Influence of varying zeta potential on non-Newtonian flow mixing in a wavy patterned microchannel

The isothermal micromixing driven by an induced charge mechanism in a wavy patterned micro-channel is numerically analyzed. The walls of the microchannel are assumed to have modulated with the zeta potentials that vary slowly along the axial direction in a sinusoidal manner. The flow field of two miscible aqueous electrolytes are characterized by power-law model and are solved numerically using finite volume method. Contrary to the commonly held belief, our results predicted that the sinusoidal charged surface leads to an increase of interfacial contact area between two streams. It is noted that, the reduction of drag force leads to an improvement in pressure gradient due to high frequency fluctuations resulting an effective mixing compared to straight channel flow. Mixing is quantified numerically through charged patterned surfaces with the increment of flow behavior index (n). It is observed that mixing efficiency is not always beneficial in terms of performance factor since the pressure drop becomes higher with the increment of power-law index (n), Debye-Huckel parameter (kappa H) and wave amplitude (a). Hence, we tried to estimate the microfluidic mixing by exploiting the optimum flow behavior indices with a controlled pressure drop.