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

•Bubble dynamics in subcooled flow boiling in a vertical boiling channel based on numerical simulation using four-equation drift flux model (DFM4)•Validation of the bubble dynamics computed by DFM4 in high inlet subcooling, low heat fluxes and low flow rates with our experimental data•An analytical solution for tg and Dd at the time of bubble departure•Important insights of the axial variation of bubble dynamics under varying heat flux•Unal correlation for bubble departure works extremely well to a highly subcooled boiling in low heat fluxes and low flows 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 tg, bubble waiting time tw, bubble departure diameter Dd based on the available correlations were compared with the experimental results obtained from our boiling loop. We also propose an analytical solution for tg and Dd 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.