CFD-vibration coupled model for predicting cavitation in gear transmissions

Abstract

Cavitation occurs in gears during transmissions at high speeds, making it a major obstacle in the development of high speed and high accuracy gear trains. However, there has been limited research to study the cavitation mechanism. This paper reports on a computational fluid dynamics (CFD) model coupled with gear vibration developed to investigate the vibration-cavitation mechanism. First, a finite element model is employed to obtain the characteristics of gear vibration, which are imposed on the CFD model boundary during the dynamic flow analysis. For the cavitation simulation, the Zwart–Gerber–Belamri model is employed in conjunction with the k-ε turbulence governing equations. Subsequently, the CFD-vibration coupled model is validated by comparing with experiments. Finally, the distributions of vapour and pressure in the meshing region are presented, and the effects of rotational speed, torque, gear module, and lubricant viscosity are discussed. Moreover, the evolutions of vapour and pressure on the tooth meshing face are analysed. The results show that cavitation is aggravated at high speeds, low loads, high gear modules, and low viscosities, and extreme pressure fluctuations occur at the pitch point. Therefore, this study provides a valuable tool for optimizing high-speed gear transmission systems.