Application of electrokinetic instability for enhanced mixing in various micro-T-channel geometries

We present simple effective micromixer designs utilizing electrokinetic instability (EKI) with downstream cavity structures in a micro-T channel. The amount of free charge increases at each corner of the cavities where inhomogeneous flow stream meets the electric field curved along the concentration gradient. The resulting Coulombic force enhances the instability and leads to a repetitive evolutionary flow pattern from one cavity to the next, yielding a higher mixing efficiency. The mixing efficiency is found to increase by about 15% for the channel with herringbone-shape cavities as compared with the straight channel. (c) 2005 American Institute of Physics.