Self-driven penetration of droplets into non-wetting capillaries
Self-driven penetration of droplets into non-wetting capillaries
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DOI：
10.1016/j.compfluid.2017.06.006
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发表时间：
2017-09
影响因子：
2.8
通讯作者：
Yuxiang Wang;Shuo Chen;Bisheng Wu
中科院分区：
文献类型：
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作者：
Yuxiang Wang;Shuo Chen;Bisheng Wu
这是我们之前在该杂志上发表的研究的后续研究。本文采用多体耗散粒子动力学（MDPD）对液滴在非润湿毛细血管中的渗透进行了进一步的数值研究。模拟结果表明，液滴的外（毛细外）曲率和内（毛细内）曲率会产生两个拉普拉斯压力。这两个压力之间的差形成一个净推力，直接驱动液滴流入非润湿毛细管。我们详细分析了外曲率和内曲率在侵彻过程中的变化规律。为了进一步证明拉普拉斯压差对液滴运动的影响，我们还模拟了一个新的液滴/毛细/膜系统。在该系统中，液滴和液膜被放置在预填充毛细管的两端。非常有趣的是，液滴在疏水毛细血管中的渗透速度比在亲水毛细血管中的渗透速度更快，而且这种自发渗透不存在任何润湿性限制，这与以往文献的研究不同。本研究有望为利用液滴本身的驱动力设计微流控或纳米流控器件提供新的思路。
This is a successive study to our previous study published in this journal. In the present study, a further numerical study on the penetration of a droplet into non-wetting capillaries is carried out by using many-body dissipative particle dynamics (MDPD). The simulation results show the outer (outside of the capillary) and inner (inside of the capillary) curvatures of the droplet can cause two Laplace pressures. The difference between these two pressures forms a net pushing force which directly drives the droplet flowing into the non-wetting capillary. We give a detailed analysis on how the outer and inner curvatures change during the penetration process. To further show the effect of the Laplace pressure difference on the droplet movement, we also simulate a new droplet/capillary/film system. In this system, the droplet and liquid film are placed at both ends of a prefilled capillary. It is very interesting to find that the droplet penetrates even faster in lyophobic capillaries over lyophilic ones, and the spontaneous penetration does not pose any wettability restriction which is different from previous study in literatures. The present work is expected to provide new ideas for designing microfluidics or nanofluidics devices by utilizing the driving force from the droplet itself.