Analysis of pressure loss and transmission loss under flow field effects in multi-chamber muffler

Abstract

Abstract In order to achieve broadband sound attenuation, a muffler utilizes multiple internal impedance structures, which unavoidably impacts its aerodynamic performance. Multi-chamber muffler configurations, incorporating interconnecting tubes, perforated plates, and other sound-absorbing elements, can generate several resonance peaks within the frequency range of sound attenuation, showcasing effective sound attenuation capabilities. These configurations are commonly employed in marine muffler structures. This paper examines the factors influencing the flow field performance of such mufflers and the impact of the internal flow field on their acoustic performance by using principles of fluid mechanics and the finite element method of acoustics. Initially, a flow field domain model of the multi-chamber muffler is developed by using the 3D modeling software SOLIDWORKS, and the mesh division of the flow field is executed by using the FLUENT MESHING preprocessing software. Subsequently, the mesh model is employed to simulate the flow field performance in the ANSYS Fluent environment, calculating the pressure loss of various structural mufflers under different inlet flow boundary conditions. Finally, field data is imported into the LMS Virtual. Lab software to validate the correlation between the flow field network and the acoustic field network, enabling the mapping of flow field data to simulate the silencer’s acoustic performance under different flow field conditions. The study demonstrates that a well-designed arrangement of interconnected pipes and perforated elements inside the silencer can notably diminish its pressure loss. Furthermore, it highlights that the impact of a temperature gradient on the silencer’s acoustic performance is more significant compared to the local flow rate.