Intermediate casing hub for an aircraft turbojet engine including a composite outlet pipe

Abstract

The invention relates to an intermediate casing hub of an aircraft turbojet engine, which includes: an outer shroud (14) intended for defining a secondary flow space of a stream of secondary gas on the inside and an inter-flow area on the outside, the outer shroud (14) being provided with a secondary opening (29), and a bleed valve comprising an outlet pipe (30) made of composite material, located in the inter-flow area, wherein the outlet pipe (30) is attached to the outer shroud (14) at the secondary opening (29), at least one gasket (33) for sealing against air and fire being arranged between the outlet pipe (30) and the outer shroud (14), and the outlet pipe (30) made of composite material includes a draped composite wall (30a, 30b), made up of a plurality of folds impregnated with resin.

Claims

1. Hub of intermediate casing for aircraft turbojet engine, comprising: an inner annular shroud delimiting an exterior of a core engine flow space of a core engine gas flow in the turbojet engine, and an interior of an upstream part of at least one inter-flow area, the inner annular shroud being provided with at least one primary air passage orifice, an outer annular shroud that will firstly delimit an interior of a fan flow space of a fan gas flow in the turbojet engine, and secondly delimit an exterior of said at least one inter-flow area, the outer annular shroud being provided with at least one secondary air passage orifice, at least one variable bleed valve, comprising at least one mobile gate capable of drawing off air circulating in the core engine flow space through said at least one primary orifice and sending air thus drawn off to said at least one inter-flow area towards at least one corresponding discharge inlet orifice of at least one outlet pipe of the hub of the intermediate case made of a composite material and shaped to allow an air passage from said at least one discharge inlet orifice to said at least one secondary orifice to send air drawn off through said at last one variable bleed valve into the fan flow space, wherein said at least one outlet pipe is fixed to the outer annular shroud at said at least one secondary orifice, at least one gasket for sealing against air and fire being installed between said at least one outlet pipe and the outer annular shroud and wherein said at least one outlet pipe made of a composite material comprises a draped composite wall composed of a plurality of plies impregnated with resin.

2. Intermediate casing hub according to claim 1, comprising the following: a downstream cross-plate connecting the inner annular shroud and the outer annular shroud, delimiting at least one intermediate space on an upstream side and said at least one inter-flow area on a downstream side, the downstream cross-plate comprising said at least one discharge inlet orifice, wherein the air is drawn up from said at least one primary orifice, through said at least one mobile gate to said at least one intermediate space towards said at least one discharge inlet orifice, wherein said at least one variable bleed valve comprises said at least one outlet pipe, located in said at least one inter-flow area and connecting said at least one discharge inlet orifice and said at least one secondary orifice, and wherein the air drawn off circulating in said at least one intermediate space is sent to the fan flow space.

3. Intermediate casing hub according to claim 1, wherein said at least one gasket for sealing against air and fire is at least partly made from silicone.

4. Intermediate casing hub according to claim 1, wherein the outer annular shroud comprises an annular boss and wherein said at least one outlet pipe comprises an annular joggle, wherein an attachment of said at least one outlet pipe to the outer annular shroud is made through the annular boss and the annular joggle, by screwing through the annular boss and the annular joggle.

5. Intermediate casing hub according to claim 4, wherein an assembly composed of the annular boss and the annular joggle extends entirely around said at least one gasket for sealing against air and fire, forming a separation between said at least one gasket and said at least one inter-flow area.

6. Intermediate casing hub according to claim 1, wherein said at least one outlet pipe comprises a partial annular joggle extending along at least two opposite edges of said at least one outlet pipe, wherein an attachment of said at least one outlet pipe to the outer annular shroud is made through the partial annular joggle, by screwing through the partial annular joggle to raise said composite wall, wherein said at least one gasket is housed between said composite wall and the outer annular shroud.

7. Intermediate casing hub according to claim 6, wherein the outer annular shroud does not have an annular boss.

8. Intermediate casing hub according to claim 1, further comprising a control gate at said at least one secondary orifice, wherein said at least one gasket for sealing against air and fire is placed all around the control gate, and the control gate is fixed to at least one outlet pipe.

9. Intermediate casing hub according to claim 8, wherein said at least one gasket for sealing against air and fire is located between the control gate and an assembly formed by an annular boss and an annular joggle.

10. Intermediate casing hub according to claim 1, wherein said at least one outlet pipe comprises a composite wall with thickness equal to at least 1.5 mm.

