Bai Yang, Chen Yuehua, Zheng Jiahui
Faculty of Maritime and Transportation, Ningbo University, Ningbo, 315000, China.
Sci Rep. 2024 Nov 22;14(1):28921. doi: 10.1038/s41598-024-79762-9.
To enhance the low-frequency sound absorption capabilities of expansion chamber mufflers, a novel Helmholtz-ring phononic crystal cell was developed. This innovative design integrates ring Helmholtz resonators as the phononic crystal scatterer, which is periodically arranged within the expansion chamber of a muffler to achieve enhanced sound attenuation at deep sub-wavelength scales. The transmission loss characteristics of the phononic crystal muffler were thoroughly examined and found to reveal a pronounced enhancement in sound absorption within the low-frequency bandgap. A critical aspect of this study was the analysis of the influence of defect states on transmission loss of the muffler. The introduction of defect states significantly expanded the sound attenuation bandwidth, effectively compensating for reduced sound absorption performance of the muffler outside the bandgap. The proposed phononic crystal muffler demonstrated a marked improvement in both transmission loss and aerodynamic performance compared to the traditional expansion chamber muffler. Notably, the sound attenuation was further augmented when in defective states. Corresponding experimental investigations were conducted and confirmed the effectiveness of the phononic crystal muffler within its designated bandgap range. This research presents a new way for the development of more efficient noise control solutions.
为了增强扩张室消声器的低频吸声能力，开发了一种新型亥姆霍兹环声子晶体单元。这种创新设计将环形亥姆霍兹谐振器作为声子晶体散射体，周期性地排列在消声器的扩张室内，以在深亚波长尺度上实现增强的声衰减。对声子晶体消声器的传输损耗特性进行了全面研究，发现在低频带隙内吸声有显著增强。本研究的一个关键方面是分析缺陷态对消声器传输损耗的影响。缺陷态的引入显著拓宽了声衰减带宽，有效补偿了消声器在带隙外吸声性能的降低。与传统扩张室消声器相比，所提出的声子晶体消声器在传输损耗和空气动力学性能方面都有显著改善。值得注意的是，在缺陷状态下声衰减进一步增强。进行了相应的实验研究，证实了声子晶体消声器在其指定带隙范围内的有效性。这项研究为开发更高效的噪声控制解决方案提供了一种新方法。
