Experimental study of acoustic performances of reactive engine mufflers

Abstract

A well designed muffler means a compromise between its acoustic performance, backpressure, size and cost criteria. The acoustic performances of engine mufflers, in terms of insertion loss (IL) constitute the major aim of this paper. An experimental investigation of two manufactured mufflers with different inner configurations is realized. Insertion loss investigation is performed in an anechoic room and the experimental setup agrees the ISO 7235:2009 requirements. The analysis in third-octave band of measured noise gives us the sound pressure level on each frequency of interest. Sound attenuation and pressure results are highlighting the influence of mufflers inner configurations on their acoustical behaviour. A FEM analysis completes our study and simulations based on pressure results are performed in order to evaluate the critical displacements correlated to vibration eigenmodes. Our manufactured mufflers realize a good sound attenuation depending of their internal configuration.