aircraft noise reduction : airbus industrial needs in ... · presented by: hervé batard aircraft...

Presented by: Hervé Batard

Aircraft noise reduction : AIRBUS industrial needs in terms of new materials for nacelle liners

Journées scientifiques de l’ONERA - January 16th, 2003

January 2003

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Summary

• Noise & aircraft design

• Propulsion noise reduction�Low noise configurations and flight procedures�Engine source�Nacelle geometry and liners

• Liner impedance requirements

• Conclusion

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Aircraft noise: A complex mix of different sources

Take-off

Com

bust

or

Jet

Engi

ne T

otal

Airc

raft

Tota

l

Airfr

ame

Turb

ine

Com

pres

sor

Fan5 dB

Approach

Com

bust

or

Jet

Engi

ne T

otal

Airc

raft

Tota

l

Airfr

ame

Turb

ine

Com

pres

sor

Fan

5 dB

• Take-off: Jet & Fan

• Approach: Fan & airframe

FAN ANDCOMPRESSOR NOISE

AIRFRAME NOISEFAN, TURBINE ANDCOMBUSTOR NOISE

JET MIXING NOISE

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Long Range aircraft sensitivity to noise sources

Jet Airframe Inlet fan

Aft fan

Turbine & combustion

∆∆∆∆EPNLAIRCRAFT∆∆∆∆EPNLSOURCE

Departure noise

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© Airbus 2002 Computer Graphics by I3M

Noise: An integral part of the design process

CONCEPT

Requirements-550 pax…-Ch.4 - x...

DEFINITION

A3XX Structure

Performance

Maintainability

Aerodynamics

Multidisciplinaryvalidation

EPNL

P

Risk assessment

P

EPNL

P

DEVELOPMENT

Noise reduction

Selected design

Perfo

rman

ce

X X

XX

X

X

Trade-offs

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� Airbus 2002 Computer Graphics by I3M

Noise reduction results fromcomplete aircraft optimisation

Nacelle attenuation

Engine noise

Airframe noise

Low speedperformance

Noise abatement procedures

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Summary




• Conclusion

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Low noise configurations

Masked sources• inlet fan• combustion• turbine

Masked sources• inlet & aft fan• compressor• combustion• turbine

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Engine noise reduction technologies

Active Stators

ANTLE & High Speed LP Turbines

Integrated Fan Design UHBR Fan LP Compressor

Low Noise Fan Nozzle

Low Noise Core Nozzlew internal/external Plug

Different Treated PlugTechnologies

HF Treated Nozzle

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Nacelle noise reduction technologies

Active Wall-Mounted System

Intake LipLiner

Exhaust Splitters(radial or circum.)

AdaptiveLiner

NegativelyScarfed Intake

ImprovedImpedance

Liner

0 Splice Liner

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Summary




• Conclusion

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Engine noise features

Engine noise is a complex mix of broadband noise and tones

Spectre de bruit moteur à 2500rpm

70

75

80

85

90

95

100

105

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000Freq (Hz)

dB SPL

Fréquence (Hz)

BPF

Harmoniques du BPFSP

L (d

B)

Spectre de bruit mesuré

Décollage pleine puissance Spectre de bruit moteur à 2500rpm

70

75

80

85

90

95

100

105

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000Freq (Hz)

dB SPL

Fréquence (Hz)

BPF

Harmoniques du BPFSP

L (d

B)


Décollage survolSpectre de bruit moteur à 2500rpm

70

75

80

85

90

95

100

105

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000Freq (Hz)

dB SPL

Fréquence (Hz)

BPF

Harmoniques du BPF

SPL

(dB

)


Atterrissage

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Assessment of design conditions

1BPF 2BPF 3BPF 4BPF

Radiation-Frequency Analysis of Noise emergence(U/S fan case)

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Computation of optimal impedances

Optimal acoustic impedances

-8

-6

-4

-2

0

2

4

6

0 1000 2000 3000 4000 5000 6000 7000 8000

Frequency (Hz)

Nor

mal

ized

impe

danc

e

APPROACH Optimal resistanceAPPROACH Optimal reactanceSIDELINE BSN (Energy on m=n+/-2p) Opt. RSIDELINE BSN (Energy on m=n+/-2p) Opt. XSIDELINE BSN (Modal equidistribution) Opt. RSIDELINE BSN (Modal equidistribution) Opt. XSIDELINE BSN (Energy on m=n) Opt. RSIDELINE BSN (Energy on m=n) Opt. X

APPROACH 1, 2, 3 and 4BPF

SIDELINE BSN

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Possible liner candidates

Non linear SDOF liner : Reflective back skin + honeycomb + perforated face sheet

=> Features : non linear, sensitive to flow, weak efficiency bandwidth, easy to build

Linear SDOF liner : Reflective back skin + honeycomb + microporous face sheet

=> Features : linear, not sensitive to flow, better efficiency bandwidth

DDOF liner : Reflective back skin + honeycomb + micro porous septum + honeycomb + face sheet (perforate or micro porous)

=> Features : large efficiency bandwidth, difficult to build

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Industrial needs

In some cases, classical liners are not able to reach all optimum impedance targets together.

Acoustic impedances - Approach Condition

-8

-6

-4

-2

0

2

4

6

315 400 500 630 800 1000 1250 1500 2000 2500 3150 4000 5000 6300 8000

Frequency (Hz)

Norm

aliz

ed im

peda

nce

Hence, there is a need to investigate new type of liners and/or new materials to improve noise reduction.

Porous materials remain good candidates !

Optimumimpedances

Resistance and reactanceof optimum 2DOF liner

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Summary




• Conclusion

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Conclusion

• Developing even quieter aircraft is necessary to ensure air transport sustainable growth

• Novel and powerful noise reduction means are needed especially to attenuate engine noise

• Limitation of current acoustic liners are well known and there is a need for improved technologies

• New materials should be investigated and porous materials are seen by AIRBUS as one of promising ways

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This document and all information contained herein is the sole property of AIRBUS S.A.S. No intellectual property rights are granted by the delivery of this document or the disclosure of its content. This document shall not be reproduced or disclosed to a third party without the express written consent of AIRBUS S.A.S. This document and its content shall not be used for any purpose other than that for which it is supplied.

The statements made herein do not constitute an offer. They are based on the mentioned assumptions and are expressed in good faith. Where the supporting grounds for these statements are not shown, AIRBUS S.A.S. will be pleased to explain the basis thereof.

AN EADS JOINT COMPANYWITH BAE SYSTEMS

aircraft noise reduction : airbus industrial needs in ... · presented by: hervé batard aircraft...

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