Particle simulation of
vibrated gas-fluidized beds of cohesive fine powders
Abstract:
We use three-dimensional particle dynamics simulations, coupled with
volume-averaged gas phase hydrodynamics, to study vertically vibrated
gas-fluidized beds of fine, cohesive powders. The volume-averaged
interstitial gas flow is restricted to be one-dimensional (1D). This
simplified model captures the spontaneous development of 1D traveling
waves, which corresponds to bubble formation in real fluidized beds. We
use this model to probe the manner in which vibration and gas flow
combine to influence the dynamics of cohesive particles. We find that as
the gas flow rate increases, cyclic pressure pulsation produced by
vibration becomes more and more significant than direct impact, and in a
fully fluidized bed this pulsation is virtually the only relevant
mechanism. We demonstrate that vibration assists fluidization by
creating large tensile stresses during transient periods, which helps
break up the cohesive assembly into agglomerates.
Available
online from Ind. & Eng. Chem. Res.
(2006); http://arxiv.org/abs/cond-mat/0510115
Manuscript is available in PDF and PS
format.