Study on the Characteristics of Gas Molecular Mean Free Path in Nanopores by Molecular Dynamics Simulations

International Journal of Molecular Sciences

Qixin Liu¹ 

[1] School of Civil Engineering and Architecture, Chongqing University of Science and Technology, Chongqing 401331, China

关键词: nanopore;    gas molecular mean free path;    Knudsen number;    molecular dynamics simulation;   

DOI  :  10.3390/ijms150712714

来源: mdpi

【 摘 要 】

This paper presents studies on the characteristics of gas molecular mean free path in nanopores by molecular dynamics simulation. Our study results indicate that the mean free path of all molecules in nanopores depend on both the radius of the nanopore and the gas-solid interaction strength. Besides mean free path of all molecules in the nanopore, this paper highlights the gas molecular mean free path at different positions of the nanopore and the anisotropy of the gas molecular mean free path at nanopores. The molecular mean free path varies with the molecule’s distance from the center of the nanopore. The least value of the mean free path occurs at the wall surface of the nanopore. The present paper found that the gas molecular mean free path is anisotropic when gas is confined in nanopores. The radial gas molecular mean free path is much smaller than the mean free path including all molecular collisions occuring in three directions. Our study results also indicate that when gas is confined in nanopores the gas molecule number density does not affect the gas molecular mean free path in the same way as it does for the gas in unbounded space. These study results may bring new insights into understanding the gas flow’s characteristic at nanoscale.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.