Theoretical calculation on forced convective condensation heat transfer coefficient of nonazeotropic mixtures inside tube

A theoretical approach to forced convective condensation heat transfer coefficient of nonazeotropic mixtures inside smooth tubes was developed. Calculations were performed for R32/R134a mixtures with the R32 mass fraction ranged from 0 to 60.1%. The results reveals that there is a reduction of heat transfer coefficient for a nonazeotropic mixture compared with that of a single component substance with the same thermophysical properties. The reduction of the heat transfer coefficient depends not only on the mass fraction of the mixture, but also on the vapor quality of the fluid. Besides, minimum heat transfer coefficients were observed at mass fractions ranging from 10% to 30% for R32/R234a mixtures.