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Effect of pressure‐sensitive demand on surge analysis
Author(s) -
Jung Bong Seog,
Boulos Paul F.,
Wood Don J.
Publication year - 2009
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.2009.tb09877.x
Subject(s) - surge , transient (computer programming) , transient analysis , on demand , surge tank , computer science , environmental science , reliability engineering , engineering , transient response , electrical engineering , multimedia , operating system
Traditional water distribution models solve the network problem by considering instantaneous demands lumped as nodal outflows. Such demand‐driven analysis assumes that demands are independent of pressures and can be met under all operating conditions. Under transient conditions, however, the resulting positive‐ or negative‐pressure surges can drastically alter the local pressures and affect the demand magnitude that can be extracted. A pressuresensitive demand representation is needed to assess the effect of pressure changes and produce more accurate transient results. A comparative study of demand formulations for surge analysis showed that the pressure‐insensitive demand assumption is intrinsically inaccurate and tends to overdesign surge protection devices. This overdesign results in unnecessary additional costs but does not necessarily ensure greater safety. The authors conclude that a pressure‐sensitive demand formulation should be used for surge analysis to adequately evaluate both system performance and the ultimate cost of system protection.