Impact of Air Injection on Jet NoiseImpact of Air

Impact of Air Injection on Jet NoiseImpact of Air Injection on Jet Noise

Brenda Henderson and Tom NorumNASA Langley Research Center

Fall Acoustics Technical Working GroupDecember 4 – 5, 2007

Cleveland, OH

Objective

D t i i t f fl idi hDetermine impact of core fluidic chevrons on noise produced by dual stream jets

•Broadband shock noise - supersonic

Mi i i b i d i•Mixing noise – subsonic and supersonic

NATR

2

National Aeronautics and Space Administration

Jet Noise Sources

Fine Grain Turbulence

Large Scale Turbulence (Mach Wave

Broadband

Shock Noise Mixing Noise

(Mach Wave Emission)

Screech

• Mixing noise• Mach wave radiation

Crackle• Shock associated noise

BroadbandBroadbandDiscrete

• STOVL noise/tones Mach WavesCourtesy of D. Papamoschou

3


NASA Langley (LSAWT)

Low Speed Aeroacoustics Wind Tunnel

4


Jet Engine Simulator (JES)

5


Generation II Fluidic ChevronsAir Supply

Pylon

Slotted core no le

Fan Nozzle

Slotted core nozzle

Fluidic Chevron Core Nozzle

N l d i th lt f t hi b t NASA L l

6


Nozzle design was the result of a partnership between NASA Langley Research Center and Goodrich Aerostructures under SAA1-561

Generation III Fluidic Chevrons

• Core fluidic chevron nozzlenozzle

• 8 injectors– 4 pairs independently p p y

controlled• No common plenum

7


Fluidic Chevron Nozzles

BPR 5

8IFan Flow

Core Flow Injection Flow

6I 8I

Gen II Gen IIILine 1Line 2Line 2Line 3Line 4

Three Air Injection Nozzles

122o Pylon Angle

Three Air Injection Nozzles• 6I steep injection• 6I shallow injection

8


• 8I steep injection– azimuthal controlMicrophone

Chevron Mixing Enhancement

• Enhanced mixing shortens potential core and reduces

9


Enhanced mixing shortens potential core and reduces volume of acoustic sources

Characteristics of Fluidic ChevronsX/Dc = 8

Tt, K

Baseline

θ = 90oTakeoff

Mach 0.28

8IS

PL

(dB

)

5 dB

θ 90

8IFluidic Chevron - Generation IIMechanical ChevronBaseline

6I80 10 100 1000 10000

Frequency (Hz)

10


Experiments

NPRc TTRc

1.93 12 04 1

Single Stream Experiments2.04 12.17 12.30 2.5

• Fan stream operated at tunnel conditions

Dual Stream Experiments

NPRc TTRc NPRf TTRf

1.56 2.66 1.75 1.161.61 2.13 2.23 1.051.82 2.13 2.23 1.05 Dual Stream Experiments2.04 2.39 2.23 1.051.61 2.26 2.35 1.171.82 2.26 2.35 1.172.04 2.39 2.35 1.172.17 2.46 2.35 1.172.04 2.39 2.45 1.042.17 2.46 2.5 1.05

11


Free-stream Mach number = 0.10

Single Stream Resultsg

Baseline90

Baseline nozzle and injection nozzles with70

80

B)

θ = 61oShock Noise

injection nozzles with IPR = 1.0 have similar noise characteristics50

60

SP

L (d

B

BaselineGen II Steep Injector, IPR = 1.0Gen III, IPR = 1.0

30

40

100 1000 10000 100000Frequency (Hz)

,

95θ 148

NPR = 2 17

Frequency (Hz)

75

85B

)θ = 148o

NPRc = 2.17

55

65

SP

L (d

B

BaselineGen II Steep Injector, IPR = 1.0Gen III, IPR = 1.0

13

National Aeronautics and Space Administration35

45

100 1000 10000 100000Frequency (Hz)

Effect of Increasing NPRc90

70

80

90

) Well defined shock noise

θ = 61o

50

60

SP

L (d

B

NPRc = 1.93NPRc = 2 04

Well defined shock noise peak at NPRc = 2.17

30

40

100 1000 10000 100000

NPRc 2.04NPRc = 2.17

95Frequency (Hz)

