Performances investigation and multi-objective optimization of gas foil bearings in hydrogen fuel cell vehicles

Gas foil bearings are crucial to guarantee stable operation and oil-free for centrifugal air compressors that pressure the air to the stack in hydrogen fuel cell vehicles. However, the load is smaller and the friction torque is larger. In this study, multi-objective optimization considering simultaneously both the higher load and lower friction torque is firstly performed to improve the reliability and decrease the energy consumption of the air compressor. The effects and contributions of the factors including rotation speed, nominal clearance, bump foil thickness, and bump pitch on two bearing performances are investigated by the Taguchi method and analysis of variance. The contributions of nominal clearance and rotation speed on the load are 68.82% and 18.62%, while the two factors on the contributions of friction torque are 66.48% and 17.62%, respectively. The optimal combination with the highest grey relational grade value of 0.7736 is obtained based on grey relational analysis. These findings can be used to guide the efficient operation and selection of the centrifugal air compressor in hydrogen energy vehicles.