Electrokinetically-driven non-Newtonian fluid flow in rough microchannel with complex-wavy surface

A numerical investigation is performed into the flow characteristics of electrokinetically-driven non-Newtonian fluids in rough microchannels with a complex-wavy surface. In performing the simulations, the flow behavior of the non-Newtonian fluids is characterized using a power-law model and the complex-wavy surface is modeled via the superimposition of two sinusoidal functions. The simulations examine the respective effects of the flow behavior index, the non-dimensional Debye–Huckel parameter, and the complex wavy-surface geometry parameters on the flow field characteristics, volumetric flow rate and electric field intensity. The results show that the flow behavior of non-Newtonian fluids is significantly dependent on the value of the flow behavior index in the power-law model. Specifically, the volumetric flow rate increases as the flow behavior index reduces. For a pseudoplastic fluid, the volumetric flow rate increases with an increasing value of the non-dimensional Debye–Huckel parameter due to the corresponding reduction in viscosity. By contrast, for a dilatant fluid, the volumetric flow rate reduces as the Debye–Huckel parameter increases. Finally, it is shown that the velocity profile near the complex wavy surface is more sensitive to changes in the waveform geometry than that in the center of the channel. Overall, the results presented in this study provide a useful insight into the manipulation of non-Newtonian fluids within real-world microchannels characterized by surface roughness.

► The rheological behavior is characterized using a power-law model. ► The flow behavior index has a significant effect on the flow field characteristics. ► The volumetric flow rate increases as the flow behavior index reduces. ► Non-dimensional Debye–Huckel parameter affects the volumetric flow rate. ► The velocity near the wavy surface is more sensitive to changes in the waveform.