The dynamic pressure effect of gas microbearings under high rotational speed

Abstract

A gas journal microbearing and the corresponding rotor-bearing system are studied both theoretically and experimentally for their application in the high-speed air compressor of fuel cell vehicles. The gas microbearing is proved to provide reliable support for the rotor, as it shows both static and dynamic pressure effects under the high operating speed of the on-board air compressor. In order to realize the corresponding theoretical analysis, a new UDF dynamic mesh program is internally developed, with which an original method of CFD transient simulation calculations is proposed. Using this method, the gas microbearing’s load-carrying capacity, stiffness and damping coefficients, and static equilibrium position are analyzed for various fluid fields and under different rotational speeds. Theoretical analysis and experimental tests are performed for the corresponding rotor-bearing system in a high-speed air compressor. The experimental result verifies the practicability of the bearings and agrees well with the simulation results, demonstrating the effectiveness and the high accuracy of the new simulation method using dynamic mesh.