水泵叶轮直径对低扬程泵装置水力性能的影响

采用数值计算的方法,分别计算了具有不同水泵叶轮直径的立式轴流泵装置和灯泡贯流泵装置的流道水力损失,比较了水泵叶轮直径对流道水力损失的影响;根据叶片泵的相似律,分析了在一定设计流量条件下水泵叶轮直径与nD值的关系以及对水泵选型设计的影响。结果表明：选取较大的水泵叶轮直径将显著提高流道效率和泵装置效率;＂增径降速＂与降低nD值是一致的;在泵装置扬程较低的情况下,选取较小的nD值便于选用到水力性能较好的轴流泵水力模型。

Influence of Pump Impeller Diameter on the Hydraulic Characteristics of Low Head Pump System

The hydraulic loss of conduit in both vertical pump system and bulb tubular pump system were calculated using the numerical simulation, and the influence of pump impeller diameter on hydraulic loss of conduit was analyzed. Based on the similitude rules of impeller pump, the relationship between pump impeller diameter and nD value and the influence of pump selection and design were analyzed. It is could be concluded that the larger pump impeller diameter may obviously increase the efficiency of both conduit and pump system; increasing pump diameter and decreasing its rotational speed is consistent with reducing nD value. It is suitable to pump system with low head to choose lower nD value, so as a hydraulic model of axial flow pump with the better hydraulic characteristics could be obtained.