Guide vane segment

Abstract

The invention relates to a guide vane segment (10) for a gas turbine, in particular an aircraft engine (1), comprising a plurality of guide vanes (20), a radially outer cover band (30) connecting the plurality of guide vanes (20), wherein stiffening elements (40) integral to and / or integrated into the cover band (30) are arranged on a radial outer surface (31) of the cover band (30).In order to better reduce dynamic loads during the operation of the gas turbine, it is proposed that the stiffening elements (40) form an extension of the guide vanes (20) in the radial direction (R), and / or that a contour of the stiffening elements (40) on the outside (31) of the shroud (30) lies within an outer contour (A) formed by a band (B) around a projection (P) of outlines (21) of the guide vane (20) on a radial inside (32) onto the outside (31) of the shroud (30), wherein a width (b) of the band (B) in the circumferential direction (U) around the projection is at most 20% of the thickness (d) of the projection (P) in the circumferential direction (U).

Description

[0001] The invention relates to a guide vane segment for a compressor of a gas turbine, in particular of an aircraft engine, comprising a plurality of guide vanes, a radially outer cover band connecting the plurality of guide vanes, wherein stiffening elements integral to and / or integrated into the cover band are arranged on a radial outer side of the cover band.

[0002] Guide vane segments can have reinforcing and / or stiffening elements on the outer surface of their shroud to absorb or modulate vibrations during gas turbine operation, thereby increasing the guide vane segment's service life. The stiffening elements can be integrally bonded to the shroud. The guide vane segments are typically cast and subsequently post-treated.

[0003] For example, US patent 10,876,416 B2 shows a guide vane segment with ribs extending along its outer surface on the shroud. Projections of the guide vane chords intersect these ribs on the shroud. This is intended to reduce the dynamic load on the guide vane segments.

[0004] In contrast, an object of the invention is to provide a guide vane segment that can better reduce dynamic loads during the operation of the gas turbine.

[0005] The problem is solved according to the invention by a guide vane segment according to claim 1.

[0006] A guide vane segment according to the invention for a gas turbine, in particular an aircraft engine, comprises a plurality of guide vanes, a radially outer cover band connecting the plurality of guide vanes, wherein stiffening elements integral to and / or integrated into the cover band are arranged on a radial outer side of the cover band.

[0007] The problem is solved by the guide vane segment according to claim 1 in that the stiffening elements form an extension of the guide vanes in the radial direction, and / or that a contour of the stiffening elements lies on the outside of the cover strip within an outer contour formed by a band around a projection of outlines of the guide vane on a radial inside onto the outside of the cover strip, wherein a width of the band in the circumferential direction around the projection is a maximum of 20% of the thickness of the projection in the circumferential direction.

[0008] By using stiffening elements that each form an extension of the guide vane and / or by using stiffening elements with a contour that, as described, is based on a projection of the guide vanes, an even better reduction of the dynamic load on the guide vane segment is advantageously achieved. In particular, vibrations can be ideally damped, so that component fatigue occurs later than with conventional guide vane segments.

[0009] The guide vane segment can preferably be provided for a compressor. Alternatively, the guide vane segment can be provided for a turbine. The guide vane segment can be a segment of a guide vane ring of a compressor. The guide vane segment, and in particular the shroud, can be curved in the circumferential direction. The shroud can form an outer wall of a flow channel in a casing or intermediate casing of the gas turbine. The guide vanes can transition into the shroud with a fillet at a blade root area. The projection of the guide vane outline can preferably include the fillet. The shroud forms an enlarged outer contour around the projection of the guide vane and can, in other words, represent an imaginary extension of the projection within which the stiffening element runs on the shroud. The width of the shroud can also be less than 20%, in particular a maximum of 10% of the thickness of the projection in the circumferential direction.

[0010] The radial inner surface of the cover strip corresponds to an outer wall of the flow channel. Exactly one stiffening element can be provided for each of the guide vanes.

[0011] Further advantages and features will become apparent from the following description of some preferred embodiments and the dependent claims.

[0012] According to an advantageous embodiment of the invention, the stiffening elements can be spaced apart from one another in the circumferential direction. This allows the local stresses due to vibrations to be influenced particularly favorably.

[0013] According to a further advantageous embodiment of the invention, the stiffening elements can be designed as ribs and / or beads. Ribs or beads can be arranged as raised, narrow strips or ridges on the outside of the cover strip. This advantageously increases the stiffness and strength of the cover strip without adding significant additional weight.

