2. The Turbulence Damping Effect on the Slug Flow Modeling

The slug flow is one of the most complex flow patterns due to the unstable behavior of phase distribution. This pattern occurs in a wide range of flow rates and therefore is observed in different industrial processes. The prediction and understanding of the hydrodynamic parameters of this flow regime have a significant engineering value. In this context, Computational Fluid Dynamics (CFD) has been shown to be an efficient tool for the prediction of this type of flow. However, to ensure the accuracy of the numerical solution, adequate modeling of interfacial properties transfer is necessary. One of the most important interface transfer phenomena is momentum transfer between phases. Therefore, it is necessary to use a robust approach to model the gas–liquid interface region. The aim of this study is to evaluate the effect of adding the damping of turbulent diffusion at the interface on flow modeling. For this, different cases of simulations were elaborated for a pipe with 2 m in length and 26 mm inner diameter. In all the cases, the multiphase approach used was the Volume of Fluid (VOF) with the Geo-Reconstruct scheme. The interface between the fluids was modeled with constant surface tension equal to 0.0728 N/m. The discontinuities present at the interface were treated in a “continuous surface stress” (CSS) manner. The turbulence was modeled using kω-SST with and without turbulence damping. The independence of the numerical solution in relation to the grid was evaluated by the Grid Convergence Index (GCI) method in which four levels of grid were used. Preliminary results showed that, in the cases with turbulence damping, a better representation of the flow pattern morphology was obtained. Regarding the quantitative parameters, the prominent frequency of the Power Spectral Density (PSD) of the pressure signal was under-predicted when the turbulence damping was not used.