Influence of reduced gravity on liquid helium pool boiling heat transfer

Through a series of experimental sessions, we have characterized pool boiling heat transfer in liquid helium (LHe) around saturation (4.2 K) under reduced gravity conditions ranging from 0.02g to 1g using magnetic forces. The magnetic forces were generated using a 30 T resistive magnet. First, the experimental results confirm and strengthen previous measurements regarding the critical heat flux dependency with respect to reduced gravity. Secondly and more importantly, they provide Nukiyama’s curves for liquid helium at 4.2 K and 1 bar at various reduced gravity levels ( ≈ 0.02g, ≈ 0.25g, ≈ 0.5g, 1g). Measurements of both nucleate and film boiling regimes are studied and compared with considerations of their theoretically predicted gravity-dependent evolution. The measurements do not show significant degradation of the heat transfer coefficient under reduced gravity only the critical heat flux seems to be drastically impacted by the gravity level.