Breakup of confined drops against a micro-obstacle: an analytical model for the drop size distribution
Résumé
A confined drop flowing against a rectangular obstacle placed off-center in a microfluidic conduct may break into two daughter droplets of different volumes when the capillary number at play C, the ratio between viscous and capillary effects, exceeds a threshold C b. We study the influence of the viscosity ratio p between dispersed and continuous phases on that process by discussing the experimental variations of the volume fraction of the daughter droplets with C and p. A single free-parameter model that yields an analytical formula for the volume of the daughter droplets as a function of the variables at play is introduced. Using this model that well describes our experiments, we accurately determine C b for different p. Our findings underline the key role of confinement on drop breakup showing that C b is three orders of magnitude smaller than the value found in bulk experiments under shear flow and that C b decreases with p in our study.
Domaines
Matière Molle [cond-mat.soft]
Origine : Fichiers produits par l'(les) auteur(s)
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