低扬程立式轴流泵出水流道基本流态及水力性能的比较

采用数值计算和模型试验的方法对低扬程立式轴流泵虹吸式和直管式2种不同形式的出水流道进行了比较,揭示了这2种出水流道的基本流态,测试了这2种形式出水流道的水力损失。结果表明:在低扬程的条件下,虹吸式出水流道内的水流转向更为有序、扩散更为平缓、水力损失更小,对于年运行时数较多的大型低扬程泵站,在上游水位变幅允许的条件下,应优先选用水力性能较好的虹吸式出水流道。

Comparison of Hydraulic Performance of Outlet Conduit for A Vertical Axial-Flow Pump with Low Head

Comparison between 2 types of outlet conduit was executed by both numerical calculation and model test. The conduits, including siphon outlet and straight-tube outlet, are usually applied for a vertical axial-flow pump with low head. The basic flow patterns in the conduits were illustrated, and their hydraulic losses were also measured. The results make it clear that there are more obvious differences in both flow patterns and hydraulic losses between the 2 types of the conduit. The flow in siphon outlet turns and diffuses in a much more orderly way, and its hydraulic lost is lower. Consequently, siphon outlet, with the better hydraulic performance, should be preferentially chosen for a large pump station with low head and long runtime, if the variation of upstream water level is permitted.