Abstract
Heat transfer from horizontal copper surface to liquid helium at near the lambda line is measured in the range of saturated pressure to 8.0kgf/cm2. The heat transfer surface is 2.0cm in diameter and heated electrically. In nucleate boiling of He I heat transfer at near the lambda point the temperature of the heat transfer surface increases rapidly in step heat input and then decreases very slowly toward steady state. In natural convection regime, large and slow fluctuations in surface temperature observed.
In pressurized He II, below the critical pressure, heat transfer data obtained at close lambda temperature show the behavior of nucleate boiling of subcooled He I. Above the critical pressure He II heat transfer data near lambda temperature show transition to boiling curve different from that of supercritical He I heat transfer.
