The Impact of Microcellular Structures on the Sound Absorption Spectra for Automotive Exhaust Performance Mufflers

Abstract

The role of microcellular structures on the sound absorption spectra of packed structures for automotive exhaust performance mufflers are presented herein, via numerical modelling and simulation. Numerical simulations involving the application of Attenborough’s empirical model are demonstrated to be a better predictor for the sound absorption properties for packed beds of near-spherical structures, with reasonable scatter, when compared to experimental data substantiated in contemporary literature. By varying the packing arrangement for packed samples and stacking with differential microcellular structures, improvements in the absorption properties were achieved – thereby highlighting the dependence of propagated pressure waves on the structural configuration, positioning and thickness of soundproofing materials. This approach could assist in the implementation of microcellular structures in reducing unwanted engine noise, reduction in packing weight and improved active product lifetime of miniaturized soundproofing package in automotive exhaust performance mufflers.