Study of Water Hammer Protection in a Long-Distance Three-Branch Pressure Pipeline System

To study the water hammer problem in three branches of a long-distance water transmission tunnel, a water hammer calculation model for the tunnel-pipeline water transmission system is established using the separation method. The effects of different branch line valve shut-off times under the conditions of high water level, artesian flow, and low water level in the water conveyance system were evaluated in conjunction with the actual water diversion and transfer project and pumping station lift operation. Based on the calculation results, a water hammer protection scheme that combines the regulation of the high-pressure and low-pressure relief valves and the air valve is proposed. The results of a water hammer calculation show that using the water hammer protection scheme with a high-pressure relief valve, a low-pressure relief valve, and an air valve can significantly reduce the negative pressure and the maximum water hammer pressure in the three-branch, long-distance water transmission system. And a good water hammer protection effect can be achieved.