叶片进口安放角对液力透平性能的影响

Effects of blade inlet angle on performance of pump as turbine

针对叶片进口安放角对液力透平性能影响规律认识不足的问题,架设一开式液力透平实验台,对一单级蜗壳式液力透平进行实验研究。采用结构化网格技术对该液力透平进行全流场数值计算与分析,将数值结果与实验结果相结合,验证数值计算的准确性。对不同进口安放角的叶轮进行数值研究。研究结果表明:随着叶片进口安放角的增加,液力透平小流量工况的效率有所下降,大流量工况的效率有所增加;透平的扬程和轴功率随着进口安放角的增加而增加;叶轮内部的功率损失是透平内部主要的功率损失;当叶片安放角增加时,小流量工况的功率损失有所增加,大流量工况下的功率损失有所减小;大流量工况下随着叶轮进口安放角的增加,进口液流冲角逐渐减小,因此,透平在大流量工况下功率损失减小,效率提高。

With respect to the insufficient understanding of the effects of blade inlet angle on the pump as turbine （PAT）, an open PAT test rig was built to investigate a single stage volute type PAT. Numerical simulation and analysis of all domains were done by adopting structural mesh technique. Through numerical and experimental comparison, the accuracy of numerical simulation was proved. The results show that with the increase of blade inlet angle, its efficiency decreases at small flow rate and increases at large flow. The required pressure head and generated shaft power increase with the increase of blade inlet angle. The power loss within impeller takes up the majority of the total power loss. The power loss within impeller decreases at small flow and increases at large capacity as the blade inlet angle increases. Fluid attack angle decreases when blade inlet angle increases at large flow that causes the decrease of power loss within impeller and increase of efficiency.