The Study On Numerical Simulation Of Water Hammer In Long Distance Water Gravitation Transportation Project

With development of city constructions and the improvement of people's living level,more and more long distance water transfer projects appear,the safety of water transportation at tracts people's attention.As an energy saving and efficient water transportation pipeline system,the safety of long distance water gravitational transportation pipeline system also attracts people's attention.The effective measures to long distance and large—scale regional water gravitational transportation pipeline system are proposed by simulation of this type's water hammer protection in the article.Water hammer has a great influence on the operation of water supply projects.The disconnection water hammer was greater than other water hammer. Many water supply projects suffered serious damage because of disconnection water hammer,it caused great losses of the people's production and life.Therefore, calculation of long-distance and high-lift water supply project hydraulic transition,has become an important task to ensure the safe of operation of water supply projects. Only did Accurate and reasonable numerical simulation of hydraulic transients,and then take the necessary and reliable water hammer protection measures, can ensure the safe operation of water supply project.The primary coverage is as follows:(1)Based on previous research,summarized the various flow patterns in Water pipeline,and the transformation between flow, and boost the pipeline balloon campaign issue,the most harmful and exhaust pipe Best way is discussed.(2)Summarizes the long-distance water pipeline gravity flow of water hammer protection technology, and carried out a systematic analysis two types of commonly used measures of water hammer protection to the piston valve,two-stage butterfly valve.(3)Combined with previous research,described the basic theory of the long-distance gravity water hammer calculationthe basic equations of water hammer and the method of characteristics,as well as the basic principles for protection and valve adjustment valve in pressure pipe valve,and give boundary conditions of the pipeline to reduce valve piston,two-stage pipeline butterfly valve and the Simple pipeline and complex piping.(4)This article focuses on the intake valve in the long-distance gravity flow water hammer protection application,details of the intake valve of the protective principle,classification,technical performance, as well as equipment selection,set the technical points of the intake and exhaust valves and related issues to some extent the research and concluded,and establish the mathematical model of calculation of water hammer for exhaust and intake valve,gives the calculation of the boundary conditions.(5)Visual Basic6.0 as the development language used to prepare a long-distance gravity water hammer protection for computer program. With an example,on a piston valve and two-stage butterfly valve closing valves for water hammer did the numerical simulation and analysis and comparison,obtained in long-distance gravity flow pipeline protection,the protective effect of piston valve better than a two-stage butterfly valve in the protective effect. The spreadsheet analysis gives the relationship valve piston valve timing and valve off the corresponding index.(6)By the process of water hammer protection a preliminary simulation to complex pipe in pipe road crossing, obtained the water hammer results for charge section and the branching pipe. compared with a relief valve,butterfly valve protection measures in the charge pipeline,and added into the exhaust valve protection valve on the pipeline has been optimized,so obtained a valve added to the exhaust valve is the most reasonable protective measures conclusions.