Experimental study on the distribution of constituents of binary zeotropic mixtures in vertical impacting T-junction

In this paper, the distributions of constituents of binary zeotropic mixtures, R134a/R245fa, at vertical impacting T-junctions were investigated experimentally. An online measurement method with a Coriolis mass flow meter was used for identifying liquid-phase mixture composition. The effects of inlet conditions, such as vapor quality, mass flux and refrigerant composition, as well as outlet conditions, such as the outlet to inlet flow ratio and outlet tube diameter, on the constituent separation performance were investigated and compared based on a wide range of test conditions. The relationship between constituent distribution and phase distribution was also discussed based on the degree of deviation from the ideal separation process. During the experiments, R134a/R245fa zeotropic mixture with an R134a mass fraction of 0.3215 shows the largest variation range of R134a mass fraction from 0.2717 to 0.3492 at the T-junction outlet. In the T-junction with an outlet-inlet tube diameter ratio of 0.457, the mixture having an R134a mass fraction of 0.7075 shows the best constituent separation performance under test condition of 0.49 vapor quality and 200 kg m−2 s−1 mass flux with an outlet-inlet mass flow ratio of 0.5. It was found that the pressure across the T-junction plays an important role on the mal-distribution of constituents. Therefore, increase of the mass fraction of R245fa would lead to the increase of pressure drop, so deteriorating the constituent separation performance.