膨胀腔消声器声学仿真的一维修正方法

Corrected one-dimensional approach for the acoustic simulation of expansion chamber silencer

传统一维方法计算消声器声学性能随频率增加误差加大,本文应用管道末端修正系数改善一维方法的计算结果。应用二维轴对称解析方法计算管道末端修正系数,研究结构因素和频率对修正系数的影响规律,研究表明修正系数随截面半径比增加而降低,随频率增加而增加,超过截止频率后修正系数无效。根据计算结果给出修正系数拟合公式并修正传统一维方法,应用一维修正方法计算膨胀腔消声器的传递损失并和实验结果、三维有限元结果进行比较,证明一维修正方法结果精度有明显提高。

The error in acoustic performance calculation of silencers with the traditional one-dimensional （ID） approach increases with the growing of frequency, thus, the end corrected coefficient of duct was used to improve the accuracy of the ID result in present paper. The two-dimensional axisymmetric analytical approach was developed to calculate the end correction coefficient and the effect of geometry factor and frequency on the end correction coefficient was studied. The end correction coefficient decreases with the increase of radii ratio and grows with the increase of frequency. The end correction coefficient is invalid for the frequency above the cut-off frequency. Based on the results, a fitting expression was obtained for the end correction coefficient and then employed to correct traditional ID approach. Using the corrected ID approach, transmission loss of expansion silencer was calculated and compared with experimental measurement and finite element method （FEM） result. The comparisons showed that the results accuracy of corrected ID approach was improved greatly.