The effect of boundary conditions and droplet entrainment on severe slugging using a Lagrangian slug tracking model

• Published in: International journal of multiphase flow 2016-10, Vol.85, p.245-257
• Main Authors: Smith, Ivar Eskerud, Nydal, Ole Jørgen
• Format: Article
• Language: English
• Subjects: Closed loop; Droplet entrainment; Gas–liquid pipe flow; Severe slugging; Slug tracking
• ISSN: 0301-9322; 1879-3533
• DOI: 10.1016/j.ijmultiphaseflow.2016.06.014

•Slug tracking simulations of large scale severe slugging experiments are presented.•Constant pressure and closed loop boundary conditions are compared.•The importance of a droplet field is investigated.•The simulations are shown to give fast and accurate predictions. This study presents a Lagrangian slug tracking model for prediction of slug flow in multiphase flow pipelines. Simulations are compared with severe slugging experiments from the SINTEF Large Scale Multiphase Laboratory with 0.189m inner diameter and a length of about 1000m. The fluids used in the experiments are nitrogen and naphtha, and the system pressure is 25bar. The model is shown to give fast and accurate results within the experimental accuracy without the need for a sub-grid model, as long as the grid size is not too large around the riser bottom where the liquid blockage occurs. It is also shown that simulations using a constant pressure boundary condition at the outlet are not always adequate, as the pressure fluctuations in the receiving facilities can significantly affect the flow. Furthermore, we show that the inclusion of a droplet field has a significant impact on the predicted slugging periods. [Display omitted]