceeded all expectations amenable to measurement during the full load shop test program.
Multikilowatt Lasers in Manufacturing
Authors: Banas Conrad M.
Published: March 2015

The fundamentals of laser beam interactions with materials are discussed briefly and unique laser processing capabilities are noted. Introduction of this processing capability to manufacturing is reviewed. Typical high volume production application requirements are identified and representative performance and production experience are described.

Specific multikilowatt laser welding, piercing and hardfacing applications in aerospace production are described. Evolution of production processes is discussed against the background of required processing capability. Also discussed are the unique laser processing capabilities which resulted in selection of the laser for production. Production experience is reviewed and cost saving factors are noted.
Measurements of the Entrainment Coefficient of Acoustically Pulsed Axisymmetric Free Air Jets
Authors: Vermeulen P. J. , Rainville P. , Ramesh V.
Published: March 2015

Novel direct measurements of the entrainment coefficient in the initial zone of a pulsating air jet have been successfully accomplished. A series of pulsating air jets flowing from different nozzle orifice sizes into surrounding air were investigated for the effects of jet axial length, excitation power and Strouhal number. The entrainment coefficient of the excited jet varied strongly with axial distance downstream of the orifice exit plane and with pulsation strength. The acoustic drive considerably increased the entrainment coefficient by up to 4.6 times at 10 diameters downstream of the nozzle. There was only a tendency for the entrainment coefficient to increase with the Strouhal number and hence an optimum Strouhal number for jet response was not found.
Study of External Dynamic Flap Loads on a 6 Percent B-1B Model
Authors: Seiner John M. , Manning James C. , Capone Francis J. , Pendergraft Odis C.
Published: March 2015

The origin of dynamic pressure loads on external divergent engine nozzle flaps of the B-1B aircraft was investigated in the NASA/LaRC 16 foot transonic tunnel using a 6% full span model with powered engine nacelles. External flap dynamic loads and afterbody drag associated with flap removal were measured using this model. Both dry and max. A/B power nozzles were evaluated in this study. As a result of this study the principle mechanisms responsible for high dynamic external flap loads were determined along with performance penalty associated with flap removal.
Rotordynamic Evaluation of an Advanced Multi-Squeeze Film Damper: Imbalance Response and Bladeloss Simulation
Authors: Walton J. F. , Heshmat H.
Published: March 2015

In this paper results of rotordynamic response and transient tests of a novel, high load squeeze film damper design, are presented. The spiral foil multi-squeeze film damper has been previously shown to provide two to four fold or larger increases in damping levels without resorting to significantly decreased damper clearances or increased lengths. By operating with a total clearance of approximately twice conventional designs, the non-linearities associated with high eccentricity operation are avoided. Rotordynamic tests with a dual squeeze film configuration were completed. As a part of the overall testing program, a flexible rotor system was subjected to high steady state imbalance levels and transient simulated bladeloss events for up to 0.254 mm (0.01 in) mass c.g offset or 180 gm-cm (2.5 oz-in) imbalance. The spiral foil multi-squeeze film damper demonstrated that the steady state imbalance and simulated bladeloss transient response of a flexible rotor operating above its first bending critical speed could be readily controlled. Rotor system imbalance sensitivity and logarithmic decrement are presented showing the characteristics of the system with the damper installed. The ability to accommodate high steady state and transient imbalance conditions make this damper well suited to a wide range of rotating machinery, including aircraft gas turbine engines.
A Chambered Porous Damper for Rotor Vibration Control: Part I — Concept Development
Authors: Tecza J. , Walton J.
Published: March 2015

In this paper a novel, high load chambered porous damper design, supporting analysis, and experimental results are presented. It was demonstrated that significant damping can be generated from the viscous discharge losses of capillary tubes arranged in chambered segments with large radial clearances and that the resulting damping is predictable and fairly constant with speed and eccentricity ratio. This design avoids the non-linearities associated with high eccentricity operation of conventional squeeze film dampers. Controlled orbit tests with a porous chambered configuration were completed and favorably compared with theoretical predictions. The ability to accommodate high steady state and transient imbalance conditions make this damper well suited to a wide range of rotating machinery, including aircraft gas turbine engines.
Dynamic Force Response of an Open Ended Squeeze Film Damper
Authors: San Andres L. A. , Meng G. , Yoon S.
Published: March 2015

