Pulsed Flow Mixing for Biomems Applications

Many microfluidic applications require the mixing of reagents, but efficient mixing in these laminar (i.e., low Reynolds number) systems is typically difficult. Instead of using external fields, miniature stirrers, complex geometries, and/or relatively long channels, we demonstrate the merits of flow rate time dependency mixing in a simple “--II-” channel confluence. By means of computational fluid dynamics (CFD) as well as by physically mixing two aqueous reagents, we show good mixing right at the confluence. We also reveal the benefits of pulsing the reagents such that they pass multiple times through spatial features, which leads to mixing over shorter distances.