HEAT-TRANSPORT IN HE-II CHANNEL WITH PHASE-TRANSITION

Experimental and numerical investigations have been carried out on the heat transport characteristics in a channel where atmospherically pre ssurized He II coexists with He I. The channel has a rectangular cross -section and both ends are open to the bath. One of the side walls of the channel is heated uniformly. The channel is placed vertically or h orizontally in the bath. The experimental results are analysed by two- dimensional time-dependent numerical calculations. An explicit finite element scheme is applied to the two-fluid equations which include the Gorter-Mellink mutual friction term. It is found that the applied hea t is transported by one-dimensional internal convection through the ch annel filled with single phase He II. Once He I is generated in the ch annel, however, two-dimensional flow occurs due to natural convection and this influences the transport of heat.