Transcript Siemens Wind Power

Siemens Wind Power
Siemens Power Generation 2005. All Rights Reserved
Siemens Power Generation 2005. All Rights Reserved
EWEC 2006
Noise Optimization of a Multi-Megawatt Wind Turbine
 Aero-acoustic noise measurements of an SWT-2.3-93
 Aero-acoustic noise calculations of an SWT-2.3-93 and comparison
with measurements
 Posibilities for low-noise power production
 Conclusions
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Aero-acoustic noise meassurements of an SWT-2.3-93
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Aerial view of Høvsøre National Test-site for large
prototype wind turbines
SWT-2.3-93
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Aero-acoustic noise meassurements of an SWT-2.3-93
Turbine
Turbine rated power:
2300kW
Blade length:
45m
Control system:
Variable speed, pitch control
Tower height:
80m
Acoustic noise recording and processing
Hardware:
Brüel & Kjær
Software:
Brüel & Kjær (Pulse)
Measurement location:
On ground 100m downwind of rotor
Temporal resolution of averages:
10s bins
Frequency resolution of averages:
1/12 octave spectra
Turbine data logging (pow, pitch, rpm, wind etc):
Full inclusion in noise recording
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Aero-acoustic noise meassurements of an SWT-2.3-93
The acoustic data was recorded during 2 consecutive days in may 2006.
Approximately 11hrs of data
3D data matrix to populate with recordings
1st dimension:
Wind:
4 to 12 m/s
2nd dimension:
Pitch:
-4 to 12 degrees
3rd dimension:
Rotor speed:
9-18rpm
Post-processing details of 10s binned 1/12 octave spectra
Background noise subtraction
High frequency bird noise identification and subtraction
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Aero-acoustic noise meassurements of an SWT-2.3-93
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Measured Soundpower levels for all 10s binned spectra
110
105
soundpower [dB]
100
95
-3 to -1 deg pitch, 4-8 m/s wind
-3 to -1 deg pitch, 8-12 m/s wind
-1 to 1 deg pitch, 4-8 m/s wind
-1 to 1 deg pitch, 8-12 m/s wind
1 to 3 deg pitch, 0-4 m/s wind
1 to 3 deg pitch, 4-8 m/s wind
3 to 5 deg pitch, 0-4 m/s wind
3 to 5 deg pitch, 4-8 m/s wind
3 to 5 deg pitch, 8-12 m/s wind
5 to 7 deg pitch, 0-4 m/s wind
5 to 7 deg pitch, 4-8 m/s wind
7 to 9 deg pitch, 0-4 m/s wind
7 to 9 deg pitch, 4-8 m/s wind
9 to 11 deg pitch, 0-4 m/s wind
9 to 11 deg pitch, 4-8 m/s wind
11 to 13 deg pitch, 0-4 m/s wind
11 to 13 deg pitch, 4-8 m/s wind
90
85
80
75
70
4
6
8
10
12
rpm
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16
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Note: High rotor-speed sensitivity, less pitch sensitivity and very litle wind sensitivity on acoustics
Measured (red) Soundpower contours [dBa]
10 7
10 8
106
10 4
10 3
10 2
92
0
10
12
13
14
15
16
17
108
10 7
10 6
10 5
10 4
10 3
99
10 2
98
10
1
97
10 1
10 0
99
95
93
94
pitch [deg]
87
11
108
10
10 7
9
95
96
90 1
9
92
-2
94
105
0
93
10 6
2
10 5
10 1
10 0
99
98
97
91
90
89
88
86
96
6
4
10 4
95
94
93
87
8
10 3
10 2
92
10
-4
1
10
98
97
96
91
90
89
88
12
18
rpm
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Aero-acoustic noise meassurements of an SWT-2.3-93
Aero-acoustic noise calculations of an SWT-2.3-93
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The aero-acoustic source model
5 types of noise:
• TE bluntness vortex shedding (BPM model)
• Laminar boundary layer TE vortex shedding (BPM model)
• Turbulent boundary layer TE (BPM model)
• Turbulent boundary layer separation (BPM model)
• Turbulent inflow (Amiet model with simplified Guidati)
Model implementation:
NAFNoise (Moriarty, NREL)
Boundary layer inputs:
XFoil (Drela, MIT).
