1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2013 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/ARP5759 AEROSPACE RECOMMENDED PRACTICE ARP5759 Issued 2013-01 Acoustical Consider
5、ations for Engine Test Cells RATIONALE One of the primary purposes of engine test cells is reduce the sound emissions from the operating engine to the outside facility or community. The successful reduction and control of this noise requires specialized knowledge, experience, and execution. This pap
6、er explores the definitions, requirements, basic science, and recommendations for a test cell operator to select and evaluate qualified solutions and contractors for test cell noise reduction. TABLE OF CONTENTS 1. SCOPE 4 1.1 Purpose . 4 1.2 Beneficiaries 4 1.3 Considerations and Consequences of Imp
7、roper Acoustic Design/Installation . 4 2. APPLICABLE DOCUMENTS 4 2.1 SAE Publications . 4 2.2 Other Applicable Publications . 5 2.3 Definitions . 5 3. ALLOWABLE NOISE LIMITS . 6 3.1 Test Cell Noise Regulations 6 3.1.1 Test Cell Location . 6 3.1.2 Local Airport or Industrial Park Regulations . 6 3.1.
8、3 Local Community Ordinances . 6 3.1.4 AICUZ Air Installations Compatibility Use Zones. 7 3.1.5 OSHA Occupational Safety and Health Administration . 7 3.1.6 HSE Health and Safety Executive . 7 3.1.7 Company Standards and Regulations 7 3.2 Usual Industry Practice for Noise Reduction Standards . 7 3.3
9、 Infrasound . 7 3.4 Perceived Noise Sensitivity and Susceptibility . 8 4. BASICS OF TEST CELL NOISE AND NOISE REDUCTION . 8 4.1 What is Sound? . 8 4.2 What is Noise? 8 4.3 Turbofan Engine Noise . 8 4.4 Sound Intensity . 9 4.5 Sound Propagation . 9 SAE ARP5759 Page 2 of 24 5. BASICS OF TEST CELL NOIS
10、E AND NOISE REDUCTION . 9 5.1 Test Cell Noise Reduction System Components 9 5.2 Barriers 9 5.3 Absorption . 10 5.4 Directivity . 11 5.5 Special Devices . 11 5.5.1 Augmentor Tube Divergent Diffuser . 11 5.5.2 Blast Basket 11 5.5.3 Centerbody 11 5.5.4 Conical Target . 11 5.5.5 Diffuser Screen . 11 5.5
11、.6 Exhaust Collector 11 5.5.7 Helmholz Resonators 11 5.5.8 Ring Diffuser . 11 5.5.9 Secondary Telescopic Inlets and Changing the Space between Engine and Augmentor Tube 12 5.5.10 “Soft” Augmentor Tube . 12 5.6 Active Noise Control . 12 6. SPECIAL CONSIDERATIONS FOR TEST CELL NOISE REDUCTION . 12 6.1
12、 Test Cell Airflow 12 6.1.1 Air Velocity 12 6.1.2 Inlet Air Flow Quality . 13 6.2 Exhaust Temperature . 13 6.3 Exposure to the Elements . 13 6.3.1 Water-soaked Acoustic Elements . 13 6.3.2 Corrosion . 13 6.3.3 Cold Soak 13 6.4 Foreign Object Damage 14 6.5 Site Location . 14 6.6 Equipment Noise Measu
13、rement 14 6.7 Secondary Noise Leaks 14 6.8 Special Considerations for Afterburning Engines . 15 7. MATERIALS, FABRICATION, AND INSTALLATION . 15 7.1 Typical Construction of Baffle . 16 7.2 Materials 17 7.2.1 Common Structural Materials . 17 7.2.2 Internal Frame . 17 7.2.3 Perforated Skin . 18 7.2.4
14、Acoustic Fill Material . 18 7.2.5 Acoustic Fill Facing Material . 19 7.3 Fabrication 19 7.3.1 Complete Assembly 19 7.3.2 Welded or Riveted. 20 7.3.3 Acoustic Material Fill . 20 7.4 Installation . 20 7.4.1 Transportation . 21 7.4.2 Site Storage 21 7.4.3 Cranes and Access . 21 7.4.4 Installation Logis
15、tics 21 7.4.5 Attachment 21 7.4.6 Cleaning and Debris Removal 22 8. SPECIFICATIONS, CONTRACTING, DOCUMENTATION . 22 8.1 Performance Specification 22 8.1.1 Engines to be Tested or Source Noise . 22 8.1.2 Level of Exterior Audible Acoustic Performance . 22 8.1.3 Adjustment of Requirements due to Exist
16、ing and Future Buildings . 23 8.1.4 Specify Performance to meet applicable codes 23 SAE ARP5759 Page 3 of 24 8.1.5 Level of Acoustic Performance in the control room 23 8.1.6 Level of Acoustic Performance in the preparation room . 23 8.1.7 Level of Acoustic Performance in adjacent buildings . 23 8.1.
