YAN Guo-hua 1，2 ，FENG Shu-yang 1 ，LIU Yong1，LI Jian-fu 3.Numerical Calculation of Engine Jet Noise Based on Mohring Acoustic Analogy[J].航空发动机,2023,49(1):53-61
Numerical Calculation of Engine Jet Noise Based on Mohring Acoustic Analogy
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Key Words:separate exhaust nozzle  high subsonic jet  Large Eddy Simulation（LES）  Mohring sound analogy  jet noise  aeroengine
Author NameAffiliationE-mail
YAN Guo-hua 1，2 ，FENG Shu-yang 1 ，LIU Yong1，LI Jian-fu 3 1.School of Aeronautical Engineering，Civil Aviation University of China，Tianjin 300300，China；2. Basic Experiment Center Civil Aviation University of China，Tianjin 300300，China；3. Second Military Representative Office of Air Force Equipment Department Stationed in Shenyang Area, Shenyang 110043,China l1318959285@163.com 
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Abstract:In order to study the characteristics of aeroengine jet noise in a non-uniform flow field，and meet future aircraft noise air? worthiness requirements，a hybrid numerical algorithm combining Computational Fluid Dynamics（CFD）and Computational Aeroacoustics （CAA）was adopted. The simplified scale model of a large bypass ratio engine nozzle was calculated by the aerodynamic noise simulation method. The transient jet flow field of the nozzle was calculated using the LES（Large Eddy Simulation）method. Based on the flow field cal? culation，the sound source was extracted using the Mohring sound analog. The time-averaged flow field and its smooth interpolation were introduced to the acoustic grid as a background flow field. The near-field and far-field radiation characteristics of jet noise were numerical? ly calculated and analyzed by combining finite element and infinite element methods. And the feasibility of the numerical calculation meth? od was verified by the single-channel Chevron nozzle experiment. The numerical results show that engine jet noise is formed by large-scale vortices generated by the breaking of vortex rings in the inner and outer bypass shear layers. The peaks of noise radiation are concentrated in the low-frequency range. With the increase of frequency，the sound pressure level in each direction is decreasing，from 125 dB to 105 dB at 1000 Hz to 2500 Hz，and then the attenuation rate slows down and becomes stable at 100 dB. The numerical calculation method has high accuracy and the maximum calculation error is 1.97%，which can provide a noise prediction method for engine noise airworthiness certification.
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