bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Incident Wake Conditions on the Mean Heat Transfer of an Airfoil
Authors: Dullenkopf K. , Schulz A. , Wittig S. 
Published: March 2015

The flow phenomena of wakes shed by upstream blade rows is a well–known problem in turbomachinery which influences blade forces, vibrations, losses and heat transfer. With respect to the heat load to turbine blades this problem becomes even more complex because of the interaction between wake, potential flow and the boundary layer along the surface of the airfoil.
Experimentally evaluated mean heat-transfer coefficients obtained under different unsteady initial conditions are reported. The heat–transfer measurements have been carried out in the cascade test facility at the ITS in Karlsruhe using a rotating bar wake generator placed upstream of the cascade to simulate the wake passing process. The variation of the wake parameters includes different wake passing frequencies, cascade inlet Reynolds numbers and wake inclination angles. In addition, the relevant parameters of the unsteady wake have been measured by means of a fixed hot–wire anemometer using the ensemble average technique. The results are compared to those from the literature for the wake of a cylinder in cross–flow. They also serve as experimental base for parallel theoretical analyses.
Similarity Behavior in Transitional Boundary Layers Over a Range of Adverse Pressure Gradients and Turbulence Levels
Authors: Gostelow J. P. , Walker G. J. 
Published: March 2015

Boundary layer transition has been investigated experimentally under low, moderate and high free-stream turbulence levels and varying adverse pressure gradients. Under high turbulence levels and adverse pressure gradients a pronounced subtransition was present. A strong degree of similarity in intermittency distributions was observed, for all conditions, when the Narasimha procedure for determination of transition inception was used.
Effects of free-stream turbulence on the velocity profile are particularly strong for the laminar boundary layer upstream of the transition region. This could reflect the influence of the turbulence on the shear stress distribution throughout the layer and this matter needs further attention. The velocity profiles in wall coordinates undershoot the turbulent wall layer asymptote near the wall over most of the transition region.
The rapidity with which transition occurs under adverse pressure gradients produces strong lag effects on the velocity profile; the starting turbulent boundary layer velocity profile may depart significantly from local equilibrium conditions. The practice of deriving integral properties and skin friction for transitional boundary layers by a linear combination of laminar and turbulent values for equilibrium layers is inconsistent with the observed lag effects.
The velocity profile responds sufficiently slowly to the perturbation imposed by transition that much of the anticipated drop in form factor will not have occurred prior to the completion of transition. This calls into question both experimental techniques which rely on measured form factor to characterize transition and boundary layer calculations which rely on local equilibrium assumptions in the vicinity of transition.
Flight Development of the RTM 322 Engine
Authors: Sewell Peter , Scears Paul E. 
Published: March 2015

The RTM 322 engine, under development by Rolls-Royce Turbomeca Ltd, is a viable candidate engine for future incorporation in S-70, H-60, EH101 and NH90 helicopters. An important ingredient in the development of the engine is its flight testing, currently being carried out in a Sikorsky S-70C (Civil version of the U S Army UH60 BLACK HAWK). This has not only served realistically to uncover and correct at very early stages those types of problem common to the development of all new engines but has also equally afforded an early look at installation, control and engine/airframe dynamic characteristics which, of course, will simplify later Production Series incorporation.
A brief description of the RTM 322 engine design and its development status is given followed by a summary of the installation and flight testing in the S-70C. Ground and flight test results in the S-70C are discussed and data and photographs presented.
Development of Corrosion Resistant Coatings for Marine Gas Turbine Applications
Authors: Nagaraj B. A. , Wortman D. J. , Maricocchi A. F. , Patton J. S. , Clarke R. L. 
Published: March 2015

