A Fully Coupled Fluid-Structure-Interaction Model for Foil Gas Bearings

Foil gas bearings are self-acting, compliant-surface hydrodynamic bearings that usually use air or other process gas as their working fluid or lubricant. Foil gas bearings are made of one or more bump foils, which are compliant surfaces of corrugated metal, and one or more layers of top foil. Because foil gas bearing performance parameters, such as load capacity, are dominated by foil material and foil geometric designs, numerical models have been developed to predict the bearing’s performance based on these characteristics. However, previous models often simplify bump foil as elastic foundation with constant stiffness and neglect top foil altogether. Further, they typically use the Reynolds equation to simplify the fluid solution. In this study, ANSYS software is used to build a 3D, fully-coupled, fluid-structure-interaction model for a foil gas bearing to predict key performance parameters such as load capacity and journal attitude angle. The model’s results show good agreement with previously published test data. This not only demonstrates the feasibility of 3D fully coupled fluid-structure-interaction model for a conventional foil bearing using commercial codes, but also shows modeling capability for future generations of foil gas bearing.