Bubble-induced Turbulence: Comparison of CFD Models

Modeling of bubble-induced turbulence in dispersed gas-liquid multiphase flow is an important but still unresolved issue. Aside from its intrinsic interest, turbulence in this type of flow has a strong impact on other important processes like turbulent dispersion of the bubbles and bubble-coalescence and -breakup and thus is a central part of the overall model. A common approach is to add source terms to the single phase two-equation turbulence models, but no agreement on the precise form of these terms has been reached yet. We here report a comparison of different models of this type, some of which have been used previously and some of which are new. To qualify the validity of the different models a set of reference data has been selected from the literature. Conclusions towards best practice guidelines for modeling bubbly turbulence are drawn and needs for further research identified.