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The calculations of dispersion coefficients inside two‐dimensional randomly packed beds of circular particles
Author(s) -
Jourak Amir,
Frishfelds Vilnis,
Lundström T. Staffan,
Herrmann Inga,
Hedström Annelie
Publication year - 2013
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.13867
Subject(s) - laminar flow , dispersion (optics) , mechanics , voronoi diagram , geometry , computational fluid dynamics , physics , particle (ecology) , vorticity , thermodynamics , materials science , mathematics , vortex , optics , geology , oceanography
The longitudinal ( D L ) and transverse ( D T ) dispersion coefficients in two‐dimensional (2‐D) randomly packed beds of circular particles in a laminar flow regime are derived. A 2‐D discrete system of particles is divided into cells using modified Voronoi diagrams. The relationship between the variation of the stream function and the averaged vorticity is obtained from computational fluid dynamics (CFD) simulations. The whole flow pattern is then obtained by using the principle of energy dissipation rate minimization. The obtained values of D L agree well with 3‐D experimental data for all velocities investigated. At very high velocities, D T in 2‐D appears to be higher than 3‐D experimental data. In addition, the effects of particle‐size distributions, packing structure, and porosity on the D L and D T were studied. One result was that an increase in the width of the particle‐size distribution resulted in higher values of D L and D T at high velocities. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1002–1011, 2013