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On the preliminary design of axial fans: extending the validity of the flow assumptions over the whole hydraulic characteristic and improvement of modeling
Author(s) -
Semel Matthias,
Willinger Bettina,
Grilliat Julien,
Delgado Antonio
Publication year - 2014
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201410360
Subject(s) - hyperbola , rotational symmetry , flow (mathematics) , mechanics , point (geometry) , flow coefficient , work (physics) , mathematics , engineering , physics , mechanical engineering , geometry
In order to carry out a preliminary axial fan design, established assumptions are made onto the flow structure within the fan at the design point. As an example the very common hypothesis of radial equilibrium, states that the radial velocity component downstream the fan is zero, and that the flow in this area is axisymmetric. With the help of this hypothesis, the flow is idealized in order to draw quantitative conclusions. The present communication aims at extending these assumptions on the whole flow regime in order to help fan designers to reduce the try‐and‐error cycle number. An analytical formulation for axial fan velocity distributions at design and off design conditions is proposed for an arbitrary work distribution. It is shown that the total pressure characteristics can be described by means of hyperbola and straight line. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)