Condensation heat transfer coefficients of flammable refrigerants |
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Authors: | Dongsoo Jung Soonam Chae Dongsoo Bae Sukjae Oho |
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Affiliation: | a Department of Mechanical Engineering, Inha University, Incheon 402-751, South Korea;b TechnoChem Co., Ltd., Pyungtaek-Si, Kyunggi-Do, South Korea |
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Abstract: | In this study, external condensation heat transfer coefficients (HTCs) of six flammable refrigerants of propylene (R1270), propane (R290), isobutane (R600a), butane (R600), dimethylether (RE170), and HFC32 were measured at the vapor temperature of 39 °C on a plain tube of 19.0 mm outside diameter with a wall subcooling of 3–8 °C under a heat flux of 7–23 kW m−2. Test results showed a typical trend that external condensation HTCs decrease with the wall subcooling. No unusual behavior or phenomenon was observed for these flammable refrigerants during experiments. HFC32 and DME showed 28–44% higher HTCs than those of HCFC22 due to their excellent thermophysical properties. Propylene and butane showed the similar HTCs as those of HCFC22 while propane and isobutane showed 9% lower HTCs than those of HCFC22. Finally, a general correlation was made by modifying Nusselt's equation based upon the measured data of eleven fluids of various vapor pressures including halogenated refrigerants. The general equation showed an excellent agreement with all data exhibiting a deviation of less than 3%. |
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Keywords: | Condensation Horizontal tube Heat transfer coefficient Mass transfer condensation Propylene Propane Butane Isobutane R32Condensation Tube horizontal Coefficient de transfert de chaleur Coefficient de transfert de masse Propylè ne Propane Butane Isobutane R32 |
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