The effects of whirl frequency and lubricant viscosity on the experimental pressure field and film forces in an open ended squeeze film damper test rig are presented. The measurements refer to circular centered journal motion of amplitude equal to one half the damper clearance (ε=0.5). The whirl frequency varied between 16Hz to 85Hz, while the lubricant temperature increased from 25°C to 45°C. The damper operated with levels of external pressurization which supressed lubricant cavitation. The experimental results show conclusivey that the radial film force is purely an inertial effect, i.e. it depends solely on the fluid density and the second power of the whirl frequency. The tangential film force shows a variation which depends on the viscous and inertial flow conditions in the squeeze film region. Correlation of experimental forces with conventional SFD models shows the radial force to be π times larger than the theoretical prediction, while the tangential force correlates well for low whirl frequencies and large lubricant viscosities.
A Gas Operated Bearing Damper for Turbomachinery
Authors: Vance John M. , Cardon Bradley P. , San Andres Luis A. , Storace Albert F.
Published: March 2015

A gas operated bearing damper for turbomachinery has been designed, analyzed, and experimentally investigated in the laboratory. The damper utilizes air bled off from the compressor to power an actuator through orifices with area modulated by the vibratory displacement at the bearing support. The design objective for this passive device is to make the actuating dynamic gas pressure phase lead the vibratory displacement by 90 degrees.

Several variations of the basic concept have been tested. An analysis was performed to guide the experiments. All of the designs tested to date can produce positive damping, and one particular design has produced a damping coefficient of 8756 N-s/m (50 lb-sec/in) with a power penalty of 5.2 KW (7 HP) at 310 KPa (45 psi). This design was installed on a laboratory rotor with flexibly supported ball bearings, and significant damping of the critical speed response was demonstrated.

The experimental results to date suggest that further research can produce significant improvements in performance, and the device appears to be especially adaptable to high temperature applications for aircraft engines.
Development Testing of Epicyclic Gearing
Authors: Yates D. E. , Lack G. J.
Published: March 2015

The increasing use of epicyclics for high powered marine and industrial applications has resulted in world wide interest in this type of gearing. The coaxial input and output, reduced losses, small size and low weight are some of the advantages.

The use of a full size development test rig using the power circulation method has been fundamental to the evolution of double helical, flexible annulus epicyclics, and has led to a detailed understanding of their operating principles. This understanding has been essential for the analytical modelling and the development of innovative design concepts.

The paper outlines some of the work which has been carried out in the test rig at NEI Allen Ltd - Allen Gears. The method of measuring the dynamic load sharing is discussed and some of the results which have led to improvements in the design and manufacturing methods are given.

Test rig work continues currently with the development of low noise gears and vibration isolation.
Application of Ceramics to Turbocharger Rotors for Passenger Cars
Authors: Katano Yasushi , Ando Motohide , Itoh Takane , Sasaki Masafumi
Published: March 2015

Nissan has been developing and marketing ceramic turbocharger rotors for over five years. This paper outlines the major theories and techniques used in ceramic fabrication, joining of ceramic and metal components and machining of ceramics. It also presents a dynamic stress analysis using DYNA3D and describes techniques used in performing impact damage experiments, reliability evaluation and lifetime prediction.
Heat Transfer in the Turbulent Boundary Layer With a Step Change in Surface Roughness
Authors: Taylor Robert P. , Taylor J. Keith , Hosni M. H. , Coleman Hugh W.
Published: March 2015

Measurements of Stanton numbers, velocity profiles, temperature profiles, and turbulence intensity profiles are reported for turbulent flat plate boundary layer flows with a step change in surface roughness. The first 0.9 m length of the test surface is roughened with 1.27 mm diameter hemispheres spaced 2 base diameters apart in a staggered array. The remaining 1.5 m length is smooth. The experiments show that the step change from a rough to a smooth surface has a dramatic effect on the convective heat transfer. In many cases, the Stanton number drops below the smooth-wall correlation immediately downstream of the change in roughness. The Stanton number measurements are compared with predictions using the discrete element method with excellent results.
Comparison of Time-Resolved Turbine Rotor Blade Heat Transfer Measurements and Numerical Calculations
Authors: Abhari R. S. , Guenette G. R. , Epstein A. H. , Giles M. B.
Published: March 2015