75

85

95

B)

θ = 148o

45

55

65

SP

L (d

B

NPRc = 1.93NPRc = 2.04NPRc = 2 17

14


35

45

100 1000 10000 100000Frequency (Hz)

NPRc = 2.17

90

Injection at Low Supersonic Speeds

70

80

90

)

• Injector noise is is not suppressed

θ = 61o

50

60

SP

L (d

B)

IPR = 1.0IPR = 2.0IPR = 4.0

• Increases in IPR produce reductions in mixing noise near peak

30

40

100 1000 10000 100000F (H )

95

mixing noise near peak jet noise angle

Frequency (Hz)

75

85B

)θ = 148o

NPRc = 1.93

45

55

65

SP

L (d

IPR = 1.0IPR = 2.0IPR = 4.0

15


35

45

100 1000 10000 100000Frequency (Hz)

Injection for Well-Defined Shock Noise90

70

80

90

Increases in IPR produce red ctions in shock noise

θ = 61o

50

60

SP

L (d

B)

IPR = 1.0IPR = 2 0

reductions in shock noise and mixing noise

30

40

100 1000 10000 100000F (H )

IPR = 2.0IPR = 4.0

95Frequency (Hz)

75

85

95

B)

θ = 148o

NPRc = 2.17

45

55

65

SP

L (d

B

IPR = 1.0IPR = 2.0

16


35

45

100 1000 10000 100000Frequency (Hz)

0IPR = 4.0

Azimuthal Control for Shock Noise90

70

80

90

B)

θ = 61oSignificant shock noise reduction can be achieved

50

60

SP

L (d

B

IPR All = 1.0IPR All = 4 0

with injection near pylon

%1121injectionm&

30

40

100 1000 10000 100000Frequency (Hz)

IPR All 4.0IPR 1,2 = 4.0

95

%1.12,1 =core

injection

m&

q y ( )

75

85

95

B)

θ = 148oNPRc = 2.17

All

55

65

SP

L (d

B

IPR All = 1.0IPR All = 4.0IPR 1,2 = 4.0

1,2 All

17


45

100 1000 10000 100000Frequency (Hz)

Impact of Injection on Sideline Directivity

110

106

108

dB)

104

106

OA

SP

L (d

102

O IPR = 1.0IPR = 2.0IPR = 4.0

10045 60 75 90 105 120 135 150

Angle (deg)

18


Angle (deg)

Dual Stream ResultsDual Stream Results

Injection at Subsonic Core and Fan Speeds90

70

80

90

B)

θ = 90o Mixing noise reduction can be achieved with injection near observation side of jet

50

60

70

SP

L (d

B

BackgroundIPR All = 2 3

%6.12,1 =injection

mm&

&near observation side of jet

40

50

100 1000 10000 100000Frequency (Hz)

IPR All = 2.3IPR 1,2,3 = 1.4 & IPR 4 = 2.3

110

corem

Frequency (Hz)

90

100dB

)

BackgroundIPR All = 2.3IPR 1,2,3 = 1.4 & IPR 4 = 2.3

NPRc = 1.56NPRf = 1.75

70

80SP

L (d θ = 148oAll4

20


60100 1000 10000 100000

Frequency (Hz)

75

Injection at Subsonic Core and Fan Speeds

55

65

75

B)

Injection produces mixing noise reduction at

θ = 90o

35

45

55

SP

L (d

B

BackgroundIPR All = 2.3

peak jet noise angle with slight increase in high frequency noise at 90o

25

35

10 100 1000 10000Frequency (Hz)

IPR All 2.3IPR 1,2,3 = 1.4 & IPR All = 2.3

90

frequency noise at 90

70

80B

)

BackgroundIPR All = 2.3IPR 1,2,3 = 1.4 & IPR 4 = 2.3

NPRc = 1.56NPRf = 1.75

50

60SP

L (d

B

θ = 148oNozzle IPR EPNL (EPNdB)

Injection Mass (% Core)

