Natural convection in a partially open-ended porous squarecavity

Natural convective heat transfer in an open-ended porous square cavity is studied numerically in the present article. The left surface has a constant temperature and the right surface is a partial opening to the ambient, permitting air to flow inside the cavity by virtue of buoyancy, while the outer surfaces are all insulated. The Forchheimer-Brinkman-extended Darcy model is used in the mathematical formulation for the porous layer, and the COMSOL Multiphysics software 4.1 is applied to solve the dimensionless governing equations. P2-P1 lagrange elements and Galerkin least-square are used to assure the stability. The governing parameters considered are the aperture size, 0.3 ≤ H ≤ 1, the thermal conductivity ratio of solid matrix to fluid (1 ≤ k_s/k_f ≤ 20), the porosity of porous medium, 0.4 ≤ ε' ≤ 0.99, and the Rayleigh number, 10³ ≤ Ra ≤ 10 ⁶. The results are presented to show the effect of these parameters on the fluid flow and heat transfer characteristics. It is found that the strength of the flow circulation and heat transfer rate are much higher for a larger opening. It is also found that the heat transfer enhancement by increasing the opening can be scaled directly from the porosity value.