Séminaire de Benoit SHEID

Séminaire de Benoit Sheid (ULB, Bruxelles) sur le thème  « Raydrop: a universal single/double emulsion generator based on a non-embedded co-flow-focusing ».

Le mercredi 30 Novembre 2022 à 9h30 en salle Sauternes.

We present a non-embedded co-flow-focusing device for single and double-emulsification in microfluidics. Experimental results demonstrate the universality of the device in terms of the variety of fluids that can be emulsified, as well as the range of droplet radii that can be obtained, without neither the need of surfactant nor coating. In a first part, A quasi-static model is developed and shows excellent predictive capability for the size of the droplets. Our results also demonstrate that the mechanism for the dripping-to-jetting transition in this quasi-static limit is intrinsically nonlinear and differs from the absolute-to-convective transition of the Rayleigh-Plateau instability for a jet. In a second part, we investigate mass transfer around bubbles and drops flowing in a cylindrical microchannel. We show different concentration patterns and the dependence of the Sherwood numbers for five different regimes in terms of the Péclet number. We finally show some practical examples of micro-encapsulation.