www.nasa.gov

Aircra&'Engine'Noise'Research'and'Tes3ng'at'the'NASA'Glenn'Research'Center'

Dave'Ellio;'NASA'Glenn'Research'Center,'Acous3cs'Branch'David.M.Ellio;@nasa.gov'

March'25,'2015'

https://ntrs.nasa.gov/search.jsp?R=20160014700 2020-07-31T07:20:36+00:00Z

www.nasa.gov

NASA'Glenn'Research'Center'

•  1941'IAircra&'Engine'Research'Laboratory'under'Na3onal'Advisory'Commi;ee'for'Aeronau3cs'(NACA)'

•  1958'I''Renamed'Lewis'Research'Center'and'incorporated'into'NASA'

•  1999'–'Renamed'John'H.'Glenn'Research'Center'•  Center'of'Excellence'in'Turbomachinery'•  Diversified'into'certain'areas'of'space'research/

management'e.g.'microgravity,'electric'propulsion,'space'power'and'communica3ons'

•  Main'facility'adjacent'to'Cleveland'Hopkins'Interna3onal'Airport,'second'facility'Plum'Brook'near'Sandusky'

www.nasa.gov

Glenn Core Work Areas

3

www.nasa.gov

Acous3cs'Branch'within'NASA'Glenn'Organiza3on'

4

Office of the Director (A) Director

Deputy Director (A) Associate Director (A) James M. Free

Dr. Janet L. Kavandi Janet L. Watkins

NASA Safety Center (N)

Alan H. Phillips

Office of the Chief Financial Officer (B)

Laurence A. Sivic

Office of the Chief Counsel (G)

J. William Sikora

Plum Brook Station (H)

David L. Stringer

Office of Diversity and Equal Opportunity (E)

Lynda D. Glover

Facilities, Test and Manufacturing Directorate (F)

Thomas W. Hartline

Aeronautics Directorate (K)

Therese M. Griebel

`

Office of the Chief Information Officer (V)

Sean M. Gallagher

Center Operations Directorate (C)

Robyn N. Gordon

Office of Technology Incubation and Innovation (T)

Dr. John M. Sankovic

Research and Engineering

Directorate (L)

Dr. Rickey J. Shyne

Space Flight Systems

Directorate (M)

Bryan K. Smith

Safety and Mission Assurance

Directorate (Q)

Anita D. Liang

Office of Human Capital Management (J)

Lori O. Pietravoia

Associate Director for Strategy (A)

Dr. Howard D. Ross

PS–01242–0414 ver. 03 /13/ 2015

www.nasa.gov

For more information on Glenn’s Organizational Structure please visit: http://www.grc.nasa.gov/WWW/OHR/Orglist/

Glenn Research Center at Lewis Field

Encl

osur

e 1

Research and Engineering Directorate (L)

Communications and Intelligent

Systems Division (LC)

Power Division (LE)Materials and

Structures Division (LM)

Systems Engineering and

Architecture Division (LS)

Propulsion Division (LT)

Management Support and

Integration Office (LB)

Chief Engineer Office (LA)

Research and Engineering Directorate

www.nasa.gov

For more information on Glenn’s Organizational Structure please visit: http://www.grc.nasa.gov/WWW/OHR/Orglist/

Glenn Research Center at Lewis Field 6

Propulsion Division (LT)

Turbomachinery and Turboelectric Systems

Branch (LTE)

Inlets and Nozzles Branch(LTN)

Icing Branch (LTI)

Acoustics Branch (LTV) Electric Propulsion Systems Branch (LTS)

Propulsion Systems Analysis Branch (LTA)

Chemical and Thermal Propulsion Systems

Branch (LTR)

Combustion Physics and Reacting Systems Branch

(LTX)

Engine Combustion Branch (LTC)

Fluid Physics and Transport Processes

Branch (LTZ)

Thermal Systems Branch (LTT)

Fluid and Cryogenic Systems Branch (LTF)

