This paper presents a numerical study of fully developed turbulent heat transfer in a flat channel half filled with porous material; the simulated fluid is air while an aluminium foam represents the solid matrix. The main focus is on heat transfer performances of a porous wall, the interface between a saturated porous medium and the clear fluid, in forced convection conditions; in the fluid portion a turbulent regime with a Reynolds number based on the mean velocity and the hydraulic diameter Re=9000 is sustained. The Nusselt number and the efficiency computed on the porous wall is sensibly higher than the flat wall value and this is in direct relation with the presence of a higher peak of the wall-normal turbulent heat flux.