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 theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2013 SAE International All rights reserved. No part of this publication ma
3、y 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: +1 724-776-4970 (outside US
4、A) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/ARP876FAEROSPACERECOMMENDEDPRACTICEARP876 REV. F Issued 1978-03 Revised 2013-05 Superseding ARP
5、876E Gas Turbine Jet Exhaust Noise Prediction RATIONALERevision F corrects an error in Equation 9 for the single stream shock-associated noise prediction method, and corrects an error in Table 14 for the mixed component Z4 term of the subsonic coaxial jet mixing noise prediction method. FOREWORDAIR8
6、76, issued on 7 October 1965, presented a summary correlation of jet engine exhaust noise data available at that time. It dealt with both static and flight modes but, by virtue of the data largely being from full scale engines, no attempt was made to subdivide the information into the relevant compo
7、nent noise sources. Subsequently, work on high-quality noise facilities has established that most engine exhaust systems are influenced in their noise characteristics by far more than the noise due to the external mixing process alone, and this work has provided the opportunity to develop a clearer
8、picture of the influence of other effects. AIR876 was also limited to jet velocities above 1000 feet/second (300 m/s), i.e., the range of exhaust velocities associated with early jet engines. The introduction of more advanced engine designs demands a prediction technique for exhaust sources over a f
9、ar wider range of velocity conditions. Therefore, it is intended that ARP876 be developed on a long-term basis as a document definitive in most aspects of the prediction of exhaust noise, consistent with the state of the art. Specific recommended procedures will be issued as sections, both for compl
10、eteness and to allow for future updating. Additionally, following a decision in 1979, explanatory background material detailing the rationale behind the selection of methods will be included in separate appendices to this document.The document will offer a method of estimating the exhaust noise from
11、 single unsuppressed engines. To be useful in estimating the noise from aircraft installations, a number of additional effects must be considered, and it is intended that these also will be covered as substantive evidence becomes available. Areas that will not be addressed in this ARP, due to source
12、 variability with detailed engine design parameters, are aerodynamic blade noise sources; that is, noise generated by interaction effects between rotating and stationary components of the fan, compressor and turbine systems. Each section will be dated, and will represent an approach to a particular
13、topic as agreed by members of the SAE A-21 Propulsion Noise Subcommittee who have experience or data on that subject. Lists of members and affiliated bodies contributing experimental data or other information used in compiling any one section will be included. Correspondence should be addressed to t
14、he SAE for the attention of the A-21 Committee and appropriate distribution. SAE ARP876F Page 2 of 103 TABLE OF CONTENTS 1. SCOPE 52. SOURCES OF EXHAUST NOISE 53. NOTES ON USE OF PREDICTION PROCEDURES . 54. SYMBOLS . 65. PREDICTION OF SINGLE STREAM JET MIXING NOISE FROM SHOCK-FREE CIRCULAR NOZZLES .
15、 85.1 Static Conditions 95.2 Flight Condition 105.3 References 125.4 Parties Contributing to Formulation of Section 5 . 126. PREDICTION OF SINGLE STREAM SHOCK-ASSOCIATED NOISE FROM CONVERGENTNOZZLES AT SUPERCRITICAL CONDITIONS . 486.1 Static Conditions 486.1.1 Overall Sound Pressure Level Prediction
16、 506.1.2 Angular Range of Application 526.2 Flight Conditions 526.3 References 536.4 Parties Contributing to Compilation of Section 6 . 537. PREDICTION OF SUBSONIC COAXIAL JET MIXING NOISE 537.1 Scope. 547.2 Development of the Coaxial Jet Noise Prediction Model 587.3 Component Sound Pressure Level P
17、rediction 597.4 Sound Pressure Level Adjustments in Prediction . 597.4.1 Normal Adjustments 597.4.2 Acoustic Excitation Adjustments . 607.5 Mixed Jet Noise Component . 607.6 Special Features 607.6.1 Near-Field Effects 617.6.2 Acoustic Excitation 627.6.3 Jet Noise Source Locations . 627.7 Incorporati