Baseline 90.4Air Injection All = 2.3 89.6 2.9Air Injection 1,2,3 = 1.4 & 4 = 2.3 89.4 1.6

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50

10 100 1000 10000Frequency (Hz)

Baseline Results at NPRf = 2.23100

80

90

100

)

Increasing NPRc• Decreases shock noise

θ = 61o

60

70

SP

L (d

B

NPRc = 1.61, NPRf = 2.23

NPRc = 1.82, NPRf = 2.23

Decreases shock noise peak

• Increases mixing noise

40

50

100 1000 10000 100000F (H )

NPRc = 2.04, NPRf = 2.23

110

near peak jet noise angle

Frequency (Hz)

90

100B

)θ = 148o

60

70

80

SP

L (d

NPRc = 1.61, NPRf = 2.23

NPRc = 1.82, NPRf = 2.23

22


50

60

100 1000 10000 100000Frequency (Hz)

NPRc = 2.04, NPRf = 2.23

Injection at Subsonic Core Speeds100

80

90

100

) Increasing IPR decreases

θ = 61o

60

70

SP

L (d

B)

IPR = 1.0IPR = 2.5

gshock peak

110

40

50

100 1000 10000 100000F (H )

IPR 2.5IPR = 4.0

θ 148

90

100B

)Frequency (Hz)

NPR = 1 61

θ = 148o

60

70

80

SP

L (d

IPR = 1.0IPR = 2.5IPR = 4.0

NPRc = 1.61

NPRf = 2.23

23


50

60

100 1000 10000 100000Frequency (Hz)

Azimuthal Control at Subsonic Core Speeds100

No noise reduction with Gen III nozzle due to low80

90

100

B)

θ = 61o

Gen III nozzle due to low mass flow rates or steeper injectors60

70

SP

L (d

B


40

50

100 1000 10000 100000Frequency (Hz)

,

110

NPRc = 1.61NPRf = 2.23

q y ( )

90

100

110

B)

θ = 148o

All

70

80

SP

L (d

B


1,2 All

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National Aeronautics and Space Administration 50

60

100 1000 10000 100000Frequency (Hz)

Injection at Supersonic Core Speeds100

80

90

100

)

θ = 61o

Increases in IPR produce

60

70

SP

L (d

B

IPR = 1.0IPR = 2.5IPR = 4.0

preductions in noise near peak jet noise angle

40

50

100 1000 10000 100000F (H )

110Frequency (Hz)

90

100B

)θ = 148o

60

70

80

SP

L (d

IPR = 1.0IPR = 2.5IPR = 4.0

NPRc = 2.04

NPRf = 2.23

25


50

60

100 1000 10000 100000Frequency (hz)

Injection at Subsonic Core Speeds100

80

90

100

)

θ = 61oIncreasing IPR• Has no impact on

60

70

SP

L (d

B)

IPR = 1.0IPR = 4.0IPR = 5.0

Has no impact on broadband shock noise

• Slightly reduces noise at

40

50

100 1000 10000 100000F (H )

120

peak jet noise angle

Frequency (Hz)

100

110B

)θ = 148o

70

80

90

SP

L (d

IPR = 1.0IPR = 4.0IPR = 5.0

NPRc = 1.82

NPRf = 2.35

26


60

70

100 1000 10000 100000Frequency (Hz)

Points of Discussion

• Injection impacts shock structure and stream j pdisturbances through enhanced mixing

– May impact constructive interferenceMay impact constructive interference between acoustic sources

• High fan pressures may inhibit mixing produced by core injectorsp y j

– Fan stream injection may be required for better noise reduction

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better noise reduction

Future Plans

• Modification of Gen II nozzles to allow for some azimuthal control

• Will allow for higher mass flow ratesWill allow for higher mass flow rates• Will allow for shallower injection angles

Fl fi ld t d i 2008• Flow field study – spring, 2008• CFD analysis of flow

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Conclusions

Injection can reduce well defined• Injection can reduce well-defined shock noise

• Injection reduces mixing noise near peak jet noise anglepeak jet noise angle

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Documents

Impact of Air Injection on Jet NoiseImpact of Air