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Record 1 of 1194
Active control of fan noise from a turbofan engine
Author and Affiliation:
Thomas, Russell H.(NASA Langley Research Center, Hampton, VA, United States)
Burdisso, Ricardo A.(NASA Langley Research Center, Hampton, VA, United States)
Fuller, Christopher R.(NASA Langley Research Center, Hampton, VA, United States)
O'Brien, Walter F.(Virginia Polytechnic Inst. and State Univ., Blacksburg, United States)
Abstract: A three channel active control system is applied to an operational turbofan engine in order to reduce tonal noise produced by both the fan and high pressure compressor. The control approach is the feedforward filtered-x least-mean-square algorithm implemented on a digital signal processing board. Reference transducers mounted on the engine case provides blade passing and harmonics frequency information to the controller. Error information is provided by large area microphones placed in the acoustic far field. In order to minimize the error signal, the controller actuates loudspeakers mounted on the inlet to produce destructive interference. The sound pressure level of the fundamental tone of the fan was reduced using the three channel controller by up to 16 dB over a 60 deg angle about the engine axis. A single channel controller could produce reduction over a 30 deg angle. The experimental results show the control to be robust. Simultaneous control of two tones is done with parallel controllers. The fundamental and the first harmonic tones of the fan were controlled simultaneously with reductions of 12 dBA and 5 dBA, respectively, measured on the engine axis. Simultaneous control was also demonstrated for the fan fundamental and the high pressure compressor fundamental tones.
Publication Date: Jan 01, 1993
Document ID:
19930039326
(Acquired Dec 28, 1995)
Accession Number: 93A23323
Subject Category: ACOUSTICS
Report/Patent Number: AIAA PAPER 93-0597
Document Type: Preprint
Publication Information: 10 p.
Publisher Information: United States
Meeting Information: AIAA, Aerospace Sciences Meeting and Exhibit; 31st; Jan. 11-14, 1993; Reno, NV; United States
Meeting Sponsor: AIAA
Financial Sponsor: NASA; United States
Organization Source: NASA Langley Research Center; Hampton, VA, United States
Description: 10p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ACTIVE CONTROL; ENGINE NOISE; NOISE REDUCTION; TURBOFAN ENGINES; CONTROLLERS; ERRORS; LEAST SQUARES METHOD; ROBUSTNESS (MATHEMATICS)
Imprint And Other Notes: AIAA, Aerospace Sciences Meeting and Exhibit, 31st, Reno, NV, Jan. 11-14, 1993
Miscellaneous Notes: Research supported by NASA
Availability Source: Other Sources
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