Double-diffusive natural convection within a 3D porous enclosure, using the boundary element method

Abstract

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.A three-dimensional numerical study based on the boundary element method (BEM) was performed in order to study the problem of double-diffusive natural convection within a cubic enclosure filled with a fluid-saturated porous media, and subjected to horizontal temperature and concentration gradients. The fluid-flow within the porous media was modeled using space-averaged Navier-Stokes equations, coupled with energy and species equations. The used numerical algorithm is based on a combination of single domain and sub-domain BEM, and solves the velocity-vorticity formulation of the governing equations. The influences of the main controlling parameters, such as the porous Rayleigh number, Darcy number, Lewis number, and the buoyancy coefficient were investigated, by focusing on those situations, where the flowfield becomes 3D. The results for overall heat and solutetransfer through the porous enclosure are presented in terms of Nusselt and Sherwood numbers as functions of the governing parameters, and then compared to the numerical benchmarks published in literature.