8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Thu 811:10-14:00P7.53Numerical simulation of the dense droplet packingsflowing in flat microfluidic channelsErfan Kadivar 1 and Martin Brinkmann 11 Max Planck Institute for Dynamics and Self-Organization, Faerg 17, D-37077, Göttingen,GermanyMany microfluidic devices rely on the production and manipulation of large numbers of monodispersedroplets. The control over topological rearrangements in dense droplet packings in particularis important in microfluidic applications of combinatorial chemistry and microbiology. In this workwe present a numerical study of the dynamics of dense droplet packings flowing in flat microfluidicchannels. In the Hele-Shaw limit, the dynamics of the droplets can be described by an effectivelytwo dimensional Darcy flow. The continuity equation in combination with Darcy’s law provides aself-consistent integral representation of the pressure on the boundary of the droplets and the sidewalls of the channels which is solved using standard boundary element methods. In addition to theLaplace pressure, we consider a disjoining pressure acting on the interface touching the interfaceof another droplet or the side wall. This repulsive interaction allows us to quantify the impact ofcontrol parameter such as flow speed and packing fraction on the transitions between various densedroplet packings.53