释压法混合吸声系统中多孔材料厚度优化研究

摘要

研究释压法主被动混合吸声结构吸声性能与多孔吸声材料参数的关系,利用释压法对材料厚度敏感的特性,选择合适的多孔材料厚度提高系统的低频吸声性能.提出一种释压法主被动混合双层吸声结构.将误差传声器置入两层吸声结构之间的空气层中,分别优化各层的厚度,在较宽频带内获得较好吸声.对流阻系数为15000 NSm-4的一类典型的玻璃棉数值仿真,发现选择优化厚度分别为2.8 cm和6 cm,中间空腔长为2 cm,可使有效吸声频带向下大幅扩展.实验结果验证了所提宽带吸声结构.%The relationship between the performance of hybrid pressure-release sound absorption structure and the parameters of porous materials is investigated and it is found that the pressure-release method is sensitive to the thickness of materials.So a proper thickness of porous material is selected to increase the low-frequency sound absorption performance of the system of interest.A novel hybrid pressure-release sound absorption structure is proposed,where the error microphone is located in the middle air gap between two layers of sound absorption structure, and the thicknesses of both layers of sound absorption material are optimized.For an example of typical glass wool with a resistivity coefficient of 15000NSm-4,our simulations show the low side of effective sound absorption frequency range can be significantly extended with the optimal layer thicknesses of 2.8 cm and 6cm, respectively, and with the length of the middle cavity of 2 cm.The experiment results validate the proposed broad band sound absorption structure.