Technologies for TurbofanNoise Reduction
Dennis HuffNASA Glenn Research Center
Cleveland, OhioU.S.A.
Special thanks to Edmane Envia, James Bridges and Mike Jones
presented at10th AIAA/CEAS Aeroacoustics Conference
Manchester, United KingdomMay 11, 2004
777-200
A330-300
MD-90-30
MD-11
A320-200747-400
A300-600R
767-300ERA310-300757-200
MD-87MD-82
B-747-300A300B4-620
A310-222
MD-80
B-747-200
B-747-SPDC-10-40
B-747-200A300
B-747-200B-747-100
B-737-200B-737-200
B-727-200DC9-10
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 NoiseLevel Relativeto Stage 3(EPNdB)
HistoryJT3D, JT8D, JT9D,CF6,CFM56
CurrentJT8D-200,PW2000,PW4000,V2500,GE90,PW6000
Future Goals
Stage 2
Stage 3
Stage 4
Advanced Subsonic Technology (AST) Noise Reduction Program Goal of 5 dB
Averagein Service
New Technology Enables AircraftTo Meet Future Requirements
Quiet Aircraft Technology (QAT) Program Goal (additional 5 dB)
Fleet Noise Reduction,
EPNdB
According to a document from the U.S. Environmental Protection Agency (EPA) published in the 1970’s, 55 LDN is the outdoor noise exposure level "requisite to protect the public health and welfare with an adequate margin of safety". The phrase "health and welfare" is defined as "complete physical, mental and social well-being and not merely the absence of disease and infirmity".
0
5
10
15
20
25
30
35
40
45
50
IAD DFW BOS CVG LAX MCO SFO ORD PIT DTW MSP ATL EWR JFK SEA LGA ZRH
Aircraft Fleet Noise Reduction Needed For55 LDN Noise Contours Within Airport Boundaries
Analysis by Don Garber, NASA Langley, using NoiseMap
(PW8000)
Pratt & Whitney’s PW8000 Turbofan Engine(Conceptual)
FanStator
Compressor
Combustor
Turbine
Exhaust
Inlet
Engine Noise Reduction Technologies
Higher Bypass Ratio Swept/Leaned StatorsScarf Inlets
Act ive Vanes Installed on the NASA,Glenn Act ive noise Cont rol Fan
Rotor Blade
Stator Vane
Active Noise ControlNoise PredictionChevron Nozzles
Forward-Swept Fans
OUTLINE
• Source Diagnostics Tests
• Fan Noise
• Jet Noise
• Static Engine Tests & Flight Validation
• Future Directions
Far-field Acoustics
Flow Diagnostics
Small Hot Jet Acoustic Rig (SHJAR)
Bridges & Wernet (AIAA Paper 2003-3130)Bridges & Wernet (AIAA Paper 2003-3130)
Koch, Bridges, Brown & Khavaran(INCE NOISE-CON 2003)
Koch, Bridges, Brown & Khavaran(INCE NOISE-CON 2003)
• Provide reliable data base for experimental and analytical comparisons• Cover wide range of subsonic and supersonic conditions (Tanna data)
0.5
1.0
1.5
2.0
2.5
3.0
3.50.0 0.5 1.0 1.5 2.0 2.5 3.0
Vjet /C amb
2T2C PIV
PArray
FF acoustics
M=2
M=1
MWE
Ts/Tamb
Jet Noise Baseline Data For CFD/CAA Validation
• Objective: Turbulent flow statistics 0
3
0 1 2Vjet/Camb
U/Uj
V/Uj
TKE/Uj2
v2/u2
L11/Dj
L11/ L12
τ1Uj /Dj
τ2/τ1
Ts/Tamb
Jet Noise Baseline Data For CFD/CAA Validation
Bridges & Wernet (AIAA Paper 2002-2484)Bridges & Wernet (AIAA Paper 2002-2484)
Fan Source Diagnostics Test (SDT)
Rotor & Stator Rotor-Alone
Acoustic Barrier Wall
Top View Schematic of NASA’s 9’ x 15’Low-Speed Wind Tunnel
ApproachComprehensive Aero-Acoustic TestingAdvanced DiagnosticsSource Separation
Inlet vs. exhauststage vs. rotor-alone
Testbed: SDT Fan Rig
Inlet BL Surveys (HW)
Tip Flow Surveys (LDV)
Shock Location Surveys (LDV) Unsteady Pressure Surveys
Wake Surveys (LDV)2-Point Correlation Surveys (HW)
Duct Wall Pressure Surveys Rotating Rake Microphone Surveys
Turbulence Surveys (PIV)
Tested 2 Fans, 3 Outlet Guide Vanes and Rotor-Alone Configurations at Multiple Fan Tip Speeds
Nozzle Exit Surveys (LDV)
Fan Source Diagnostics Test Summary
Traversing Microphone Farfield Surveys
Rotor-Alone Fan Noise
