3D Transient CHT Simulation of Frictional Heating in Jet-Lubricated Automotive Gears

Gears play a critical role in automotive transmission systems. During operation, frictional heat is generated in the intermeshing region due to loading. Effective lubrication and cooling are essential to minimize heat generation and ensure smooth operation. Lubrication failure can lead to a significant local temperature rise, potentially causing gear scuffing—a phenomenon where intermeshed gear teeth weld together and tear apart during rotation—resulting in severe damage and compromised transmission performance. To prevent this, gears are typically lubricated using splash or jet lubrication techniques. This study presents a Conjugate Heat Transfer (CHT) simulation of a jet-lubricated gear pair in an automotive transmission system to predict the local temperature rise due to frictional heating in the intermeshing region of the gears. The paper focuses on implementation of the frictional heat generation on the gear teeth and resultant transient temperature rise in the gear contact region. A commercial CFD tool, Simerics MP+ is used for the 3D CHT simulation. The methodology employs a multiphase Volume of Fluid (VOF) approach to capture the interaction between oil and air while utilizing a mixed timescale coupled approach for heat transfer analysis. The resulting local temperature distribution on the gear teeth is analyzed and validated with the test data.