Flow field analysis and research of the flow characteristic of compound air valve with floating slab

The water hammer occurs frequently in the water conveyance system, especially in the long distance system. In order to prevent the occurrence of vaporization phenomenon in the pipelines caused by the power-off water hammer, installation of air valve is the most common water hammer protection measure. The air valve should not only discharge the air of the tube when the station start the pump, but also have the function that could pour large amounts of air rapidly into the pipe and release the air slowly when the phenomenon of water column separation and bridge again occurs in the pipeline. A composite air valve and the flow field model of air valve were established in the paper, and used the CFD software to simulate the flow field of different intake and exhaust conditions. The exhaust characteristics of the air valve were studied by analyzing the distribution of pressure field and velocity field of different conditions. The impact of different positions of floating slab, for the exhaust characteristic of the air valve was discussed, which could provide references for optimal design and application research of the air valve.