[0014] According to a preferred embodiment of the invention, a connecting element can be arranged between two adjacent stiffening elements and be formed integrally to and / or integrated into the cover strip on a radial outer surface. These additional stiffeners also allow for better damping of circumferential bending of the cover strip.

[0015] According to a further preferred embodiment of the invention, the stiffening elements and the connecting elements can form a common stiffening structure on the cover strip; in particular, all stiffening elements and all connecting elements can form a single common stiffening structure on the cover strip. This achieves particularly good stiffening of the cover strip with only a small amount of added material.

[0016] According to a particularly preferred embodiment, the stiffening elements can have a lateral inward curve at least over a portion of their longitudinal extent, in particular where the inward curve can form an undercut. The inward curve advantageously saves material and thus weight. The inward curve can be a recess in the stiffening element, extending in particular in the circumferential direction. The inward curve can be arranged on a side surface of the stiffening element that extends substantially in the axial direction. The inward curve can extend to a base of the stiffening element. An undercut can be formed, in particular, within the inward curve. The undercut can be formed without direct access to the outer side surface of the stiffening element and, in particular, can be formed within the inward curve in addition to the inward curve itself.

[0017] In a further development, the stiffening elements may be conical in the radial direction, or they may have a T-shaped cross-section perpendicular to the axial direction. In particular, a lateral inward curvature may be formed on both sides of one or more of the stiffening elements when viewed circumferentially, resulting in a T-shaped structure. The cross-sections of the stiffening elements may be rectangular, partially elliptical, conical, or frustoconical.

[0018] Particularly preferably, the shroud can have a radially outwardly projecting connecting structure in the region of a leading edge of the guide vanes, wherein at least one or all of the stiffening elements begin in an axially forward region of the shroud in the axial direction at or behind the connecting structure between 0% and 50% of the axial shroud extension. This allows the guide vane segment to be advantageously tuned to vibration modes. The stiffening elements can begin at different points behind the connecting structure. The connecting structure can serve as a connection to a housing of a flow channel in which the guide vanes of the guide vane segment are arranged. The connecting structure can extend circumferentially in the region of the leading edges of the guide vanes along the entire shroud.

[0019] Furthermore, the shroud can have a rear connecting structure projecting radially outwards in the region of a trailing edge of the guide vanes, and the stiffening structure can terminate axially at or on the rear connecting structure. The rear connecting structure can extend circumferentially in the region of the trailing edges of the guide vanes, particularly along the entire shroud. The stiffening elements can be arranged between the connecting structures.

[0020] Furthermore, in another embodiment, the cover strip can have a front connecting structure projecting radially outwards in the region of a leading edge of the guide vanes, and the cover strip can have a rear connecting structure projecting radially outwards in the region of a trailing edge of the guide vanes, wherein a groove with a maximum radial groove depth is formed between the front connecting structure and the rear connecting structure, and wherein the maximum height of the stiffening elements in the groove, measured from a groove base, can correspond to a maximum of 100%, in particular a maximum of 50%, preferably 40%, of the radial groove depth. The radial groove depth can be measured, in particular, at the shallower of the two connecting structures, and especially preferably at a radially outermost point of the shallower connecting structure adjacent to the groove.This allows the guide vane segment to be manufactured with a low weight and ensures that its installation height in the outer area of ​​the engine casing remains low. Furthermore, a significant improvement in the dynamic loads on the guide vane segment can be achieved advantageously through the use of stiffening elements with low radial heights.

[0021] Another aspect of the present invention relates to a compressor for an aircraft engine comprising a guide vane segment as described above.

[0022] Another aspect of the present invention relates to an aircraft engine with a compressor and / or a guide vane segment as described above.

[0023] The invention is explained in more detail with reference to the following drawings and some preferred embodiments of the invention. Fig. 1 shows a schematic representation of an embodiment of an aircraft engine. Fig. 2 shows an embodiment of a guide vane segment according to the invention in a top view. Fig. 3 shows an embodiment of the guide vane segment according to the invention in a meridional section. Fig. 4 shows cross-sections of possible embodiments of the stiffening elements.

