冷却水流速对汽车水冷电机温升影响研究

为获得水冷电机的最佳流速,基于传热学及流体力学理论推导了水冷电机的冷却水流速与电机内部温度的关系。冷却水层流时,电机温度随着流速的增大下降明显;冷却水紊流后,对电机冷却效果进一步增强,但随流速继续增大,电机温度降低程度随冷却水流量增加将出现热饱和;建立了水冷感应电机热网络模型,基于此模型计算了电机额定负载运行稳态温升及不同流速时电机绕组及定子轭部的温度分布;实验测试了样机额定运行及不同冷却水流速时的电机温升。仿真及实验结果与理论分析结果相一致,验证了理论推导的正确性,为水冷电机选择合理的冷却水流速提供参考依据。

Research on the effects of cooling water velocity on temperature rise of the water-cooled motor in electric vehicles

In order to attain the optimal velocity of water-cooled motor’s cooling water,the relationship between velocity of water-cooled motor’s cooling water and motor temperature was derived based on the heat transfer and hydrodynamic theory.Motor temperature decreased more with the increase of velocity,when cooling water was in laminar flow.When in turbulent flow,the cooling effect on the motor was further enhanced,however,with the velocity increasing,motor temperature dropped to heat saturation with increasing cooling water flow.In this paper a model of water-cooled induction motor based on the thermal network was established.The steady-state temperature rise of motor under rated load was obtained and the temperature distribution of the winding and the stator yoke was also calculated when in different velocity of cooling water.Experiments were conducted on an induction motor prototype to measure the temperature of the motor under rated load and in various flow rates of cooling water.The numerical simulation results and experimental results are consistent with the theoretical analysis results,which proves the correctness of theoretical derivation.The study in this paper provides a reference for the water-cooled motor selecting the rational velocity of cooling water.