CONNECTION SYSTEM FOR HOUSING ELEMENTS OF A TURBINE INTERMEDIATE CASING

Abstract

A connection system for a hot gas-conducting annular duct of a turbine intermediate casing of a gas turbine includes a first housing element, a second housing element situated next to the first housing element in the circumferential direction, and a fastening unit configured for connecting the first housing element and the second housing element to one another at edges adjacent to one another in the circumferential direction, the fastening unit including a clamping element which is mounted on the one housing element with the aid of a connection, the clamping element resting on a clamping surface provided on the other housing element in such a way that the other housing element is accommodated between the clamping element and the one housing element. It is provided that the top side of the clamping surface facing the clamping element has a clamping surface contour—relative to a longitudinal section which extends along, in particular essentially in parallel to the adjacent edges of the two housing elements—which is designed in such a way that it thwarts a rotation of the clamping element about an axis of the connection.

Claims

1. A connection system for a hot gas-conducting annular duct of a turbine intermediate casing of a gas turbine, the connection system comprising: a first housing element; a second housing element situated next to the first housing element in a circumferential direction; and a fastening unit configured for connecting the first housing element and the second housing element to one another at adjacent edges of the first housing element and of the second housing element adjacent to one another in the circumferential direction, the fastening unit including a clamp mounted on the second housing element with the aid of a connection, in particular a bolt-nut connection, the clamp resting on a clamping surface provided on the first housing element in such a way that the first housing element is accommodated between the clamp and the second housing element; a top side of the clamping surface facing the clamp has a clamping surface contour, relative to a longitudinal section extending along the adjacent edges, designed in such a way to thwart a rotation of the clamp about an axis of the connection.

2. The connection system as recited in claim 1 wherein the clamping surface contour has at least one clamping surface contour section with a slope differing from a further slope of a surface contour of a surface section of the first housing element surrounding the clamping surface.

3. The connection system as recited in claim 2 wherein the clamping surface contour is a straight line slanted relative to a straight line of the surface contour, the line of the clamping surface contour and the line of the surface contour forming an angle of 0.7° to 1.7°.

4. The connection system as recited in claim 3 wherein the angle is 1.0° to 1.4°.

5. The connection system as recited in claim 2 wherein the clamping surface contour has at least one curved line section in such a way that a distance between the clamping surface contour and the surface contour increases.

6. The connection system as recited in claim 1 wherein a clamping section of the clamp resting on the clamping surface is spherical, a contact point being formed between the clamp and the clamping surface.

7. The connection system as recited in claim 1 wherein the connection system is an aircraft gas turbine connection system.

8. The connection system as recited in claim lwherein the first housing element is one of a panel of a turbine intermediate casing and a fairing of a turbine intermediate casing, and the second housing element is the other of the panel and the fairing.

9. The connection system as recited in claim 1 wherein the first housing element is a panel of a turbine intermediate casing and the second housing element is a fairing of a turbine intermediate casing.

10. The connection system as recited in claim 1 wherein the connection is a bolt-nut connection.

11. The connection system as recited in claim 1 wherein the longitudinal section extends parallel to the adjacent edges.

12. A turbine intermediate casing for a gas turbine, the turbine intermediate casing comprising: a hot gas-conducting annular duct formed by multiple housing elements situated next to one another in the circumferential direction, the annular duct being delimited in the circumferential direction by radially inner housing elements and radially outer housing elements, multiple strut lining elements, extending between the inner housing elements and the outer housing elements, being distributed in the circumferential direction and extending through the annular duct in the radial direction, and the inner housing elements and the outer housing elements each being formed by multiple first housing elements and multiple second housing elements, wherein the turbine intermediate casing includes at least one connection system as recited in claim 1.

13. The turbine intermediate casing as recited in claim 12 wherein a first housing element of the multiple housing elements and a second housing element of the second housing elements are connected to one another via multiple fastening units distributed in the axial direction.

14. The turbine intermediate casing as recited in claim 13 wherein the number of multiple fastening units is three.

15. The turbine intermediate casing as recited in claim 12 wherein in the case of radially outer housing elements, a last fastening unit in the flow direction has a clamping surface contour thwarting the rotation of the clamp.

16. The turbine intermediate casing as recited in claim 12 wherein in the case of radially inner housing elements, a first fastening unit in the flow direction has a clamping surface contour thwarting the rotation of the clamp.

