DIFFUSION LAYER THEORY FOR TURBULENT VAPOR CONDENSATION WITH NONCONDENSABLE GASES

In turbulent condensation with noncondensable gas, a thin noncondensab le layer accumulates and generates a diffusional resistance to condens ation and sensible heat transfer. By expressing the driving potential for mass transfer as a difference in saturation temperatures and using appropriate thermodynamic relationships, here an effective ''condensa tion'' thermal conductivity is derived. With this formulation, experim ental results for vertical tubes and plates demonstrate that condensat ion obeys the heat and mass transfer analogy, when condensation and se nsible heat transfer are considered simultaneously. The sum of the con densation and sensible heat transfer coefficients becomes infinite at small gas concentrations, and approaches the sensible heat transfer co efficient at large concentrations. The ''condensation '' thermal condu ctivity is easily applied to engineering analysis, and the theory furt her demonstrates that condensation on large vertical surfaces is indep endent of the surface height.