Study On Safe Operation For The Water Supply System Of High-rise Building

Based on the background of a high-rise building water supply system,this project studies the water hammer and the safety of faucet cavitation in its operation.It provides theoretical analysis and data support for the safe operation of the water supply system.The main research contents and conclusions are as follows:(1)Through the construction of water supply pipe water hammer simulation experimental device,the variation law of water hammer pressure and flow in the pipeline under different closing periods was studied.That is,the shorter the faucet is closed,the pressure is larger and the flow decreased more quickly.(2)Through the application of FLOWMASTER software to the fluid project analysis of the actual project,the pressure fluctuations in the system are captured,and the peak pressure wave and water hammer in the system are observed.Studies have shown that in a 19-storey tall building,when the valves on the 4th and 15 th floors are quickly closed,a strong water hammer phenomenon occurs in the upstream position;when the high water tank suddenly stops the water supply,the water hammer phenomenon does not occur downstream;when the water pump suddenly stops running,a serious water hammer phenomenon occurs upstream of its outlet.(3)The simulation analysis of different water hammer protection devices shows that setting the pressure tank or expansion tank or delaying the valve closing time can effectively suppress the water hammer caused by the quick closing valve.And the pressure tank is set closer to the valve,the water hammer protection effect is better;set the pressure tank after the check valve of the pump outlet or the setting of the slow closing butterfly valve at the outlet of the water pump can effectively suppress the pressure oscillation caused by the water hammer of the pump.However,it is necessary to set the butterfly valve slow closing time reasonably.If the time is too long,the water in the pressure pipe will have a large amount of backflow,which will cause damage to the water pump.(4)The steady state numerical calculations of the internal flow field of the faucet were carried out at different opening degrees by using the FLUENT software.The flow law of internal flow field and the occurrence of cavitation under different opening degrees are analyzed.With the increase of the opening degree,the inside of the faucet gradually forms a high-speed area.When the opening degree is about 70 degrees,the impact of the water flow on the faucet is the most severe.The cavitation area and maximum vaporization rate of the valve core reaching a peak when the opening degree is 70 degrees.The cavitation phenomenon is the most serious when the faucet is at 70 degrees.Therefore,it is recommended to develop new products,design the faucet to skip the 70-degree use of the gear.And in daily life,pay attention to avoid the faucet to use at 70 degrees for a long time to ensure the safety of water supply.