Encl

osur

e 2Propulsion*Division*

www.nasa.gov

NASA'Aeronau3cs'Programs'

•  Most'acous3c'research/tes3ng'done'under'NASA'agency'programs/projects'with'milestones'

•  Some'Example'Programs/Projects'–  Previous'

•  Late'1990’s/Early'2000’s'I''Advanced'Subsonic'Technology'(AST)'and'Quiet'Aircra&'Technology'(QAT)'

–  Recent'•  Fundamental'Aeronau3cs'Program'I'Subsonic'Fixed'Wing'Project'–'longer'

range'technology'•  Environmentally'Responsible'Avia3on'Program'–near'term'technology'•  Advanced'Air'Vehicles'Program'–'Advanced'Air'Transport'Technology'I'present''h;p://www.aeronau3cs.nasa.gov/programs.htm'

www.nasa.gov

* Projected benefits once technologies are matured and implemented by industry. Benefits vary by vehicle size. N+1 and N+3 values are referenced to a 737-800 with CFM56-7B engines; N+2 values are referenced to a 777-200 with GE90 engines.

** ERA’s time-phased approach includes advancing “long-pole” technologies to TRL 6 by 2015. *** CO2 emission benefits depend on life-cycle CO2e per MJ for fuel and/or energy source used.

!  To reduce the impact of aviation on the environment, NASA has adopted a set of aggressive noise, emissions, and fuel burn goals for future subsonic transport aircraft.

!  The environmental goals are traceable to the U.S. National Aeronautics Research and Development Plan.

-52

U.S. Subsonic Transport Noise Goals'

8'

www.nasa.gov

777-200

A330-300

MD-90-30

MD-11

A320-214 747-400

A300-600R

767-300ER

757-200

MD-87 MD-82

B-747-300

A300B4-620

A310-222

MD-80

B-747-200

B-747-SP DC-10-40

B-747-200

A300

B-747-200

B-747-100

B-737-200 B-737-200

B-727-200

DC9-10

B-727-100

B-727-100

-20.0

-10.0

0.0

10.0

1960 1970 1980 1990 2000 2010 2020 Year of Certification

Average Noise Level

Relative to

Chapter 3 (EPNdB)

Chapter 2

Chapter 3

Chapter 4

B-737-300 B-737-800

B-737-900 A320-232

B-777-300

A340-541

A318-112

DC8-20

B-707-100

B-787

B-747-8F A380-841

B-737-900ER

A330-243

Chapter 14

1992 Small Twin Ave. Production

AST TRL 6 Goal

QAT TRL 4 Goal

N+1 TRL 4-6 Goal

N+2 TRL 4-6 Goal

1997 Small Twin Baseline

Subsonic Aircraft Noise Levels & Research Goals

9'

www.nasa.gov

Acoustics Branch Research Focus

Conduct'research'for'reduc3on'of'aircra&'propulsion'system'noise''

•  Focus'on'engine'noise&reduc+on&technologies'that'maintain'acceptable'aerodynamic'performance'for'both'subsonic'and'supersonic'applica3ons.'

•  Perform'diagnos+c'experimental'and'analy3cal'studies'to'understand'underlying'fundamental'physics'of'noise'genera3on'and'mi3ga3on.'

•  Engine'noise'predic+on&codes'are'developed'and'validated'using'experimental'data'ranging'from'empirical'to'Computa3onal'Aeroacous3cs'(CAA)'tools'that'directly'compute'the'noise'genera3on'and'propaga3on.'

•  Maintain'worldIclass'experimental'capability'in'the'9x15'Low'Speed'Wind'Tunnel,'AeroIAcous3c'Propulsion'Lab,'and'the'Acous3cal'Tes3ng'Lab.'Use'capability'for'concept'valida3on,'to'generate'benchmark'databases'for'code'development,'and'available'for'reimbursable'use.'

