Rapid mixing between ferro-nanofluid and water in a semi-active Y-type micromixer

This study investigates the mixing phenomena between ferro-nanofluid (a water solution with suspended Fe3O4 nanoparticles)and water in a Y-type semi-active micromixer. A permanent magnet with a magnetic strength of 2200 G was installed directly under the mixer at a location behind the junction of the Y-type micromixer to improve the mixing between ferro-nanofluid and water. The permanent magnet is 9.6 mm long, 9.6 mm wide and 1.6 mm thick. Equal volumetric flow rates for both ferro-nanofluid and water were tested in two different channel widths, 300 mu m and 500 mu m. Three different volumetric flow rates of 3 mu L/min, 6 mu L/min, and 10 mu L/min were analyzed to determine the effect of flow rate on the mixing of fluids in the micromixer. Since Fe3O4 nanoparticles in the ferro-nanofluid are strongly affected by a relatively uniform magnetic field from the permanent magnet, measured results show that a rapid mixing between ferro-nanofluid and water can be achieved immediately downstream of the permanent magnet for all volumetric flow rates and all channel widths tested in this study. (C) 2009 Elsevier B.V. All rights reserved.