Combustor Rebuild Effects on Gas Turbine Performance

Author(s):  
J. D. MacLeod ◽  
B. Barry

The Institute for Aerospace Research of the National Research Council of Canada (NRCC), has established a program for the evaluation of component deterioration on gas turbine engine performance. The effort is aimed at investigating the effects of typical in-service faults on the performance characteristics of each individual engine component. As part of this project, a study of the effects of combustor rebuild tolerances on overall engine performance was undertaken. This study investigated the range of performance changes that might be expected for simply disassembling and reassembling the combustor module of a gas turbine engine, and how these changes would influence the results of any component modification testing. To evaluate the effects of rebuilding the combustor on the performance of a single spool engine, such as an Allison T56 turboprop engine, a series of three rebuilds was carried out. This study was performed in a similar way to two previous NRCC studies on the effects of compressor and turbine rebuilding. While the compressor and turbine rebuild studies found performance changes in the order of I% on various engine parameters, the effects of rebuilding the combustor have proven to be of similar magnitude. Based on the results of the combustor rebuild study, new methods to improve the assurance of the best possible tolerances during the rebuild process are currently being addressed. This paper describes the project objectives, the experimental installation, and the results of the performance evaluations. Discussed are performance variations due to combustor rebuilds on engine performance characteristics. As the performance changes were significant, a rigorous measurement uncertainty analysis is included.

Author(s):  
J. D. MacLeod ◽  
B. Drbanski

The Engine Laboratory of the National Research Council of Canada (NRCC), with the assistance of Standard Aero Ltd., has established a program for the evaluation of component deterioration on gas turbine engine performance. As part of this project, a study of the effects of turbine rebuild tolerances on overall engine performance was undertaken. This study investigated the range of performance changes that might be expected for simply disassembling and reassembling the turbine module of a gas turbine engine, and how these changes would influence the results of the component fault implantation program. To evaluate the effects of rebuilding the turbine on the performance of a single spool engine, such as Allison T56 turboprop engine, a series of three rebuilds were carried out. This study was performed in a similar way to a previous NRCC study on the effects of compressor rebuilding. While the compressor rebuild study had found performance changes in the order of 1% on various engine parameters, the effects of rebuilding the turbine have proven to be even more significant. Based on the results of the turbine rebuild study, new methods to improve the assurance of the best possible tolerances during the rebuild process are currently being addressed. This paper describes the project objectives, the experimental installation, and the results of the performance evaluations. Discussed are performance variations due to turbine rebuilds on engine performance characteristics. As the performance changes were significant, a rigorous measurement uncertainty analysis is included.


1992 ◽  
Vol 114 (2) ◽  
pp. 174-179 ◽  
Author(s):  
J. D. MacLeod ◽  
V. Taylor ◽  
J. C. G. Laflamme

Under the sponsorship of the Canadian Department of National Defence, the Engine Laboratory of the National Research Council of Canada (NRCC) has established a program for the evaluation of component deterioration on gas turbine engine performance. The effect is aimed at investigating the effects of typical in-service faults on the performance characteristics of each individual engine component. The objective of the program is the development of a generalized fault library, which will be used with fault identification techniques in the field, to reduce unscheduled maintenance. To evaluate the effects of implanted faults on the performance of a single spool engine, such as an Allison T56 turboprop engine, a series of faulted parts were installed. For this paper the following faults were analyzed: (a) first-stage turbine nozzle erosion damage; (b) first-stage turbine rotor blade untwist; (c) compressor seal wear; (d) first and second-stage compressor blade tip clearance increase. This paper describes the project objectives, the experimental installation, and the results of the fault implantation on engine performance. Discussed are performance variations on both engine and component characteristics. As the performance changes were significant, a rigorous measurement uncertainty analysis is included.


Author(s):  
J. D. MacLeod ◽  
V. Taylor ◽  
J. C. G. Laflamme

Under the sponsorship of the Canadian Department of National Defence, the Engine Laboratory of the National Research Council of Canada (NRCC) has established a program for the evaluation of component deterioration on gas turbine engine performance. The effort is aimed at investigating the effects of typical in-service faults on the performance characteristics of each individual engine component. The objective of the program is the development of a generalized fault library which will be used with fault identification techniques in the field, to reduce unscheduled maintenance. To evaluate the effects of implanted faults on the performance of a single spool engine, such as an Allison T56 turboprop engine, a series of faulted parts were installed. For this paper the following faults were analyzed: a) 1st stage turbine nozzle erosion damage, b) 1st stage turbine rotor blade untwist, c) compressor seal wear, d) 1st and 2nd stage compressor blade tip clearance increase. This paper describes the project objectives, the experimental installation, and the results of the fault implantation on engine performance. Discussed are performance variations on both engine and component characteristics. As the performance changes were significant, a rigorous measurement uncertainty analysis is included.


Author(s):  
J. D. MacLeod ◽  
W. Grabe

The Machinery and Engine Technology (MET) Program of the National Research Council of Canada (NRCC) has established a program for the evaluation of sensors to measure gas turbine engine performance accurately. The precise measurement of fuel flow is an essential part of steady-state gas turbine performance assessment. Prompted by an international engine testing and information exchange program, and a mandate to improve all aspects of gas turbine performance evaluation, the MET Laboratory has critically examined two types of fuel flowmeters, Coriolis and turbine. The two flowmeter types are different in that the Coriolis flowmeter measures mass flow directly, while the turbine flowmeter measures volumetric flow, which must be converted to mass flow for conventional performance analysis. The direct measurement of mass flow, using a Coriolis flowmeter, has many advantages in field testing of gas turbines, because it reduces the risk of errors resulting from the conversion process. Turbine flowmeters, on the other hand, have been regarded as an industry standard because they are compact, rugged, reliable, and relatively inexpensive. This paper describes the project objectives, the experimental installation, and the results of the comparison of the Coriolis and turbine type flowmeters in steady-state performance testing. Discussed are variations between the two types of flowmeters due to fuel characteristics, fuel handling equipment, acoustic and vibration interference and installation effects. Also included in this paper are estimations of measurement uncertainties for both types of flowmeters. Results indicate that the agreement between Coriolis and turbine type flowmeters is good over the entire steady-state operating range of a typical gas turbine engine. In some cases the repeatability of the Coriolis flowmeter is better than the manufacturers specification. Even a significant variation in fuel density (10%), and viscosity (300%), did not appear to compromise the ability of the Coriolis flowmeter to match the performance of the turbine flowmeter.


