Acoustic attenuation analysis of oval expansion chambers with extended single inlet and double outlets

作者：Fang, Z.^*; Liu, C. Y.

来源：Noise Control Engineering Journal, 2017, 65(2): 83-93.

DOI：10.3397/1/376428

• OFFSET INLET/OUTLET
• TRANSMISSION LOSS
• NUMERICAL-METHODS
• SIDE-OUTLET
• PERFORMANCE

A numerical mode matching (NMM) approach is developed to predict the acoustic attenuation performance of expansion chambers with extended single inlet and double outlets, and validated by comparing the transmission loss predictions from the NMM, three-dimensional finite element method (FEM) and 1-D analytical method. Then the NMM method is used to investigate the effects of extended lengths of inlet and outlets as well as higher order modes on the acoustic attenuation performance. The results demonstrated that the side-branch resonance may be produced only when the two extensions of outlets are nearly equal. Choosing the extensions of inlet and outlets reasonably may eliminate the pass frequencies and yield a broad band acoustic attenuation. The expansion chamber with symmetric outlets about the minor axis exhibits better acoustic attenuation performance than that with non-symmetric outlets since the effects of some higher order modes may be eliminated by the symmetric outlets.

• 出版日期2017-4
• 单位华中科技大学; 中国舰船研究设计中心