18、on of Distributed Source Location 637.7.1 Wind Tunnel Coordinates 637.7.2 Ground-Fixed Coordinates for Flyover Jet Noise 647.8 Predictions of Jet Noise Levels for Full-Scale Tests . 657.9 Prediction of Jet Noise Levels for Full-Scale Tests - Static or Flight (Section 7) 657.9.1 External Plug Effect
19、. 657.9.2 Ground Proximity Effect . 657.9.3 Installation and Angle of Attack Effects . 667.10 References 677.11 Parties Contributing to Formulation of Section 7 . 688. PREDICTION OF NOISE FROM CONVENTIONAL COMBUSTORS INSTALLED IN GAS TURBINE ENGINES. 688.1 Static Conditions 688.2 Flight Conditions 7
20、58.3 References 758.4 Parties Contributing to the Formulation of Section 8 . 759. NOTES 76SAE ARP876F Page 3 of 103 APPENDIX A BACKGROUND TO PREDICTION OF SINGLE STREAM JET MIXING NOISE FROMSHOCK-FREE CIRCULAR NOZZLES (SECTION 5) . 78APPENDIX B BACKGROUND TO PREDICTION OF SINGLE STREAM SHOCK-ASSOCIA
21、TED NOISEFROM CONVERGENT NOZZLES AT SUPERCRITICAL CONDITIONS (SECTION 6) . 90APPENDIX C BACKGROUND TO PREDICTION OF SUBSONIC COAXIAL JET MIXING NOISE . 97APPENDIX D BACKGROUND TO PREDICTION OF NOISE FROM CONVENTIONAL COMBUSTORSINSTALLED IN GAS TURBINE ENGINES (SECTION 8) 99FIGURE 1 11FIGURE 2 VARIAB
22、LE DENSITY INDEX Z 13FIGURE 3 CARPET PLOT FOR NORMALIZED OVERALL SOUND PRESSURE LEVELS OF PUREJET-MIXED NOISE . 14FIGURE 4 ADJUSTMENT FACTOR FOR NORMALIZED FREQUENCY . 15FIGURE 5 ONE-THIRD OCTAVE-BAND NORMALIZED SPECTRA TId 90 DEGREES 16FIGURE 6 ONE-THIRD OCTAVE-BAND NORMALIZED SPECTRA TI= 100 DEGRE
23、ES 18FIGURE 7 ONE-THIRD OCTAVE-BAND NORMALIZED SPECTRA TI= 110 DEGREES 20FIGURE 8 ONE-THIRD OCTAVE-BAND NORMALIZED SPECTRA TI= 120 DEGREES 22FIGURE 9 ONE-THIRD OCTAVE-BAND NORMALIZED SPECTRA TI= 130 DEGREES 24FIGURE 10 ONE-THIRD OCTAVE-BAND NORMALIZED SPECTRA TI= 140 DEGREES 26FIGURE 11 ONE-THIRD OC
24、TAVE-BAND NORMALIZED SPECTRA TI= 150 DEGREES 28FIGURE 12 ONE-THIRD OCTAVE-BAND NORMALIZED SPECTRA TI= 160 DEGREES 30FIGURE 13 VARIATION OF VELOCITY EXPONENT M(TI) WITH ANGLE TIAND JET MACH NUMBER VJ/AO. 32FIGURE 14 ESTIMATED RANGE OF UNCERTAINTY ASSOCIATED WITH CALCULATED VALUES OF OASPL (TI) FOR VA
25、RIOUS JET VELOCITY RATIOS AND UNCERTAINTY IN M(TI) . 33FIGURE 15 MASTER SPECTRA FOR SHOCK-ASSOCIATED NOISE PREDICTION 51FIGURE 16 SCHEMATIC COAXIAL JET NOISE MODEL IN WIND TUNNEL COORDINATES 58FIGURE 17A IN-FLOW COORDINATES . 64FIGURE 17B FLYOVER COORDINATES 64FIGURE 17 COORDINATE SYSTEMS FOR JET NO
26、ISE PREDICTION 64FIGURE 18 SCHEMATIC OF INSTALLATION PARAMETERS 67FIGURE 19 FLOW CHART FOR COMBUSTOR NOISE PREDICTION . 70FIGURE 20 SPECTRUM SHAPE FOR COMBUSTOR NOISE . 71FIGURE 21 FAIRFIELD DIRECTIVITY FOR COMBUSTOR NOISE . 72TABLE 1 VARIABLE DENSITY INDEX Z (REFERENCE FIGURE 2) . 34TABLE 2 PURE JE
27、T MIXING NOISE NORMALIZED POLAR OASPL (DB) VALUES(REFERENCE FIGURE 3) 35TABLE 3 ADJUSTMENT FACTOR FOR NORMALIZED FREQUENCY . 36TABLE 4 GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE d 90 DEGREES . 37TABLE 5 GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 100 DEGREES . 38TABL
28、E 6 GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 110 DEGREES . 39TABLE 7 GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 120 DEGREES . 40TABLE 8 GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 130 DEGREES . 41TABLE 9A GAS TURBINE JET EXHAUST NOISE PREDICTION
29、 TIANGLE TO INTAKE = 140 DEGREES . 42TABLE 9B GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 140 DEGREES . 43TABLE 10A GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 150 DEGREES . 44TABLE 10B GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 150 DEGREES . 45TAB
30、LE 11A GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 160 DEGREES . 46TABLE 11B GAS TURBINE JET EXHAUST NOISE PREDICTION TIANGLE TO INTAKE = 160 DEGREES . 47TABLE 12A RELATIVE VELOCITY EXPONENT M(TI)V 48TABLE 12B RELATIVE VELOCITY EXPONENT M(TI) 48TABLE 13 MASTER SPECTRA HO(V) AND C1(V
31、) . 52TABLE 14 JET NOISE COMPONENT FORMULAS 54SAE ARP876F Page 4 of 103 TABLE 15 NORMAL ADJUSTMENT (DSPL). 56TABLE 16 ACOUSTIC EXCITATION ADJUSTMENT (EX) . 57TABLE 17 SPECTRUM SHAPE FACTOR FOR COMBUSTOR NOISE . 73TABLE 18 FARFIELD DIRECTIVITY INDEX FOR COMBUSTOR NOISE 74SAE ARP876F Page 5 of 103 1.
