Modelling horizontal two-phase flows using generalized models

Stratified two-phase flows are relevant in many industrial applications, e.g. pipelines, horizontal heat exchangers and storage tanks. The numerical simulation of free surface flows can be performed using phase-averaged multi-fluid models, like the homogeneous and the two-fluid approaches, or non-phase-averaged variants. The approach shown in this paper within the two-fluid framework is the Algebraic Interfacial Area Density (AIAD) model. It allows the macroscopic blending between different models for the calculation of the interfacial area density and improved models for momentum transfer in dependence on local morphology. A further step of improvement of modelling the turbulence is the consideration of sub-grid wave turbulence (SWT) that means waves created by Kelvin-Helmholtz instabilities that are smaller than the grid size. A first CFD validation of the approach is performed by means of experimental data of horizontal adiabatic stratified flow from the HAWAC and WENKA facilities. More verification and validation of the approach is necessary – more CFD grade experimental data are required for the validation.