Flow Boiling Heat Transfer of Refrigerant Mixtures in Horizontal Minichannels

Experimental studies of boiling heat transfer with refrigerants R-410A and R-407C in minichannels are presented. This thesis is focused on pressure drop and boiling heat transfer coefficient of the refrigerants inside a horizontal smooth minichannel in order to develop pressure drop and heat transfer coefficient correlations for the refrigerant mixtures. To evaluate the diameter size effect on pressure drop and heat transfer characteristics, minichannels wit inner tube diameters of 3.0mm and 1.5mm and with lengths of 3000mm and 1500mm respectively are used. The pressure drop increased with mass flux and heat flux increase for both inner tube diameters and for both the refrigerants. The pressure drop of R-407C is higher than that of R-410A, but the heat transfer coefficient of R-410A is higher than of R-407C at the low quality region. The heat transfer coefficient in the tube with an inner diameter of 1.5mm is higherthan that of 3.0mm diameter tube at the low quality region. The comparison of the pressure drop between of this study and o