Optimization of an inertial-based electroosmotic micromixer

Abstract

This paper presents a novel inertial-based electroosmotic micromixer designed for high-throughput applications in chemical and biological industries. The device features a curved microchannel that generates lateral Dean vortices, combined with a dedicated section where an electroosmotic field is applied using two pairs of electrodes. Both two- and three-dimensional simulations are conducted using the finite element-based COMSOL Multiphysics software. The results reveal that the mixing index (MI) increases with the applied DC voltage, while the effect of inlet velocity (U_in) follows a decreasing-then-increasing trend. Specifically, MI improves from around 50% to nearly 99% when the voltage is varied between 0 and 50 V, when U_in = 0.005 m/s. Additionally, the Figure-of-Merit (FoM) values obtained under the DC electric field are notably high, especially at low inflow velocities; for example, when U_in = 0.001 m/s, the FoM reaches approximately 5 with active electroosmotic forces. When an AC electric field is applied, the MI improves with increasing voltage, but optimal values for both inlet velocity and frequency emerge. For instance, the MI reaches 96.037%, 97.527%, 97.666%, 87.488%, and 81.624% at frequencies of 4, 8, 16, 32, and 64 Hz, respectively, highlighting the importance of tuning these parameters for maximum MI. This study demonstrates the potential of combining inertial and electroosmotic effects to achieve enhanced mixing performance in microfluidic devices.