Thermo-Elasto-Hydrodynamic analysis of gas foil bearing considering thermal effects

Abstract

Gas foil bearings (GFBs) face complex fluid-solid-thermal coupling challenges and pronounced thermal effects in ultra-high-speed and miniaturized machinery. This study investigates the thermo-elasto-hydrodynamic (TEHD) behavior of bump-type gas foil journal bearing under a steady rotating speed of ω = 1 × 10⁵ rpm during continuous loading process. A detailed three-dimensional numerical simulation integrating finite volume method (FVM) and the finite element method (FEM) is employed to get the coupled interactions between thermal effects, elastic deformation, and fluid lubrication. Results indicate that the increased load intensifies pressure-driven airflow variations, leading to suction and leakage effects at the axial bearing ends. The sharp rise in viscous-shearing heat in the gas film layer significantly elevates peak temperatures and creates non-uniform temperature distributions across the foil and shaft surfaces. This thermal imbalance results in substantial thermal deformation of the foils, with thermal expansion at the foils axial ends due to thermal stress release. The thermal deformation contributes 10∼25 % of the total deformation, while the intensity of thermal stresses comparable to that of elastic stress. This study is beneficial for accurately assessing bearing performance and provide valuable references for the design of GFBs.