The pressure drop characteristics of refrigerant-oil mixture flow boiling inside metal-foam filled tubes were investigated experimentally. The experimental fluid is R410A/VG68 oil
and the oil concentration range is 0—5%. The structure of the metal foam used in the experiments include PPI of 5 and 10
and porosity of 95%. The experimental results show that
as the oil concentration and PPI increases
the pressure drop increases. The incomplete cells nearby tube wall decreases the flow turbulence
resulting in the decrease of pressure drop
with the decrease of tube diameter
the pressure drop in metal-foam filled tubes decreases
which is different from that in smooth or microfin tubes. Based on the experimental data
the pressure drop correlation for refrigerant-oil mixture flow boiling inside metal-foam filled tubes was developed
and it can predict the pressure drop characteristics in metal-foam filled tubes with different diameters.