Capabilities of Large Foil Bearings

2000 ◽  
Author(s):  
Erik E. Swanson ◽  
Hooshang Heshmat
Keyword(s):  
Gas Turbine ◽  
Thermal Performance ◽  
Experimental Program ◽  
Practical Application ◽  
Test Rig ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Compliant Surface ◽  
Foil Bearing ◽  
Engine Rotor

An experimental program was conducted on a large compliant surface foil bearing to document its performance. This large single pad foil bearing is 100 mm in diameter, and was operated at speeds of up to 30,000 RPM. Operation at 22,000 RPM with a measured load of 4190 N was also demonstrated. During coastdown runs from 30,000 RPM, maximum amplitudes of shaft vibration did not exceed 7.6 μm while passing through the two rigid shaft modes of the system. Thermal performance of the bearing was also in accord with previously documented foil bearings. This testing also demonstrates the practicality of scaling smaller foil bearing designs to the large bearings required for larger turbomachinery. To enhance the practical application of the results, the test rig shaft was designed to simulate a small gas turbine engine rotor.

The Application of Gas- and Oil-Lubricated Foil Bearings for the ERDA/Chrysler Automotive Gas Turbine Engine

1976 ◽  
Author(s):  
S. Gray ◽  
N. Sparks ◽  
J. McCormick
Keyword(s):  
Gas Turbine ◽  
Cost Savings ◽  
Turbine Rotor ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Rotor Bearing ◽  
Dynamic Simulator ◽  
And Performance ◽  
Engine Rotor

A design study has been made of a resilient hydrodynamic foil bearing support system for a 58,500-rpm automotive gas turbine rotor utilizing an air-lubricated journal bearing at the hot turbine end and an oil-lubricated journal and thrust bearing at the compressor end. The paper includes a review of earlier engine rotor/bearing systems and lists the potential advantages of the foil bearings. Design analysis of the bearings and rotordynamics is given including critical speeds, rotor unbalance response, bearing performance, and temperature distributions to confirm the feasibility. The study shows that potential improvements to the overall system in terms of cost savings, reliability, and performance are possible. Full-scale dynamic simulator testing of the rotor bearing system as designed is in progress.

Test Experience With Turbine-End Foil Bearing Equipped Gas Turbine Engines

1983 ◽  
Author(s):  
F. J. Suriano ◽  
R. D. Dayton ◽  
Fred G. Woessner
Keyword(s):  
Gas Turbine ◽  
Thermal Environment ◽  
Full Range ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Engine Test ◽  
Gas Generator ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Foil Bearing

The Garrett Turbine Engine Company, a Division of the Garrett Corporation, authorized under Air Force Contract F33615-78-C-2044 and Navy Contract N00140-79-C-1294, has been conducting development work on the application of gas-lubricated hydrodynamic journal foil bearings to the turbine end of gas turbine engines. Program efforts are directed at providing the technology base necessary to utilize high-temperature foil bearings in future gas turbine engines. The main thrust of these programs was to incorporate the designed bearings, developed in test rigs, into test engines for evaluation of bearing and rotor system performance. The engine test programs included a full range of operational tests; engine thermal environment, endurance, start/stops, attitude, environmental temperatures and pressures, and simulated maneuver bearing loadings. An 88.9 mm (3.5-inch) diameter journal foil bearing, operating at 4063 RAD/SEC (38,800 rpm), has undergone test in a Garrett GTCP165 auxiliary power unit. A 44.4 mm (1.75-inch) diameter journal foil bearing, operating at 6545 RAD/SEC (62,500 rpm) has undergone test in the gas generator of the Garrett Model JFS190. This paper describes the engine test experience with these bearings.

