大型空冷汽轮发电机定子通风结构优化方案的计算与分析

Calculation and Analysis on Stator Ventilation Structure of Different Optimum Proposal in Air-cooled Turbogenerator

随着空冷汽轮发电机容量增加,其组件的可靠性依赖于冷却系统散热能力。合理的优化发电机定子通风结构,可以提高传热介质的利用率,降低电机温升。在200MW空冷汽轮发电机定子实验研究数据和大量相关工作基础上,提出了2种方案对电机定子结构进行优化:方案1,保持电机总尺寸、损耗和通风沟数量的不变,改变铁心厚度;方案2,保持电机总尺寸和损耗不变,增加通风沟的数量同时减小通风沟尺寸。根据计算流体力学原理,应用有限体积法求解定子各径向风沟内空气的紊流流动等三维离散方程组,研究了通风沟尺寸结构等几何量变化对整个电机温度场和流体介质的利用率的影响。研究结果表明,优化后的2种结构能使流体带走更多的电机内产生的热量,使计算出电机的稳态温升比实际结构计算出的温升最大下降9.13℃。

With the increase of turbogenerator capacity,the heat transferability of cooling system is becoming more and more vital to the component reliability. By reasonablely optimizing the stator structure in a turbogenerator,utilization rate of coolant could be improved,and the maximum temperature of turbogenerator could be reduced. Based on the experimental data and plenty of related operations of a 200 MW air-cooled turbogenerator,two optimization designs about stator structure were proposed. One was to change the iron core thickness with the stableness of overall size,total losses of stator core and the number of stator ventilations,the other is to increase the number of ventilations and reduce their length with the stableness of the overall size and total losses of stator core. With CFD principle and 3-D finite volume method,the modeling equations of air turbulent flow in cooling ducts are solved,and the effect of the ventilations＇ structure changing on coolant utilization ratio and distribution of stator temperature were studied. The study shows that,by adopting the two optimal structures,coolant can take away more heat from generator and the maximum temperature of generator can be reduced up to 9.13 ℃ more than original structure.