Fastening of an exhaust cone in a turbomachine nozzle

Abstract

An assembly for a turbomachine nozzle having a longitudinal axis (X) includes an exhaust cone with an annular outer wall for guiding a primary air flow and an annular chamber placed radially inside said annular outer wall. The annular chamber includes an annular inner wall placed radially inside the annular outer wall of the exhaust cone. An exhaust case is placed upstream of the ejection cone. A connecting member is interposed longitudinally between the exhaust case and the exhaust cone and fastened to the exhaust case and to the annular inner wall. The assembly further includes elastic means configured to deform radially and prestressed radially between the annular outer wall and the connecting member.

Claims

1. An assembly for a turbomachine with a longitudinal axis (X) comprising: an exhaust cone comprising an outer annular wall for the flow of a primary air flow and an annular box arranged radially inside said outer annular wall, the annular box comprising an inner annular wall arranged radially inside the outer annular wall of the exhaust cone, an exhaust case arranged upstream of the exhaust cone, and a connecting member interposed longitudinally between the exhaust case and the exhaust cone, the connecting member being fastened to the exhaust case and to the inner annular wall, said assembly further comprising at least one elastic means radially deformable and radially prestressed between the outer annular wall and the connecting member, wherein the connecting member comprises an annular flange connected to a corresponding flange of the exhaust case and a plurality of fastening lugs distributed circumferentially around the longitudinal axis and connected to the inner annular wall.

2. The assembly according to claim 1, further comprising means for limiting a radial displacement of the outer annular wall, said radial displacement limiting means being interposed between the outer annular wall and the connecting member, wherein said radial displacement limiting means form a radial stop of the outer annular wall against the connecting member.

3. The assembly according to claim 1, wherein the elastic means are fastened to the outer annular wall and are in radial contact against the connecting member or fastened to the connecting member and are in radial contact against the outer annular wall.

4. The assembly according to claim 2, wherein the radial displacement limiting means are fastened to the outer annular wall and are in radial contact against the connecting member or fastened to the connecting member and are in radial contact against the outer annular wall.

5. The assembly according to claim 2, wherein at least one elastic means is superimposed with a radial displacement limiting means.

6. The assembly according to claim 2, wherein at least one elastic means is circumferentially spaced apart from one of the radial displacement limiting means.

7. The assembly according to claim 1, wherein at least one elastic means is a leaf spring, the leaf springs being distributed circumferentially around the longitudinal axis.

8. The assembly according to claim 7, wherein at least one of said leaf springs comprises a first flexible leaf extending in a first direction of the circumferential direction around the longitudinal axis and a second flexible leaf extending in a second direction of the circumferential direction around the longitudinal axis (X) opposite to the first direction.

9. The assembly according to claim 7, wherein at least one of said leaf springs comprises one single leaf extending radially along the longitudinal axis (X).

10. The assembly according to claim 9, wherein at least one of said leaf springs forms a radial displacement limiting means.

11. The assembly according to claim 1, further comprising a first annular seal surrounding the junction between the connecting member and the inner annular wall, said first annular seal being configured to limit the circulation of the primary air flow towards a cavity of the exhaust cone.

12. The assembly according to claim 1, further comprising a second annular seal connected to the connecting member and extending radially towards the outer annular wall, said second annular seal being configured to prevent the primary air flow from passing through the outer annular wall.

13. The assembly according to claim 1, wherein the elastic means are formed by an annular seal fastened to the connecting member and comprising a radially deformable part bearing against the outer annular wall.

14. The assembly according to claim 2, wherein each displacement limiting means is formed by a buffer, wherein the buffers being are distributed circumferentially around the longitudinal axis (X) and are held at a predetermined distance with the connecting member in the radial direction.

15. The assembly according to claim 1, wherein a downstream portion of the outer annular wall is fastened to a downstream portion of the inner annular wall.

16. A turbomachine nozzle comprising an assembly according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1, already described, represents a schematic sectional profile of a turbomachine for an aircraft.

(2) FIG. 2 represents a schematic sectional view of a portion of an exhaust cone equipped with a first example of elastic means.

(3) FIGS. 3a and 3b represent a schematic perspective view of the upstream portion of an exhaust cone equipped with a second example of elastic means.

(4) FIG. 4 represents a sectional view of the upstream portion of the exhaust cone of FIG. 3.

(5) FIG. 5 represents a sectional view of the upstream portion of an exhaust cone equipped with an example of a primary air flow recirculation seal.

