轴流泵出水流道水力损失试验研究

TEST INVESTIGATION ON HYDRAULIC LOSSES IN DISCHARGE PASSAGE OF AXIAL-FLOW PUMP

受导叶出流环量、出水弯管二次流等因素的影响,轴流泵单孔出水流道内为复杂的螺旋流,双孔出水流道左孔流量大于右孔流量,水力损失异常。采用五孔探针准确测定流道断面水流能量,实测分析出水流道水力损失特性,探讨减阻措施。结果表明,出水流道水力损失不符合与流量平方成正比的关系。与等圆出水管相比,渐扩出水流道可以减小水力损失,提高泵装置效率10％～30％;对单孔流道,轴流泵出口环量过大,增大了水力损失, 而微小环量会使水力损失略有减小;对双孔流道,两孔流量不等,存在偏流,水力损失增大。采用微小出流环量或无出流环量后导叶,可减小出水流道水力损失,提高泵装置效率6％-11％。

Under the influence of guide blade discharge circulation, discharge bend pipe secondary flow, the flow in the 1-channel discharge passage of an axial flow pump is complicated spiral flow, the discharge in the left channel is bigger than that in the right one as for 2-channel passage, and the passagehydraulic losses are abnormal. The section current energy of the passage is measured and determined with 5-hole probes accurately. The hydraulic loss characteristics are determined and analyzed. The methods deducing the hydraulic losses are investigated. The results indicate that the passage hydraulic losses are not proportional to the flow discharge. Compared with circle pipe, the hydraulic losses of divergent discharge passage are smaller and the pump assembly efficiency is higher with 10%-30%. As for 1-channel passage, axial-flow pump outlet circulation is too big usually, the passage hydraulic losses are big too, but small circulation can slightly reduce hydraulic losses. As for 2-channel passage, discharges in 2 channels are not equal and the hydraulic losses increase. The outlet guide blade with small discharge circulation or without circulation could reduce discharge passage hydraulic losses and pump assembly efficiency increases with 6%-11%.