Turbomachine nozzle cover provided with triangular patterns having a point of inflexion for reducing jet noise

#The present invention relates to the general field of reducing noise from the jet leaving a turbomachine nozzle. It relates more particularly to a cover for the nozzle of a separate-stream type turbomachine, which cover is provided with patterns for reducing noise from the jet.

#Nowadays sound pollution has become a major concern for engine manufacturers who are being challenged more and more concerning the sound nuisance of their turbomachines. The sources of noise in a turbomachine are numerous, but it has been found that the noise from the jet leaving the nozzle is the predominant noise during aircraft takeoff. Since certification authorities are becoming more and more difficult to satisfy in terms of sound emission from turbomachines, engine manufacturers have been required to make efforts to reduce noise from their turbomachines, and in particular noise from the jet leaving the nozzle.

#Typically, a separate-stream nozzle of a turbomachine comprises a primary cover coaxial about the longitudinal axis of the turbomachine, a secondary cover disposed coaxially around the primary cover so as to define a first annular channel along which an outer stream (or cool stream) flows, and a central body disposed coaxially inside the primary cover so as to define a second annular channel along which an inner stream (or hot stream) flows, the primary cover extending beyond the secondary cover.

#Other characteristics and advantages of the present invention appear from the description given below with reference to the accompanying drawings that show an embodiment having no limiting character. In the figures:

#FIG. 1 is a diagrammatic perspective view of a turbomachine nozzle fitted with a cover constituting an embodiment of the invention;

#FIG. 2 is a an enlarged view of a jet noise reduction pattern of the FIG. 1 cover;

#FIG. 1 is a highly diagrammatic perspective view of a separate-stream turbomachine nozzle 10.

#The nozzle 10 is circularly symmetrical about its longitudinal axis X-X and is typically constituted by a primary cover 14, a secondary cover 16, and a central body 18, all centered on the longitudinal axis X-X of the nozzle.

#The primary cover 14 is substantially cylindrical or tapering in shape, extending along the longitudinal axis X-X of the nozzle. The central body 18 is disposed coaxially inside the primary cover 14 and is terminated by a portion that is substantially conical.