粒子图像测速实验在离心泵流体力学教学中的应用及实例展示

APPLICATION OF PIV EXPERIMENT IN FLUID MECHANICS TEACHING OF CENTRIFUGAL PUMP AND DEMONSTRATION OF EXAMPLES

离心泵是流体力学理论最为典型的应用,很多流体力学教材都将离心泵列为重要章节。离心泵输送单一介质时内部流体是圆周运动和相对运动的复合运动,输送固液两相时还会存在两相速度差,可见其内部流动非常复杂。如果将这些复杂的流体运动可视化,让学生看到这种流动现象,将会成为理论教学非常好的补充,加强学生对课堂知识的理解和巩固。为了将内部流动更好地呈现出来,本实验台将离心泵透明可视化,再做了局部改造后,叶轮和蜗壳区域可全部无遮挡地展现出来,再利用粒子图像测速技术捕捉内部流动,在宏观方面来讲,可开展单一介质或者两相介质在叶轮中的流动情况的观察实验,在微观方面来讲,可开展观察单一介质速度场和两相介质相对速度的测量实验。

Centrifugal pump is one typical application of fluid mechanics theory. Many textbooks for fluid mechanics include centrifugal pump as an important chapter. When conveying a single medium, the flow in the pump is the compound movement of circular motion and relative motion. When conveying the solid-liquid twophase, there is also a velocity difference between the two phases, hence the internal flow is very complicated. If these complex fluid movements can be visualized to demonstrate flow pattern, it will be a very good supplement to theoretical teaching, which will strengthen students understanding and consolidate classroom knowledge. For better visualize the internal flow, the pump and pipelines are made of transparent material, hence the impeller and volute area can be viewed without obstruction. Using particle image velocimetry(PIV) technology to capture the internal flow, a single medium or two-phase medium flow can be observed in the impeller observation experiment from a macroscopic perspective, velocity field of single medium and the relative velocity of two-phase medium can be measured locally.