The Effect of Variable Properties on Rayleigh-Benard Convection in an Enclosure Filled with Al2O3-EG-Water Nanofluid

In this paper, the natural convection heat transfer of Al2O3-EG-water nanofluid in a rectangular cavity which is heated from the bottom and is cooled from the top has been investigated numerically. The governing equations for a Newtonian fluid have been solved numerically with a finite volume approach using the SIMPLER algorithm. The main focus of the current study is on the effects of variable thermophysical properties of nanofluid on the heat transfer in natural convection. The influence of pertinent parameters such as Rayleigh number (Ra=105-107) and volume fractions of nanoparticles (0≤Φ≤0.05) on the heat transfer characteristics of natural convection have been studied. The results have shown that the average Nusselt number is reduced by increasing the volume fraction of nanoparticles. To study the significance of temperature effect on thermophysical properties of nanofluid, the results obtained by using variable properties of nanofluid are compared with those of constant properties.