This standard specifies the method for measuring the sound power radiated into a duct by a fan. This method is used to measure the sound power radiated into a duct with a silencer end at the inlet and/or outlet of the fan. This standard applies to fans that radiate steady-state wide, narrow-band and discrete-frequency noise. GB/T 17697-1999 Acoustics Determination of sound power radiated into a duct by a fan Duct method GB/T17697-1999 Standard download decompression password: www.bzxz.net
This standard specifies the method for measuring the sound power radiated into a duct by a fan. This method is used to measure the sound power radiated into a duct with a silencer end at the inlet and/or outlet of the fan. This standard applies to fans that radiate steady-state wide, narrow-band and discrete-frequency noise.

GB/T 17697—1999 This standard is based on the international standard ISO5136:1990. It is equivalent to the international standard in terms of technical content. It is formulated based on the determination of sound power radiated by fans by duct method. Appendices A and B of this standard are standard appendices, and appendices C, D, E, F and G are informative appendices. This standard is proposed and managed by the National Technical Committee for the Promotion of Acoustic Standards. The drafting units of this standard are Wuhan Blower Co., Ltd. and Beijing Institute of Labor Protection Science. The main drafters of this standard are Zhou Guohua and Ren Wentang. GB/T17697
ISO Foreword
The International Organization for Standardization is a worldwide organization composed of national standardization committees (ISO member states). The formulation of national standards is usually completed by 15 technical committees. Each member state has the right to participate in the technical committee when it is interested in a standard determined by the technical committee. Governments and non-governmental international organizations that have ties with ISO can also participate in the work. The International Organization for Standardization (ISO) and the International Engineering Committee (IEC) maintain close cooperation in all aspects of electrotechnical standardization. The draft international standards adopted by each technical committee should be distributed to each member state for voting. The draft international standard needs at least 75% of the member states to vote in favor before it can be published as an international standard. The international standard ISO5136 is proposed by ISD/TC43 Acoustics Technical Committee. Appendix A and Appendix B are the appendices of the standard, and Appendix C to Appendix G are indicative and for reference only. National Standard of the People's Republic of China
Determination of sound power radiated into a duet hyfans-[n-duct metbod
1 Scope
1.1 Measurement conditions
GB/T 17697--1999
eqv ISO 5136:1990
This standard specifies the basic method for measuring the sound power radiated into a duet hyfans-[n-duct metbod. This method is used to measure the sound power radiated into a duct with a silencer end at the inlet and/or outlet of the fan. This standard is applicable to fans that radiate wide, narrow-band and discrete frequency noise, and the measurement air temperature range is 0 to +70.
The diameter of the test pipe ranges from 0.15 to -2 m. The maximum allowable flow velocity is 30 m/s. The maximum airflow swirl angle is 15. The center frequency range of the measured 1/3 frequency band is 50 to 10 000 Hz. Note: At high flow velocities and large airflow swirl angles, the airflow noise of the sampling pipe will have an adverse effect on the measurement. The determination of the airflow swirl angle requires reference to 1.2 Types of sound sources
The comparison method is suitable for determining the sound power radiated into the pipe by a fan connected to a temporary duct. The duct fans or fan equipment involved in this standard include: duct centrifugal fans;
duct axial flow fans;
-duct mixed flow fans.
This standard also applies to other pneumatic sources, such as air intake boxes, air flow adjustment and throttling devices: This standard does not apply to non-ducted fans or any other ducted fan equipment. 1.3 Measurement method uncertainty
The uncertainty of this measurement method is expressed as the standard deviation of the sound power level measurement. It includes the end reflection, the key pipe, the error that may be caused by calculating the sound power based on the sound pressure measurement, and the standard of the measuring instrument. The values ​​specified for the predicted standard deviations are given in Table 1. Standard deviations for measurements
1/3 times the frequency, 14z
80-100
125-~4000
Approved by the State Administration of Quality and Technical Supervision on March 8, 1999.d
Implementation on September 1, 1999
GB/T 17697 1999
The standard deviations shown in Table 1 reflect the cumulative effect of all factors affecting the measurement accuracy. They do not include changes in sound power due to the fan or the test, such as changes in installation or source conditions. 1 The accuracy of the measurement is reduced in the presence of air currents. If remote frequency components are present, or if the measurement is not averaged over a sufficiently long period of time, the accuracy will be lower than the deviations shown in Table 1. \At high frequencies, especially above 4000 Hz, when the measured noise level decreases rapidly with frequency, the data listed in Table 1 may increase: under such conditions, the high-frequency sound pressure level detected by the microphone may be smaller than the low-frequency sound pressure level, and the electric sound, especially the electric sound from the frequency analyzer, may interfere with the high-frequency sound signal. In order to ensure the accuracy of the sound power measurement, a high-frequency filter can be used before the frequency analyzer to reduce the high-frequency sound measurement band. 4 The standard deviation report data of the measurement methods listed in Table 1 can be found in Appendix G References [3]. [3], [9]. 2 Referenced Standards
The provisions contained in the following standards constitute the text of this standard through reference in this standard. At the time of publication of this standard, the versions shown are valid. All standards are subject to revision and parties using this standard should investigate the possibility of using the latest version of the following standards. GB/T 3240—1982 Frequencies commonly used in acoustic measurements (NCG IS0266:1975) GB/T3241—1998 Octave and fractional octave filters (EJEC1260:1995) GB/T3785—1983 Electrical and acoustic properties and test methods of sound level meters JSO5221:1984 Air flow distribution and hysteresis—Rules for measuring air flow in air transmission ducts ISO7235:1991 Acoustics—Acoustic measurement methods for duct silencers—Insertion loss, air flow noise and total force loss 3 Definitions and symbols
This standard adopts the following definitions and symbols.
