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Pré-publication, Document de travail

The transition to aeration in two-phase mixing in stirred vessels

Abstract : We consider the mixing of a viscous fluid by the rotation of a pitched blade turbine inside an open, cylindrical tank, with air as the lighter fluid above. To examine the flow and interfacial dynamics, we utilise a highly-parallelised implementation of a hybrid front-tracking/level-set method that employs a domain-decomposition parallelisation strategy. Our numerical technique is designed to capture faithfully complex interfacial deformation, and changes of topology, including interface rupture and dispersed phase coalescence. As shown via transient, three-dimensional direct numerical simulations, the impeller induces the formation of primary vortices that arise in many idealised rotating flows as well as several secondary vortical structures resembling Kelvin-Helmholtz, vortex breakdown, blade tip vortices, and end-wall corner vortices. As the rotation rate increases, a transition to 'aeration' is observed when the interface reaches the rotating blades leading to the entrainment of air bubbles into the viscous fluid and the creation of a bubbly, rotating, free surface flow. The mechanisms underlying the aeration transition are probed as are the routes leading to it, which are shown to exhibit a strong dependence on flow history.
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Pré-publication, Document de travail
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https://hal.archives-ouvertes.fr/hal-02994847
Contributeur : Damir Juric <>
Soumis le : dimanche 8 novembre 2020 - 14:33:06
Dernière modification le : lundi 22 février 2021 - 16:21:15
Archivage à long terme le : : mardi 9 février 2021 - 18:34:04

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Aeration.pdf
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  • HAL Id : hal-02994847, version 1

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Lyes Kahouadji, Assen Batchvarov, Cristian R. Constante Amores, Seungwon Shin, Jalel Chergui, et al.. The transition to aeration in two-phase mixing in stirred vessels. 2020. ⟨hal-02994847⟩

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