Zhang Aiping, Cui Kai, Tian Yuanyuan, Zhang Benxi, Wang Tieying, He Xin
School of Mechanical Engineering, Northeast Electric Power University, Jilin City 132012, China.
Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China.
J Chem Phys. 2024 May 7;160(17). doi: 10.1063/5.0205763.
The impacting phenomenon of nanodroplets has received much attention due to their importance in various industrial applications. The oblique impingement of single droplets is well understood; however, the effect of oblique angle on impacting the dynamics of multiple droplets at the nanoscale is very limited. To address this gap, we perform molecular dynamics (MD) simulations to study the impacting dynamics of binary nanodroplets with various oblique angles (αob) and Weber numbers (We). Using MD simulations, we directly capture the detailed morphological evolution of the impacting binary droplets with various given conditions. Compared to the oblique impingement of a single droplet, the evolution of impacting binary droplets involves two novel dynamic characteristics: the asymmetric dynamics with droplet preferential spreading in the y direction and the rotating of the coalescing droplet. The mechanisms underlying are well studied. The asymmetric dynamics is a result of the velocity gradient of the outer edge of the spreading droplet, and the rotating effect is due to the change in angular momentum induced by surface force. The analysis and study of these phenomena have never been mentioned in previous studies of single droplet. Finally, we investigate the effect of αob and We on normalized moving distance (L/Dsin) and contact time (tc). This work paves the way for offering a comprehensive understanding of the oblique impingement of binary nanodroplets.
纳米液滴的撞击现象因其在各种工业应用中的重要性而备受关注。单个液滴的斜向撞击已得到充分理解；然而，在纳米尺度下，倾斜角度对多个液滴撞击动力学的影响非常有限。为了填补这一空白，我们进行了分子动力学（MD）模拟，以研究具有不同倾斜角度（αob）和韦伯数（We）的二元纳米液滴的撞击动力学。通过MD模拟，我们直接捕捉了在各种给定条件下撞击二元液滴的详细形态演变。与单个液滴的斜向撞击相比，撞击二元液滴的演变涉及两个新的动态特征：液滴在y方向优先铺展的不对称动力学以及合并液滴的旋转。其潜在机制已得到充分研究。不对称动力学是铺展液滴外边缘速度梯度的结果，而旋转效应是由表面力引起的角动量变化所致。这些现象的分析和研究在以前的单液滴研究中从未被提及。最后，我们研究了αob和We对归一化移动距离（L/Dsin）和接触时间（tc）的影响。这项工作为全面理解二元纳米液滴的斜向撞击铺平了道路。
