进气噪声源提取和空滤器声学性能优化

测量了安装不同声学负载时某发动机的进气噪声.运用基于四负载的最小二乘法提取了进气噪声源，并计算安装某一负载时的进气噪声，与实验值进行对比.结果表明，在大部分频率范围内，仿真值与实验值吻合较好，说明提取的声源准确可靠.运用有限元方法计算原空滤器的声学特性，结合进气噪声源，计算安装空滤器时进气噪声的阶次成分，确定需要消声的频率点，通过增设和改进消声元件，达到了降噪的目的.

Extraction of Intake Acoustical Source and Optimization of Acoustic Performance of Air-cleaner

The intake noise of engine fixed with different acoustical loads was measured and the intake acoustical source was extracted using the four load least squares method. The calculated and experimental values of the intake noise when fixed with one load were compared. The comparison results show that at most of the frequency range, the simulation values agree well with the experimental ones, indicating that the acoustical source extracted is reliable. By taking into consideration the intake acoustical source and by culculating the acoustical characteristics of the original air-cleaner using the FEM approach, the order components of intake noise was computed. The frequencies where the noise needed to be lowered were found. Finally, the noise was reduced by adding or better designing noise eliminating elements.