The Emergence of Compliant Foil Bearing and Seal Technologies in Support of 21st Century Compressors and Turbine Engines

2010 ◽  
Author(s):  
Hooshang Heshmat ◽  
Zhaohui Ren ◽  
Andrew Hunsberger ◽  
James Walton ◽  
Said Jahanmir
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
High Efficiency ◽  
Positive Impact ◽  
Experimental Program ◽  
Operating Efficiency ◽  
Turbine Engines ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Face Seals

For energy independence to become a reality, whether through the more effective use of US natural resources such as natural gas or through the continued development of the hydrogen economy, efficient and reliable large-scale compressors are needed to enhance the existing pipeline infrastructure that moves energy storing gases from production sites to end user locations. Oil-free, non-contacting seal and bearing technologies are critical to the successful development of new high efficiency and power dense compressors. Similarly with increasing emphasis on energy conservation, power and propulsion gas turbine engines will require advanced low leakage seals and may take advantage of efficiencies offered by compliant foil gas bearings. When properly applied these oil-free, non contacting technologies will have a positive impact on the operating efficiency and life of compressor and gas turbine engine systems. The overall objective of this paper is to present recent advances in compliant foil bearings and seals that make them attractive for a wide array of systems. The paper documents the design approach that includes analytical trade off studies to establish overall requirements followed by an experimental program to demonstrate the ability of the identified foil technology to meet the machine requirements. A summary of advancements in foil bearing load carrying capacity, size scaling from 6 mm to 150 mm in diameter, the ability to operate under shock loads greater than 40 g as well as under steady side loads with two different gases and finally the ability to operate at temperatures greater than 750 C will be presented. Data will also be presented showing the application of foil bearings to several different machines. Similarly, results from design, fabrication and testing of compliant foil radial and axial face seals will be discussed. Data from axial face seals testing at differential pressures, surface velocities, and normal loads greater than 675 kPa, 350 m/s, and 1100 N respectively will be presented to demonstrate non-contacting performance. Results of subcomponent testing will also be presented to demonstrate the capability of the face seal to accommodate axial excursions of up to 3.8 mm. Compliant foil radial seal testing in sizes ranging from approximately 60 to 215 mm in diameter under differential pressures to 690 kPa and surface velocities to 340 m/s will be presented and compared to prediction. The culmination of the work presented supports the application of compliant foil bearings and seals in a wide array of advanced machinery.

Operation of a Mesoscopic Gas Turbine Simulator at Speeds in Excess of 700,000 rpm on Foil Bearings

2004 ◽  
Author(s):  
Mohsen Salehi ◽  
Hooshang Heshmat ◽  
James F. Walton ◽  
Michael Tomaszewski
Keyword(s):  
Gas Turbine ◽  
Air Bearings ◽  
Turbine Engine ◽  
Power Generators ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Single Piece ◽  
Measurement And Analysis ◽  
Successful Testing ◽  
Bearing System

A small mesoscopic gas turbine engine (MGTE) simulator was tested at speeds over 700,000 rpm. The MGTE was operated with specially designed miniature compliant foil journal and thrust air bearings. The operation of the simulator rotor and foil bearing system is a precursor to development of turbine powered micro aerial vehicles and mesoscopic power generators. The foil bearings use a new fabrication technology in which each bearing is split. This feature permits the use of these bearings in highly advanced engines where single piece ceramic rotors may be required. The simulator weighed 56 grams (including the 9 gram rotor) and included two non-aerodynamic wheels to simulate the compressor and turbine wheels. Each compliant foil journal bearing had a diameter of 6 mm and was located equidistant from each end of the rotor. Experimental work included operation of the simulator at speeds above 700,000 rpm and at several different orientations including having the spin axis vertical. Results of the rotor bearing system dynamics are presented along with experimentally measured natural frequencies at many operating speeds. Good correlation between measurement and analysis is observed indicating the scalability of the analysis tools and hardware used. The rotor was very stable and well controlled throughout all testing conducted. Based on this successful testing it is expected that the goal of operating the rotor at speeds exceeding 1 million rpm will be achieved.

