空心管型泡沫铝吸声性能的数值模拟分析

Numerical simulation of sound absorption performance of hollow tube aluminum foam

为了提高多孔泡沫铝材料的吸声性能,将泡沫铝加工成空心管型结构。首先,利用声学阻抗管测试系统获取吸声系数;其次,基于JCA声学模型,采用COMSOL软件对空心管型泡沫铝进行仿真模拟以获取吸声系数,将吸声系数仿真结果与试验结果进行对比,验证仿真模型的可靠性;最后,通过声压云图和能量耗散云图对空心管型泡沫铝内部声场进行分析,并进一步通过数值模拟探究空心管参数对吸声性能的影响规律。研究结果表明:该空心管型结构属于共振式吸声结构;当声波的频率和结构中固有频率相同时,声波激励结构振动的振幅最大,导致大量的声能被消耗,从而起到吸声的作用;对于空心管型泡沫铝结构,可以通过增大空心管的半径、增加空心管的数量来提高吸声系数;在1000~6300 Hz的频率范围内,背后添加空腔的空心管型泡沫铝结构的平均吸声系数相较于背后添加空腔的均质型泡沫铝结构的平均吸声系数提高了26%。

In order to improve the sound absorption performance of porous aluminum foam,the aluminum foam was processed to form a hollow tube structure.The acoustic impedance tube test system was used to obtain the sound absorption coefficient.Based on the JCA acoustic model,COMSOL was used to simulate the hollow tube aluminum foam to obtain the sound absorption coefficient.The reliability of the simulation model was verified by comparing the simulation results with the experimental results.The internal sound field of the hollow tube aluminum foam was analyzed by the sound pressure filed and the dissipated power density,and the influence of hollow tube parameters on sound absorption performance was further explored by numerical simulation.The results show that the structure belongs to resonant sound absorption structure.When the frequency of sound wave is the same as the natural frequency of the structure,the amplitude of the vibration of the structure excited by sound wave is the largest,which will cause a lot of sound energy consumption and play the role of sound absorption.For the hollow tube aluminum foam structure,the sound absorption coefficient can be improved by increasing the radius of the hollow tube and the number of hollow tubes.The average sound absorption coefficient of the hollow tubular aluminum foam structure with cavity behind is 26%higher than that of the homogeneous aluminum foam structure with cavity behind in the frequency range of 1000~6300 Hz.