Peristaltic pumping of hybrid nanofluids through an asymmetric microchannel in the presence of electromagnetic fields

Abstract

Motivated by applications in bio-thermal-inspired smart electro-osmotic nanofluid micro-pumps, a mathematical
\nmodel is developed to investigate the electroosmotic magnetohydrodynamic flow of hybrid nanofluids through an
\nasymmetric microchannel. The Tiwari-Das hybrid nanofluid model is employed in this article. The effects of Joule
\nheating are included in the governing equation. Nanoliquid thermal conductivity and viscosity are computed with the
\nMaxwell and Brinkmann correlations. To study the performance of hybrid nanofluids, five different nanoparticles
\nwith water as the base fluid are considered i.e. titanium dioxide, alumina, copper, copper oxide and silver as the
\nmetallic nanoparticles. The boundary conditions feature velocity slip and thermal slip. Debye-Hückel linearization is
\nemployed for the electric distribution equation. Analytical solutions are derived by the power-series based Homotopy
\nperturbation method (HPM), which is compared with MATLAB solutions (bvp4c solver). The influence of key
\nnanoscale parameters on the pumping characteristics, axial velocity and nanoparticle temperature in the asymmetric
\nmicro-channel are visualized graphically. Higher Joule electrical heating parameter reduces pressure gradient values
\nwhereas increasing Brinkman number (viscous heating) elevates pressure gradient. Higher volume fraction suppresses
\npressure gradient. For water - copper oxide nanofluid, the pressure gradient decreases with increasing Hartmann
\n(magnetic) number. Silver-water nanofluid achieves the greatest enhancement in thermal conductivity. The
\ncomputations are relevant to bio-inspired electrokinetic nanofluid micropump designs and also to the fluid dynamics
\nof soft robotics.