Staic and Dynamic Characteristics of High-Speed, Stepped Thrust Gas-Film Bearings. Theoretical Analysis Considering Fluid Inertia Forces.

Abstract

Stepped thrust gas-film bearings are widely used for high-speed rotating machinery due to their simple structure and high load-carrying capacity. In such bearings, the fluid inertia forces may play an important role under high-speed operation conditions. This paper describes the effects of fluid inertia forces on the static and dynamic characteristics of stepped gas-film bearings. In the numerical analysis, the pressure distributions in the pocket and land regions are evaluated from the generalized Reynolds equation considering the centrifugal force. The pressure values at the step are calculated by considering the conservation of mechanical energy and the continuity of fluid flow in the pocket and land regions. Moreover, the dynamic response of the bearings subjected to impulsive and sinusoidal excitations are analyzed for different values of film thickness ratios. From the numerical results. the effects of fluid inertia on the static and dynamic characteristics of high-speed, stepped thrust gas-film bearings are clarified.