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Acoustic testing of a 1.5 pressure ratio low tip speed fan with a serrated rotor (QEP fan B scale model)A scale model of the bypass flow region of a 1.5 pressure ratio, single stage, low tip speed fan was tested with a serrated rotor leading edge to determine its effects on noise generation. The serrated rotor was produced by cutting teeth into the leading edge of the nominal rotor blades. The effects of speed and exhaust nozzle area on the scale models noise characteristics were investigated with both the nominal rotor and serrated rotor. Acoustic results indicate the serrations reduced front quadrant PNL's at takeoff power. In particular, the 200 foot (61.0 m) sideline noise was reduced from 3 to 4 PNdb at 40 deg for nominal and large nozzle operation. However, the rear quadrant maximum sideline PNL's were increased 1.5 to 3 PNdb at approach thust and up to 2 PNdb at takeoff thust with these serrated rotor blades. The configuration with the serrated rotor produced the lowest maximum 200 foot (61.0 m) sideline PNL for any given thust when the large nozzle (116% of design area) was employed.
Document ID
19740019183
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Kazin, S. B.
(General Electric Co. Evendale, OH, United States)
Paas, J. E.
(General Electric Co. Evendale, OH, United States)
Minzner, W. R.
(General Electric Co. Evendale, OH, United States)
Date Acquired
September 3, 2013
Publication Date
January 1, 1973
Subject Category
Propulsion Systems
Report/Patent Number
NASA-CR-120846
Accession Number
74N27296
Funding Number(s)
CONTRACT_GRANT: NAS3-12430
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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