The performance of a number of selected diffusion and overlay coatings was evaluated using an atmospheric pressure burner rig; the test environment contained compounds of vanadium, sodium and sulfur. The tests were designed to simulate the deposit chemistry and sulfur trioxide partial pressures expected in a marine gas turbine engine operating on contaminated fuel. The tests were performed for up to 1000 hours at 1300°F and 1650°F. At 1650°F, virtually all the coatings tested were severely corroded, emphasizing the necessity of improved coating materials such as ceramics to resist vanadic corrosion. At 1300°F, FeCrAlY, pack chromide and CoCrAlY coatings with high chromium performed well.
Yttria stabilized zirconia coatings, with selected bond coats, were evaluated with fuels containing low (0.3ppm) and high (21ppm) concentrations of vanadium in atmospheric burner rig at 1650°F. Reaction products, primarily yttrium vanadate, were observed in both tests. The results are discussed in terms of bond coat corrosion and chemistry of the test environment.
Flow Visualization in a Simulated Brush Seal
Authors: Braun M. J. , Hendricks R. C. , Canacci V. 
Published: March 2015

A method to visualize and characterize the complex flow fields in simulated brush seals is presented. The brush seal configuration was tested in a water and then in an oil tunnel. The visualization procedure revealed typical regions that are rivering, jetting, vortical or lateral flows and exist upstream, downstream or within the seal. Such flows are engendered by variations in fiber void that are spatial and temporal and affect changes in seal leakage and stability.
While the effects of interface motion for linear or cylindrical configurations have not been considered herein, it is believed that the observed flow fields characterize flow phenomenology in both circular and linear brush seals. The axial pressure profiles upstream, across and downstream of the brush in the oil tunnel have been measured under a variety of inlet pressure conditions and the ensuing pressure maps are presented and discussed.
Heat Transfer From a Rotating Disc
Authors: Dibelius G. H. , Heinen M. 
Published: March 2015

The local heat transfer from a plane rotating disc enclosed in a casing has been studied experimentally. The disc of 800 mm diameter can be run up to 2000 min−1 at axial distances between disc and casing varied between 5 and 55 mm. Centrifugal or alternatively centripetal flow of cooling air at rates up to ṁ = 1 kg/s can be applied, both with or without an inlet swirl.
With the disc rotating in a closed casing (ṁ = 0 kg/s) the influence of the characteristic dimensionless groups on the local heat transfer has been investigated. At a fixed radius, a variation of the local Reynolds Number by either speed or density results in corresponding changes of the heat transfer. However, with a variation of the radius different heat transfer-Re relations are found. In fact, the temperature distribution in the gas caused by the heat flux results in an additional influence of free convection, to be expressed by a Grashof Number. This is confirmed by a comparison of the experimental results with calculations based on Reynolds Analogy and measured friction coefficients. The discrepancies found can be explained only, if in addition to the limitations of the analogy, the influence of free convection is taken into account. Additional results of ongoing experiments concerning the influence of the geometry of the cavity between disc and casing, of the coolant flow rate and of the swirl are presented.
Numerical Prediction of Film Cooling Effectiveness and the Associated Aerodynamic Losses With a Three-Dimensional Calculation Procedure
Authors: Dibelius G. H. , Pitt R. , Wen B. 
Published: March 2015

Film cooling of turbine blades by injecting air through holes or slots affects the main stream flow. A numerical model has been developed to predict the resulting three-dimensional flow and the temperature pattern under steady flow conditions. An elliptic procedure is used in the near injection area to include reverse flow situations, while in the upstream area as well as far downstream a partial-parabolic procedure is applied. As first step an adiabatic wall has been assumed as boundary condition, since for this case experimental data are readily available for comparison.
At elevated momentum blowing rates, zones of reverse flow occur downstream of the injection holes resulting in a decrease of cooling efficiency. A variation of the relevant parameters momentum blowing rate m, injection angle α and ratio of hole spacing to diameter s/d revealed the combination of m ≈ 1, α ≈ 30° and s/d ≈ 2 to be the optimum with respect to the averaged cooling efficiency and to the aerodynamic losses. Cooling is more efficient with slots than with a row of holes not considering the related problems of manufacture and service life. The calculated temperature patterns compare well with the experimental data available.
Energy Exchange and Secondary Losses Prediction in High Speed Axial and Radial Compressors
Authors: Kaldellis J. K. , Ktenidis P. D. , Kodossakis D. E. 
Published: March 2015

