吸声层特性与布置对导管声辐射的影响

摘要

Sound radiation of a finite duct with absorber is studied by a method based on NASTRAN infinite element technology.The influence of absorber′s impedance,location and distribution on sound radiation of duct is analyzed.The results show that the absorber′s resistance value has significant in-fluence on the radiated power of duct while reactance value has little.It is equally efficient for the re-duction of total radiated power to locate the absorber near source or duct exit,but locating the absor-ber near exit is more beneficial for lateral shielding.Besides,it is not always acceptable to use an asymmetric absorber for the noise reduction at special angles.It depends on the frequency band.%采用基于 NASTRAN无限元技术的导管声学计算方法，对敷设吸声层的有限长导管声辐射特性进行了研究，讨论了吸声层阻抗值、布置位置和方式对导管声辐射的影响。结果表明：吸声层的声阻值对导管辐射声能量影响较大，而声抗值影响较小；将吸声层布置在近声源段或者出口段对于降低总辐射声能量的效果相当，但在出口段布置吸声层更有利于导管发挥侧方屏蔽效应；采用不对称式吸声层对于降低声功率和特定方向上的声压级并无绝对好处，需视频段具体分析。