基于计算流体力学计算结果的穿孔管消声器声学性能研究

Acoustic Attenuation Performance of Perforated Tube Silencer Based on Computational Fluid Dynamics Results

为了准确研究温度与气体流动对某轿车穿孔管消声器声学性能的影响,建立消声器的结构模型与内部流体域模型,并分别划分流体域的计算流体力学(Computational fluid dynamics,CFD)网格与声学有限元网格。利用Fluent软件对消声器内部的温度场与气流速度场进行仿真计算。通过网格映射的方法,将CFD网格上温度、气流速度等数据转移到声学网格中,以CFD计算结果作为声场分析的边界条件,应用声学软件LMS Virtual.Lab Acoustics对消声器内部声场进行数值模拟,得到传递损失曲线。研究结果表明,介质温度升高使传递损失曲线向高频方向移动;存在气体流动时传递损失曲线向低频方向移动,传递损失也有所增加,尤其是在20~200 Hz的低频段内变化较为明显,但总体来看变化幅度不大。

To accurately study acoustic attenuation performance of a car perforated tube silencer under temperature and air flow influence, structural and fluid models are established, computational fluid dynamics （CFD） and acoustic finite element meshes are generated, respectively. CFD software Fluent is used to simulate and calculate temperature and velocity field of the silencer. Mesh mapping approach is employed to transfer CFD meshes with temperature and velocity dates to acoustic meshes. By using CFD results as boundary condition of acoustic field analysis, LMS Virtual.Lab Acoustics software is applied to carry out a numerical simulation on the internal acoustic field of the silencer and obtain its transmission loss curves. The results show that increasing air temperature shift transmission loss curve to higher frequency. The curve is moved to lower frequency as air flow exists and transmission loss is increased, especially within the low frequency brand between 20 Hz and 200 Hz these changes are visible, but overall the range is small.