基于CFD的微水头双向水轮机叶片比选及整机性能分析

Blade Comparison and Selection and Performance Analysis of Micro-head Bidirectional Turbine Based on CFD

针对微水头双向灯泡贯流式水轮机叶片翼型和形状对其性能的影响,在相同设计水头下,对3种叶片的微水头双向贯流式水轮机进行了CFD数值模拟,对比分析了正反向工况下3种叶片的水轮机的外特性(流量、效率、出力)、叶片表面静压分布和相对流速矢量分布,最终确定了叶片C为较优叶片,进而分析了较优水轮机模型下的各部分水头损失以及内部流场规律。结果表明,正向工况下由于灯泡体后置,使得出水流道内出现回流、漩涡等不良流态,增加了撞击损失,故正向工况的效率低于反向工况。

According to the influence of blade shapes and blade airfoil on the performance of the micro-head bidirectional tubular turbine,numerical calculations based on CFD were carried out to simulate its three-dimensional turbulent flow with three blades in different shapes by setting the same design head.Compared the discharge,output,efficiency of three approaches in obverse and reverse working condition,the better scheme on the shape of blades was finally determined by analyzing static pressure distribution and relative velocity distribution of the surfaces of three different blades contrastively.And then the water head loss of the optimal model and the rule of its inner flow field are analyzed.The results show that the phenomena of vortex and circumfluence appeared in outflow channel due to the post-posed bulb in positive condition,which increased the hydraulic loss.Therefore,it leads to much lower efficiency in positive direction compared with negative direction.