Numerical investigation of vibration-induced cavitation for gears considering thermal effect

Abstract

In the lubrication of high-speed gears, cavitation can be induced by the strong vibration and high temperature, resulting in the insufficient lubrication and surface damage. For further understanding the lubrication mechanism between meshing teeth, the research in cavitation problem is essential, benefiting the design and optimization of high-speed gear transmissions. In this study, regarding a pair of spur gears with oil dip lubrication as the research objective, a computational fluid dynamics method coupled with cavitation model, thermal effect and gear dynamics is proposed for the theoretical study of cavitation mechanism, where the novelties are described as: (i) the gear dynamic responses from a finite element model are introduced for simulating the vibration effect; (ii) the cavitation vapor induced by local high temperature is included; (iii) the vapor distribution along tooth width is considered. Compared with the experiments from available researches, this method is validated. The results indicate that cavitation occurs easily at high speed, moreover, the decreased load and increased speed both intensify the fluctuation of cavitation vapor on meshing face, indicating the increased erosion risk. At high speed and heavy load, the local instantaneous temperature becomes very high, aggravating cavitation most significantly, so the thermal effect should not be ignored in this situation.