[0024] In Fig. 1Figure 1 schematically depicts a gas turbine configured as an aircraft engine 1 in a meridional section. The aircraft engine 1 has an engine inlet 1a, from which a bypass channel 1b and a flow channel 1c, serving as the core flow channel 1c, flow downstream. The bypass channel 1b serves to generate thrust, while the flow channel 1c primarily serves to generate energy for the components of the aircraft engine 1 and for cabin systems of an aircraft. The main components of the aircraft engine 1 are arranged sequentially in the flow direction within the flow channel 1c, namely a compressor 2, a combustion chamber 3, and a turbine 4. The aircraft engine 1 has an engine outer casing 6 surrounding the engine inlet 1a and the overall bypass channel 1b, and an intermediate casing 7 separating the overall bypass channel 1b and the flow channel 1c, with the intermediate casing 7 serving as the outer casing 7 of the flow channel 1c.A fan 5 with one or more fan stages for drawing in and initially compressing air can be arranged in the engine inlet 1a. The fan 5, the compressor 2, and the turbine 4 are mechanically coupled by means of at least one shaft 8 rotating about an engine axis 8a. The fan 5 and, optionally, also (not shown) forward low-pressure compressor stages can be decoupled from the faster-rotating turbine 4, in particular from a low-pressure turbine, by a gearbox 9. A portion of the air drawn in and compressed by the fan 5 flows into the flow channel 1c, where it is strongly compressed by the compressor 2 in order to be mixed with fuel and ignited in the combustion chamber 3 and finally to expand in the turbine 4 to drive the at least one shaft 8.

[0025] The engine rotation axis 8a serves as a reference axis for defining an axial direction Ax running parallel to the engine rotation axis 8a, a radial direction R perpendicular to it, and a circumferential direction U running around the engine rotation axis 8a.

[0026] The compressor 2 has a guide vane segment 10 according to the invention, which is based on the Figs. 2 and 3 will be described in more detail below.

[0027] Fig. 2 The embodiment of the guide vane segment 10 according to the invention is shown in a top view. Fig. 3 Figure 1 shows the embodiment of the guide vane segment 10 according to the invention in a section along a longitudinal extension of the stiffening elements 40 or the guide vanes 20.

[0028] In this embodiment, the guide vane segment 10 comprises six guide vanes 20, i.e., a plurality of guide vanes 20 arranged side by side in a row in the circumferential direction U. A guide vane segment 10 can also contain more or fewer guide vanes 20. At their radial outer ends, the guide vanes 20 are connected to one another by a cover band 30 on its radial inner surface 32. In the illustration in Fig. 2 are the guide vanes 20 concealed and their outlines 21 resulting on an inner side 32 of the cover band 30 as a projection P onto a surface in the Fig. 2 The outer surface 31 of the cover band 30 is shown. The outlines 21 are represented as elongated dashed lines.

[0029] In a region of a leading edge 22 of the guide vanes 20, a front connecting structure 33 is arranged on the outer surface 31 of the shroud 30, and in a region of a trailing edge 23 of the guide vanes 20, a rear connecting structure 34 is arranged on the outer surface 31 of the shroud 30. The connecting structures 33, 34 serve to connect the guide vane segment 10 to a housing, in particular an intermediate housing 7 of the flow channel 1c. A groove 35 is formed between the connecting structures 33, 34, in which stiffening elements 40 and connecting elements 42, which connect the connecting elements in the circumferential direction U, are arranged to stiffen the shroud 30 and to dampen and thus reduce the dynamic load on the guide vane segment 10.

[0030] According to the invention, the stiffening elements 21 can be formed as an extension of the guide vanes 20 and / or it can be provided that a contour of the stiffening elements 40 lies on the outside 31 of the cover band 30 within an outer contour A formed by a band B around the projection P of the outlines 21 of the guide vane 20 on a radial inside 32 onto the outside 31 of the cover band 30, wherein a width b of the band B in the circumferential direction U around the projection is a maximum of 20% of the thickness d of the projection P in the circumferential direction U.

[0031] The bands B are each represented by short dashed lines and run around or in the circumferential direction U in front of and behind a projected outline 21 of one of the guide vanes 20 on the outer surface 31 of the cover band 30. A band B represents an additional area into or over which parts of the stiffening elements 40 can project and / or in which the parts of the stiffening elements 40 are formed.

[0032] The cover band 30 can have an axial cover band extent 30 E_Ax in the axial direction Ax. The stiffening elements 40 can begin behind the front connecting structure 33 at a distance between 0% and 50% of the axial cover band extent 30 E_Ax. In other words, the stiffening elements 40 can be directly adjacent to the front connecting structure 33 or spaced from it at a distance between 0% and 50% of the axial cover band extent. Additionally, the stiffening elements 40 can begin in front of the rear connecting structure 34 at a distance between 0% and 20% of the axial cover band extent. The front connecting structure 33 can have a slope 37 sloping in the axial direction Ax, on or at which the stiffening element 40 can be arranged with a front end. The rear connecting structure 33 can have an axially rising slope 38 on which the stiffening element 40 can be arranged with a rear end.

