粘度对离心泵蜗壳内部流动的影响

Effects of Viscosity of Liquid on the Flow in Volute of a Centrifugal Pump

利用 L DV分别测量了离心泵最优工况和小流量工况下矩形断面蜗壳内 3个断面的清水和粘油平均流动。试验表明 ,蜗壳内部液体绝对速度的圆周分速度比径向分速度大一个数量级 ;蜗壳断面内存在旋向相反的一对旋涡 ;液体粘度越大 ,蜗壳内部流动越不均匀 ;蜗壳断面内流体角动量不守恒 ,液体粘度越大 ,角动量越不守恒 ;最优工况和小流量工况时 ,蜗壳内部流动都是扩散流动 ;液体粘度越大 ,流动扩散越小。

The flows of water as well as viscous oil in three sections of a centrifugal pump volute are measured by using two dimensional laser Doppler velocimeter(LDV) at optimum operating condition and partial loading points, respectively. The results show that magnitude of tangential velocity component of absolute velocity is larger one order than that of radial component. There are second flows with spiral motion in opposite direction in the sections of the volute. The velocity of liquid is uneven and the angular moment in the volute isn't conservative. With the viscosity of liquid getting higher, this situation is more seriously. The flow of water or viscous oil in the volute is diffused at optimum operating condition and partial loading points. However, the diffusion of the flow is weakened while pumping the viscous oil.