10

www.nasa.gov 11

Cross'Sec3onal'Drawing'of'Turbofan'Model'used'in'Wind'Tunnel'Tes3ng'

www.nasa.gov

LTV/ Acoustics Branch '

12

Noise Diagnostics • Concept Investigation

• Engine Noise Source Identification

Noise Prediction • Model Development

• Simulations

Noise Reduction • Concept Development

• Testing & Evaluation

GTF Fan

Honeywell Engine Test

Fan Noise Prediction

Jet Flow & Noise Simulation

Jet Flow PIV Data

Jet Flow Prediction

Swept Stator for Fan Noise Reduction

Nozzle Chevrons for Jet Noise Reduction Trailing Edge Blowing for Fan Noise Reduction

Jet Flow Turbulence via PIV

www.nasa.gov 13

Noise'Reduc3on'

Over-the-Rotor metal foam acoustic treatment fan case

Acoustically treated soft vanes Propulsor

Exhaust Systems

Actuator'Off'

M'1.3'Jet'

Actuator'On'

Active control of jet

Model hardware

Passive 3-D nozzle concepts

Source Noise, Attenuation, Cancellation

www.nasa.gov 14'

Diagnos3cs'

In a cooperative effort with NAVAIR, phased array measurements were obtained for an F404 engine with a modified nozzle that included chevrons

Tip vortex

Particle Image Velocimetry (PIV)

CMFI Pylon

Array Peak Level

No Pylon

Array Peak Level

Flush Kevlar Acoustic Cover

Pressure Sensitive Paint

Phased Arrays, PSP, PIV, HW/HF, Rotating Rake, FF Microphone

www.nasa.gov 15'

Predic3on'

FEGV Wake Interaction, RANS Based

Empirical (ANOPP), RANS Based, Non-Linear High Order

Open Rotor RANS

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C0 Z1

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C0 Z4

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C0 Z9

10-1 100

60

80

100

120

140

160

Strouhal NumberPo

lar A

ngle

from

Inle

t ( °

)

TCON C90 Z1

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C90 Z4

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C90 Z9

10-1 100

60

80

100

120

140

160

Model ΔSPL: Ma = 1.329, Tsr = 1.76, Mfj = 0.1

-3

-2

-1

0

1

2

3

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C0 Z1

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C0 Z4

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C0 Z9

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C90 Z1

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C90 Z4

10-1 100

60

80

100

120

140

160

Strouhal Number

Pola

r Ang

le fr

om In

let (

°)

TCON C90 Z9

10-1 100

60

80

100

120

140

160

ΔSPL: Ma = 1.33, Tsr = 1.76, Mfj = 0.25

-3

-2

-1

0

1

2

3

Twin Jet Effect: Sample, ΔSPL dPSD = (PSD Modeled) – (PSD Measured) Fine Turbo, Open Rotor RANS

Broadband Aeroacoustic Stator Simulation (BASS) Code, ANCF simulation, high order, high accuracy

www.nasa.gov

Distribu3on'by'Technical'Focus''

16

www.nasa.gov

Facili+es&and&Advanced&Tes+ng&Techniques&for&

Database&Genera+on&and&Concept&Evalua+on&for&

Exhaust&Systems,&Fan&Systems,&Open&Rotors,&and&

small&engines.&

Aero-acoustic Propulsion Lab

Acoustical Testing Lab (ATL)

9x15/8x6 Wind Tunnel

Small Hot Jet Acoustic Rig (SHJAR)

Advanced Noise Control Fan

(ANCF)

Nozzle Acoustic Test Rig (NATR)

17'

L

CW-17 Free Jet Facility

www.nasa.gov

Advanced'Noise'Control'Fan'Design,'test,'and'evalua3on'for'technical'riskImi3ga3on'of'most'of'the'innova3ve'fan'noise'reduc3on'technologies'developed'by'NASA'over'the'past'20'years.''

