不混溶液体表面上蒸发液滴的动力学特性

针对不混溶均匀受热液体表面上蒸发液滴的动力学过程,基于润滑理论推导出了无量纲方程组。采用数值模拟方法,探究了蒸发液滴的动力学特性。结果表明,蒸发液滴的演化过程分为两个阶段:由"铺展主导"的液滴前进阶段和由"蒸发主导"的持续脉动振荡的后退阶段。液滴在低黏度比下的流动性更强,导致铺展更加迅速,黏度比的增加会导致铺展和收缩速率的降低。蒸发通过影响液滴界面的温度分布进而影响界面张力以及液滴铺展。相较于固体表面液滴蒸发出现的钉扎现象,蒸发液滴在不混溶液体表面上的铺展是去钉扎的,并且伴有液体基底的明显变形。

Dynamics of volatile drop on surface of another immiscible liquid

Aiming at the dynamic process of evaporated droplets on the surface of immiscible and uniformly heated liquid, a set of dimensionless equations are derived based on the lubrication theory. The dynamic characteristics of evaporated droplets were studied by numerical simulation. The results show that the evolution process of the droplets can be divided into two stages: the advancing stage of the droplets dominated by spreading and the backward stage of the continuous fluctuating oscillation dominated by evaporation. The fluidity of droplets is stronger at low viscosity ratio, which leads to more rapid spreading. The increase of viscosity ratio will lead to the decrease of spreading and shrinkage rate. Evaporation affects the interfacial tension and droplets spreading by affecting the temperature distribution of the droplets interfaces. Compared with the pinning phenomenon of drop evaporation on the solid surface, the spreading of evaporated droplets on the immiscible liquid surface is depinned and accompanied by obvious deformation of the liquid substrate.