TY - JOUR
T1 - Comparison of heat transfer coefficient during evaporation of natural refrigerants and R-1234yf in horizontal small tube
AU - Choi, Kwang Il
AU - Oh, Jong Taek
AU - Saito, Kiyoshi
AU - Jeong, Jong Soo
N1 - Funding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education ( NRF-2013R1A1A2013476 ).
PY - 2014/5
Y1 - 2014/5
N2 - An experimental data comparison of evaporation heat transfer coefficient of R-744(CO2), R-717(NH3), R-290(C3H8) and R-1234yf in horizontal small tubes was conducted under some various flow conditions. The experimental data were obtained over a heat flux range of 5-60 kW m-2, mass fluxes from 50 to 600 kg m-2 s-1, saturation temperatures from 0 to 10 °C, and quality up to 1.0. The test section made of stainless steel tubes with inner diameters of 1.5 mm and 3.0 mm, and a length of 1000 and 2000 mm, respectively, was heated uniformly by applying an electric power to the tubes directly. Effects of mass flux, heat flux, saturation temperature and inner tube diameter on heat transfer coefficient are reported in the present study. Among the present working refrigerants, R-744 has a highest heat transfer coefficient. Laminar flow was observed in the evaporative small tubes and considered in the modification of evaporation heat transfer coefficient correlations.
AB - An experimental data comparison of evaporation heat transfer coefficient of R-744(CO2), R-717(NH3), R-290(C3H8) and R-1234yf in horizontal small tubes was conducted under some various flow conditions. The experimental data were obtained over a heat flux range of 5-60 kW m-2, mass fluxes from 50 to 600 kg m-2 s-1, saturation temperatures from 0 to 10 °C, and quality up to 1.0. The test section made of stainless steel tubes with inner diameters of 1.5 mm and 3.0 mm, and a length of 1000 and 2000 mm, respectively, was heated uniformly by applying an electric power to the tubes directly. Effects of mass flux, heat flux, saturation temperature and inner tube diameter on heat transfer coefficient are reported in the present study. Among the present working refrigerants, R-744 has a highest heat transfer coefficient. Laminar flow was observed in the evaporative small tubes and considered in the modification of evaporation heat transfer coefficient correlations.
KW - Correlation
KW - Heat transfer coefficient
KW - Horizontal small tube
KW - Natural refrigerants (R-744, R-717, R-290)
KW - R-1234yf
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U2 - 10.1016/j.ijrefrig.2013.06.017
DO - 10.1016/j.ijrefrig.2013.06.017
M3 - Article
AN - SCOPUS:84901934051
SN - 0140-7007
VL - 41
SP - 210
EP - 218
JO - International Journal of Refrigeration
JF - International Journal of Refrigeration
ER -