Mixing and heat transfer in micro/nano-channel due to charged corrugated surfaces

Abstract

Fluid transport and mixing analysis is performed numerically in micro/nano-channels, where the channel walls are fabricated with separated charged blocks. Two different streams of miscible fluids with different concentrations are supplied through the inlet port with an external applied electric field. The fluid is flowing under low Reynolds numbers experiences convection and diffusion effects which promote the desired mixing. In this paper theory of dynamic equations are used for the time scales with the coefficient as zero linear growth. Both Joule heating effects and pressure variation is considered for the fluid transport using a lubrication theory approximation, considering the combined formulation of the Navier-Stokes and Nernst-Planck model for electromigration. It is observed that axial pressure variation are maximum above the heterogeneous regions providing a zero gradient along the fully-developed regions. The diffusive transport of thermal energy for an unaltered wall temperature can be enhanced due to the augmentation of the local fluid temperature with the applied electric field. It is observed that wall heterogeneity creates a high convective zone in the diffuse layers resulting complex flow structures of fluids and ions. The improvement of ion transport in the species layers at different horizontal positions significantly enhance the mixing rate.