Abstract
No direct general solution is possible of the water hammer equations. It is thus necessary to use either iterative techniques on a computer or a graphical method to obtain a solution. Most practical systems are not simple pipelines but have changes in section and branch pipes. The paper shows how it is possible to allow for changes in section and branches in the graphical method for the cases of a valve closure or a pump shut-down. The case of a surge tank with base throttle is also applied to a reservoir-turbine installation.
In many cases it is not necessary to carry out the exact calculation as the use of an equivalent system will be sufficiently accurate. For a pipeline with different diameters or wall thickness an equivalent simple pipeline can be used. The various suggestions are reviewed and compared for four valve closure cases.
For branch pipes or surge tanks some cases where the branches can be neglected are given. The method of allowing for friction in the graphical method, and the assumptions made, are also mentioned.
Two examples are included of comparison between the exact method and an equivalent system, with some experimental results.
Get full access to this article
View all access options for this article.