An acoustic panel comprises a core layer of honeycomb whose opposite sides are covered by face sheets each comprising a perforated metal plate and a sheet of metal cloth such as woven wire or metal felt. The perforated metal plates are bonded to the core and the metal cloth sheets form the outer surfaces of the panel. Each metal cloth sheet has an acoustic resistance of 5 to 300 Rayls. The perforated metal plates have an open area of about 20 to 40 percent in preferred embodiments. Noise in a nozzle is suppressed by disposing a plurality of the acoustic panels in the nozzle duct with the panels oriented radially and spaced apart about a circumference of the duct.
Acoustic sandwich panel with no septum and apparatus and method for suppressing noise in a turbojet nozzle
Akustische Sandwichplatte ohne Septum und Vorrichtung und Verfahren zur Rauschunterdrückung in einer Strahltriebdüse
Panneau sandwich acoustique sans septum et appareil et procédé pour supprimer les bruits dans une tuyère de turboréacteur
2018-11-28
Patent
Electronic Resource
English
IPC: | B64D Ausrüstung für Flugzeuge , EQUIPMENT FOR FITTING IN OR TO AIRCRAFT / G10K Tonerzeugungsvorrichtungen , SOUND-PRODUCING DEVICES / B32B LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM , Schichtkörper, d.h. aus Ebenen oder gewölbten Schichten, z.B. mit zell- oder wabenförmiger Form, aufgebaute Erzeugnisse / F02K JET-PROPULSION PLANTS , Strahltriebwerke |