1、 ANSI/ASA S12.76-2017 AMERICAN NATIONAL STANDARD Methods for Measurement of Supersonic Jet Noise from Uninstalled Military Aircraft Engines Accredited Standards Committee S12, Noise Standards Secretariat Acoustical Society of America 1305 Walt Whitman Road, Suite 300 Melville, NY 11747 ANSI/ASAS12.7
2、6-2017 The American National Standards Institute, Inc. (ANSI) is the national coordinator of voluntary standards development and the clearinghouse in the U.S.A. for information on national and international standards. The Acoustical Society of America (ASA) is an organization of scientists and engin
3、eers formed in 1929 to increase and diffuse the knowledge of acoustics and to promote its practical applications. ANSI/ASA S12.76-2017 AMERICAN NATIONAL STANDARD Methods for Measurement of Supersonic Jet Noise from Uninstalled Military Aircraft Engines Secretariat: Acoustical Society of America Appr
4、oved on March 27, 2017, by: American National Standards Institute, Inc. Abstract This standard describes procedures to measure jet noise from uninstalled military aircraft engines with supersonic exhaust flows. The methods pertain to propulsion systems mounted on outdoor test stands with appropriate
5、 inlets and representative nozzles. Detailed measurement procedures are described for near-field acoustical characterization. These data can be used to establish baseline noise levels, assess effectiveness of noise reduction technologies, estimate personnel noise exposure, and provide full-scale dat
6、a for refinement of engine noise models. Far-field measurement procedures are described to provide data for estimates of community noise. This standard describes required measurement instrumentation, signal processing, data formatting, and measurement uncertainty. This standard does not apply to com
7、mercial engines, dual-use engines, or other engines covered by FAA/ICAO noise certification requirements. AMERICAN NATIONAL STANDARDS ON ACOUSTICS The Acoustical Society of America (ASA) provides the Secretariat for Accredited Standards Committees S1 on Acoustics, S2 on Mechanical Vibration and Shoc
8、k, S3 on Bioacoustics, S3/SC 1 on Animal Bioacoustics, and S12 on Noise. These committees have wide representation from the technical community (manufacturers, consumers, trade associations, organizations with a general interest, and government representatives). The standards are published by the Ac
9、oustical Society of America as American National Standards after approval by their respective Standards Committees and the American National Standards Institute (ANSI). These standards are developed and published as a public service to provide standards useful to the public, industry, and consumers,
10、 and to Federal, State, and local governments. Each of the Accredited Standards Committees (operating in accordance with procedures approved by ANSI) is responsible for developing, voting upon, and maintaining or revising its own Standards. The ASA Standards Secretariat administers Committee organiz
11、ation and activity and provides liaison between the Accredited Standards Committees and ANSI. After the Standards have been produced and adopted by the Accredited Standards Committees, and approved as American National Standards by ANSI, the ASA Standards Secretariat arranges for their publication a
12、nd distribution. An American National Standard implies a consensus of those substantially concerned with its scope and provisions. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interest
13、s. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered and that a concerted effort be made towards their resolution. The use of an American National Standard is completely voluntary. Their existen
14、ce does not in any respect preclude anyone, whether he or she has approved the Standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the Standards. NOTICE: This American National Standard may be revised or withdrawn at any time. Th
15、e procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this Standard. Acoustical Society of America Standards Secretariat 1305 Walt Whitman Road, Suite 300 Melville, New York 11747 Telephone: 1 (631) 390-0215 Fax: 1 (631)
16、923-2875 E-mail: asastdsacousticalsociety.org 2017 by Acoustical Society of America. This standard may not be reproduced in whole or in part in any form for sale, promotion, or any commercial purpose, or any purpose not falling within the provisions of the U.S. Copyright Act of 1976, without prior w
17、ritten permission of the publisher. For permission, address a request to the Standards Secretariat of the Acoustical Society of America. 2017 Acoustical Society of AmericaAll rights reserved iContents 1 Scope . 1 2 Normative references . 1 3 Terms and definitions . 2 4 Noise data acquisition system
18、requirements . 4 4.1 Microphones and preamplifiers 4 4.2 Digital recording system . 5 5 Measurement site 6 5.1 Terrain 6 5.2 Ground impedance optional far-field measurements only . 6 5.3 Weather requirements 7 6 Measurement methods 7 6.1 General procedures 7 6.2 Engine performance measurement method
19、s . 8 6.3 Near-field method . 8 6.4 Optional far-field method using elevated microphones 10 7 Data analysis . 12 7.1 Weather analysis 12 7.2 Spectral analysis . 12 7.3 Uncorrected pressure-time histories pressure vs. time . 13 7.4 Corrected one-third octave-band spectra . 13 7.5 Overall levels 13 7.
