穿孔管阻性消声器消声性能计算及分析

一维解析法和三维子结构边界元法被用于计算和分析穿孔管阻性消声器的消声性能，以及考查消声器内非平面波对消声特性的影响。直通穿孔管阻性消声器传递损失的预测结果与实验测量结果比较表明：一维解析法只适合于消声器的低频声学性能计算，对于高频声学性能的精确预测需使用三维计算方法。边界元法进而被用于研究吸声材料的填充密度（流阻率）和几何参数对穿孔管阻性消声器消声性能的影响。增加吸声材料的填充密度、穿孔管的穿孔率和穿孔长度、以及吸声材料的厚度，均能有效地改善阻性消声器的中高频声学性能，而对消声器的低频消声效果影响较小。

Acoustic attenuation performance prediction and analysis of perforated tube dissipative silencers

A one-dimensional analytical approach and a three-dimensional substructure boundary element approach are developed to predict and analyze the acoustic attenuation performance of perforated tube dissipative silencers,as well as examining the effect of nonplanar waves in the silencers in the acoustic attenuation characteristics.Comparisons of transmission loss predictions with experimental results for straight through perforated tube dissipative silencers illustrate that the three-dimensional approach is needed for accurate prediction and analysis at higher frequencies,while the one-dimensional analytical approach provides a reasonable accuracy at lower frequencies only.The boundary element method is then used to investigate the effects of bulk density of sound-absorbing material(or flow-resistivity) and geometrical parameters on acoustic attenuation performance of perforated tube dissipative silencers.Increasing the filling density of sound-absorbing material,the perforation porosity and length of perforated tube,and the thickness of sound-absorbing material may improve the acoustic attenuation performance of dissipative silencers at higher frequencies,while the effect on lower frequency performance is marginal.