Time-resolved turbine rotor blade heat transfer data are compared with ab initio numerical calculations. The data was taken on a transonic, 4-to-1 pressure ratio, uncooled, single-stage turbine in a short duration turbine test facility. The data consists of the time history of the heat transfer distribution about the rotor chord at midspan. The numerical calculation is a time accurate, 2-D, thin shear layer, multiblade row code known as UNSFLO. UNSFLO uses Ni’s Lax-Wendroff algorithm, conservative boundary conditions, and a time tilting algorithm to facilitate the calculation of the flow in multiple blade rows of arbitrary pitch ratio with relatively little computer time. The version used for this work had a simple algebraic Baldwin-Lomax turbulence model. The code is shown to do a good job of predicting the quantitative time history of the heat flux distribution. The wake/boundary layer and transonic interaction regions for suction and pressure surfaces are identified and the shortcomings of the current algebraic turbulence modelling in the code are discussed. The influence of hardware manufacturing tolerance on rotor heat transfer variation is discussed. A physical reasoning explaining the discrepancies between the unsteady measurement and the calculations for both the suction and pressure surfaces are given, which may be of use in improving future calculations and design procedures.
Development of Ceramic Turbocharger Rotors for High Temperature Use
Authors: Kawase Hiroyuki , Matsuhisa Tadaaki , Kato Kiminari , Mizuno Takeyuki
Published: March 2015

A ceramic turbocharger rotor (CTR) for high temperature use has been developed. The features of this rotor are the use of silicon nitride which maintains high mechanical strength up to 1,200 °C and a new joining technique between the ceramic rotor and its metal shaft. The CTR is expected to cope with stoichiometrical mixture burning engines which produce a higher exhaust gas temperature for fuel economy, and the impact resistance of the rotor against foreign object damage (FOD) has been markedly increased, over that of earlier rotors, resulting in higher reliability.

This paper describes the development of ceramic turbocharger rotors for high temperature use focusing on the mechanical strength of silicon nitride and the joining of the ceramic rotor and its metal shaft.
Integrated Flight/Propulsion Control for Flight Critical Applications: A Propulsion System Perspective
Authors: Tillman Kenneth D. , Ikeler Timothy J.
Published: March 2015

The Pratt & Whitney and Northrop companies together, under the Air Force Wright Research and Development Center (WRDC) sponsored Integrated Reliable Fault-Tolerant Control for Large Engines (INTERFACE II) Program[1,2], designed and demonstrated an advanced real-time Integrated Flight and Propulsion Control (IFPC) system. This IFPC system was based upon the development of physically distinctive, functionally integrated, flight and propulsion controls that managed the Northrop twin engine, statically unstable, P700 airplane. Digital flight control and digital engine control hardware were combined with cockpit control hardware and computer simulations of the airplane and engines to provide a real-time, closed loop, piloted IFPC system. As part of a follow on effort, lessons learned during the INTERFACE II program are being applied to the design of a flight critical propulsion control system. This paper will present both the results of the INTERFACE II IFPC program and approaches toward definition and development of an integrated propulsion control system for flight critical applications.
Acousto-Ultrasonic NDE of Ceramic Matrix Composites
Authors: Lott L. A. , Kunerth D. C. , Characklis G. W.
Published: March 2015

Acousto-ultrasonics, a relatively new approach for nondestructive evaluation (NDE) of material components, is particularly promising for characterization of mechanical properties and detection of defects in composites. This paper describes application of the technique, which measures the ability of a material component to transmit and/or sustain elastic waves, to characterizing fiber-matrix interfaces in ceramic matrix composites. Experimental measurement techniques and data processing and analysis methods used for the study are presented along with observed correlations between material properties and measured acousto-ultrasonic parameters.
Development Study of 1500°C Class High Temperature Gas Turbine
Authors: Kano K. , Matsuzaki H. , Aoyama K. , Aoki S. , Mandai S.
Published: March 2015

This paper outlines the development programs of the next generation, 1500°C Class, high efficiency gas turbine. Combined cycle thermal efficiency of more than 55% (LHV) is expected to be obtained with metallic turbine components. To accomplish this, advancements must be made in the key technologies of NOx control, materials and cooling.
A Combined Gas Turbine Control and Condition Monitor
Authors: DeMoss S. H.
Published: March 2015

To date, condition monitors have been generally implemented as add-on systems to industrial gas turbine installations. This paper describes the combining of the condition monitor with the gas turbine control into a highly integrated unit. Because of the reduced number of components involved, this provides a more robust system. System wiring is simplified, eliminating the need for duplicate wiring harnesses. In addition, a combined system simplifies operator interface and reduces the number of tasks the operator is required to perform.
MVC-2M Fault Diagnosis System and its Application
Authors: Xu G. P. , Lu W. Z. , Wu X. Q. , Weng W. X. , Ge N. M. , Guo X. Y. , Zhu J. H. , Bian X. J.
Published: March 2015

The MVC-2M Fault Diagnosis System — an achievement of the national key research task in this field is presented in this article. The system can be used in various fields such as marine power engines, power generation, petrochemical industry, aviation and space, machine building etc. The basic functions of this system include real-time condition monitoring, on-line and off-line fault diagnosis, establishment of operation database, storage of fault data in blackbox, calibration of vibration measuring instruments, analysis of structural dynamic characteristics, local dynamic balancing, and so on.

