Water hammer analysis

Sudden changes in the flow rate of water in the pipeline due to starting or stopping the pump can cause a significant increase or decrease in the pipeline pressure and damage the pipeline, pumps, valves, and other equipment. This pressure fluctuation is called water hammer, and the analysis of water hammer is an indispensable tool for ensuring the safety of water supply systems.
Using Ebara’s technology, it is possible to use numerical analysis to predict the fluctuation of pressure generated in water pipelines due to water hammer. If the analysis predicts a water hammer problem, operators can perform water hammer calculations including equipment for water hammer prevention (flywheels, surge tanks, air chambers, etc.) to determine optimal water hammer countermeasures as needed.

We use our proprietary characteristic-curve based on TRAP III fluid transient analysis program to analyze the water hammer phenomenon. TRAP III has a history of more than 40 years of use and has been utilized in many applications. Its high analysis accuracy has been fully verified by comparison with many water hammer tests done in the field.

This analysis program supports complex pipelines including branching and merging, and provides many characteristics as boundary conditions for various types of equipment (pumps, valves and tanks), enabling analysis of water hammer at a level that rivals actual water supply systems. It offers the type of advanced water hammer analysis distinctive to pump manufacturers that owns extensive equipment characteristics for pumps and valves.

It enables the analysis of slamming, which is a phenomenon in which a swing-type check valve closes with a loud impact sound when the pump stops. In particular, it makes it possible to select a check valve that does not generate the slamming phenomenon. It also allows for calculations that take into account water column separation.