液滴撞击不同固体表面的数值模拟研究

采用CLSVOF(coupled level set and volume of fluid)方法,对低We情况下液滴撞击不同固体表面的过程进行了数值模拟研究。分析了液滴撞击平板表面的动态过程,构建了液滴衰减振荡的数学模型,探究了不同的表面润湿性、撞击速度及表面微尺度结构对液滴动态特性的影响。结果表明:液滴撞击固体表面的过程包含铺展、回缩、振荡等多个现象,其最大铺展因子及振荡周期随着表面接触角的增大而减小,随着撞击速度的增大而增大;撞击表面的微尺度结构会对液滴的动态特性产生影响,微尺度结构会对液滴的铺展及回缩运动产生阻碍作用,导致液滴的振荡特性减弱;液滴在矩形沟槽表面达到最大铺展因子的用时最短,在三角形沟槽表面的最大铺展因子最小。

Numerical simulation study of droplet impact on various solid surface

The behavior of droplet impact on different solid surface under low Weber number is simulated with the CLSVOF (coupled level set and volume of fluid) method. Dynamic behavior of droplet impact on plane surface is analyzed and mathematical model of damped oscillation is established. Different surface wettability, impact velocity and micro-scale structure on solid surface are investigated. Simulation results show that the dynamic process of dropet impact on solid surface is formed by spreading, retraction, oscillation phenomenon and so on. The maximum spreading factor and oscillation period decrease with increasing contact angle, and they increase with increasing impact velocity. The micro-scale structure on impact surface has a great effect on dynamic characteristics of droplet. It is a resistance to spreading and retraction of droplet, and weaken the oscillation characteristics. The time needed to arrive at the maximum spreading factor is smallest for rectangle groove surface. The maximum spreading factor is smallest for triangle groove surface.