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 μm and 500 μm. Three different volumetric flow rates of 3 μL/min, 6 μL/min, and 10 μL/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.