Analysis of Thermo-Flow Coupling in a High-Speed Cylindrical Roller Bearing under Variable Speed Conditions

Abstract To address the issue of high-temperature failure in cylindrical roller bearings under rapid acceleration and deceleration conditions, a computational model for thermal-flow coupling of oil-air two-phase flow was established. The model was based on the Volume of Fluid (VOF) and Multiple Reference Frame (MRF) methods. The motion of bearing components was implemented via Fluent User-Defined Function (UDF). The influence of acceleration and deceleration conditions on the inter-ring lubrication status and temperature rise characteristics was analyzed, and the underlying mechanism was investigated. The results demonstrate that during the startup phase, the oil-air two-phase distribution undergoes significant fluctuations, and distinct “peaks” and “troughs” are observed in the bearing temperature profile. Under short-term acceleration/deceleration, higher acceleration rates and shorter durations reduce the oil distribution within the bearing cavity, leading to a greater temperature rise. Furthermore, different oil supply methods exhibit distinct effects on oil distribution and temperature rise. For engineering applications, advancing the oil supply timing is proposed to reduce the peak temperature during bearing acceleration.