Comparative CFD-DEM study of flow regimes in spout-fluid beds--颗粒学报PARTICUOLOGY

Hoorijani, H., Esgandari, B., Zarghami, R., Sotudeh-Gharebagh, R., & Mostoufi, N. (2024). Comparative CFD-DEM study of flow regimes in spout-fluid beds. Particuology, 85, 323-334. https://doi.org/10.1016/j.partic.2023.07.011

Comparative CFD-DEM study of flow regimes in spout-fluid beds

Hamed Hoorijani ^a, Behrad Esgandari ^b, Reza Zarghami ^a, Rahmat Sotudeh-Gharebagh ^a, Navid Mostoufi ^a *

a Multiphase Systems Research Lab, School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran
b Department of Particulate Flow Modelling, Johannes Kepler University, Altenbergerstr. 69, 4040, Linz, Austria

10.1016/j.partic.2023.07.011

Volume 85, February 2024, Pages 323-334

Received 11 June 2023, Revised 5 July 2023, Accepted 12 July 2023, Available online 27 July 2023, Version of Record 3 August 2023.

E-mail: mostoufi@ut.ac.ir

Highlights

• Hydrodynamics of a spout fluidized bed in three flow regimes is studied by CFD-DEM.

• The mixing quality of various flow regimes are compared via Lacey mixing index.

• Particle dynamics are determined by dispersion coefficient and axial displacement.

• Granular temperature is used to describe particle dynamics in flows.

Abstract

Spout-fluid beds are unique systems that require thorough study prior to their industrial application. In this study, the hydrodynamics of spout-fluid beds were investigated using 3D computational fluid dynamics coupled with discrete element method (CFD-DEM). Three flow regimes, including jet-in-fluidized bed, spouting-with-aeration, and intermediate/spout-fluidization were studied, and the particle mixing was quantified in these regimes using the Lacey mixing index. The results showed that both axial and lateral mixing rates are better in jet-in-fluidized bed and the spouting-with-aeration flow regimes, with the axial mixing being superior to the lateral in all flow regimes. Examining the diffusivity coefficient revealed that mixing in the jet-in-fluidized bed flow regime is better due to the formation and eruption of bubbles in the annulus. Additionally, the granular temperature was analyzed in all flow regimes, and higher particle velocity fluctuations were observed in the spouting-with-aeration and the jet-in-fluidized bed flow regimes due to the higher spout gas velocity and formation of bubbles in the annulus. This study provides valuable insights into the hydrodynamics of spout-fluid beds in different flow regimes, which can aid in the design and optimization of spout-fluid bed reactors for various industrial applications.

Graphical abstract

Keywords

Flow regime; Mixing; Diffusivity; CFD-DEM; Hydrodynamics; Spout-fluid bed

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