Aircraft Experiments of Microgravity Pool Boiling : Evaluation of the Residual Acceleration

Abstract

The papaer describes analyses of the data obtained in our aircraft pool-boiling experiments performed at Bretigny, France in December 1989, placing the focus on possible effects of residual acceleration on the vapor-bubble behabior as well as the heat transfer characteristics. In the experiments, the appratus including a boiling call filled with subcooled n-pentane was fixed onto the cabin floor of the aircraft during some parabolic flights, but it was freely floated in the cabin during other parabolic flights. Thus, the experiments provided us with two classes of data each reflecting one of the two oscillatory acceleration levels different from each other by more than one order of magnitude. Analyses of the whole data revealed a significant difference between the two classes in the frequency of bubble departure from the heater surface, but no detectable difference in the heat transfer coefficient averaged over the heater surface.