In this paper an extension of our secondary flow calculation method is presented in order to estimate the energy exchange and the secondary losses in axial and radial compressors.
Although it is well known today that end-wall shear layers play a major role in the performance of the compressors, there are only few secondary flow methods able to predict realistically the behaviour of real machines. For this purpose a new theory was developed which extends Mellor’s basic principles and uses our previous work, including the complete form of meridional vorticity transport equation.
A coherent model for the real work exchange between the fluid and the machine has been developed, as well as for the distribution of secondary losses, not only at the compressor’s exit but also at every station through the machine. An expression for the added work due to the secondary field is also given. Finally the influence of secondary losses in the overall efficiency is well estimated.
This work has been successfully applied to a highly loaded compressor cascade, as well as to a transonic axial compressor and to a radial one-stage one. Comparison between theoretical and experimental results is also presented.
CT7-6: The Most Recent T700 Growth Derivative Engine
Authors: Kastrineli P. L. , Lightfoot W. E. 
Published: March 2015

In June 1988, the most recent growth derivative of the successful T700 family of turboshaft/turboprop engines, the CT7–6, received its FAA type certificate. The CT7–6 is the latest model in the extensive T700/CT7 family of engines. Its design and certification program were the result of the growth derivative approach to meeting the customers’ demand for more power. This approach has been successfully used by GE Aircraft Engines to grow the T700/CT7 family to meet the needs of a wide variety of customers and aircraft applications around the world. T700/CT7 engines provide power to 14 different aircraft applications and have accumulated over 4.5 million hours of operation on nearly 6,000 engines.
This paper traces the evolution of the CT7–6 model and discusses the technology enhancements which were incorporated to make it the most powerful member of the T700/CT7 family. A description is given of the synergism in the design and test phase of the CT7–6, which resulted from the derivative approach in combination with an integrated development program that simultaneously qualified/certified four T700/CT7 engine models. The paper also reviews the initial operator experience with the CT7–6 in a unique new European aircraft, the EH Industries EH101 helicopter.
T407/GLC38: A Modern Technology Powerplant
Authors: Zoccoli Michael J. , Klassen David D. 
Published: March 2015

The T407/GLC38 turboprop/turboshaft engine is a 6000 shaft horsepower (SHP) class gas turbine engine currently under joint development by Textron Lycoming of Stratford, Connecticut, and GE Aircraft Engines of Lynn, Massachusetts, with Bendix Control of South Bend, Indiana, a division of Allied Signal; Ruston Gas Turbines Limited of Great Britain, part of GEC ALSTHOM; and Steel Products Engineering Company (SPECO) of Springfield, Ohio.
The powerplant is derived from the highly successful GE27 Modern Technology Demonstrator Engine (MTDE) program, which was conducted under the auspices of the U.S. Army in the mid-1980s.
The T407 turboprop is currently under development for the U.S. Navy’s new P-7A anti-submarine warfare (ASW) aircraft. The P-7A will replace the P-3 and is under contract to Lockheed Aeronautical Systems Company (LASC). A T407 turboshaft model is also in development.
The GLC38 commercial turboprop version, planned for both business and commuter aircraft, draws considerably on lessons learned through GE and Textron Lycoming’s extensive commercial experience, thereby ensuring the latest state of the art in maintainability, life, reliability, and ease of operation.
The T407/GLC38 engine development program, scheduled for completion in December 1991, is uniquely defined to meet the stringent requirements of both Federal Aviation Administration (FAA) regulations and Military Specification MIL-E-008593E. The engine’s primary identity will be commercial, however, as per agreement with the U.S. Navy.
The engine’s gas generator core is also part of a joint venture between the Garrett Engine Division of Allied Signal Corporation and GE. Garrett is responsible for developing the fan and power turbine for a new generation turbofan engine, the CFE738.
This paper describes the key features of the T407/GLC38 engine design, performance, and development program.
T406 Engine Development Program
Authors: Arvin John R. , Bowman Mark E. 
Published: March 2015

