基于管道声模态的消声器传递损失计算

摘要

Transmission loss is an important index in evaluating muffler’s acoustic performance. A new method called acoustic mode of pipeline was proposed in this paper to estimate the transmission loss. This method was applied to the transmission-loss estimation in the muffler with narrow inlet and outlet. The result checks well with that of the traditional method, and the process is very simple. For the muffler with larger sectional areas of the inlet and outlet, the traditional method fails since large amount of high-order secondary wave appears in the medium-high frequency range. But in the low frequency range the result is consistent with that of the traditional method since the plane wave becomes the main acoustic wave in the pipeline. In this case, the method of acoustic mode in pipeline can estimate the transmission loss effectively.%传递损失是评价消声器声学性能的一个重要指标。提出了一种方法-管道声模态法代替传统方法估算传递损失。对进出口截面积较小的消声器进行计算和检验，与传统方法比较，结果基本吻合，且过程简单，提高传递损失的计算效率。对进出口截面积较大的消声器，中高频段由于大量高次波的出现，传统方法失效；但低频段管中声波以平面波为主，其结果与传统法一致。因此可以采用管道声模态法快速估算传递损失。