糯扎渡水电站水轮机蜗壳水压试验情况及分析

糯扎渡水电站首批安装的3台水轮机蜗壳采用椭圆型断面，水压试验时蜗壳变形严重。通过对蜗壳水压试验产生严重变形的原因分析、实体有限元分析、模拟试验和处理方案比选，采取了将蜗壳部分椭圆形断面改变为圆形断面形式，进口段增加2个混凝土支墩的处理方案。计算数据与水压试验结果对比表明，改造后的蜗壳符合设计标准，满足安全运行要求。

Analysis on hydrostatic test of hydraulic - turbine spiral case of Nuozhadu Hydropower Station

The elliptic cross-section was designed for the first batch of 3 hydro-turbine spiral cases installed in Nuozhadu Hydropower Station,however,serious deformation of the spiral cases appeared in the hydrostatic test.Through the analysis of the deformation causes,FEM analysis,simulation experiment of the treatment and the comparison and selection of deformation treatment schemes,it is proposed that some of the elliptic cross-sections are changed into round cross-sections,and 2 concrete rest piers are added at the entrance section.The comparison of simulation and experimental results shows that the spiral cases meet the design standard and demand of safe operation after modification.