1992&–&2014&:&&LowNTRL&research&performed&on&ANCF&enabled&the&advancement&of&

mul+ple&noise&reduc+on&and&measurement&technologies.&

Inves&ga&ng)transferring)the)ANCF)to)a)university)to)jointly)operate)the)ANCF)to)maintain)research)capability,)and)provide)relevant)STEM)opportuni&es,)in)the)area)of)fan)acous&cs.))

Highly'flexible,'fundamental'test'bed.''Mul3ple'configura3ons,'including'rotor'alone.'4Ifoot'diameter'ducted'fan'Low'speed:'(variable)'''''~1800'rpm,'V3p'~375'&/sec,'Mduct'~'0.15'

Used'to'provide'aeroIacous3c'database'and'to'evaluate'noise'reduc3on'technologies'

Data'acquired'by'externally'clocking'data'system'from'rig'tachometer'signal'

18

The'ANCF'has'been'used'in'over'6'internal,'8'external'programs'(2'reimbursable),'2'NRAs,'3'SBIRs,'and'2'Aero'Acous3c'Research'Consor3um'programs.'These'were'integrated'in'GRC’s'noise'reduc3on'program'milestones.'It'is'the'only'complete'aeroIacous3c'data/geometry'set'publically'available. 'Over'100'papers'wri;en'based'on'ANCF'data.'(~4'I6'per'AIAA'AeroIAcous3cs'Conference)'

www.nasa.gov

DGEN380&Turbofan&Engine'

The'DGEN'engine'is'the'world’s'smallest'turbofan:'it'is'intended'for'4I5'seat'twinIengine'Personal'Light'Jets'flying'under'25,000&'and'250kts.'The'DGEN'

engine'is'manufactured'by'Price'Induc3on.'

14”'

52”'

The'characteris3cs'of'the'DGEN380'enable'it'to'be'an'excellent'representa3on'of'modern'turbofan'engines.'

19

www.nasa.gov

Aircra&'Engine'Noise'Sources''

•  Fan'noise'–  Consists'of'broadband'and'tonal'–  Broadband'primarily'random'and'generated'by'rotor'alone''–  Tonal'(Blade'Passage'Frequency'and'harmonics)'generated'by'

rotor'wakes'impinging'on'stator'vanes,'correlated'to'sha&'orders'or'engine'RPM'

•  Jet'noise'–  Due'to'mixing'of'high'temperature'high'velocity'streams'with'

lower'velocity'lower'temperature'streams'•  Core'noise'

–  Produced'by'the'combus3on'process,'compressor'and'turbine'noise'

www.nasa.gov

Experimental'Fan'Noise'Tes3ng'

•  9x15'Low'Speed'Wind'Tunnel'Facility'•  Models''

–  Turbofan'–  Counter'Rota3ng'Open'Rotor'

•  Data'Acquisi3on'•  Data'Analysis'•  Noise'Reduc3on'Technologies'

www.nasa.gov 22

www.nasa.gov 23

www.nasa.gov 24

www.nasa.gov 25

www.nasa.gov

Power&Spectrum&Density&from&0&to&5&kHz&of&the&Counter&Rota+ng&Open&Rotor&Historical&Baseline&

Blades&at&6450&corrected&RPM&with&takeoff&pitch&angle&and&141&degrees&rela+ve&to&the&rear&rotor&&

pitch&change&axis.&Blade&Passage&and&Interac+on&Tones&are&labeled.''

www.nasa.gov

9x15'LSWT'acous3c'measurement'techniques'Objec3ve:'Examine'acous3c'measurement'techniques'to'improve'data'accuracy/increase'acquisi3on'efficiency.'

