Computer simulations of colloidal particles under flow in microfluidic channels

Abstract

We study the propagation of single, neutrally buoyant rigid spheres under pressure-driven flow by means of extensive computer simulations that correctly account for hydrodynamic interactions. We first consider a system geometry consisting of two parallel plane walls and achieve very good agreement with experimental results [M. E. Staben and R. H. Davis, Int. J. Multiphase Flow, 2005, 31, 529]. In the second part of our analysis, we simulate the flow of tracer particles through a hexagonal array of cylindrical obstacles, whose axis lies parallel to the gradient–vorticity plane of the flow. We find that the presence of the obstacles causes a significant slowdown of the tracer particles and that their velocities respond in a highly non-linear way to an increasing pressure drop.