On the experimental investigation and numerical fluid dynamic simulation of L-L water-in-oil dispersions in Y-junctions under the presence of dissolved CO2

Abstract The use of micro-devices in supercritical fluid extraction processes has been widely studied. However, few or none investigations aiming to understand emulsification processes involving supercritical carbon dioxide (scCO 2 ) have been carried out yet. Thus, this work intends to provide knowledge of the breakup of Liquid-Liquid (L-L) water-in-oil (W/O) microfluidic processes under the presence of dissolved CO 2 . To that end, a Y-junction made of PMMA (polymethyl-methacrylate) is designed, which enables visual characterisation of dispersions up to pressures of 15 MPa via shadowgraph technique. The dissolution of CO 2 into the continuous oily phase causes a simultaneous reduction in viscosity and interfacial tension, which are important parameters for the formation or stability of emulsions. Nonetheless, the impact that those parameters individually have on the breakup dynamics cannot be known only from experimental data. Computational Fluid Dynamic simulations have been performed to isolate the effect of continuous phase viscosity and interfacial tension in water-in-CO 2 -saturated-oil dispersions.