空冷汽轮发电机冷却气流风量对定子内流体的影响

Influence of Air Current Flow Change on Fluid Flow and Heat Transfer of Air-cooled Turbo-generator With Multipath Ventilation

根据大型空冷汽轮发电机多风路通风系统内流体流动与传热的特点,建立定子多风路通风系统三维流动与传热耦合计算的物理模型与数学模型,并给出求解域相应的边界条件及假设条件,采用有限体积法对三维流体场和温度场控制方程进行耦合计算;在保证总风量不变的情况下,分析改变定子、气隙风量对定子各个径向通风沟内的流体速度、温度及电机各部分温度空间分布特性的影响。结果表明,适当增加气隙风量,会降低电机定子最高温度,还会降低电机定子最高温度与最低温度的温差。最后,以200MW两级大容量空冷汽轮发电机为例进行计算,将计算结果与实测结果进行比较分析,证明该方法的准确性。

The mathematical and physical models for the 3-D fluid and temperature coupling analysis of the stator multipath ventilation system for large air-cooled turbo-generators are established according to the characteristics of fluid-flow and heat-transfer. Meanwhile, the corresponding boundary conditions under some assumptions were given. The control equations of the stator 3-D fluid and temperature fields are coupling calculated numerically by using the finite volume method （FVM）. Then keeping the total input air invariant, the influence of changing the air volume in the stator and air gap on the fluid temperature and velocity in every stator duct, the space temperature distribution of generator were studied. The results show that, the highest temperature of stator and the difference between the highest and lowest temperature of stator are decreased by air flow increased properly. Finally, a 200 MW air-cooling turbo-generator is taken as an test example, theoretical approach together with experimental results confirms the validity of the proposed method.