地铁用电机传热特性数值模拟与实验研究
Numerical Simulation and Experimental Investigation on the Heat Transfer Characteristics of a Metro Motor

为研究电机的超温问题,以负载状态的地铁用电动机为例,考虑电机结构的不对称性,建立三维全域物理模型。采用ANSYS软件,旋转部件应用多重旋转坐标系,进行流动与传热耦合仿真计算,探究了额定状态下电机内流场和温度场分布特点,以及转速和环境温度对其流动、传热特性的影响。此外,采用预埋热敏电阻的方法对在额定工况运行的电机定子线圈进行测温,验证了数值模型的可靠性。数值分析结果表明:从纵截面来看,轴向中心平面偏非传动端侧约25 mm处温度最高;从横截面来看,机箱底部与接线组支撑组件的夹角范围内温度最高,故全域模型比对称模型更合理。此外,随着电机转速增大,定子线圈最高温度近似线性升高,转速平均每升高1 000 r/min,定子线圈最高温度升高6.2％,最高温升升高7.5％;随着工作环境温度升高,定子线圈最高温度近似线性升高,定子线圈最大温升也有小幅升高,环境温度平均每升高10℃,最高温度提高10.1％,最高温升提高2.3％。
To investigate the over？？temperature problem of motors, this study took a loaded metro motor as the research object, and established a three？？dimensional physical model taking the asymmetry of the motor structure into account. The flow and heat transfer characteristics were computed through coupled simulation using ANSYS. When the flow and temperature fields were under rated condition, the internal flow and temperature fields distribution characteristics of the motor and the influences of rotating speed of motor and ambient temperature on the flow and heat transfer characteristics were investigated. In addition, the experiments used embedded thermal resistors to measure the temperature of the stator coils in the rated condition, which verified the reliability of the numerical model. The numerical results suggest that in the longitudinal section through the axis, the peak temperature emerges at the position about 25 mm from the middle plane at the non？？driving end; and in the cross section, the peak temperature emerges in the area between the bottom and the component supporting the input wires. So a complete model is more rational than the symmetrical model. In addition, it is shown that with the increase of rotating speed, the highest temperature of the stator coils rises linearly, and that the peak temperature increases by 6.2％ and the maximum temperature rise increases by 7.5％ for each speed rise of 1 000 r/min. The highest temperature of the stator coils increases linearly with the ambient temperature, and the highest temperature rise of the stator coils also goes up slightly. The peak temperature increases by 10.1％ and the maximum temperature rise increases by 2.3％ when the ambient temperature is raised by 10℃