Mixing Enhancement in Electroosmotic Micromixers

Abstract

Micromixers have important applications in various pharmaceutical and medical fields. In the present study, the enhancement of mixing index in electroosmotic micromixer with different geometries is investigated. The commercial software COMSOL Multiphysics 5.4 is employed to solve the mathematical models. The SIMPLEC algorithm is employed for coupling the velocity and pressure fields. A second-order upwind scheme is used to reduce the artificial diffusivity. The results show a remarkable effect of the electric field on the mixing efficiency. The optimum geometry is the one with no obstacle in the mixing chamber. For the optimum geometry, it is demonstrated that the mixing efficiency increases with the voltage, however there are optimum values for frequency and inlet velocity in which the micromixer exhibits its best performance. The optimum values of frequency and inlet velocity are 8 Hz and 0.1 mm/s, respectively. It is revealed that the micromixer with no obstacle can reach the mixing efficiency of about 97%.

Micromixing and microparticle separation: A review

“…They have employed passive and active techniques. Magnetic field [5,6,8,10], acoustic field [7,18], and electrophoresis [9,11,16,17] are three types of active methods that improve mixing efficiency. It can be found that molecular diffusion is dominant when Re is low and chaotic advection plays a major role when Re is high.…”

Micromixing of deionized water and plasma using square-wave microchannels

“…To improve the mixing quality, various active and passive techniques have been utilized by many researchers [2]. Passive methods do not employ external energy sources, while active techniques, such as magnetophoresis [3][4], acoustic force [5][6], electroosmosis [7], etc., utilize external actuators.…”