11. Intermediate casing hub according to claim 1, wherein the composite wall of said at least one outlet pipe comprises at least 3 impregnated plies.

12. Intermediate casing for aircraft turbojet engine comprising a hub according to claim 1.

13. Aircraft turbojet engine, comprising an intermediate casing according to claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood after reading the following detailed description of a non-limitative example embodiment of it, and after studying the diagrammatic and partial figures in the appended drawing, on which:

(2) FIG. 1 shows an axial section of an example of an intermediate casing hub for an aircraft turbojet engine,

(3) FIG. 2 is a partial diagrammatic axial section illustrating the principle of attachment of an outlet pipe to the outer shroud of an intermediate casing hub of an aircraft turbojet engine according to the invention, in other words manufacturing of the interface between the outlet pipe and the outer shroud of the hub,

(4) FIGS. 3 and 4 are partial diagrammatic axial sections illustrating a manufacturing principle of the upstream wall and the downstream wall respectively of the outlet pipe illustrated in FIG. 2, and

(5) FIG. 5 is a partial perspective view illustrating an example variant embodiment of the outlet pipe of the intermediate casing hub of the aircraft turbojet engine according to the invention in FIGS. 2, 3 and 4.

(6) In all these figures, identical references may denote identical or similar elements.

(7) Moreover, the different parts shown on the figures are not necessarily all at the same scale, to make the figures more easily understandable.

DETAILED PRESENTATION OF A PARTICULAR EMBODIMENT

(8) Note that throughout this description, the terms upstream and downstream should be understood with reference to a principal direction of normal gas flow (from upstream to downstream) for a turbojet engine 12. Furthermore, the radial axis of symmetry of the turbojet engine 12 is called the axis T of the turbojet engine 12. The axial direction of the turbojet engine 12 corresponds to the axis of rotation of the turbojet engine 12, that is the direction of the axis T of the turbojet engine 12. A radial direction of the turbojet engine 12 is a direction perpendicular to the axis T of the turbojet engine 12. Furthermore, unless mentioned otherwise, the adjectives and adverbs axial, radial, axially and radially are used with reference to the above-mentioned axial and radial directions. Furthermore, unless mentioned otherwise, the terms inner (or internal) and outer (external) are used with reference to a radial direction such that the inner part of an element is closer to the axis T of the turbojet engine 12 than the outer part of the same element.

(9) FIG. 1 has already been described in the part describing the state of prior art and the technical context of the invention.

(10) FIG. 2 shows a partial diagrammatic axial section illustrating a principle of attachment of an outlet pipe 30 to the outer shroud 14 of a hub 10 of an intermediate casing 11 of an aircraft turbojet engine 12 according to one example embodiment of the invention, in other words manufacturing of the interface between the outlet pipe 30 and the outer shroud 14 of the hub 10.

(11) Furthermore, FIGS. 3 and 4 are partial diagrammatic axial sections illustrating a manufacturing principle of the upstream composite wall 30b and the downstream composite wall 30a respectively of the outlet pipe 30.

(12) Furthermore, FIG. 5 is a partial perspective view illustrating a variant embodiment of the outlet pipe 30 in FIGS. 2, 3 and 4.

(13) The hub 10 of the intermediate casing 11 according to the invention, associated with FIGS. 2, 3 and 4 described below, can in particular be of the same type as that described above with reference to FIG. 1. Also, for information about the parts not shown on FIGS. 2, 3 and 4 the above description of FIG. 1 should be referred to.

(14) As thus described above, the discharge conduit 30 is located in the inter-flow area ZC and connects the discharge inlet orifice 31 and the secondary orifice 29.

(15) The outlet pipe 30 can then draw off, through the discharge inlet orifice 31, air circulating in the intermediate space 19 and carry the air thus drawn off to the fan flow space 27.

(16) According to the invention, the outlet pipe 30 is fixed to the outer annular shroud 14 at the secondary orifice 29. Furthermore, a gasket 33 gasket for sealing against air and fire is located between the outlet pipe 30 and the outer annular shroud 14.

(17) More precisely, as can be seen on FIG. 2, the outer shell 14 comprises an annular boss 37 and the outlet pipe 30 comprises an annular joggle 36. The attachment of the outlet pipe 30 to the outer shell 14 is then made by screwing 34 through the annular boss 37 and the annular joggle 36.

(18) Furthermore, advantageously, the assembly composed of the annular boss 37 and the annular joggle 36 extends all around the gasket 33, forming a separation between the gasket 33 and the inter-flow area ZC.

