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为揭示涡扇发动机分开排气式喷管喷流噪声的频谱分布和指向特性,对喷管缩比模型远声场喷流噪声进行了预测及试验研究,并开展了全尺寸喷管基准型及锯齿型喷流噪声的预测工作。结果表明:采用Tam&Auriault方法可以预测出喷流噪声的声压级值和空间指向分布,喷流噪声具有明显的指向性。与基准型喷管相比,锯齿型喷管具有良好的降噪效果;内外涵锯齿型喷管在中低频段的降噪效果优于内涵锯齿型喷管,在高频段的降噪效果差于内涵锯齿型喷管;在本文研究参数范围内,指向角小于88°时内外涵锯齿型喷管总声压级(OASPL)值高于内涵锯齿型喷管。
In order to reveal the spectral distribution and directional characteristics of the jet nozzle noise of the turbofan engine, the prediction and experimental research on the jet noise of the far-field nozzle was carried out. The full-scale nozzle reference and serrated Type jet noise prediction work. The results show that the sound pressure level value and spatial distribution of jet noise can be predicted by Tam & Auriault method, and jet noise has obvious directivity. Compared with the reference nozzle, serrated nozzle has a good noise reduction effect; the inner and outer serrated nozzle nozzle in the low frequency band noise reduction effect is better than the content serrated nozzle, the noise reduction effect in the high frequency band is worse than In the research parameter range of this paper, the OASPL value of serrated nozzle is higher than that of serrated nozzle when the directivity angle is less than 88 °.