复杂旋转回流PIV速度整场实验研究

Experimental investigation into swirling recirculating flow using PIV

复杂旋转回流流动的实验测量研究中,最受关注的是子午面上的速度分布,流动的复杂性对实验测量提出了较高要求,如测点数目多,对流场干扰限制严等。本文从PIV(粒子图象速度场测量)速度场测量技术的工作原理出发,分析了复杂旋转流动子午面上速度场测量中的双曝光时间间隔,示踪粒子的选取问题,得到了封闭圆柱空腔内旋转流动子午面上速度分布PIV实验测量速度场。实验测量结果可以清楚地观测到随着雷诺数的逐步增加,旋转流动流态的变化以及旋涡破裂现象的出现、发展以及消失的过程。

For experimental measurements of complicated swirling recirculating flow, velocity distribution in the meridional plane interests most researchers. However, the complication of this type of flow places much restriction on measurements, large number of measurement points, less interference of measurement instrument in flow, to name a few. As to measurement of swirling flows, the basic mechanism of PIV is firstly introduced, then the time between successive double exposures and the selection of treacking particles, are analyzed. For the confined swirling flow inside a cylindrical container with a rotating endwall, PIV measurement results of meridional velocity distribution are presented. The flow pattern dependent on Reynolds number is obvious from the obtained results, and the process of the appearance, development and disappearance of vortex breakdown with the increase of Reynolds number are clearly shown as well.