Etude hydrodynamique et thermique d’un écoulement en régime laminaire dans une conduite remplie par un milieu poreux.

Abstract

The present work involves the thermal numerical simulation of laminar forced convection inside an annular pipe completely filled porous material. The DarcyBrinkman-Forcheimer- model is considered to describe the fluid transport in the porous media. The energy transport is simulated using the LTNE model: Local Thermal Non-Equilibrium between the fluid and the solid phases. The final form of the governing equations with their boundary conditions are transformed in dimensionless form and discretized by the finite volume method. SIMPLE algorithm was adopted to solve the set of algebraic discretized coupled equations. This work is divided in two parts: In the first part, the effect of the pertinent dimensionless parameters which govern the study such as Biot number (Bi), Reynolds number (Re), solid-fluid thermal conductivity ratio (Rc) and porosity ( ) on the LTNE intensity are analyzed by calculating the local difference of temperature (LDT) and the average difference of temperature DMT. The results show that the increase of Biot number and the solid-fluid thermal conductivity ratio, porosity and the decrease of Re reduces the LTNE intensity. The intensity of the LDT in the developing region is greater than that of the fully developed region. It is difficult to achieve a thermal equilibrium between the solid and fluid phases except in the case of high values of the Bio number. Therefore, the use of the thermal equilibrium model is not suitable in most cases. In the second part, the thermal performance is studied, the results illustrate that the increase of Bi, and Rc, and the decrease of porosity, Rr and Re represent good factors to improve the thermal performance.