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Transport of simple fluids in nanopores: Theory and simulation
Author(s) -
Bhatia Suresh K.,
Nicholson David
Publication year - 2006
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.10580
Subject(s) - viscosity , specular reflection , nanopore , reflection coefficient , chemistry , density functional theory , mechanics , kinetic theory , reflection (computer programming) , transport phenomena , flow (mathematics) , chemical physics , classical mechanics , materials science , thermodynamics , physics , nanotechnology , computational chemistry , optics , computer science , programming language
A theory is discussed of single‐component transport in nanopores, recently developed by Bhatia and coworkers. The theory considers the oscillatory motion of molecules between diffuse wall collisions, arising from the fluid–wall interaction, along with superimposed viscous flow due to fluid–fluid interaction. The theory is tested against molecular dynamics simulations for hydrogen, methane, and carbon tetrafluoride flow in cylindrical nanopores in silica. Although exact at low densities, the theory performs well even at high densities, with the density dependency of the transport coefficient arising from viscous effects. Such viscous effects are reduced at high densities because of the large increase in viscosity, which explains the maximum in the transport coefficient with increase in density. Further, it is seen that in narrow pore sizes of less than two molecular diameters, where a complete monolayer cannot form on the surface, the mutual interference of molecules on opposite sides of the cross section can reduce the transport coefficient, and lead to a maximum in the transport coefficient with increasing density. The theory is also tested for the case of partially diffuse reflection and shows the viscous contribution to be negligible when the reflection is nearly specular. © 2005 American Institute of Chemical Engineers AIChE J, 2006