液体黏度对旋流泵性能和流动的影响

Influence of Liquid Viscosity on Performance and Flow Pattern for a Vortex Pump

采用计算流体力学方法研究比转速为76的定型产品32WB8-12型电机直联旋流泵输送水和不同黏度黏油时的水力性能和内部流动,分析液体黏度对性能曲线、泵水力损失、泵腔内部液体平均旋转角速度的变化,给出3个工况下流量、扬程、效率和叶轮圆盘摩擦损失修正系数与叶轮雷诺数的定量关系式,并与离心泵输送黏油试验数据和现有修正系数换算方法进行详细对比。结果表明:与离心泵相比,旋流泵的叶轮圆盘摩擦损失占轴功率的百分比最多为5%,属低叶轮圆盘摩擦损失泵;液体黏度对流量和效率修正系数影响较小,对扬程修正修正系数影响较大;当叶轮雷诺数不低于1×10~4时,旋流泵可维持较佳水力性能,适合输送黏度较高的液体;泵腔内存在环流涡,其位置和大小、液体平均角速度大小同黏度有关。

The hydraulic performance and flow in 32WB8 - 12 standard motor - connected vortex pump with a specific speed of 76 are studied by using CFD approach under water and viscous oil flow conditions. The variations of performance curve, hydraulic loss and dimensionless liquid angular velocity in the chamber in front of the impeller caused from increasing liquid viscosity are clarified. The flow rate, head, efficiency and impeller disc friction loss correction factors are correlated to impeller Reynolds number at three working conditions, respectively, these factors are compared with those of centrifugal pump carefully. Against centrifugal pumps, the impeller disc friction loss is only 5% of the shaft - power in the vortex pump in maximum, suggesting the pump belongs to a type of pump with a lower impeller disc friction loss. Liquid viscosity can demonstrate less effect on both flow rate and efficiency correction factors but more substantial influence on head correction factor. If the impeller Reynolds number is not smaller than 1 × 104 , the vortex pump can maintain a better performance, and be able to transport more viscous liquids than water. There is a re - circulating vortex in the meridi-an plane of the chamber, and its position, size and mean liquid rotating angular velocity in the chamber depend on liquid viscosity.