连接柱处理对圆盘泵性能及内部流场影响研究

Study on effect of connecting column treatment on performances and internal flows in disc pumps

本文总结圆盘泵数值模拟方面的研究,对圆盘泵连接柱区域设置了两种不同的模型方案进行数值模拟。分析了不同流量工况下圆盘泵性能及叶轮内部流场变化,并对计算结果进行验证。结果表明:方案一连接柱两侧出现明显低速区域,方案二由于连接柱周围水体旋转,因此区域速度值更大。两种方案均在叶片吸力面位置出现局部低压,因此圆盘泵内湍动能耗散主要出现在叶片及其吸力面侧,而在进、出口能量耗散较小。流体流过连接柱之后,方案二的圆周速度和绝对速度圆周分量均小于方案一,表明了圆盘泵实际运行过程中,连接柱对出口流动的阻碍作用产生的损失大于其带来的能量,导致方案二的扬程低于方案一。两种方案的计算结果与试验结果变化趋势一致,同时两种方案之间的差异较小,如果仅考虑快速计算圆盘泵性能,方案一在模型处理上更简单高效。如果要获得更全面准确的内部流动信息,方案二的内部流动情况更接近实际情况。

This paper presents a numerical simulation study on a disc pump in two different model scenarios of its connecting column region.The performance and the change in the flow inside the impeller under different flow conditions are examined and the calculations are verified with experimental measurements.Comparison of the calculations in the two schemes shows that in Scheme I,a significant low velocity region occurs on both sides of the connecting column,while in Scheme II,the local velocity is higher due to the set-up of near wall fluid.In the two schemes,local low-pressure areas occur on the blade suction surface,and the formed vortices also result in an increase in local energy dissipation.Therefore,most of the turbulent energy dissipation in the pump is concentrated on the blade suction surface,while energy dissipation near the pump inlet and outlet are weak.After the flow passes through the connecting column,its circumferential velocity and the circumferential component of its absolute velocity in Scheme II are smaller than those in Scheme I.This indicates that in pump operation,the energy loss generated by the blocking effect of the connecting column on the outlet flow is greater than the amount of energy brought by the column itself,resulting in a lift head lower in Scheme II than Scheme I.The calculations of the two schemes agree with the trends measured in the experiment,and the performance differences between them are rather small.Schemes I is simpler and efficient if only the rapid calculation of pump performance is considered;Scheme II is preferred if comprehensive and accurate information of internal flow is needed.