The Numerical Simulation Of Water Hammer In Water Piping System And Response Of Pipe Construction Under Water Hammer

As China’s economy has been developing faster and faster, China’s urban waterdemand is increasing rapidly. Unfortunately, China’s per capita water resources isscarce with its uneven distribution in space and time.So the contradiction betweenwater supply and demandare increasingly intensified.To ease the contradiction, Chinahas begun the construction of a number of long-distance water supply piping systemsengineering. When the pipeline system works in normal operation, water hammereffect (a special hydraulic transition process)may occur among internal piping systemdue to some external factors sudden excitation.Water hammer effect can bringdifferent levels of impact to the entire or partial pipeline system, even it is possible tobring serious projects accident.In order to conduct a comprehensive analysis for the water hammer process andaccurately capture the inner wall pressure distribution while the water hammer effectoccurring, this paper researches bothone-dimension and three-dimensionwaterhammer effectbased on the characteristics method and computational fluid dynamics(CFD) method. Also pipeline’s transient response characteristics under the impact ofwater hammer are studied in this paper. The paper’s main works and key conclusionsare as follow:Firstly research on numerical calculation of one-dimensional water hammer iscarried out with three different off valve conditions, and reasonablevalve closingschemeis proposed by analyzing the research results. Secondly three dimensionalwater hammer is studied by using CFD numerical method, researches show that bothwater hammer characteristics are in good agreement, which means three-dimensionalwater hammer calculations can accurately reflect the occurrence of water hammerpressure jump and the process of water hammer wave attenuation. More over thecalculations can accurately capture the flow characteristics inside of the pipeline,especiallythe pressure distributionof the inner wall. Finally,this paper studied thepipeline structure’s dynamic response under the three-dimensional water hammershock. The study shows thatthe hazardous areas concentrate in each elbow and teeconnecting the mother pipe to branch pipe. And stress wave’s period of pipeline’s structureis similar to the water hammer wave’s cycle.The paper’s study of waterhammer has certain engineering guiding significance for the works about industrialwater piping system designing and maintenance operation.