Resumo

RASTELLI, VICTORIA et al. Automatic design of reactive mufflers: Performance analysis part II. Rev. Fac. Ing. UCV [online]. 2008, vol.23, n.3, pp.75-81. ISSN 0798-4065.

Noise pollution may cause important physiological and/or psychological harm to human beings, as mentioned in part one of this work. As such, a versatile and user friendly program, named PADSA, was developed and used to analyze a single chamber muffler performance. In this part, PADSA is used to complete the analysis of reactive mufflers considering double chamber mufflers with both external and internal connection tubes. From these analyses it is observed that, just as in the case of single chamber mufflers, an increase in the relationship of area causes a rise in transmission losses, with no change in the frequency of occurrence of the maximum and minimum values; that the selection of the muffler lengths can be optimized in order to achieve maximum loss with minimum longitude; and a temperature increase produces a phase modification in the transmission loss curve, which affects the muffler performance. Additionally, it was determined that there are critical relationships between the tube connector length and the lengths of the chambers that can produce a significant reduction in transmission losses and that for mufflers with an internal connector, the optimal length is highly dependent on the spectrum to be attenuated. Finally, it is important to mention that mufflers with an internal connector are more effective than those with an external one.

Palavras-chave : Mufflers; Reactive; Automatic design; Performance; Noise contamination.