Author(s):  
V. Pachidis ◽  
P. Pilidis ◽  
I. Li

The performance analysis of modern gas turbine engine systems has led industry to the development of sophisticated gas turbine performance simulation tools and the utilization of skilled operators who must possess the ability to balance environmental, performance and economic requirements. Academic institutions, in their training of potential gas turbine performance engineers have to be able to meet these new challenges, at least at a postgraduate level. This paper describes in detail the “Gas Turbine Performance Simulation” module of the “Thermal Power” MSc course at Cranfield University in the UK, and particularly its practical content. This covers a laboratory test of a small Auxiliary Power Unit (APU) gas turbine engine, the simulation of the ‘clean’ engine performance using a sophisticated gas turbine performance simulation tool, as well as the simulation of the degraded performance of the engine. Through this exercise students are expected to gain a basic understanding of compressor and turbine operation, gain experience in gas turbine engine testing and test data collection and assessment, develop a clear, analytical approach to gas turbine performance simulation issues, improve their technical communication skills and finally gain experience in writing a proper technical report.


1991 ◽  
Vol 113 (4) ◽  
pp. 530-534 ◽  
Author(s):  
J. D. MacLeod ◽  
J. C. G. Laflamme

In an attempt to increase the time between maintenance actions and to improve performance retention of turboprop engines installed in transport and maritime patrol aircraft, the Canadian Department of National Defence is evaluating an erosion and corrosion-resistant blade coating, for use on compressors. As coatings could appreciably alter engine performance by virtue of their application thickness and surface quality, the National Research Council of Canada was asked to quantify any performance changes that could occur. A project was initiated, utilizing a new Allison T56 turboprop engine, to assess not only the performance changes resulting from the coating, but also those from dismantling and reassembling the compressor, since the compressor must be completely disassembled to apply the coating. This paper describes the project objectives, the experimental installation, and the measured effects of the coating application on compressor performance. Performance variations due to compressor rebuilds on both engine and compressor characteristics are discussed. As the performance changes were small, a rigorous measurement uncertainty analysis is included. The coating application process and the affected overhaul procedures are examined. The results of the pre- and postcoating compressor testing are presented, with a discussion of the impact on engine performance.


1995 ◽  
Vol 117 (1) ◽  
pp. 132-137 ◽  
Author(s):  
J. D. MacLeod ◽  
W. Grabe

The Machinery and Engine Technology (MET) Program of the National Research Council of Canada (NRCC) has established a program for the evaluation of sensors to measure gas turbine engine performance accurately. The precise measurement of fuel flow is an essential part of steady-state gas turbine performance assessment. Prompted by an international engine testing and information exchange program, and a mandate to improve all aspects of gas turbine performance evaluation, the MET Laboratory has critically examined two types of fuel flowmeters, Coriolis and turbine. The two flowmeter types are different in that the Coriolis flowmeter measures mass flow directly, while the turbine flowmeter measures volumetric flow, which must be converted to mass flow for conventional performance analysis. The direct measurement of mass flow, using a Coriolis flowmeter, has many advantages in field testing of gas turbines, because it reduces the risk of errors resulting from the conversion process. Turbine flowmeters, on the other hand, have been regarded as an industry standard because they are compact, rugged, reliable, and relatively inexpensive. This paper describes the project objectives, the experimental installation, and the results of the comparison of the Coriolis and turbine-type flowmeters in steady-state performance testing. Discussed are variations between the two types of flowmeters due to fuel characteristics, fuel handling equipment, acoustic and vibration interference, and installation effects. Also included in this paper are estimations of measurement uncertainties for both types of flowmeter. Results indicate that the agreement between Coriolis and turbine-type flowmeters is good over the entire steady-state operating range of a typical gas turbine engine. In some cases the repeatability of the Coriolis flowmeter is better than the manufacturer’s specification. Even a significant variation in fuel density (10 percent), and viscosity (300 percent) did not appear to compromise the ability of the Coriolis flowmeter to match the performance of the turbine flowmeter.


Author(s):  
Peter D. Smout ◽  
Steven C. Cook

The determination of gas turbine engine performance relies heavily on intrusive rakes of pilot tubes and thermocouples for gas path pressure and temperature measurement. For over forty years, Kiel-shrouds mounted on the rake body leading edge have been used as the industry standard to de-sensitise the instrument to variations in flow incidence and velocity. This results in a complex rake design which is expensive to manufacture, susceptible to mechanical damage, and difficult to repair. This paper describes an exercise aimed at radically reducing rake manufacture and repair costs. A novel ’common cavity rake’ (CCR) design is presented where the pressure and/or temperature sensors are housed in a single slot let into the rake leading edge. Aerodynamic calibration data is included to show that the performance of the CCR design under uniform flow conditions and in an imposed total pressure gradient is equivalent to that of a conventional Kiel-shrouded rake.


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