Numerical evaluation of the heat transfer performance of water-cooled system for electric vehicle drive motor based on the field synergy principle

Thermal management of drive motors is a challenging design for transport electrification industries such as electric vehicles. Due to the high heat transfer performance, water-cooled system have become one of the technologies to meet the needs of these industries. Meeting the synergy between the heat transfer performance of the water-cooled system and the heat generated by the motor is key to taking advantage of the performance of drive motors. This study numerically evaluates and experimentally investigates the heat transfer performance of the electric vehicles drive motor water-cooled system based on field synergy principle, discussing the synergy between the temperature gradient field and velocity field of the water-cooled system under different cooling conditions, and the calculated results are consistent with the test results. By observing the interaction between the fluid vortexes and the main flow, the distribution pattern of the synergy angle in the cooling channels was determined. The results show that when the heat transfer capacity of the water-cooled system reaches its peak, the increase in Reynolds number instead leads to the increase in the average synergy angle of the whole field, which ultimately causes a deterioration of synergy between the velocity and temperature gradient fields.