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Use of trajectory analysis to study stability of colloidal dispersions in flow fields
Author(s) -
Zeichner G. R.,
Schowalter W. R.
Publication year - 1977
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.690230306
Subject(s) - laminar flow , shearing (physics) , flocculation , extensional definition , mechanics , colloid , coagulation , brownian motion , materials science , classical mechanics , physics , thermodynamics , chemical engineering , engineering , geology , psychology , paleontology , tectonics , quantum mechanics , psychiatry
Trajectories have been computed for two equal sized spherical particles in simple laminar shearing and in uniaxial extensional flows. Effects of interparticle attraction, electrostatic repulsion, and hydrodynamics were included. The results are pertinent to questions of colloidal stability under various conditions of flow. Particulate dispersions can react in several different ways as the intensity of shearing is increased from zero: the dispersion can remain stable; it can be redispersed, if it had been initially flocculated into a weak secondary minimum in the interparticle potential curve; it can be flocculated into a strong primary minimum in the potential curve; or, in extreme cases, it can be redispersed from the primary minimum. Results are presented which illustrate criteria for flocculation or stability to both laminar shearing and extensional flow. It is shown that hydrodynamic effects can significantly alter the criteria developed for stability of dispersions to Brownian coagulation.