Investigation of the Effect of Velocity Slip and Temperature Jump on the Heat Transfer of Nanofluid in a Microchannel Under Constant Heat Flux with Lattice Boltzmann Method

In this article, the effect of velocity slip and temperature jump on the flow and heat transfer characteristics of Al2O3 – Water nanofluid in a microchannel with insulated upper wall and constant heat flux on the lower one, is investigated using the lattice Boltzmann method. The problem is solved at Re equal to 5, for base fluid and nanofluid with 0.02 and 0.04 volume fractions, no-slip and slip conditions with 0.04 and 0.1 slip coefficients and also at 5 to 50 nm nanoparticle diameters. The results show that, in general, using the hydrophobic surfaces in addition to making a considerable reduction in wall shear stress, somewhat increases the heat transfer efficacy at uniform wall heat flux condition that can not be seen in the constant wall temperature situations. Also, it is shown that the effect of temperature jump on the average Nusselt number, is more for base fluid than the nanofluid and increases for higher slip coefficients. For nanofluid with 0.04 volume fraction, the average Nusselt number increases continuously with slip coefficient but, for base liquid, firstly it increases and then decreases.