Porous media to intensify natural convection in rectangular enclosures used in building techniques

Abstract

This numerical study quantifies the natural convective heat transfer occurring in an elongated rectangular cavity whose hot vertical wall generates a constant heat flux while the opposite one is kept isothermal at cold temperature. The study shows that when a layer of porous material is affixed to the hot wall, the aerodynamic phenomena are modified and increase the natural convective transfer. Several configurations were processed, obtained by varying the matrix’s thermal conductivity of the layer, the aspect ratio of the cavity and the Rayleigh number in wide ranges. The numerical solution is obtained by means of the control volume method based on the SIMPLE algorithm. A correlation of the Nusselt–Rayleigh type is proposed, allowing determination of the convective heat transfer for any combination of these physical parameters. It can be applied in various engineering fields including passive heating in building which can be improved by the simple and easy-to-implement assembly version discussed here.