航空发动机复合材料声衬声学模型构建及吸声性能仿真

Construction of acoustic model and simulation of sound absorption of aero-engine composite acoustic liner

声衬是降低发动机噪声的重要组件。本工作计算不同流场状态下管道模态声源特征,并以此作为Actran软件背景流场计算及声传播计算的输入边界,建立声传播模型,研究单自由度声衬与双自由度声衬消音板孔直径、孔间距、蜂窝高度和消音板厚度4种结构参数对吸声效果的影响规律。仿真结果表明:两种自由度声衬都表现出在一定孔直径范围内穿孔直径越小,吸声性能越好的现象;孔间距、蜂窝高度和消音板厚度对吸声性能的影响随频率变化;在2500 Hz以上双自由度声衬耗散功率较大,吸声效果好。通过在流管实验对比验证,比较不同结构声衬在不同激励源下的传递损失,得到合理可信的仿真方法。

Acoustic liner is an important component to reduce engine noise.In this work,the modal sound source characteristics of the pipeline under different flow fields were calculated and used as the input boundary for the background flow field calculation and sound propagation calculation of the Actran software,thereby establishing the sound propagation model.The influences of four structural parameters on the sound absorption effect of the muffler plate hole diameter,hole spacing,honeycomb height,and muffler plate thickness in the single-DOF acoustic liner and the double-DOF acoustic liner were studied respectively.The simulation results show that both degrees of freedom acoustic liners exhibit the phenomenon that the smaller the perforation diameter,the better the sound absorption performance within a certain range of hole diameter.The effects of hole spacing,honeycomb height,and muffler thickness on the sound absorption performance are varied with frequency,the double-DOF acoustic liner above 2500 Hz has large dissipation power and good sound absorption effect.Through the contrast verification in the flow tube test,the transmission loss of the acoustic liner of different structures under different excitation sources is compared,and a reasonable and credible simulation method is obtained.