Aircraft Experiments on Microgravity Pool Boiling. Vapor-Liquid Behavior and Heat Transfer Characteristics in Boiling of n-Pentane, CFC-113 and Water.

Abstract

Boiling of n-pentane, CFC-113 and water under microgravity were studied, utilizing parabolic flight maneuvers with a Caravelle aircraft. The experimental apparatus was constructed so as to permit simultaneous video recording of the side view of vapor bubbles, generated on a Joule-heated, transparent indium-oxide film plated on a glass substrate, and the backside view through the substrate. The heat transfer to n-pentane or CFC-113 in the nucleate-boiling regime deteriorated slightly under microgravity, while the critical heat flux was lowered to two-fifths of the corresponding terrestrial value. In contrast, the heat transfer to water significantly deteriorated under microgravity. The difference in the degree of heat transfer deterioration thus observed is presumably ascribed to a considerable difference, between the former two liquids and water, in the bubble behavior in the vicinity of the heater surface, which in turn must depend on the surface tension of each liquid and the wettability of the heater surface with the liquid.