Author(s)

J. Kramer, R. Jecl & L. ˇSkerget

Abstract

A numerical study of double-diffusive natural convection in porous media using the Boundary Element Method is presented. The studied configuration is a horizontal layer filled with fluid saturated porous media, where different temperature and concentration values are applied on the horizontal walls, while the vertical walls are adiabatic and impermeable. Transport phenomena in porous media are described with the use of modified Navier–Stokes equations in the form of conservation laws for mass, momentum, energy and species. The results for different governing parameters (Rayleigh number, Darcy number, buoyancy ratio and Lewis number) are presented and compared with those in published studies. Keywords: Boundary Element Method, porous media, double-diffusive natural convection. 1 Introduction Transport phenomena in porous medium is a subject of intensive research in last couple decades,mainly because of wide range of applications in many engineering branches. Problems of natural convection in porous media are most commonly studied examples. Many reported studies are dealing with natural convection driven by thermally buoyancy forces. A related problem that has received less attention is the so-called double-diffusive convection, where density differences occur due to combined thermal and compositional gradients across the porous layer. Some applications, where thermal natural convection or combined doublediffusive natural convection are observed, are fibrous insulation, geothermal energy, underground spreading of contaminants, solidification processes. In horizontal layers, where horizontal walls are maintained at different temperatures and solute concentrations, the convective flow is possible above the

Keywords

Boundary Element Method, porous media, double-diffusive natural convection.