Boiling heat transfer in a micro tube - 2nd report: heat transfer coefficient and pressure drop

摘要

The authors had previously reported the characteristics of two-phase flow pattern of refrigerant R134a in horizontal micro tubes. In that report, the flow pattern in micro tubes is different from that of larger-diameter tubes. In this paper, the forced convective-boiling heat transfer coefficient and pressure drop in micro tubes (Φl.0 and 2.0mm) were measured. The parameters considered in this study are mass velocity: 100 to 400 kg/(m{sup}2s), heat flux: 5 to 50k/(m{sup}2s), quality: 0.1 to 0.8. The results indicate that heat transfer is dominated by nucleate pool boiling heat transfer.