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

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.