This article also presents several practical experieces during its term of service in Chinese naval vessels and power stations. It is widely confirmed that the MVC-2M system is essential to forecast the faults which probably would happen and thus is successful for avoiding the serious damage of the machines in motion.
A Multiple-Inlet Core for Gas Turbine, Pulse, Pressure-Gain Combustors
Authors: Kentfield J. A. C. , Speirs B. C.
Published: March 2015

Prior tests showed that a maximum increase of stagnation pressure equal to 4% of the compressor absolute delivery pressure was obtained on a very small gas turbine equipped with a prototype, valveless, pulse, pressure-gain, combustor. Accordingly, a new core pulse-combustor has been developed for a proposed pulse, pressure-gain, combustor for larger, more representative, gas turbines. The new core pulse-combustor differs from the earlier prototype design in that the single inlet passage has been replaced with four parallel inlet passages. It is shown that this concept reduces the time required for pre-combustion mixing of the air, fuel and products in the combustion zone. This results in the overall length of the combustor being reduced to about 60% of that required for a single inlet design. It was concluded, on the basis of tests, that a pulse, pressure-gain, combustor incorporating the new core unit should be capable of generating a maximum stagnation pressure-rise of about 10% of the compressor delivery pressure with a volumetric loading 3 to 4 times that of the original prototype.
Coherent Structure Identification in a Lobed Mixer
Authors: Ukeiley L. , Wick D. , Glauser M.
Published: March 2015

The influence of large scale structures on the flow in a lobed mixer (a device utilized to enhance streamwise vorticity for increased mixing) is examined by a pseudo flow visualization method (v. Delville et al. 1988), and the Proper Orthogonal Decomposition (POD) (v. Lumley 1967). The pseudo flow visualization method utilizes specially designed hot wire rakes with high spatial resolution to provide the capability of plotting instantaneous velocity profiles. In this work, a rake of 15 hot wires is used to provide these profiles for a velocity ratio of 2:1, at several positions downstream of the lobed mixer. From these profiles a detailed description of the flow field is achieved. In particular, from this information, an idea of the spatial extent and shedding frequency of the large scale structures is determined. The shedding frequencies found are consistent with those found from spectral measurements. A one-dimensional version of the POD is then applied, which utilizes the measured streamwise velocity two-point correlation tensor. The pseudo flow visualization technique is then used to view the contribution from each proper orthogonal mode to the instantaneous signal and comparisons made to the full signal.
Simple Formulae for Optimal Solidity of Two-Dimensional Compressor Cascades Based on Diffusion Concept
Authors: Liu Gao-Lian
Published: March 2015

The optimal solidity problem of two-dimensional (2-D) compressor cascades is formulated as two nonlinear programming problems, in which either the profile losses are minimized or the blade loading is maximized subject to an inequality constraint on the equivalent diffusion ratio or diffusion factor (Lieblein, 1959, 1965). Analytical solutions to these two mathematical programming problems are obtained in form of simple formulae, which are very convenient for everyday practical use. A rational way for extending their application to 3-D compressor bladings is also suggested.
U.S. Navy On-Line Compressor Washing of Marine Gas Turbine Engines
Authors: Margolis Harry
Published: March 2015

Compressor waterwashing is a necessary maintenance practice to maintain compressor efficiency for all types of gas turbine engines. This paper discusses U.S. Navy involvement with prototype on-line compressor cleaning systems on marine gas turbine engines. These engines include the General Electric LM2500, the Garrett 831-800, and the Allison 501-K17.
Cascade Testing of Ceramic Vanes for Industrial Gas Turbines
Authors: Tsuji I. , Aoki S. , Miyazaki S. , Hara Y. , Furuse Y. , Hamada S.
Published: March 2015

The development of uncooled ceramic vanes for a 20MW class gas turbine with the firing temperature of 1300°C is progressing.

The 1st stage ceramic vanes were made of sintered SiC or sintered Si3N4, and the 2nd stage ceramic vanes were made of sintered Si3N4. These vanes were tested by means of hot and high pressure cascade testing simulating actual gas turbines operation.

After minor modifications, we have succeeded in developing sound ceramic vanes which are durable against high thermal stress which occurs during the transient of trip (emergency shutdowns or fuel tripouts), and obtained great results for the practical application.