[0033] The stiffening elements 40 can be spaced apart from each other in the circumferential direction U, which advantageously reduces the amount of stiffening mass required on the cover strip 30. The distance between adjacent stiffening elements 40 can correspond to the distance between adjacent guide vanes 20, or the distance between adjacent stiffening elements 40 can correspond to the distance between adjacent guide vanes 20 less at most a width b of the strip B. The stiffening elements 40 are as shown in the Figs. 2 and 3The stiffening elements 40 are shown as ribs, which can extend, in particular, in a bead-like fashion from the area at the leading edge 22 of the guide vanes 20 to the area at the trailing edge 23. The shape of the stiffening elements 40 can be determined on the basis of a strength calculation, for example by means of a finite element method or a similar simulation, and can be provided with a free-form cross-section, whereby the free-form does not necessarily have to correspond to a basic geometric element such as a rectangle, a cone, a semicircle, a partial ellipse, or a combination of these elements. However, it can be provided that the stiffening elements 40 are conical in the radial direction R, or that the stiffening elements 40 have a T-shaped cross-section perpendicular to the axial direction Ax. This cross-section can also be a free-form shape.The stiffening elements 40 are integrally connected to the cover strip 30. An additive manufacturing process can be used to produce a stiffening element 40.

[0034] Adjacent stiffening elements 40 can be connected by a connecting element 42, wherein a connecting element 42 can, for example, be a rib or bead extending between the two adjacent stiffening elements 40. In the present embodiment, the connecting element 42 has a U-shaped structure. The connecting element 42 can, in particular, extend in or quasi-in the circumferential direction U. The connecting element 42, especially in a section central in the circumferential direction U, can also extend transversely or quasi-transversely to a longitudinal extension of one or both adjacent stiffening elements 40. The connecting elements 42 can also be designed as a free-form shape.It may be provided that the stiffening elements 40 and the connecting elements 42 form a common stiffening structure 44 on the cover strip 30, in particular that all stiffening elements 40 and all connecting elements 42 form a single common stiffening structure 44 on the cover strip 30.

[0035] As in Fig. 3 As shown, for example, an internal curvature 41 extending from front to back can be formed laterally on the stiffening element 40. This internal curvature 41 advantageously does not reduce the stiffness of the stiffening element 40 to a significant extent, but allows less material to be used for the stiffening element 40, which advantageously leads to a lower weight. A stiffening element 40 can have the lateral internal curvature 41 at least over part of its longitudinal extent 40 E_Ax, wherein, in particular, the internal curvature 41 can form an undercut.

[0036] Furthermore, as in Fig. 3 As shown, the groove 35 has a groove depth t, wherein the maximum height h of the stiffening elements 40 in the groove 35, measured from a groove base 36, can correspond to a maximum of 100%, in particular a maximum of 50%, preferably 40%, of the radial groove depth t. The maximum groove depth t can be measured from the outermost radial point of the shallower of the two connecting structures 33, 34 to the deepest point of the groove base 36.

[0037] In Fig. 4 Some exemplary cross-sections of the stiffening elements 40 are shown on the cover strip 30. Furthermore, the maximum heights h of the corresponding shapes are also shown, which are each less than those in Fig. 3 shown groove depth t.

[0038] The top row shows four different basic shapes that can represent a cross-section of the stiffening elements 40 in the axial direction Ax. From left to right, these are a rectangle, a semi-ellipse (in particular a semicircle), a triangle, and a truncated cone.

[0039] Accordingly, the cross-sections can be rectangular, partially elliptical, conical, or truncated conical. The exact dimensions, profiles, and lengths of the sides can deviate from these basic shapes and may depend on simulations and calculations.

[0040] The lower row shows stiffening elements 40 with rectangular base shapes and lateral inward curves 41. The first illustration shows a stiffening element 40 with a rectangular base shape and a centrally located inward curve 41. The second illustration shows a stiffening element 40 with a rectangular base shape and an inward curve 41 extending along the cover strip. The third illustration shows a stiffening element 40 with a rectangular base shape and inward curves 41 extending on both sides, thus forming an example of a T-shaped cross-section. The fourth illustration shows the embodiment of the first illustration with an additional undercut 43 in the lateral inward curve 41 of the stiffening element 40. The exact dimensions, profiles, and lengths of the sides, the inward curve, and the undercut may deviate from these base shapes and may depend on simulations and calculations.

