EFFECT OF PERFORATION ON ACOUSTIC ATTENUATION CHARACTERISTICS OF TRIPLE CHAMBER MUFFLER

The mufflers are widely used to attenuate the intake and exhaust noise of internal combustion engines. In order to improve the acoustic attenuation in the specific frequency range and flow characteristics, the internal tubes and bulkheads of mufflers are perforated usually. In the present study, the effects of perforations on the acoustic attenuation characteristics of triple chamber mufflers are investigated numerically by using finite element method (FEM). The transmission loss of a typical three-pass perforated tube muffler is predicted first and compared with the measurements. The good agreement illustrated the applicability and accuracy of the FEM for the prediction of acoustic attenuation performance of multiple chamber mufflers with perforated components. Then the FEM is employed to predict the acoustic attenuation characteristics of the triple chamber mufflers and to investigate the effects of perforated tube(s) and bulkhead(s) on the resonance frequency and transmission loss of the mufflers.