大型蒸发冷却水轮发电机的关键问题——定子空心导线内两相流摩擦阻力放大倍数的比较及修正建议

Key Question of Evaporative Cooling for Large Hydrogenerator--Comparison and correctional recommendation of amplificatory multiple oftwo-phase flow frictional resistance inside the stator’s hollow conductor s

蒸发冷却水轮发电机400MW机组的成功运行,标志着蒸发冷却技术已迈入了大容量的等级。为了进一步提高容量,应该准确掌握蒸发冷却技术中的关键问题—两相流的计算,特别是两相摩擦阻力放大倍数的确定。本文就2.5×9.6的矩形空心导线采用仿真计算和模型实验两种手段对目前推荐使用的几种流阻放大倍数计算方法进行了比较,最后对其中的Friedel[1]方法作了修正。结果显示修正后的Friedel方法用于仿真计算,其计算流量和实验测量流量之间的误差小于10%。这说明修正后的放大倍数计算方法是合理的,可以用于大容量机组的循环计算。

Successful operation of 400MW evaporative cooling hydrogenerator indi cated this technique stepping into the large capacity stage. In order to further advance the capacity of hydrogenerators, the key point of evaporative cooling t echnique-calculation of two-phase flow should be more accurately grasped, espe c ially the determination of the multiple of two-phase flow frictional resistance . This paper compared three kind of calculative methods of amplificatory multiple of two-phase flow frictional resistance by selecting rectangular hollow conduc t or with inner size of 2.5×9.6 as investigative object and by using simulative c o mputation and model experiment as investigative methods,and finally make correc tion to Friedel . [1]. method.Correctional result showed that the maximum error betw een computing flux and measured flux by experiment was less than 10 percent. Thi s manifested corrected Friedel method is reasonable and can be used to the calcu lation of evaporative cooling circulating system of large capacity hydrogenerato rs.