大型水轮发电机转子旋转状态下磁极间流体流动与温度场分析

Fluid Flow and Temperature Field Analysis Between Two Poles of a Large Air-cooled Hydro-generator Rotor in Rotation

以1台250 MW大型水轮发电机为例,建立了流体与固体耦合传热三维模型,采用共轭传热法对转子半个轴向段的流体场与温度场进行了计算。分析了磁极间隙内流体流动形态对励磁绕组冷却效果的影响和不同入口流量下磁极间涡流变化规律。为减小涡流对转子散热的抑制作用,在转子磁极间增加一轴径向挡风结构,并通过数值模拟分析了挡风结构对涡流的减弱作用以及对励磁绕组冷却效果的影响。

Taken a 250 MW air-cooled large hydro- generator as an example, the three-dimensional flow-heat transfer coupling model of the fluid and temperature was established, and the fluid and temperature fields of half axial rotors were calculated using the conjugated heat transfer law. Then the influence of fluid flow shape to cooling performance of excitation windings, and the change regularity of the vortex under different inlet flow situations between two poles were analyzed. Additionally, a windshield structure was added between two poles in order to reduce the inhibition effect of vortices to rotor cooling. After calculation, it can be proved that the windshield structure could reduce the inhibition effect. So the high temperature rise of excitation windings could be controlled effectively, and the operation reliability of the large hydro-generator rotor is improved.