Numerical Investigation of Bubble Condensation of Subcooled Boiling in Narrow Rectangular Channels

The bubble condensation mass and energy transfer models for the subcooled boiling bubbles are developed,and the condensation progress for the bubbles is numerically simulated by VOF multiphase model.The simulation results agree well within ± 20% of the experiment results,which can reflect the real changing history of the parameters.Based on the simulation results,the effect of the initial bubble size,sub-cooling degree and system pressure on the bubble condensation behavior is analyzed.The analysis results show that the bubble lifetime in condensation is proportional to the bubble initial size;with the increasing of subcooling degree,the bubble lifetime will significantly reduce;vortex occurs at the region around the bubble,the higher the subcooling degree,the more intensive the vortex;vortex occurs also within the bubble in high subcooling degree boiling flow;and the bubble lifetime will be prolonged at higher system pressures in narrow rectangular channels.