回流孔径对磁力驱动离心泵内部流动的影响分析

Analyzing the Impact of the Diameter of Return-flowing Valve on Flow Field in Magnetically-driven Pump

为研究回流孔径变化对磁力驱动离心泵内部流场及水力性能的影响,分别以6、8、10 mm等3种不同回流孔径的磁力驱动离心泵模型,通过定常、非定常以及流热耦合等数值计算与外特性试验相结合的方法,开展了回流孔径变化对磁力驱动离心泵外特性、内部流场、温度场以及压力脉动特性的影响规律研究。结果表明,(1)回流孔径的变化对磁力驱动离心泵的扬程、效率及泵内部流场的影响较小,其中随着回流孔径的增大,磁力驱动离心泵扬程及效率呈下降趋势;(2)回流孔径的变化对冷却循环流道内的流场、温度场以及压力脉动性能的影响较大,其中随着回流孔径的增大,冷却循环流场内的压力分布逐渐减小,湍动能分布呈增大的趋势,冷却循环流道的冷却效果逐渐变强,另外回流孔径变化对传播进入冷却循环流场的压力脉动强度影响较小,对冷却循环流场内的压力脉动衰减速度影响较大。综上可知,回流孔径变化对泵内流场的影响较小,对冷却循环流道内的流动特性影响较大。

The effects of the diameter of return-flowing valve onflow field and hydraulic characteristics in magnetic pump were numerically studied in this paper.We examined three diameters：6 mm,8 mm and 10 mm.The internal flow,temperature and pressure distributionsin the pump were numerically simulated under both steady an unsteady conditions with consideration of heat-fluid coupling.The results showed that the change in return-flowing valve diameter had only a minor impact on lift height and efficiency of the pump as well as the flow field,although the lift height and efficiency decreased with the increase in the diameter.Under cooling condition,however,a change in the return-flowing valve diameter could significantly impact flow and temperature fields,as well as pressure fluctuation in the pump.With increase in the diameter,the kinetic energy distribution and cooling efficiency increased,while the pressure distribution decreased.In addition,the diameter of the return-flowing valve had little effect on pressure fluctuation intensity of cooling circulation fluid,but it had a great effect on the release velocity of pressure fluctuation in cooling circulation fluid.Overall,the changes of reflowing valve had a great effect on the flow characteristic of cooling circulation fluid,and have minimal effect on the flow characteristic of magnetic drive pump.