In this paper, details of the ceramic vanes’ structure and cascade testing are described and the results of the tests are discussed.
A New Base Pressure Correlation for Transonic and Supersonic Flows
Authors: Bölcs A. , Sari O.
Published: March 2015

This paper presents a new base pressure correlation for transonic and supersonic flow conditions obtained from systematic measurements in linear and annular turbine cascades and by considering the physics of the flow in choked cascades. The correlation is valid in the range from near sonic outlet flow velocity to limit loading.

Most of the presently used base pressure correlations show deviations from experimental results for several profile types. One of the reasons is the uncertainty in the evaluation of the downstream pressure in the cascade used as a reference pressure.

In the model proposed here, another reference value is defined instead, namely the Mach number of the recompression point at the end of the triangular base pressure region. This recompression Mach number is obtained in an indirect way from the measured pressure distribution on the profile, i. e., by applying characteristic relations.

The advantage of this base pressure correlation is that a unique relationship between the base pressure and an arbitrarily defined reference pressure (for example, the back pressure) can be established.
Humidity Effects on Gas Turbine Performance
Authors: Bird J. , Grabe W.
Published: March 2015

Moisture in the intake air of a gas turbine can affect its operation and performance in two different ways: by possible condensation in the inlet and by changing the gas properties throughout the cycle. Condensation can be controlled by restricting engine operation with limits on relative and absolute humidities. Two fundamental correction approaches for the effects of humidity on major engine parameters were investigated; they were found to compare very well. Both methods correct parameters as a function of absolute humidity, yielding corrections of between 0.1 and 0.8%, for high humidity test conditions. Additional operational, engine-specific humidity corrections were examined: some notable differences were observed. Recommendations are made for the correction of major performance data for absolute humidity.
Preliminary Design of Axial Compressors Using Artificial Intelligence and Numerical Optimization Techniques
Authors: Holt George , Bassler Stuart
Published: March 2015

This paper discusses an automated method for optimizing multistage axial compressor designs using a generic design software shell called Engineous®, coupled with an aerodynamic compressor design program called CUS5 (Compressor Unification Study 5). Engineous combines heuristic searching and numerical optimization techniques, and expert systems to explore the design space of turbomachinery components by iterating preliminary design analysis programs written in languages such as FORTRAN and C. The application design and development process and the lessons learned are discussed for the Engineous/CUS5 axial compressor application. This particular application calculates and maintains compressor stall prediction values while optimizing at the operating (design) point, and requires a design vs. stall comparison during each iteration. A trial compressor design problem was investigated using the Engineous application, and the preliminary results of the study are included. Also introduced is a method for varying flowpath walls using shape criteria rather than radii points.
A Pressure Based Calculation for Shocked Flow in Nozzles
Authors: Du Z. Q. , Xu J. Z. , Du J. Y.
Published: March 2015

The pressure based algorithm for incompressible flow has been extended to the flows at all speeds in arbitrary configuration. In order to obtain a more acurate pressure correction equation the mixed tensor is used in the momentum equations in a nonorthogonal curvilinear coordinates. In discretizing the convection terms of the momentum equations and the density terms of the continuity equation the upwind scheme is used and the problem on reflection of the exit pressure in a shocked flow is studied. The numerical examples show that this method can calculate the flow field in a nozzle with or without a shock, and the location of the shock computed is quite exact.
A Universal Turboprop Engine Dynamometer Test Cell
Authors: Mainville D. , Melfi D. , Whiting M.
Published: March 2015

Pratt & Whitney Canada produces a wide range of aircraft engines and this has led to a concerted effort to standardize and streamline its production engine test facilities. P&WC produce two very different series of turboprop engines, the PW100 with a conventional intake and exhaust arrangement and the PT6 with its reverse flow arrangement. A dynamometer test cell capable of testing both these engine series has been designed and built at Longueuil and is now in operation. The changeover from one model to the other can be carried out by an operator in less than two hours and requires no special tooling or manpower. This paper discusses the solutions developed to overcome the inherent problems of intake and exhaust arrangement, engine mounting, slave equipment requirements etc. generated by testing two very different families of engines in the same test cell coupled with the need to incorporate the efficiency and ease of operation required of a production facility.
Enhanced Full Coverage Impingement Heat Transfer With Obstacles in the Gap
Authors: Hussain R. A. A. Abdul , Andrews G. E.
Published: March 2015

Impingement heat transfer with turbulence enhancing obstacles in the impingement gap were investigated and compared with the unobstructed flow situation. The objective was to significantly enhance flat plate impingement heat transfer for gas turbine combustor external wall cooling applications. Large flow blockages were used in the form of ribs and slotted ribs. The latter were found to have the best heat transfer enhancement of up to 23% at the trailing edge. The main effect of the blockage was to considerably reduce the influence of crossflow on the heat transfer by preventing the deflection of the impingement jets by the crossflow.
Combined Effects of Axial- and Radial-Gap Spacing on the Mass Transfer Characteristics of a Shrouded Rotor-Stator System
Authors: Chyu M. K. , Bizzak D. J.
Published: March 2015

