Abstract

The purpose of this work is to optimize the acoustic performance of low cost, simple geometry mufflers by using microperforated panels (MPP) in their expansion chambers. The Transmission Loss (TL) given by a computed model is compared with laboratory measurements, both for the mufflers containing the microperforated panels and without them. The optimization calculation is based on the easy computing transfer matrix approach. Then, the Boundary Element Method (BEM) is used in order to compare the evaluation of the TL. Different configurations have been tested so as to detect the real effect of resonator absorbers based on microperforated panels in the expansion chambers. It is shown that their presence increases the TL at certain frequencies if their parameters are well chosen, but their dissipative effect is negligible when occurs at a reactive effect resonance. Thus, the MPPs can be an alternative to improve the TL for low frequencies when the reactive effect of the mufflers decreases.