Oil-free turbomachinery have emerged as one of the core technologies for the future green power generation systems as stand-alone systems or hybridized with high temperature fuel cells or solar systems. Oil-free technology allows compact, clean, and maintenance-free operation, and foil bearings are at the center of the technology. Since their first commercial applications in the air cycle machines and auxiliary power units in 1970s, significant improvement has been made to the computational models for rotordynamic behavior. However, many technical issues still remain unsolved or poorly understood, and one of them is thermal management. This paper presents transient three-dimensional thermohydrodynamic (3D THD) model of radial foil bearings to predict transient thermal behavior of the bearing-rotor system. The transient model involves transient energy equations applied to all the mechanical structures and gas film. The model was verified through extensive experimental measurements of transient thermal behavior of three-pad foil bearing for various cooling air pressures, external loads, and speeds. The predictions showed very good agreements with the experiments, and also the 3D THD model could predict potential thermal instability observed in the experimental measurements.
Issue Section:
Hydrodynamic Lubrication
Keywords:
foil bearing,
thermal instability,
oil-free,
transient thermohydrodynamic,
convection,
electric power generation,
fuel cells,
machine bearings,
rotors,
solar cells,
stability,
turbomachinery
Topics:
Bearings,
Cooling,
Rotors,
Temperature,
Transients (Dynamics),
Foil bearings,
Dynamic models
1.
Buck
, R.
, and Friedman
, S.
, 2007, “Solar-Assisted Small Solar Tower Trigeneration Systems
,” ASME J. Sol. Energy Eng.
0199-6231, 129
(4
), pp. 349
–354
.2.
Agnew
, G. D.
, Bozzolo
, M.
, Moritz
, R. R.
, and Berenyi
, S.
, 2005, “The Design and Integration of the Rolls-Royce Fuel Cell Systems 1MW SOFC
,” Proceedings of the ASME Turbo Expo 2005 Power for Land, Sea, and Air
, Reno-Tahoe, NV, Jun. 6–9, ASME Paper No. GT2005-69122.3.
Mueller
, F.
, Gaynor
, R.
, Auld
, A. E.
, Brouwer
, J.
, Jabbari
, F.
, and Samuelsen
, G. S.
, 2008, “Synergistic Integration of a Gas Turbine and Solid Oxide Fuel Cell for Improved Transient Capability
,” J. Power Sources
0378-7753, 176
(1
), pp. 229
–239
.4.
Tucker
, D.
, Lawson
, R.
, VanOsdol
, J.
, Kislear
, J.
, and Akinbobuyi
, A.
, 2006, “Examination of Ambient Pressure Effects on Hybrid Solid Oxide Fuel Cell Turbine System Operation Using Hardware Simulation
,” Turbo Expo 2006
, ASME Paper No. GT2006-91291.5.
Veyo
, S. E.
, Shockling
, L. A.
, Dederer
, J. T.
, Gillett
, J. E.
, and Lundberg
, W. L.
, 2002, “Tubular Solid Oxide Fuel Cell/Gas Turbine Hybrid Cycle Power Systems: Status
,” ASME J. Eng. Gas Turbines Power
0742-4795, 124
(4
), pp. 845
–849
.6.
Costamagna
, P.
, Magistri
, L.
, and Massardo
, A. F.
, 2001, “Design and Part-Load Performance of a Hybrid System Based on a Solid Oxide Fuel Cell Reactor and a Micro Gas Turbine
,” J. Power Sources
0378-7753, 96
(2
), pp. 352
–368
.7.
Ku
, C. -R.
, and Heshmat
, H.
, 1992, “Compliant Foil Bearing Structural Stiffness Analysis: Part I—Theoretical Model Including Strip and Variable Bump Foil Geometry
,” ASME J. Tribol.
0742-4787, 114
(2
), pp. 394
–400
.8.
Kim
, D.
, 2007, “Parametric Studies on Static and Dynamic Performance of Air Foil Bearings With Different Top Foil Geometries and Bump Stiffness Distributions
,” ASME J. Tribol.
0742-4787, 129
(2
), pp. 354
–364
.9.
Lee
, D.
, Kim
, Y.
, and Kim
, T.
, 2009, “The Dynamic Performance Analysis of Foil Journal Bearings Considering Coulomb Friction: Rotating Unbalance Response
,” STLE Tribol. Trans.
1040-2004, 52
(2
), pp. 146
–156
.10.
Le Lez
, S.
, Arghir
, M.
, and Frene
, J.
, 2007, “A New Bump-Type Foil Bearing Structure Analytical Model
,” ASME J. Eng. Gas Turbines Power
0742-4795, 129
(4
), pp. 1047
–1057
.11.
Lee
, D.
, and Kim
, D.
, 2010, “Five Degrees of Freedom Nonlinear Rotor Dynamics Model of a Rigid Rotor Supported by Multiple Airfoil Bearings
,” Proceedings of the Eighth IFToMM International Conference on Rotordynamics
, Seoul, Korea, Sept. 12–15.12.
Salehi
, M.
, Heshmat
, H.
, and Walton
, J. F.
, 2003, “On the Frictional Damping Characterization of Compliant Bump Foils
,” ASME J. Tribol.
0742-4787, 125
(4
), pp. 804
–813
.13.
Heshmat
, H.
, 1994, “Advancements in the Performance of Aerodynamic Foil Journal Bearings: High Speed and Load Capacity
,” ASME J. Tribol.
0742-4787, 116
(2
), pp. 287
–295
.14.
Heshmat
, H.
, Walton
, J. F.
