Dynamic behaviours of water droplets impacting on laser ablated surfaces
Dynamic behaviours of water droplets impacting on laser ablated surfaces
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DOI：
10.1016/j.colsurfa.2019.123743
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发表时间：
2019-11-05
影响因子：
5.2
通讯作者：
Qin, Yi
中科院分区：
文献类型：
--
作者：
Cai, Yukui;Luo, Xichun;Qin, Yi
为了揭示表面微观结构决定润湿态的内在机理，采用流体体积法(VOF)研究了低韦伯数和高韦伯数下水滴撞击不同结构表面的动力学行为。模拟结果表明，高压稳定的气囊压力是形成超疏水的关键。超疏水衬底与疏水衬底相比，水滴的回弹时间更短，反弹时间更长。此外，超疏水表面导致水滴的动能高于疏水表面，这是微结构自清洁功能的根本机制。对激光处理后的表面微结构进行了高速摄像试验，以验证动态冲击模拟中的观测结果。高速摄像测试和VOF模拟的结果都证明，水滴撞击超疏水表面时的粘附力要小于疏水表面。
In order to reveal the underlying mechanism of surface microstructure-determined wetting states, this paper adopted Volume of Fluid (VOF) method to investigate the dynamic behaviours of water droplets impacting on surfaces with different structures at low and high Weber numbers. The simulation results showed that the high and stable pressure of air pockets is critical for the formation of the superhydrophobicity. A superhydrophobic substrate will result in shorter recoiling time and longer rebound time for water droplet than the hydrophobic substrate. Furthermore, superhydrophobic surface resulted in higher kinetic energy for water droplet than hydrophobic surfaces, which is the underlying mechanism of microstructure-enabled self-cleaning function. High-speed camera tests of laser processed surface microstructures were conducted to validate the observation in dynamic impacting simulation. The results in both high-speed camera testing and VOF simulation proved that water droplet will have a lower adhesion force when impacting superhydrophobic surface than hydrophobic surface.