Update the MUSIG model in ANSYS CFX for reliable modelling of bubble coalescence and breakup


Update the MUSIG model in ANSYS CFX for reliable modelling of bubble coalescence and breakup

Liao, Y.

The MUSIG (Multiple Size Group) model in the commercial CFD code ANSYS CFX is a population balance approach for describing binary bubble coalescence and breakup events. It is widely used in the simulation of poly-dispersed bubble flows. The purpose of this work is to identify some inconsistencies in the discrete method that applied for the solution of the population balance equation in MUSIG, and propose an improved one for discretising the source and sink terms that result from bubble coalescence and breakup. The new formulation is superior to the existing ones in preserving both mass and number density of bubbles, allowing arbitrary discretisation schemes and free of costly numerical integrations. The numerical results on the evolution of bubble size distributions in bubble flows reveal that the inconsistency in the original MUSIG regarding bubble breakup is non-negligible in both academic and practical cases. The updates presented in this work are necessary and important for calibration of bubble coalescence and breakup models using the MUSIG approach.

Keywords: MUSIG; ANSYS CFX; Coalescence and breakup; Method of classes; Discrete formulation; Population balance equation

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Permalink: https://www.hzdr.de/publications/Publ-29721
Publ.-Id: 29721