方案。
关键词:中型高压异步电动机;通风槽钢;流体场;温度场;优化设计
中图分类号:TM 301.4
文献标志码:A
文章编号:1007-449X(2018)04-0033-09
Abstract:A YKK450-4,500kW medium high voltage asynchronous motor is taken as an example to construct a physical model of inner fan according to the actual scale and the flow condition is analyzed.Then the model of the radial ducts of the motor′s stator and rotor and their adjacent iron cores were constructed.The finite volume method was applied to solve the problem model, and the fluid flow condition,the temperature rise distribution of the stator′s ducts in the calculated region were then obtained. Under the condition that the length of the ventilation channel steel remains unchanged, it rotated with the bottom end near the shaft end being the rotation center,to reconstruct the model to calculate temperature rise. Then the shape of the ventilation channel steel was changed to a natural V-shaped and the model was reconstructed, and it studied the influence of different shapes of the ventilation channel steel on the fluid flow and heat transfer. Furthermore, a pentagonal pyramid was added in the middle of two ventilation channel steels to study the fluid flow condition. Finally, optimization combination was conducted to find the best scheme for the thermal dissipating performance.
Keywords:medium-size high-voltage asynchronous motors; ventilation channel steel; flow field; temperature field; optimal design
0 引 言
YKK系列电机是冷却系统分为内外两个风路的笼型转子电机。YKK系列中高压型异步电机内风路由端部、定转子、另一侧端部和内风扇组成。因为电机的内部风路是不与外界接触的封闭式结构,电机的各个部分在电机运行时热量难以及时散发出去,冷却系统负担加重[1-3]。所以通过了解电机内部的流体流动情况,所以优化电机通风结构,找到使电机温升降低的方法十分重要。
电机内风路流体与传热的计算方法有热路法,等效热网络法和有限体积法。传统的热路方法计算温升,不但准确性较低,而且只能估算绕组和铁心的平均温度。这对于电机特别是大型电机的安全运行过程是一个重要的限制因素[4]。等效热网络法对硬件资源要求低,但网络参数的设置与计算的合理和准确度将直接影响整体的计算精度,很有局限性[5-6]。有限体积法边界适应性好,可以减少数值分析中的假设条件和经验公式的使用,不仅能够预测电机的温度分布,还可以显示电机的最高和最低温度[7-10]。
本文采用有限体积法对电机流体运动形态和流固耦合温升计算进行详细分析,该方法对流固接触面的解决办法是将对流散热系数作为求解公式中的变量来等效,这样就能根据流速来实时的改变流固接触面的对流传热值,从而使数值分析的仿真环境与电机真正运行状况更加符合。天津大学的安蔚瑾对定子的三维温度场进行了数值模拟[11]。哈尔滨理工大学的李伟力研究了通风沟排列方式对永磁同步电机转子流体场和温度场的影响[12]。Y.C.Chen等学者则将实测与仿真结合起来,分析了在不同的速度下,电机内部的散热情况[13]。但国内外学者很少有从改变通风槽钢方面去研究,所以本文在通风槽钢长度不变的情况下,对内风扇进行建模,并旋转通风槽钢且改变其形状,探究不同形状通风槽钢对电机温升的影响。
推荐访问: 流体 风扇 高压 电机 计算