17、8 Level of Infrasound Performance 23 8.1.9 Length of Service Life . 23 8.2 Validation 24 9. NOTES 24 FIGURE 1 SCHEMATIC ILLUSTRATION OF A MODERN ENGINE TEST CELL 10 FIGURE 2 CROSS SECTION ILLUSTRATION OF TYPICAL ACOUSTIC BAFFLE . 16 SAE ARP5759 Page 4 of 24 1. SCOPE 1.1 Purpose This document discuss
18、es, in broad and general terms, the subject of acoustical considerations in engine test cells. One of the primary purposes of an engine test cell is to control the noise emanating from the operating engine in order to reduce noise in the surrounding facility and community to acceptable levels. This
19、is done by the design and installation of specialized acoustic elements and features, which need to be fully integrated into the overall test cell design. It should be further noted, that the requirements of acoustic control are critical to the proper operation of the engine, safety of plant equipme
20、nt and personnel, and meeting local and legal noise requirements. 1.2 Beneficiaries This document is a compilation of input from several test cell designers, operators and users that summarizes the best practices and recommendations from these experts. This document is intended to benefit operators
21、and owners of engine test cells who are contemplating new facilities, refurbishment of existing facilities, and addition of new engine models to existing facilities. It is intended to aid these owners in understanding the basic terms, regulations, and concerns with engine test cell acoustics. It is
22、not intended that this document be an exhaustive design guide that any owner or contractor could independently accomplish the task of test cell acoustic design and installation. Rather, it is intended to provide a basic knowledge and understanding to operators and owners in the selection and evaluat
23、ion of acoustic designs and contractors. 1.3 Considerations and Consequences of Improper Acoustic Design/Installation When choosing a contractor for the design and installation of an acoustic solution for an engine test cell, potential risks and loss of productivity should be carefully considered. T
24、he consequences of an improperly selected, designed, or installed acoustic system can greatly vary in scope and impact to the customer. Schedule loss can impact and delay the facility ready for operation scheduling. Operational loss can directly create financial and reputation loss due to lost opera
25、tion and test time for the backlog of engines ready for test. Physical loss can cause loss of life of personnel, engine equipment and surrounding facilities. Financial loss ties in with all of the above where those causes create a financial loss effect. 2. APPLICABLE DOCUMENTS The following publicat
26、ions form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cit
27、ed herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7
28、323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AIR4827 Modeling Techniques for Jet Engine Test Cell Aerodynamics AIR4869 Design Considerations for Enclosed Turbofan/Turbojet Engine Test Cells AIR4989 Design Considerations for Enclosed Turboshaft Engine Test Cells AIR5303 Inf
29、rasound Phenomenon in Engine Test Cells SAE ARP5759 Page 5 of 24 2.2 Other Applicable Publications ISO 7196 Acoustics Frequency-Weighting Characteristic for Infrasound Measurement BS4142 Method for Rating Industrial Noise Affecting Mixed Residential and Industrial Areas 2.3 Definitions ACOUSTIC ELEM
30、ENT: Any major assembly, component, or sub component of the equipment in the test cell that is used for acoustic control of noise in a test cell. AUDIBLE SPECTRUM: Acoustic energy in the frequency range normally heard by the human ear. In test cell acoustics this is normally from 20 to 20 000 Hz. BA
31、FFLE: An acoustic element, normally installed directly in the test cell air stream intended to attenuate acoustic noise. Baffles are most usually metal structures filled with acoustic absorbing material. DECIBEL: A unit of measure of the loudness or intensity of noise. dB: Abbreviation for decibels.
