Title page for ETD etd-11242009-020017
|Type of Document
||Alday, John Hane
||The correlation of randomness with high tip losses in an axial flow fan stage
||Master of Science
|Moses, Hal L.
|Vick, Brian L.
|Date of Defense
The results of a test program incorporating a dual hot wire aspirating probe to radially
survey the by-pass duct downstream of an axial flow fan stage are presented. The probe
measures time resolved total temperature and total pressure from which isentropic
efficiency is calculated. The objective was to provide time resolved data to further the
understanding of the flow and aid in determining the source of high losses located near
the rotor tip. A technique for quantifying randomness of an unsteady flow is developed,
and the randomness of the surveyed flow is shown to correlate with the losses. A new
method of ensemble averaging instantaneous data is presented which produces an
identifiable blade passage profile even in a random flowfield where traditional techniques
often fail. Time averages of the aspirating probe data are shown to agree with
conventional steady-state measurements within the experimental uncertainties. Unsteady
features seen in the data are compared to similar features noted in the literature, and
contour plots of the ensemble averaged data and unsteady fluctuations are presented.
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