Water Hammer Protection Technique Of Multi-stage Decompression Water Pipeline With Large Height Difference Gravity Flow

With the enlargement of city scale and the development and the population surge,the contradiction between supply and demand of fresh water resources in most regions of more and more serious problem.Many consider integratedly,inter-basin water transfer become the most effective measures to solve this problem.Every inter-basin water transfer project,from the early stage of the overall project design to the final operation have spent huge manpower and financial resources.Therefore,how to guarantee the safe and stable operation of inter-basin water conveyance project become the focus of the society.Inter-basin water conveyance project can safe operation depends largely on water hammer protection measures of water pipeline,therefore,in actual engineering,we need detailed analysis of water hammer for the water pipe is calculated to ensure the safe operation of the water pipe.In this paper,through the related concepts and theories of water hammer,the characteristics of water hammer wave transmission in pipelines and the hazards of poor exhaust in pipelines are introduced.The main characteristics of gravity flow water transmission projects and several common water hammer protection methods are pointed out.At the same time,combining with computer software simulation of long and large elevation difference in detail for the water conveyance project of gravity flow simulation,water hammer in pipeline hydraulic transition conditions is analyzed and several kinds of common water hammer protective equipment characteristics of the boundary conditions and their own decompression.In addition,the article mainly introduces the curtains with new type of valve-orifice type high proportion valve is given priority to a whole new kind of water hammer protection measures,nozzle type high curtains on valve is professor Yang Yusi developed a new type of valve,the valve set step-down and adjust the flow functions in one,realized the new breakthrough in terms of valve in China.At the same time,the nozzle type high curtains would fall to the hydraulic control valve,realize the automation of the water hammer protection,reduce the loss due to think improper operation.This paper takes the Baoerde Reservoir gravity water transport project in Shuanghe City,Xinjiang as an example,and calculates the water hammer protection through computer software simulation.According to different valve control time and pipeline water hammer pressure curve values,reasonable water hammer protection measures and reasonable closing time of pipeline end valves are given.At the same time,detailed water hammer calculations were performed on the water hammer protection effects of constant-speed buffer exhaust valves,water level control valves,flow regulating pressure regulating valves,and orifice-type high proportional flow control valves.It can be seen from the calculation results that the high-spray orifice proportional flow valve has a good pressure reduction and steady flow effect and has good safety and economy.Through the waterhammer calculation and analysis of this example of long-distance and large-height-difference water conveyance project,effective water hammer protection measures for long-distance high-difference gravity flow water pipelines are concluded.