(19) Furthermore, there is a control gate 32 located at the secondary orifice 29. The gasket 33 is then placed all around the control gate 32, that is fixed to the outlet pipe 30 by screwing 35. Thus, the gasket 33 is located between the control gate 32 and the assembly formed by the annular boss 37 and the annular joggle 36.

(20) For example, the gasket 33 can be made at least partly from silicone. In particular, it may include a superposition of different plies of fabrics, particularly glass fibre and/or ceramic.

(21) Furthermore, the discharge pipe 30 is made of a composite material. It comprises an upstream composite wall 30b and a downstream composite wall 30a. According to the invention, the upstream wall 30b and the downstream wall 30a are draped, in other words they are obtained by laying up a plurality of plies impregnated with resin, these plies including particularly biaxial or triaxial carbon braids, and the resin being of the bismaleimide type.

(22) The thickness of the outlet pipe 30 and the number of impregnated plies in the outlet pipe 30 can be chosen as a function of the composite materials and the architecture of the outlet pipe 30.

(23) As can be seen on FIG. 3, the downstream composite wall 30a of the outlet pipe 30 comprises three successive portions a1, a2 and a3 in particular.

(24) The first portion a1 comprises for example two large diameter biaxial carbon braids T2, with a thickness of about 0.55 mm, and for example at least six, or even eight, flat carbon triaxial braids T3 with a thickness of about 0.25 mm. Consequently, the thickness E1 of the first portion a1 is at least about 2.6 mm, or even at least about 3.1 mm.

(25) Furthermore, the second portion a2 comprises for example two large diameter biaxial carbon braids T2, with a thickness of about 0.55 mm, and for example two small diameter carbon biaxial braids T1 with a thickness of about 0.55 mm. Consequently, the thickness E2 of the second portion a2 is about 2.7 mm.

(26) Furthermore, the third portion a3 comprises for example two large diameter biaxial carbon braids T2, two small diameter biaxial carbon braids T1 with a thickness of about 0.55 mm. Consequently, the thickness E3 of the third portion a3 is about 2.2 mm.

(27) Moreover, as can be seen on FIG. 4, the upstream composite wall 30b of the outlet pipe 30 also comprises three successive portions b1, b2 and b3 in particular.

(28) The first portion b1 comprises for example two large diameter biaxial carbon braids T2, with a thickness of about 0.55 mm, and for example at least six, or even eight, flat carbon triaxial braids T3 with a thickness of about 0.25 mm. Consequently, the thickness E4 of the first portion b1 is at least about 2.6 mm, or even at least about 3.1 mm, or even at least about 3.8 mm.

(29) Furthermore, the second portion b2 comprises for example two large diameter biaxial carbon braids T2, with a thickness of about 0.55 mm, and for example two small diameter carbon biaxial braids T1 with a thickness of about 0.55 mm. Consequently, the thickness E6 of the second portion b2 is about 2.7 mm.

(30) Furthermore, the third portion b3 comprises for example two large diameter biaxial carbon braids T2, two small diameter biaxial carbon braids T1 with a thickness of about 0.55 mm. Consequently, the thickness E7 of the third portion b3 is about 2.2 mm.

(31) Finally, the thickness E5 of the upstream composite wall 30b at the bend may for example be about 1.6 mm.

(32) Furthermore, FIG. 5 contains a partial perspective view illustrating a variant embodiment of the outlet pipe 30 from the hub 10 of the intermediate casing 11 according to the invention described above with reference to FIGS. 2, 3 and 4.

(33) In this example, the outer annular shroud 14 (not shown on FIG. 5) does not have an annular boss. The outlet pipe 30 thus couples to the outer annular shroud 14 without any step at the surface.

(34) More precisely, to achieve this, the outlet pipe 30 comprises an annular joggle 36 that is only partial. This joggle extends only on the two opposite edges, the upstream edge 38b and downstream edge 38a of the outlet pipe 30.

(35) The attachment of the outlet pipe 30 to the outer annular shroud 14 can be made for example using the partial annular joggle 36 by screwing through the partial annular joggle 36 to raise the composite walls 30a, 30b. The gasket 33, necessary to prevent flames from passing along the sides of the pipe 30, is thus housed between the composite walls 30a, 30b and the outer annular shroud 14.

(36) Obviously, the invention is not limited to the example embodiment that has just been described. An expert in the subject can make various modifications to it.