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Morphological properties of flocs under turbulent break‐up and restructuring processes
Author(s) -
Vlieghe M.,
Frances C.,
CoufortSaudejaud C.,
Liné A.
Publication year - 2017
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.15745
Subject(s) - flocculation , breakage , microscale chemistry , breakup , turbulence , radius of gyration , thixotropy , mechanics , shear (geology) , gyration , materials science , biological system , statistical physics , physics , chemical engineering , engineering , mathematics , polymer , composite material , mechanical engineering , biology , mathematics education
Bentonite flocculation was performed in a Taylor–Couette reactor coupled with an in situ method of image acquisition and analysis. A hydrodynamic sequencing is imposed to perform successive cycles of flocculation and breakage. Depending on the shear rate applied during the breakage step, one or two cycles are needed after the first flocculation step to recover a full reversibility on both size and shape factors. The breakup step produces flocculi that are the building blocks for the next. The re‐flocculation steps produce smaller sizes and more regular shapes than the initial growth step. The floc size is calibrated by the turbulence as the radius of gyration is close to the Kolmogorov microscale whereas the floc structure is determined by flocculi aggregates. An analysis of the change of the flocs morphology, despite of their diversity, can also be achieved thanks to some relevant moments of the distributions. © 2017 American Institute of Chemical Engineers AIChE J , 63: 3706–3716, 2017