Adiabatic capillary tube flows of n-butane and isobutane

This paper presents an experimental study of n-butane (R600) and isobutane (R600a) flows in adiabatic capillary tubes. In total, 48 experimental data points were gathered spanning the typical conditions of household refrigerators, with capillary inner diameters ranging from 0.53 to 0.79 mm, tube lengths ranging from 2.5 to 3.5 m, inlet pressure ranging from 2.83 to 6.05 bar, exit pressure ranging from 0.3 to 0.9 bar, inlet subcooling ranging from 4.7 to 15.2 degrees C, and mass flow rates ranging from 0.53 to 2.95 kg h(-1). In addition, the accuracy of pi-type correlations priorly developed for R600a flows was verified when used with R600 to predict the refrigerant mass flow rate. Also, it was found the mass flow rate predictions of the algebraic model developed by Hermes et al. (2010) for R600a agreed well with the R600 experimental data, with more than 90 % of data points within +/- 10 % error bands.