穿孔元件在管道消声装置中广泛使用，用于改善特定频率范围内的消声性能以及降低流动阻力损失。为精确预测管道消声装置的消声性能，首先需要获得穿孔元件的声阻抗。由于穿孔附近的流场和声场复杂，且存在流声耦合和非线性效应，因此获取气体流动状态下穿孔元件的声阻抗成为一项具有工程应用价值和理论意义的研究课题。本项目拟使用三维时域CFD方法作为计算工具，通过模拟计算施加在稳态流基础上的脉冲信号的传播过程来获取穿孔元件两侧的压力和速度时域历程，然后通过FFT变换得到相应的频域信号，进而结合声学理论提取出穿孔声阻抗。基于计算结果，分析介质温度、流动状态、穿孔形状、吸声材料等对穿孔声阻抗的影响规律，整理出适用于频域声学计算的穿孔声阻抗表达式。本项目的特点是能够考虑复杂气体流动和大幅波非线性效应对穿孔声阻抗的影响，从而获得精确的计算结果。为验证计算方法和结果的正确性，开展有流条件下穿孔元件声阻抗的实验测量研究。

The perforated components are widely used in the duct silencing devices to improve the acoustic attenuation performance in special frequency range and to reduce the flow resistance loss. In order to predict accurately the acoustic attenuation performace of duct silencing devices, the acoustic impedance of perforated compenents needs to be obtained first. In view of the complex sound and flow fields near the perforates, as well as the existence of flow-acoustic coupling and non-linear effect, the determination of perforate impedance in the presence of gas flow became an important project with engineering applications and theoretical significance. The present work will employ the 3-D time-domain CFD approach as the computational tool, the time histories of pressures and velocities in the both sides of the perforated component are aquired through the simulation of propagation of a pulse signal enforced on the steady flow, then the corresponding frequency-domain signals are obtained by using FFT, and finally the perforate impedance are extracted with the acoustic theory. Based on the computational results, the effects of medium temprature, flow status, perforated structure and sound-absorbing material on the acoustic impedance of perforates are analyzed, and then expressions for acoustic impedance of perforates are proposed suitable for the frequency-domain computations. The advantage of the project is that the effects of complex gas flow and non-linear behavior of large amplitude wave on the acoustic impedance of perforates may be considered, therefore the accurate results are obtained. To verify the computational method and results, the experimental measurements will be conducted in the presence of gas flow.