Transient Simulation of Water Hammer in the No-negative-pressure Distribution System

Pump units are the main part of the no-negative-pressure facility in the water distribution system.In order to achieve constant pressure of water supply and improve the life of pumps,starting pump,stopping pump and varying frequency are very common in the performance of the facility.In this article,the software of Flowmaster has been applied in network adjustment calculation based the data for the pumping stations with no-negative-pressure facility and pipe networks to predict the water hammer in starting pump,stopping pump and varying the frequency of pumps.The results represent that the model built by the author can predict the water hammer of the distribution system and water hammer is found to transfers along with the water pipe networks in starting pump,stopping pump and changing the frequency of pumps.After comparison of the results,smaller pressure change no less than 0.1 bar is found in the front part of network while pressure change over 0.03MPa emerges in the back part of network with the maximum of 0.337MPa,which never exceed the bearing level of pipes.