Fabrication and characteristic study on mixing enhancement of a magnetofluidic mixer

Abstract

The needs for fast mixing of two miscible fluids in microfluidic device is increasing recently and has been widely used for DNA synthesis, clinic diagnostics and chemical reaction. However, the mixing at microscale relies heavily on slow molecular diffusion because of its low Reynolds number and thus laminar flow. In this work, therefore, a magnetofluidic mixer with the integration of magnetic field is presented for rapid mixing between ferrofluid and distilled water with no harmful Joule heat generated. Parametric study of experiment and simulation was performed to discuss the effect of flow rate, placement angle of magnet and width of magnet on the mixing efficiency between two fluids. It was found that the mixing performance of 0.76 was the most homogeneous when the angle α = 1/12π because of the acceleration-deceleration couples (ADC) and mass conservation law. It was also found that the mixing performance increases from 0.13 to 0.49 as the magnet width increases from wm=50μm to wm=250μm while decreases when magnet width is wider than wm=250μm due to local reduced Peclet number. The developed micromixer and mixing mechanism will be of great potentials and insight for future quick optimization of biomedical and chemical mixing devices.