Simulation numerique directe du transfert de matiere autour d'unegoutte dans un liquide immiscible

International audienceÀ partir du diagramme empirique de Clift et des propriétés physico-chimiques du système d'extraction considéré dans l'étude, la forme de la goutte est supposée sphérique dans un premier temps. A partir de simulations numériques directes, l'effet de paramètres physiques clés (tels que le rapport de viscosité entre la goutte et la phase continue, le rapport de densité, le coefficient de distribution du soluté, etc.) et de la nature de l’écoulement sur la physique du problème est étudié et analysé

Influence de certains paramètres physiques sur le transfert de matière entre une goutte et un liquide immiscible

Responsable CEA : Sophie ChartonDirecteur universitaire : Eric ClimentNational audienc

Simulation numérique directe du transfert de matière autour d'une goutte dans un liquide immiscible

International audienc

Hydrodynamics and Conjugate Mass Transfer from a Translating Spherical Droplet in a Continuous Phase

International audienceThe improvement and optimization of separation processes, such as liquid-liquid extraction, are based most importantly on a good understanding and modeling of the hydrodynamic coupling between the two phases and the mass transfer across the interface. This is becoming a challenge for complex polydispersed systems while population of droplets or bubbles is often considered in these processes. Given the complexity of an accurate description of such systems, the investigation of mass transfer at the microscale of a single droplet moving in the surrounding immiscible phase is of prime importance. This study represents a step towards the derivation of general and reliable mass transfer resistance correlations. Many key physical parameters (such as the viscosity ratio, diffusivity ratio, flow configuration, etc.) may impact directly both the hydrodynamics of a moving droplet in a continuous phase and the (corresponding?) extraction efficiency. Under the hydrodynamic conditions corresponding to solvent extraction processes, the droplets usually achieve a spherical shape. Hence, a fixed (i.e. non deformable) mesh is considered in this study. A numerical investigation has been carried out by DNS to investigate the coupling between the internal and the external flows and their respective effects on the mass transfer rate. JADIM, the CFD code developed at IMFT, was used and adapted in this aim. The finite volume scheme implemented, together with the use of an orthogonal curvilinear mesh, was shown to enable good description of interfacial phenomena. The temporal evolution and the spatial concentration distribution have been studied, analyzed and then validated on reference test cases. A specific jump condition has been implemented in order to accurately represent the convection/diffusion and mass transfer coupling at the interface between the droplet and the surrounding liquid. Original simulations have been made to investigate the interaction between the internal and the external flows related to the motion of a single droplet, and the evolution of the Sherwood number through the influence of the dimensionless numbers that control the physical system

Hydrodynamics and mass transfer from a spherical droplet moving through a continuous phase

International audienc

Hydrodynamics and Conjugate Mass Transfer from aTranslating Spherical Droplet in a Continuous Phase

International audienceThe optimization of separation processes, like liquid-liquid extraction, and improvement ofseparation apparatus design start most importantly with a good understanding of thehydrodynamic coupling between the two phases and the mass transfer across the interface. Thistask becomes challenging for complex polydisperse systems. Population of droplets or bubblesis often considered in these processes. Given the complexity of a global study of the system, thestudy of mass transfer at the scale of a single droplet moving in the surrounding immisciblephase is of prime importance. This study represents a major step towards derivation of reliablemass transfer resistance correlations