工业消声器侧壁传声的预测方法与拟合公式

Flanking Transmission Prediction and a Fitting Equation for Industrial Mufflers

摘要: 大型工业消声器空气通道透射的声能量往往远小于侧壁振动二次辐射引起的噪声泄漏。本文基于圆形声波导理论给出一种消声器侧壁传声的预测方法。假设半无限长管道一端布置声源，利用模态分解法得到圆柱管壁外的声场，进而计算有限长管道侧壁的透射声功率和传递损失。在此基础上，综合考虑质量、结构环频和吻合频率的影响，结合解析方法得到的数据，拟合得到一个工程预报公式，可应用于典型工业消声器侧壁传声损失的快速估算。随后分析了侧壁传声对消声器插入损失的影响，对于实际的工业消声器，考虑侧壁传声后的插入损失与实测结果接近，验证了预测方法的可行性。

Abstract: The sound energy transmitted from the air passage of large industrial muffler is often much smaller than that from the flanking paths. In this paper, based on acoustic waveguide theory and commer-cial finite element tool, a prediction method of flanking sound transmission for a cylindrical muffler is proposed. Assuming that the sound source is arranged at one end of a semi-infinite-length pipe, the sound field outside the cylindrical pipe wall is calculated using the modal decomposition meth-od. Then the transmitted sound power and transmission loss are calculated for the side wall of the finite-length pipe. Considering the effects of mass, ring frequency and coincident frequency, com-bined with the data obtained from the analytical method, an engineering prediction formula is proposed that can be used to estimate the flanking transmission loss of a typical industrial muffler. Subsequently, the effect of sidewall sound transmission on the insertion loss of the muffler was an-alyzed, and the results showed that the insertion loss of the muffler is close to the measured results, which verifies the feasibility of the prediction method.