抄録
Condensation heat transfer of a nonazeotropic binary R113-R114 vapor mixture in a vertical tube is investigated experimentally and theoretically, for cases of both constant and varying wall temperature along a flow direction. Experimental results show that a minimum temperature difference is required for complete condensation at an outlet of the condenser tube. This temperature difference and the heat transfer coefficients can be accurately predicted by a theory which assumes a well-mixed condition in the condensate, that is, a uniform concentration profile in the condensed liquid. When the fin height is 0.2 mm, augmentation of heat transfer by an inner finned surface occurrs in the liquid film but not in a vapor phase. For both cases of the constant and varying wall temperature, the heat transfer coefficients correlate well when an averaged temperature difference between the wall and the bulk flow is used as a characteristic temperature difference.
