Investigate on the Fluid Dynamics and Heat Transfer Behavior in an Automobile Gearbox Based on the LBM-LES Model

With the rapid development of the new energy vehicle market, the demand for efficient, low-noise, low-energy consumption, high-strength, and durable gear transmission systems is continuously increasing. Therefore, it has become imperative to conduct in-depth research into the fluid heat transfer and lubrication dynamics within gearboxes. In gear systems, the interaction between fluids and solids leads to complex nonlinear heat transfer characteristics between gears and lubricants, making the development and resolution of gearbox thermodynamic models highly challenging. This paper proposes a gear lubrication heat transfer dynamics model based on LBM-LES coupling to study the dynamic laws and heat transfer characteristics of the gear lubrication process. The research results indicate that the interaction between gears and the intense shear effects caused by high speeds generate vortices, which are particularly pronounced on larger gears. The fluid mixing effect in these high vortex regions is better, achieving a more uniform heat dissipation effect. Furthermore, the flow characteristics of the lubricant are closely related to speed and temperature. Under high-temperature conditions (such as 100 °C), the diffusion range of the lubricant increases, forming a wider oil film, but its viscosity significantly decreases, leading to greater stirring losses. By optimizing the selection of lubricants and stirring parameters, the efficiency and reliability of the gear transmission system can be further improved, extending its service life. This study provides a comprehensive analytical framework for the thermodynamic characteristics of multi-stage transmission systems, clarifying the heat transfer mechanisms within the gearbox and offering new insights and theoretical foundations for future research and engineering applications in this field.