多孔介质中流体输运的孔尺度MD模拟

PORESCALE MD SIMULATION OF FLOW IN POROUS MEDIA

本文采用分子动力学（MD）方法对流体流过单个纳米尺度孔的过程进行数值模拟。纳米尺度孔是由两块平行的三氧化二铝平板构成的。通过对孔内每个水分子施加均匀的外力来驱动流体流动。分子之间的相互作用都采用12—6L—J势能模型来描述。本文数值模拟了流体输运的孔尺度效应，分析了孔尺度对壁面速度是否存在滑移的影响，讨论了驱动力和通道尺度对滑移速度和壁面动力黏性系数的影响，模拟发现存在一临界尺度，它决定了是否存在滑移，还发现特定尺度下存在一临界驱动力，它决定了等效黏度的非牛顿流体特征。

In this paper, the fluid flow inside a nanosized channel style pore formed by two solid parallel walls is studied using molecular dynamics （MD） simulation. Alumina has been chosen as the material of the wall. The flow is initiated by applying a uniform external force on each water molecule inside the channel. 12-6 L-J potentials are chosen in the simulation to describe H20-H20 molecule interactions as well as H20-A1203 molecule interactions. The present work has studied the effect of pore scale on the fluid transport phenomena, analyzed the influence of pore scale on the slip velocity at the wall surface, and discussed the influence of external force and channel scale on slip velocity and viscosity at the wall surface. It has been found that a critical scale exists, which determines whether the slip phenomenon appears, and at certain scale, a critical external force exists, which determines the non-Newtonian fluid characteristics of equivalent viscosity.