Influence of cavitation effects on steady-state performance of water-lubricated bearings

In response to the current research status where the mechanism of cavitation effects in water-lubricated bearings (WLBs) within marine systems remains unclear, this study introduces the JFO (proposed by Jakobsson, Floberg, and Olsson) boundary condition accounting for cavitation effects and couples it with a mixed lubrication model that considers bush deformation and surface asperities. The P–γ model is employed to solve the governing equations, establishing a mixed lubrication model with the capability to describe cavitation. The validity of the proposed model is verified through comparisons with the published literature. Furthermore, a systematic comparison of the steady-state performance of the bearing under JFO and Reynolds boundary conditions is conducted to clarify the influence of cavitation on bearing performance. By examining cavitation regions under different operational conditions, the key mechanisms of cavitation phenomena are elucidated. The results demonstrate that cavitation effects significantly affect the steady-state performance of WLBs. During the mixed lubrication regime, the cavitation effect makes WLBs more prone to solid contact friction. Furthermore, under heavy-load conditions, the proportion of the cavitation area increased from 4.82% at 200 rpm to 9.76% at 1400 rpm as the rotational speed rose. Simultaneously, the cavitation initiation angle in the circumferential direction also expanded with increasing speed (from 193.5° to 218.25°), indicating that the cavitation zone gradually shifted from the lower half to the upper half of the bearing, thereby transitioning from reducing the load capacity to enhancing it. This research provides valuable insight for studying cavitation phenomena in marine propulsion systems operating under complex conditions.