Heat transfer characteristics of a shrouded rotor-stator system are examined using a mass transfer analog technique. Both local and average mass-transfer coefficients for a naphthalene-coated disk rotating in a quiescent environment are obtained for 4.0×104 ≤ Re ≤ 2.4×105. The measured results, which correlate well with theoretical predictions, are used to evaluate the influence of radial-gap clearance and axial-gap spacing on average and local mass-transfer rates in a shrouded rotor-stator with no superposed coolant flow. Similar to a rotor-stator system without a shroud, a reduction in the axial gap tends to decrease the average mass transfer, with the magnitude of the decrease being inversely proportional to the Reynolds number. Such a reduction in mass transfer is also found to be influenced by the radial clearance gap. A reduction of the radial clearance from a/D=0.042 to 0.020 is shown to decrease the average Sherwood number by approximately 20 percent of the corresponding free disk value. Local mass transfer distributions illustrate a more significant axial gap effect. For small axial-gap spacings, local Sherwood number profiles are no longer uniform across the rotor face, but exhibit a significant increase near the rotor edge. The magnitude of this increase near the disk edge is shown to be inversely proportional to the radial clearance gap and the rotational Reynolds number.
Development of 6MW-Class Gas Turbine MF-61
Authors: Terazaki M. , Fukue I. , Tsukuda Y. , Aoki S.
Published: March 2015

The MF-61 is a 6MW-class heavy duty gas turbine which was developed for cogeneration application. A single can type combustor with wide fuel flexibility and advanced high efficiency compressor has been adopted for this engine. The combustor outlet temperature is designed at 1150°C. This paper describes the design concepts of the machine, the design features, and the verification programs carried out in Takasago, Japan. The results of the full load shop test verified that the performance, the mechanical characteristic and the emission well satisfied the initial design goals.
Boundary Layer Transition Under the Presence of Discrete Frequencies in the Freestream Turbulence Spectrum
Authors: Costa Jorge , Arts Tony
Published: March 2015

The flow in turbomachines is characterized by a high turbulent activity; its spectrum frequently reveals energy peaks at privileged frequencies. Most often they influence the boundary layer transition onset. This type of forced transition was studied at the von Karman Institute in a low speed wind-tunnel along a flat test surface. Discrete frequency energy peaks were introduced into the mainstream flow by acoustic means. The receptivity of the boundary layer flow to the acoustic excitation frequency was put in evidence both by the frequency dependent transition Reynolds number and the streamwise intermittency factor distributions. The intermittency measurements were performed with the help of a conditional sampling technique; the later included a new approach to the positioning of the laminar-turbulent decision threshold. The growth of selected oscillation modes were compared in a natural and a forced transition situation. A model providing an estimation, within the transition region, of the turbulence level profiles and the skin friction coefficient was finally proposed.
Calculations of Fuel NO Formation in a Gas Turbine Combustor
Authors: Overcamp Thomas J. , Agrawal Ajay K. , Cheng Wei-Seng , Yang Tah-Teh
Published: March 2015

PCGC-2, a two-dimensional combustion code for pulverized coal gasification and combustion, and PHOENICS, a general purpose fluid dynamics code, were adapted for use in simulating the conversion of fuel nitrogen to nitric oxide, NO, in a gas turbine combustor using low-Btu fuel. A two-reaction global mechanism was used to describe the oxidation of fuel nitrogen. PCGC-2 is limited to two-dimensional, axisymmetric calculations. Both two- and three-dimensional simulations were made with PHOENICS. A parametric study was conducted to determine the variation of fuel nitrogen conversion with changes in the input variables including the inlet fuel nitrogen concentration and swirl numbers. The fuel nitrogen conversion predicted with both codes is similar to those reported in experimental studies on gaseous fuels. The conversion decreased with increasing fuel nitrogen inputs as shown in experimental data. The fuel conversion predicted in three-dimensional simulations for an industrial gas turbine was slightly higher than those in simplified two-dimensional simulations.
A Non-Dimensional Conceptual Design Procedure for the Vaneless Volutes of Radial Inflow Turbines
Authors: Whitfield A. , Noor A. B. Mohd
Published: March 2015

The requirements for the volute of a radial inflow turbine are that it should collect the working fluid, deliver it to the turbine rotor as efficiently as possible and provide the desired rotor inlet conditions. The overall performance requirements of the turbine leads to the rotor design and the identification of the desired flow conditions at rotor inlet in terms of the magnitude and direction of the absolute Mach number, see Whitfield (1990). The volute must then be designed to ensure that the desired rotor inlet conditions are attained.

