Abstract
Impact cavitation failure of the bearing is one of the main reliability problems in diesel engines. However, the transient generation mechanisms and key influencing factors of impact cavitation have not yet been sufficiently investigated in existing studies. To address this gap, this study conducts a systematic study of bearing impact cavitation by integrating numerical simulation cavitation process analysis, and structure observation. Firstly, a novel transient CFD (computational fluid dynamics) model is proposed to investigate the impact cavitation process in diesel engines. The model captures the dynamic behavior of lubricating oil flow through the main bearing, oil passage, and connecting rod bearings. By analyzing variations in oil volume fraction, pressure, flow velocity, and flow rate, the transient generation mechanism of impact cavitation is systematically revealed. The key parameters influencing impact cavitation are identified and analyzed. The results show that impact cavitation is mitigated with increasing groove transition angle and oil passage diameter. Specifically, enlarging the oil passage diameter and the groove transition angle increases the oil volume fraction by 16.7% and 46.4%, respectively. Furthermore, the simulation results show good agreement with cavitation patterns observed in practical diesel engine bearings. This study enriches the theoretical understanding of bearing impact cavitation and provides a valuable basis for cavitation analysis and mitigation in engineering applications.
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