Heat Transfer to Helium II for Big Differences of Temperature between Heated Wall and Superfluid Helium Bath
The heat transfer coefficient in helium II has only been investigated for small differences in temperature. For big AT we could observe a new phenomenon: a steady gaseous helium film (up to a few tenths of a millimeter) isolates the heated surface from the superfluid helium bath without any layer of nuclear boiling. The experiments were carried out with a heated platinum wire (up to glowing temperatures) of 15 μ in diameter at 1.4°K. The heat transfer coefficient was measured for ΔT up to 600°K and simultaneously the thickness of the gaseous helium film was determined by photographs, using an opposite-light technique.