An assessment of Average Bubble Number Density model for bubbly flows

Gas-liquid bubbly flows with wide range of bubble sizes are commonly encountered in many industrial applications. Based on our previous study, a generalized Average Bubble Number Density (ABND) model has been developed to model the dynamical changes of bubble size due to bubble coalescence and breakage mechanism. With the aim to asses the model performance, numerical studies have been performed to validate the model predictions against experimental data. Three experimental data [7,10,12] exhibiting totally different bubble size evolution trends were strategically selected for the present validation study. Numerical predictions were validated against measured results under three different experimental conditions. In general, predictions of the ABND model yield good agreement with experimental data. The encouraging results demonstrated the capability of the ABND model in capturing the changes of bubbles size due to bubble interactions and the transition from "wall peak" to "core peak" gas volume fraction profiles under various flow conditions. Merits and drawbacks of the ABND model for industrial application are also discussed.