Magnetic field effects on nanoparticle migration at mixed convection of MHD nanofluids flow in microchannels with temperature-dependent thermophysical properties

Abstract

This is a theoretical investigation of the impact of magnetic field on nanoparticle migration at mixed convective heat transfer of nanofluids inside microchannels with temperature-dependent thermophysical properties. A modified Buongiorno's model is employed for the nanofluid which takes into account the effects of thermophoresis and Brownian motion. The Navier's slip condition is considered at the wall to assess the non-equilibrium region near the fluid–solid interface. After the fluid flow has been assumed to be fully developed, the governing equations including the continuity, momentum, energy, and nanoparticle volume fraction have been simplified to a set of ordinary differential equations and solved numerically. The results are obtained with and without considering the dependency of thermophysical properties upon temperature. It is shown that neglecting the dependency of thermophysical properties to the temperature does not significantly affect the flow fields and heat transfer behavior of nanofluids, but it changes the relative magnitudes. Furthermore, in the presence of magnetic field, smaller nanoparticles are more appropriate than the larger ones.