Developing a fast and tunable micro-mixer using induced vortices around a conductive flexible link

This paper presents a numerical study of a micro-mixer based on the continuous deformation of a conducting flexible link. The induced vortices around the link enhance the mixing process. This micro-mixer consists of one straight microchannel and one conductive flexible link. One end of the link is fixed on the upper wall of the channel and the other end can move freely due to the fluid-solid interactions. Since this link is conductive, vortices form around the link (once the electric field is applied). Applying a time-varying DC electric field causes variation in the applied forces to the link; thus, the link will swipe the channel and acts as a micro-stirrer to enhance mixing results. The presented results show that there is a direct relationship between mixing efficiency and the length of the link, as well as the amplitude of time-varying DC electric field. The effects of Young’s modulus, the average of applied electric field, and link position are also studied. Link with lower Young’s modulus swipes larger area inside the channel and enhances the mixing efficiency. By increasing the length of the conductive link, large vortices will be induced around it and mixing efficiency enhances. Our numerical results show that average mixing efficiency of link with a length of L = 0.625 W = 156.25 μm is about 90%. The proposed micro-mixer is simple to be fabricated and mixes the fluid streams in a short period of time with high efficiency. Such micro-mixers can be used in various microfluidics, biomedical, or chemical applications.