To obtain the effect of lubricating oil on the heat transfer characteristics of supercritical carbon dioxide under heating conditions

the flow and heat-transfer model of CO2/lubricating oil two-phase mixture was established by using Fluent software. The model was used to analyze the heat transfer characteristics in detail at different oil concentrations

mass fluxes

heat fluxes and operation pressures. The results show that the presence of lubricating oil significantly weakened the convective heat transfer process of supercritical carbon dioxide. With the increase of lubricating oil concentration

the convective heat transfer was further deteriorated. The concentration of lubricating oil had a marked impact on the heating characteristics of supercritical carbon dioxide. When the oil concentration was less than 1%

the change trend of heat transfer coefficient was not affected. When the oil concentration exceeded 3% and the temperature was higher than the pseudo critical temperature of carbon dioxide

the degree of heat transfer deterioration decreased. The increase of heat flux made the convective heat transfer worse

but increasing the mass flux can effectively improve the phenomenon of heat transfer deterioration. The solubility of carbon dioxide in lubricating oil directly affected the convective heat transfer process. The increase of operating pressure can enhance the solubility of carbon dioxide in lubricating oil which contributed to reducing the degree of heat transfer deterioration under high lubricating oil concentration.