, II, and Tomaszewski
, M. J.
, 2005, “Demonstration of a Turbojet Engine Using an Air Foil Bearing
,” Turbo Expo 2005
, ASME Paper No. GT2005-68404.15.
DellaCorte
, C.
, and Valco
, M. J.
, 2000, “Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbo-Machinery Applications
,” STLE Tribol. Trans.
1040-2004, 43
(4
), pp. 795
–801
.16.
Howard
, S. A.
, and DellaCorte
, C.
, 2001, “Dynamic Stiffness and Damping Characteristics of a High-Temperature Air Foil Journal Bearing
,” STLE Tribol. Trans.
1040-2004, 44
(4
), pp. 657
–663
.17.
Radil
, K.
, DellaCorte
, C.
, and Zeszotek
, M.
, 2007, “Thermal Management Techniques for Oil-Free Turbomachinery Systems
,” STLE Tribol. Trans.
1040-2004, 50
(3
), pp. 319
–327
.18.
Kumar
, M.
, and Kim
, D.
, 2008, “Parametric Studies on Dynamic Performance of Hybrid Air Foil Bearings
,” ASME J. Eng. Gas Turbines Power
0742-4795, 130
(6
), p. 062501
.19.
Kim
, D.
, and Park
, S.
, 2009, “Hydrostatic Air Foil Bearings: Analytical and Experimental Investigations
,” Tribol. Int.
0301-679X, 42
(3
), pp. 413
–425
.20.
Kim
, D.
, and Kumar
, M.
, 2009, “Load Capacity Measurements of Hydrostatic Bump Foil Bearing
,” Turbo Expo 2009
, Orlando, FL, ASME Paper No. GT2009-59286.21.
Kim
, D.
, and Lee
, D.
, 2010, “Design of Three-Pad Hybrid Air Foil Bearing and Experimental Investigation on Static Performance at Zero Running Speed
,” ASME J. Eng. Gas Turbines Power
0742-4795, 132
(12
), p. 122504
.22.
Lee
, D.
, and Kim
, D.
, 2011, “Design and Performance Prediction of Hybrid Air Foil Thrust Bearings
,” ASME J. Eng. Gas Turbines Power
0742-4795, 133
(4
), p. 042501
.23.
Dykas
, B.
, and Howard
, S. A.
, 2004, “Journal Design Considerations for Turbomachine Shafts Supported on Foil Air Bearings
,” STLE Tribol. Trans.
1040-2004, 47
(4
), pp. 508
–516
.24.
Radil
, K.
, and Zeszotek
, M.
, 2004, “An Experimental Investigation Into the Temperature Profile of a Compliant Foil Air Bearing
,” STLE Tribol. Trans.
1040-2004, 47
(4
), pp. 470
–479
.25.
Salehi
, M.
, Swanson
, E.
, and Heshmat
, H.
, 2001, “Thermal Features of Compliant Foil Bearings—Theory and Experiments
,” ASME J. Tribol.
0742-4787, 123
(3
), pp. 566
–571
.26.
Peng
, Z. C.
, and Khonsari
, M.
, 2006, “A Thermohydrodynamic Analysis of Foil Journal Bearings
,” ASME J. Tribol.
0742-4787, 128
(3
), pp. 534
–541
.27.
San Andrés
, L.
, and Kim
, T. H.
, 2009, “Thermohydrodynamic Analysis of Bump Type Gas Foil Bearings: A Model Anchored to Test Data
,” Turbo Expo 2009
, ASME Paper No. GT2009-59919.28.
Lee
, D.
, and Kim
, D.
, 2010, “Thermo-Hydrodynamic Analyses of Bump Air Foil Bearings With Detailed Thermal Model of Foil Structures and Rotor
,” ASME J. Tribol.
0742-4787, 132
(2
), p. 021704
.29.
Kim
, D.
, Lee
, D.
, Kim
, Y. C.
, and Ahn
, K. Y.
, 2010, “Comparison of Thermo-Hydrodynamic Characteristics of Airfoil Bearings With Different Top Foil Geometries
,” Proceedings of the Eighth IFToMM International Conference on Rotordynamics
, Seoul, Korea, Sept. 12–15.30.
Sim
, K.
, and Kim
, D.
, 2008, “Thermohydrodynamic Analysis of Compliant Flexure Pivot Tilting Pad Gas Bearings
,” ASME J. Eng. Gas Turbines Power
0742-4795, 130
(3
), p. 032502
.31.
Sim
, K.
, 2007, “Rotordynamic and Thermal Analyses of Compliant Flexure Pivot Tilting Pad Gas Bearings
,” Ph.D. thesis, Texas A&M University, College Station, TX.32.
Sadashiva
, R. P.
, 2010, “Experimental Investigation of Thermal Behaviour of Air Foil Bearings
,” MS thesis, The University of Texas at Arlington.33.
Incropera
, F. P.
, and Dewitt
, D. P.
, 2002, Introduction to Heat Transfer
, 4th Ed., Wiley
, New York
, pp. 516
–519
.34.
Lee
, D.
, and Kim
, D.
, 2010, “Three-Dimensional Thermo-Hydrodynamic Analyses of Rayleigh Step Air Foil Thrust Bearing With Radially Arranged Bump Foils
,” STLE Tribol. Trans.
1040-2004, in press.35.
Timoshenko
, S. P.
, and Goodier
, J. N.
, 1970, Theory of Elasticity
, McGraw-Hill
, New York
, pp. 80
–83
.Copyright © 2011
by American Society of Mechanical Engineers
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