THIS COMMUNICATION IS CANCELLED. Porous air inlet ducts: acoustic power radiated along the duct compared to nozzle noise

Matthieu Baudry

The air intake systems of internal combustion engines are comprised of ducts and air boxes (e.g. air cleaner). The lengths of the ducts induce resonances that may be excited by the air pulsations generated by the air intake valves of the engine. In cases of loud air intake noise, when acoustic devices cannot be used to counteract resonances, a common solution is to use porous ducts: non woven ducts, or ducts with slits (considered as local porosities). Such a solution has an important drawbacks: (1) Dust can fill the pores, leading to loss of effectiveness; (2) The acoustic power radiated along the duct increases. The last issue is addressed here with measurements: the acoustic power radiated along the duct is compared to the acoustic power radiated by the nozzle, in different conditions (with or without porosity, homogeneous or discrete porosity, various airflow velocities). The aim is to validate that porosities give a good balance between the decrease of nozzle noise resonances and the increase of radiated noise along the duct.

Mots clés: duct resonance; porous medium; radiated power; IC engine

Domaines: Acoustique [physics.class-ph]

Matthieu Baudry. THIS COMMUNICATION IS CANCELLED. Porous air inlet ducts: acoustic power radiated along the duct compared to nozzle noise. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810993⟩