Bidispersive Porous Media

Abstract

There has been much recent interest in so called double porosity materials. This is where a solid body may have a double porosity structure. There is a macro porosity but also a micro porosity which may be linked with fissures in the solid skeleton. Such double porosity materials are important in the field of elasticity due to applications in land slides, civil engineering, or even in bone. Theoretical approaches to modelling double porosity materials have a long history. Stability and uniqueness studies for theories of double porosity materials have been given together with acceleration wave analyses. Double porosity materials have been of interest in the field of chemistry for some time where such materials are also known as bidispersive. Bidisperse porous media have been studied within the context of use as a catalyst in the production of high octane petrol. Bidisperse porous media and in particular the nano-scale pore structure have been found to be important in other areas of fuel production, especially in coal. In the light of the many applications for bidisperse porous media, theories of fluid flow through a doubly porous body, or a bidispersive porous body, have been gaining impetus in recent years. In this chapter we discuss thermal convection in a bidisperse porous medium of Brinkman type. We also discuss thermal convection in a bidisperse porous medium of Darcy type. Furthermore, we discuss a model for thermal convection in a porous medium of tridispersive type.