Numerical Modeling of Natural Convection of a Nanofluid Between Two Enclosures

Natural convection fluid flow and heat transfer between two enclosures filled with a water-based nanofluid (mainly Cu-water nanofluid) has been investigated numerically using the finite difference method. A parametric study is conducted and the effects of pertinent parameters such as the Rayleigh number, the aspect ratio of the two intertwined enclosures, and the volume fraction of nanoparticles on the flow and temperature fields and the rate of heat transfer inside the enclosure are investigated. It is found from the obtained results that the mean Nusselt number increases with the increase in the Rayleigh number and the volume fraction of nanoparticles regardless of the aspect ratio of the enclosure. Moreover, the obtained results show that the rate of heat transfer increases with decreasing values of the aspect ratio of the cavity. Also, it is found that the rate of heat transfer increases with the increase in the nanoparticles volume fraction. In addition, at low Rayleigh numbers, the effect of nanoparticles on the enhancement of heat transfer for narrow enclosures is more than that for wide enclosures.