Numerical Simulation for efficient mixing of Newtonian and non-Newtonian fluids in an electro-osmotic micro-mixer

• Effect of various parameters on fluid mixing in an electro-osmotic micro-mixer is observed.
• Three types of device geometries were modeled: one-ring, diamond and two-ring types.
• As the voltage amplitude of the electrodes increases, higher mixing quality is achievable.
• An intermediate 4 Hz frequency contributes to a higher mixing quality.
• Remarkable mixing quality has been achieved for the Newtonian and non-Newtonian fluids.

The present study, deals with a new mixing technique using a two-phase electrode array, which is charged with alternating current (AC) signals, located in specific parts of the geometry. This significantly contributes to a chaotic mixing mechanism using a low amplitude AC voltage within a micro-channel. Study analysis demonstrates that the optimization of the effective parameters such as geometrical features, voltage amplitude, fluid inlet velocity, AC frequency and phase lag for a defined fluid can lead to an optimum and highly efficient mixer by considerably increasing disturbances in a primary highly ordered laminar flow. Three different geometries of micro mixer are studied; one-ring type, diamond type and two-ring type and it is shown that the optimum mixing quality of 99.4, 98 and 99.8% are achievable for them, respectively. Finally all the aforementioned studies have also been done for the case of blood as a biological fluid.