汽轮发电机水路堵塞时定子流体场和温度场的数值仿真

Numerical Simulation on Stator Fluid Field and Temperature Field on Waterway Blockage in Turbogenerators

水冷汽轮发电机冷却水路的堵塞是其常见的故障,水路系统堵塞的检测手段之一是监测其温度的变化。由于水氢氢汽轮发电机采用氢气冷却定子铁芯和转子部分,采用水冷却定子绕组,使得其冷却系统比较复杂,并且流体流动状态直接影响到温度的变化。为了得到较好的温度仿真结果,将流体场与温度场进行耦合,建立了汽轮发电机定子三维流体场与温度场的耦合数学模型。在通过计算汽轮发电机二维电磁场从而获得定子铁芯损耗分布的基础上;利用有限体积法耦合计算了定子的三维流体场和温度场。采用所建立的数学模型,计算了定子线棒空心导线在不同堵塞故障下定子的三维流体场和温度场,总结了定子温度的变化规律:与正常运行相比较,空心导线堵塞时,定子最高温度点的位置由上层线棒的出水口处转移到了被堵塞的线棒;被堵塞的空心导线即使增加1根,也会使得其所在的线棒温度有较大的增加,但是定子铁芯齿部、轭部以及正常线棒的温度增加很少。

The waterway blockage is one of the common faults in water-hydrogen-hydrogen turbogenerators, and one of methods for monitoring waterway system is to monitor the temperature variation of generator. The stator core and rotor are cooled by hydrogen and the stator bars are cooled by water in water-hydrogen- hydrogen turbogenerators, so the heat transfer process is relatively complicated and fluid state directly affects the temperature variation. Thus, we established coupling models for the three-dimensional fluid field and temperature field of turbogenerators. Firstly, the loss distribution of the stator core was obtained by calculating two-dimensional electromagnetic field in generator, then, the control equations of the stator three-dimensional fluid and temperature fields were coupling calculated numerically by the finite volume method. Moreover, the stator temperature distribution was researched when hollow strands were differently blocked. The results reveal that stator maximum temperature spot is changed from wate^outlet of upper bar to blockage bar when stator hollow strands are blocked. Temperature of blockage bar greatly increases as number of blockage hollow strand increases, at the same time, temperature of stator tooth and yoke spots slightly rises, but temperature of healthy bar is basically a constant.