Thermal characteristics for bearing combined EHL theory with CFD method

In order to accurately predict the thermal characteristics of angular contact ball bearing in the transmission system under spray lubrication, the bearing thermal elastohydrodynamic lubrication (EHL) model was established, and the micro-contact interface load and friction coefficient between the raceway and ball were obtained. On the basis, heat generation was calculated by using the local generation. Computational fluid dynamics (CFD) method was used to establish a coupled oil-gas two-phase flow model for angular contact ball bearings, including the choice of turbulence model and fluid domain boundary conditions. Furthermore, fuel injection speed, nozzle position and gas fraction were analyzed. Results showed that the application of CFD method with accurate heat generation calculated by the thermal EHL theory could predict the optimal injection speed, the nozzle position and gas fraction of the bearing under various operating conditions, lubrication parameters and geometric parameters. When the injection speed was 5 m/s, the maximum temperature of the bearing chamber was decreased by 440% compared with other injection speeds. When the nozzle position was below the bearing axis, the maximum temperature of the bearing chamber decreased by 430% compared with other positions. When gas fraction was 15%, the maximum temperature of the bearing chamber was improved by 157% compared with other gas fraction.