Mixing features in an electromagnetic rectangular micromixer for electrolyte solutions

Abstract

In this study, a new magnetohydrodynamic (MHD) mixer for electrolyte solutions with pumping function is reported, and the mixing performance of the device for two different electrolyte solutions is numerically examined in a uniform magnetic field. Application of different potentials to different electrodes allows the current to be induced. The combination of the induced current and magnetic field yields Lorentz force, resulting in the fluid motion. The numerical simulation for the flows in the device is carried out with commercial software CFX. The validity of CFX code for the present numerical model is presented. The mixing performance of the fluids is investigated in many different cases with different combinations of input voltage of the electrode. This study shows that the mixing performance can be enhanced by applying spatially alternating positive and negative voltages to the electrodes. The present simulation results show that with a magnetic field intensity lower than 0.5 T, a voltage difference smaller than 2.0 V, and an electric conductivity of electrolyte solution of 1.5 S/m the pumping capabilities ranging 1.6×10⁻⁷−3.6×10⁻⁶ kg/s and the mixing indexes higher than 0.90 can be obtained with sophisticated designs of the micromixer.