Research On Air Valve Protection Water Hammer Of Long Distance Pump Water Delivery System

In the water transportation of long distance project,Air valves are the most widely device used in water hammer protection.When water hammer occurs,at the end of the air valve exhaust,Excessive exhaust valve hole diameter is very easy to cause water hammer of cavities collapsing;If the diameter of the exhaust valve hole is too small,the effect of water hammer protection cannot be achieved.Therefore,for the main problems of air valves in practical engineering applications,Two new air valve water hammer protection devices are proposed.New air valve device 1 and 2,And the mathematical models of two new air valve devices has been established.And also,the national utility model patent has been approved.For the two new air valve water hammer devices,In the system consisting of an air valve and a controllable valve,The gas mass flow of both intake and exhaust gases has been Innovatively combined,And the mathematical models has been Listed and solved,Combined with specific engineering example,The effect of protect the water hammer by the new air valve device 1 and device 2,the program is written by MATLAB language for numerical calculation simulation.Then compare and analyze the results of the program running,The effects of multiple parameters of the butterfly valve at the beginning of the pump and the water hammer protection device of the new air valve on the water hammer protection effect are studied.In the program,the optimization algorithm is Innovatively used to optimize the calculation of relevant parameters.The main research results obtained are as follows:(1)Summarize and analyze the previous researches on the basic theory of water hammer and water hammer protection measures,Take the pump water delivery of long-distance project of an industrial park in Shaanxi as an example.Establish a water hammer calculation model of the pump water delivery system.Analysis of the working conditions of the water hammer occurring when the long-distance pump water delivery system pump stops running,When studying two new air valve devices as water hammer protection measures,Different intake and exhaust pressures correspond to the determination method of the controllable valve opening procedure.(2)Two new air valve water hammer protection devices are proposed.The mathematical model of the new air valve device 1 and the new air valve device 2 is established by the characteristic line method,including mass flow characteristics and device boundary conditions.(3)Combining the specific engineering examples,analyze the working conditions of the long-distance pump water delivery system when the water hammer is stopped,and study the determination of the different inlet and exhaust pressures of the two new air valve devices corresponding to the controllable valve opening procedure.(4)The sub-program 1 of scheme B has been selected for the water hammer protect ion scheme.That is,a gradient of exhaust gas can meet the relevant specifications.The p arameters of the scheme are the two-stage closing butterfly valve closing time is t1=13s,Total valve closing time is t2=345s,,Angle after the end of the fast closing is ct1=30°,Relativeair intake opening degree is x(4)=0.53,Exhaust pressure gradient is x(5)=0.04,Rel ative exhaustopening degree 1 is x(6)=0.08,Relative exhaust opening degree 2 is x(7)=0.01.