Experimental study of the effect of metal foams on subcooled flow boiling heat transfer of water and developing a correlation for predicting heat transfer.

• Subcooled flow boiling heat transfer of water in the porous metal foam tubes was investigated experimentally. • Filling a tube with metal foam could improve the heat transfer and also pressure drop. • The thermal efficiency of metal foam tubes was investigated. • Based on experimental data, a correlation was presented to predict heat transfer in the metal foam pipes. This paper has investigated the effect of different porosities (0.80–0.90) of the metal foam pipes on heat transfer coefficient and pressure drop of subcooled flow boiling of water experimentally. The metal foam pipe with 0.80 porosity has increased the Nusselt number and pressure drop by 41 % and 21 % compared to the 0.90 metal foam pipe, respectively. The heat transfer of water phase change in a porous medium has received less attention due to the complexities of the problem. One of the challenges in this field is the absence of a correlation for predicting heat transfer in metal foams. In this paper, a systematic method based on dimensionless numbers considering the essential parameters, like mass flux, subcooling, and heat flux, was used to provide a correlation for calculating the Nu-number based on 106 experimental points. The mean absolute deviation (MAD) of the results predicted by the new correlation is 8.9 %, and it predicts 95 % of the database with ±20 %. [ABSTRACT FROM AUTHOR]