Authors: H.S. Seo, Y.J. Kim
Affilation: Sungkyunkwan University, Korea
Pages: 623 - 626
Keywords: microfluidic system, electroosmotic micromixer, mixing performance
Rapid and efficient mixing is important for many microfluidic applications but challenging process in many microfluidic systems that perform complex chemical synthesis and analysis. Most existing microfluidic mixing systems are limited to low Reynolds number regimes. According to scaling law, decreasing the mixing path can shorten the mixing time and enhance mixing quality. In order to achieve fast mixing, a new type of electrokinetic mixer with a ring-type channel is introduced. The proposed mixer takes two fluids from different inlets and combines them into a ring-type mixing chamber. The fluids enter a two different inlets (25 µm, respectively) and outer radii (inner radius: 25 µm and outer radius: 50 µm, respectively). The total channel length is 500 µm, the length from inlet to center of mixing chamber is 125 µm and from center of mixing chamber to outlet is 375 µm. Four microelectrodes are positioned on the outer wall of the mixing chamber. The electric potentials on the four microelectrodes are sinusoidal in time with various maximum voltage, zeta potential and frequency values. Also, in order to compared with mixing performances as configurations of obstacle in the chamber, we performed several obstacle modeling and numerical analysis using commercial code, COMSOL. The concentration, flow and electric fields in the channel were calculated and the results were graphically depicted for various flow and electric conditions.