Study on the Acoustic Performance of Expansion Muffler Based on Comprehensive Analysis of Acoustic Modal and Transmission Loss

To study the relevance between the structure factor and the acoustic performance of the expansion muffler from the perspective of three-dimensional acoustical theory, the comprehensive analysis method of acoustic mode and transmission loss is used in this paper. The diameter and length of the expansion muffler, the diameter and length of the insertion pipe, and the position of the insertion pipe on the shell are selected as the structure factors of the study. Then a reasonable research program of the structure factors is developed, in which the selected structure factors are regularly changed, and the acoustic mode and transmission loss of each program are simulated. Based on the three-dimensional acoustic theory, the result contrast between the acoustic mode and the transmission loss is analyzed, and the change rule between the structure factor and the acoustic mode and the transmission loss is obtained. Finally, the study on the acoustic performance of expansion muffler is accomplished. The studies have shown that frequencies and modes of the acoustic mode of the different structure factors are necessarily related to the frequency and sound pressure level of the transmission loss.