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Effective diffusion coefficients in square arrays of filament bundles
Author(s) -
Transvalidou Faye,
Sotirchos Stratis V.
Publication year - 1996
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.690420904
Subject(s) - knudsen number , knudsen diffusion , mean squared displacement , diffusion , bundle , thermal diffusivity , radius , protein filament , porous medium , square (algebra) , porosity , brownian motion , confined space , materials science , mechanics , mass diffusivity , thermodynamics , chemistry , geometry , physics , mathematics , composite material , molecular dynamics , computational chemistry , computer security , organic chemistry , quantum mechanics , computer science
Abstract The effects of the polydispersity of the characteristic diffusion length of the pore space of fibrous media on the effective diffusion coefficients of gases are studied by investigating the problem of gaseous diffusion in the Knudsen, transition, and bulk regimes in square arrays of filament bundles, of cylindrical cross section, consisting of unidirectional, freely overlapping cylindrical filaments. Effective diffusion coefficients are computed using a stochastic simulation method based on the computation of the mean square displacement of a large number of molecules (random walkers) diffusing in the pore space. The dependence of effective diffusivity on filament to bundle radius ratio, intrabundle porosity, interbundle porosity, and Knudsen number is investigated in detail. The computed diffusivities are compared to the predictions of analytical or semianalytical formulas based on expressions derived in the literature for two‐phase media or bidisperse pore structures.