对置液柱撞击液膜破裂特征

Characteristics of breakup of liquid sheet of axisymmetric opposed jets

采用高速摄像仪对两液柱撞击产生液膜的破裂过程进行了实验研究。分析了撞击液膜的破裂过程及表面波产生和传播过程，考察了射流直径、喷嘴间距和射流Weber数（We）对撞击液膜破裂的影响；定量分析了液膜表面波频率的变化及液膜破裂后的粒径分布情况。研究结果表明，液膜表面波传播频率随 We 的增大而增大，并沿液膜径向方向逐渐减小；随着射流We的增加，液膜边缘的液滴脱落频率增加；当We＞1000时，液膜表面产生大量液滴团，且液滴团对液膜破裂具有促进作用；液柱撞击液膜发生破裂后90%以上的量纲1液滴粒径分布在0～1之间。

The breakup process of liquid sheet formed by two axisymmetric opposed jets was experimentally studied with a high-speed camera. The breakup process, the generation and propagation process of surface wave of liquid sheet were analyzed. The influences of jet diameter, nozzle separation and jet Weber number on the breakup of liquid sheet were investigated. The frequency variation of surface wave and the size distribution of sheet disintegration were quantitatively analyzed. The propagation frequency of surface wave increased with increasing We, but decreased along the radial direction. The droplet shedding frequency of sheet edge increased with increasing We. AtWe〉1000, a large number of droplet dots appeared at surface of liquid sheet, which promoted the breakup of liquid sheet. The non-dimensional drop size disintegrated from liquid sheet was mainly in the range of 0-1.