叶片包角对高比转速离心泵水力性能的影响研究

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。

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

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.