The T406 engine development is discussed. The T406 is a 6000 horsepower class turboshaft, front drive, free turbine engine being developed under U.S. Navy contract to power the V-22 Osprey V/STOL aircraft. The V-22 is a subsonic airplane which uses tiltrotor technology to achieve V/STOL capabilities. The engine FSD program began in May of 1986 and will continue until May 1992.
A comprehensive engine description is given. The power/engine weight capability and growth potential make this engine the starting point for many future application.
Relationship Between Feedstock Characteristics and Erosivity of FBC Bed Materials
Authors: Levy Alan V. , Wang B. Q. , Geng G. Q. 
Published: March 2015

The erosion-corrosion (E-C) metal wastage mechanisms and rates that occur in 1018 plain carbon steel used in tubular heat exchangers of fluid bed combustors (FBC) are discussed. The characteristics of FBC bed material erodent particles such as composition, shape, size and strength were found to have a major effect on the surface degradation mechanisms and rates which occurred. A total of sixteen different bed material particles from ten different FBCs were tested. It was determined that when the particles were strong enough to not shatter when they impacted the steel’s surface, their shape and composition were the most important factors in determining their erosivity.
The relative amounts of SiO2, CaO, CaCO3, CaSO4, and alkali compounds in the bed materials were related to the metal wastage by using laboratory mixtures of the compounds as erodents. The ratio of SiO2 to CaO and CaCO3 was especially important in determining the erosivity of the bed materials. It was found that increasing this ratio increased the metal wastage. A sharp transition ratio occurred on either side of which the metal wastages were linear. The slope of the linear curve was low for the lower sand content mixtures and higher for higher sand content mixtures. The transition ratio required a higher CaO content for higher velocity particles.
Experimental Performance of a Heat Flux Microsensor
Authors: Hager J. M. , Simmons S. , Smith D. , Onishi S. , Langley L. W. , Diller T. E. 
Published: March 2015

The performance characteristics of a heat flux microsensor have been measured and analyzed. This is a new heat flux gage system that is made using microfabrication techniques. The gages are small, have high frequency response, can measure very high heat flux, and output a voltage directly proportional to the heat flux. Each gage consists of a thin thermal resistance layer sandwiched between many thermocouple pairs forming a differential thermopile. Because the gage is made directly on the measurement surface and the total thickness is less than 2µm, the presence of the gage contributes negligible flow and thermal disruption. The active surface area of the gage is 3 mm by 4 mm, with the leads attached outside this area to relay the surface heat flux and temperature signals.
Gages were made and tested on glass and silicon substrates. The steady and unsteady response was measured experimentally and compared with analytical predictions. The analysis was performed using a one-dimensional, transient, finite-difference model of the six layers comprising the gage plus the substrate. Steady-state calibrations were done on a convection heat transfer apparatus and the transient response was measured to step changes of the imposed radiative flux. As an example of the potential capabilities, the time-resolved heat flux was measured at a stagnation point with imposed freestream turbulence. A hot-film probe placed outside the boundary layer was used to provide a simultaneous signal showing the corresponding turbulent velocity fluctuations.
Considerations for the Use of Variable Geometry in Gas Turbines
Authors: Roy-Aikins J. E. A. 
Published: March 2015

The loss of performance of a gas turbine at off-design is primarily due to the rapid drop of the major cycle performance variables with decrease in output, and this may be aggravated by poor component performance. Postulated propulsion demands require that future engines attain performances much more advanced than those of the present day. The specific nature of the improvement in performance will depend on engine duty, but it is expected that the improvement will include higher power loadings and better response, in addition to better fuel burn characteristics.
Innovative design and advanced materials and structures will play key roles in bringing about a revolution in gas turbine technology, but these will have to be accompanied by novel control methods which can influence the position of the engine operating point. The latter may require the use of variable geometry in one or more gas path components to improve the internal matching of a component or to re-match the engine cycle such that the component operating point and/or the primary cycle performance variables are re-optimized or controlled with changing operating conditions. This paper examines how variable geometry could be used to improve the off-design performance of gas turbines.
RB211 Development and Experience With TransCanada Pipelines
Authors: Handy P. J. , Cooke L. A. , Pethrick D. J. 
Published: March 2015

