Condensation UDF theory: Film condensation in the presence of noncondensable gases。 the UDF is based contains several assumptions: 1. Vapor phase contains a binary ideal gas mixture of air and water vapor 2. The liquid phase consists of only water 3. Local thermodynamic equilibrium exists at the liquid-vapor interface 4. Film condensation only is considered. Dropwise condensation does not take place 5. The thermal resistance of the liquid film is neglected.