Electro-osmotic Flow of Non-Newtonian Biofluids Through Wavy Micro-Concentric Tubes

Abstract

Most biofluids are non-Newtonian fluids with complex flow behaviors; for instance, human blood and DNA samples are shear thinning fluids (Jeffery model). The electro-kinetic transport of such fluids by microperistaltic pumping has been a topic of interest in biomedical engineering and other medical fields. This type of fluid transport requires sophisticated mathematical models and numerical simulations. Motivated by these developments, this study analyzed the simultaneous effects of an electric double layer (EDL) and a transverse magnetic field on the peristaltic flow and transport of blood. However, electro-osmotic flow is most significant when in micro channels/tubes. A constitutive relation is proposed to describe the electro-osmotic flow in the gap between two micro-coaxial horizontal pipes. Under low Reynolds number, long wavelength and Debye linearization approximations, the Poisson-Boltzmann equation, and governing equations are derived with the appropriate boundary conditions. The expressions for the electric potential, stream function, axial velocity, shear wall stress, and axial pressure gradient are obtained. The pressure rise and frictional force per wavelength are numerically evaluated and briefly discussed. The computational evidence suggests that the electric potential is an increasing function of the EDL thickness. Additionally, axial flow is accelerated by a positive electric field and decelerated by a negative electric field. Finally, the bolus size is reduced as the axial external electric field changes from the positive to negative direction.