吸入室对双吸中开泵汽蚀特性的影响

Influence of Suction Chamber on Cavitation Performance of Double Suction Split Pump

针对双吸中开泵吸入室结构的自由性和复杂性加大了设计难度、改变了叶轮的进口流动环量及均匀度并影响泵的汽蚀性能,采用理论方法研究了叶轮进口环量对汽蚀性能的影响,并对一单级双吸中开式离心泵的吸入室进行了优化改型,用数值模拟和试验方法验证了改进型半螺旋吸入室对叶轮汽蚀特性的改善效果。结果表明,进口稍微带正环量能改善叶轮的汽蚀性能,但正环量加大到一定程度后汽蚀又会逐渐恶化;吸入室对叶轮汽蚀的影响因素包括叶轮进口环量和进口流场的均匀度,改进型的半螺旋吸入室提供了叶轮进口的正环量,并提高了叶轮进口流场的均匀度、大幅降低了泵的必需汽蚀余量。

The unconstraint and complexity of the chamber of double suction split centrifugal pump increased the dif ficulty of design, as well as changed the circulation and uniformity of the impeller inlet flow field with affected cavitation performance of the pump. This paper conducted a study on the influence on cavitation performance by circulation up stream the impeller with theoretical approach, and optimized a chamber of a single stage double suction split centrifugal pump, followed by the numerical and experimental research on the improvement of the cavitation performance of the a meliorated semi spiral suction chamber to the one of the original OS type double suction split pump. The study found that the slightly positive circulation imported into impeller can meliorate the cavitation performance, which would aggravate on the contrary when the circulation increases to a certain extent. The factors which influence the cavitation performance of impeller include the circulation upstream the impeller and uniformity of the inlet flow. The improved semi-spiral suction chamber provides positive circulation upstream the impeller, raises the uniformity of the impeller inlet flow field, and re- duces the NPSHr greatly.