Composite thermal oil film lubrication model for hybrid journal bearings.

Hybrid journal bearings are crucial components in many equipment, such as nuclear reactor cooling pumps and hydraulic motors. However, there exists a significant challenge to understand the lubrication behaviors of hybrid bearings with multiple thermal effects at low-speed, heavy-load conditions. Therefore, a composite thermal lubrication model is proposed, which includes four thermal effects: edge suction heat, hydrostatic pressure loss heat, oil viscous friction heat, and asperity friction heat. The lubrication and contact model are modified by actual rough surfaces to evaluate friction heat accurately. The experiments from a homemade testing rig verify the model well. Friction and temperature characteristics of the hybrid bearing are obtained, and the influence of hydraulic pressure and speed on four types of heat are analyzed. • The composite thermal oil film lubrication model is proposed to predict the overall performance of hybrid journal bearings. • The model contains edge suction heat, hydrostatic pressure loss heat, oil viscous friction heat, and asperity friction heat. • The flow factors and contact coefficients from the actual rough surfaces are used to correct the lubrication and contact model. • The four types of heat play a role in specific conditions and correspondingly cannot be ignored. [ABSTRACT FROM AUTHOR]