混流泵叶轮内部流动的PIV实验

Experimental Study on the Flow in Mixed Pump Impeller by PIV

为探讨混流式叶轮内部的流动机理,设计了一半开式叶轮混流泵实验装置,利用PIV技术对设计流量及变流量工况下叶轮内部的流动进行了测量。时均速度场的相对速度分布表明,设计流量下从进口到出口压力面附近相对流速先降低后升高,吸力面先升高后降低。在叶轮出口沿叶高方向压力面附近变化不大,吸力面从叶根到叶顶逐渐降低,最小相对流速位于吸力面叶顶附近。小流量工况下在叶顶和中间叶高截面内会出现回流现象,叶轮内不同流道内相对流速分布趋势基本一致。

A mixed-flow pump with unshrouded impeller was manufactured, and the flow in the impeller at design and off-design flow rates was measured by particle image velocimetry （PIV）. The distribution of time-averaged relative velocity showed the velocity near blade pressure surface at design flow rate decreased and then increased from inlet to outlet of the impeller, and that near blade suction surface increased and then decreased. At the impeller outlet, the relative velocity near blade pressure surface varied a little along the span direction; near the suction surface decreased from hub to casing, and the minimal velocity appeared near the casing and suction surface. Back-flow was found near casing and mid-span sections at partial flow rate. The velocity distribution in different impeller passages was similar.