Techniques'tested:'•  Linear'Microphone'Array'•  Mul3Imicrophone'traversing'probe'•  Con3nuous'Traversing'Microphone'

Approach:''•  Design'and'test'techniques'and'compare'with'

present'acquisi3on'methods'

Results/Conclusions'•  Linear'array'compares'well'with'standard'traversing'

microphone'over'compressed'frequency'range'

•  3'headed'microphone'had'low'background'noise'level'rela3ve'to'single'mic'stand'while'allowing'two'addi3onal'azimuthal'angle'measurements'

•  Con3nuous'traverse'has'shown'excellent'comparison'with'discrete'traverse'and'has'ability'to'save'3me'

Frequency, Hz

PSD,dB

0 2000 4000 6000 8000 10000

Auto Spectra of Traversing Microphone vs Linear Array Cross Spectra at 90 degreesrelative to Rear Rotor Pitch Axis for Historical Baseline at 100% Design Speed, M=0.26 dB Plate Correction included for Linear Array

!

27

Linear'Array' 3'Mic'Traverse'

www.nasa.gov 28

Acous3c'Data'Acquisi3on'

•  Bruel'&'Kjaer''I  ¼”'Microphones'with'nosecones'I  Nexus'Signal'Condi3oning'Units'

•  RC'Electronics'Datamax'for'acquisi3on'using'200'kHz'sample'rate'•  One'traversing'microphone'for'capturing'model'direc3vity'

I  Previously'fixed'stop'I  Recently'converted'to'con3nuous'sweep'

I  More'direc3vity'resolu3on'I  Time'Savings'

•  Fixed'Microphones'•  Model'3ming'signals'(once'per'rev)'and'traverse'posi3on'recorded'•  Facility'system'records'tunnel'ambient'and'model'condi3ons'

•  Pressure,'Temp,'Humidity,'Mach'No.'•  RPM,'Angle'of'A;ack'

'

www.nasa.gov 29

www.nasa.gov

deciBels'

30

!!!" = 20 ∗ !"#!"(!!!"#

)!

!!!" = 10 ∗ !"#!"!!!"#

!!

!!!"# = 2.0!10!!!

www.nasa.gov

Acous3c'Data'Analysis'•  Data'taken'is'model'scale'–'frequency'scales'inversely'•  Fast'Fourier'Transform''I'3me'to'frequency'domain'•  Correc3ons'included'for'microphone'and'nosecone'calibra3ons'•  1'foot'lossless'–'results'o&en'projected'to'one'foot'distance'with'

atmospheric'a;enua3on'removed,'enables'comparison'of'data'taken'at'different'distances'

•  Usually'in'Power'Spectral'Density'(dB/Hz)'I'allows'direct'comparison'of'data'taken'at'different'sampling'frequencies,'different'bandwidths'

•  Overall'Sound'Pressure'Level'(OASPL)'–'Used'to'give'a'total'value'for'each'direc3vity'angle'measured'

•  Overall'Sound'Power'Level'(OAPWL)'–'Gives'a'single'value'for'the'acous3c'power'by'integra3ng'OASPL'for'each'angle'over'the'en3re'direc3vity'surface'

•  Effec3ve'Perceived'Noise'Level'(EPNL)'–'Common'NASA'and'industry'calcula3on'to'give'single'value'for'an'aircra&'condi3on'(e.g.'takeoff),''weights'frequency'bands'and'includes'a'3me'element'simula3ng'aircra&'flyover,'data'is'full'scale'and'usually'u3lizes'an'aircra&'configura3on'(medium'twin'engine'etc.)'

www.nasa.gov

Major'Challenge:'Reducing'noise'without'adversely'affec3ng'engine'

performance'or'efficiency''

www.nasa.gov

•  Cycle'Change'I'Higher'Bypass'Ra3o'–  Increase'amount'of'weight'flow'through'the'bypass'duct'while'reducing'flow'

through'core'engine'–  Results'in'larger'fan'diameter'–  Larger'fan'has'lower'3p'speed'while'maintaining'thrust'(noise'is'a'func3on'of'fan'

3p'speed,'supersonic'3p'speed'produces'Mul3ple'Pure'Tones'due'to'shock'noise)'–  Lower'fan'loading'and'3p'speed'should'reduce'noise'–  A&'fan'dominant'noise'signature'

•  Rotor/Stator''–  Increased'spacing'–'reduces'wake'impact'on'stators'–  Swept'Stators'–'larger'distance'between'rotor'and'stator'at'3p,'reduces'3p'vortex'

on'stators'–  Leaned'Stators'–'Orients'stators'more'in'line'with'swirl,'wake'angle'of'impact'less'

severe'

Fan'Noise'Reduc3on'Technologies'

Radial'Stators' Swept'Stators'

www.nasa.gov

Fan'Noise'Reduc3on'Technologies'(Cont.)'

