Reducing the effects of water hammer phenomenon in pipelines by changing the closing rate of line break valve (LBV)

Line break valves in pipelines are used to prevent environmental hazards caused by the entry of fluid into the surrounding. The operation of these valves leads to sudden changes in pressure and velocity, resulting in the occurrence of the water hammer phenomenon. The water hammer pressure will cause serious problems such as the destruction of pipelines and transmission line equipment and tools. Due to the salinity of water, when a fracture occurs, the amount of water that enters the surrounding is environmentally essential, so the use of several LBVs is vital. This paper investigated a water transmission line with a total length of 337 km that transfers saline water from Khoor Moosa to Azadegan plain. This study discussed the closing of the valve at different rates and the solution to reduce its destructive effects. WaterGEMS V8i software and Hammer V8i software are respectively used to perform a steady flow simulation and damping flow analysis for this phenomenon. The results obtained from the steady-state flow simulation are the initial conditions in the damping flow calculations. Then, by reducing the closing rate of the valve in 6 different scenarios, the volume of air chambers decreased. Finally, the results led to creating a linear relationship between the valve closing rate and the capacity of the air chamber. The optimal model for this rate depends on reducing the construction cost as well as the environmental hazards caused by discharged water.