Bubble Lift-Off Size in Forced Convection Subcooled Boiling

Forced convection subcooled boiling experiments were conducted in a BWR-scaled vertical upward annular channel. Water was used as the testing fluid, and the tests were performed at atmospheric pressure. A high-speed digital video camera was applied to capture the dynamics of the bubble nucleation process. Bubble lift-off diameters were obtained from the images for a total of 91 test conditions. A force balance analysis of a growing bubble was carried out. A constitutive relation for bubble lift-off size was obtained by correlating current water data and R113 data from literature. The proposed constitutive relation and experimental data agree well with each other.