疏水纳米通道内微流动数值计算方法研究

Molecular Dynamics Research on Micro-Flow in a Hydrophobic Nano-Channel

疏水表面水下减阻研究是当前减阻研究领域的热门课题之一,该类表面一般分布着微纳米尺度的微结构,其附近流动属微流动问题。以疏水纳米通道内微流动为例,探索了将现有微流动相关理论和方法应用于疏水性表面减阻研究的可行性,并结合疏水表面界面特性,给出了疏水纳米通道内微流动的分子动力学数值计算方法(MDS)。其中,在数学模型中,统计系综为正则系综(NVT),势能函数采用Lennard-Jones模型,壁面设定为刚性壁面,壁面疏水性则通过在势能函数中引入修正因子来表征;而在数值计算中,温度校正使用速度标定法,牛顿运动方程求解则采用Verlet算法。实例计算结果表明,疏水微通道内流体密度呈现内高、外低的振荡型对称分布特点,且随着壁面疏水性的增强,振荡程度减弱;同时疏水壁面处存在滑移现象,且滑移量随壁面疏水性增强而增大。

The full paper explains our molecular dynamics research mentioned in the title. Its core consists of： ＂Hydrophobic surfaces drag reduction is one of the hot research topics in the study of the underwater drag reduction currently. There are much of micro-and nano-scale structures on hydrophobic surfaces and the flow is a typical mi- cro-flow. Inquiring into the feasibility of drag reduction studies on hydrophobic surface using the existing micro-flow theory and methods, we choose the micro-flow in hydrophobic nano-channel. Referring to the hydrophobie surface properties, we give a molecular dynamics simulation method, in which NVT is statistical ensemble and Lennard- Jones＇ s potential energy function is used. The hydrophobic wall, which is assumed to be a rigid surface, is charac- terized by the correction factor in the potential energy function. In the calculation, velocity scaling method is used to keep the temperature constant and Verlet method is used to solve the Newton＇s equation. The results show that the density of the fluid surges in the hydrophobic nano-channel. Moreover, significant slip velocity is found near the wall. The simulation results, presented Figs. 8 through 11 and Table 2, are basically consistent with those of the relevant references, so this paper＇s simulation method is logical and valid.＂.