Acoustics – Sound-modifying means – Mechanical vibration attenuator
Patent
1997-01-13
1999-11-09
Williams, Hezron
Acoustics
Sound-modifying means
Mechanical vibration attenuator
415119, 381 715, 381 717, 381 718, 73570, F01D 2504
Patent
active
059795930
ABSTRACT:
A hybrid mode-scattering/sound-absorbing segmented liner system and method in which an initial sound field within a duct is steered or scattered into higher-order modes in a first mode-scattering segment such that it is more readily and effectively absorbed in a second sound-absorbing segment. The mode-scattering segment is preferably a series of active control components positioned along the annulus of the duct, each of which includes a controller and a resonator into which a piezoelectric transducer generates the steering noise. The sound-absorbing segment is positioned acoustically downstream of the mode-scattering segment, and preferably comprises a honeycomb-backed passive acoustic liner. The invention is particularly adapted for use in turbofan engines, both in the inlet and exhaust.
REFERENCES:
patent: H1357 (1994-09-01), Ng et al.
patent: 3936606 (1976-02-01), Wanke
patent: 3937590 (1976-02-01), Mani
patent: 3946830 (1976-03-01), Kutney et al.
patent: 4044263 (1977-08-01), Swinbanks
patent: 4104002 (1978-08-01), Ehrich
patent: 4109108 (1978-08-01), Crown et al.
patent: 4192336 (1980-03-01), Farquhar et al.
patent: 4199295 (1980-04-01), Raffy et al.
patent: 4419045 (1983-12-01), Andre et al.
patent: 4783817 (1988-11-01), Hamada et al.
patent: 5060471 (1991-10-01), Torkelson
patent: 5119427 (1992-06-01), Hersh et al.
patent: 5325661 (1994-07-01), Rice
patent: 5370340 (1994-12-01), Pla
patent: 5377275 (1994-12-01), Suzuki
patent: 5382134 (1995-01-01), Pla et al.
patent: 5498127 (1996-03-01), Kraft et al.
patent: 5702230 (1997-12-01), Kraft et al.
"Evaluation of Optimized Multisectioned Acoustic Liners", K.J. Baumeister, AIAA Article No. 79-0182R, vol. 17, No. 11, Nov. 1979, pp. 1185-1192.
"Duct Liner Optimization for Turbomachinery Noise Sources", Harold C. Lester and Jose W. Posey, Report No. NASA TM X-72789, Nov. 1975, pp. 1-19.
"Optimal One-Section and Two-Section Circular Sound-Absorbing Duct liners for Plane-Wave and Monopole Sources Without Flow", Harold C. Lester and Jose W. Posey, Report No. NASA TN D-8348, Dec. 1976, p. 51.
"Analytical and Experimental Studies of an Optimum Multisegment Phased Liner Noise Suppression Concept", David T. Sawdy, Roy J. Beckemeyer, and John D. Patterson, Boeing Report No. D3-9812-1, May 1976, pp. i-xvii, 1-91.
"Experimental-Analytical Correlation of Optimum Duct Acoustic Liner Performance", John D. Patterson, David T. Sawdy, and Roy J. Beckemeyer, Report No. A76-25856, Mar. 1976, p. 12.
"Optimum Segmented Acoustic Liners for Flow Ducts", David T. Sawdy, Roy J. Beckemeyer, and John D. Patterson, Report No. A76-25129, Nov. 1975, pp. i-iii, 1-47.
"Acoustic Theory of Axisymmetric Multisectioned Ducts", William E. Zorumski, Report No. NASA-TR R-419, May 1974, pp. iii, 1-32.
Modal Propagation Angles in Ducts with Soft Walls and Their Connection with Suppressor Performance, E.J. Rice, Nasa Lewis Research Center, Cleveland, Ohio, Mar. 12-14, 1979, pp. 1-9.
"Effects of Multi-Element Acoustic Treatment on Compressor Inlet Noise", R.E. Kraft and J.E. Paas, AIAA Paper No. 76-515, Report No. A76-38043, Jul. 20-23, 1976, pp. 1-10.
Hersh Alan S.
Rice Edward J.
Walker Bruce E.
Hersh Acoustical Engineering, Inc.
Miller Rose M.
Williams Hezron
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