Investigation on the dynamic response of aerostatic bearing-rotor system with different bearing gases

Abstract Due to their low friction and long lifespan, aerostatic bearings are widely used in high-speed cryogenic turbo expanders. Variations in bearing gas viscosity and density lead to differences in the static and dynamic characteristics of these bearings. In this study, a fluid-structure coupled model of the bearing-rotor system is established. The bearing lubricant equation and rotor motion equation are solved simultaneously to obtain the nonlinear dynamic response of the system. The findings reveal that the system exhibits rich nonlinear phenomena, indicating that the load capacity of helium bearings is greater than that of hydrogen and air bearings, while the stability of air bearings is superior to that of hydrogen and helium bearings.