冷却塔水轮机椭圆蜗壳的设计与数值模拟

Design and Numerical Simulation of Elliptic Spiral Case of Turbine in Cooling Tower

针对冷却塔中水轮机采用圆断面蜗壳导致的占用空间大的问题,提出采用椭圆断面蜗壳代替圆断面蜗壳的改造思路。以某冷却塔专用水轮机为例,在圆蜗壳的基础上,遵循蜗壳内水流周向平均速度为常数和相应截面面积相等的规律,设计了一种长短轴比为黄金比例0.618的椭圆型蜗壳,利用CFD数值模拟技术,在额定工况下对所设计的椭圆蜗壳和圆蜗壳的流场进行分析比较。结果表明,采用的椭圆蜗壳具有良好的水力性能,且椭圆蜗壳的横向控制尺寸得到了明显的减少,为今后水轮机蜗壳设计提供了借鉴。

In view of the large occupied space caused by the circular spiral case of the turbine in the cooling tower,the reform idea was put forward with the ellipse spiral case instead of circular spiral case.Talking a certain turbine in cooling tower as research objects,on the basis of the circular spiral case,following the rule of tangential velocity of water flow in the spiral case as a constant and the equal corresponding section area,a elliptical spiral case that the ratio of long and short axis is golden ratio 0.618 was designed.Under the rated operating conditions,the flow field of elliptical spiral case and circle spiral case was analyzed by using CFD numerical simulation technology.Results show that the elliptical spiral case can get well hydraulic properties and its lateral control size has been significantly reduced.Thus,it provides a reference for hydraulic turbine spiral case design.