椭圆型蜗壳设计与CFD分析

椭圆型蜗壳最大优点是蜗壳断面向纵向延伸，与传统的带蝶形边假椭圆不同，它是箱式结构的断面可以用椭圆函数表达的真椭圆，在流速系数相同的条件下，能够减小蜗壳控制尺寸，或者在控制尺寸相同情况下，适当增加转轮直径。通过优化设计，椭圆型蜗壳可获得优异的水力性能。但是，椭圆的长宽比不可无限增大，本文通过CFD分析，给出椭圆型蜗壳长宽比的限制值。

Design and CFD Analysis of Spiral Case with Ellipse Shape Section

The advantage of spiral case with ellipse shape sections, which differs from the traditional spiral case of transition arc, is that the sections are longer in the vertical direction, and the profile of the section shape can be expressed by an arithmetic formula. The ellipse shape section spiral case can reduce the control size with the same velocity coefficient or can enlarge the diameter of runner with the same control size. The ellipse section spiral case can give excellent hydraulic performance by optimizing design. However,the aspect ratio should be limited to some range. This paper gives the limited value of aspect ratio by CFD analysis.