Optimization of splash lubrication in the gearbox considering heat transfer performance

Abstract

Despite recognizing the importance of cooling within gear systems, there is a lack of clear design guidelines to minimize churning losses while enhancing heat dissipation performance. This study proposes a reliable approach to modeling using a steady-state approximation methodology based on heat-flow coupling for multiphysics around shrouded gears. Computational analyses reveal a distinctive multiphase flow induced by pressure gradients. The efficacy of the proposed methodology is empirically verified through its ability to characterize lubricant distribution and churning losses in splash lubrication systems. Furthermore, an innovative shroud optimization framework is introduced to regulate friction and collision between fluid particles and gear surfaces, enhancing splash lubrication performance. A genetic algorithm is employed within this framework to obtain shroud configurations for gears with a higher wall heat transfer coefficient (WHTC) and lower resistance torque. Implementing the optimal shroud design achieves a trade-off in terms of a notable 13.7% reduction in resistance torque alongside 11.6% and 4% increments in WHTC for the tooth root face and tooth face, respectively. This signifies enhanced reliability in multiphysics governing gearbox functionality, thereby providing valuable guidance for the design of shrouded gear systems.