Effects of header configurations and perforated insertion tubes on gas–liquid two-phase flow distribution

Uniform gas-liquid distribution among parallel micro-channel tubes is essential for achieving high thermal performance in heat exchangers. The effects of different header configurations and perforated insertion tubes on two-phase flow distribution were systematically investigated in this paper. Thirty vertical upward branch channels are used to simulate the micro-channel tube bundles. Four typical header configurations, including 0%, 50% branch intrusion and their combinations, are designed and the liquid and gas distribution performance is evaluated. The experiments are conducted under mass fluxes of 50–150 kg/(m 2 ·s) and gas qualities of 0.01–0.05. The results indicate that in the absence of perforated insertion tubes, Header Configuration 2 exhibits the best liquid distribution uniformity, while Header Configuration 4 shows the best gas distribution uniformity. In Header Configuration 2, Perforated Insertion Tube 6 improves liquid and gas uniformity by 54.5% and 85.5% on average, respectively. The pressure drop is influenced much more significantly by the mass flux, gas quality, and the diameter of the perforated insertion tube than by the header configuration. For Header Configurations 1–4, the pressure drop with the 4 mm inner diameter perforated insertion tube is 5.9%, 6.7%, 11.0%, and 6.0% higher, respectively, compared to that with the 8 mm tube.