Type of Document	Master's Thesis
Author	Alday, John Hane
URN	etd-11242009-020017
Title	The correlation of randomness with high tip losses in an axial flow fan stage
Degree	Master of Science
Department	Mechanical Engineering
Advisory Committee	Advisor Name Title Ng, Fai Committee Chair Moses, Hal L. Committee Member Vick, Brian L. Committee Member
Keywords	Fans (Machinery)
Date of Defense	1991-04-19
Availability	restricted
Abstract 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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