32、SCOPE ARP876 is intended to provide specific recommended procedures for the prediction of gas turbine jet exhaust system noise sources. Procedures are issued as separate sections, to allow for future updating as additional methods, consistent with state-of-the-art, become available. 2. SOURCES OF EX
33、HAUST NOISE The exhaust system noise of gas turbine engines for aircraft applications can be considered to comprise the following main sources: a. Pure jet mixing noise resulting from a hot core exhaust stream mixing with its surrounding environment (which may be influenced by a bypass flow) b. Pure
34、 jet mixing noise resulting from a cold bypass stream mixing with both the surrounding environment and the core flowc. Shock associated noise, where either or both hot and cold exhaust systems comprise a choked final nozzle d. Noise from the core engine resulting from aerodynamic disturbances upstre
35、am of or at the final nozzle, including combustion noise. e. Aerodynamic noise, tonal and broadband, resulting from blade interaction effects in fan, compressor or turbine systems All the above sources combine in varying degrees to produce the overall exhaust noise characteristics. The relevance of
36、each source is a function of both engine operating condition and aircraft speed. Because of the dependence of aerodynamic blading noise on the intimate design configuration of any given engine, this aspect is specifically excluded from subsequent consideration, and every attempt has been made to rem
37、ove such phenomena from any engine data used.3. NOTES ON USE OF PREDICTION PROCEDURES 3.1 Prediction methods included in this document are self-contained. To develop an estimate of the total exhaust noise signature from an engine it is necessary to integrate the individual source components. This is
38、 effected by estimating each component spectrum and summing the energy in each one-third octave band. This is usually most conveniently carried out prior to any extrapolation to the relevant distance or corrections for atmospheric conditions and ground reflection effects. It is also necessary to inc
39、orporate any estimated turbo-machinery content (not covered herein) at the initial stage, in order to obtain a complete spectrum of engine noise. Furthermore, it is advisable that any assumed modification to the noise by virtue of suppression features or installation effects is made in the component
40、 calculation state. 3.2 Methods contained in this document are expressed in terms of noise levels that would be measured under free field conditions. Reflective augmentations and cancellations from real surfaces, primarily the ground surface over which measurements are made, produce peaks and trough
41、s in the observed test spectra, and these have been corrected out of the experimental data used where they have not been obtained under anechoic conditions. Spectra and directivity plots in this document must, therefore, be converted to non-free-field conditions to make them representative of typica
42、l measurements “in the field”. SAE AIR1327 provides guidance on such conversion for an acoustically hard surface (i.e., concrete, tarmac) and advice on how to deal with other typical surfaces (e.g., grassland). SAE ARP876F Page 6 of 103 3.3 The prediction methods provide spectral information derived
43、 from measurements taken in the acoustic far field, but corrected for loss due to atmospheric attenuation and normalized for distance. Since practical distances involved in aircraft noise calculations are large, apart from the normal inverse square law correction, allowance must be made for atmosphe
44、ric absorption. SAE ARP866A provides a standard method of allowing for atmospheric absorption under a range of ambient temperature and humidity conditions. 3.4 Prediction methods are directed at producing estimates of noise levels generated during the normal take-off and approach regimes of aircraft
45、 operation. Extrapolation of the methods to higher flight speeds, or use for estimation other than in the acoustic farfield, is not recommended since experimental evidence in support of such extrapolation was not available at the time of preparation of this document. 4. SYMBOLS aoAmbient speed of so
46、und m/s A Cross-sectional area of jet exhaust nozzle m2(with subscripts to define nozzle referred to) CvVelocity coefficient for relevant discharge nozzle DI Farfield directivity index dB D Exhaust nozzle diameter (with subscripts) m EXA (distance from fan face to fan duct exit)/(fan diameter) f Fre
47、quency Hz g Gravitational constant; 9.80665 m/s2ISA International Standard Atmosphere L Sound pressure level dB m(T1) Relative Velocity exponent used in converting static mixing noise to flight conditions M Jet Mach number Vj/ao)MaAircraft flight Mach number (Va/ao)n Jet velocity exponent N Rotation
48、al speed (with subscripts) rpm NPR Nozzle pressure ratio (Pj/Po)OAPWL Overall sound power level (re 1 pW) dB OASPL Overall sound pressure level (re 20 PPa) dB p Sound pressure Pa SAE ARP876F Page 7 of 103 poAmbient static pressure Pa pISAStatic pressure under ISA, sea level conditions Pa prefAcousti
49、c reference sound pressure, 20 PPa Pa P Total pressure Pa PoAmbient-total pressure Pa PISATotal pressure under ISA, sea level conditions PA PWL One-third octave-band sound power level (re 1 pW) dB r Radial distance from sound source (or nozzle exit) m to observer R Gas constant with value 287.05 J.kg-1K-1based on the J.kg-1K-1universal gas constant of 8.31432 x 103J/K(kg-mol) and mass per kilogram-mole in
