Modeling of over-tip-rotor liners for the suppression of fan noise
Modeling of over-tip-rotor liners for the suppression of fan noise
Fan noise is one of the dominant sources of aircraft engine noise, both at approach and at takeoff. Improved attenuation of fan noise with acoustic liners and the reduction of fan noise at the source remain key technology challenges for civil aviation in the foreseeable future. Over-tip-rotor (OTR) acoustic treatments have been investigated experimentally during the last decade, and significant fan noise reductions have been measured, most recently using a single rotor and multiple lined circumferential grooves. This paper describes an analytical OTR prediction model in which the fan noise is modeled with point or distributed, static or rotating monopole and dipole sources based on Green’s functions for infinite hard or lined cylindrical ducts containing uniform mean flow; these are combined with an anechoic or unflanged inlet termination and an embedded finite length lined section in which the rotor-alone source is located with its OTR liner. OTR liner insertion loss predictions are obtained for comparison with data from the W-8 NASA experimental rig. These yield peak broadband in-duct noise reductions of up to 4 dB, in line with the measurements.
6361-6373
Palleja-Cabre, Sergi
b841a96c-05d1-4f08-a197-8693cb3a3f90
Tester, Brian J.
1bd4a793-131b-4173-93cc-3eca70b2d116
Astley, R. Jeremy
cb7fed9f-a96a-4b58-8939-6db1010f9893
November 2022
Palleja-Cabre, Sergi
b841a96c-05d1-4f08-a197-8693cb3a3f90
Tester, Brian J.
1bd4a793-131b-4173-93cc-3eca70b2d116
Astley, R. Jeremy
cb7fed9f-a96a-4b58-8939-6db1010f9893
Palleja-Cabre, Sergi, Tester, Brian J. and Astley, R. Jeremy
(2022)
Modeling of over-tip-rotor liners for the suppression of fan noise.
AIAA Journal, 60 (11), .
(doi:10.2514/1.J061661).
Abstract
Fan noise is one of the dominant sources of aircraft engine noise, both at approach and at takeoff. Improved attenuation of fan noise with acoustic liners and the reduction of fan noise at the source remain key technology challenges for civil aviation in the foreseeable future. Over-tip-rotor (OTR) acoustic treatments have been investigated experimentally during the last decade, and significant fan noise reductions have been measured, most recently using a single rotor and multiple lined circumferential grooves. This paper describes an analytical OTR prediction model in which the fan noise is modeled with point or distributed, static or rotating monopole and dipole sources based on Green’s functions for infinite hard or lined cylindrical ducts containing uniform mean flow; these are combined with an anechoic or unflanged inlet termination and an embedded finite length lined section in which the rotor-alone source is located with its OTR liner. OTR liner insertion loss predictions are obtained for comparison with data from the W-8 NASA experimental rig. These yield peak broadband in-duct noise reductions of up to 4 dB, in line with the measurements.
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e-pub ahead of print date: 7 October 2022
Published date: November 2022
Additional Information:
Funding Information:
This project was funded by the European Union’s Horizon 2020 research and innovation program under a Marie Sklodowska-Curie Innovative Training Network grant (agreement number 722401) within the SmartAnswer consortium. The authors gratefully acknowledge the advice and information provided by Rick Bozak (NASA Glenn Research Center) and the high-quality fan noise data that NASA has made available for this study. The authors thank Sjoerd Rienstra for the use of his eigenvalue solver routine and Hadrien Beriot for his support in obtaining the numerical solutions using the finite element software Simcenter 3D Acoustics. The authors would also like to acknowledge helpful discussions with Christopher Morfey.
Publisher Copyright:
© 2022 by S. Palleja-Cabre, B. J. Tester, and R. J. Astley.
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Local EPrints ID: 475200
URI: http://eprints.soton.ac.uk/id/eprint/475200
ISSN: 0001-1452
PURE UUID: e25b0081-be4b-4951-b229-7e10ba0e812e
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Date deposited: 14 Mar 2023 17:30
Last modified: 18 Mar 2024 03:42
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Brian J. Tester
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