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A critical analysis of drag force modelling for disperse gas-liquid flow in a pipe with an obstacle
Ist Teil von
Chemical engineering science, 2021-12, Vol.246, p.117007, Article 117007
Ort / Verlag
Elsevier Ltd
Erscheinungsjahr
2021
Link zum Volltext
Quelle
ScienceDirect Journals (5 years ago - present)
Beschreibungen/Notizen
•The capabilities of different drag models under high turbulence /vortex flow conditions are shown.•Impacts of turbulence effects on drag modelling are presented.•A hybrid drag model is proposed for high turbulence flow conditions.•Two-phase flow hydrodynamics under complex flow conditions is analyzed.•Gas velocity and void fraction predictions are compared with experimental data.
The accuracy of the modelling of gas–liquid flows depends strongly on a suitable modelling of the interfacial forces. Among these, drag is dominant. Most drag models reported in the literature have been derived and validated only for laminar or low-turbulent flow conditions. In this study, we numerically evaluated several drag models from the literature for high-turbulent gas–liquid flow around an obstacle in a pipe that creates a distinct vortex region. We performed Computational Fluid Dynamics (CFD) simulations and compared the void fraction and gas velocity profiles with experimental data obtained by ultrafast X-ray computed tomography. We found that all models, except Schiller&Naumann and Feng, predicted the void fraction well compared to experimental data upstream of the obstacle, i.e., for a developed two-phase pipe flow with axial symmetry. However, the void fraction downstream is greatly overestimated by all models except those that appropriately consider the turbulence effects. Based on the results, a hybrid drag model is proposed that significantly improves the prediction of the void fraction.