消声器传递损失预测的边界元模态展开混合方法

Transmission loss prediction of silencers by using combined boundary element method and modal expansion approach

将边界元法和解析方法结合形成一种混合方法用于计算消声器的传递损失,消声器被划分成若干个子结构,解析方法和边界元方法被分别用于计算规则结构和不规则结构的阻抗矩阵,不同子结构之间通过阻抗矩阵连接起来。为减少计算时间,采用一种基于模态配点法的简化方法。对单级膨胀腔、双级膨胀腔和穿孔管阻性消声器的传递损失进行了计算,混合方法计算结果与解析方法和三维数值方法计算结果吻合良好。分析了混合方法的计算效率并与传统子结构方法进行了比较,混合方法能明显节省计算时间。

A technique combining the boundary element method （BEM） and analytical approach is proposed to calculate the transmission loss of silencers. The silencer is divided into several substructures, the BEM and the analytical approach are employed to evaluate the impedance matrices of substructures with irregular and regular shapes, respectively, and then the impedance matrices for all substructures are related. In order to reduce the computational time, a technique based on modal meshing approach is adopted. The transmission loss predictions of single expansion chamber, double expansion chamber and perforated tube absorptive silencer from the present approach agree well with three-dimensional numerical predictions and analytical solutions. The computational efficiency is analyzed and compared with the traditional substructure approach. The combined approach may save computational time efficiently.