Numerical investigation of magnetic field effect on nanofluid heat transfer in microchannel with hydrophobic surface using incompressible pre conditioned lattice Boltzmann method

Abstract

The flow concerning water/alumina nanofluid is studied by pre-conditioned incompressible version of Lattice Boltzmann method. The geometry at hand is a rectangular microchannel. The volume fraction of the nanoparticles is in the range of 0–2%. The present study aims to combine the heat transfer enhancement methods such as application of smooth surfaces with a slip velocity coefficient of 0–0.06 and linear magnetic field with Hartmann number of 0–40. The results of this study show that as the wall slip increases, the amount of solid blocking the fluid motion decreases. Hence, the fluid moves with less momentum drop and it moves the path along the microchannel with less momentum dissipation. Upon applying a linear descending magnetic field to a flow, the Lorentz force and the flow behavior will change. It can also be concluded that Lorentz force reduces the slippage of the fluid layers. This will eventually reduce the effects of the hydrodynamic boundary-layer and the formation of the viscous regions. As this coefficient increases, the fluid flows easier, and the effects of the isotherms penetration in the central region of the flow can be smooth. The wall slip presence in the microchannel has also boosted the motion of the fluid and reduced the velocity gradients due to the presence of solid surfaces.