Numerical simulation of bubble dynamics in subcooled flow boiling in a channel

In this article, we report bubble dynamics in a subcooled flow boiling in a vertical boiling channel based on numerical simulation using four-equation drift flux model (DFM4). The focus of this work is to validate the bubble phenomena computed by DFM4 in high inlet subcooling, low heat fluxes and low flow rates. The computed bubble parameters such as bubble growth time t(g), bubble waiting time t(w), bubble departure diameter D-d based on the available correlations were compared with the experimental results obtained from our boiling loop. We also propose an analytical solution for t(g) and D-d from the asymptotic growth kinetics and the force balance at the time of bubble departure. We have explained some important insights of the axial variation of bubble phenomena under varying heat flux. Unal correlation for bubble departure works extremely well to a highly subcooled boiling in low heat fluxes and low flows.