(412i) Migration and Equilibrium Configuration of Double Emulsion Drops in Microfluidic Channels

Double emulsion drops, or compound drops, such as water in oil in water drops, have significant potential as micro-reactors and drug-delivery agents. In this work we present the dynamic response of compound drops to a Poiseuille Flow in a rectangular channel in a microfluidic environment through direct numerical simulation. We use a finite volume method with front tracking method for interface representation. We show that for the Reynolds numbers of Re = O(1-10) and Capillary number of Ca = O(0.1) and different drop to channel width ratio and different aspect ratio of the channel cross-section, there exist three equilibrium configurations, two with symmetry about the longer side, and one about the shorter side of the channel. Additionally, it is found that the compound drops generally experience more shear force and settle closer to the channel wall compared to simple drops. These findings can aid in designing channels to transport compound drop with known effective shear acting upon it, as well as in devising a sorting mechanism for compound drops based on their geometric properties.