自吸泵内能量损失及非定常流动特性研究

自吸泵由于其特有的气液分离腔和回流孔结构使得其内部流动更为复杂,本文针对自吸泵内能量损失及非定常流动特性开展实验和数值研究。通过开展模型泵水力性能实验,发现数值计算结果与实验结果具有较好一致性。利用熵产理论和Q准则定量分析了不同工况下自吸泵内不同区域的能量损失特性及涡核分布特征,结果表明:泵内熵产分布特征与水力损失分布特征基本一致,叶轮、蜗壳和气液分离腔是自吸泵内能量损失的主要区域。蜗壳内部的压力脉动强度在靠近隔舌区域较大,蜗壳中段处变弱,蜗壳出口扩散段处又进一步增强。在小流量工况下,叶轮和蜗壳内部涡核分布面积较大,涡核主要分布在叶轮的进口处和出口处。

Energy loss and unsteady flow characteristics in a self-priming pump

Internal flow of self-priming pump is more complex due to its gas-liquid separation chamber and recirculation hole features. In this paper, the energy loss and unsteady flow structures of a self-prim-ing pump is investigated experimentally and numerically. It is found that the calculation data has a good consistency with the test data. The entropy production theory is used to analyze the energy loss of individu-al parts of self-priming pump and the Q criterion is selected to evaluate the vortex cores inside the pump under different conditions,separately. The results show that the distribution characteristics of entropy produc-tion rate in the pump are basically consistent with the distribution characteristics of hydraulic loss. The im-peller, volute and gas-liquid separation chamber are the main areas of energy loss in the self-priming pump. The pressure pulsation amplitude of volute is larger near the tongue area,and it is decreased in the middle sections of volute,afterwards,it is further strengthened in the diffusor section. Under part-load con-dition,the distribution of vortex cores inside the impeller and volute is large,and the vortex core is main-ly distributed at the inlet and outlet of impeller.