Natural convection heat transfer in an inclined square enclosure filled with a porous medium saturated by nanofluid using Buongiorno's mathematical model

This paper presents numerical study of nanofluid free convection in a porous enclosure. Two vertical walls are maintained at constant but different temperatures. (T-h > T-c), while the remaining walls are insulated Two-phase Buongiorno nanofluid model is employed in this work considering Brownian diffusion and thermophoresis effects. Governing equations are solved using a Simple-based finite volume method. Two different nanofluids are considered in this study, i.e. Al2O3/water and Cu/water. Numerical simulations are conducted for different porous Rayleigh numbers (Ra-p = 10(2), 10(3) and 10(4)), porosities (epsilon = 0.5, 0.7 and 0.9), particle volume fractions (0 6 <= phi(Ave) <= 0.04) and inclination angle of enclosure ranging from 0 degrees to 60 degrees. Numerical results indicate that porosity plays an important role on the heat transfer rate especially at high porous Rayleigh numbers. Compared to Al2O3, Cu nanoparticles show more uniform distribution inside the enclosure. Numerical results demonstrate that there is mass boundary layer adjacent to enclosure walls and its thickness decreases by reducing porosity or increasing porous Rayleigh number. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.