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本文论述低比转数离心泵特性曲线的稳定性。尽管能够从理论上对离心泵的几何形状及其对扬程流量特性曲线的影响之间的关系予以论述,但是十分明显,泵内的流场在流量下降的时候是非常复杂的,而且不能够单单通过理论来加以解释。泵的几何形状和部分流量是产生泵内二次回流的基本原因。试验证明了引起杨程流量特性曲线下跌的二次回流的确实存在。减小这种二次回流,就能够使消耗于这种流动上的能量用来增加泵的总扬程,从而可以提高泵的特性曲线的稳定性。泵的入口尺寸形状起着重要作用,人们一直在对其影响进行着详尽的研究。叶轮的叶片向叶轮吸入口部位延伸,而后又逐渐缩短。人们发现,伸展得最长的叶轮叶片对于改善泵特性曲线的稳定性是非常有效的,而这种效果与叶轮的叶片形状是单曲率或是双曲率无关。如果在叶轮的吸入口内放置一组静止的导向叶片,也可以观察到类似的效果。对叶轮的叶片数、出口角和直径比的影响也进行了研究,并且所得的实验结果与理论一致。
This article discusses the stability of the low specific rotation centrifugal pump characteristic curve. Although the relationship between the geometry of the centrifugal pump and its effect on the headflow characteristic can be theoretically discussed, it is quite clear that the flow field inside the pump is quite complicated at the time of the drop in flow and can not be handled in a single By theory to explain. Pump geometry and part of the flow rate is the secondary cause of secondary pump backflow. The experiment proves the existence of the secondary backflow that caused the drop of the flow characteristic curve of Yang process. Reducing this secondary back-flow allows the energy consumed in this flow to be used to increase the overall head of the pump, thereby increasing the stability of the pump’s characteristic curve. The size and shape of the pump inlet plays an important role, and people have been studying it in great detail. The impeller blades extend to the impeller inlet and then gradually shorten. It has been found that the most prolonged impeller blades are very effective in improving the stability of the pump characteristic curve and this effect is independent of whether the blade shape of the impeller is a single curvature or a double curvature. A similar effect can be observed if a set of stationary guide vanes are placed in the suction port of the impeller. The influence of the impeller blade number, exit angle and diameter ratio was also studied, and the experimental results obtained are consistent with the theory.