Performance of Thrust Foil Bearings with Nonlinear Foil Stiffness Model

doi:10.3901/JME.2020.15.198

Abstract

Abstract: The test rig for measuring the stiffness of bump foil had been established. Based on the stiffness test of single bump foil, the nonlinear stiffness model of bump foil is derived by fitting the test data with MATLAB. The bump foil is meshed according to the structural characteristics of the sector bump foil and the stiffness of each node is given according to the area proportion of each node. By using the finite element method and the finite difference method, the gas Reynolds equation is solved coupled with film thickness equation and nonlinear stiffness model equation of the bump foil. The effects of the nonlinear stiffness characteristics of the bump foil on the static characteristics are studied. The constant stiffness model and the nonlinear stiffness model are simulated and analyzed, and the test results are compared to verify the reasonableness of the nonlinear stiffness of bump foil. By comparing the eccentricity calculated by the two models, it is found that the bump foil stiffness of the nonlinear stiffness model is smaller and the eccentricity is larger when the thrust foil bearing is under light load. In addition, the static characteristics of thrust bearing are predicted by the method of combining foil stiffness test and theory, which has certain engineering guiding significance.

Key words: air thrust foil bearing, nonlinear stiffness, load capacity, eccentricity, Reynolds equation

CLC Number:

V229
TH133

XU Fangcheng, HOU Liukai, WU Bin. Performance of Thrust Foil Bearings with Nonlinear Foil Stiffness Model[J]. Journal of Mechanical Engineering, 2020, 56(15): 198-206.

References

[1] LEE Y B,KIM T Y,KIM C H,et al. Thrust bump air foil bearings with variable axial load:Theoretical predictions and experiments[J]. Tribology Transactions,2011,54(6):902-910.
[2] AGRAWAL G L. Foil air/gas bearing technology-An overview[C]//ASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition,June 2-5,1997,Orlando,Florida,USA,1997.
[3] FU G,UNTAROIU A,SWANSON E. Effect of foil geometry on the static performance of thrust foil bearings[J]. Journal of Engineering for Gas Turbines and Power,2018,140(8):1-9.
[4] FENG K,KANEKO S. Analytical model of bump-type foil bearings using a link-spring structure and a finite-element shell model[J]. Journal of Tribology,2010,132(2):1-11.
[5] XU F C,KIM D,YAZDI B Z. Theoretical study of top foil sagging effect on the performance of air thrust foil bearing[C]//ASME Turbo Expo,June 13-17,2016,Seoul,South Korea,2016.
[6] FENG K,LIU L J,GUO Z Y,et al. Parametric study on static and dynamic characteristics of bump-type gas foil thrust bearing for oil-free turbomachinery[J]. Journal of Engineering Tribology,2016,230(8):944-961.
[7] LEE D,KIM D. Design and performance prediction of hybrid air foil thrust bearings[J]. Journal of Engineering for Gas Turbines and Power,2011,133(4):1-13.
[8] 徐方程,孙毅,刘占生,等. 基于箔片非线性刚度模型的气体箔片轴承静特性研究[J]. 机械工程学报,2016,52(21):56-62. XU Fangcheng,SUN Yi,LIU Zhansheng,et al. Static performance of gas foil bearings with nonlinear foil stiffness model[J]. Journal of Mechanical Engineering,2016,52(21):56-62.
[9] XU F C,KIM D. Dynamic performance of foil bearings with a quadratic stiffness model[J]. Neurocomputing,2016,216:666-671.
[10] WALOWIT J A,ANNO J N. Modern developments in lubrication mechanics[M]. London:Applied Science Publishers Ltd.,1975.
[11] HESHMAT H,WALOWIT J A,PINKUS O. Analysis of gas lubricated compliant thrust-bearings[J]. Journal of Lubrication Technology,1983,105(4):638-646.
[12] HESHMAT H,WALOWIT J A,PINKUS O. Analysis of gas-lubricated foil journal bearings[J]. Journal of Lubrication Technology,1983,105(4):647-655.
[13] ROGER K C R,HESHMAT H. Compliant foil bearing structural stiffness analysis:part I-Theoretical model including strip and variable bump foil geometry[J]. Journal of Tribology,1992,114(2):394-400.
[14] IORDANOFF I. Analysis of an aerodynamic compliant foil thrust bearing:Method for a rapid design[J]. Journal of Tribology,1999,121(4):816-822.
[15] HESHMAT C A,XU D S,HESHMAT H. Analysis of gas lubricated foil thrust bearings using coupled finite element and finite difference methods[J]. Journal of Tribology,2000,122(1):199-204.
[16] GAD A M,KANEKO S. A new structural stiffness model for bump-type foil bearings:Application to generation Ⅱ gas lubricated foil thrust bearing[J]. Journal of Tribology,2014,136(4):1-13.
[17] RUBIO D,ANDRÉS L S. Bump-type foil bearing structural stiffness:Experiments and predictions[J]. Journal of Engineering for Gas Turbines and Power,2004,128(3):653-660.
[18] CABLE T A,ANDRÉS L S. On the design,manufacture,and premature failure of a metal mesh foil thrust bearing-How concepts that work on paper,actually do not[J]. Journal of Engineering for Gas Turbines and Power,2018,140(12):1-13.
[19] KIM T H,PARK M S,LEE J,et al. Identification of dynamic characteristics of gas foil thrust bearings using base excitation[C]//ASME Turbo Expo,June 13-17,2016,Seoul,South Korea,2016.
[20] 徐方程,刘占生,张广辉,等. 气体止推箔片轴承试验台设计及试验[J]. 航空动力学报,2016,31(9):2298-2304. XU Fangcheng,LIU Zhansheng,ZHANG Guanghui,et al. Test rig design and experiment of gas thrust foil bearing[J]. Journal of Aerospace Power,2016,31(9):2298-2304.