Soret-driven convection and separation of binary mixtures in a porous horizontal slot submitted to a heat flux

Marie-Catherine Charrier-Mojtabi (1) , Bilal Elhajjar (2) , Bafétigué Ouattara (2) , Abdelkader Mojtabi (2) , Pierre Costeseque (2)

1 PHASE - Laboratoire Physique de l'Homme Appliquée à Son Environnement
2 IMFT - Institut de mécanique des fluides de Toulouse

The onset of Soret-driven convection in a shallow porous horizontal layer filled with a binary mixture and submitted to a vertical heat flux on the two horizontal walls is investigated. We study the species separation between the two vertical ends of the cell, which appears for low values of the Rayleigh number and for positive separation ratio. An analytical solution is performed and the separation is expressed in terms of thermal Rayleigh number, Lewis number, separation ratio and aspect ratio of the cell. These analytical results are corroborated by direct non-linear numerical simulations. Then, the results are compared with those obtained in a differentially heated vertical cavity.

Mots clés: Convection; Thermodiffusion; Thermogravitation; Soret effect; Species separation

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Marie-Catherine Charrier-Mojtabi, Bilal Elhajjar, Bafétigué Ouattara, Abdelkader Mojtabi, Pierre Costeseque. Soret-driven convection and separation of binary mixtures in a porous horizontal slot submitted to a heat flux. Comptes Rendus Mécanique, 2011, vol. 339, pp. 303-309. ⟨10.1016/j.crme.2011.03.006⟩. ⟨hal-00926373⟩