This paper presents a brief history of RB211 operation from initial use in 1974 to present day tracing progressive uprating of original units from 22,000 horsepower to today’s 35,000 horsepower installations.
Problems associated with continuous operation are identified and the solutions discussed.
The maintenance philosophy that has evolved at TransCanada PipeLines to meet specific operational requirements is described, as well as maintenance techniques jointly developed to carry out the program. The merits of an Operator staffed repair base are described. TCPL’s RB211 operating costs per fired hour on a historical basis are summarized.
RB211 performance retention on the TCPL system is described, along with methods and modifications used to minimize or recover performance deterioration.
Finally, future trends in condition monitoring, modular maintenance, and future upgrade possibilities of older standards of the RB211 are discussed.
‘Recycling’ of Gas Turbines From Obsolete Aircraft
Authors: Morquillas Jose M. , Pilidis Pericles 
Published: March 2015

This paper examines the utilisation of aero gas turbines fitted to aircraft which are close to the end of their useful lives. When the aircraft are scrapped the engines can be removed, modified and employed for land or sea applications. The engine chosen as a possible candidate for ‘recycling’ is a two spool bypass engine.
A performance analysis has been carried out, which indicates that this scheme can yield good levels of output and efficiency.
Preliminary examinations indicate that there are economic advantages in converting these engines for other uses. Two possible conversions are examined: one for a pure industrial engine, and one as the gas side of a combined cycle power plant. The results obtained from this feasibility analysis appear attractive; the anticipated cost of purchasing and conversion is predicted to be significantly lower than purchasing new equipment.
Fatigue Strength Enhancement Using Shape Memory Alloy Bushings
Authors: Buchanan Edward R. , Celin Regina B. 
Published: March 2015

In recent years, there have been a number of failures of aircraft engine and structural components which are believed to have resulted from the accumulation of fatigue damage. The treatment of such damage is therefore of great significance from the standpoints of increased reliability and extended usage.
This paper presents the initial results of a program to evaluate a new process for the repair of fatigue-damaged aircraft engine components. In this process, the fatigue-damaged area is drilled out and replaced with a bushing manufactured from a new class of material called a ‘shape memory’ alloy. This material has the capability to expand in place following insertion, thus placing the surrounding material into compression.
A significant improvement in low cycle fatigue life was observed at 288°C in Ti-6Al-4V specimens treated with the above technique. The degree of improvement is about twice that which was obtained with a mechanical cold expansion technique used commercially to extend fatigue life. The degree of improvement of the subject process is greater at high numbers of cycles than at low numbers of cycles.
The subject project was funded as a Phase I Small Business Innovation Research award administered by the U.S. Naval Air Propulsion Center. Additional work in this area is planned which will a) identify the process parameters which will optimize the properties of shape memory alloy bushings, b) define the properties of shape memory alloy bushings over a wide range of temperature and loading conditions, and c) evaluate the effect in actual turbine engine hardware in a simulated engine environment.
Accelerated Mission Tests and Reliability Improvement of F3-30 Engine
Authors: Yanagihara Hideaki , Tateno Akira 
Published: March 2015

F3-30 is the low-bypass-ratio turbofan engine which has been developed to power the T-4 intermediate trainer for the Japan Air Self Defence Force (JASDF). The qualification tests of the engine were successfully completed in March, 1986, and the actual field service was started in September, 1988.
Before the start of the actual use, accelerated mission tests (AMT) were conducted for the purpose of finding deficiencies which would occur in the actual mission usage, and verifying the time between overhaul (TBO) of the initial service.
This paper describes the test method, the results, and the evaluation for them. Also it presents current status and basic ideas for the future reliability improvement of the F3-30 engine.