3D simulation of micro droplet impact on the structured superhydrophobic surface
3D simulation of micro droplet impact on the structured superhydrophobic surface
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DOI：
10.1016/j.ijmultiphaseflow.2021.103887
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发表时间：
2022-02-01
影响因子：
3.8
通讯作者：
Liu, Dong
中科院分区：
文献类型：
--
作者：
Hu, Anjie;Liu, Dong
采用VOF模型对微液滴在大范围冲击速度下冲击超疏水结构表面的过程进行了数值研究。给出了Cassie和Wenzel两种状态下的液滴碰撞过程，并进行了讨论.在模拟中还研究了固有接触角和柱体高度对碰撞的影响。模拟结果表明，由于微液滴直径较小，拉普拉斯压力对液滴碰撞的影响不可忽略，这有利于Cassie碰撞区的穿透转变。具有较大内禀接触角的表面不仅可以降低Cassie冲击的穿透深度，而且可以显著降低Wenzel冲击区域中表面的粘附力。当固有接触角大时，液滴甚至在Wenzel冲击状态下也可以回弹。柱体的高度也影响液滴在Wenzel区域中的弹跳能力。较短的柱体有利于液滴在Wenzel碰撞区域中的反弹，而不利于维持Cassie区域。研究结果可为理解高速过冷液滴撞击防冰超疏水表面的机理和设计高效防冰表面提供参考。
In this work, the volume-of-fluid (VOF) model is applied to numerically study the micro droplet impact on the structured superhydrophobic surface with a large range of impact velocity. The droplet impact processes of both Cassie and Wenzel regimes are obtained and discussed. The influences of the intrinsic contact angle and pillar height on the impact are also studied in the simulation. The simulation results show that, due to the small diameter of the micro droplet, the effect of the Laplace pressure on the droplet impinging cannot be neglected, which could facilitate the impalement transition in the Cassie impact regime. The surface with a larger intrinsic contact angle can not only reduce the penetrate depth of the Cassie impact, but also significantly reduce the adhesion force of the surface in the Wenzel impact regime. When the intrinsic contact angle is large, the droplet can rebound even in the Wenzel impact regime. The height of the pillar also influences the bouncing ability of the droplet in the Wenzel regime. A shorter pillar is beneficial for droplet bouncing in the Wenzel impact regime while it is bad for maintaining the Cassie regime. These results can be used as a reference in understanding the mechanism of high-speed supercool droplet impact on anti-icing superhydrophobic surface and designing highly efficient anti-icing surfaces.