多孔侧壁耦合亥姆霍兹共振器对吸声性能影响的数值仿真

Numerical simulation of the effects of coupled Helmholtz resonators with a multiple perforated sidewall on sound absorption performance

为了抑制船舶柴油机的进排气以及空调通风管路内的噪声,亥姆霍兹共振器通常被用作消声器来耗散声波。声学数值模型基于有限元方法,运用COMSOL5.3软件,对平行耦合型亥姆霍兹共振器在频域内建立模型,求解线性化的Navier-Stokes方程。通过仿真分析共振器侧壁穿孔率、孔的数量以及来流马赫数的变化对共振频率、传递损失以及吸声性能的影响。结果表明:穿孔率由25%增至50%时,能够拓宽消声频带和提高吸声性能;在固定穿孔率情况下,侧壁孔数的增加有益于提升共振器的吸声性能,特别是高来流马赫数工况(Ma≥0.07)比较明显。此外随着来流马赫数的增加,由于2个平行耦合的共振腔之间的共振作用,使得模型能产生3个及以上的共振频率。

In order to suppress the noise in the intake and exhaust of the diesel engine and in the air-conditioning ventil-ation pipeline on the ship,Helmholtz resonators are commonly used as mufflers to dissipate acoustic waves.It studies the parallel-coupled Helmholtz resonator commonly used in engineering.Based on the finite element method,an acoustic numer-ical model was established in the frequency-domain by using COMSOL5.3 software,which solves the linearized Navier-Stokes equations.The simulation analyzed the effects of the resonator in terms of the number of holes,perforation ratio and inflow Mach number on the resonance frequency,transmission loss,and sound absorption performance.It is shown that as the perforation rate is increased from 25%to 50%,it can widen the noise reduction frequency band and improve the sound absorption performance.In the case of a fixed perforation ratio,an increase in the number of sidewall holes is beneficial to improve the sound absorption performance of the resonator,especially in the case of high Mach numbers(Ma≥0.07).In ad-dition,the model can have three or more resonant frequencies due to the resonance effect between two parallel coupled res-onantcavities.