الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
It has long been known that the severity of transients in pipelines networks is underestimated.Little is known about the impact of water hammer in irrigation pipelines networks.
The objective of the present study is to investigate water hammer in irrigation pipelines networks.The aim is to determine the maximum and minimum heads along the pipelines of the networks due to pump power failure.The effect of protecting the irrigation pipelines networks by using two-way surge tank,and air chamber are also included in the present study.
To achieve this goal, basic partial differential equations based on one-dimensional homogenous flow model are formulated and solved by the method of characteristics.
Two computer models written in FORTRAN language are prepared considering several biundary conditions to define the irrigation pipelines networks.The boundary conditions in the network include the presence of pump stations, downstream or upstream constant head reservior,gradually or suddenly closing valves,junctions with constant or variable external demand,drippers,sprinkler,and pivot lines with sprinklers equally spaced.The models allow the use of different devices to protect the system against water hammer.To give numerically stable solutions, two approaches are applied in the computer models to select the appropriate value for the time interval of the characteristics grid.