渐变截面背腔微穿孔管消声器声传递特性分析

为提高微穿孔管消声器的性能,研究了背腔结构对消声器性能的影响。基于一维声传播理论和微穿孔结构吸声理论,推导了渐变截面背腔微穿孔管消声器的声传播理论模型,利用传递矩阵法求出声学传递损失,并将理论计算结果与有限元仿真分析结果进行了比较,在等容积条件下分析了结构参数对传递损失的影响。结果表明:微穿孔管消声器的传递损失曲线在背腔的轴向模态频率处有极小值;对于锥形体结构背腔,增加锥度能够拓宽吸声频带,提高背腔轴向共振频率处的极小值;对于弧形体结构背腔,减小弧形半径能够提高消声器的低频处的吸声效果。

Theoretical analysis on the transmission loss of a micro-perforated tube muffler with gradually changed back cavity

In order to improve the performance of a micro-perforated tube muffler (MPTM),the influence of cavity structure on the transmission loss of the MPTM was discussed.The acoustic transmission model for gradually changed back cavity micro-perforated tube muffler (GCBCMPTM) was established based on the one-dimensional plane wave theory and micro-perforated absorption theory.The transmission loss (TL) of the GCBCMPTM was solved with the transfer-matrix method.The calculated values were compared with the three-dimensional finite element model (FEM) acoustic simulation results.The influence of structure parameters of the back cavity on the TL was analyzed.The results show that minimums of the TL curve appear at the axial acoustic mode frequencies.For conical back cavity,when the taper increases,the absorption bandwidth will be expanded,and the values of minimums at the axial mode frequencies will be raised as well;while,for circular arc back cavity,when the radius of curvature decreases,the absorption bandwidth will be expanded,and the absorption effects in low frequency will be improved as well.