Three-pass perforated tube muffler with perforated bulkheads

Abstract

The one-dimensional analytical approach is developed to predict and analyze the acoustic attenuation performance of three-pass perforated tube muffler with perforated bulkhead(s) and validated by comparing the transmission loss results from one-dimensional analytical approach and finite element method. The one-dimensional analytical approach is then used to investigate the effect of perforated bulkhead(s) on the acoustic attenuation performance of three-pass perforated tube reactive and hybrid mufflers. The results indicated that perforates on the bulkhead may change the resonant frequency of the three-pass perforated tube reactive muffler, and the resonance frequency is shifted to higher frequency with the increase in the porosity of perforation. The sound-absorbing material filling in the middle chamber may improve the acoustic attenuation performance of the mufflers from middle to high frequencies, while the acoustic attenuation performance around the resonance frequencies is lowered somewhat; therefore, a flatter acoustic response may be formed for the hybrid muffler than the reactive muffler.