Abstract
In this study, the flow boiling heat transfer characteristics of R1234ze(E) and R32 in a horizontal two rectangular multi-port tubes are investigated experimentally. The hydraulic diameters of tested tube are 0.85 and 1.13 mm, respectively. The effect of refrigerants and hydraulic diameters on the heat transfer characteristics are clarified. Heat transfer characteristics in the horizontal multi-port tubes are strongly influenced by forced convective evaporation especially in the region where the liquid film is thinner. The heat transfer coefficient of 0.85mm is higher than 1.13 mm. The heat transfer coefficient of R32 is higher than that of R1234ze(E) at entire the test range.
