Mechanistic Modelling of Two-phase Flow with Phase Change Consideration

In this article a mechanistic model is proposed to predict pressure drop, temperature gradient and phase holdup for oil-water-gas flows within pipeline-riser system. The model is suitable for two/three phase intermittent (slug) flows where oil and water phases are fully mixed. However, validation is also made for the other multiphase flow patterns. This approach makes use of a generalized model instead of semi empirical correlations so that the continuity governing equation is explicitly solved, reducing complexity of the present models in the literature survey. Furthermore, oil and water are assumed to have a homogeneous behavior to simplify three-phase flow equations. Another consideration in this model is the phase change effects during flash vaporization and condensation in the long distance pipeline-riser systems. The model predictions are compared with experimental data and OLGA commercial model. Results revealed assumption phase change in mechanistic models improved prediction over the range of investigated flow conditions.

Keywords:

Two-phase flow , Mechanistic Model , Phase Change , Pipeline , Riser , Pressure Drop , Temperature Drop