title: Thermal gravitational separation of ternary mixture n-dodecane/isobutylbenzene/tetralin components in a porous medium.
abstract: Our present work focuses on the coupling between thermal diffusion and convection in order to improve the thermal gravitational separation of mixture components. The separation phenomenon was studied in a porous medium contained in vertical columns. We performed analytical and numerical simulations to corroborate the experimental measurements of the thermal diffusion coefficients of ternary mixture n-dodecane, isobutylbenzene, and tetralin obtained in microgravity in the international space station. Our approach corroborates the existing data published in the literature. The authors show that it is possible to quantify and to optimize the species separation for ternary mixtures. The authors checked, for ternary mixtures, the validity of the "forgotten effect hypothesis" established for binary mixtures by Furry, Jones, and Onsager. Two complete and different analytical resolution methods were used in order to describe the separation in terms of Lewis numbers, the separation ratios, the cross-diffusion coefficients, and the Rayleigh number. The analytical model is based on the parallel flow approximation. In order to validate this model, a numerical simulation was performed using the finite element method. From our new approach to vertical separation columns, new relations for mass fraction gradients and the optimal Rayleigh number for each component of the ternary mixture were obtained.
authors.affiliation: Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex, France.
authors.forename: Mohamed Aziz
authors.initials: MA
authors.lastname: Larabi
authors.affiliation: Laboratoire de Mécanique des Fluides et d'Acoustique, 36 Avenue Guy de Collongue, 69130 Écully, France.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Mutschler
authors.affiliation: Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex, France.
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Mojtabi