Two-dimensional numerical simulation of chimney fluidization in a granular medium using a combination of discrete element and lattice Boltzmann methods

Simulation numérique bi-dimensionnelle de la fluidisation en cheminée dans un milieu granulaire par combinaison des méthodes aux éléments discrets et Boltzmann sur réseau

Ngoma, J. ; Philippe, P. ; Bonelli, S. ; Radjaï, F. ; Delenne, J.Y.

Type de document
Article de revue scientifique à comité de lecture
Langue
Anglais
Affiliation de l'auteur
IRSTEA AIX EN PROVENCE UR RECOVER FRA ; IRSTEA AIX EN PROVENCE UR RECOVER FRA ; IRSTEA AIX EN PROVENCE UR RECOVER FRA ; LMGC CNRS UNIVERSITE MONTPELLIER FRA ; UMR IATE INRA CIRAD MONTPELLIER FRA
Année
2018
Résumé / Abstract
We present here a numerical study dedicated to the fluidization of a submerged granular medium induced by a localized fluid injection. To this end, a two-dimensional (2D) model is used, coupling the lattice Boltzmann method (LBM) with the discrete element method (DEM) for a relevant description of fluid-grains interaction. An extensive investigation has been carried out to analyse the respective influences of the different parameters of our configuration, both geometrical (bed height, grain diameter, injection width) and physical (fluid viscosity, buoyancy). Compared to previous experimental works, the same qualitative features are recovered as regards the general phenomenology including transitory phase, stationary states, and hysteretic behaviour. We also present quantitative findings about transient fluidization, for which several dimensionless quantities and scaling laws are proposed, and about the influence of the injection width, from localized to homogeneous fluidization. Finally, the impact of the present 2D geometry is discussed, by comparison to the real three-dimensional (3D) experiments, as well as the crucial role of the prevailing hydrodynamic regime within the expanding cavity, quantified through a cavity Reynolds number, that can presumably explain some substantial differences observed regarding upward expansion process of the fluidized zone when the fluid viscosity is changed.
Source
Physical Review E, vol. 97, num. 05, 23 p.

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