Dynamic Characteristics of Gas Foil Bearing Based on Bump Foil Stiffness Test

doi:10.3901/JME.2015.21.057

Abstract

Abstract:

In order to study the bump stiffness and its effect on dynamic coefficients of foil bearing, a test rig is designed to measure the stiffness of bump foil. Two type of bump foil under fixed-fixed ends and fixed-free ends constraint conditions are both tested and the experimental results are compared with numerical results. Finally, based on the obtained bump foil stiffness, the dynamic coefficients of foil bearing are obtained by using perturbation method, and the effect of bump foil stiffness on these coefficients are studied. The results indicate that the fixed-fixed ends bump foil has 5 times greater stiffness per unit width than fixed-free ends bump foil, and with the increase of bump deflection, the stiffness of fixed-fixed ends bump foil is more nonlinear than the fixed-free ends bump foil, but the numerical results don’t show any same nonlinear feature except of the increase of stiffness value due to the structural friction coefficient. At last, the bearing stiffness and direct damping can be enlarged with the increase of bearing load while the other damping values decrease, and values of bearing dynamic coefficients using tested bump stiffness grow faster than using numerical bump foil stiffness due to the nonlinear stiffness features of bump foil.

Key words:

XU Fangcheng, ZHANG Wen, LIU Zhansheng.

Dynamic Characteristics of Gas Foil Bearing Based on Bump Foil Stiffness Test

[J]. Journal of Mechanical Engineering, 2015, 51(21): 57-64.

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