Numerical simulation of subcooled boiling considering bubble sliding behavior in conventional channels

Abstract

Subcooled boiling has a strong heat transfer capacity, and its heat transfer effect is closely related to the dynamic behavior of bubbles. Many researchers have discovered the bubble sliding behavior in subcooled boiling, which disrupts the thermal boundary layer and thus enhances the heat transfer capacity. This phenomenon occurs not only in narrow channels, but also in conventional channels. In this paper, the wall boiling model including the effect of the sliding bubbles and the nucleation sites density model with a wider application range. The bubble diameter is calculated from the force balance model and coupled into the wall boiling model. On the basis of verifying the accuracy of the model, the variation trend of bubble diameter, nucleation sites density and the relative contribution of each part of wall heat flux along the heating channel and the influence of different working conditions are analyzed. Under different working conditions, the calculated results are in good agreement with most of the experimental data, the error of 90% of the void fraction data is within 25%. In addition, the numerical results show that the relative contribution of bubble sliding quenching heat flux can up to 65%, so the effect of sliding bubbles on the relative contribution of each part of wall heat flux cannot be ignored. Different working conditions indirectly affect the heat flux of each part through the nucleation sites density and the diameter of the bubble.