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Reconsideration of the fan scaling laws. Part I: Theory

  • Air International US Inc

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

Generalized Fan Scaling Laws (GSFL) are derived for the scaling of fan performance. These follow from first principles using the Navier-Stokes equations appropriate to rotating and swirling flows. Not surprisingly, both Strouhal and Reynolds number similarity must be maintained. Thus for a geometrically similar family of fans, dynamic similarity is only possible if ΩD/U = const and UD/v = const. If the second relation is solved for U and substituted into the first, it follows that full dynamic similarity is possible only if ΩD2/ v = const. This can be contrasted with the classical fan laws (CFSL) which for the same flow rate coefficient would imply that Q/ΩD3 (or U/ΩD) = const, implying that both fan size ratio and fan speed ratio are independent fan scaling parameters. Clearly for dynamic similarity to be maintained, the velocity and fan speed can not be varied independently (i.e. fan size and fan speed are not independent scaling parameters), contrary to the implications of the classical fan scaling laws. Further implications of the differences between the classical and generalized scaling laws for fan performance testing and design will be explored. Also several examples will be given in Part II as to how the generalized scaling laws can be applied in design practice.

Original languageEnglish
Title of host publicationProceedings of the 4th ASME/JSME Joint Fluids Engineering Conference
Subtitle of host publicationVolume 2, Part B, Symposia
EditorsA. Ogut, Y. Tsuji, M. Kawahashi
PublisherAmerican Society of Mechanical Engineers
Pages1307-1315
Number of pages9
ISBN (Print)0791836967, 9780791836965
DOIs
StatePublished - 2003
Event4th ASME/JSME Joint Fluids Engineering Conference - Honolulu, HI, United States
Duration: Jul 6 2003Jul 10 2003

Publication series

NameProceedings of the ASME/JSME Joint Fluids Engineering Conference
Volume2 B

Conference

Conference4th ASME/JSME Joint Fluids Engineering Conference
Country/TerritoryUnited States
CityHonolulu, HI
Period07/6/0307/10/03

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