(6) FIGS. 6a and 6b represent a schematic perspective view of the upstream portion of an exhaust cone equipped with a variant of the second example of elastic means.

(7) FIGS. 7a and 7b represent a schematic perspective view of the upstream portion of an exhaust cone equipped with a variant of the second example of elastic means.

(8) FIG. 8a represents a schematic perspective view of the upstream portion of an exhaust cone equipped with a third example of elastic means and FIG. 8b represents a sectional view of the exhaust cone of FIG. 8a.

(9) FIG. 9 represents a schematic sectional view of the upstream portion of an exhaust cone equipped with a variant of the third example of elastic means.

(10) FIG. 10 represents a schematic perspective view of an upstream portion of an exhaust cone equipped with a fourth example of elastic means.

DETAILED DESCRIPTION OF THE INVENTION

(11) Referring to FIG. 2, the nozzle exhaust cone 100 comprises an outer annular wall 102 for the flow of a primary air flow connected to a conical downstream portion 104 of the exhaust cone, for example by bolting.

(12) For example, the outer annular wall 102 is metallic or made of a composite with a ceramic matrix and the conical downstream portion 104 is made of a composite material with a ceramic or metallic matrix.

(13) An annular acoustic box 106 is arranged in the outer annular wall 102. The annular acoustic box 106 comprises an inner annular wall 108 arranged radially inside the outer annular wall 102 and a plurality of partitions not represented in FIG. 2 and arranged radially between the outer annular wall 102 and the inner annular wall 108. Other annular boxes could be arranged herein without these consisting of annular boxes ensuring an acoustic function, i.e. reducing the air outlet noises of the turbomachine.

(14) For example, the inner annular wall 108 and/or the acoustic partitions may be made of a metal or composite material with a ceramic matrix.

(15) The exhaust cone 100 is connected to a flange 110 of an exhaust case 109 of the nozzle carrying the exhaust cone 100. In particular, the inner annular wall 108 is connected to the flange 110 of the exhaust case 109 by a connecting member 112.

(16) The connecting member 112 comprises an annular flange 114 coupled to the flange 110 of the exhaust case 109 and a plurality of fastening lugs 116 distributed circumferentially around a longitudinal axis X. Each fastening lug 116 is fastened to an upstream portion of the inner annular wall 108. The fastening lugs 116 may be flexible or rigid. The connecting member 112 may be metallic. The fastening lugs 116 may be connected to the inner annular wall 108 by bolting.

(17) The downstream portion of the outer annular wall 102 may be connected to the downstream portion of the inner annular wall 108 as illustrated in FIG. 2. On the other hand, the upstream portion of the outer annular wall 102 is free to move relative to the inner annular wall 108. This arrangement enables deformations of the upstream portion of the outer annular wall 102 due to the thermomechanical stresses related to the operating temperature of the exhaust cone 100 and the difference in the materials in the exhaust cone 100.

(18) In addition, a plurality of elastic means 118 are arranged radially between the outer annular wall 102 and the connecting member 112, so as to be radially prestressed by the outer annular wall 102 against the inner annular wall 108 or the connecting member 112.

(19) The radially deformable elastic means 118 are distributed circumferentially around the longitudinal axis X. For example, each elastic means 118 may be formed by a radially deformable leaf extending axially from the annular wall 102 towards the inner annular wall 108 and radially outwards.

(20) The elastic means 118 allow distributing the forces between the upstream and downstream junction of the outer annular wall 102 and therefore reducing the thickness of the outer annular wall 102 as well as its mass. In addition, the elastic means 118 improve the vibratory behavior of the outer annular wall 102.

(21) The outer annular wall 102 extends so as to form a continuity of a shroud 111 of the exhaust case 109.

(22) In the example of FIGS. 3a, 3b and 4, the exhaust cone 100 of FIG. 2 is provided with elastic means 200, on the one hand, fastened to the outer annular wall 102, and on the other hand bearing against the annular flange 114 of the connecting member 112. The elastic means 200 are formed by leaf springs, each comprising a first leaf 2021 extending radially inwards from the outer annular wall 102 and in a first direction of a circumferential direction around the longitudinal axis X. Each leaf spring comprises a second leaf 2022 extending radially inwards from the outer annular wall 102 and in a second direction of the circumferential direction opposite to the first direction. The first and second leaves 202 are flexible and can deform radially.

