Effect of nucleation bubble departure diameter and frequency on modeling subcooled flow boiling in an annular flow

The accuracy of CFD modeling of two phase flows in tube-bundles is highly depended on the correlations for predicting the nucleation site density, and bubble departure size and frequency. Both theoretical predictions and experimental correlations are available for these nucleation parameters. However, these models are only valid for a narrow range of operating conditions and working fluids. This study examines the significance and sensitivity of the bubble departure diameter and frequency in the boiling mechanism and its eventual effect on the final conditions of the flow in an annular tube with subcooled flow representing fuel channels of a nuclear reactor.