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Active Noise Control of Low Speed Fan Rotor-Stator ModesThis report describes the Active Noise Cancellation System designed by General Electric and tested in the NASA Lewis Research Center's 48 inch Active Noise Control Fan. The goal of this study was to assess the feasibility of using wall mounted secondary acoustic sources and sensors within the duct of a high bypass turbofan aircraft engine for active noise cancellation of fan tones. The control system is based on a modal control approach. A known acoustic mode propagating in the fan duct is cancelled using an array of flush-mounted compact sound sources. Controller inputs are signals from a shaft encoder and a microphone array which senses the residual acoustic mode in the duct. The canceling modal signal is generated by a modal controller. The key results are that the (6,0) mode was completely eliminated at 920 Hz and substantially reduced elsewhere. The total tone power was reduced 9.4 dB. Farfield 2BPF SPL reductions of 13 dB were obtained. The (4,0) and (4,1) modes were reduced simultaneously yielding a 15 dB modal PWL decrease. Global attenuation of PWL was obtained using an actuator and sensor system totally contained within the duct.
Document ID
19970017613
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Sutliff, Daniel L. (AYT Corp. Brook Park, OH United States)
Hu, Ziqiang (General Electric Co. Schenectady, NY United States)
Pla, Frederic G. (General Electric Co. Schenectady, NY United States)
Heidelberg, Laurence J. (NASA Lewis Research Center Cleveland, OH United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1996
Subject Category
Acoustics
Report/Patent Number
E-10744
AIAA Paper 97-1641
NAS 1.15:107458
NASA-TM-107458
Report Number: E-10744
Report Number: AIAA Paper 97-1641
Report Number: NAS 1.15:107458
Report Number: NASA-TM-107458
Meeting Information
Meeting: Aeroacoustic
Location: Atlanta, Georgia
Country: United States
Start Date: May 12, 1997
End Date: May 14, 1997
Sponsors: American Inst. of Aeronautics and Astronautics, Confederation of European Aerospace Societies
Accession Number
97N19805
Funding Number(s)
CONTRACT_GRANT: NAS3-27571
PROJECT: RTOP 538-03-11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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