| Title |
An Experimental Study on the Evaporative Heat Transfer Characteristics of CO2/Propane Mixtures Flowing Upward in Vertical Smooth and Micro-fin Tubes with an Outer Diameter of 5mm |
| Authors |
조진민(Jin Min Cho) ; 김민수(Min Soo Kim) |
| Keywords |
증발 ; 이산화탄소/프로판 ; 수직평활관 ; 수직 마이크로핀관 ; 열전달계수 ; 압력강하 Evaporation ; CO2/propane ; Vertical Smooth Tube ; Vertical Micro-fin Tube ; Heat Transfer Coefficient ; Pressure Drop ; |
| Abstract |
Refrigerant mixtures provide an opportunity to adjust their properties to fit design criteria and a possibility to create new blends that can improve heat transfer characteristics. Therefore, mixture of CO2 and propane is chosen which may be a promising refrigerant and has good environmental compatibility. This paper presents measured heat transfer coefficient data during evaporation process of CO2/propane mixtures flowing upward in vertical smooth and micro-fin tubes. Smooth and micro-fin tubes with outer diameters of 5mm and length of 1.44m were selected as test tubes. The tests were conducted at mass fluxes of 212 to 656kg/㎡s, inlet temperatures of -10 to 30℃, heat fluxes of 15 to 60kW/㎡ and for several compositions (75/25, 50/50, 25/75wt%). Among CO2/propane refrigerant mixtures, the heat transfer characteristics are much better than that of any compositions when the composition is 75/25 (wt%). |