Transient pressures can cause significant damage to force mains and pumping systems, leading to pump station down-time, sewage overflows or water loss, and costly repairs. Numerical modeling can help address the issue, but results can be difficult to understand or implement correctly. This presentation will use three case studies to explain water hammer and how numerical modeling helps to avoid problems with transient pressures in pumping and pipeline systems.
In the first case, an existing sewage force main experienced pressure damage. After monitoring data confirmed hydraulic transient presence, numerical modeling identified that installing a surge tank at the pump station would be the most effective mitigation strategy. Following the installation of the tank, field measurements closely agreed with pressures predicted by the modeling.
In the second case, monitoring equipment detected transient pressures during the startup of a new pump station. Using field measurements to calibrate a numerical model of the system, the team determined that the addition of flywheels on the pumps would address the issue. Field measurements closely agreed with pressures predicted by the modeling following the flywheel installations.
In the third case, a numerical modeling study performed during design led to a recommendation to install surge tanks at the pump station. Transient pressure measurements obtained during pump station startup closely agreed with those predicted in the numerical modeling study.
This presentation will detail the convincing evidence that transient pressure numerical modeling is a critical step for developing resilient force main and pumping system designs. Numerical modeling provides reliable data for developing a surge mitigation strategy and reliably assess when a surge mitigation strategy is successful.