Theoretical investigation of hybrid foil-magnetic bearings on operation mode and load sharing strategy

Abstract

This paper presents a theoretical investigation on operation mode and load sharing strategy of hybrid foil-magnetic bearings (HFMBs). According to the inherent characteristics of gas foil bearings (GFBs) and active magnetic bearings (AMBs), six possible work scopes are discussed to understand the operation mode of HFMBs. A numerical model coupling the calculations of the film pressure in GFBs and the magnetic forces in AMBs is conducted to predict the operation performance of HFMBs. The accuracy of the model is proved by comparing the predicted and tested friction torques. Analysis on the static and dynamic performance of HFMBs within three representative cases is conducted by varying the load sharing ratio. The dynamic supporting stiffness and operation position of HFMBs can be obviously enhanced by adjusting the operating mode and load sharing strategy. Results show that the direct stiffness and dynamic damping of HFMBs adopting hybrid mode are significantly higher than those adopting AMB or GFB independent mode.