Study of multi-chamber micro-perforated muffler with adjustable transmission loss

The noise behavior of the blower used on fuel cell vehicles is measured and analyzed. According to the noise behaviors, the multi-chamber micro-perforated muffler with adjustable transmission loss is proposed for silencing. The adjustment is achieved by the change of the third chamber length. The relation model between the chamber length and the muffler resonant frequency is fitted. In addition, the muffler sample is manufactured for experiment. According to the study, the blower noise contains the wide band noise with frequency range of 500-1000 Hz and the narrow band harmonics with frequency range of 2000-3500 Hz. The experimental results show that the proposed muffler is effective and efficient to attenuate the low-medium frequency wide band noise and the narrow band harmonics simultaneously.