Fig. 11 displays the effects of pore density and porosity of metal
foams on overall heat-transfer performance. The predicted value is
lower than that in the conventional model, shown in Fig. 11a and b
since the conventional uniform heat flux model is an ideal case for
amplifying the thermal performance of the heat exchanger to over
evaluate the overall heat transfer coefficient. It was indicated that
the heat transfer performance is enhanced by increasing the pore
density due to increasing of heat transfer surface area, and is weakened
by increasing porosity due to decreasing of diameter of cell
ligament.