倾斜均质表面上等径水滴聚合过程的可视化实验

EXPERIMENTAL INVESTIGATION ON COALESCENCE OF EQUAL-SIZE WATER DROPS ON INCLINED HOMOGENEOUS SURFACE

对倾斜均匀表面上等直径水滴的聚合过程及特性进行了可视化实验研究,获得了水滴直径和表面倾角等参数对液滴聚合过程中液滴液桥半径、接触角和接触线变化特性的影响,分析了水滴聚合对其运动的影响。实验结果表明:表面倾角越大,下滑的临界半径越小;液滴的直径越大,液滴聚合后越容易下滑;液滴聚合可以加快液滴的运动,使下滑临界半径减小。

Visual experiments were conducted for studying the phenomena and behaviors of the interfacial displacement during coalescence of two equal-size water drops on an inclined homogeneous surface. The variations of the bridge, the contact angle, and the contact line of drops with coalescence time were measured and the effects of drop size and inclination angle of surface on the coalescence and movement of water drops were analyzed. Experimental results showed that the detachment diameter of drop decreased with the increase of inclination angle of solid surface and the coalescence of two drops with larger size was benefic to cause the detachment of the coalesced drop. The liquid bridge radius and the contact angle of coalescing liquid drops with coalescence time behaved as a damped oscillation, generally. As the inclination angle of solid surface decreased, the oscillation frequency of the liquid bridge radius decreased, and the oscillation amplitude and the continued time of oscillation increased. A smaller drop had higher oscillation frequency, oscillation amplitude, and continued time of oscillation for the liquid bridge radius. The advancing contact angle of coalesced liquid drop after coalescing was significantly larger than the receding contact angle and the difference between the advancing contact angle and the receding contact angle decreased with the decrease of the drop size.