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Evaluation of elastic and inelastic contact forces in the flow regimes of Titania nanoparticle agglomerates in a bench-scale conical fluidized bed: A comparative study of CFD-DEM simulation and experimental data

Evaluation of elastic and inelastic contact forces in the flow regimes of Titania nanoparticle agglomerates in a bench-scale conical fluidized bed: A comparative study of CFD-DEM simulation and experimental data

Authors :
Alireza Bahramian
Martin Olazar
Source :
Chemical Engineering Research and Design. 176:34-48
Publication Year :
2021
Publisher :
Elsevier BV, 2021.

Abstract

The present study evaluates elastic and inelastic contact forces in predicting the fluidization characteristics of irregularly shaped Titania nanoparticle agglomerates in a bench-scale conical fluidized bed. At first, experiments were performed to identify the mutual effects of gas velocity and agglomerate size on the instantaneous pressure, bed pressure drop and bed expansion ratio. Rigid complex-agglomerates (∼100−200 μm) were mainly formed in the partially fluidized regime, while soft simple-agglomerates (∼20−70 μm) were primarily formed in the spouting regime. The simulations were performed through the CFD-DEM approach. The error analysis of results in the partially fluidized regime revealed that the combination of Hertz-Mindlin and Johnson-Kendall-Roberts (HM + JKR) model led to a better prediction of the bed pressure drop and bed expansion ratio than the spring-dashpot (LSD) model. In the transition flow regime, the Hysteretic model led to better results of the instantaneous pressure values than those proposed for other flow regimes. In the spouting flow regime, the HM and Thornton models led to over-estimation of bed pressure drop when compared to the LSD model. The comparative results of this study provide promising new insights into the collision mechanism of polydisperse agglomerates in different flow regimes for industrial aspects.

Details

ISSN :
02638762
Volume :
176
Database :
OpenAIRE
Journal :
Chemical Engineering Research and Design
Accession number :
edsair.doi...........2420e7c6fece85caff25243c449df82e
Full Text :
https://doi.org/10.1016/j.cherd.2021.09.027