Thermal characteristics of double-tube two-phase thermosiphon

In a closed-thermosiphon, countercurrent flow, there results a thermal limit due to the occurrence of flooding. In this paper, a double-tube closed thermosiphon, that is, a conventional single-tube thermosiphon with an inner tube inserted in which condensate liquid is designed to flow down is proposed. Visual observation experiments of the inside flow are carried out with a single-tube glass thermosiphon. It is observed that, with an inner tube properly designed, inner natural circulation is realized and flooding is avoided. Experiments with a stainless double-tube closed thermosiphon reveal that the heating limit for this thermosiphon is greatly increased. General characteristics of this thermosiphon are presented.