中文摘要：

水轮机金属蜗壳设计中不同断面结构型式的选择，会在一定程度上影响结构的受力特性和厂房布置尺寸。为分析金属蜗壳不同断面型式结构受力特性，对非圆形的三心圆蜗壳断面与圆形蜗壳断面结构在充水保压阶段进行了有限元数值计算。研究结果表明：相比于圆形断面蜗壳结构，三心圆蜗壳在充水保压时蜗壳直管段会发生较大的水平偏转位移，座环整体在水平向的变位也相对更大，对钢蜗壳整体的变形控制要求更高；而钢蜗壳断面内环向应力数值略有减小，但整体应力水平变化不大。因此，从水压试验和保压阶段蜗壳与座环结构的变形控制角度来看，在高水头充水保压蜗壳结构中采用非圆形断面蜗壳结构是不合适的。建议今后在金属蜗壳结构设计和埋设方式选择时，应该充分重视不同蜗壳断面结构型式对结构受力特性的影响，确保水电工程的顺利建设和安全运行。

英文摘要：

The layout size of hydropower house and the mechanical characteristics of the structure will be partly influenced when different cross section styles of steel spiral case were chosen. In order to analyze mechanical characteristics of steel spiral case with different cross section styles, spiral cases with a three-centred cross section and a round cross section were calculated by FEM at the stage of keeping constant internal pressure. Compared to the spiral case with round-section, larger horizontal displacement appeared at the straight pipe of the spiral case at the stage of keeping constant internal pressure when the three-centred cross section was selected and also the horizontal displacement of the stay ring would be larger. The deformation controlling of the whole steel spiral case will be more difficult. Yet, the circumferential stress in the section of spiral case decreased slightly and the change of the stress of the whole structure is just a little. In the view of the deformation controlling of the spiral case and the stay ring at the stage of hydrostatic test and preloading, the steel spiral case with noncircular cross section is not suitable for the spiral case structure keeping constant internal pressure with high water head. When designing the steel spiral case and choosing the embedded manners, the mechanical characteristics of the spiral case with different cross section styles should be focused on to ensure that the hydroelectric project could be constructed smoothly and operated safely.