Bubble Lift-off Size in Forced Convective Subcooled Boiling Flow

Forced convective subcooled boiling flow 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 performed to predict the bubble lift-off size. The dimensionless form of the bubble lift-off diameter was formulated to be a function of Jacob number and Prandtl number. The proposed model agreed well with the experimental data within the averaged relative deviation of ±35.2 %

Photographic Study of Bubble Behaviors in Forced Convection Subcooled Boiling

Forced convection subcooled water boiling experiments were conducted in a vertical annular channel. A high-speed digital video camera was applied to record the dynamics of the subcooled boiling process. The flow visualization results show that the bubble departure frequency generally increases as the heat flux increases. For some cases, the departure frequency may reach a limit around 1000 bubbles/second. In addition, bubble lift-off diameter, bubble growth rate and bubble velocity after bubble lift-off were determined by analyzing the images. The experimental data obtained from this study can be used in modeling the bubble departure frequency, bubble lift-off diameter, and bubble dynamics in forced convection subcooled boiling

Photographic Study of Bubble Behaviors in Subcooled Boiling

Forced convection subcooled water boiling experiments are conducted on a vertical-upward annular channel. A high-speed digital video camera (5,000 frames/second) is used to record the dynamics of the subcooled ebullition process. The flow visualization experiments show that generally the bubble departure frequency increases as the heat flux increases. For some cases, the frequency may reach a limit around 1000 bubbles/second. The average bubble lift-off diameter becomes smaller as the heat flux increases. In addition, the bubble diameter growth and bubble velocity after bubble lift-off is determined by analyzing the image. The experimental data obtained from this study can be used in modeling of the bubble departure frequency, bubble lift-off diameter, and bubble dynamics in subcooled boiling

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