17. An aircraft gas turbine comprising the turbine intermediate casing as recited in claim 12.

Description

DETAILED DESCRIPTION

[0030] FIG. 1 shows, schematically and in a simplified manner, a first housing element 10 of a turbine intermediate casing which is not represented further. First housing element 10 may also be referred to as a so-called panel. First housing element 10 adjoins, in circumferential direction UR, a second housing element 12 which is merely indicated. Second housing element 12 may be, for example, a so-called fairing, i.e., a housing component which, on the one hand, delimits the hot gas-conducting annular duct of the turbine intermediate casing and, on the other hand, surrounds struts or lines extending through this annular duct.

[0031] First housing element 10 includes multiple clamping surfaces 16 on each of its edges 14 which are situated opposite one another in circumferential direction UR. Preferably, three clamping surfaces 16 are provided along a particular edge 14. On second housing element 14, clamping elements 20, only one of which is depicted highly simplified, are mounted on particular edges 18. Clamping elements 20 are preferably fastened on second housing element 18 with the aid of a bolt-nut connection 22 which is depicted here in a simplified manner as a circle. One clamping element 20 and one assigned clamping surface 16 may also be referred to as one fastening unit which is used for connecting first housing element 10 and second housing element 12 to one another. The fastening units are designed, in particular, in such a way that clamping surfaces 16 are accommodated between clamping element 20 and an edge of second housing element 12, which is not visible in the representation.

[0032] FIG. 2 shows a partial sectional representation along intersection line II-II which extends along or essentially in parallel to edge 14 of first housing element 10. Cut clamping surface 16 is the last clamping surface—downstream in the axial direction—on first housing element 10. FIG. 2 shows first housing element 10 including clamping surface 16 in the embodiment known so far. In this case, clamping surface contour 24 of clamping surface 16 is essentially parallel to a surface contour 26—which surrounds clamping surface 16—of first housing element 10 or its edge 14. In FIG. 2, a rectangle formed by a dotted line indicates an area which is depicted in FIGS. 3A and 3B in an enlarged view, FIGS. 3A and 3B representing specific embodiments of the present invention.

[0033] Clamping surface 16 is depicted in an enlarged view in FIGS. 3A and 3B. A dotted line represents the known course of clamping surface contour 24, which is apparent in FIG. 2.

[0034] In FIG. 3A, clamping surface 16 has a changed clamping surface contour 24a which is slanted relative to surrounding surface contour 26. The slant represented in FIG. 3A is not shown correctly to scale, for illustration purposes. An angle A formed by clamping surface 16 or its clamping surface contour 24a and surface contour 26 is preferably approximately 0.7° to 1.7°, in particular in a range of 1.0° to 1.4°. On a length of the clamping surface contour of, for example, 50 mm, this corresponds to a slope of approximately 0.6 mm to 1.5 mm.

[0035] A clamping element 20 which rests with a clamping section 28 on clamping surface 14 is also represented, in a greatly simplified and schematic manner, in FIGS. 3A and 3B. The clamping section is preferably spherical, in particular designed in the manner of a spherical element, so that a contact point is formed between clamping element 20 and clamping surface 16 or clamping surface contour 24a. As is apparent in FIG. 3A, slanted clamping surface contour 24a prevents clamping element 20 from slipping in axial direction AR or prevents a rotation of the clamping element about bolt-nut connection 22 (FIG. 1). In the case of a so-called decambering of housing element 10 during operation of the gas turbine, clamping surface contour 24a moves in the direction of the position of conventional clamping surface contour 24 (dashed line). Due to the slant of clamping surface contour 24a, it may be ensured, however, despite this decambering, that slipping of clamping element 20 may also be prevented in the decambered state of housing element 10.

[0036] FIG. 3B shows one alternative specific embodiment of clamping surface contour 24b. In this example, clamping surface contour 24b has a curved or bent shape. In FIG. 3B as well, the radius of curvature is not shown to scale, for illustration purposes. The radius of curvature of clamping surface contour 24b may be the same along the entire axial length of clamping surface 16, so that clamping surface contour 24b describes a portion of a circular arc. Alternatively, sections of the radius of curvature may also be different, so that clamping surface contour 24b is designed in the shape of a parabola. The curvature is designed concavely relative to clamping element 20. As already described above with respect to the specific embodiment of FIG. 3A, the curved clamping surface contour should also be selected in such a way that the maximum slope along an exemplary length of the clamping surface contour of 50 mm is no more than approximately 0.6 mm to 1.5 mm.

