Calculation and simulation method for water hammer in gravity flow pipeline inhilly areas
In order to accurately predict and protect the water hammer damage of gravity flow pipelines in hilly areas,and improve the safety and reliability of water transmission pipeline,in respective of the characteristics of large drop,long distance and topographic relief of the gravity flow pipeline in hilly areas,it was proposed to divide the water transmission pipeline into curved sections and straight sec-tions with inclined angles.Using the limit idea,the curve fitting vectorization method based on tangent of the curved section was fitted to multiple equivalent short pipes with the same flow section along the center line of the pipeline.The combination of fitting equivalent short pipes and inclined straight pipes was used to calculate the water hammer,the numerical calculation model of gravity flow pipeline was established.A gravity flow pipeline water conveyance project in Qianyang County,Shaanxi Province was taken as an example to verify and analyze.By simulating the change law of water hammer pressure of the valve at the end of the pipeline at different valve closing times,it is concluded that the optimal valve closing time is 50 s≤T≤ 120 s,and corresponding water hammer protection schemes are pro-posed.The results show that the method has high accuracy in calculation and simulation,and it can provide reference for the construction and management of long-distance gravity flow pipeline water con-veyance projects in hilly areas.
hilly areagravity flow water pipelinecurved pipeclosing time of valvewater hammer simulation