PRESSURE RELIEF DEVICE HAVING A PRESSURE RELIEF FLAP

Abstract

A pressure-release device has a pressure-release flap arranged in a delimiting wall of a chamber of an aircraft engine which opens in the presence of a predefined pressure in the chamber. The pressure-release flap includes a flap region and a hinge. The flap region is defined by a perforation formed in the delimiting wall which delimits the flap region with respect to a surrounding region of the delimiting wall. The perforation is formed such that, in the presence of the predefined pressure in the chamber, the flap region pivots open relative to the surrounding region, with the perforation rupturing, and the hinge is fixedly connected to the surrounding region and the flap region, such that the hinge holds the flap region on the surrounding region in the event of a rupture of the perforation and a pivoting-open of the flap region.

Claims

1. A pressure-release device having a pressure-release flap which is arranged in a delimiting wall of a chamber of an aircraft engine and which is designed to open in the presence of a predefined pressure in the chamber, wherein the pressure-release flap comprises a flap region and a hinge, wherein the flap region is defined by a perforation which is formed in the delimiting wall and which delimits the flap region with respect to a surrounding region of the delimiting wall, the perforation is formed such that, in the presence of the predefined pressure in the chamber, the flap region pivots open relative to the surrounding region of the delimiting wall, with the perforation rupturing, and the hinge is fixedly connected to the surrounding region of the delimiting wall and the flap region, such that the hinge holds the flap region on the surrounding region of the delimiting wall in the event of a rupture of the perforation and a pivoting-open of the flap region.

2. The device according to claim 1, wherein the perforation comprises a multiplicity of holes which are arranged in a line and which extend all the way through the delimiting wall.

3. The device according to claim 2, wherein the holes of the perforation have the same size and the same spacing to one another.

4. The device according to claim 2, wherein the holes of the perforation have a diameter which lies in the range between 50 m and 2 mm.

5. The device according to claim 1, wherein the delimiting wall comprises multiple material layers, wherein the perforation extends through all of the material layers.

6. The device according to claim 1, wherein the hinge is composed of a different material than the delimiting wall.

7. The device according to claim 1, wherein the hinge has at least one material ply which is of areal form and which is connected on the one hand to the flap region and on the other hand to the surrounding region.

8. The device according to claim 7, wherein the material ply is in the form of an elongate material strip, wherein the material strip is connected, along one longitudinal edge thereof and adjacent thereto, to the flap region and, along the other longitudinal edge thereof and adjacent thereto, to the surrounding region, and wherein the flap region and the surrounding region are rectilinearly adjacent to one another in the portion that is covered by the elongate material strip.

9. The device according to claim 7, wherein the hinge has at least one material ply composed of a composite material.

10. The device according to claim 9, wherein the hinge has a material ply composed of an aramid-fiber-reinforced composite material.

11. The device according to claim 1, wherein the delimiting wall including the flap region is formed by a carbon-fiber-reinforced plastic or a glass-fiber-reinforced plastic.

12. The device according to claim 9, wherein the at least one material ply composed of a composite material and the delimiting wall have been cured simultaneously in a plastics matrix.

13. The device according to claim 9, wherein the at least one material ply composed of a composite material has been retroactively connected to the flap region and to the surrounding region of the delimiting wall.

14. The device according to claim 1, wherein the delimiting wall including the flap region is formed by a metal or a metal alloy.

15. The device according to claim 1, wherein the perforation also extends in that region of the delimiting wall in which the hinge is connected to the surrounding region of the delimiting wall and to the flap region, wherein the perforation is covered in this region by the hinge.

16. The device according to claim 1, wherein the hinge is formed on the inner side of the delimiting wall.

17. The device according to claim 1, wherein the pressure-release flap has the shape of a polygon, wherein the hinge is formed or arranged at one of the sides of the polygon, and the perforation runs along the sides of the polygon.

18. The device according to claim 1, wherein the pressure-release flap has a curved delimiting line, wherein the perforation runs in a curved manner.

19. The device according to claim 1, wherein the delimiting wall forms an outer surface of the chamber of the aircraft engine.

20. An engine nacelle having a pressure-release device according to claim 1, wherein the chamber is formed in the engine nacelle and the delimiting wall in which the pressure-release flap is formed forms an outer surface of the engine nacelle.

Description

[0030] The invention will be explained in more detail below on the basis of a plurality of exemplary embodiments with reference to the figures of the drawing. In the drawing:

[0031] FIG. 1 shows a sectional side view of a gas turbine engine in which the present invention can be realized;

[0032] FIG. 2 shows a schematic perspective view of a pressure-release flap which is formed by means of a perforation in a delimiting wall of a chamber and which comprises a flap region and a hinge;

[0033] FIG. 3 shows a sectional illustration of the pressure-release flap of FIG. 2, wherein the pressure-release flap is illustrated in the closed state;

[0034] FIG. 4 shows a sectional illustration of the pressure-release flap of FIG. 2, wherein the pressure-release flap is illustrated in the open state; and

[0035] FIG. 5 shows an exemplary embodiment of a delimiting wall and of a flap region which have multiple material layers.

