AWWA JAW70292

Water column separation, the rupture of water columns in pressurized pipelines, can be triggered by low- or negative-pressure transients when the pressure falls to vapor pressure, causing the water to vaporize and effectively dividing the water column. This phenomenon must be avoided because it reduces system performance, generates annoying vibrations and noise, and severely damages equipment. In this article, a Lagrangian method that implements the numerical discrete vapor cavity model is proposed for simulating transient water column separation. This robust and straightforward model greatly improves the reliability of Lagrangian-based network transient analysis models and produces results identical to those obtained from an Eulerian- based implementation approach. Using the proposed model, utilities will be better able to identify regions in the distribution system that are susceptible to low- or negative-pressure surges and devise effective strategies to control transients. Installation of properly designed surge-protection devices can help prevent water column separation and avoid potential pathogen intrusion. Includes 27 references, table, figures.