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Entry mass transfer in axial flows through randomly packed fiber bundles
Author(s) -
Bao L.,
Liu B.,
Lipscomb G. G.
Publication year - 1999
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.690451110
Subject(s) - mass transfer , mass transfer coefficient , fiber , mechanics , axial symmetry , constant (computer programming) , boundary layer , fiber bundle , materials science , chemistry , geometry , physics , mathematics , composite material , computer science , programming language
An analysis of the effects of nonuniform fiber packing on external mass‐transfer coefficients for axial flows through bundles of parallel, axially oriented fibers is presented in the entry mass‐transfer limit. In this limit, one can obtain an analytic solution to the mass‐transfer boundary‐layer equations in terms of the velocity gradient on the fiber surface for either a constant wall flux or constant wall concentration. To explicitly calculate mass‐transfer coefficients, a numerical approximation for the velocity gradient is obtained from the conservation of momentum equations using the boundary‐element method. Results indicate that the effective mass‐transfer coefficient depends strongly on fiber packing. Regions of higher fiber packing have lower flows and lower mass‐transfer coefficients than regions of lower packing. The net effect is a dramatic decrease in overall mass‐transfer coefficient relative to mass‐transfer coefficients in regularly packed fiber bundles.