Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Poster: Wetting, Micro and nanofluidics

CPP 21.6: Poster

Mittwoch, 28. März 2012, 11:00–13:00, Poster A

Simulation of droplet traffic in asymmetric microfluidic loop — •Erfan Kadivar, Stephan Herminghaus, and Martin Brinkmann — Max Planck Institute for Dynamics and Self-Organization, Fassberg 17, D-37077, Göttingen, Germany

As observed in the recent experiments, the repartition of droplets at the inlet of an asymmetric microfluidic loop depends on the droplet size and distance of consecutive droplets [1-2]. In this work we present a numerical study of the droplet traffic at microfluidic channel with an asymmetric loop. As we assume the flat channel, we consider the flow in the Hele-Shaw limit, where the dynamics of two phases can be described by an effectively two dimensional Darcy flow. The continuity equation in combination with Darcy's law provides a self-consistent integral representation of the pressure on the boundary of the droplets and the side walls of the channels which is solved using standard boundary element methods. In addition to the Laplace pressure, we consider a disjoining pressure acting on the interface touching the interface of another droplet or the side wall. Finally we calculate the fraction of droplets flowing through in each arm of the loop as function of droplet size, arm length ratio, and distance between two consecutive droplets.

[1] M. Belloul, and et al, Soft Matter 7, 9453 (2011).

[2] W. Choi, and et al, Lip on a Chip 11, 3970 (2011).