(23) Radial displacement limiting means 204 in the form of buffers 204 are arranged radially between the outer annular wall 102 and the connecting member 112. A predetermined distance 205 is kept radially between the buffers 202 and the connecting member 112 so as to form a stop if the outer annular wall 102 undergoes considerable radial deformations, i.e. a radial deformation greater than the predetermined distance 205. Each buffer 204 is fastened to a leaf spring 200, in particular on a central portion of the leaf spring 200 between the first and second leaves 202. The buffers 204 may be rigid or flexible.

(24) The buffers 204 may be assembled to the leaf springs 200 or formed integrally with the leaf springs 200.

(25) The exhaust cone 100 is further provided with a first seal 206 with an annular shape around the longitudinal axis X and surrounding on the one hand the axial space between the inner annular wall 108 and the circumferential spaces between the fastening lugs 116. Thus, the primary air flow cannot infiltrate inside the exhaust cone 100 which might reduce the performances of the nozzle carrying the exhaust cone 100.

(26) The first seal 206 is made of a metallic material, for example tungsten or Inconel, to withstand the high temperatures of the primary air.

(27) The first seal 206 may be formed by a plurality of angular sectors connected together and partially overlapping.

(28) The first seal 206 comprises a downstream end 208 arranged so as to bear against the inner annular wall 108 and an upstream end 210 arranged so as to bear against the annular flange 114 of the connecting member 112. The upstream end 210 of the first seal 206 may be fastened directly on the annular flange 114 of the connecting member 112.

(29) The leaf springs 200 are in contact with the first seal 206.

(30) FIG. 5 represents an arrangement similar to the arrangement of the exhaust cone 100 of FIGS. 3 and 4. Conversely, the exhaust cone 100 of FIG. 5 is provided with a second seal 212 arranged so as to radially cover the space between the annular flange 114 of the connecting member 112 and the outer annular wall 102.

(31) The outer annular wall 102 bears against the second seal 212. The second seal 212 may be fastened to the annular flange 114 of the connecting member 112 or may be arranged in contact against the annular flange 114 of the connecting member 112. The second annular seal 212 is metallic and is formed by a plurality of angular sectors distributed circumferentially around the longitudinal axis and connected together so as to form the second annular seal 212.

(32) In the variant of FIGS. 6a and 6b, the elastic means 200 are decoupled from the radial displacement limiting means 204. Each elastic means 200 is circumferentially spaced apart from a radial displacement limiting means 204.

(33) The elastic means 200 and the radial displacement limiting means 204 are fastened directly to the outer annular wall 102 and are arranged on the same circumferential row.

(34) In the variant of FIGS. 7a and 7b, the elastic means 200 and the radial displacement limiting means 204 are fastened to the inner annular wall 108, in particular to the first seal 206. The elastic means 200 and the radial displacement limiting means 204 are superimposed and arranged circumferentially at the same location.

(35) Referring to FIGS. 8a and 8b, the exhaust cone 100 is equipped with one single annular elastic means 300 arranged on the one hand in contact against the inner annular wall 108 and on the other hand in contact with the outer annular wall 102.

(36) The annular elastic means 300 has a downstream end bearing against the inner annular wall 108 and an upstream end 306 bearing against the connecting member 112. The upstream end 306 may also be fastened to the connecting member 112. The annular elastic means 300 comprises a protuberance 304 extending radially outward. The outer annular wall 102 bears against the protuberance 304.

(37) The annular elastic means 300 may be metallic and formed by a plurality of angular sectors connected together. In the variant of FIG. 9, a second annular seal 306 is arranged around the annular elastic means 300. The second seal 306 has an upstream end 308 extending radially outward and comes against the outer annular wall 102. The second seal 306 has an upstream end 310 bearing against the flange 114 of the connecting member 112.

(38) The second seal 306 allows preventing the primary air flow from infiltrating inside the inner annular wall 108.

(39) Referring to FIG. 10, the exhaust cone is provided with a plurality of elastic means 400 having a radially inner end 402 connected to the annular flange 114 of the connecting member 112. The elastic means 400 further have a leaf 404 extending longitudinally and is arranged radially at a distance from the radially inner end 402.

(40) The elastic means 400 further form radial displacement limiting means through the radially outer end 406. This radially outer end 406 has a rim extending radially inward.

(41) The exhaust cone may further comprise elastic means 400, radial displacement limiting means such as radial displacement limiting means 204.