The influence of concentration of lubrication oil and structure of metal foam on the nucleate pool boiling heat transfer characteristics of refrigerant/oil mixture on metal foam covers was investigated experimentally.Three copper foams

10 ppi/90% porosity

10 ppi/95% porosity and 30 ppi / 98% porosity with the thickness of 5 mm

were used in this study.The refrigerant is R113 and the oil is VG68 with concentrations from 0 to 5%.The experimental results indicate that the pool boiling heat transfer coefficient on copper covers is larger than that on flat heated surface

with a maximum increase of 1.6 times under the experimental conditions.The presence of oil deteriorates the pool boiling heat transfer on copper foam covers

decreased by 15% or less under the experimental conditions.The deterioration of oil on nucleate pool boiling heat transfer is less on copper foam covers than on a flat heated surface.A correlation for predicting the nucleate pool boiling heat transfer coefficient of refrigerant/oil mixture on metal foam covers is developed

and it agrees with 95% of the experimental data within a deviation of ±10%.