An experimental study of heat transfer characteristics of a two-phase nitrogen thermosyphon over a large dynamic range operation

Heat transport characteristics of a cryogenic two-phase nitrogen thermosyphon have been experimentally investigated in this study. The thermal resistance and the maximum heat transfer rate were mainly investigated over a wide dynamic range from near the triple point to the critical point. The experimental data suggests that the nominal thermal resistance does not have pressure dependence in the high pressure and high temperature region. The present experimental result is well explained by the theoretical prediction. From the experimental result of the operating limit of the thermosyphon, it is found that the maximum heat transfer rate is governed by the interaction between the vapor flow and the returning liquid film flow along the wall in the evaporator section, even near the critical point.