Fluidized-bed measurements of carefully-characterized, mildly-cohesive (Group A) particles

Fluidization is sensitive to mild cohesion levels, as evidenced by the different flow behaviors of Geldart Group A and Group B particles. Additionally, cohesion is extremely sensitive to surface roughness. Here, mildly cohesive (Group A) spherical particles were carefully characterized and used in high-fidelity experiments of defluidization, bed expansion, and bubble characterization. The experiments were conducted such that van der Waals forces were the only source of cohesion, and thus the results presented can be used for validating Discrete Element Method (DEM) and/or continuum models. Particle characterization includes surface roughness and adhesion (pull-off) force, which can be used for modeling the van der Waals force. Additionally, the particle friction coefficient, coefficient of restitution, shape (sphericity), and diameter were measured via a suite of simple experiments. This level of particle characterization, which is critical for the validation of cohesive models (DEM and continuum), has not been reported in previous fluidization studies. Accordingly, the characterization experiments employed here are described in sufficient detail for straightforward adaption elsewhere. (C) 2016 Elsevier B.V. All rights reserved.