Critical speed analysis on high-speed foil bearing rotor of fuel cell air compressor

Based on the characteristic analysis of dynamic pressure gas bearing, the reliability analysis of high-speed rotors of fuel cell air compressors is carried out in this paper, which is of great significance for the study of the safety of automotive fuel cell systems. The calculation method of rotor critical speed is introduced, and its key role in the reliability analysis of the rotor system is analyzed. The dynamic pressure gas bearing used in the rotor system is calculated and analyzed, and its stiffness and damping changes with the speed are obtained. Based on the calculated bearing performance parameters, a 2D finite element model is built for the rotor system, and its critical speed and mode are analyzed. The modal analysis is carried out according to the 3D rotor system model, and the calculation accuracy of the 2D model is further verified by using the 3D model. The conclusion is drawn that the critical speed of the rotor system is far away from the working speed to ensure operation safety, and the construction of the accurate model can better simulate the actual dynamics of the rotor and help the structure optimization and adjustment in the design process to ensure the safety of the rotor operation.