Theoretical Research on Critical Heat Flux of Vertical Tube Based on Bubbly Crowding Model  

To study the single pipe CHF phenomenon of the bubble crowding, the CHF calculation model was developed based on the near wall bubble crowding mechanism model. The CHF was obtained by solving the mass, momentum and energy equation together with bubbly detaching model and critical void fraction model in the near wall. The results calculated by the model were compared with the experimental data and a good agreement was achieved. Based on the CHF calculation model, the CHF varing with the inlet enthalpy difference, mass flow rate, diameter and length was studied, which could be used to predicting the bubbly crowding CHF.