Double-Diffusive Natural Convection in a Partially Heated Enclosure Using a Nanofluid

This paper analyzes numerically the effect of double-diffusive natural convection of a water-Al2O3 nanofluid in a partially heated enclosure with Soret and Dufour coefficients. The top horizontal wall has constant temperature Tc, while the bottom wall is partially heated Th, with Th > Tc. The concentration in the top wall is maintained higher than the bottom wall (Cc < Ch). The remaining bottom wall and the two vertical walls are considered adiabatic. Water is considered as the base fluid. The governing equations are solved by the Penalty Finite Element Method using Galerkin's weighted residual scheme. The effect of the parameters, namely, Rayleigh number and solid volume fraction of the nanoparticles on the flow pattern and heat and mass transfer has been depicted. Comprehensive average Nusselt and Sherwood numbers, average temperature and concentration, and mid-height horizontal and vertical velocities at the middle of the cavity are presented as functions of the governing parameters mentioned above. (C) 2012 Wiley Periodicals, Inc.