Transient conjugate heat transfer in a porous medium in concentric annuli

Transient conjugated forced convection in the thermal entry region of a thick-walled annulus, filled with a homogeneous and isotropic porous medium, has been numerically investigated using finite-difference techniques. Non-Darcian effects as well as axial conduction of heat have been considered. The flow is assumed to be hydrodynamically fully developed and steady but thermally developing and transient. The thermal transient is initiated by a step change in the prescribed isothermal temperature on the outer surface of the external tube of the annulus while the inner surface of the internal tube is kept adiabatic. A parametric study is carried out to explore the effects of the Darcy number, the inertia term, the Peclet number and the porous medium heat capacity ratio on the transient thermal behavior in a given annulus.