论文标题
液滴对液体池的撞击期间的腔变形和气泡夹带
Cavity deformation and bubble entrapment during the impact of droplets on a liquid pool
论文作者
论文摘要
液滴对液体池的影响本质上是普遍存在的，在许多工业应用中很重要。在某些撞击条件下，对液体池撞击的液滴会导致常规气泡的捏合或捕获大气泡。在这项研究中，通过合并的实验测量和数值模拟研究了液滴对液体池的影响的空腔变形和气泡夹带。在数值模拟中获得的自由表面轮廓的时间演变与实验结果非常吻合。液滴冲击产生的腔会影响常规气泡的捏合和大气泡的夹带。常规的气泡捏是沿腔界面向下传播并在腔底部合并的毛细管波的直接结果。相比之下，大气泡夹带是由于液体牙齿在腔口中的融合所致。重力和环境压力在液滴对液体池的影响后在腔变形和气泡夹带中起重要作用。随着重力效应的强度，腔的最大深度减小。随着重力降低，常规气泡捏合的现象可能会消失。我们发现，在增加环境压力时，常规的气泡捏合可以转变为大气泡夹带。大气泡的大小随着较大的压力差异和液体牙冠周围的涡度差异在增加的环境压力下，随着环境压力的增加而减小。最后，获得液滴冲击后气泡夹带的制度图。
The impact of droplets on a liquid pool is ubiquitous in nature and important in many industrial applications. A droplet impacting on a liquid pool can result in the pinch-off of a regular bubble or entrap a large bubble under certain impact conditions. In this study, the cavity deformation and the bubble entrapment during the impact of droplets on a liquid pool are studied by combined experimental measurements and numerical simulations. The time evolution of the free surface profile obtained in the numerical simulation is in good agreement with the experimental results. The cavity created by the droplet impact affects the pinch-off of regular bubbles and the entrapment of large bubbles. The regular bubble pinch-off is the direct consequence of the capillary wave propagating downward along the interface of the cavity and merging at the bottom of the cavity. In contrast, the large bubble entrapment is due to the merging of the liquid crowns at the mouth of the cavity. Gravity and environmental pressure play important roles in cavity deformation and bubble entrapment after droplet impact on liquid pools. The maximum depth of the cavity decreases as the gravitational effect becomes stronger. The phenomenon of regular bubble pinch-off may disappear as the gravity decreases. We find that the regular bubble pinch-off can transform into large bubble entrapment when increasing environmental pressure. The size of the large bubble entrapped decreases with increasing the environmental pressure due to the larger difference in the pressure and the vorticity around the liquid crown at increased environmental pressure. Finally, the regime map of bubble entrapment after the droplet impact is obtained.
