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Effect of drag models on residence time distributions of particles in a wurster fluidized bed: A DEM-CFD study

Liang Li (Institutionen för kemi och kemiteknik, Kemisk apparatteknik) ; J. Remmelgas ; B.G.M. van Wachem ; C. von Corswant ; S. Folestad ; M. Johansson ; Anders Rasmuson (Institutionen för kemi och kemiteknik, Kemisk apparatteknik)
KONA Powder and Particle Journal (0288-4534). Vol. 2016 (2016), 33, p. 264-277.
[Artikel, refereegranskad vetenskaplig]

Fluidized bed coating has been used to coat pellets or tablets with functional substances for a number of purposes. In this coating process, particle wetting, drying and film formation are coupled to particle motion. It is therefore of interest to study particle motion in such fluidized beds and to use the results to develop a model for predicting the quality of the final product. In this paper, we present results from DEM-CFD simulations, i.e. discrete element method and computational fluid dynamics simulations of particle motion in a laboratory-scale Wurster fluidized bed that was also employed in positron emission particle tracking (PEPT) experiments. As the drag force is the dominant interaction between the gas flow and the particle motion in this type of fluidized bed, the effect of drag models on the particle motion is investigated. More specifically, the particle velocity and residence time distributions of particles in different regions calculated from five different drag models are presented. It is found that the Gidaspow and Tang drag models predict both particle cycle and residence times well. The HKL and Beetstra drag models somewhat overestimate the particle velocity in the Wurster tube and therefore predict a reduced number of recirculations and a significantly shorter cycle time.

Nyckelord: CFD , DEM , Drag , Fluidized bed , Particles , Residence time distributions



Denna post skapades 2016-05-11. Senast ändrad 2016-06-03.
CPL Pubid: 236222

 

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Institutioner (Chalmers)

Institutionen för kemi och kemiteknik, Kemisk apparatteknik

Ämnesområden

Fysik

Chalmers infrastruktur