穿孔板的声学厚度修正

使用有限元法计算穿孔板的声学厚度修正系数,研究穿孔率、穿孔板厚度、孔径和穿孔排列形式对声学厚度的影响,获得了穿孔率低于40%的穿孔板的声学厚度修正系数。计算结果表明:穿孔板厚度、孔径和排列形式对声学厚度的影响不大;穿孔率对声学厚度影响很大。基于数值计算结果给出了声学厚度修正系数的近似表达式,利用由该表达式形成的穿孔声阻抗公式计算了穿孔管消声器的传递损失,计算结果与实验结果吻合良好,从而验证了应用该表达式预测穿孔管消声器消声性能的准确性。

The acoustic thickness correction of perforated plate

The acoustic thickness correction coefficients of perforated plates are calculated using the finite element method (FEM).The effects of perforation porosity,plate thickness,hole diameter and pattern on the acoustic thickness are studied,and the acoustic thickness correction coefficients of perforated plates with porosity lower than 40% are determined.The results show that the influences of the plate thickness,hole diameter and pattern on the acoustic thickness are small,while the perforation porosity influences the acoustic thickness a lot.Based on the calculated results,an approximate expression is provided for the acoustic thickness correction coefficient of perforated plate.The transmission loss of perforated tube silencers is predicted by using the perforate acoustic impedance formed from the present approximate expression,and the numerical predictions agree well with the experimental results.The agreement shows that the present expression is valid for the acoustic performance predictions of perforated tube silencers.