Two-phase flow in vertical lines can represent unique challenges, especially for low velocities in large-diameter lines. See our video on Pipeline Simulation Tools for an introduction, with particular attention to the chilldown/prime and purge discussions.

In such cases, liquid tends to fall through the gas, perhaps collecting at the bottom. Or gas tends to rise through liquid without lifting it much. (See the Bubble Pump sample problem.)

For more information and to see sample solutions, click here to visit our Tips and Samples page, which includes links to the detailed problem description and drawing files in the CRTech User Forum.