某轴向无刷励磁机多方案通风三维热流场分析

Analysis of Three Dimensional Thermal and Flow Fields for the Brushless Exciter with Full Axial Ventilation under Multi-scheme

以7.8 MW无刷励磁机现运行方案为基础,对通风冷却系统进行优化,提出了以改变现方案下通风结构、空气入出口位置的多种方案。建立其整机流固耦合物理模型,基于计算流体动力原理,采用有限体积法,给定边界条件,对多方案下励磁机热流场进行数值计算并进行对比分析。结果表明:改变现方案通风结构,励磁机内空气压力、速度、温度分布规律与现运行方案基本相同,但定转子部件处平均温度不同,最高温度仍位于远离整流盘侧的转子线棒端部,均低于原方案的最高温度;现方案下互换空气入出口位置,对励磁机的热流场有较大影响,最高温度在靠近整流盘侧的定子线棒端部。研究结果为结构类似的励磁机的优化设计提供理论指导。

According to the existing scheme of 7.8 MW brushless exciter,the ventilation and cooling system is optimized and a variety of schemes are proposed to change the ventilation structure,rotation direction and inlet position of the present scheme in this paper.The fluid-solid coupling model of the whole machine is established.Numerical calculation of heat flow field of exciter under multi-scheme is made and compared by adopting the finite volume method and giving boundary conditions based on the principle of computational fluid dynamics.Changing the ventilation structure of the present scheme,the results show that the distribution law of air pressure,the velocity and temperature in exciter are basically the same as that of current operation,the average temperature of stator and rotor parts is different,and the maximum temperature remains at the end of the rotor bar far from the rectifier panel and is lower than the maximum temperature of the original scheme.Exchanging inlet and outlet position under present scheme,it has a great influence on the heat flux field of the exciter,and the maximum temperature is at the end of the stator bar near the rectifier plate.The research results provide theoretical guidance for the optimal design of the exciter with similar structure.