Analysis on air valve placement in long-distance water conveyance pipeline system

Water hammer is one of the key factors that can cause accidents by the burst of pressure pipeline. Important features and related reasons of accidents caused by water hammer in long-distance water conveyance pipeline system were introduced, and protection measures were presented. An long-distant raw water conveyance pipeline project was taken as an example to study on the influence of protective effect by different placement schemes of air valves based on hydraulic transient simulation and analysis. Results shows that largest number of air valves does not reach the best and unreasonable placement of air valves might be the cause of an accident. It is critical to select the proper location of air valves, it is necessary to pay more attention on local hump in the front of pipeline near the pump and put exhaust valves instead of inlet valves at the back of pipeline (except some higher hump location).