Thermo-elasto-hydrodynamic analysis of gas foil bearings

This paper proposes a comprehensive model for thermo-elasto-hydrodynamic analysis of gas foil bearings. In contrast to many works that simplify the foil structure to a two-dimensional model, the top foil and bump foil are modeled using the shell elements to consider the three-dimensional configuration and axial variation in deflection. To more accurately predict the heat transferred from the gas film to the bump foil, the subambient pressure is allowed and a contact model is developed to consider the nonlinear contact/separation behavior of foil structure. Emphasis is put on the thermal submodels of the gas film, rotor, foil structure and bearing sleeve, where the energy equation and heat equations are numerically solved using the finite element method. The global temperatures of the bearing system are simultaneously obtained using a fully coupled method, enabling a computationally efficient and robust solution. The results reveal that the temperature distribution of gas film exhibits fluctuations due to the contacts between the top and bump foils, but the subambient pressure also causes separations between the foils near the trailing region. Additionally, parametric studies are conducted to explore the effects of the rotational speed and nominal clearance on the thermal performance of foil bearings.