Afterbody for a turbojet engine comprising a nozzle provided with a thrust reverser system that incorporates a crown of noise-reducing chevrons

Patent metadata

Field	Value
Publication number	US-10036349-B2
Application number	US-201414916467-A
Country	US
Kind code	B2
Filing date	Sep 5, 2014
Priority date	Sep 10, 2013
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

An afterbody for a turbojet engine having a central axis, provided with a nozzle comprising two doors facing each other between two lateral beams. The doors pivot around axes defining a pivot direction, between a retracted position, in which a middle portion of the downstream edge of the doors forms the edge of the outlet section of the nozzle combined with the downstream edges of the two lateral beams, and a deployed position, in which the middle portions of the downstream edges of the pivoting doors come together so as to block the channel between the two lateral beams in order to reverse the thrust of the turbojet engine gases. The edge of the outlet section of the nozzle further having a crown of noise-reducing chevrons alternating with indentations and the afterbody.

First claim

The invention claimed is:

1. An afterbody of a turbojet engine having a central axis, the afterbody comprising:
an exhaust nozzle including first and second doors mounted opposite one another between two lateral beams and pivoting about shafts defining a pivot direction, each door of the first and second doors having a downstream edge provided with a middle portion, said first and second doors pivoting between a retracted position, in which said middle portions of the first and second doors form an edge of an output portion of the exhaust nozzle in combination with downstream edges of the two lateral beams, and a deployed position, in which said middle portions of the downstream edges of the first and second doors join together to block a channel between the two lateral beams in order to reverse the thrust of gases from the turbojet engine,
wherein the edge of the output portion of the exhaust nozzle includes a ring comprised of noise-reduction chevrons alternating with indentations, the middle portion of the first door comprising a first portion of the noise-reduction chevrons and a first portion of the indentations, the middle portion of the second door comprising a second portion of the noise-reduction chevrons and a second portion of the indentations, and said downstream edges of the lateral beams each comprising a number of noise-reduction chevrons and a number of indentations,
said ring being arranged such that a portion of each noise-reduction chevron formed on the middle portion of the downstream edge of one door of the first and second doors is opposite a portion of a respective indentation formed in the middle portion of the downstream edge of the other door of the first and second doors in a direction which is perpendicular to said pivoting direction,
said afterbody being arranged such that when the first and second doors are in the deployed position, the portion of each noise-reduction chevron formed on the middle portion of the one door of the first and second doors interlock with the portion of the respective indentation formed in the middle portion of the other door of the first and second doors without any overlapping of the middle portions of the first and second doors with regard to a transverse plane perpendicular to an axial plane of the turbojet engine.

2. The afterbody of a turbojet engine according to claim 1 , wherein the ring of noise-reduction chevrons includes a part of a noise-reduction chevron on the downstream edges of the lateral beams, the portion of noise-reduction chevrons of said middle portion of the downstream edge of the first and second doors and the part of the noise-reduction chevron on the downstream edges of the lateral beams being separated close to an apex of an indentation.

3. The afterbody of a turbojet engine according to claim 2 , wherein a geometry of the part of the noise-reduction chevrons placed on the downstream edges of the two lateral beams differs from portions of the noise-reduction chevrons placed on the middle portion of the downstream edge of the first and second doors so as to improve the acoustic performance of the part of the noise-reduction chevrons placed on the lateral beams by comparison with the portions of the noise-reduction chevrons placed on the first and second doors.

4. The afterbody of a turbojet engine according to claim 1 , wherein the number of noise-reduction chevrons in the ring is odd.

5. The afterbody of a turbojet engine according to claim 1 , wherein the noise-reduction chevrons on the first and second doors are symmetrical with respect to the axial plane of the turbojet engine which is perpendicular to said pivoting direction.

6. The afterbody of a turbojet engine according to claim 1 , wherein the indentations and the noise-reduction chevrons have a substantially triangular shape having rounded apexes on the downstream edges of the first and second doors.

7. The afterbody of a turbojet engine according to claim 1 , wherein a penetration into the channel of the portion of the noise-reduction chevrons placed on the middle portion of the downstream edge of the first and second doors decreases as the distance thereof increases from an axial plane which is perpendicular to said shafts defining the pivoting direction.

8. The afterbody of a turbojet engine according to claim 1 , wherein a distance separating two points connecting the downstream edge of each lateral beam to the middle portion of the downstream edge of the first and second doors is at least equal to two thirds of a maximum gap between the middle portions of the downstream edge of the first and second doors in the plane which is transverse to a central axis which passes through said two points.

9. A mixed-flow turbojet engine comprising an afterbody according to claim 1 .

10. The mixed-flow turbojet engine according to claim 9 , further comprising a lobed mixer inside the exhaust nozzle, the lobed mixer including divergent lobes, wherein the divergent lobes are equal in number to the noise-reduction chevrons and are centered in azimuth on said noise-reduction chevrons.

11. The afterbody of a turbojet engine according to claim 1 , wherein the shafts are installed on said lateral beams and each first and second doors comprise two symmetrical holes with regard to the axial plane of the turbojet engine, said two symmetrical holes being aligned coaxially with two of the shafts.

12. The afterbody of a turbojet engine according to claim 1 , wherein the first and second doors form at least a portion of a wall of the exhaust nozzle.

13. The afterbody of a turbojet engine according to claim 1 , wherein the first portion of the noise-reduction chevrons of the first door interlock with the second portion of the indentations of the second door without physical contact.

14. An afterbody of a turbojet engine having a central axis, said afterbody comprising:
an exhaust nozzle including a first door and a second door mounted opposite one another between two lateral beams and pivoting about shafts defining a pivoting direction, each first and second door having a downstream edge provided with a middle portion, said first and second doors pivoting between a retracted position, in which said middle portions of the first and second doors form an edge of an output portion of the exhaust nozzle in combination with downstream edges of the two lateral beams, and a deployed position, in which said middle portions of the first and second doors join together to block a channel between the two lateral beams in order to reverse the thrust of exhaust gas of the turbojet engine,
wherein the edge of the output portion of the exhaust nozzle includes a ring of noise-reduction chevrons alternating with indentations, the middle portion of the first door comprising a first portion of the noise-reduction chevrons and a first portion of the indentations, the middle portion of the second door comprising a second portion of the noise-reduction chevrons and a second portion of the indentations, and said downstream edges of the two lateral beams each comprising a number of noise-reduction chevrons and a number of indentations,
said ring of noise-reduction chevrons alternating with indentations being arranged such that the first portion of the noise-reduction chevrons being formed on the middle portion of the downstream edge of the first door is opposite the second portion of the indentations formed in the middle portion of the second door in a direction which is perpendicular to said pivoting direction,
said afterbody being arranged such that when the first and second doors are in the deployed position, the first portion of the noise-reduction chevrons

Assignees

• Snecma
• Aircelle Sa

Inventors

• Kernemp Irwin
• Langridge Jonathan
• Pascal Sébastien
• Guillois Denis
• Clere Gérard
• Chapelain Loïc

Classifications

• F02K1/763

  with actuating systems or actuating devices; Arrangement of actuators for thrust reversers · CPC title

• F05D2250/182

  crenellated, notched · CPC title

• F02K1/48 Primary

  Corrugated nozzles · CPC title

• F02K1/62

  by blocking the rearward discharge by means of flaps · CPC title

• F02K1/827

  Sound absorbing structures or liners · CPC title