Film condensation heat transfer in the presence of an uncondensable gas

Film condensation heat transfer characteristics are studied by the numerical simulation for a single horizontal tube in the presence of an uncondensable gas. The vapor-liquid two-boundary-layer model is applied to predict the local mass concentration of the uncondensable gas, the temperature profiles and velocity profiles in the boundary layer. It is shown that the mass concentration and velocity of the uncondensable gas increase while the temperature decreases from the bulk of the vapor to the interface. The numerical predictions agree well with condensation heat transfer measurements for the steam with air as an uncondensable gas.