Pool boiling heat transfer on small heaters: effect of gravity and subcooling

Measurements of space and time resolved subcooled pool boiling of FC-72 in low, earth, and high gravity environments were made using a microscale heater array. Data from each heater in the array were synchronized with high-speed digital video. The boiling behavior was dominated by the formation of a large primary bubble on the surface which acted as a “sink” for many smaller bubbles surrounding it. Dryout of the heater occurred under the primary bubble. For a given superheat, this primary bubble was observed to increase in size with bulk fluid temperature. Boiling curves at various subcoolings and gravity levels are presented.