液滴在亲水表面快速铺展过程中的溅射现象

Ejection Phenomenon of Droplets During the Fast Spreading on a Hydrophilic Surface

采用格子Boltzmann方法,建立了液滴在亲水固体表面上快速铺展过程的三维非稳态理论模型。研究了液滴铺展的动态过程,分析了液滴的形貌变化,比较了固体表面润湿性和液滴的运动黏度对液滴铺展过程的影响,获得了溅射现象产生的原因。研究结果表明,液滴接触到亲水固体表面后,从底部产生的毛细波是造成液滴颈部断裂和溅射现象的主要原因;固体表面的接触角越小,液滴铺展的速度越快,越容易产生溅射现象;黏性力在铺展过程中起到减缓液滴铺展的作用,液滴的运动黏度越大,越难产生溅射现象。

The three-dimensional unsteady theoretical model of the droplet fast spreading process on a hydrophilic solid surface was developed by the lattice Boltzmann method. The dynamic process of the droplet spreading was researched, and the morphology change of the droplet was analyzed. The effects of the solid surface wettability and droplet kinematic viscosity on the droplet spreading process were compared, and the causes of the ejection phenomenon were obtained. The research results indicate that after the droplet comes into contact with the hydrophilic solid sur- face, the capillary wave generated from the bottom of the droplet is a main cause for the droplet neck fracture and ejection phenomenon. The smaller the contact angle on a solid surface is, the faster the velocity of the droplet spreading is, and the more easily the ejection phenomenon generates. The viscosity force slows down the droplet spreading. The larger ty of droplet is, the more difficultly the ejection phenomenon generates.