Investigation of the performance of a pulsatile flow micromixer coupled with ICEO

In this study, the characteristics of two miscible liquids are investigated under pulsatile flow conditions along a microchannel with certain obstruction width numerically. The types of fluid are defined as Newtonian, power-law, and Carreau. Although micromixing capability can be enhanced using pulsation and obstruction, induced-charge electro-osmosis (ICEO) is needed for acceptable mixing efficiencies at desired time and length. The ICEO electrode is defined on the top side of obstructtion. Mixing indexes are plotted concerning the magnitude of external potential difference, width and length of the obstruction and frequency of pulsatile flow. Streamlines and concentration maps are presented for various magnitude of external potentials. Mixing performances during the last period of pulsatile flow are plotted according to the width and length of ICEO electrode for each external potential difference, as well. The effects of pulsation frequency on average mixing indexes are demonstrated for various obstruction widths. It is observed that mixing performance is increased with the external potential difference due to strong ICEO vortices. However, this situation is not evident, when an obstruction is present. The extended length of ICEO electrode significantly diminishes time-dependent variations in mixing indexes. Mixing index is increased using pulsation frequency until the frequency of f=1Hz and then decreased. When the obstruction width increases, higher mixing indexes are obtained for smaller frequency values compared to f=1Hz. As a result, mixing indexes of 99% and 94% are successfully obtained using correct parameter combinations for Newtonian and non-Newtonian fluids, respectively.