整流罩结构对电机机座表面对流传热特性的影响

为了尽可能地降低全封闭风扇冷却（TEFC）电机各部件的温升，避免过高温升对绝缘结构的破坏，采用数值计算方法研究了整流罩结构对TEFC电机机座表面对流传热特性的影响。首先，对一台样机进行温升试验，绕组温升的仿真值与试验值的误差为6.2%，验证了数值计算方法的可行性。其次，在数值计算时将样机三维模型做必要的简化，着重研究了整流罩外径、整流罩端面与翅片端面的间距以及电机转速对机座表面横向平均努塞尔数的影响。最后，结果表明机座表面翅片结构一定时，存在一个最佳的整流罩外径值使机座表面的对流传热效果最佳；整流罩端面与翅片端面接触时，机座表面的横向平均努塞尔数最大，同时机座表面的对流传热能力随着风扇转速的增大而增大。

Influence of Cowling Structure on Convective Heat Transfer Characteristic of Motor Housing Surface

In order to reduce the temperature rise of the components of the totally enclosed fan cooling (TEFC) motor as much as possible and avoid the damage of the insulation structure caused by the excessive temperature rise, the influence of the cowling structure on the convective heat transfer characteristic of the TEFC motor housing surface is studied by numerical calculation method. Firstly, the temperature rise experiment is carried out on a prototype. The error between the simulated value and the experimental value of the winding temperature rise is 6.2% and the feasibility of the numerical calculation method is verified. Secondly, the necessary simplification of the three dimensional model of the prototype is made in the numerical calculation. The influences of the outer diameter of the cowling, the distance between the end face of the cowling and the end face of the fin, and the motor speed on the lateral average Nusselt number of the housing surface are studied emphatically. Finally, the results show that when the fin structure on the housing surface is fixed, there is an optimal value for the outer diameter of the cowling to make the convective heat transfer effect on the housing surface optimal. When the end face of the cowling is in contact with the end face of the fin, the lateral average Nusselt number of the housing surface is the largest. In addition, the convective heat transfer capacity of the housing surface increases with the increase of the fan speed.