椭球液滴撞击超疏水表面反弹过程数值分析  

Numerical analysis of rebound process of ellipsoidal droplets impact on superhydrophobic surface

作　　者：涂德浴[1] 潘庆民 童宝宏[1] TU De-yu;PAN Qing-min;TONG Bao-hong(School of Mechanical Engineering,Anhui University of Technology,Maanshan 243032,China)

机构地区：[1]安徽工业大学机械工程学院,马鞍山243032

出　　处：《计算力学学报》2021年第2期215-221,共7页Chinese Journal of Computational Mechanics

基　　金：国家自然科学基金(51975005,51975174,51875152,51875154);安徽省自然科学基金(2008085ME148,1908085QE195)资助项目.

摘　　要：液滴在自由落体或受外力作用时常发生椭球形变,对其撞击超疏水壁面的运动形态及形成二次液滴有较大影响。本文假定具有不同轴向半径比值(AR)的椭球形液滴,采用耦合水平集-体积分数(CLSVOF)方法对椭球形液滴撞击超疏水平壁面进行数值模拟研究,对椭球形液滴撞击超疏水平壁面反弹过程运动形态和AR对二次液滴形成的影响进行分析。研究表明,不同AR液滴撞击超疏水壁面后反弹过程具有一定相似性,同时存在明显差异。液滴反弹过程中会拉伸形成长液柱,其未扰动界面直径随AR的增大而减小。在Plateau-Rayleigh不稳定性影响下,长液柱会发生破碎形成二次液滴,但较低的AR对二次液滴的形成有较明显的抑制作用,当AR小于临界值0.6时,反弹过程中液滴内部压力均匀稳定,最终不产生二次液滴。Droplets often change into an ellipsoid shape when they are in free fall or under the action of an external force,which has a great influence on the motion form of impacting the super-hydrophobic wall and the formation of secondary droplets.This paper assumes that ellipsoidal droplets with different geometric aspect ratios(ARs)appear.The rebound process of an ellipsoidal droplet after impacting on the super-hydrophobic wall is studied by using the coupled Level Set-VOF method for gas-liquid interface tracking and the effect of AR on the formation of secondary droplets is also analyzed.The research shows that the rebound process of ellipsoidal droplets with different AR has certain similarities while there are obvious differences in some details.The droplets will stretch to form a long liquid column during the rebound process,the diameter of the undisturbed interface decreases with the increase of ARs.Under the influence of Plateau-Rayleigh instability,the long liquid column will break up to form secondary droplets,but the low ARs can significantly inhibit the formation of secondary droplets.When the AR is less than the critical value of 0.6,the internal pressure of the droplets is uniform and stable,and no secondary droplets are eventually generated during the rebound process.

关 键 词：椭球液滴碰壁 超疏水表面 计算流体力学 二次液滴 

分 类 号：O35[理学—流体力学] O302[理学—力学]