A novel labyrinth-type structure enhancing sound insulation properties with acoustic black hole and Herschel-Quincke tube principles

This study proposes a labyrinth-type structure integrating acoustic black hole (ABH) and Herschel-Quincke (HQ) tube principles to achieve noise reduction without compromising ventilation capabilities. The structure directs sound waves toward the ABH outlet through a geometrically tailored profile before channeling them into a labyrinth loop. Locally interconnecting the labyrinth loops forms an HQ tube. To investigate the noise reduction mechanism, a theoretical model was developed using the transfer matrix method, and a numerical simulation was performed via the finite element method. To validate the theoretical and numerical models, a prototype was fabricated with 3D printing technique, and impedance tube experiment was conducted. The results indicate that the ABH enhances the structure’s noise reduction capability, while the HQ tube efficiently attenuates low-frequency noise. Parametric analysis demonstrated that structural modifications-including ABH wall curvature, ABH outlet radius, and HQ tube length-significantly influence noise reduction performance and effective frequency range. Experimental results exhibited excellent agreement with numerical simulation, confirming the design effectiveness. This innovative labyrinth-type structure provides a viable solution for noise control in industrial applications requiring concurrent ventilation and acoustic attenuation.