叶片包角对高比转速离心泵水力性能的影响研究

Effect of blade wrap angle of high specific speed centrifugal pump on hydraulic performance

高比转速离心泵流道宽大,包角的大小将直接影响其水力性能。基于N-S方程和RNG k-ε湍流模型,对5种不同的叶片包角模型在多种工况下分别进行了数值模拟计算分析,以对不同包角下的外特性变化趋势、叶轮内部的三维流线以及湍动能变化规律进行研究。研究结果表明:(1)随着叶片包角的增大,离心泵的最高效率点表现为先增加后减小,扬程随着流量的增大而下降,当包角增大到一定限值时,下降的幅度最为明显;(2)离心泵叶轮流线在相同的流量下,随着叶片包角的增大,流线愈发平顺光滑且越趋于叶片线型时,叶轮的总压随包角的增大而逐渐减小;(3)在设计工况下,低速区主要集中在叶轮进口的叶片工作面处,随着叶片包角的增大,湍动能逐渐减小;(4)当叶片包角在110°附近时,该泵的水力性能即达到最优。研究结果可为今后对高比转速离心泵的研究提供一定的参考。

High specific speed centrifugal pump has large flow channel. Its blade＇s wrap angle directly affects its hydraulic performance. Based on N-S equation and the RNG k-ε turbulence model,five pump models of different blade＇s wrap angle were numerically simulated under multiple conditions to study the variation trend of external characteristics,the variation laws of three-dimensional flow line and turbulent kinetic energy inside the impeller. The results showed：（1） With the increase of the angle,the highest efficiency point of centrifugal pump firstly increase and then decrease; lifting height decrease with the increase of flow rate and decrease most obviously when the angle reaches a limit value;（2） For the same flow rate,with the increase of the angle,the blade streamline become smoother,more close to the blade line type,and the total pressure of the impeller decrease;（3） in the designed condition,low-speed area mainly concentrated in flowing face of blade at impeller inlet,with the increase of the angle,turbulent kinetic energy decrease gradually;（4） Pump＇s hydraulic performance reaches the highest when the wrap angle is around 110 °. The research results can provide reference for the future research of high specific speed centrifugal pump.