Natural convection of a nanofluid inside a square cavity

A two dimensional square cavity filled with a nanofluid and subject to side heating is here studied. The side heating condition is obtained by imposing two different temperatures at the vertical boundary walls. The horizontal walls are assumed to be adiabatic and all boundaries are considered impermeable. For the investigation of nanoparticles distribution, a non homogeneous model is taken into account. The thermophysical properties of the nanofluid are assumed to be functions of the average volume fraction of nanoparticles dispersed inside the cavity. In order to better understand the role played by the nanoparticles in the heat transfer, the definitions used for the nondimensional governing parameters (Rayleigh number, Prandtl number and Lewis number) are the same as for clear fluids. The average volume fraction of the nanoparticles is an additional parameter explicitly taken into account. The distribution of the nanoparticles shows a particular sensitivity to low Rayleigh numbers and the Nusselt number at the hot wall is sensitive to the average volume fraction of the nanoparticles dispersed inside the cavity. The solution of the problem is obtained numerically by means of a Galerkin finite element method implemented through the software package Comsol Multiphysics (© Comsol, Inc.).