Computation of Rotor Wake Turbulence NoiseNallasamy et. al (AIAA Paper 2002-2489)
LDV Measured Flow Field ResultsPodboy et. al (AIAA Paper 2002-2431)
Vane Unsteady Pressure Results Envia (AIAA Paper 2002-2430)
Wall Measured Circumferential Array Mode ResultsPremo & Joppa (AIAA Paper 2002-2429)
Tone Modal Structure ResultsHeidelberg (AIAA Paper 2002-2428)
Farfield Acoustic ResultsWoodward et. al (AIAA Paper 2002-2427)
Rotor Alone Aerodynamic Performance ResultsHughes et. al (AIAA Paper 2002-2426)
Fan Source Diagnostics Test - References
Power (dB)Mode: (m,n)Power (dB)Mode: (m,n)
Total
(-4,1)
(-4,0)
Cut-On Stator (1xBPF)
114 112
102 98
101 103
100 97
113 111
Cut-Off Stator (2xBPF)
Total
(-10,3)
(-10,2)
(-10,1)
(-10,0)
125 125
120 120
124 124
Exhaust Tone Levels: Prediction Data*Cut-Off Stator
MethodologyFan Wake Description: Steady RANSOGV Acoustic Response: Linearized Euler
Verdon et al. (NASA/CR-2001-210713)Verdon et al. (NASA/CR-2001-210713)
Cut-On Stator
* Data includes a recently discovered 3 dB correction
Fan Tone Noise Prediction (Frequency Domain)
Harmonic content of unsteady pressure (only 9 passages shown)
1xBPF 2xBPF 3xBPF
m =
-10
m =
-10
m =
+12
m =
-42
Cut
-off
Cut
-off
Re (p’)
+
-
Computational Aeroacoustics for Fan Noise Prediction (Time-Domain)
MethodologyTime-Accurate, Non-linear & Inviscid SimulationValidated in 2D. Extension to 3D is Underway
Nallasamy et al. (AIAA Paper 2003-3134)Nallasamy et al. (AIAA Paper 2003-3134)
Fan Broadband Noise Prediction
Fan Wake Turbulence Description: Steady RANS
OGV Acoustic Response: Strip-wise lift response (2D cascade)Classical duct acoustics (3D)
Nallasamy et al. (AIAA Paper 2002-2489)Nallasamy et al. (AIAA Paper 2002-2489)Methodology
Inlet and Exhaust PWL at Approach Condition (Stator Contribution Only)Data includes both coherent and broadband, theory only includes broadband
Accounts for realistic geometries
Uses CFD to achieve higher quality acoustic predictions
Couples with source codes like LINFLUX or TFaNS
Fan Noise Duct PropagationCDUCT-LaRC Code
Scarf Inlets
Fan Noise Reduction
Low Count Reduces Broadband NoiseSweep Minimizes BPF Tone Penalty
Low-Count Swept OGV
blade internal passages
blowing air
Trailing Edge BlowingFill-In the Rotor Wake
reduces tone noisereduces broadband noise
Woodward et al. (AIAA Paper 2002-2427)Woodward et al. (AIAA Paper 2002-2427)Sutliff et al. (International J. of Aeroacoustics,
Vol. 1, No. 3, 2002)Sutliff et al. (International J. of Aeroacoustics,
Vol. 1, No. 3, 2002)
Virginia Polytechnic Institute Herschel-Quincke (HQ) TubesNASA Advanced Noise Control Fan (ANCF)
Fan Noise Reduction
Act ive Vanes Installed on the NASA,Glenn Act ive noise Cont rol Fan
Rotor Blade
Stator Vane
NASA/BBN Active Noise Control Fan Test
Fan Noise Reduction
Jet Noise Reduction – Flight Tests
Chevron Benefit Comparison - Perceived Noise Level (PNL)
Model Scale Tests Learjet Flight Data
Model Scale Versus Flight Tests
Brown & Bridges (NASA TM 2003-212732)Brown & Bridges (NASA TM 2003-212732)
B = 22
&
B = 24
V = 28
Scarf Inlet
Active-Passive Liner Fan Blade # Change andLow Number/Cuton FEGV
Advanced PW Fan Case Treatment
Treatment
Treated Primary Nozzle
Pratt & Whitney PW4098 Engine Test
Variable Nozzle Chevron Nozzle Scarf Inlet
Honeywell Flight Demonstrationof Noise Reduction Concepts
1996 Wright Brothers Lectureship in Aeronauticsby Philip M. Condit, The Boeing Company, October 22, 1996
“Ultra-high-bypass-ratio engines [to] reduce fuel consumption,engine maintenance, and community noise. It might be possible to reduce community noise by 10 dB, thus making airplane noise a non-issue at airports.”
