AXIAL TRANSPORT OF LOW DENSITY, SIMPLE FLUID IN NANOCHANNEL SYSTEMS WITH PARTIAL MOLECULAR WALL SLIP: MODELING AND SIMULATION

Abstract

A model for gas transport through nanochannels is presented. Molecular simulations of Argon (modeled as a Lennard–Jones fluid) flowing over a carbon surface were performed to develop a correlation for molecular wall slip based on temperature and angle of collision. The correlation is used to modify the oscillatory model of diffusion. Molecular transport is argued to be in one of two domains: near wall localized diffusion at low and moderate temperatures, and delocalized diffusion at high temperatures. The molecular diffusivity is found to exceed that predicted by Knudsen diffusion at high temperatures, and diffusive oscillatory models at all temperatures. Molecular simulations compare favorably with the presented model.