Introduction to Fluid Flow and Heat Transfer in Porous Media

Abstract

Porous materials (media) are solids that are permeated by a network of pores. The interconnection of the pores allows the flow of one or more fluids through the material. Porous materials exist widely in nature and made industrially. Sandstone, limestone, rye bread, wood, and the human lung could be exemplified as natural porous media. Man-made porous media include metallic and non-metallic foams, porous ceramics and packed bed, which are widely used in industrial applications. Metallic foams are mostly used in heat exchangers, and packed beds are utilized for thermal storage applications. The Introduction of Chapter 1 deals with the fundamental concepts of fluid flow and heat transfer in porous materials. It covers a wide range of aspects of porous media from porosity and permeability to some unresolved issues in modeling of transport in porous media, including interface modeling between clear (fluid) region and solid region, heat flux splitting, and heat flux bifurcation phenomenon. For fluid flow in the media, some comparison between experimental and theoretical studies is conducted revealing that for a high Reynolds number (more than unity), the well-known Ergun relation could not fit well with experimental data. Convective and radiative heat transfer in porous materials are presented. Both local thermal equilibrium (LTE) and local thermal non-equilibrium (LTNE) models for convection in the media are discussed.