Propulsion System•Geared Fan Engines
Aerodynamics•Slotted Cruise Airfoil•Natural Laminar Flow
Flight Systems & Flight Deck•Fly-by-wire
Structure & Materials•Low Temperature Graphite Composite:
•Fuselage•Wing•Empennage
•Cast Aluminum Doors
2016 Subsonic Airplane
Dual-Fan Engine Concept On Blended Wing Body
Backup Charts
0
50
100
150
200
250
300
350
400
1960 1970 1980 1990 2000Year
Num
ber o
f Res
trict
ions
Number of Airports in Database: 591Noise Restrictions Continue to Grow
Noise AbatementProcedures
Curfews
Charges
Levels
Source: David H. Reed, Manager of Noise Technology, Boeing Commercial Airplane, 1998
Engine Noise Reduction for Large Quad - Sideline Results From P&W Study
88.6
72
94.5
87
96.598.9
84.6
72
93.4
87
94.6
97.5
84.6
72
92.2
87
94.697.0
84.6
81
88
83
80
90.2
84.6
81
86.1
81.579.4
88.8
84.6
81
84.1
7879.35
87.3
65
70
75
80
85
90
95
100
105
Airframe Combustor Fan Exhaust Fan Inlet Jet **Engine Sum
EPNd
B
P&W '92 Tech. BPR=5+Source Red. BPR=5+Source+Nac.ADP Cycle Only ADP+Source ADP+Source+Nac.
Engine Noise Reduction for a Large Quad AircraftResults From Pratt & Whitney Study
Approach Power
Engine Noise Reduction for Large Quad - Approach Results From P&W Study
98.1
76
99 100
89
102.7
94.1
76
96.7
99.65
88.75
101.7
94.1
76
94.596.1
88.75
98.9
94.1
83
93 93
73
96.294.1
83
89.7 89.8
73
93.294.1
83
89.5
85.5
73
91.7
65
70
75
80
85
90
95
100
105
Airframe Combustor Fan Exhaust Fan Inlet Jet **Engine Sum
EPNd
B
P&W '92 Tech. BPR=5+Source Red. BPR=5+Source+Nac.ADP Cycle Only ADP+Source ADP+Source+Nac.
Engine Noise Reduction for a Large Quad AircraftResults From Pratt & Whitney Study
Sideline Power
Stage 31992 AST Baseline
1996 UHB Technology ( “Fan 1”)
2000 UHB Technology(“Fan 3”)
Fan Stage Pressure Ratio
Fan Tip Speed (fps)
Ave
rage
EPN
dBR
educ
tion
3
7
4
Evolution of Ultra High Bypass Turbofan Noise ReductionBased On NASA/P&W Advanced Ducted Propulsor Model Tests
Scaled to 130” Diameter Fan, Large Quad Airplane
1220 dB Goal
480 840
1.08 1.28
Increase Bypass Ratio
Improved LowNoise Design
“Fan 1”
“Fan 3”
Takeoff PowerApproach Power
1997 NASA/GE/P&W Separate Flow Nozzle Test
Flow Field Measurements
Jet Noise Reduction Research
Nozzles of the Future
12-Lobe MixerSplitter Nozzle
L L u u2 1 22
120 8 0 7/ . , / .= =
Isotropy:
Anisotropy:
L L u u2 1 22
121 1/ , /= =
MODIFIED “MGB” CODE, now called “MGBK”Combines CFD solutions with modelingof noise sources to predict far-field acoustics• Small-scale turbulence noise • External mixing noise only• Accounts for both self and shear noise• Non-isotropic turbulence• Can be extended to a 3D geometry
(assumes flow is locally axisymmetric)
Jet Noise Prediction
First Integrated Fan Noise Source and Propagation Prediction Code (1994)
Baseline Swept Stators Swept/Leaned Stators
Fan Noise Reduction Research1996 NASA/Allison Swept & Leaned Stator Test
Northrop Grumman HybridActive/Passive Liner Installedin the NASA ADP Fan Rig at theNASA LeRC 9’x15’ Wind Tunnel• Superior Performance Relative to Conventional
Uniform Passive Liners Over Extended Fan Speeds• 3 to 10 dB Attenuation Increase Over Uniform Passive
Liners for ADP Fan over the Speed Range of 5200 to 6000 RPM
UniformPassive
Two SegmentPassive
Hybrid Active/Passive
Near Grazing Incidence Fan Noise; Modest Overall Attenuation.
Initial Segment Scatters Modes into Higher Order Radial Modes. Limited Bandwidth ofAttenuation SinceLiner is Efficient onlynear Design RPM.
Initial Active ControlSegment Compensatesfor Changing ParametersResulting from ModeMixture Variations withFan Speed. High Band-width of Attenuation.
Fan Noise Reduction Research1996 NASA/Northrop Grumman Active Noise Control Fan Test
(3-layers) series parallelsingle layer
L
Series elements(3 layers)
Parallel element(single layer)
Combined(series & parallel)
Best Performing Liner Configurations
Stator Vanes (28) 4 ft Fan (16 Blades)
ICD
Rotating Rake mode measurements
inlet & exit plane
Control Microphonesfore & aft spool sections (1 6 each row, 96 t ot al)
NASA 48" ANC FAN with BBN Act ive Vanes
PZT (THUNDER) Act uators 6 per vane, 4 Channels of Control
Fan Noise Reduction Research1998 NASA/BBN Active Noise Control Fan Test
Honeywell TFE731-60 Engine Test
TFE731-60 Engine withInflow Control Device (ICD)
Rotating Microphone
Scarfed Inlet
Chevron Nozzles
Variable Area Nozzle
