柔性背腔鼓型消声器声学特性分析

现有的鼓型消声器由具有刚性背腔的膨胀腔和张紧的薄膜构成,利用薄膜的振动辐射声场与原声场叠加作用,使得透射过消声器的声能减少,达到消声的目的。为使消声器兼具隔振作用,提出了新型柔性背腔鼓型消声器,基于Fourier-Galerkin方法建立其声学理论模型,将传递损失特性与现有的刚性背腔模型进行比较,进一步研究柔性背腔鼓形消声器的消声机理,并分析了背腔参数对性能的影响。计算结果表明,柔性背腔有效提高了消声器低频消声效果,较相同结构尺寸条件下的刚性背腔消声器,显著拓宽了有效消声带宽。

Acoustic characteristic of drum-like silencer with flexible back cavity

The existed drum-like silencer usually consists of expansion chamber with rigid back cavity (RBC) and tensioned membrane. With the effect of vibration radiation of the membrane, the transmitted acoustic energy can be reduced. In order to enable the silencer with ability of vibration isolation, a new type of silencer with flexible back cavity (FBC) was presented. The acoustic theoretical model was established using Fourier-Galerkin method. Then, the transmission loss (TL) characteristic was compared with the RBC model. Further, the silencing mechanism of the FBC silencer was studied, and the influence of the FBC parameters on the performance was also analyzed. The results indicate that the proposed FBC silencer has a better performance in low frequency. Compared with the RBC silencer having same structural size, the acoustic absorption band can be improved dramatically.