A non-dimensional conceptual design procedure for a vaneless turbine volute is described. Based on a knowledge of the magnitude and direction of the absolute Mach number at rotor inlet the overall dimensions of the volute in terms of the radius ratio and flow area ratio are first established. The overall design is then developed to provide the variation of the volute centroid radius and area ratio with azimuth angle. A trapezoidal cross-sectional shape is then used to establish the outer dimensions of the volute.

The non-dimensional design procedure assumes a one-dimensional compressible flow and as such relies on the empirical specification of the dissipation of angular momentum, the dissipation of energy, and the deviation of the swirling flow from that of a free vortex. The effect of the uncertainties associated with the empirical data on the volute design geometry is assessed.
Investigation Into the Adaptibility of the Modified Exhaust-Heated Gas Turbine Installation to the Operation With an Air Extraction
Authors: Golinski Joseph A.
Published: March 2015

This paper is a continuation of investigation into the possibilities of industrial application of the modified exhaustheated gas turbine installation with increased thermal efficiency, described in the ASME-Paper 90-GT-369. According to the author’s conception this turbine installation may be very useful when interacting with some chemical processing installations, e.g. by feeding a coal gasifier with pre-heated compressed air. It would then be a turbine system with an air extraction, performing a double duty. The heat contained in the air extracted from the gas turbine system plus the mechanical/electrical power produced create permanent full load conditions yielding the maximum thermal efficiency of the system. It has been found that for some point of extraction from a gas turbine plant of 33 % efficiency (without air extraction) the overall efficiency may raise to some 60 or even 73 %. This is possible due to the fact that the enthalpy increase of the extracted air is calculated with respect to that of the compressor inlet air. Moreover the air supplied to the gasifier does not expand in the turbine and does not perform any mechanical work.
Evaluation of Simple Aluminide and Platinum Modified Aluminide Coatings on High Pressure Turbine Blades After Factory Engine Testing
Authors: Conner Jeffrey A. , Moore David A. , Wustman Roger D.
Published: March 2015

This paper presents results from recent factory engine testing of simple aluminide coatings produced using pack cementation processes and platinum modified aluminide coatings produced using both pack cementation and chemical vapor deposition processes. These coatings were evaluated on DS nickel base superalloy high pressure turbine blades in a commercial high bypass turbofan engine. Operating conditions were such that turbine inlet air contained up to 3 ppb of sodium. Details of the factory engine testing, coating selection and application, and environmental protection provided by the coatings are highlighted. Future testing plans are also presented.
Investigation on Flow Mechanism of Secondary Erosion
Authors: Ling Zhiguang , Yuan Yiqing
Published: March 2015

Secondary erosion caused by particulate flow is a new research direction. On the basis of numerical analysis of the trajectory of particle motion in rotating gas flow, its equilibrium condition and causes of aggregation, a physical flow model of secondary erosion is suggested. By this model the mechanism of secondary erosion caused by particulate gas flow could be primarily explained. The vortex chamber experiment verifies the particle aggregation tendency in vortex flow and the experiment of particle deposition in bending tube proves in certain extent the correctness of the suggested model.
Combustion of LCV Coal Derived Fuel Gas for High Temperature, Low Emissions Gas Turbines in the British Coal Topping Cycle
Authors: Kelsall G. J. , Smith M. A. , Todd H. , Burrows M. J.
Published: March 2015

Advanced coal based power generation systems such as the British Coal Topping Cycle offer the potential for high efficiency electricity generation with minimum environmental impact. An important component of the Topping Cycle programme is the development of a gas turbine combustion system to burn low calorific value (3.5–4.0 MJ/m3 wet gross) coal derived fuel gas, at a turbine inlet temperature of 1260°C, with minimum pollutant emissions.

