Abstract:
In the present study, the static and dynamic characteristics of Generation II bump-type foil thrust bearings are investigated. For the static characteristics, a 2D compressible Reynolds equation containing effects of centrifugal forces is derived to model the fluid flow in the thin gas film. The compliance of the bearing is calculated using analytical structural stiffness model. The fluid flow equation is coupled to the structural stiffness model and the coupled fluid-structure interaction problem is solved iteratively to obtain the steady state characteristics of the bearing. For the dynamic characteristics, small perturbations method is used to obtain the linearized equations for the pressure components of dynamic force coefficients. The effects of rotation speed, ramp height, nominal film thickness, friction coefficients at bump foil interfaces, and bump foil stiffness on the static and dynamic characteristics of Generation II foil thrust bearings are thoroughly analyzed.