水在纳米管道中流动行为的分子动力学模拟

采用分子动力学方法模拟了纳米管道内水分子的流动行为. 考察了压强差、 管道直径和管道长度对通量的影响, 验证了流体在直径为2～2.8 nm管道中的流动行为符合Hagen-Poiseuille(HP)方程. 研究发现, 末端效应具有长度依赖性, 对于较短的管道其末端效应更为显著. 为了深入了解真实非均匀管道的流动行为, 使用直径不同的2种管道以不同的连接顺序组合成4种非均匀管道模型, 最终得到了不同的流量. 提出了二元管道模型, 对非均匀管道内的流动行为进行了初步探讨.

Molecular Dynamics Simulation of the Flow Behavior of Water Through Nanopipes

Molecular dynamics was adopted to simulate the flow behavior of water through nanopores at atomistic level. Effects of the pressure difference, the diameter and the length of nanopipes to the flux of fluid were validated according to Hagen-Poiseuille(HP) equation with diameter of the nanopipe between 2 nm and 2.8 nm. Further investigation found that thereis the end effect to the flow behavior of fluid and the end effect depends on the nanopipe length and more significant for shorter nanopipes. In order to understand the flow behavior of real nanopores, we proposed four different nanopipe models possessing variational diameters along the pipe, which consists of two different diameter pipes and finally result in different fluxes. The behavior of fluid through the diameter variational nanopipes was elementarily discussed with a binary pipe model, which was put forward in the present study.