Investigation of mixing performance in electro-osmotic micromixers through rigid baffle design and parameter optimization.

Abstract

Electro-osmotic micromixers constitute a specialized class of active micromixers that apply alternating current (AC) to electrodes. This methodology promotes the formation of vortical structures within the fluid medium, resulting in a substantial increase in mixing homogeneity. In this study, the geometrical parameters of the electro-osmotic micromixer, for which two rigid baffles were implanted at the entrance, were optimized using the Taguchi method and response surface methodology (RSM). Data were obtained through a transient 2D model, simulated using COMSOL software based on the finite element method. After acquiring the optimized geometric parameters, the mixing index was assessed under various conditions, including inlet velocity, frequency, voltage, and phase lag of the alternating current. The optimized values of first baffle angle ([Formula: see text]), second baffle angle ([Formula: see text]), baffle length (L), the distance between baffles in the x direction (x), the distance between baffles in the y direction(y), and mixing chamber angle (α) were obtained [Formula: see text] and resulted in a 10.58% improvement in the mixing process index. The implementation of rigid baffles improved the mixing index by 8%. Furthermore, increasing the applied voltage from 1 to 3 V resulted in a 27% average enhancement of the mixing index. A maximum mixing index of 99.37% was achieved at a [Formula: see text] phase lag, representing an average 20.1% improvement compared to the absence of a phase lag. This reflects an approximate 65% increase at the initial stage compared to the scenario without any phase lag.