Technologies for Turbofan Noise Reduction Dennis Huff NASA Glenn Research Center Cleveland, Ohio U.S.A. Special thanks to Edmane Envia, James Bridges and Mike Jones presented at 10 th AIAA/CEAS Aeroacoustics Conference Manchester, United Kingdom May 11, 2004
39
Embed
Technologies for Turbofan Noise Reduction · PDF fileTechnologies for Turbofan Noise Reduction Dennis Huff NASA Glenn Research Center Cleveland, Ohio ... BPR=5+Source+Nac. ADP Cycle
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Technologies for TurbofanNoise Reduction
Dennis HuffNASA Glenn Research Center
Cleveland, OhioU.S.A.
Special thanks to Edmane Envia, James Bridges and Mike Jones
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
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.”
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