•  Acous3c'Liners/Treatments'–  Usually'used'on'inner'duct'of'nacelle,'also'inner'hub'loca3ons'–  Other'loca3ons'inves3gated'such'as'a&'spli;er'–  Over'the'Rotor'Treatment'–  So&/Treated'Stator'Vanes'

•  Fan'Trailing'Edge'Blowing'–  Fills'in'wakes'produced'by'blades'lowering'fan'stator'interac3on'

34

www.nasa.gov

NASA/P&W'Fan'1'Liner'and'Fan'2'Test'Objec3ve:''

•  Acous3c'performance'of'various'liner'designs'•  Validate'noise'dependence'on'3p'speed'•  Determine'noise'of'advanced'casing'treatment'

used'to'increase'stall'margin'Approach:'

•  Test'combina3ons'of'bulk,'SDOF,'DDOF'liners'in'inlet,'mid,'and'a&'loca3ons'of'Pra;'ADP'Fan'1'

•  Test'lower'3p'speed'Fan'2'while'keeping'pressure'ra3o'as'Fan'1'

Results:'•  Full'DDOF'liner'set'showed'addi3onal'noise'

a;enua3on'compared'to'very'effec3ve'1995'Baseline'liner'

•  Fan'2'showed'limit'of'reduced'3p'speed/higher'loading'due'to'increase'in'noise'rela3ve'to'Fan'1'

•  Advanced'casing'treatment'showed'no'acous3c'penalty'while'increasing'stall'margin'

•  Develop'acous3c''''''database'for'ultraIhigh'''''bypass'ra3o'turbofan''''''model'

35

!

Max'Flow'Advanced'Casing'Treatment'

ADP'Liner'Loca3ons'

www.nasa.gov

A&'Duct'Treated'Spli;er'Objec3ve:''

•  Reduce'a&'fan'noise'•  Keep'performance'losses'to'minimum'

Approach:'•  Design'and'test'a&'acous3cally'treated'

spli;er'on'Pra;'ADP'model'in'9x15'LSWT'Results:'

•  Trailing'edge'of'spli;er'must'be'kept'thin'to'eliminate'Strouhal'shedding'tones'

•  Spli;er'tuned'to'17'kHz'model'scale'to'a;enuate'highest'annoyance'noise'

•  Spli;er'did'not'show'expected'noise'reduc3on'possibly'due'to'tunnel'background'noise'or'moun3ng'method'

•  Sta3c'test'did'show'spli;er'provided'a;enua3on'at'design'frequency'

•  Performance'loss'kept'to'1%'of'thrust'and'was'primarily'due'to'skin'fric3on'

•  Added'technology'such'as'microIblowing'could'reduce'skin'fric3on'

36

Black - Hard wall Nacelle Red - Treated Nacelle (DDOF) Blue - Treated Nacelle with Treated Splitter '

ADP Takeoff - 136 degrees '

A&''Spli;er'

kHz'

SPL,'dB'

www.nasa.gov

Over'the'Rotor'–'So&'Vane'Concepts'Objec3ve:'•  Use'treatment'over'the'rotor'to'reduce'

rotor'alone'noise'•  Reduce'rotor/stator'noise'at'source'

using'so&'vanes'