[0041] Overall, this results in a guide vane segment 10, the dynamic load of which is significantly reduced and its service life increased due to the stiffening elements 40 which run accordingly to the guide vanes. Reference symbol list

[0042] 1 Aircraft engine 1a Inlet 1b Bypass duct 1c Core flow duct 2 Compressor 3 Combustion chamber 4 Turbine 5 Fan 6 Outer casing 7 Intermediate casing 8 Engine shaft 8a Engine axle 9 Gearbox 10 guide vane segment 20 Guide vane 21 Outline 22 Leading edge 23 Trailing edge 30 Cover strip 31 Outer side 32 Inner side 33 Front connection structure 34 Rear connection structure 35 Groove 36 Groove bottom 37 Descending bevel 38 Ascending bevel 40 Stiffening element 41 Inward curvature 42 Connecting element 43 Undercut 44 Stiffening structure BBand bWidth of the band AOuter contour of the band PProjection of the outline of the guide vane tGroove depth hHeight of a stiffening element Ax Axial direction R Radial direction U Circular direction

Claims

1. Guide vane segment (10) for a gas turbine, in particular an aircraft engine (1), comprising a plurality of guide vanes (20), a radially outer cover band (30) connecting the plurality of guide vanes (20), wherein stiffening elements (40) integral to and / or integrated into the cover band (30) are arranged on a radial outer surface (31) of the cover band (30), characterized by that the stiffening elements (40) form an extension of the guide vanes (20) in the radial direction (R), and / or that a contour of the stiffening elements (40) on the outside (31) of the cover band (30) lies within an outer contour (A) formed by a band (B) around a projection (P) of outlines (21) of the guide vane (20) on a radial inside (32) onto the outside (31) of the cover band (30), wherein a width (b) of the band (B) in the circumferential direction (U) around the projection is a maximum of 20% of the thickness (d) of the projection (P) in the circumferential direction (U).

2. Guide vane segment according to claim 1, characterized by that the stiffening elements (40) are spaced apart from each other in the circumferential direction (U).

3. Guide vane segment according to one of the preceding claims, characterized by that the stiffening elements (40) are designed as ribs and / or beads.

4. Guide vane segment according to one of the preceding claims, characterized by that a connecting element (42) is arranged between two adjacent stiffening elements (40) and is integral to and / or integrated into the cover band (30) on a radial outer surface (31) of the cover band (30).

5. Guide vane segment according to claim 4, characterized by thatthe stiffening elements (40) and the connecting elements (42) form a common stiffening structure (44) on the cover strip (30), in particular that all stiffening elements (40) and all connecting elements (42) form a single common stiffening structure (44) on the cover strip (30).

6. Guide vane segment according to one of the preceding claims, characterized by that the stiffening elements (40) at least over part of their longitudinal extent (40 E_Ax ) have a lateral inward curve (41), in particular wherein the inward curve (41) can form an undercut (43).

7. Guide vane segment according to one of the preceding claims, characterized by that the stiffening elements (40) are conically shaped in the radial direction (R), or that the stiffening elements (40) have a T-shaped cross-section perpendicular to the axial direction (Ax).

8. Guide vane segment according to one of the preceding claims, characterized by that the cover band (30) in the area of ​​a leading edge (22) of the guide vanes (20) has a front radially outward projecting connecting structure (33), and that at least one or all of the stiffening elements (30) in an axially forward region of the cover band (30) in the axial direction (Ax) on or behind the connecting structure (33) between 0% and 50% of the axial cover band extension (30 E_Ax ) begins.

9. Guide vane segment according to claim 8, characterized by that the cover band (30) in the area of ​​a trailing edge (23) of the guide vanes (20) has a rear radially outward projecting connecting structure (33), and that the stiffening structure (30) ends in the axial direction at or on the rear connecting structure (34).

10. Guide vane segment according to one of the preceding claims, characterized by thatthe cover band (30) in the region of a leading edge (22) of the guide vanes (20) has a front radially outward projecting connection structure (33), that the cover band (30) in the region of a trailing edge (23) of the guide vanes (20) has a rear radially outward projecting connection structure (33), and wherein a groove (35) with a maximum radial groove depth (t) is formed between the front connection structure (33) and the rear connection structure (34), and wherein a maximum height (h) of the stiffening elements (40) in the groove (35) measured from a groove base (36) corresponds to a maximum of 100%, in particular a maximum of 50%, preferably 40%, of the radial groove depth (t).

11. Compressor (2) for an aircraft engine (1) comprising a guide vane segment according to one of the preceding claims.

12. Aircraft engine (1) with a compressor (2) according to claim 11 and / or with a guide vane segment (10) according to any one of claims 1 to 10.

Images