不同沙粒底面下气泡脉动特性实验研究

Experimental study of the interactions between a pulsating bubble and sand particles with different diameters

通过高速摄影系统对电火花气泡与不同沙粒底面间的相互作用进行了实验研究,并改变气泡与沙粒底面之间的距离.实验结果表明:气泡在与沙粒底面的相互作用中会产生两种明显不同的现象,即形成与近刚性壁面类似的气泡射流以及"蘑菇状"气泡,"蘑菇状"气泡撕裂形成两个气泡,随后产生两个反方向的沿轴线方向的射流.沙粒底面边界具有刚性与弹性两种特征.另外,随着气泡与沙粒底面之间的距离d的增大,气泡脉动周期先增大然后减小,存在气泡脉动周期峰值.对于不同的沙粒底面边界,出现气泡脉动周期峰值的距离d随着沙底粒径的增大而越小.

The interactions between a spark generated bubble and sand particles with different diameters are studied in this paper using a high speed camera. And distance between the bubble and sand particle is varied. The experimental results show that there are two distinct phenomena during the interaction between the bubble and sand particle. On the one hand, the jet formed is much like that near a rigid wall; on the other hand, a mushroom-shape bubble will form, which will split into two bubbles and two jets with opposite directions along the axes will be generated afterwards. Thus, it is found that the sand particle has the characteristics of a rigid wall and an elastic material. In addition, as the distance d between the bubble and sand particle increases, the pulsating period of the bubble will rise to a peak before it reduces. For different sand particles, the distance corresponding to the peak decreases as the diameter of sand particle increases.