Influence of dynamic change of radial clearance on flow and thermal characteristics of full ceramic angular contact ball bearing

This paper aims to investigate the change in radial clearance. The study focuses on the influence of this change on the internal flow distribution and thermal characteristics of full ceramic angular contact ball bearing under oil-gas two-phase flow lubrication. Using elastic theory to compute changes in radial clearance due to elastic deformation, centrifugal displacement, and thermal expansion. A theoretical model calculating the inner ring displacement and radial clearance values was established. Next, a numerical analysis model, based in two-phase flow lubrication theory, was used to analyze the flow field characteristics. Fluid-structure interaction techniques were used to assess the changing effects of radial clearance changes on the flow field and thermal behaviors within the bearing cavity. The accuracy of the simulation was verified by a bearing temperature rise test. The results indicate that the oil phase, primarily affected by centrifugal forces, tends to concentrate around the outer ring of the bearing. As the interference fit increases, the radial clearance diminishes, resulting in a lower oil phase volume fraction. A decrease in bearing temperature rise was observed with radial clearance increasing, showing that a larger radial clearance can mitigate the heat generated within the bearing.