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在消声室内的喷流噪声实验台上,对大涵道比涡扇发动机混合式排气系统缩比模型进行了冷喷流噪声实验,以环形混合器为基准,研究了采用波瓣混合器的喷管喷流远声场频谱特性和降噪效果.研究结果表明:与采用环形混合器的基准型喷管相比,波瓣混合器喷管在低频段有很好的降噪效果但高频段的声压级有所升高,波瓣混合器喷管下游方向(θ=150°)的总声压级明显降低而中游方向和上游方向的总声压级升高.随着波瓣混合器出口处内外涵气流速度差的增大,波瓣混合器喷管低频段的降噪效果越来越明显但高频段声压级的升高也会不同程度地增大,在波瓣混合器喷管下游方向(θ=150°)的总声压级降低更加明显的同时中游方向和上游方向的总声压级也有所升高.
In the anechoic chamber of the jet noise experiment platform, the large bypass ratio turbofan engine hybrid exhaust system contraction ratio model was carried out a cold jet noise experiment to ring mixer as a benchmark, studied the use of lobe mixer The results show that the lobe mixer nozzle has a good noise reduction effect in the low frequency band compared with the reference nozzle with a ring mixer, but the high frequency band The total sound pressure level in the downstream direction of the lobe mixer nozzle (θ = 150 °) is significantly reduced while the total sound pressure level in the middle and upstream directions is increased. As the lobe mixer At the outlet, the velocity difference between the inner and outer air flow increases. The noise reduction effect of the lobe mixer nozzle in the low frequency band becomes more and more obvious. However, the increase of the high frequency sound pressure level also increases to some extent. The total sound pressure level reduction in the downstream direction of the tube (θ = 150 °) is more pronounced, while the total sound pressure level in the middle and upstream directions also increases.