With the development of aeronautics and astronautics

more and more attention has paid to efficient heat transfer inside a tube. Metal foam has a large specific surface area and high thermal conductivity

which are suitable for enhancing the flow boiling heat transfer. In this study

the effect of the metal foam structure on the flow boiling heat transfer in tubes was studied experimentally. The experimental conditions covered a pore density of 10–40 pores per inch (PPI)

vapor quality of 0.1–0.9

mass flux of 90–180 kg/(m2·s)

and a heat flux of 12.4–18.6 kW/m2

and the wettability of the hydrophobic or uncoated surfaces. The experimental results show that the heat transfer coefficient of the 40 PPI metal foam tube is up to 96% higher than that of the of the 10 PPI metal foam tube. With an increase in vapor quality

mass flux

and heat flux

the flow boiling heat transfer in the metal foam filled tube is increased by a maximum of 74%

95%

and 48%

respectively

and hydrophobic modification increases the number of nucleate sites on the metal foam surface

resulting in a heat transfer enhancement of 10%–30%.