Operation of a Mesoscopic Gas Turbine Simulator at Speeds in Excess of 700,000rpm on Foil Bearings

2004 ◽  
Vol 129 (1) ◽  
pp. 170-176 ◽  
Author(s):  
Mohsen Salehi ◽  
Hooshang Heshmat ◽  
James F. Walton ◽  
Michael Tomaszewski
Keyword(s):  
Gas Turbine ◽  
Air Bearings ◽  
Turbine Engine ◽  
Power Generators ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Single Piece ◽  
Measurement And Analysis ◽  
Successful Testing ◽  
Bearing System

A small mesoscopic gas turbine engine (MGTE) simulator was tested at speeds over 700,000rpm. The MGTE was operated with specially designed miniature compliant foil journal and thrust air bearings. The operation of the simulator rotor and foil bearing system is a precursor to development of turbine powered micro-aerial vehicles and mesoscopic power generators. The foil bearings use a new fabrication technology in which each bearing is split. This feature permits the use of these bearings in highly advanced engines where single piece ceramic rotors may be required. The simulator weighed 56g (including the 9g rotor) and included two non-aerodynamic wheels to simulate the compressor and turbine wheels. Each compliant foil journal bearing had a diameter of 6mm and was located equidistant from each end of the rotor. Experimental work included operation of the simulator at speeds above 700,000rpm and at several different orientations including having the spin axis vertical. Results of the rotor bearing system dynamics are presented along with experimentally measured natural frequencies at many operating speeds. Good correlation between measurement and analysis is observed indicating the scalability of the analysis tools and hardware used. The rotor was very stable and well controlled throughout all testing conducted. Based on this successful testing it is expected that the goal of operating the rotor at speeds exceeding 1 million rpm will be achieved.

Non-Linear Effects of Vibration in Gas Turbine Engines With Two or Three Rotors

2002 ◽  
Author(s):  
J. Pismenny ◽  
Y. Levy
Keyword(s):  
Complex System ◽  
Gas Turbine ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Practical Application ◽  
Turbine Engine ◽  
Non Linear ◽  
Linear Elements ◽  
Linear Effects ◽  
Linear Oscillation

The dependence of the vibration characteristics of gas turbine engines on the rotor speeds becomes highly complicated in engines with two and three rotors, both because of the simultaneous dynamic action of the multiple rotors and the ambiguous relationships between their speeds. In this paper, the gas turbine engine is analyzed in the context of the theory of non-linear oscillation — as a complex system comprising a large number of non-linear elements and multiple periodical forces of different frequencies (defined by the rotor speeds). This paper presents results, which indicate that the level of vibration can obtain critical values at certain relationships between the rotor speeds. As a practical application of this phenomena it is shown that the number of three-spool engines returns from the aircraft to the engine manufacturer, due to different kinds of malfunctions, for example due to activation of the “intensified vibration” alarm, may be approximately three times that of returns of analogous two-rotor engines.

Performance of a Foil-Magnetic Hybrid Bearing

2000 ◽  
Author(s):  
Erik E. Swanson ◽  
Hooshang Heshmat ◽  
James Walton
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Magnetic Bearing ◽  
Experimental Program ◽  
Turbine Engine ◽  
Foil Bearing ◽  
Speed Performance ◽  
Hybrid Bearing ◽  
High Load Capacity ◽  
Bearing System

To meet the advanced bearing needs of modern turbomachinery, a hybrid foil-magnetic hybrid bearing system was designed, fabricated and tested in a test rig designed to simulate the rotor dynamics of a small gas turbine engine (31 kN to 53 kN thrust class). This oil-free bearing system combines the excellent low and zero-speed capabilities of the magnetic bearing with the high load capacity and high speed performance of the compliant foil bearing. An experimental program is described which documents the capabilities of the bearing system for sharing load during operation at up to 30,000 RPM and the foil bearing component’s ability to function as a back-up in case of magnetic bearing failure. At an operating speed of 22,000 RPM, loads exceeding 5300 N were carried by the system. This load sharing could be manipulated by an especially designed electronic control algorithm. In all tests, rotor excursions were small and stable. During deliberately staged magnetic bearing malfunctions, the foil bearing proved capable of supporting the rotor during continued operation at full load and speed, as well as allowing a safe rotor coast-down. The hybrid system tripled the load capacity of the magnetic bearing alone and can offer a significant reduction in total bearing weight compared to a comparable magnetic bearing.

