Thermal accumulation effects modelling of investigate radial shaft seal wear and lubrication transition mechanism

A radial shaft seal (RSS) model is established to reveal mixed thermal lubrication (MTL) and wear performance at speeds ranging from 3000 r/min to 7000 r/min. The model takes into account the initial temperatures of the oil medium and the running time of the RSS to investigate the transition limit of lubrication. Then a thermal fluid-solid method was developed to simulate the lubrication performance of RSS, which shows lubrication transition boundaries through rough micro convex bodies for wear deformation. The RSS deforms wedge-shaped during the wear process and a localized fluid pressure is created on the convex bodies. Considering the wear deformation of the convex bodies due to the wedge effect, the micro performance of the RSS can fully describe the mechanism of the leakage rate. As the dynamic pressure decreases and the leakage rate increases with the temperature of the medium, the RSS lubrication gradually transitions from MTL to EHL. Thus, the initial medium temperature should be considered to maintain the RSS under the mixed lubrication regime with low friction.