Numerical investigation of turbulent flow in an annular duct partly filled with a porous substrate

The paper is aimed at investigating the turbulent flow and heat transfer characteristics in an annular duct partly filled with a porous medium. A modified k-epsilon model for approximating the Forchheimer term in the equations of turbulent kinetic energy and dissipation rate is developed by time-averaging the general macroscopic transport equations. This model accounts for the second order approximation in the Forchheimer term. This higher order term leads to a better description of the turbulent effects of the Forchheimer term in the flow through the porous medium. The results show that the permeability has a great influence on turbulence and the effectiveness of the heat exchanger is noticeably improved for a highly conducting porous substrate.