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Aero-acoustic noise calculations of an SWT-2.3-93
The aero-acoustic propagation model
Modifications to simple radial propagation from a point source:
• Rotor distributed sources
• Directivity (blade acts an acoustic dipole)
• Air absorption
• Atmospheric shear correction
• Doppler shift
Absent modifications:
• Non-flat terrain
• Multiple sound ray reflections due to shear
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Aero-acoustic noise calculations of an SWT-2.3-93
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Superposition of calculated soundpower contours at 8m/s
Measured (red) and calculated (black) Soundpower contours [dBa]
10 6
98
12
13
10 8
10 7
106
104
10 4
103
10
5
14
15
10 8
16
17
108
10 6
7
10
10 7
4
10
4
10
10 5
5
10
6
10
10 4
10 2
11
10130 1
10 0
10 0
99
95
94
3
10
10
6 10 3
10
1
98
10 3
95
92
97
10 2 102
98
99
94
97
92
91
93
pitch [deg]
87
93
1
10
102
3
949
10
10 5
9996
1
10
2
99 10100
105
97
96
9
10 1
0
10
95
95
9291
9089
-4
10 0
94
90 1
9
92
-2
99
97
93
98
0
98
96
94
2
97
91
90
89
88
86
4
96
6
101
100
95
96
94
8
93
87
90
108
10 7
10 6
10 4
10 3
1054
10
10 3
10 2
95
92
10
10 2
1
10
99
9898
97
96
91
90
89
88
12
18
rpm
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Aero-acoustic noise calculations of an SWT-2.3-93
Spectral comparisons at low rotor-speed:
wind = 5.2 m/s. pitch = 7.3 deg. rpm = 9.85
Measured: 89.6 dB(a). Calculated: 91.4 dB(a)
90
90
85
85
Sound Power [dB(a)]
Sound Power [dB(a)]
wind = 10 m/s. pitch = -2 deg. rpm = 9.75
Measured: 97.3 dB(a). Calculated: 91.9 dB(a)
total
80
75
70
separation
TBL
80
total
75
turbulent
inflow
pressure side
TBL
suction side
TBL
70
turbulent
inflow
65
2
10
3
10
1/3 octave frequencies [Hz]
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4
10
65
2
10
4
3
10
10
1/3 octave frequencies [Hz]
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Spectral comparisons at high rotor-speed:
wind = 11.6 m/s. pitch = 9.5 deg. rpm = 17.1
Measured: 106.7 dB(a). Calculated: 104.9 dB(a)
wind = 10.8 m/s. pitch = 1.5 deg. rpm = 17.1
Measured: 107.6 dB(a). Calculated: 107.3 dB(a)
100
100
total
90
turbulent
inflow
85
80
separation
pressure TBL
side
TBL
suction side
TBL
75
70
2
10
3
10
1/3 octave frequencies [Hz]
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total
95
Sound Power [dB(a)]
Sound Power [dB(a)]
95
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90
85
suction side
TBL
80
pressure side
TBL
75
4
10
70
turbulent
inflow
2
10
4
3
10
10
1/3 octave frequencies [Hz]
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Aero-acoustic noise calculations of an SWT-2.3-93
Siemens Power Generation 2005. All Rights Reserved
Posibilities for low-noise power production
Measured Soundpower contours [dBa] with superposed Power contours [kW] at 8m/s wind
13
14
75 0
80 0
82 5
16
108
0
85
5
82
5
0
5
707
80
720 0
5
7
7
17
18
10 7
5
87
10 6
10 5
104
15
90
0
90 0
103
10
1
10 0
108
10 6
10 5
85 0
87 5
10 2
97
98
57 5
62 5
65 0
10 7
96
85
0
4755 45 0
00
77 5
10 1
75 0
97
92
10 0
99
95
94
93
72
92 5
67
5
6
87 2 5
65
0
pitch [deg]
10 8
107
70 0
72 5
10 6
12
104
82 5
11
10 5
80 0
5
82
99
98
10 3
5
77
80 0
72 5
10
67 5
65 0
62 5
9
77 5
-2
10 4
95
96
60 0
-5-502 -5-5-567-06025
0-5-44 705
505
-1-1575
0
50 25 0
-2 5 -5 0
75
17155 0 12 5
20
25 0
2
0
25
44020
5
10 2
75 0
37 5
10 1
94
10 0
875
93
10 3
700
90 91
10 0
70 0
-3 -4 -04 2
75- -0 5
3 35
-2-02-22 5205 0
05
98
91
0
-4
90
89
88
2
86
4
60 0
97
6
40 0
42 5
92
87
8
52 5
0
55
-2 -3 0
75 0
96
37 5
10 2
1
10
99
93
50 25 0
-2 -5 -7 -1 -1
5
0 5
00 25
75
12
1715 0
5
5
25 0
222050
27 5
32 5
30 0
35 0
47 5 45 0
50 0
55 052 5
57 5
62 5
650
675
95
30
0
94
32 5
35 0
10
10
0
91
90
27
5
89
88
12
rpm
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Aero-acoustic low-noise analysis
Calculated noise curve for the SWT-2.3-93
110
Low-noise power production is aimed at the operation
point at 11m/s hub height wind.
105
Quick ‘n dirty gradient analysis
Pitch variation:
-1.05 dB/deg,
-0.2 %AEP/dB,
0.0 %flapload/dB
-0.5 %AEP/dB,
-1.5 %flapload/dB
maxRPM variation:
0.72 dB/rpm,
Soundpower [dB(a)
Max. sound emission at 11m/s, just before rated power is
reached.
100
95
90
Chord variation:
-0.03 dB/(%chord) 2.5 %AEP/dB,
28 %flapload/dB
85
Blade thickness variation:
80
-0.02 dB/(%thick),
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-8.4 %AEP/dB,
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4.5 %flapload/dB
4
6
8
10
12
14
16
Wind speed at hub height [m/s]
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Posibilities for low-noise power production
Conclusions and future work
 Turbulent boundary layer separation noise is qualitatively well reproduced by model, but is
overpredicted. Rotational 3D-effect that postpones stall might be part of the explanation.
 TE bluntness model overpredicts measurements by 5+ dBs, hence excluded.
 Turbulent boundary layer TE noise model fits measurements well.
 Turbulent inflow noise model generally fits measured low frequencies well.
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Acoustic model validation
Low-noise turbine operation
 Positive pitching (away from stall) is the primary handle according to model – however,
measurements indicate much less pitch sensitivity. Reduced RPM also reduces noise at a low
cost according to both model and measurements.
 Chord- and thickness-variations do not show significant impact on acoustics, and AEP- and/or
load-cost is significant.
 Every dB-favorable change has a cost, either on AEP or loads.
Overall the model can deliver accurate predictions, once the deficiencies (bluntness) and
weaknesses (separation noise) are identified. It will assist future blade design.
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Thank you for your
attention
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