Two-phase refrigerant distribution for a horizontal header/horizontal mini-channel tube configuration

The literature survey revealed that limited prior investigations exist on the two-phase refrigerant distribution for a horizontal header/horizontal mini-channel tube configuration, which is of importance in many heat exchange circumstances including the cooling of an electric vehicle battery. In this study, we investigated R-1234yf distribution into two mini-channel tubes from a header. Especially, the focus was concentrated on the effect of inlet and outlet configuration on the flow distribution. The tests were conducted for the mass flux from 49 to 147 kg/m²s and the inlet quality from 0.2 to 0.8. The effect of the inclination of the heat exchanger was also investigated. The flow distribution was mainly governed by the balance of the relating forces – momentum, centrifugal and gravitational. Thus, poor distribution was obtained at a tilted case, where the momentum and centrifugal forces were assisting. The flow distribution was also highly dependent on the inlet configuration. On the other hand, the effect of outlet configuration was of secondary importance. The parallel inlet induced a significant mal-distribution compared with the normal inlet, especially in the channel away from the inlet, where an early dry out in the channel was observed. A flow distribution correlation was developed, which predicted the data within ± 30%.