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On the fluidization/sedimentation velocity of a homogeneous suspension in a low-inertia fluid

Amin, Ahmad and Girolami, Laurence and Risso, Frédéric On the fluidization/sedimentation velocity of a homogeneous suspension in a low-inertia fluid. (2021) Powder Technology, 391. 1-10. ISSN 0032-5910

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Official URL: https://doi.org/10.1016/j.powtec.2021.05.073


The modeling of the fluidization or sedimentation velocity of a suspension of solid particles is revisited by examining experiments conducted in either a liquid or a gas. A general expression is found in the case of negligible fluid inertia, i.e. at low Reynolds or Archimedes number. It is built as the product of the velocity of an isolated particle by three non-dimensional corrections that each takes into account a specific physical mechanism. The first correction reflects the variation of the buoyancy with the particle concentration. The second correction describes how the drag force increases with the concentration in case of negligible particle inertia. The third one accounts for the further increase of the drag when the particle inertia is increased. Remarkably, each correction only relies on a single of the three independent non-dimensional groups that control the problem: (1) the particle volume fraction Φs ; (2) the ratio Φs /Φ pack where Φ pack is the bed packing concentration; (3) the Stokes number St 0 , which characterizes the inertia of the particles and controls their agitation. Moreover, the onset of the instability that separates the homogeneous regime from the heterogeneous one is found to be controlled similarly by the Stokes number. Empirical expressions of the corrections are given, which provide a reliable tool to predict fluidization and sedimentation velocities for all values of the three non-dimensional numbers. The present results emphasize the crucial role of particle inertia, which is often disregarded in previous modeling approaches, such as that of Richardson and Zaki.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Université de Tours (FRANCE)
Laboratory name:
Region Centre-Val de Loire (FRANCE)
Deposited On:11 Jun 2021 10:53

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