消声器传递损失计算的单元能量叠加法

在消声器进出口管道平面波截止频率以上,高阶模态被激发,传统方法假设进出口为平面波计算消声器传递损失的方法已不再适用。基于有限元法,把进出口面划分出若干个单元,将每个单元上的声场分布近似为平面波,建立基于单元能量叠加计算消声器传递损失的方法,并使用本文方法和Virtual.Lab Acoustics软件计算了三种类型消声器的传递损失,分析了非平面波现象。结果表明,本文方法可行且能够有效地考虑非平面波的影响。

Element Energy Superposition Method for Transmission Loss Prediction of Silencers

Above the plane wave cut-off frequency of the silencer inlet and outlet pipes, the higher order modes are excited, therefore the tranditional method to calculate the transmission loss of silencer is no longer applicable, which assumes the plane wave propagates in the inlet and outlet pipes. In the present paper, by using the finite element method, the inlet and outlet surfaces are divided into several elements, and the sound field distribution on each element is approximated as plane wave, then the predictive method of calculating the transmission loss of the muffler is established based on the element energy addition. Three kind silencers are chosen to calculate the transmission loss by using the present method and Virtual Lab Acoustics, and the non-plane wave behavior is analyzed. The results showed that the present method is feasible and may consider effectively the influence of non-plane wave.