Evaluation of a Flow Simulator for Multiphase Pipelines
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This thesis concerns the terrain slugging capabilities of LedaFlow; it is showed that LedaFlow is indeed able to simulate terrain slugging type 1 and 2 in a S-riser geometry with air and water at atmospheric conditions, the results are comparable to experimental data.The new multiphase flow simulation tool LedaFlow is evaluated. This is developed by SINTEF and the LEDA partners, together with Kongsberg Oil & gas. The S-riser case, which shows challenging aspects regarding terrain slugging, has been used to test the slug capabilities of the tool. A short description of relevant modelling approaches is given together with a description of the LedaFlow simulator. A base case is built and used to simulate the S-riser case for a variety of flow conditions. The results are compared to experimental data.Since LedaFlow is a new simulation tool, it needs to be qualified against experimental data. Testing on the S-riser case should show if the tool is able to simulate severe slugging or not. The main objective is to find out whether or not LedaFlow handles severe terrain slugging. If it does not, the development team might want to consider improving or making a new model.LedaFlow is in development and during the thesis work period, several versions have been released. Only the results from the last two are presented in this report. The newest of these, the 2.07 pre, shows excellent stability regarding terrain slugging. Qualitatively, it is able to simulate details in the flow that also is seen in the experiments. The results for terrain slugging 1 are compared to experimental data, but both the slug cycle amplitude and period shows deviations. The inlet pressure amplitude deviation is about 12 – 69 %, and the period is about 51 – 99 %. The transition region between terrain slugging 1 and 2 is predicted, but the transition between terrain slugging 2 and steady slugging not correctly predicted. Previous versions did not show good stability on the terrain slugging, in the 2.06 this was partly due to a bug regarding bubbly flow.It is concluded that LedaFlow 2.07pre is able to simulate terrain slugging type 1 and 2, which means there is no need for a new model for slug flow. However, the accuracy of the results may be questioned, which means that certain adjustments and improvements are needed.