具有并联不等深度子背腔序列的微穿孔板吸声体吸声特性

Absorption characteristics of micro-perforated panel sound absorbers with array of parallel-arranged sub-cavities with different depths

详细讨论了一种新型宽频带微穿孔板(MPP)吸声体的吸声特性,该吸声体由单层MPP和基于二次余数扩散体(QRD)深度序列设计的多个并联且深度不等的子背腔组成.首先,从理论上提出了该吸声体正入射吸声系数的解析计算方法;然后,建立了有限元数值仿真模型验证所提出的解析计算方法,并分析该吸声体的正入射吸声特性;最后,在矩形驻波管内基于传递函数法实验测量了该吸声体样品的正入射吸声系数.实验结果表明,所提出的该类吸声体正入射吸声系数的解析计算方法准确可靠.同时,在460~3 500 Hz的频率范围内,采用解析计算方法预测的该类MPP吸声体的正入射吸声系数不小于0.5,最大吸声系数能达到0.98.

A new prototype of micro-perforated panel(M PP)sound absorber with supposed high sound absorption property in a wide frequency band is discussed.This kind of sound absorber included a single layered MPP and several cavities with different depths based on the depth sequence designed of the quadratic residue diffuser(QRD).First,an analytical method for evaluating the normal incidence absorption coefficients of this kind of absorber is presented.Secondly,the analytical method is validated by the simulations with the finite element method and the normal incidence absorption characteristics of the absorber are investigated as well.Finally,the corresponding experimental study is carried out,in which the normal incidence absorption coefficient of a prototype absorber is measured in a rectangular standing wave tube by the transfer function method.The experimental results show that the proposed analytical method is accurate and reliable.Besides,the normal incidence sound absorption coefficient of this kind of MPP absorber predicted by the analytical method is not smaller than0.5over the frequencies from440to3500Hz,and the maximum sound absorption coefficients is0.98.