Flow of partially condensed R-134a vapour through an adiabatic capillary tube

This paper presents an experimental study of an adiabatic flow of R-134a through a capillary tube. The paper discusses the details of experimental facility for testing a capillary tube with sub-cooled and two phase inlet conditions of R-134a. The effect of diameter, capillary length, inlet refrigerant quality and inlet pressure on mass flow rate were investigated. The experiments for testing the capillary tubes were proceeded by an integrity test. The vapour quality varied from 0.05 to 0.25. All the experiments were done by varying the pressure from 655 to 724 kPa. The effect of two phase inlet conditions on mass flow rate of R-134a through an adiabatic capillary tube is observed. A correlation to predict the mass flow rate of refrigerant flowing through an adiabatic capillary tube is proposed for two phase inlet conditions. The proposed correlation predicts the measured data with an error band of ±25%.