Modelling of Polydispersed Flows using Two Population Balance Approaches

Polydispersed bubbly flows with wide range of bubble size are commonly encountered in many industrial fields. The use of population balance models coupled with the two-fluid model presents the most viable way of handling such complex flow structures. The main focus of this paper is to access the capabilities of two population balance models namely Average Bubble Number Density (ABND) and Inhomogeneous MUlti-Size-Group (MUSIG) model; in resolving the dynamical changes of void fraction and bubble size distribution under polydispersed flow conditions. Numerical predictions are validated against two polydispersed flow measurements. Special attentions are directed towards the performance of the two models in capturing the behavioral transition of "wall peak" to "core peak" void fraction profile. Applicability and drawbacks of the two population balance models for industrial applications are also discussed.