Two-Way Coupled CFD Approach for Predicting Gear Temperature of Oil Jet Lubricated Transmissions

This article focuses on the development of a two-way coupled methodology to predict gear temperature of oil jet lubricated transmissions using commercial software for computational fluid dynamics simulation. The proposed methodology applies an overset mesh technique to model the gear interlocking motion, multiphase of air-oil mixture, and heat transfer. Two gear pairs were used to develop and validate the methodology, an overdrive helical gear pair of a commercial vehicle transmission and a standard spur gear pair. Different oil jet lubrication methods were investigated using the proposed methodology, such as oil jet directed at the into-mesh position and at the out-of-mesh position. This investigation showed that out of mesh lubrication direction shows better cooling performance which is in well agreement with previous studies of literature. Gear temperature was measured on the spur gears under several operating conditions by a set of thermocouples placed near the tooth contacting surface and 180 degree apart. A good correlation of predictions and measurement results were obtained for all cases within 12 °C of maximum deviation. The proposed two-way coupled CFD approach can be used to develop oil jet lubrication systems for effective gear cooling and reduced power loss.