全蜗壳的非圆形断面水力设计及其CFD分析验证

Hydraulic design of spiral casing with non-circular section and its verification with CFD analysis

针对水轮机全蜗壳常规水力设计方法中存在的不足,对蜗壳中水流遵循速度矩为常数规律运动的非圆形断面水力设计进行分析,利用数值计算方法,使蜗壳尾部圆断面内的水流遵循速度矩为常数的运动规律,而无需转换成椭圆断面,从而完善蜗壳非圆形断面的水力设计方法.经实例设计与CFD流场模拟分析验证表明,采用文中所提出的非圆断面设计方法设计出的蜗壳,水流运动基本符合设计假定,其流场分布与理论分析相符合,设计出的蜗壳流道平顺光滑,流态分布良好.

Aimed at the defects present in conventional hydraulic design method of full spiral casing, the hydraulic design of spiral casing with non-circular section, in which the flow observes constant velocitymoment law was analyzed and approached. The numeric approach was used to make the flow in the end section of spiral case with circular section observe constant velocity-moment law without the need to transform it into an oval-shaped section, so that the hydraulic design method of spiral case with non-circular section was improved. It was shown by an actual design practice and flow field simulation with CFD analysis that, by using the presented design method of spiral case with non-circular section, the flow pattern in the spiral case was basically consistent with the design assumption, the flow field was consistent with that obtained by means of theoretical analysis, the flow passage in spiral case was smooth, and the distribution of flow form was fine.