垂直二重円管二相熱サイフォンの限界熱流束 : 限界熱流束の改善について

抄録

An experimental study has been made to elucidate the characteristics of critical heat flux (CHF) in a concentric tube thermosyphon. The experiment has been done by using saturated water, ethanol and R 113 over the experimental range of configuration : inner diameter of heated tube D_i=9-17 mm, outer diameter of inner tube d_o=3-15 mm and heated tube length L=100-1 000 mm. The experiment shows that the CHF is enhanced with an increase in the inner tube diameter, and then the CHF is reversely decreased beyond a certain diameter of inner tube for each heated tube diameter. The maximum CHF is about two or eight times as large as that without inner tube depending on the condition of the inner and outer tubes. For larger inner tube, the characteristic of CHF is similar to that of natural convective boiling in a vertical annular tube.