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Broadband Noise Reduction of a Low-Speed Fan Noise Using Trailing Edge BlowingAn experimental proof-of-concept test was conducted to demonstrate reduction of rotor-stator interaction noise through the use of rotor-trailing edge blowing. The velocity deficit from the viscous wake of the rotor blades was reduced by injecting air into the wake from a continuous trailing edge slot. Hollow blades with interior guide vanes create flow channels through which externally supplied air flows from the blade root to the trailing edge. A previous paper documented the substantial tonal reductions of this Trailing Edge Rotor Blowing (TERB) fan. This report documents the broadband characteristics of TERB. The Active Noise Control Fan (ANCF), located at the NASA Glenn Research Center, was used as the proof-of-concept test bed. Two-component hotwire data behind the rotor, unsteady surface pressures on the stator vane, and farfield directivity acoustic data were acquired at blowing rates of 1.1, 1.5, and 1.8 percent of the total fan mass flow. The results indicate a substantial reduction in the rotor wake turbulent velocity and in the stator vane unsteady surface pressures. Based on the physics of the noise generation, these indirect measurements indicate the prospect of broadband noise reduction. However, since the broadband noise generated by the ANCF is rotor-dominated, any change in the rotor-stator interaction broadband noise levels is barely distinguishable in the farfield measurements.
Document ID
20050196703
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Sutliff, Daniel L.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
September 7, 2013
Publication Date
June 1, 2005
Subject Category
Acoustics
Report/Patent Number
AIAA Paper 2005-3028
NASA/TM-2005-213814
E-15171
Meeting Information
Meeting: 11th Aeroacoustics Conference
Location: Monterey, CA
Country: United States
Start Date: May 23, 2005
End Date: May 25, 2005
Sponsors: Confederation of European Aerospace Societies, American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 22-781-30-64
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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