Abstract:

Transmission loss is an important index in evaluating muffler’s acoustic performance. A new method called acoustic mode in pipeline instead of the traditional method was proposed in this paper to estimate transmission loss. It was applied in the muffler with the smaller sectional area on the inlet and outlet whose result is nearly correct and the process is very simple compared with the traditional method, improving the efficiency in computing the transmission loss. For the muffler with the larger sectional area on the inlet and outlet, because of amount of high secondary wave appears in the medium-high frequency, the traditional method has become invalid; but in the low frequency the result is consistent with the traditional method for the plane wave is the main acoustic wave in the pipeline. So the method of acoustic mode in pipeline can estimate the transmission loss at express speed.

摘要：

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。

关键词: 声学, 传递损失, 消声器, 管道声模态, 高次波