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Exhaust Noise Abatement with Porous Sintered Metal Silencer
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1985 by SAE International in United States
Annotation ability available
The exhaust system is often one of the main sources of vehicle noise. A new type of exhaust silencer made of porous sintered aluminum and installed at the end of the exhaust tube considerably reduces this noise, with no rise in back pressure.
The mechanism of noise abatement is analyzed utilizing fluid dynamic analysis techniques. It is concluded that noise reduction results mainly from the fluid dynamic effects arising from the gas permeability of the material. Among these effects are the boundary layer control effect of the inner flow, flattening of the velocity profile, heat dispersion effect, decrease in turbulence of flow, smoothing of exhaust pulsation, contraction of the mixing region, and the resulting large decrease in the volume of the noise source.
In regard to acoustical effect, the sintered metal can be thought of as Helmholtz resonators. The change in the end condition as an acoustic tube also reduces the peak level of acoustic resonance.
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CitationAbe, T., Yoshimori, K., and Azuma, A., "Exhaust Noise Abatement with Porous Sintered Metal Silencer," SAE Technical Paper 850326, 1985, https://doi.org/10.4271/850326.
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