The correlation of randomness with high tip losses in an axial flow fan stage

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.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1991

Author dc:creator

• Alday, John Hane

Chair dc:contributor.committeechair

• Ng, Wing Fai

Committee members dc:contributor.committeemember

• Moses, Hal L.
• Vick, Brian L.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-11242009-020017

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/45984