关于水轮机蜗壳结构不平衡水推力初步研究

A preliminary study of the unbalanced hydraulic thrust in the spiral case structure

为研究内水压力作用下水轮机蜗壳产生的不平衡水推力,采用裸壳和三维实际结构2种计算模型进行有限元计算分析。结果表明:进口附近有伸缩节无止推环的保压蜗壳在运行期座环要承担较大不平衡水推力的受力状态与施工期受力状态有较大差别;垫层蜗壳蜗向局部设垫层时,座环承担的不平衡水推力明显大于垫层全包时的不平衡水推力。应重视不平衡水推力的不利影响。

For study of the unbalanced hydraulic thrust in the spiral case under inner water pressure,two models of bare shell and actual 3D structure were used to make infinite element calculation.The results show that,for the spiral case that holds a certain head inside it and with expansion joint and without anti-thrust ring near the entrance,the unbalanced hydraulic thrust on the stay ring during operation is quite different from that during construction.During operation,the stay ring bears large unbalanced hydraulic thrust.In case the spill case is locally covered with a soft cushion layer,the unbalanced hydraulic thrust on the stay ring is remarkably greater than that when the spiral case is totally covered with a soft cushion layer.Therefore,great attention should be paid to the adverse impact of the unbalanced hydraulic thrust.