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A functional subgrid drift velocity model for filtered drag prediction in dense fluidized bed
Author(s) -
Parmentier JeanFrançois,
Simonin Olivier,
Delsart Olivier
Publication year - 2012
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.12647
Subject(s) - drag , mechanics , polygon mesh , superficial velocity , fluidized bed , flow (mathematics) , drift velocity , fluidization , filter (signal processing) , two fluid model , flow velocity , particle (ecology) , statistical physics , physics , mathematics , geology , geometry , thermodynamics , computer science , oceanography , quantum mechanics , computer vision , electron
Abstract Due to computational time limitations, fully resolved simulations using the two‐fluid model of the flow inside industrial‐scale fluidized beds are unaffordable. The filtered approach is used to account for the effect of small unresolved scales on the large resolved scales computed with “coarse” realistic meshes. Using a fully resolved simulation, we highlight the need to account for a subgrid drift velocity to obtain the correct bed expansion when using coarse meshes. This velocity, defined as the difference between the filtered gas velocity seen by the particle phase and the resolved filtered gas velocity, modify the effective relative velocity appearing in the drag law. We close it as a correction of the resolved relative velocity depending on the filtered particle concentration and the filter size. A dynamic procedure is used to adjust a tuning parameter. Bed expansion obtained with a posteriori test on coarse‐grid simulations matches well to fully resolved simulations. © 2011 American Institute of Chemical Engineers AIChE J, 2012