Analysis of a Square Split-and-Recombined Electroosmotic Micromixer with Non-aligned Inlet-Outlet Channels

ABSTRACT In micro-scale sensitive medicinal and biochemical systems, improving mixing efficiency with small velocity limitations is critical. This work examines the influencing key parameters and their implications on mixing efficiency in a new two-dimensional electroosmotic micromixer (EM) with nonaligned input and outlet microchannels. The micromixer uses electroosmosis force generated by microelectrodes mounted on the walls of a square split and recombine (SSAR) mixing chamber to blend fluids of various concentrations, which enter into an intake microchannel from different inlets. The governing equations along with the specified boundary conditions are solved by the finite element-based solver. Thorough investigations are executed to explore how the mixing performance of the new microchannel mixer is affected by both flow (inlet velocity) and electric field (electrode potential arrangement, voltage magnitude, AC frequency, and phase difference) parameters. The results revealed that only adding electrode pairs always doesn’t increase the mixing efficiency of SSAR-EM, rather electrode polarity configuration along with an increase in electrode pair optimizes fluid mixing. Also, according to the present observations, the mixing performance of SSAR-EM is strongly sensitive to the input fluid velocity, the phase difference applied to the micro-electrodes, the AC frequency, and the amplitude of the alternating voltage. Corresponding to optimal parameters (i.e. velocity of 50 µm/s, AC-frequency of 8 Hz, voltage of 100 mV, and phase difference of 7π/36-radian), the mixing efficiency of SSAR-EM becomes 98.26%.