AN EXPERIMENTAL-STUDY OF FORCED-CONVECTION BOILING IN MICROGRAVITY

Pool and forced-convection boiling of FC-72 was conducted in earth gra vity and microgravity. A thin gold-film semi-transparent heater was us ed to provide both uniform heat flux and measurement of the heater sur face mean temperature simultaneously. Boiling curves of FC-72 at diffe rent flow rates were measured in the experiment. Flow boiling map and average bubble size vs flow rate in microgravity were obtained using p hotographic technique. II was observed that the forced flow would decr ease the average bubble size and keep boiling in the nucleate boiling regime in microgravity. The influence of forced flow on heater surface superheat and heat transfer coefficient in microgravity were also stu died in the experiment. With the increase of flow rate, it was found t hat the average superheat of the heater surface would decrease and the heat transfer coefficient would increase. (C) 1998 Elsevier Science L td. All rights reserved.