Application of a Turbulent Jet Flame Flashback Propensity Model to a Commercial Gas Turbine Combustor

2016 ◽  
Author(s):  
Alireza Kalantari ◽  
Elliot Sullivan-Lewis ◽  
Vincent McDonell
Keyword(s):  
Gas Turbine ◽  
Equivalence Ratio ◽  
High Pressures ◽  
Design Tool ◽  
Test Rig ◽  
Preheat Temperature ◽  
High Hydrogen ◽  
Turbine Engine ◽  
Jet Flame ◽  
Micro Turbine

Because flashback is a key operability issue associated with low emission combustion of high hydrogen content fuels, design tools to predict flashback propensity are of interest. Such a design tool has been developed by the authors to predict boundary layer flashback using non-dimensional parameters. The tool accounts for the thermal coupling between the flame and burner rim and was derived using detailed studies carried out in a test rig at elevated temperature and pressure. The present work evaluates the applicability of the tool to a commercial 65 kW micro turbine generator (MTG). Two sets of data are evaluated. One set is obtained using the combustor, removed from the engine, which has been configured to operate like it does in the engine but at atmospheric pressure and various preheat temperatures. The second set of data is from a combustor operated as it normally would in the commercial engine. In both configurations, studies are carried out with various amounts of hydrogen added to either natural gas or carbon monoxide. The previously developed model is able to capture the measured flashback tendencies in both configurations. In addition, the model is used to interpret flashback phenomena at high pressures and temperatures in the context of the engine conditions. An increase in pressure for a given preheat temperature and velocity reduces the equivalence ratio at which flashback occurs and increases the tip temperature due to lower quenching distance. The dependency of the flashback propensity on the injector tip temperature is enhanced with an increase in pressure. The variation of critical velocity gradient with equivalence ratio for a constant preheat temperature is more pronounced at higher pressures. In summary, the model developed using the high pressure test rig is able to predict flashback tendencies for a commercial gas turbine engine and can thus serve as an effective design tool for identifying when flashback is likely to occur for a given geometry and condition.

scholarly journals A New Analysis Tool Assessment for Rotordynamic Modeling of Gas Foil Bearings

2010 ◽  
Author(s):  
Samuel A. Howard ◽  
Luis San Andre´s
Keyword(s):  
Power Loss ◽  
High Speed ◽  
Structural Deformation ◽  
Analysis Tool ◽  
Test Rig ◽  
Contributing Factors ◽  
Foil Bearings ◽  
Rotordynamic Coefficients ◽  
Foil Bearing ◽  
Analytical Tools

Gas foil bearings offer several advantages over traditional bearing types that make them attractive for use in high-speed turbomachinery. They can operate at very high temperatures, require no lubrication supply (oil pumps, seals, etc), exhibit very long life with no maintenance, and once operating airborne, have very low power loss. The use of gas foil bearings in high-speed turbomachinery has been accelerating in recent years, although the pace has been slow. One of the contributing factors to the slow growth has been a lack of analysis tools, benchmarked to measurements, to predict gas foil bearing behavior in rotating machinery. To address this shortcoming, NASA Glenn Research Center (GRC) has supported the development of analytical tools to predict gas foil bearing performance. One of the codes has the capability to predict rotordynamic coefficients, power loss, film thickness, structural deformation, and more. The current paper presents an assessment of the predictive capability of the code, named XLGFBTH©. A test rig at GRC is used as a simulated case study to compare rotordynamic analysis using output from the code to actual rotor response as measured in the test rig. The test rig rotor is supported on two gas foil journal bearings manufactured at GRC, with all pertinent geometry disclosed. The resulting comparison shows that the rotordynamic coefficients calculated using XLGFBTH© represent the dynamics of the system reasonably well, especially as they pertain to predicting critical speeds.

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