20、6 Engine performance histories . 13 8 Reporting and test documentation . 13 8.1 Calibration records 13 8.2 Weather data 13 8.3 Test log / scribe notes 14 8.4 Instrumentation setup log . 14 8.5 Test location data . 14 8.6 Ground impedance data optional far-field measurements only . 14 8.7 Engine perf
21、ormance data . 14 8.8 Raw noise measurement data 14 8.9 Reduced noise data 14 8.10 Uncertainty 16 Annex A (normative) Measurement uncertainty for near-field noise measurements 17 A.1 Measurement uncertainty . 17 Annex B (informative) Microphone cable length considerations . 20 Annex C (normative) Ob
22、structions and reflections 22 C.1 Obstructions 22 C.2 Field reflections check 22 Bibliography 23 2017 Acoustical Society of AmericaAll rights reserved iiFigures Figure 1 Uninstalled engine ne ar-field microphone locations 9 Figure 2 Uninstalled engine far-field microphone locations . 11 Figure 3 Exa
23、mple of an ASCII header mirroring the contents of the database description document 15 Figure B.1 Maximum frequency as a function of cable length for constant current supply levels of 2, 4, 10, and 20 mA for coaxial cable type and maximum output sensor voltages of: a) RG-58 and 1 V, b) RG-58 and 10
24、V, c) RG-59 and 1 V, d) RG-59 and 10 V 21 Tables Table A.1 Uncertainty budget for method A elevated engine nea r-field noise measurement methods . 18 Table A.2 Uncertainty budget for the optional method C far-field noise measurement methods 19 2017 Acoustical Society of AmericaAll rights reserved ii
25、iForeword This Foreword is for information only and is not a part of the American National Standard ANSI/ASA S12.76-2017 American National Standard Methods for Measurement of Supersonic Jet Noise from Uninstalled Military Aircraft Engines. As such, this Foreword may contain material that has not bee
26、n subjected to public review or a consensus process. In addition, it does not contain requirements necessary for conformance to the standard. This standard comprises a part of a group of definitions, standards, and specifications for use in noise. It was developed and approved by Accredited Standard
27、s Committee S12, Noise, under its approved operating procedures. Those procedures have been accredited by the American National Standards Institute (ANSI). The Scope of Accredited Standards Committee S12 is as follows: Standards, specifications, and terminology in the field of acoustical noise perta
28、ining to methods of measurement, evaluation, and control, including biological safety, tolerance, and comfort, and physical acoustics as related to environmental and occupational noise. This standard is not comparable to any existing ISO Standard. At the time this Standard was submitted to Accredite
29、d Standards Committee S12, Noise, for approval, the membership was as follows: S.J. Lind, Chair D.F. Winker, Vice-Chair N.B. Stremmel, Secretary 3M Occupational Health FAX: 631-923-2875; E-mail: asastdsacousticalsociety.org. 2017 Acoustical Society of AmericaAll rights reserved vi Introduction Noise
30、 from military aircraft can impact the hearing and performance of nearby personnel and can be a source of annoyance to people living near airbases, airports, and ranges where such aircraft operate. Federal agencies operating airfields are required to analyze the noise impacts by proposed new flight
31、operations as part of the environmental analysis that is required by the National Environmental Policy Act of 1969 (NEPA). Additionally, overexposure of flight line/flight deck personnel to high levels/durations of noise can adversely affect hearing and negatively impact voice communication capabili
32、ty. It is advantageous to assess the noise emissions from new and existing engine/propulsion systems prior to the design, installation, and flight test in a new aircraft. During the development of new engines/propulsion systems and technologies, including noise reduction techniques and technologies,
33、 it is desirable to measure and compare the new uninstalled engine noise emissions with legacy engines or prior versions of the new engine. This standard provides the methods to conduct such measurements. Accurate, reliable, and repeatable noise measurements from standardized techniques enable confi
34、dence in the data used to establish baseline noise levels, assess effectiveness of noise reduction technologies, and provide full-scale data for refinement of engine noise models. It is understood that estimating the installed engine noise emissions for near-field personnel noise or community noise
