Effect of environmental pressure on dynamic characteristics of aerodynamic gas bearing of boost turbo expander

Abstract

Improvement of the environmental pressure of gas bearing can enhance the load capacity of dynamic gas bearing. This study analyzes the effect of environmental pressure on the dynamic characteristics of a bump foil gas aerodynamic bearing. Results show that an increase in the environmental pressure enhances the direct dynamic stiffness Kxx and Kyy and the direct dynamic damping Dxx and Dyy of gas film. The direct stiffness Kxx and Kyy and direct damping Dxx and Dyy of gas film increase with the increase of the environmental pressure of gas bearing. The load capacity of bearing is related to the direct stiffness of gas film. Therefore, the direct stiffness Kyy can be increased by increasing the environmental pressure of gas bearing, consequently improving the load capacity of the bearing.