低比转数离心泵驼峰现象的CFD分析

为揭示低比转数离心泵性能曲线产生驼峰现象的内流机理,采用RANS方法算法对一低比转数离心泵2个方案(有驼峰和无驼峰)下的内部进行了全流场CFD计算,重点分析了驼峰现象产生时2个方案内部流动结构的差异。结果表明:性能曲线出现驼峰时,2个方案的靠近蜗壳隔舌的叶轮流道内的流动结构差异最为明显;该流道内叶片压力面的低速区会明显增大并伴有漩涡流动;该流道进口也会出现明显的漩涡流动引起进口冲击损失增加;同时该流道出口的"射流-尾迹"现象也会突变,引起出口(混合)水力损失增加。因此这些损失的增大是引起驼峰现象的重要原因。

CFD Research on Hump Phenomenon of Low Specific Speed Centrifugal Pump

In order to study the hump of pump performance curve in low specific speed centrifugal pumps,using RANS method algorithm to CFD calculations of internal full flow of low specific speed centrifugal pump in two schemes( has a hump and without the hump) to calculate and analysis. Differences of the internal flow structure are emphatically analyzed in two schemes when hump phenomenon occurs. The results show that the performance curve appeared hump,the flow structure differences of the impeller flow passage near the volute tongue in two programs are the most obvious. Low speed area in the pressure side of the impeller blade in the passage can significantly increase accompanied by vortex flow. The flow of imports also appear obvious vortex flow,losses increased by the impact of the vortex flow. Meanwhile,the " jet-wake" phenomenon of the channel outlet also mutate,causing exports hydraulic losses increase. Therefore,the increase of these losses is the significant cause of hump phenomenon.