Transient natural convection heat transfer by double diffusion from a heated cylinder buried in a saturated porous medium

Abstract

This paper presents numerical solutions for the transient natural convection heat transfer by double diffusion from a heated cylinder buried in a saturated porous medium where both, the cylinder and the medium surfaces, are kept at constant uniform temperature and concentration. This situation occurs, for instance, in buried electrical cables, where the ground is the main responsible for the dissipation of heat generated by the electrical cable, where in many cases the cable surface temperature may reach a dangerous limit in a very short time, even before a steady state is attained. Governing equations are expressed in bi-polar coordinates in the stream function formulation and handled numerically by a control volume method. Heat and mass transfer are studied as a function of Rayleigh, Lewis and the buoyancy ratio numbers. (c) 2005 Elsevier SAS. All rights reserved.