Numerical rebuilding of dynamic instabilities and forces in multiphase pipe bend flow

Abstract

The present paper focusses on the numerical rebuilding of different multiphase flow regimes in a medium scale pipe system (6 inch). Principal investigations are performed by CFD to initiate hydro-dynamic instabilities and develop them into the correct flow pattern (slug, stratified, etc.) at a given downwind position without applying artificial models or boundary conditions. The numerical predictions of the flow obtained by a volume of fluid CFD method (OpenFoam) are compared with available experimental data. Numerical investigations are performed with respect to grid resolution, initial conditions and turbulence modelling, but also for obtaining a representative, comparable set of numerical and experimental data. For different flow regimes from slug flow to stratified flow good agreement with the experimental data was achieved with respect to the predicted flow regime and topology but also the forces predicted on the bend. Especially the large variation of the root mean squared values but also peak-to-peak values of the forces are predicted well by the numerical solutions for the different flow regimes.