Device for reducing the noise emitted by the jet of an aircraft propulsion engine

Patent metadata

Field	Value
Publication number	US-9422887-B2
Application number	US-201113696821-A
Country	US
Kind code	B2
Filing date	May 11, 2011
Priority date	May 12, 2010
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

A gas exhaust nozzle for aircraft propulsion includes at least a downstream part with a trailing edge of chevron type formed of chevrons distributed along the periphery of the nozzle. Each chevron extends downstream between an upstream transverse plane and a downstream transverse plane with free edges oriented in two converging downstream directions and defining the trailing edge. The chevrons generate vortices at the boundary of the jet emitted by the nozzle. The gas exhaust nozzle includes a device to inject auxiliary gas jets upstream of the free edges of the chevrons in the main jet through orifices placed upstream of the upstream plane in such a way as to discharge upstream of the upstream plane of the chevrons to generate the vortices upstream of the free edges of the chevrons.

First claim

The invention claimed is:

1. A gas exhaust nozzle for aircraft propulsion, comprising:
at least a downstream part with a trailing edge of chevron type, formed of chevrons distributed along a periphery of the nozzle, the nozzle having a longitudinal axis, each chevron extending downstream and being entirely delimited between an upstream transverse plane and a downstream transverse plane, the upstream transverse plane being perpendicular to the longitudinal axis, said trailing edge defined by a plurality of free edges and each chevron including a first free edge and a second free edge, each chevron being rigidly connected to the nozzle via a fixed edge situated. in the upstream transverse plane, the first free edge and the second free edge of each chevron converging towards each other while extending from the fixed edge to the downstream transverse plane, each chevron including a first plane defining an intersection of the first free edge with the fixed edge, and a second plane defining an intersection of the second free edge with the fixed edge, the first plane and the second plane being perpendicular to the upstream transverse plane, the chevrons generating vortices at a boundary of a main jet emitted by the nozzle; and
an injection device which injects auxiliary gas jets upstream of said free edges of the chevrons in the main jet through orifices separate from the chevrons, the orifices being placed adjacent to and upstream of said upstream plane in such a way as to discharge upstream of said upstream plane of th, chevrons to generate said vortices upstream of the free edges of the chevrons,
wherein, for each respective chevron, one or two orifices are disposed circumferentially between the first plane and the second plane of the respective chevron.

2. The nozzle as claimed in claim 1 , wherein the chevrons have an axial plane of symmetry, the orifices of the injection device being disposed in such a way as to inject the auxiliary gas jets on either side of said plane of symmetry.

3. The nozzle as claimed in claim 1 , wherein the orifices of the injection device are disposed in such a way as to inject the auxiliary jets in a direction of an axis of the nozzle at an angle between 10° and 50° to said axis of the nozzle.

4. The nozzle as claimed in claim 1 , wherein the chevrons are of substantially triangular or trapezoidal shape.

5. A multiflow turbojet, comprising:
at least one exhaust nozzle according to claim 1 .

6. The nozzle as claimed in claim 1 , wherein the nozzle is a secondary flow nozzle defining an annular space through which a secondary flow is ejected.

Assignees

• Bodard Guillaume
• Vuillemin Alexandre Alfred Gaston
• Snecma

Inventors

• Bodard Guillaume
• Vuillemin Alexandre Alfred Gaston

Classifications

• F02K1/46

  Nozzles having means for adding air to the jet or for augmenting the mixing region between the jet and the ambient air, e.g. for silencing (F02K1/28, F02K1/36, F02K1/38 take precedence) · CPC title

• F02K1/34 Primary

  for attenuating noise · CPC title

• F05D2250/11

  triangular · CPC title

• F05D2240/40

  Use of a multiplicity of similar components · CPC title

• F05D2250/13

  trapezoidal · CPC title