3.1 Fan inlet (outlet) area (Sr) fan inlet (outlet) area is the area of ​​the fan inlet (outlet) connected to the test duct. 3.2 Ducts Any of the ducts described in 3.2, 1, 3.2.2, 3.2.3. 3.2.1 Test duet The duct in which the power of the fan is measured. 3.2.2 Terminating duct The duct having a silencer terminal connected to the test duct. 3.2.3 Intermediate duct The duct installed at the inlet and/or exhaust of the fan to ensure the required airflow conditions. If necessary, it includes the transition of the section change.
3.3 Measurement plane The lateral plane in the test channel where the diaphragm of the measuring microphone is located. 3.4 Sound pressure level (I,) The logarithm to the base 10 of the ratio of the sound pressure to the reference sound pressure multiplied by 2, in units of Baermen, 13. However, it is usually expressed ind
ta H. td2 - d).He (d/d,y -- 10.934h
45,h,
223.81 +-21 will 2 table
Intermediate pipeline
Test pipeline
Synchronous measurement of inlet and outlet pipeline noise
Terminal pipeline
Unit: rm
Silencer and throttling device
(Schematic diagram of medical
secretion volume
(Schematic diagram]
Among them:
Flow rate vice Quantity and appearance system
(illustration country)
fan with air intake pipe
[illustration attachment]
among which: 24
elimination origin code| |tt||(Dongxi map)
GB/T 17697--1999
Wei or cabinet shape to
National shape through teaching management
Zhongshang pipeline
Test camp road
Without export|| tt||The fan of the consultation channel
meter coiled pipe avoidance
Figure? Only measure the noise of the inlet channel (except all the sizes are the same as the figure) male weak rectangle to
circle The shape is too light
The sound is too light
(Schematic diagram)
The fan without air inlet duct
Transition answer
Middle question general road||tt ||Noise reduction
Test risk
Unit: m
With outlet pipe
Can be measured fan||tt| |Unit: m
and control
(energy diagram)
washing volume, ketone volume and difference system
(show sharing)
end pipeline|| tt||Figure 3 only measures the noise of the exit channel (except that all dimensions are the same as Figure 1) 4.2.6 Adjustment device
GB/T17697-1999
When necessary, install the silencer at the end of the fan away from the fan An adjustable flow device is installed at the tail end. No other throttling device is installed between the fan and the silencer end. The throttling section should have an adjustable function to adjust the working conditions when measuring the fan sound power: throttling device and silencer end The device structure should be designed so that the sound pressure level generated by the throttling device in the test pipe is at least lower than the sound pressure level of the test pipe. dB.bZxz.net
Recommended section with back mount (
4.3 Measuring instruments
4.3.1 Ratio measurement system
4.3.1.1 Microphone
should be a microphone that meets the requirements of the Type 1 municipal meter specified in (B/T3785). The size of the microphone should be suitable for the sampling tube. 4.3.1.2 Microphone cable
Microphone and cable system Its sensitivity shall not vary with the temperature during the test, and no noise that interferes with the measurement panel shall be generated, whether due to the movement of the microphone or the bending of the microphone core caused by the airflow blowing across the cable. Other microphone amplifiers Sound level meters or other amplifiers used to amplify microphone signals should comply with the technical requirements of Type 1 sound level meters specified in GB 3785 and use a linear frequency response (Lin).