Conclusions'•  OTR'treatment'not'effec3ve'in'reducing'noise'

unlike'other'previous'tests'had'shown'•  So&'Vanes'showed'PWL'reduc3ons'on'the'

order'of'1'dB'rela3ve'to'hard'vanes'for'certain'sha&'speeds'

Over'the'Rotor'Treatment' So&'Vanes'

Approach:'•  Design'and'Test'concepts'on'turbofan'''''''model'in'9x15'LSWT'

37

www.nasa.gov

Fan'Trailing'Edge'Blowing'

Objec3ve:'Characterize'aero/acous3c'performance'of'Fan'Trailing'Edge'Blowing'at'moderate'TRL''Approach:'Design'and'test'representa3ve'fans'in'low'speed'test'rig'and'the'9x15'LSWT''Outcome:''•  Tones'and'broadband'impacted'by'TEB;'

@'takeoff'II'2BPF,'I5dB;'3BPF,'I1dB;'4BPF'+.5'dB''

•  Thrust'slightly'higher'for'TEB'(9x15)'•  TEB'efficiency'94.4%'vs.'95.6%''baseline'

(9x15)'•  2%'blowing'rate'op3mum,'about'2db'

OASPL'noise'reduc3on'rela3ve'to'baseline'across'spectrum'

38

OAS

PL,'dB'

%'speed'Fite,'Woodward,'Envia,'Sutliff,'Podboy,'Jeracki,'Heidelberg,'John'Gazzaniga'

www.nasa.gov

Open'Rotor'Test'Entry'

Objec3ve:'Reduce'counter'rota3ng'open'rotor'noise'using'advanced'blade'designs'Approach:'Test'blade'design'concepts'in'9x15'LSWT'on'open'rotor'drive'rig'Outcome:''•  Test'of'Baseline'and'mul3ple'advanced'

blade'sets'•  Angle'of'A;ack'effects'•  Pylon'wake'noise'characteriza3on'•  Data'used'for'system'studies'of'aircra&'

noise'comparison'versus'ducted'engines'•  Obtained'large'database'of'open'rotor'

blade'acous3cs'for'pitch'angle,'angle'of'a;ack,'pylon'wake'

39

www.nasa.gov

Rotor'Alone'Nacelle'System'Objec&ve(•  Iden3fy'and'characterize'isolated'rotor'noise'sources'Approach(•  Develop'propulsor'simulator'that'eliminates'internal'

structures'and'isolates'rotor'within'nacelle'while'maintaining'opera3ng'characteris3cs'and'performance'

Outcome(•  New'test'technique'successfully'developed'and'tested'•  Fan'3p'clearance'held'to'0.005”'with'ac3ve'nacelle'

posi3oning'system;'fan'performance'maintained'•  Isolated'rotor'noise'sources'iden3fied'and'characterized'

40

SDT'Fan'Model'

www.nasa.gov

Rota3ng'Rake'

108

64

204

0322416

8

0-8

-16

-24

-32

-40

125120115110105100

95

PWL (dB)

PWL (dB)

Circumferential Mode (m-order)Rad

ial Mo

de (n-

order)

95

100

105

110

115

120

125

41

•  Extensive'fan'noise'database'for'a'variety'of'fans'covering'a'full'range'of'fan'pressure'ra3os'and'3p'speeds.'

•  Includes'noise'data'from'research'fans,'prototype'fans,'and'produc3on'engines.''

• Only'combined'inIduct'and'farfield'noise'database'for'low'speed'fans.'

SIGNIFICANCE:(The(Rota3ng'Rake'is'a'oneIofIaIkind'measurement'system'that'provides'a'complete'map'of'turbofan'duct'modes'(magnitude'&'phase).''This'measurement'system'has'contributed'to'development'of'engine'noise'reduc3on'technology.''

www.nasa.gov

Phased'Array'Measurements'

42

Experiment'

Simula3on'

Used'to'locate'noise'sources,'relies'heavily'on'tailored'data''processing'techniques,'e.g.'beamforming'

www.nasa.gov 43'

Ques3ons?'