An implicit one-dimensional two-phase compressible flow solver for pipelines

This paper describes the use of a fully compressible two-phase flow model for the simulation of pipeline flows. The model is capable of dealing with a wide range of flow regimes, and is unconditionally well posed for transient computations. Applications described include both horizontal and vertical two-phase flows, air-water sedimentation flows and a two-phase shock tube problem. In all of these tests, good agreement is obtained with experimental or analytical solutions. Results simulating the rapid pressure surges encountered during the emergency shutdown of exit valves are also provided for two-phase pipeline flows. The use of advanced numerical methods, coupled with a fast implicit solver, enables accurate solutions to be obtained with considerably reduced computing times when compared with explicit schemes. The code developed here is capable of dealing with general equations of state (EOS) for each phase, and results are described using both an equivalent perfect and stiffened EOS for the liquid phase.