定速法设计的蜗壳性能数值分析

Numerical Analysis of the Performance of Volute Designed with Constant Velocity Method

以等速度矩理论设计的混流式水轮机蜗壳,因尾段半径小致使蜗壳内壁流速大,在多泥沙河流中运行时造成蜗壳尾段的磨损剧烈。为此,给定蜗壳断面平均流速规律,以此为据进行蜗壳水力设计,从而使尾段流速降低以达到减缓泥沙磨损的目的。对以等速度矩理论和给定流速分布规律方法设计的4个蜗壳进行了水轮机全流道数值模拟,通过对绝对流速、径向速度、进口环量和液流角的分析,选定了一种较好的蜗壳抗泥沙磨损改造方案。

The mixed-flow water turbine volute designed by the theory of constant velocity moment encountered a seriously abrasive trailing end during its running in sediment-laden river,which was caused by the high flow rate in the inner wall of volute that was resulted from the small radius of trailing end.Thus,the hydraulic power of volute was designed on the basis of a given average flow rate law on the volute section,so as to reduce the flow velocity of trailing end for the purpose of slowing down abrasion of sediment.The numerical analysis of whole flow passage of water turbine was conducted on the four volutes designed by the theory of constant velocity moment theory and with the given flow rate distribution law method,and a more effective anti-sediment abrasion modification scheme for volute was selected through the analysis of absolute flow rate,radial velocity,inlet circulation and fluid flow angle.