Étude expérimentale de l’intensification des transferts dans un échangeur réacteur statique : mélange de deux fluides non-miscibles

摘要

This work concerns the characterization emulsification phenomenon of two immiscible phases in a static mixer-reactor HEV (High Efficiency Vortex) in a turbulent flow. This new type of mixer generates coherent structures in the form of longitudinal counter-rotative vortices. The resulting flow enhances radial mass transfer and thus facilitates the dispersion of two immiscible phases (water/oil). Emulsions obtained in this way are stabilized by encapsulation of oil droplets. Statistics of encapsulated emulsions are then analysed by using optic microscopy and the efficiency of the system is studied by mean-Sauter diameter and granulometric distribution. Energy efficiency of this mixer is compared with other mixers for a given interface area, energy cost of HEV is 1000 times smaller.In the single phase flow regime two measurement campaigns by LDV and PIV have been carried out. The aim here is to study the turbulence structure of the flow generated by the mixer and particularly the more energetic structures present in the base flow. It provides a basic background for the comprehension and explanation of the physical mechanisms which occur in the fractioning of the droplets and therefore the efficiency of the mixer.Parallel work has been carried out on the flow in a twisted pipe with alternating curvature-plane, susceptible to the generation of chaotic fluid-particle trajectories. This flow regime is commonly referred to as "chaotic advection". The aim of this work was to develop a simplified mathematical model for estimation of Nusselt number in chaotic as well as helicoidally coiled heat exchanger which avoids heavy computations required by the resolution of the Navier-Stokes and energy equations.