低比转速泵叶轮流道内部流动的PIV试验

介绍了粒子图像测速仪(PIV)、泵试验装置和试验方案.采用PIV技术,对3种流量下叶轮流道内部3个不同测量平面上的流动进行了试验研究,获得了速度矢量分布.探讨了速度分布沿叶轮周向和轴向的变化规律以及流量对速度分布的影响.结果表明,随着流量的减小,吸力面速度略有减小,压力面速度变化较为明显,当流量达到额定流量的0.6倍时,在压力面附近存在回流现象;在叶轮出口处,流量对相对速度方向没有明显影响;叶轮流道内部速度沿轴向分布均匀,绝对速度沿半径方向呈增加趋势,无量纲绝对速度的周向分量v_u/v从压力面到吸力面呈下降趋势,且随流量的减小而增大.研究结果为叶轮设计以及离心泵内部流动的试验研究提供了借鉴. 

Experimental study on flow in the impeller of low specific speed pump using particle image velocimetry

Particle image velocimetry(PIV) system,pump experimental facility and test scheme were introduced.An experimental investigation of flow in the impeller was conducted at three different flow rates on three measurement planes by means of PIV.The velocity vector distribution was obtained.The velocity distribution in circumferential and axial directions and the influence of flow rate on the distribution were investigated.The results indicate that,the velocity near the suction surface decreases slightly,and that near the pressure surface changes dramatically with decreasing flow rate.The fluid flows back near the pressure surface when the flow rate reaches 0.6Q_d.At the outlet of impeller,the flow rate has no significant influence on the direction of relative velocity.The velocity in the impeller passage distributes homogeneously in axial direction.The absolute velocity shows an increasing trend in radial direction.The circumferential component of nondimensional absolute velocity decreases from the pressure surface to the suction surface,and also increases with the decline of flow rate.The results provide valuable information for the design of impeller and experimental study on flow in the centrifugal pump.