Abilities of reactive silencers in large ducts

The paper is devoted to silencers formed by dividing the duct with the multimode composition of sound waves into ducts with a single-mode composition along one of cross-section coordinate. The geometry of the silencer ducts fulfilled from stepped partitions allows meeting the acoustic, aerodynamic and dimensional requirements for silencers of devices that move air flows. For the silencer of the most technological layout the parameters of slotted ducts’ expansion chambers were established as well as the possibility to remove dust and moisture from the silencer during operation. For the silencer with reduced aerodynamic resistance the distances between cuts of slotted ducts pushed inside the expansion chambers were revealed. Creating the conditions for single-mode sound propagation along the second cross-section coordinate provides double noise reduction by the silencer. Additional resonator system extends the frequency range of the silencer.