32、 dBA: Abbreviation for decibels adjusted. A measure of the absolute noise power weighted to the sensitivity of the human ear dBG: Unit of measure for infrasound. FOD: Abbreviation for Foreign Object Damage. Loose materials, unsecured hardware, and debris which could be ingested by an engine. HERTZ:
33、Unit of measure of frequency equal to 1 cps. Hz: Abbreviation for Hertz. INFRASOUND: Acoustic energy with a frequency below what the human ear can normally hear. Usually defined as between 0 and 32 Hz. OSHA: Abbreviation for U.S. Occupational Safety and Health Administration. SOUND POWER LEVEL (Abbr
34、eviation PWL): The sound power level of a source is expressed in decibels (dB) and is equal to 10 times the logarithm to the base 10 of the ratio of the sound power of the source to a reference sound power. The reference sound power level in air is normally taken to be 10-12W. wattspowerreferenceWhe
35、repowerreferencepowersoundLogLevelPowerSound121010)()(10=(Eq. 1) SAE ARP5759 Page 6 of 24 SOUND PRESSURE LEVEL (SPL): The sound pressure level of a source is expressed in decibels (dB) and is equal to 20 times the logarithm to the base 10 of the ratio of the sound pressure of the source to a referen
36、ce sound pressure. The reference sound power level in air is normally taken to be 2 x 10-5N/m2. 252210102)()(10PrmNpressurereferenceWherepressurereferencepressuresoundLogLevelessureSound=(Eq. 2) 3. ALLOWABLE NOISE LIMITS One of the most commonly misunderstood concepts about test cell acoustics is: “
37、What is the normal (or standard) allowable noise limit from a test cell?” In reality, there is no uniform, regulated, national or international, standard for allowable noise from a test cell. In practice, the test cell owner and acoustic contractor, must establish the agreed-upon noise level from th
38、e test cell, in full consideration of myriad sources. It should be noted that in some cases, and in some locations, little or no regulations may exist. Due diligence is required to research and establish the noise limit criteria based on all applicable ordinances or regulations. 3.1 Test Cell Noise
39、Regulations 3.1.1 Test Cell Location The first consideration is the location and site of the test cell. Is the test cell on extremely remote land where noise regulations do not exist? If a remote location, will future land development in the surrounding area be a factor? Is the test cell to be locat
40、ed on airport property? In an industrial park? Near a residential community? Near a wildlife refuge? Near agricultural animals? Near other office buildings or facilities? Near a property line? Near sensitive or precision manufacturing facilities? etc. Answers to these questions will be the first ste
41、p to identify any and all applicable ordinances or regulations. 3.1.2 Local Airport or Industrial Park Regulations In the case of test cells built on airport property (the most common location), the first source for establishing the allowable test cell noise and any physical height restrictions are
42、the local airport regulations. If such regulations exist, they may establish the allowable noise, from any source, that may impinge on other facilities or locations on the airport property. They may also establish the allowable noise, from any source, at the property line. Regulations on maximum bui
43、lding height elevations will also often drive an acoustic design as well as drive the location of the test cell stacks on the property. Consideration and provision should be allowed in the design to be able to comply with possible future changes in local ordinances. Provision for adding more acousti
44、c treatment to an existing building design can account for this future proofing for new ordinances. Periodic acoustic surveys and testing may be required by local ordinances. 3.1.3 Local Community Ordinances Many residential communities may have established local ordinances that limit the noise from
45、 sources within, or adjacent to, the community. In some cases, there may be different noise limits for daytime or nighttime, from fixed or mobile sources, or for limits on the duration of the noise. An area of concern with some local ordinances may be in the fact that the noise requirements are lowe
46、r than the background noise, such as highway or aviation traffic in the vicinity of the facility. This poses a difficulty in evaluating the noise performance of the test cell to assure compliance, as the background noise must be eliminated or filtered out to collect meaningful noise-data from the te
47、st cell. SAE ARP5759 Page 7 of 24 3.1.4 AICUZ Air Installations Compatibility Use Zones To balance the needs of aircraft operations and community concerns, the goal of the Department of Defenses (DoDs) Air Installations Compatible Use Zones (AICUZ) is to protect the health, safety and welfare of tho
48、se living near military airfields while preserving the defense flying mission. The AICUZ guidelines define zones of high noise and accident potential and recommend uses that are compatible within these zones. Local planning agencies are encouraged to adopt these guidelines. 3.1.5 OSHA Occupational S
49、afety and Health Administration The U.S. Occupational Safety and Health Administration established a number of guidelines regarding noise, primarily to protect the health of personnel. The OSHA guidelines are used primarily in and around the test cell rather than noise radiated to the community. Often the OSHA requirements can be met by design of the test cell, the use of hearing protection devices, or both.
