DA-00-04-3 -- Critical Flow of Refrigerants Through Adiabatic Capillary Tubes: Experimental Study of Zeotropic Mixtures R-407c and R-404a PDF

This paper investigates the flow of zeotropic mixtures of refrigerants through adiabatic capillary tubes. First, an extensive literature review related to the experimental study of these expansion devices was carried out. The results of this literature search showed a lack of experimental data for two fluids, R-407c and R-404a, in spite of the important role that these fluids now play as substitutes for R-22 and R-502 and the practical use of adiabatic capillary tubes in refrigeration systems. Extensive experimental data are presented for five different geometric configurations covering two inner diameters, 1.06 mm and 1.85 mm (0.0417 in. and 0.0728 in.), and three lengths, 1.05 m, 1.30 m, and 1.60 m (41.33 in., 51.18 in., and 62.99 in.). The flow rate covers a range of 10 kg/h to 112 kg/h (22 lb/h to 246.4 lb/h). The operating conditions were 220 psig to 280 psig (1618 kPa to 2031 kPa) of condensing pressure and 5°C to 30°C (9°F to 54°F) of subcooling. These results are presented in both graphical and tabulated forms and are intended to be a contribution to the development of environmentally benign refrigeration systems.

Units: Dual