Describing surface tension and wetting behavior of emulsion droplets using the deformable particle model*

The behavior of fluids in contact with the boundaries of microfluidic devices is primarily determined by the surface tensions at the triple line, where the solid, liquid, and gas phases connect. In this work, we implement surface tension into the deformable particle model (DPM) and compare the equilibrium shape of the particle with experiments. We also carry out discrete element method (DEM) simulations of shape-changing particles flowing through narrow channels under the influence of gravity and compare the results for the DPM simulations to those from experiments on quasi-2D flows of oil droplets in water through constrictions. We measure the droplet shape and velocity as a function of time during the flows and compare the droplet trajectories as a function of the surface tension.