Effect of geometric parameters on the acoustical performance of single inlet single outlet expansion chamber muffler

Muffler is an important component in any machinery where sound is needed to be muffled or attenuated. Mufflers of various geometric configurations are available with main focus on getting maximum transmission loss without having undesirable impact on back pressure. This paper predicts the acoustical performance of a single inlet single outlet expansion chamber muffler. Finite element method is used to predict the transmission loss of the muffler at different geometrical parameters and then these results are compared with the results obtained from the plane wave theory. Guidelines are also suggested for better attenuation by comparing the results obtained by varying the geometry. Finite element pressure plots at some of the critical frequencies are plotted to demonstrate the wave propagation and wave inhibition phenomenon. This study is carried for the frequency range of 50 Hz to 1500 Hz.