AWWA JAW27634

Transient pressures (water hammer) must be taken into account when selecting the size and strength of pipe, sizing surge-suppression equipment, and specifying system operating rules. However, analysts frequently neglect transient conditions, particularly in complex systems such as distribution networks. Computer techniques make it possible to analyze distribution systems under a wide range of flow conditions and with relatively few restrictions. This article emphasizes that the details of how a hydraulic system is modeled or represented can have a critical impact on the predicted transient conditions. Fluid properties relating to water hammer are explained, and the origin of transient conditions is described. The author debunks three myths: (1) maximum steady-state velocities produce maximum transient head change, (2) looped or branched configurations alleviate water hammer, and (3) if one surge-protection device is good, then two or more are better. Examples are presented of the dangers of oversimplifying either the physical system or the operating conditions. Includes 2 references, figures.

Product Details

Edition:

Vol. 82 - No. 7

Published:

07/01/1990

Number of Pages:

9

File Size:

1 file , 1.7 MB