Numerical simulation of droplet formation in a microchannel device

Abstract

The formation of droplets is a phenomenon of particular importance in the development of industrial emulsions. The quality of these compounds is associated with droplet size and stability over time. Anna et al.(2003) developed a methodology named "flow focusing" to improve droplet formation processes for engineering applications. In this work, Computational Fluid Dynamics (CFD) based techniques are used to assess the capacity of a pseudo-2D numerical model to reproduce the formation of water droplets within silicon oil, as obtained during experiments. Average time of droplet onset obtained via numerical analysis was 1.5 times larger than observed experimentally, whereas droplets convection velocity and diameter predictions differed by 40-45% and 60%, respectively. Nevertheless, the calculated velocity profiles downstream of the discharge slot reproduced the expected free-jet shear layer according to outer/inner flow ratio.