| Title |
External Condensation Heat Transfer Coefficients of HFC32/HFC152a Mixtures on Enhanced Tubes |
| Authors |
이요한(Yohan Lee) ; 강동규(Donggyu Kang) ; 김현주(Hyeon-Ju Kim) ; 이호생(Ho-Saeng Lee) ; 정동수(Dongsoo Jung) |
| DOI |
http://dx.doi.org/10.6110/KJACR.2014.26.7.315 |
| Keywords |
응축열전달 ; 혼합냉매 ; 열전달계수 ; 비공비 혼합냉매 ; 26 fpi 낮은 핀 관 ; Turbo-C 촉진관 Condensation heat transfer ; Refrigerant mixture ; Heat transfer coefficient ; Non-azeotropic mixture ; 26 fpi Low-fin tube ; Turbo-C enhanced tube |
| Abstract |
In this study, external condensation heat transfer coefficients (HTCs) of two non-azeotropic refrigerant mixtures of HFC32/HFC152a at various compositions were measured on both 26 fpi low-fin and Turbo-C enhanced tubes, of 19.0 mm outside diameter. All data were taken at the vapor temperature of 39℃, with a wall subcooling of 3∼8 K. Test results showed that the HTCs of the tested mixtures on the enhanced tubes were much lower than the ideal values calculated by mass fraction weighting of the pure component HTCs. Also, the reduction of HTCs due to the diffusion vapor film was much larger than that of a plain tube. Unlike HTCs of pure fluids, HTCs of the mixtures measured on enhanced tubes increased, as the wall subcooling increased, which was due to the sudden break-up of the vapor diffusion film with an increase in wall subcooling. Finally, the heat transfer enhancement ratios for mixtures were found to be much lower, than those of pure fluids. |