The effect of microchannel width on mixing efficiency of microfluidic electroosmotic mixer

Abstract

This study is focused on electroosmetic micromixer and the effects of driving force are investigated in the sense of different mixing channel width schemes. Two pairs of electrodes are mounted on the sidewalls of mixing channel to provide the required electric field. Various Numerical simulations are performed to assess the fluid flow in the presence of the electrokinetic driving force. Throughout the simulation, amplitude of the applied field and the flow rate in the mixing channel are kept constant while the width of channel and distance between facing electrodes mounted on the sidewalls of channel are swept within 100 μm to 300 μm with 50 μm increment steps. Results are extracted in terms of mixing efficiency for steady and transient state. It is proved that the width of mixing channel has significant impact on the performance of micromixer due to the corresponding change in effective electric field distribution and driving force along the mixing chamber. Maximum mixing efficiency of 74.8% is achieved at 100 μm channel width and normalized electric field of 3.2 × 104 V/m peak along the horizontal center line. Finally, a fabrication method with three dimensional electrodes on the sidewalls of mixing channel is demonstrated. This achievement shows that electroosmotic micromixers would have numerous applications following current trends toward nanofluidics and nanotechnology.