4.3.2 Frequency Analyzer
Use 1/3 octave band filter that meets the requirements of G13/3241. The center frequency of the filter can be found in GB/3240. 4.3.3 Sampling Tube||tt| |To maintain a sufficient signal-to-noise ratio, the sampling tube should reduce the end flow pressure fluctuation at the measurement position (see 6.2.1). The sampling tube and its use should meet the following requirements:
a) Compared with the nose can , reduce the end flow noise by at least 10 dB within the measurement rate range. The actual attenuation of the end flow noise associated with different frequencies and flow rates should be known to determine the signal-to-noise ratio specified in 6.2.1 (see Appendix B and Table E1 ), b) the maximum diameter of the sampling tube is 22mm
c) the normal incidence of each effective "/3 pecking order" of the incoming sampling tube should be determined The frequency response correction value C should be within 0.5 dB for the plane wave field emitted from the front. If the test is carried out in a free field, the short distance between the field microphone and the sampling tube should be kept at 3m. At the sampling room, the frequency response correction curve should be flat and clear. If a purchased sampling tube is used, the correction curve provided by the manufacturer and drawn according to the frequency response correction requirements should be used. If it meets the requirements, it can be used directly. d) In the free field When measuring the noise with a 1/3 octave bandwidth, the indicative characteristics of the sampling tube shall be within the limits specified in Figure 4.
1000E[z
4Hz|| tt||GB/T 176971999
200011 yuan
Sampling tube directivity limit characteristic curve
Note 1, the curve in Figure 4 is obtained from the following formula, A1 = 20lg -7.KC||tt ||U s 0 . 1, 31 Iad
Wu Zhong: ar.
is the sensitivity when the incident angle is compared with the sensitivity when the incident angle is (-0\) on the axis The attenuation is the most. Directivity constant, its limit value is shown in the following table; K
1/3 times the center of the band is narrow, H;
angle of incidence, tad
directivity Constant polar value
1/3 frequency multiplication center frequency
0.35×103
0.35×10-3
0.95 ×10-8
To 2: The sampling arm directional characteristics provided by the manufacturer can only be used within the range specified in Figure 2. ) Flow rate compensation value C, see Table 4.
Model The positive values ​​of state are shown in Table 5.
1. 5 × 10-#
1. 5 × 10-
3. 2 × 10-3
g） Examples of sampling tubes are given in Appendix E. Typical attenuation of end flow pressure fluctuations as a function of 1/3 octave band flow rate compared to single-stage tubes is given in the table.
Note: It is recommended to use tubes made by specialized manufacturers whenever possible. Sampling tube, 1/3 borrowing band
center rate,
GH/T 17697-1999
Table 4 Sampling tube frequency response flow velocity correction value C Mach number range (flow velocity / speed of sound)
0. 011 70. C17 50. 023 3, 0. 429 2C- 035 00. 04C 8 0. 045 6 0. 052 50. 058 30. 064 1/c. 070 00. 075 R 0. 081 6<0. 311 ≤0. 023 3 3 325 2<0. 035 0].
<5. 04F 6/<5. 052 5
0. 054 -. 07c n[0. 275 80. 0916≤0. 055 3
20°C The velocity range of the measured radiation in air, unit: m/g (e=343 m/s)4
： 14-
Note: For each ratio, the upper value is the positive value of the flow velocity at the node outlet (the sound and the airflow are in the same direction) and the lower value is the corrected value of the flow velocity at the pipe inlet (the sound and the airflow are in the opposite direction). )
Sampling frequency response modal correction value center
1/3 times lazy band
Center lazy rate
Diameter range of test pipe n
Radial relative position 2 r/d=0.8
Radial relative position 2 r/d--0.65
0.15d<0.2/c.2u<0.3 1 0.3d0.5, 0.5≤d<0.80-Hd1.25
wW1.26d-2
1/3 frequency error
center||tt ||5 (0DE)
GB/T 17697 - 1999
Table 5 (Complete)
Diameter range of test pipe d,1n
Diameter machine position 2 /= 0.8
0.154≤0.2
0.2-d0.3
4,3,4 Sound level recorder or data sampling device0.3d0,5
Radial alignment position r1d-0.6
0.354-0.8
0.8x5,d-1.25
Sound level record At least or other data sampling devices meet the requirements of Type I test instruments specified in GB/T3785. 4.3.5 Multi-channel system
1. 25sdc23
If the method of 5.2.2b is adopted, the multi-channel system shall be qualified and the actual energy equivalent average value of each sound card level of each channel shall be within 20.5 within the whole frequency range. Within d distance, 4.4 System calibration
A registered Class 1 calibrator shall be used to calibrate the microphone without sampling tube: it shall be used to calibrate the entire measurement system before and after each series of tests. The calibrator shall be regularly calibrated every year: the porous part of the rotating tube shall be clean and undamaged. 5 Test arrangement
5.1 Installation of sampling tube
The microphone with sampling tube shall be installed on the measuring plane in the test pipe as shown in Figure 1. The microphone with sampling tube shall be installed along the axial direction of the pipe and towards the fan. For fan inlet measurements, the tube disc shall be facing the fan. The tube end of the microphone shall be rounded, which can reduce the airflow noise. Note: See Appendix E for typical installation flow diagrams.
5.2 Sampling tube position
5.2.1 Radial position
The sampling arm shall be installed in the radial position shown in Table 6 (see Figure 5). Agricultural sample opening plate
Kushun Kao Neng Vortex Direction
Pingxiang Tube
Test Camp
Radial Position of Sampling Tube
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