The Influences of the Rotor Waviness on the Hydrodynamic Characteristics of Gas Porous Bearings With Mixed Computational Fluid Dynamics Boundary Conditions

Abstract

Manufacturing errors impacted the gas porous bearing's performance, particularly the waviness on the rotor surface that repeatedly squeezed the gas film during rotation. This study investigated the effects of waviness errors using a novel mixed computational fluid dynamics (CFD) boundary condition that combined steady circumferential motion with transient radial motion. The mixed boundary condition was verified against numerical results. A transient CFD model was developed for gas porous bearings with rotor surface waviness. The transient squeezing effects from the rotating waviness significantly influenced both the hydrostatic and hydrodynamic performance of the bearing. By implementing periodic sinusoidal waviness, the effects of eccentricity, waviness amplitude, waviness number, rotor speed, and supply pressure on the performances of the gas porous bearing were investigated.