Influence of contact friction on static characteristics of multileaf bump foil bearing

Abstract

In order to reveal the influence mechanism of foil contact friction on the multi-leaf bump foil bearing performance, a deformation simulation model is established under the contact constraint of multi top foils and bump foils, and the analysis of the fluid-structure interaction is realized by combining with the Reynolds equation of compressible gas. The influence of the nonlinear variation of foil stiffness caused by contact friction on the static characteristics of the bearing under different bearing numbers is numerically analyzed. The results show: the foil stiffness increases nonlinearly with the foil deformation and presents the characteristic of circumferential non-uniformity. With the increase of the deformation of foil, the influence of friction coefficient on the foil stiffness is more significant. Within the parameters studied in this paper, the friction coefficient increases from 0 to 0.5, the bearing capacity increases first and then decreases when the bearing numbers is small; the bearing capacity increases monotonically when the bearing numbers is large, the higher the bearing numbers, the more significant the growth rate. The attitude angle increases with the increase of friction coefficient, and the bearing becomes more and more unstable. When the bearing numbers is large, we should pay more attention to the influence of friction on bearing performance. The computed model emphasizing nonlinear stiffness in this paper is close to the realities, and the results can provide guidance in the design of multi-leaf bump foil bearing.