Numerical analysis of aerodynamic lubricated double-decked protuberant foil thrust bearing

Abstract

Double-decked protuberant foil bearing is a type of foil bearing that uses two stacking-up layers of protuberant foils as supporting structure. In preliminary experiments, wear failure of foil thrust bearing occurs occasionally due to excessive axial load in the bearing. Further improvement of the bearing performance is necessary for its better engineering application. In this paper, a numerical model of this kind of foil bearing is applied to predict its static characteristics. Reynolds equation and Kirchhoff equation are coupled via successive iterations of film pressure and foil deformation. A parametric study is conducted to improve the static characteristics of the bearing, which is conducive to load capacity improvement. The load capacity of the bearing is represented by the bearing load with the given nominal film clearance. Due to point and surface contact between the foils, distribution of protuberances plays an important role in the stiffness distribution of the protuberant foil thrust bearing. Effect of radial location of protuberances on bearing load is analyzed. Furthermore, parametric studies with different foil thickness and diameter are conducted for further optimization. The results indicate that large unevenness of stiffness distribution will deteriorate its static characteristics. Through adjustment of the radial locations of protuberances, static performance of the double-decked protuberant foil thrust bearing can be improved prominently under different operating conditions.