Simulation of two-phase refrigerant separation in horizontal T-junction

This paper describes a 3D numerical simulation to model the two-phase separation of refrigerants in a horizontal run-type T-junction. The computations are based on the Eulerian method with the k-ε turbulence model. Compared with data from existing experiments and phenomenological models, the average deviation of the established model is less than 5% when the liquid mass flow rate ratio is in the range 0.2-0.6. The effect of multiple parameters on phase separation is investigated using the validated model. The results show that the inlet qualities (0.3-0.7), saturation temperatures (279.15-284.15 K), and working fluids of R22 and R134a have little influence on the phase separation at the T-junction, whereas the gas mass flow rate ratio increases with the increase in inlet mass flux (100-500 kg m−2 s−1). Furthermore, it is found that two symmetric recirculation regions occur directly after the junction at the entrance to the branch.