Flow of two immiscible liquids with low viscosity in Y shaped microfluidic systems: effect of geometry

This article investigates the formation of albumin droplets in fatty esters by means of a flow focussing geometry where the continuous oil phase is introduced in the two lateral branches of a Y junction. The effect of the geometry is investigated in order to clarify the scales controlling the droplet generation with this type of fluid couple. The transition from regular droplet flow to stratified flow is identified from the experiments. It is found that the droplet size varies linearly with the flow rate ratio between the disperse and continuous phases. This is similar to what is found in T junctions microfluidic systems for low capillary numbers.