Analysis of the effect of floating bearing clearance on the dynamic characteristics of turbocharger rotors

Abstract To investigate the effects of inner and outer clearances of the floating bearing on the rotor dynamics of a turbocharger, a dynamic model of the rotor system was developed using the JP48A double-row full-floating bearing as the research subject in DyRoBes software. The effects of inner and outer clearances on lubricant film stiffness, damping, system critical speed, and rotor vibration were analyzed and calculated. The results indicate that increasing the inner and outer clearances of the floating bearing reduces lubricant film stiffness while increasing damping. This leads to a significant decrease in the rotor system’s critical speed and an increase in vibration amplitude. Notably, the maximum vibration amplitude of the turbine rotor does not coincide with the critical speed location.