[0037] A feature common to the specific embodiments of both FIGS. 3A and 3B is that they have a different slope as compared to surrounding surface contour 26. In other words, it may also be stated that the clamping surface contour (in the slanted case) or a tangent (in the curved case) applied to the clamping surface contour form, with axial direction AR or radial direction RR, a different angle than surrounding surface contour 26 of housing element 10, in particular its edge 14.

[0038] The specific embodiment represented in FIG. 3B shows a clamping surface contour 24b which is curved in such a way that a thickness of first housing element 10, in the area of clamping surface contour 24b, decreases continuously in the axial or flow direction from the upstream end of clamping surface contour 24b (on the left in FIG. 3B) toward the downstream end of clamping surface contour 24b (on the right in FIG. 3B). In one alternative specific embodiment, the clamping surface contour may also be curved in such a way, however, that a point of the smallest thickness of first housing element 10 in the area of the clamping surface contour is located approximately in the middle, in the axial or flow direction, between the upstream end of clamping surface contour 24b (on the left in FIG. 3B) and the downstream end of clamping surface contour 24b (on the right in FIG. 3B). In other words, the thickness increases toward the edge regions in the axial or flow direction of the clamping surface contour. A better rotation lock may therefore be implemented.

[0039] In the circumferential direction of first housing element 10 (orthogonally to the image plane of FIGS. 3A and 3B), the thickness of first housing element 10 preferably does not change in the area of clamping surface contour 24a, 24b. In particular cases, however, it may also be advantageous here to provide a thickness which changes in the circumferential direction.

[0040] The slant or curvature of clamping surface contour 24a, 24b may also be designed in such a way, in addition to having the effect of preventing slipping of clamping element 20, that the slant or curvature applies a type of restoring force onto the clamping element, so that the clamping element is moved into its original clamping position or into its intended relative position with respect to the clamping surface, in particular when housing element 10 transitions from a decambered state during operation of the gas turbine back into a cambered state, in particular during a standstill of the gas turbine.

[0041] The connection system presented here, which has a slanted or curved clamping surface contour, may be provided on all clamping surfaces of a first housing element. Alternatively, it is also possible that only certain clamping surfaces are designed to be slanted or curved, in particular those clamping surfaces that have been shown, from experience, to have a particularly high risk of the clamping elements slipping. The connection system presented was explained using the example of housing elements 10, 12. Such a connection system may also be used, however, on radially inner housing elements of a turbine intermediate casing.

[0042] In the case of radially outer housing elements 10, 12 (FIGS. 1, 4), the slanted or curved clamping surface contour may be provided, in particular, on the last connection system in the flow direction. In FIG. 1, this corresponds to clamping surfaces 16 represented at the top left and right of housing element 10, of which the right clamping surface is also illustrated in the sectional representation of FIGS. 2, 3A and 3B.

[0043] In the case of radially inner housing elements 30 the first fastening unit or connection system in the flow direction may have a clamping surface contour which thwarts the rotation of the clamping element. Similar to FIG. 1, this would be, for example, the clamping surfaces situated at the bottom left and right.

[0044] The slanted or curved clamping surface contour may be produced, for example, by removal of material from the conventional clamping surface. In order to prevent a weakening of the structure of the housing element, however, the slanted or curved clamping surface contour may also be produced by casting a housing element, or a contact section may be or is provided on the unmachined cast part, which is already thickened compared to the prior art, which makes it possible to create the slanted or curved clamping surface contour by mechanical secondary machining, without falling below a minimum wall thickness required for the structural stability.

[0045] FIG. 4 shows inner housing elements 30 and outer housing elements 10, 12, multiple strut lining elements 40, extending between the inner housing elements and the outer housing elements.

LIST OF REFERENCE NUMERALS

[0046] 10 first housing element [0047] 12 second housing element [0048] 14 edge [0049] 16 clamping surface [0050] 18 edge [0051] 20 clamping element [0052] 22 bolt-nut connection [0053] 24, 24a, 24b clamping surface contour [0054] 26 surface contour [0055] 28 clamping section [0056] AR axial direction [0057] RR radial direction [0058] UR circumferential direction