Simulation numérique de la convection de Marangoni dans du Li-Br aqueux absorbant

The Marangoni convection effect within absorptive films can be described as the behaviour that brings the boundary between adjoining phases to relapse into a state where the interfacial free energy is minimized as a consequence of the expansion and the contraction of the regions with low and high surface tension. Thus, surface tension gradients lead to a shear stress originating a fluid motion in proximity of the interface and consequently affecting the contingent heat and mass transfer process of absorptive mixtures. However, since the mechanism by which the related transport phenomena can be enhanced has not been clearly understood, neither the upper limit to the benefit provided nor the best surfactant additive is currently known. To provide a direct term of comparison with a nearly two-dimensional apparatus, to clarify the driving force of Marangoni convection and the related transfer performance enhancement within falling film absorbers, this work formulates a numerical model of the fundamental governing equations of vapour absorption in presence of variable surface tension.