Marangoni-driven convection around exothermic autocatalytic chemical fronts in free-surface solution layers - Archive ouverte HAL
Article Dans Une Revue Chaos: An Interdisciplinary Journal of Nonlinear Science Année : 2012

Marangoni-driven convection around exothermic autocatalytic chemical fronts in free-surface solution layers

Résumé

Gradients of concentration and temperature across exothermic chemical fronts propagating in free-surface solution layers can initiate Marangoni-driven convection. We investigate here the dynamics arising from such a coupling between exothermic autocatalytic reactions, diffusion, and Marangoni-driven flows. To this end, we numerically integrate the incompressible Navier-Stokes equations coupled through the tangential stress balance to evolution equations for the concentration of the autocatalytic product and for the temperature. A solutal and a thermal Marangoni numbers measure the coupling between reaction-diffusion processes and surface-driven convection. In the case of an isothermal system, the asymptotic dynamics is characterized by a steady fluid vortex traveling at a constant speed with the front, deforming and accelerating it [L. Rongy and A. De Wit, J. Chem. Phys. 124, 164705 (2006)]. We analyze here the influence of the reaction exothermicity on the dynamics of the system in both cases of cooperative and competitive solutal and thermal effects. We show that exothermic fronts can exhibit new unsteady spatio-temporal dynamics when the solutal and thermal effects are antagonistic. The influence of the solutal and thermal Marangoni numbers, of the Lewis number (ratio of thermal diffusivity over molecular diffusivity), and of the height of the liquid layer on the spatio-temporal front evolution are investigated.
Fichier principal
Vignette du fichier
rongy_19853.pdf (1.08 Mo) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01784333 , version 1 (03-05-2018)

Identifiants

Citer

Laurence Rongy, Pauline Assemat, Anne de Wit. Marangoni-driven convection around exothermic autocatalytic chemical fronts in free-surface solution layers. Chaos: An Interdisciplinary Journal of Nonlinear Science, 2012, vol. 22 (n° 3), pp. 03710/16-03710/10. ⟨10.1063/1.4747711⟩. ⟨hal-01784333⟩
40 Consultations
52 Téléchargements

Altmetric

Partager

More