壁面吸附复合液滴的变形与运动特性

Deformation and Motion of Compound Droplet Adhering to Wall

流动作用下壁面吸附复合液滴可呈现不同的动力学状态,了解其动力学状态转变及参数影响规律是操控液滴运移的关键.本文基于Front-tracking Method结合广义Navier边界条件建立了能够模拟移动接触线问题的数值方法。主要考察了层液滴毛细数、内层液滴大小、内层液滴毛细数对接触角滞后壁面吸附复合液滴动力学特性的影响。研究发现:外层液滴毛细数越大、内层液滴毛细数越小且内层液滴体积越大,复合液滴更容易从壁面脱附或被流体剪切发生破碎.

The compound droplet will exhibits much more complex behavior when it adheres to a wall under flow. Studying the influence of related parameter plays an important role in the manipulation of the compound droplet. In this paper, a three-dimensional numerical method involving the moving contact line problem is developed by integrating the generalized Navier boundary condition into the front-tracking method. The proposed method is applied to study the effects of the capillary munber of inner and outer interface and the volume of inner droplet on the deformation and motion of the compound droplet adhering to the wall with considering the contact angle hysteresis effect. It found that the compound droplet is more like to be detached or pinched-off by the flow when the capillary number of outer interface and the volume of inner droplet are large and the capillary number of inner interface is small.