1993 年 28 巻 9 号 p. 540-544
Heat transport characteristics in a channel containing He II have been experimentally investigated. Three model channels are examined. The geometries of model channels are 170mm in length and 7.0mm wide with gaps of 0.5, 1.0 and 1.5mm. Both ends of the channel are open to He II at the atmospheric pressure. One of the side wall of the channel is heated uniformly. When heat flux less than the λ transition heat flux qλ is applied, the center portion of the channel has the highest temperature. In this case, internal convection of He II dominates the heat transfer mechanism. When heat flux lager than qλ is applied in the channel placed vertically, He II at the center of the channel changes to He I firstly, and then the He I flows upwards through the channel with further increase of the heat. In consequence, the top of the channel has the highest temperature in the steady state. On the other hand, in the case of the horizontally placed channel, the highest temperature is kept at the center of the channel even after the λ transition occurs.