切向流作用下单层声衬噪声阻尼性能的数值研究

Numerical Investigation of the Acoustic Damping Effect of Single-layer Acoustic Liner under the Action of Grazing Flow

孔隙率是影响声衬噪声阻尼特性的主要结构参数,在声衬结构优化方面起到关键作用。首先,基于由一系列8个完全相同的狭缝赫姆霍兹谐振器组成的单层声衬模型,利用COMSOL Multiphysics软件研究切向流作用下单层声衬在不同孔隙率下的传输损失,然后优化设计一种双层声衬,并与单层声衬的吸声性能进行比较,通过数值结果与文献实验测量结果对比验证,讨论孔隙率、切向流及层数对声衬阻尼性能的影响。结果表明:相较于无流情况,切向流存在时,随着孔隙率的增加单层声衬的吸声能力逐渐增强,噪声衰减主要发生在共振频率附近,同时切向流作用也会降低声衬产生的传输损失、改变共振频率,双层声衬的优势在于明显拓宽消声频率范围。研究成果为今后实际应用中声衬的优化设计提供了一种可预测方法。

Porosity is the main structural parameter that affects the noise damping characteristics of the acoustic liner,and plays a key role in the optimization of the acoustic liner structure.In this paper,a single-layer acoustic liner model composed of eight identical slit Helmholtz resonators is established.The transmission loss of the single-layer acoustic liner with different porosities under the grazing flow is investigated by using COMSOL Multiphysics code.Then,a double-layer acoustic liner is optimally designed and its sound absorption performance is compared with that of the single-layer acoustic liner.The effects of porosity,grazing flow and the number of layers on the damping performance of the acoustic liner are discussed by comparing the numerical results with the experimental results in the literature.The results show that under the action of grazing flow,the sound absorption performance of the single-layer acoustic liner gradually increases with the increase of porosity,the noise attenuation mainly occurs near the resonance frequency,and the grazing flow effect also reduces the transmission loss of the acoustic liner and changes the resonance frequency.Using double-layer acoustic liner can significantly broaden the range of anechoic frequency.This work provides a predictable method for optimizing the design of acoustic liner in future practical applications.