A Many-Body Dissipative Particle Dynamics Study of Spontaneous Capillary Imbibition and Drainage
A Many-Body Dissipative Particle Dynamics Study of Spontaneous Capillary Imbibition and Drainage
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DOI：
10.1021/la100105f
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发表时间：
2010-06-15
期刊：
影响因子：
3.9
通讯作者：
Lu, Juntao
中科院分区：
文献类型：
--
作者：
Chen, Chen;Gao, Chunning;Lu, Juntao
利用多体耗散粒子动力学（MDPD）模拟研究了自发毛细吸收和排泄过程。通过调节固 - 液相互作用参数，可以可控地模拟流体与毛细管壁之间不同的润湿行为，其对应的静态接触角范围从0到180度。对于润湿流体，在MDPD模拟中自发毛细吸收（SCI）是明显的。研究发现，尽管修正的卢卡斯 - 沃什伯恩方程（考虑了动态接触角和流体惯性）能够很好地描述完全润湿流体的SCI模拟结果，但它在很大程度上偏离了部分润湿流体的结果。特别是，这个修正方程不能用于描述自发毛细排泄（SCD）过程。为了解决这个问题，我们推导了卢卡斯 - 沃什伯恩方程的一种改进形式，其中考虑了流体粒子在毛细管壁处的滑移效应。这种改进的方程能够描述SCI和SCD的所有模拟结果。这些发现为SCI和SCD过程提供了新的见解，并完善了数学基础。
The spontaneous capillary imbibition and drainage processes are studied using many-body dissipative particle dynamics (MDPD) simulations. By adjusting the solid-liquid interaction parameter, different wetting behavior between the fluid and the capillary wall, corresponding to the static contact angle ranging from 0 to 180, can be controllably simulated. For wetting fluids, the spontaneous capillary imbibition (SCI) is evident in MDPD simulations. It is found that, whereas the corrected Lucas-Washburn equation (taking into account the dynamic contact angle and the fluid inertia) can well describe the SCI simulation result for the completely wetting fluid, it deviates, to a notable degree, from the results of partly wetting fluids. In particular, this corrected equation cannot be used to describe the spontaneous capillary drainage (SCD) processes. To solve this problem, we derive an improved form of the Lucas-Washburn equation, in which the slip effects of fluid particles at the capillary wall are treated. Such an improved equation turns out to be capable of describing all the simulation results of both the SCI and the SCD. These findings provide new insights into the SCI and SCD processes and improve the mathematical base.