This silencer is used in order to reduce the emitted noise of an exhaust system. The geometry is made of several resonating chambers and contains a core of absorbing material.

The objective of this study was to compare the acoustic behavior of different silencer configurations.

Considering that the flow velocity through the device is quite uniform and that temperature gradients are negligible, there is no need to perform the CFD calculation of the device. Only an acoustic calculation is required. To this end, the dedicated TL (Transmission Loss) analysis module from FINE™/Acoustics was used.

As the frequency range is quite large (from 25Hz to 4kHz), several meshes were generated using HEXPRESS™/Hybrid software from NUMECA. The finest mesh is only used for the highest frequencies, hence reducing the total computational cost.

The post-processing included the evolution of the noise attenuation in dB as a function of the frequency, for each silencer configuration.

The pictures describe the geometry, the intermediate acoustic mesh and the acoustic pressure field, showing the strong noise attenuation in the absorber.




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