Calculation and Analysis of Acoustic Characteristics of Straight-Through Perforated Pipe Muffler Based on Multilayer Sound Absorbing Material

Using the multi-physical field simulation software COMSOL,the acoustic characteristics of the multilayer sound absorbing material straight-through perforated pipe muffler are studied by the finite element method.The results show that the finite element calculation of the multilayer sound absorbing material straight-through the perforated pipe muffler agrees well with the experimental measurement results.The reliability of the finite element method for studying the acoustic performance of the straight-through perforated pipe muffler with multilayer sound absorbing materials is shown.Furthermore,the influence of some structural parameters of porous sound absorbing material and micro-perforated plate on the acoustic performance of the multilayer sound absorbing material straight-through perforated pipe muffler is analyzed.The muffler based on multilayer sound absorbing material is different from the traditional muffler.After applying the multilayer sound absorbing material to the straight-through perforated pipe muffler,the transmission loss value greatly increases,which provides new ideas and directions for future research on the muffler.

Theoretical Calculation and Analysis of Muffler Based on Multilayer Sound Absorbing Material

The multilayer impedance composite sound absorption structure of the new muffler is proposed by combining the microporous plate structure with the resonant sound absorption structure of the porous material.Firstly,the acoustic impedance and acoustic absorption coefficient of the new muffler structure are calculated by acoustic electric analogy method,and then the noise attenuation is calculated.When the new muffler structure parameters change,the relationship among the noise frequency,the sound absorption coefficient and the noise attenuation is calculated by using MATLAB.Finally,the calculated results are compared with the experimental data to verify the correctness of the theoretical calculation.The variation of resonance peak,resonance frequency and attenuation band width of each structural parameter is analyzed by the relation curve.The conclusion shows that it is feasible to use multilayer sound absorbing materials as the body structure of the new muffler.And the influence relationship between the change of various parameters of the sound absorption structure with the sound absorption coefficient and noise attenuation is obtained.