Thermo-elasto-hydrodynamic analysis of a specific multi-layer gas foil thrust bearing under thermal-fluid–solid coupling
Qi-hong Gao, Wenjing Sun, Jingzhou ZHANG
Abstract
Gas foil bearing faces severe and complex thermal-fluid-solid coupling issues when in ultra-high speed and miniaturized impeller machineries. In this study, a Thermo-Elasto-Hydrodynamic (TEHD) analysis of a specific multi-layer gas foil thrust bearing on the continuous loading process within a steady rotational speed is numerically investigated by a three-dimensional thermal-fluid-solid coupling method. Results indicate that the multi-layer foil exhibits nonlinear overall stiffness, with the thrust bottom foil serving as the primary elastic deformation structure, while the thrust top foil maintains a well-defined aerodynamic shape during a loading process, which helps reduce frictional damage and achieve an adequate loading capacity. For low loads, the fluctuation of the gas film is extremely sensitive, and it weakens dramatically as the load increases. The viscous heating and friction torque exhibit a linear relationship with an increasing bearing load after a rapid growth. Depending on the exact stacking sequence and contact position of the multi-layer gas foil, the overlapping configuration allows for efficient transfer of viscous-shearing heat accumulated at the smallest air film through thermal conduction while providing elastic support. Due to the strong inhomogeneity of the viscous heat under varying loads, the temperature distribution on the top foil surface shows pronounced variations, while the difference between the peak and average temperatures of the thrust plate and top foil surfaces widens substantially with an increasing load.