Abstract: Based on the double boundary layer model, this work established a laminar condensation heat transfer model of steam with CO₂ on a vertical plate. The condensation heat transfer performance is deteriorated greatly due to the presence of CO₂. At a certain concentration of CO₂, with the increase of surface sub-cooling, the heat flux increases, the heat transfer coefficient decreases, and the interface temperature decreases almost linearly. With the increase of CO₂ concentration, the heat transfer coefficient decreases rapidly while the interface temperature increases gradually. In addition, the presence of CO₂ results in the formation of a layer of gas film outside the liquid film. With the increase of surface sub-cooling, the thickness of liquid film increases and the thickness of gas film decreases. Hoowever the thickness of the gas film is one order of magnitude larger than that of the liquid film. With the increase of CO₂ concentration, the thicknesses of liquid film and gas film both increase. However, the thermal resistance ratio of gas film to liquid film increases gradually, and the gas thermal resistance becomes dominant at high concentrations of CO₂.

Key words: CO₂, vapor mixture, condensation heat transfer, non-condensable gas