Heat transfer and pressure drop of refrigerant flow boiling in metal foam filled tubes with different wettability

•New data of flow boiling in metal foam filled tubes with various wettability are obtained.•Heat transfer and pressure drop characteristics in metal foam filled tubes are analyzed.•Effect of surface wettability on flow boiling characteristics are discussed.•New heat transfer and pressure drop correlations reflecting the effect of wettability are developed. Surface wettability has a significant effect on the flow boiling heat transfer coefficient in metal foam filled tubes. In the present study, the flow boiling characteristics of metal foam filled tubes with different wettability were experimentally investigated, covering the surface wettability of uncoated, hydrophobic and hydrophilic surfaces. The results showed that, for the hydrophilic metal foam filled tubes, the heat transfer coefficient and pressure drop are decreased by 2%–18% and 4%–15%, respectively than those for the uncoated ones; for the hydrophobic metal foam filled tubes, both the heat transfer coefficient and pressure drop are larger than those for uncoated ones, and the increments in the heat transfer and pressure drop are 6%–30% and 8%–35%, respectively. Based on the experimental data, the correlations for heat transfer and pressure drop of flow boiling in metal foam filled tubes with different wettability were developed with the deviations of ±6.4% and ±9.7%, respectively.