Abstract: A certain type of car exhaust muffler is taken as the object to research the acoustic performance. The muffler is divided into basic silencing units based on the transfer matrix method , and silencing units are analyzed to get muffler’s total transfer matrix , and its acoustic model is established. The frequency characteristic of transmission loss is calculated using Matlab software. Finite element simulation software , Sysnoise and Fluent are used for the simulation calculation to get the accurate frequency characteristic of transmission loss. The results obtained with both methods are compared to verify the accuracy of the acoustic model ,and the basis for improvement and optimization of the muffler is provide.

摘要： 以某型号的汽车排气消声器为对象，研究其声学性能。由传递矩阵法划分消声器的基本消声单元，并分析消声单元的传递矩阵，得到消声器总的传递矩阵，从而建立该消声器的声学模型。应用Matlab软件编程计算得到消声器的传递损失频率特性。应用有限元仿真软件Fluent和Sysnoise对消声器进行仿真计算，得到准确的传递损失频率特性。通过比较两种方法得到的结果，验证基于传递矩阵法建立的声学模型的准确性，为消声器的优化和改进提供依据。

关键词: 声学, 排气消声器, 传递矩阵, 传递损失, 消声单元, 声学模型