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Pattern formation in fluidized beds as a tool for model validation: A two-fluid model based study

Wu, K; de Martín, L; Mazzei, L; Coppens, MO; (2016) Pattern formation in fluidized beds as a tool for model validation: A two-fluid model based study. Powder Technology , 295 pp. 35-42. 10.1016/j.powtec.2016.03.011. Green open access

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Abstract

Computational fluid dynamics (CFD) models have been broadly used during the last twenty years to engineer and understand fluidized beds. Nevertheless, there is some controversy about the rigor of their current validation methodologies (Powder Technol. 139 (2004), 99). A robust tool to determine whether or not a model reproduces-let alone, can predict-the dynamics of a fluidized bed is still missing. This is especially relevant for the validation of the fluid-particle closures that are emerging with the help of direct numerical simulation.More than a decade ago, it was demonstrated experimentally that regular patterns emerge in pulsed fluidized beds under certain experimental conditions. These patterns are not a singular feature of the dynamics, such as average bubble size or bed expansion, but form as a result of a precise coupling between multi-scale physical phenomena. Remarkably, CFD has not been able, so far, to reproduce the experimental bubble patterns convincingly.In this work, we want to bring to the attention of the fluidization community the power of pattern formation in fluidized beds as a tool for model validation. As a proof of concept, we apply this validation test to two-fluid models. Our two-fluid simulations reproduce bubble properties reasonably well, but fail to reproduce the experimentally witnessed patterns, suggesting that the physics of the fluidized state are not correctly captured by this approach, under any of its common implementations.

Type: Article
Title: Pattern formation in fluidized beds as a tool for model validation: A two-fluid model based study
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.powtec.2016.03.011
Publisher version: http://dx.doi.org/10.1016/j.powtec.2016.03.011
Language: English
Additional information: Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Keywords: Fluidization; Structuring; CFD; Validation; Eulerian–Eulerian; Pulsation
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/1477364
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