Inhomogeneous MUSIG model – a population balance approach for polydispersed bubbly flows

A generalized inhomogeneous Multiple Size Group (MUSIG) Model based on the Eulerian modeling framework was developed in close cooperation of ANSYS-CFX and Forschungszentrum Dresden-Rossendorf and implemented into CFX-10. Simulating a poly-dispersed gaseous liquid two phase flow along with the mass exchanged between bubble size classes by bubble coalescence and bubble break-up and the momentum exchange of bubble size dependent bubble forces have to be considered. Particularly the lift force has been proved to play an important role establishing a certain flow regime. The paper describes the main concepts of the model approach and presents a model validation case. Further application test cases are presented by Krepper et al. 2007.
The inhomogeneous MUSIG model approach was shown to be able to describe of bubbly flow with higher gas content. Particularly the separation phenomenon of small and large bubbles which was proven to be a key phenomenon for the establishment of the corresponding flow regime is well described. Weaknesses in this approach can be attributed to the characterization of bubble coalescence and bubble break-up, which must be further investigated.