The paper gives an overview of the British Coal approach to the provision of a gas turbine combustion system for the British Coal Topping Cycle, which includes both experimental and modelling aspects. The first phase of this programme is described, including the design and operation of a low-NOx turbine combustor, operating at an outlet temperature of 1360°C and burning a synthetic low calorific value (LCV) fuel gas, containing 0 to 1000 ppmv of ammonia. Test results up to a pressure of 8 bar are presented and the requirements for further combustor development outlined.
The Effects of Aerothermal Component Performance on Large Civil Turbofans
Authors: Collins A. G. , Hill R. J.
Published: March 2015

In the 40 years of commercial gas turbine avaiation fuel consumption has almost halved. This has been brought about by almost equal improvements in propulsive efficiency — by use of the bypass principle, improvements in cycle efficiency — largely due to improvements in material capability, and lastly component efficiency — due to the advent of CFD analysis. The paper examines the capability of gaining improvements over the next 30 years in each of the above areas and highlights in particular the need for continuing effort on improving all aspects of component efficiency since this, in addition to providing considerable benefits in its own right, also enables further benefits to be gained in propulsive and cycle efficiency.
Study on the Influence of Air Bleeds on the Behaviour and on the Performance of Gas Turbine Engines
Authors: Torella Giovanni
Published: March 2015

The influence of air system an engine performance and behaviour is considered. A method based on the polytropic efficiency concept has been developed in order to calculate the thermodynamic characteristics of air bleed. This method has been included in the “Design Point” and “Off Design” codes of different configuration engines. The paper shows the wide applications of the programs for several calculations. Moreover the results of the faults of air system are shown by both diagnostic and fault simulation computer programs.
A Simple Model to Simulate Subsonic Intakes and Propelling Nozzles of Aircraft Gas Turbine Engines
Authors: Ismail I. H. , Bhinder F. S.
Published: March 2015

In this paper the subsonic intake and the propelling nozzle of aircraft gas turbine engines are modeled for the purpose of simulate. Each component is considered as a variable area duct which is divided into a number of elemental sections. Flow properties are calculated in a step by step manner in each section taking into account friction and area change. The underlying theory of the model and a brief description of the computer program are given. The program has been written in Fortran 77 and runs on IBM AT or 100% compatible micro computers.
A New and Simple Concept to Replace “Film Effectiveness”
Authors: Adiutori Eugene F.
Published: March 2015

Film effectiveness (η) is used to describe the adiabatic wall temperature (TAW) which results when a colder or hotter fluid is injected into the boundary layer. Eq (1) is the defining equation for η:(1)(TMS−TAW)=η(TMS−TF)where TF and TMS refer to the temperatures of the film and mainstream fluids.

Literature data indicate that η is a constant coefficient in Equation 1 only in applications where TF/TMS is restricted to a narrow band. If TF/TMS varies over a wide band, such as in gas turbines and rockets, then η is a variable in Eq 1.

This article demonstrates that, in applications where TF/TMS varies over a wide band, the film effectiveness concept is neither simple nor direct, and it complicates and confuses the solution of practical problems.

This article also presents a new and simple concept to replace film effectiveness. The new concept retains the TF/TMS parameter used in film effectiveness methodology, but it replaces η with TAW/TMS.

The particular advantage of the new concept is that it describes TAW in a simple and direct way even if TF/TMS varies over a wide band. The end result is that, in applications such as gas turbines and rockets, the new concept is much simpler and therefore much better than the film effectiveness concept it replaces.
A Low Noise Propulsion Concept for the Supersonic Transport
Authors: Champagne G. A. , Allen G. E. , Palmieri M. , Adler R. M.
Published: March 2015

The major challenges with the design of propulsion systems for High speed Civil Transports (HSCT) are complying with FAR and EPA environmental standards while powering an economically acceptable aircraft. These issues create a dilemma in engine design because low exhaust jet velocities are required to meet takeoff noise regulations while high exhaust jet velocities are required for economical supersonic cruise operation. Previous studies have shown that to meet FAR Stage 3 noise regulations, engines incorporating mechanical/thermal noise suppression concepts must be oversized by 50 to 80% relative to the size that will provide the maximum aircraft economics.

In order to achieve the Stage 3 noise levels without oversizing the engine, the engine airflow must be increased by 120% during takeoff operation to reduce the average exhaust velocity to an acceptable level. This paper will examine a concept that brings in 74% additional airflow into the engine’s inlet and 46% into the engine’s exhaust nozzle. The impacts of this concept on engine design, performance, size and weight and on aircraft takeoff gross weight (TOGW) and range are evaluated. For the same TOGW aircraft, this noise reduction concept provides a 70% range improvement relative to engines which incorporate mechanical/thermal noise suppressors. This concept was developed under a NASA sponsored program.
Inlet Planar Waves: A Current Perspective
Authors: Ball W. H.
Published: March 2015

A review of inlet planar total pressure waves has been accomplished by the SAE S-16 Committee. The review was conducted to determine the feasibility of developing a consensus methodology that can account for the effect of planar waves on inlet/engine compatibility. The elements of the review included a problem assessment to define the scope and severity of the problem, a discussion of possible approaches to defining a methodology that can relate planar waves to engine response, conclusions, and recommendations. This paper discusses the major findings of the committee effort.