[0036] FIG. 1 illustrates a gas turbine engine 10 having a main axis of rotation 9. The engine 10 comprises an air intake 13 and a thrust fan 23 that generates two air flows: a core air flow A and a bypass air flow B. The gas turbine engine 10 comprises a core 110 which receives the core air flow A. In the sequence of axial flow, the engine core 110 comprises a low-pressure compressor 14, a high-pressure compressor 15, a combustion device 16, a high-pressure turbine 17, a low-pressure turbine 19, and a core thrust nozzle 20. An engine nacelle 28 surrounds the gas turbine engine 10 and defines a bypass duct 22 and a bypass thrust nozzle 18. The bypass air flow B flows through the bypass duct 22. The fan 23 is attached to and driven by the low pressure turbine 19 by way of a shaft 26 and an epicyclic gear box 30.

[0037] During use, the core air flow A is accelerated and compressed by the low-pressure compressor 14 and directed into the high-pressure compressor 15, where further compression takes place. The compressed air expelled from the high-pressure compressor 15 is directed into the combustion device 16, where it is mixed with fuel and the mixture is combusted. The resulting hot combustion products then propagate through the high-pressure and the low-pressure turbines 17, 19 and thereby drive said turbines, before they are expelled through the nozzle 20 to provide a certain thrust. The high-pressure turbine 17 drives the high-pressure compressor 15 by means of a suitable connecting shaft 27. The fan 23 generally provides the major part of the thrust force. The epicyclic gear box 30 is a reduction gear box.

[0038] It is noted that the terms low-pressure turbine and low-pressure compressor as used herein can be taken to mean the lowest pressure turbine stage and the lowest pressure compressor stage (that is to say not including the fan 23) respectively and/or the turbine and compressor stages that are connected to one another by the connecting shaft 26 with the lowest rotational speed in the engine (that is to say not including the gear box output shaft that drives the fan 23). In some documents, the low-pressure turbine and the low-pressure compressor referred to herein may alternatively be known as the intermediate-pressure turbine and intermediate-pressure compressor. Where such alternative nomenclature is used, the fan 23 can be referred to as a first compression stage or lowest-pressure compression stage.

[0039] Other gas turbine engines in which the present disclosure can be used may have alternative configurations. For example, such engines may have an alternative number of compressors and/or turbines and/or an alternative number of connecting shafts. By way of a further example, the gas turbine engine shown in FIG. 1 has a split flow nozzle 20, 22, meaning that the flow through the bypass duct 22 has its own nozzle that is separate from and radially outside the core engine nozzle 20. However, this is not restrictive, and any aspect of the present disclosure can also apply to engines in which the flow through the bypass duct 22 and the flow through the core 110 are mixed or combined before (or upstream of) a single nozzle, which may be referred to as a mixed flow nozzle. One or both nozzles (whether mixed or split flow) can have a fixed or variable area. Although the example described relates to a turbofan engine, the disclosure can be applied, for example, to any type of gas turbine engine, such as, for example, an open rotor engine (in which the fan stage is not surrounded by an engine nacelle) or a turboprop engine. In some arrangements, the gas turbine engine 10 may not comprise a gear box 30.

[0040] The geometry of the gas turbine engine 10, and components thereof, is/are defined by a conventional axis system, comprising an axial direction (which is aligned with the rotation axis 9), a radial direction (in the bottom-to-top direction in FIG. 1), and a circumferential direction (perpendicular to the view in FIG. 1). The axial, radial and circumferential directions run so as to be mutually perpendicular.

[0041] What is of importance in the context of the present invention is the configuration of pressure-release flaps which delimit chambers or compartments, which are charged with a pressure, in the gas turbine engine, wherein the pressure-release flaps automatically open in the event of a defined limit pressure being exceeded. Such chambers may be formed in the interior and/or at the outer side of the gas turbine engine. They are for example adjacent to the outer skin of the engine nacelle 21 and, here, form a partial region of said outer skin. Alternatively, they are formed for example in chambers which extend between the core engine 11 and the bypass duct 22.

[0042] FIGS. 2-4 show, in a perspective view and in sectional illustrations, an exemplary embodiment of a pressure-release device which comprises a pressure-release flap 1. The pressure-release flap 1 comprises a flap region 11 and a hinge 12.

