结构参数对高速液环泵内流场及水力性能的影响

The influence of structural parameters on the internal flow field and hydraulic performance of the high speed liquid-ring pump

为分析结构参数对高速液环泵内流场及水力性能的影响,采用数值模拟和试验相结合的方法,分析了某高速液环泵的排气口始端角、转速和偏心距等结构参数对泵内流场及外特性的影响。结果表明:随着排气口始端角的增大,进口真空度及效率均呈先增大后减小的趋势,排气口始端角为211°时性能达到最高;排气口始端角过小会导致排气口始端区域产生回流,排气口始端角过大会使泵排气不充分,传统设计方法得到的高速液环泵排气口始端角偏大,无法在进口形成真空度;随着转速的增大,液环内液体的做功能力增强,泵的进口真空度和吸气流量均逐渐增加,叶轮出口线速度低于15 m/s时泵进口无法形成真空度;随着偏心距的增大,进口真空度和最大吸气流量逐渐增大,但过大的偏心距会导致液环旋转不稳定,偏心距为3 mm时运行效果最佳。研究结果可为高速液环真空泵的设计提供参考。

In order to analyze the influence of structural parameters on the internal flow field and performance of the high speed liquid-ring pump,the influence of structural parameters of a high speed liquid-ring pump such as the exhaust port starting angle,rotational speed and eccentricity on the internal flow field and external characteristics were analyzed by the combined method of numerical simulation and experiment.The analysis results show that with the increase of the exhaust port starting angle,the inlet vacuum degree and efficiency increase first and then decrease,and the highest performance is achieved when the exhaust port starting angle is 211°.Too small exhaust port starting angle will lead to backflow in the initial area of the exhaust port,while too large exhaust port starting angle will make the pump exhaust insufficient.The starting angle of the exhaust port obtained by the traditional design method is a bit large,and the pump cannot form vacuum at the inlet.With the increase of the rotational speed,the power capability of the liquid in the liquid ring is enhanced,the inlet vacuum degree and flow rate of the pump gradually increase.When the linear velocity of the impeller outlet is lower than 15 m/s,the pump cannot form vacuum at the inlet.As the eccentricity increases,the inlet vacuum degree and maximal flow rate gradually increase,but too large eccentricity will cause the liquid ring to rotate unsteadily,and the operation effect is the best when the eccentricity is 3 mm.The research results can provide reference for the design of high-speed liquid ring vacuum pumps.