The settling of fine cohesive powders
Departamento de Electrónica y Electromagnetismo, Facultad de
Física Avda. Reina Mercedes s/n, 41012 Sevilla, Spain
2 Laboratoire de Physique des Matériaux Divisés et des Interfaces Université de Marne-la-Vallée, Bâtiment Lavoisier 5 Bvd. Descartes, F-77454 Marne-la-Vallée Cedex 2, France
Accepted: 19 February 2001
We investigate the settling of an initially fluidized bed of a fine cohesive powder. Experimental results on the sedimentation rate cannot be fitted by theoretical and empirical equations existing in the literature and derived for non-cohesive spheres. We extend these equations to account for the adhesion-induced aggregation of fine particles. The number of particles per aggregate N and the ratio of aggregate radius R to particle radius, a, have been chosen as fitting parameters. Results from two independent approaches are in very good agreement with the experimental data for approximately the same values of N and R. Pictures taken from the fluidized bed show that the average aggregate radius matches the predicted one.
PACS: 47.55.Kf – Multiphase and particle-laden flows / 47.55.Mh – Flows through porous media / 61.43.Gt – Powders, porous materials
© EDP Sciences, 2001