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利用位于全消声室中的喷流噪声实验台研究了V形槽喷管在分开式排气系统中的降噪特性,比较了在剪切速度比为0.92工况下V形槽喷管的结构参数以及分布方式在冷喷流中对降噪效果的影响.结果表明:V形槽喷管降低了低频段的喷流噪声并增大高频段的喷流噪声;在喷管的下游方向有最好的低频段降噪效果,并具有最小的高频段喷流噪声增加量;增大V形槽喷管切入角可以增加低频段的降噪量,其降噪量最高为5dB;仅在外涵添加V形槽喷管可以增大低频段的降噪量并抑制高频段的喷流噪声的增加;V形槽喷管齿数的变化对降噪效果有一定的影响,但其影响远小于切入角的变化对降噪效果的影响;另外V形槽喷管可以显著地降低喷管下游方向的声压级大小.
The noise reduction characteristics of the V-groove nozzle in a separate exhaust system were studied by using a jet noise experimental station located in a full anechoic chamber. The comparison of the noise reduction characteristics of the V-groove nozzle at a shear rate ratio of 0.92 Structure parameters and distribution in the cold jet were studied.The results show that the V-shaped nozzle reduces the jet noise in the low frequency band and increases the jet noise in the high frequency band, The best low-frequency noise reduction effect, and has the smallest increase in high-frequency jet noise; increase the V-groove nozzle angle can increase the amount of low-frequency noise reduction, the maximum noise reduction of 5dB; only in the external V-groove nozzle can increase the amount of noise reduction in the low frequency band and restrain the increase of the jet noise in the high frequency band. The change of the number of V-groove nozzle has some influence on the noise reduction effect, Of the impact on the noise reduction effect; another V-groove nozzle can significantly reduce the direction of the nozzle downstream of the sound pressure level.