Numerical Study of Natural Convection Flow in a Square Cavity with Linearly Heating on Bottom Wall Using Copper-Water Nanofluid

The problem of natural convection fluid flow and heat transfer of Cu-water nanofluid inside a square cavity has been investigated numerically. The cavity has been bounded by adiabatic top wall, constant temperature cold vertical walls and a horizontal bottom wall. The bottom wall is subjected to constant and linearly varying temperatures. The nanofluid is assumed to be incompressible. Calculations were performed for Rayleigh number (103 = Ra = 105) and volume fraction of nanoparticles (0, 0.025 and 0.05). Results are presented in the form of stream lines, isotherm plots and average Nusselt numbers. It is observed from this study that the uniform temperature at the bottom wall gives higher Nusselt number compared to the lineary varying temperature case for ? = 0, 0.025 and 0.05 for bottom wall. For a given Rayleigh number an increase of volume fraction of nanoparticles causes an increase of the mean Nusselt number, but this increment is high for the case of constant temperature. This problem may be occurred in a number of technical applications such as solar energy collection and cooling of electronic equipment and chips using nanofluids.