4279 -- Multiphase Flow of Refrigerant 410A Through Short Tube Orifices

The (near) azeotropic refrigerant R-410A, a mixture of 50% R-32 and 50% R-125 by mass, was tested in critical flow through short tube orifices of length 12.7 mm (0.5 in.), 19.05 mm (0.75 in.), and 25.4 mm (1.0 in.) with diameters ranging from 1.09 mm (0.0432 in.) to 1.94 mm (0.0763 in.). Simulated condensing temperatures ranged from 26.7°C (80°F) to 51.7°C (125°F) with evaporating conditions of -1.11°C (30°F) to 10.0°C (50°F). Upstream pressures corresponding to the various condensing temperatures ranged from a peak value of 3176 kPa (461 psia) to 2136 kPa (310 psia). Downstream pressure, upstream pressure, upstream subcooling/ quality, short tube diameter, and short tube length were studied to determine their effects on refrigerant mass flow rate. Comparisons were made with R-22 for comparable evaporating and condensing conditions.

Units: Dual