Effect of superheating on heat transfer from a good thermal conductor in a two-dimensional channel to He II below the λ-point pressure

Heat transfer characteristics in He II have been investigated in relation to superheating. When a good thermal conductor in a narrow two-dimensional channel is heated above the critical heat flux of the λ-transition, superheated He I nucleates in the hottest area of the conductor covered with superheated He II. The spread of superheated He I, which has a low thermal conductivity, forms an intermediate state in which superheated He I coexists with superheated He II. Superheated He I together with superheated He II is apparently stabilized since part of the heat cut off by superheated He I tends to flow in the conductor. Higher heat input turns the intermediate state into a mixed state where superheating and boiling alternate irregularly.