This paper describes a duct mounted with multiple hybrid Helmholtz resonators (HHRs) for low-frequency noise control in a piping system. The newly designed HHR is composed of a cavity and a connective neck with a coupling membrane and a perforated plate. Based on the transfer matrix method and equivalent mass-spring model of the membrane, the acoustic impedance of the HHR can be obtained. Sound radiation performance of the unit cell is carefully investigated using a numerical simulation method. Besides, the transmission loss (TL) and bandgap behavior of finite and infinite pipe can be evaluated, respectively. All the theoretical results are verified with corresponding numerical simulation. It is shown that, compared with traditional HR (THR), the HHR exhibit superior TL performance in the low-frequency region, and the energy radiated through the membrane at the first-order resonant frequency is relatively small. Damping caused by the perforated plate has a considerable impact on both the TL and band structure of the periodic pipe. The underlying physical mechanism is then revealed in combination with acoustic modes in the band structure. Additionally, the effect of the perforated plate on the bandgap coupling characteristics is also examined. Eventually, experimental study is also carried out to validate the acoustic performance of the HHRs. Summarizing, this study provides new insights into noise elimination in periodic piping systems.

本文介绍了一种安装有多个混合亥姆霍兹谐振器 (HHR) 的管道，用于管道系统中的低频噪声控制。新设计的 HHR 由腔体和带有耦合膜和穿孔板的连接颈部组成。基于膜的传递矩阵法和等效质量-弹簧模型，可以获得HHR的声阻抗。使用数值模拟方法仔细研究了晶胞的声辐射性能。此外，可以分别评估有限和无限管道的传输损耗 (TL) 和带隙行为。所有的理论结果都经过相应的数值模拟验证。结果表明，与传统的 HR (THR) 相比，HHR 在低频区域表现出优异的 TL 性能，并且在一阶共振频率下通过膜辐射的能量相对较小。穿孔板引起的阻尼对周期管的 TL 和带状结构都有相当大的影响。然后结合能带结构中的声学模式揭示潜在的物理机制。此外，还检查了穿孔板对带隙耦合特性的影响。最后，还进行了实验研究以验证 HHR 的声学性能。总而言之，这项研究为周期性管道系统中的噪声消除提供了新的见解。然后结合能带结构中的声学模式揭示潜在的物理机制。此外，还检查了穿孔板对带隙耦合特性的影响。最后，还进行了实验研究以验证 HHR 的声学性能。总而言之，这项研究为周期性管道系统中的噪声消除提供了新的见解。然后结合能带结构中的声学模式揭示潜在的物理机制。此外，还检查了穿孔板对带隙耦合特性的影响。最后，还进行了实验研究以验证 HHR 的声学性能。总而言之，这项研究为周期性管道系统中的噪声消除提供了新的见解。