Dual model of bubble growth in vertical rectangular narrow channel

The mechanism of bubble growth has been of particular interest for decades due to its significant contribution to understanding boiling heat transfer. In present work, a visualization experiment was carried out to analyze the bubble growth in a vertical rectangular narrow channel by using water as working fluid under 1 and 3 bar system pressure. The bubble growth in various experimental conditions was obtained by analyzing the recorded pictures. Results show that bubble growth and bubble size are significantly affected by mass flux, heat flux and system pressure, and also by the nucleation site density. To obtain a well prediction for bubble growth, a dual model is proposed in this paper. This model is comprised of a linear model for the inertia controlled stage of bubble growth and a power law model for the heat diffusion controlled stage of bubble growth, and the prediction of the dual model agrees well with the experimental result with an error less than ± 15%.