Abstract
The non-homogenous two-phase Buongiorno's nanofluids model is applied to investigate the convection process within cubic enclosures filled with homogenous/heterogeneous porous medium. The homogenous/heterogeneous properties are considered in the overall permeability and thermal conductivity of the porous elements. Different cases upon the type of the medium are considered, namely, homogeneous porous domain, heterogeneous porous domain in all directions, heterogeneous cavity with stratification in X-Y plane, heterogeneous cavity with stratification in X-Z plane and heterogeneous cavity with stratification in Y-Z plane. The worked mixture is Al2O3-water nanofluid and the Brownian motion parameters, the thermophores parameter and the dynamic viscosity are variables. The SIMPLE algorithm together with the finite volume method are extended to the three dimensional case and applied to treat the governing equations. It is remarkable that the heterogeneous case in all directions (eta(1) = eta(2) = eta(3) = 1:5) gives the largest values of the average Nusselt coefficient while the homogenous case has the lowest rate of the heat transfer. In all the considered porous cases, the growing in the Rayleigh and Darcy numbers enhances the average Nusselt number. (C) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).