A noise attenuation panel comprises a sound absorbing honeycomb layer disposed between a perforated surface layer on an airflow facing side of the panel and a composite support layer on a second opposing side of said panel. The composite material support layer comprises an electrical heat source.

An acoustic treatment device for an aircraft turbojet engine nacelle forms an annular ring including several sections, each section having a sound absorption structure, an outer skin and two lateral skins attached to the inner air inlet shroud of such a nacelle by fasteners, and the sections being connected to each other by battens.

A heat engine including a liner extended along a first dimension and a second dimension, wherein the liner includes a plurality of cavities formed by a honeycomb structure. Each cavity forms a volume extended from an opening at a fluid contact side of the liner and along a third dimension substantially orthogonal to the first dimension and the second dimension. The opening at the fluid contact side includes a cross sectional area of each respective volume of the plurality of cavities. The plurality of cavities is non-uniform with respect to the cross sectional area at the opening along the first dimension, the second dimension, or both.

Hybrid turbomachine comprising an electric generator, a gas generator equipped with an air inlet and with an exhaust and an acoustic monitoring system comprising a control unit and a plurality of loudspeakers.

At least a first loudspeaker is disposed on the electric generator, and/or at least a second loudspeaker is disposed on the air inlet of the gas generator, and/or at least a third loudspeaker is disposed on the exhaust of the gas generator.

The control unit of the acoustic monitoring system is mounted on the electric generator and is configured to make an AC-DC electrical conversion of the electromotive force of the electric generator into an adjustable DC voltage intended to be distributed to loads or to energy storage means.

An aircraft nacelle including a conduit rigidly connected to an air inlet and a conduit rigidly connected to an engine, a link between the conduit rigidly connected to the air inlet and the conduit rigidly connected to the engine. The link includes a sleeve that receives one end of a first conduit and is rigidly connected to a second conduit, and linking elements that link the sleeve and the first conduit and that are distributed about the entire circumference of the nacelle, each linking element having a threaded stem oriented in a radial direction and being configured to enable tightening from inside the first conduit.

An assembly is provided for an aircraft propulsion system. This assembly includes a first acoustic panel and a second acoustic panel. The first acoustic panel includes a first perforated skin, a first non-perforated skin and a first cellular core arranged between and connected to the first perforated skin and the first non-perforated skin. The first perforated skin is configured with a plurality of first perforations. A first of the first perforations has a first width. A second acoustic panel includes a second perforated skin, a second non-perforated skin and a second cellular core arranged between and connected to the second perforated skin and the second non-perforated skin. The second perforated skin is configured with a plurality of second perforations. A first of the second perforations has a second width that is smaller than the first width.

The present disclosure concerns an acoustic attenuation panel for an aircraft turbojet engine nacelle and a method for manufacturing this panel. The acoustic attenuation panel includes an alveolar central core interposed between an acoustic front skin comprising perforations and a rear skin, the acoustic attenuation panel including a front structure and a rear structure. The front structure includes the acoustic front skin and a first network of alveolar walls, the rear structure including the rear skin and a second network of alveolar walls, the first and second networks of alveolar walls being complementary so as to form, in an assembled position, the alveolar central core, the front structure and the rear structure being positioned opposite to each other and so that the network of alveolar walls of a structure is spaced from the skin of the other structure facing it by a clearance d.

An acoustic liner includes a core including a plurality of cells extending between a first side of the core and a second side of the core opposite the first side of the core. The acoustic liner further includes a back skin including a light-reflecting layer. The light-reflecting layer includes a first side attached to the first side of the core. The acoustic liner further includes a face skin. The face skin includes a first side attached to the second side of the core.

Systems and methods are presented for acoustic dampening in a rotating machine. The rotating machine has a rotatable shaft defining an axis of rotation and a gas flowpath. A system comprises an acoustic panel affixed to an annular casing. The acoustic panel comprises an acoustic treatment member extending between a radially inner skin and radially outer skin. The radially inner skin extends the full axial and circumferential dimensions of the acoustic panel, and the acoustic treatment member overlays the entirety of the radially inner skin. The acoustic panel is positioned so that the radially outer skin abuts the casing, the abutting surfaces being configured to effect relative axial movement between the surfaces while maintaining contact between the surfaces. The acoustic panel is affixed in position to the casing by one or more fasteners passing through the casing and a portion of the radially outer skin.

A general mounting method for ducted fan propulsors is disclosed. This mounting method uses extremely slender stators that connect the duct ring to the propulsor which is mounted in the middle and drives the rotor, fan or propeller. The slender stators take the form of spokes and as such are so slender that the midspan stresses within the spokes are dominated by axial tension loads rather than the shear loads experienced by conventional stators. The spokes may have an aerodynamic shape and damping methods may be used to retard spoke vibrations and transmission of engine vibrations to the duct and force. The duct itself is also stiffened by the spoke arrangement, thereby reducing low frequency vibration modes.