纳米尺度边界滑移的分子动力学模拟研究

Study of Nanoscale Boundary Slip Behavior of a Confined Liquid by Molecular Dynamic Simulation

利用分子动力学模拟方法研究了纳米尺度超薄膜润滑的边界滑移现象,分别模拟考察了固液作用势、固液密度差异和温度对滑移长度的影响.结果表明:在固液作用势较强的情况下,滑移长度随着温度的增加而增大;当固液作用势较弱时,滑移长度随着温度的增加反而下降;滑移界面上、下的层状有序化差异程度是导致滑移的主要原因;应用所建立的方法可以较好地解释不同物理参数条件下的壁面滑移问题.

The slip behavior between a confined liquid and solid walls subject to planar shearing was investigated using molecular dynamic simulation. Thus a wide range of fluid-solid interaction strength, fluid density, and fluid temperature were simulated in order to find the dominant effects on the slip length between the fluid and the solid wall, which is a key parameter for fluid dynamics. Results indicated that the slip length increased with increasing temperature under a large solid-liquid potential, while it decreased with increasing temperature under a small solid-liquid potential. It was supposed that the structure difference between the neighboring layers of the slippage interface was responsible for the slip behavior.