Effects of Flow Regimes on Maximum Pressure in Offshore Pipelines

One of the most important factors in pipeline hydraulics and its protection against probable damages is keeping the pressure in a specific limit and also knowing how the pressure functions in the pipe through the pipeline route. Pressure function and pressure amount differ from each other regarding the phase of the fluid (single phase or multiple phase), and when gas phase (air) enters the pipeline, it affects the flow regime (simultaneously when gas-liquid flows there are such regimes as stratified, slug, etc.) and the applied pressure. The present study aims to investigate the effects of flow patterns and phases on maximum pressures along pipelines and to compare it with those of single-phase flows. Results show that the geometry and the percentage of entrained air are the main factors affecting flow patterns and pressure experienced by pipeline systems. For single phase mode, pressure is increased up to 26% in vertical upward flows compared to air-water flows with a different air percentage. Moreover, among various geometries considered in this research for two-phase flows, pressure at most has a 23- percent increase compared to that of single-phase flows.