Research Of The Water Hammer Prevention Of Long-Aistance, Gravity Flow, Water Supply System With Or Without Branches

As the economy continues to steadily grow, the level of rural urbanization acceleratesfaster and faster, the scale of the cities is getting bigger and bigger and the population hasbecome increasingly concentrated, industrial, service and residential water consumption isalso growing. But the distribution of water resources in our country is uneven, which hindersthe pace of social progress on certain extent. Therefore, in recent years we carried out anumber of large-scale long-distance gravity flow water supply projects, which includeengineering with branch pipes and non-branch pipe engineering. Meanwhile, pipe burstingand other accidents continue to occur, which affect the normal operation of the water line,causing huge economic losses. In order to ensure the long-distance gravity flow water systemwhen there is branch pipe or no branch pipes are functioning properly, the water hammerprotection method class engineering analysis is an important direction.This article outlines the background of the research, and outlines the definition of waterhammer, the classification of water hammer and the reasons cause water hammer. Take someexamples of water hammer accidents in order to prove how badly the water hammer affectsthe living of residents and social economy, and introduce the history and achievements oftheoretical research of water hammer at home and abroad. Calculating basic principle andmethods of the water hammer prevention are to present; Giving the Boundary Conditions ofmany facilities; Making use of the calculator to carry on to imitate the calculation, with theMicrosoft Visual C++being the developing tool. Combined with engineering example andpiping models and with the use of computers, we do the simulation of long-distance gravityflow water system when there are branches or no branch manifold and water hammerprotection calculations.This paper comparatively explains the protection of water hammer in gravity flow andlong-distance water supply system with and without branch pipe combined with Chaxianindustrial water supply project. The paper also briefly explains the basic differential equationsof water hammer calculation and the basic principle of the characteristic line method with thefinite difference equation. According to the calculation method of the characteristic linemethod, different boundary condition equations are given. The flow of gas—liquid twophase flow and conversion process are related so as the reason of column separationphenomenon and the harm it leads to. And also the paper details the structure andcharacteristics of several types of pressure relief devices used in protection of water hammer, and the advantages and disadvantages and the use of norms are detailed as well. According tothe simulation, put forward the best protection against water hammer no matter there arebranches or not. At last, analyze and compare the water hammer protection method betweenthe two operating modes.The results of the study are not only important for bringing forward water hammerprotection method of the very single project, but also for other long-distance gravity flowwater hammer protection when there are branches or without branches.