402
P. Liu
measures can be conducted in it. D5 wind tunnel has a good flow field
quality and low background noise level, and its aerodynamic noise index
meets the design requirements (as shown in Table 6.1). The D5 aeroacoustic wind tunnel is composed of a test section, diffusion section, corner
section, power section, and stability section. The overall length, width, and
height of the wind tunnel are 25.58 m, 9.2 m, and 3.0 m. The section of
the test section is square, with a width of 1.0 m and a height of 1.0 m.
The length of the closed test section is 2.5 m, the length of the open test
section is 2.0 m, and the length of the air collector is 0.5 m. The test
section is open and closed. There is a full anechoic chamber of 7 m ×
6 m × 6 m surrounding the test section. When the wind tunnel runs in
an open-jet form, it is a typical aeroacoustic wind tunnel. Both conventional aerodynamic and acoustic tests can be conducted in the D5 wind
tunnel.
The center line of the wind tunnel test section is 2.0 m above the
ground. The wind tunnel structure is made of pure steel, and the thickness of the tunnel wall is 6 mm. In order to improve the main frequency
Table 6.1 Main aerodynamic and acoustic design indexes of D5 wind tunnel
The serial number
Project
1
Test section dimensions: length 2.5 m, width 1 m, height 1 m,
contraction ratio 9
2
Velocity of open test section: V 0 = 1.5−80 m/s
Velocity of closed test section: V 0 = 1.5−100 m/s
3
Turbulence in the test section: ε =
u 2
V 0 = 1 − 0.08%
4
Velocity instability of test section: <1%
5
Mean speed deviation of test section:V < 1%
6
Deviation Angle of air flow at space point:
α ≤ ±0.5 0 ;β ≤ ±0.5 0
Mean flow deflection angle: α ≤ ±0.1 0 ;β ≤ ±0.1 0
7
Axial static pressure gradient in the test section:
dp
dx
< 10 Pa/m
8
Microperforated plate silencer is used in the fan section of
the wind tunnel
9
Noise index of test section: at the designed wind speed, the
aerodynamic noise sound pressure level is less than 85 dBA
at the wind tunnel diameter, one and a half times the
distance from the wind tunnel center
10
Temperature control index: design wind speed V 0 = 100 m/s,
T max < 5 0 (running continuously for half an hour)
11
Power system: variable frequency ac motor, stepless speed
control system
12
The measurement control system is controlled by computer
(data acquisition, wind speed acquisition and control)
P. Liu
measures can be conducted in it. D5 wind tunnel has a good flow field
quality and low background noise level, and its aerodynamic noise index
meets the design requirements (as shown in Table 6.1). The D5 aeroacoustic wind tunnel is composed of a test section, diffusion section, corner
section, power section, and stability section. The overall length, width, and
height of the wind tunnel are 25.58 m, 9.2 m, and 3.0 m. The section of
the test section is square, with a width of 1.0 m and a height of 1.0 m.
The length of the closed test section is 2.5 m, the length of the open test
section is 2.0 m, and the length of the air collector is 0.5 m. The test
section is open and closed. There is a full anechoic chamber of 7 m ×
6 m × 6 m surrounding the test section. When the wind tunnel runs in
an open-jet form, it is a typical aeroacoustic wind tunnel. Both conventional aerodynamic and acoustic tests can be conducted in the D5 wind
tunnel.
The center line of the wind tunnel test section is 2.0 m above the
ground. The wind tunnel structure is made of pure steel, and the thickness of the tunnel wall is 6 mm. In order to improve the main frequency
Table 6.1 Main aerodynamic and acoustic design indexes of D5 wind tunnel
The serial number
Project
1
Test section dimensions: length 2.5 m, width 1 m, height 1 m,
contraction ratio 9
2
Velocity of open test section: V 0 = 1.5−80 m/s
Velocity of closed test section: V 0 = 1.5−100 m/s
3
Turbulence in the test section: ε =
u 2
V 0 = 1 − 0.08%
4
Velocity instability of test section: <1%
5
Mean speed deviation of test section:V < 1%
6
Deviation Angle of air flow at space point:
α ≤ ±0.5 0 ;β ≤ ±0.5 0
Mean flow deflection angle: α ≤ ±0.1 0 ;β ≤ ±0.1 0
7
Axial static pressure gradient in the test section:
dp
dx
< 10 Pa/m
8
Microperforated plate silencer is used in the fan section of
the wind tunnel
9
Noise index of test section: at the designed wind speed, the
aerodynamic noise sound pressure level is less than 85 dBA
at the wind tunnel diameter, one and a half times the
distance from the wind tunnel center
10
Temperature control index: design wind speed V 0 = 100 m/s,
T max < 5 0 (running continuously for half an hour)
11
Power system: variable frequency ac motor, stepless speed
control system
12
The measurement control system is controlled by computer
(data acquisition, wind speed acquisition and control)