[0043] The flap region 11 is defined by a perforation 4 which is formed in a delimiting wall 2. The delimiting wall 2 delimits a chamber 3 which is pressurized, wherein it is the intention for the pressure not to exceed a defined limit pressure, cf. FIGS. 3 and 4. The chamber 3 comprises further delimiting walls, which are however not illustrated. By means of the perforation 4, the delimiting wall 2 is divided into the flap region 11 and a surrounding region 21, which surrounds the flap region 11.

[0044] The perforation 4 is formed by a multiplicity of holes 40 arranged in a line. Said holes have the same size and the same spacing to one another. Alternatively, size and/or spacing may vary. The size of the holes 40 lies for example in the range between 50 m and 2 mm. In the exemplary embodiment illustrated, the pressure-release flap 1 is of approximately rectangular form, though this is not imperative. The perforation 4 is accordingly formed by in each case rectilinear portions, which together form a rectangle or generally a polygon.

[0045] The delimiting wall 2 including the flap region 11 is composed for example of a carbon-fiber-reinforced plastic or a glass-fiber-reinforced plastic.

[0046] The hinge 12 is fixedly connected both to the flap region 11 and to the surrounding region 21. Said hinge is formed by an areal material strip 120 which is composed of an aramid-fiber-reinforced composite material. The areal material strip 120 has two longitudinal edges 121, 122. Along one longitudinal edge 121 thereof and adjacent thereto, the material strip 120 is fixedly connected to the flap region 11. Along the other longitudinal edge 122 thereof and adjacent thereto, the material strip 120 is fixedly connected to the surrounding region 21. At the same time, it is the case that the flap region 11 and the surrounding region 21 run rectilinearly, and are rectilinearly adjacent to one another at the end sides, in the region that is covered by the hinge 12. The delimiting line 41 between the flap region 11 and the surrounding region 21 thus also defines the pivot axis 123 of the hinge 12, cf. FIG. 2.

[0047] As can be seen from FIGS. 3 and 4, the perforation 4 also runs in that region of the delimiting wall 2 in which the hinge 12 is arranged. Here, the perforation 4 is covered in this region by the material strip 120.

[0048] The connection between the hinge 12, on the one hand, and the flap region 11 and the surrounding region 21, on the other hand, may be realized for example by means of adhesive materials. Here, the hinge is produced as a separate part and is subsequently connected to the flap region 11 and to the surrounding region 21. Alternatively, the hinge 12 and the delimiting wall 2 are produced jointly, wherein a common plastics matrix is used in which aramid fibers of the hinge 12 and glass fibers or carbon fibers of the delimiting wall 2 cure, such that both material plies cure jointly and thereby connect to one another. The flap region 11 and the surrounding region 21 are formed by subsequent perforation.

[0049] The device functions as follows. If the pressure in the chamber 3 reaches a predefined pressure, the perforation 4 ruptures. For this purpose, the perforation 4 is provided with openings 40 such that it ruptures in the presence of the predefined pressure. Here, the flap region 11 pivots open relative to the surrounding region 21, such that a passage opening 6 is formed in the delimiting wall 2, via which passage opening the pressurized gas 7 can be discharged from the chamber 3 into the surroundings.

[0050] In the region of the hinge 12, however, the flap region 11 remains fixedly connected to the surrounding region 21 of the delimiting wall 2 by means of the hinge 12. The flap region 11 is thus held on the surrounding region 21 by means of the hinge 12 in the event of a rupture of the perforation 4, and cannot detach from the delimiting wall 2.

[0051] An alternative refinement provides for the delimiting wall 2 including the flap region 11 to be composed of a metal or of a metal alloy. For this case, provision may furthermore be made whereby the hinge 12 is also composed of a metal or of a metal alloy, wherein the metal or the metal alloy of which the hinge 21 is composed has sufficient ductility in order to deform during a pivoting-open of the flap region 11.

[0052] A further refinement is illustrated in FIG. 5. In said refinement, the delimiting wall 2 has a multiplicity of material layers 201, 202, 203. Correspondingly, the flap region 11 also comprises multiple material layers 111, 112, 113. Here, provision is made whereby the perforation 4 extends through all of the material layers. The hinge 12 is composed of one material ply, as is likewise the case in the exemplary embodiment of FIGS. 2-4. Alternatively, the hinge 12 may likewise be composed of a multiplicity of material plies, both in the exemplary embodiment of FIG. 5 and in the exemplary embodiment of FIGS. 2-4.

[0053] It will be understood that the invention is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the concepts described herein. Furthermore, except where mutually exclusive, any of the features may be used separately or in combination with any other features, and the disclosure extends to and includes all combinations and sub-combinations of one or more features that are described herein. If ranges are defined, said ranges thus comprise all of the values within said ranges as well as all of the partial ranges that lie in a range.