35、using uninstalled engine data is a complex and difficult process. This standard was developed over a series of working group meetings and a public review meeting that formed consensus defining measurement methods that result in accurate, reliable, and repeatable noise data from the operation of unin
36、stalled military jet engines. The standard addresses important test considerations such as measurement site; instrumentation specifications; weather measurement and limits; and data formatting, organization, analysis, and reporting. The standard describes multiple methods for uninstalled engines at
37、two different heights with coarse or dense microphone arrays in the near-field and an optional method for a far-field array. AMERICAN NATIONAL STANDARD ANSI/ASA S12.76-2017 2017 Acoustical Society of AmericaAll rights reserved 1American National Standard Methods for Measurement of Supersonic Jet Noi
38、se from Uninstalled Military Aircraft Engines 1 Scope This standard describes procedures to measure jet noise from uninstalled military aircraft engines with supersonic exhaust flows. The methods pertain to propulsion systems mounted on outdoor test stands with appropriate inlets and representative
39、nozzles. Detailed measurement procedures are described for near-field acoustical characterization. These data can be used to establish baseline noise levels, assess effectiveness of noise reduction technologies, estimate personnel noise exposure, and provide full-scale data for refinement of engine
40、noise models. Far-field measurement procedures are described to provide data for estimates of community noise. This standard describes required measurement instrumentation, signal processing, data formatting, and measurement uncertainty. This standard does not apply to commercial engines, dual-use e
41、ngines, or other engines covered by FAA/ICAO noise certification requirements. 2 Normative references The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the ref
42、erenced document (including any amendments) applies. ANSI/ASA S1.1-2013 American National Standard Acoustical Terminology ANSI/ASA S1.6-2016 American National Standard Preferred Frequencies and Filter Band Center Frequencies for Acoustical Measurements ANSI/ASA S1.8-2016 American National Standard R
43、eference Values for Levels Used in Acoustics and Vibrations ANSI/ASA S1.11/IEC 61260 Parts 1, 2, 3 American National Standard Electroacoustics - Octave-band and Fractional-octave-band Filters Part 1: Specifications (nationally adopted international standards) ANSI/ASA S1.13-2005 (R2010) American Nat
44、ional Standard Measurement of Sound Pressure Levels in Air ANSI/ASA S1.15-1997/Part 1 (R2016) American National Standard Measurement Microphones Part 1: Specifications for Laboratory Standard Microphones ANSI/ASA S1.17-2014/Part 1 American National Standard Microphone Windscreens Part 1: Test Proced
45、ures for Measurements of Insertion Loss in Still Air ANSI/ASA S1.18-2010 American National Standard Method for Determining the Acoustic Impedance of Ground Surfaces ANSI/ASA S1.26-2014 American National Standard Method for Calculation of the Absorption of Sound by the Atmosphere ANSI/ASA S12.76-2017
46、 2017 Acoustical Society of AmericaAll rights reserved 2ANSI/ASA S1.40-2006 (R2011) American National Standard Specifications and Verification Procedures for Sound Calibrators ANSI/ASA S1.42-2001 (R2016) American National Standard Design Response of Weighting Networks for Acoustical Measurements ISO
47、/IEC Guide 98, Uncertainty of measurement 3 Terms and definitions For the purposes of this standard, the terms and definitions given in ANSI/ASA S1.1 and the following apply: 3.1 above ground level (AGL). The height (meters or feet) of a component, microphone, weather sensor, etc., above the average
48、 terrain level within a 1.5 m (5 ft) radius of the component center projected to the ground. 3.2 atmospheric absorption. Reduction of sound level due to various attenuation factors such as molecular relaxation and thermoviscous effects. 3.3 axisymmetric nozzle. A nozzle that is symmetric about the e
49、ngines longitudinal axis; i.e., a round or circular nozzle. 3.4 crest factor. The difference in dB between the peak sound pressure level and the rms sound pressure level. 3.5 crosstalk. A phenomenon where a signal on one line or channel is capacitively and/or inductively coupled to an adjacent line or channel. The level of the coupling is expressed as a ratio in dB of the coupling from one line or channel onto the adjacent line or channel. 3.6 directivity (of a microphone). Spectral and amplitude behavior, as a function of angle, from the dir
