Advanced cavitation damage and erosion modeling for journal bearings in high-power density engines: Towards enhanced performance and reliability

Reliability is critical in high-power density engines, where components operate under extreme conditions to achieve optimal performance. These demanding conditions give rise to complex multiphysics and multiscale interfacial phenomena, contributing to early wear stages, poor performance, and catastrophic engine failure due to severe mixed lubrication, cavitation damage, fatigue, and overheating effects. Therefore, enhancing the durability of such engines is paramount. This study investigates cavitation erosion in high-power density engines, with a particular focus on the connecting rod journal bearing. A novel multiscale cavitation erosion (MCE) model is presented, integrated with a mixed-elastohydrodynamic lubrication simulation framework. Realistic boundary conditions for bearing load, oil supply hole position, and pressure are obtained from a multibody dynamic simulation analysis of the entire system. The proposed multiscale cavitation erosion model predicts the cavitation damage energy at each computational mesh node within the macroscopic bearing domain. This energy serves as a threshold to erode the corresponding microscale area surrounding the macroscale node region. The equivalent microscale area is then coupled with the bearing surface topography, and material removal is simulated using a novel cavitation erosion algorithm. The proposed model is applied to evaluate the evolution of cavitation damage in the connecting rod bearing of a motorsport engine. The analysis considers various influencing factors, including engine speed, bearing clearance, lubricant formulation, and oil temperature. The findings reveal key insights into the cavitation erosion mechanisms, highlighting the significant influence of lubricant formulation and engine speed on erosion severity in the studied bearing.