Guide vane segment

Abstract

The invention relates to a guide vane segment (10) for a flow channel (1c) in a compressor (2) of an aircraft engine (1), and to an aircraft engine (1) having a guide vane segment (10). The guide vane segment (10) is characterized in that at least one hook (41, 42) on a shroud (30) for fastening in the flow channel (1c) and connecting a plurality of guide vanes (20) has at least one recess (45, 46) at a hook end (43, 44), wherein the at least one recess (45, 46) divides the hook end (43, 44) along its longitudinal extent (L) in the circumferential direction (U). This advantageously reduces a cambering effect of the guide vane segment (10) during operation of the aircraft engine (1).

Description

[0001] The invention relates to a guide vane segment for a flow channel of an aircraft engine with a shroud, in particular for a compressor of an aircraft engine.

[0002] In the flow duct of a compressor in an aircraft engine, guide vanes are used to deflect the flow. The guide vanes are arranged between an inner casing and an outer casing. The outer casing can be an intermediate casing and the flow duct can be a core flow duct of the aircraft engine. The guide vanes are usually inserted individually into the casings or into a frame and then into the casing, creating gaps through which leaks can occur. To reduce leakage, a row of guide vanes can be combined via a common shroud to form a guide vane segment, thus reducing the number of gaps. Inserted into the outer casing, the guide vane segment is secured against displacement by means of a hook arrangement.During compressor operation, the guide vane segments are exposed to significant temperature differences between the outer and inner regions of the flow channel. These resulting temperature gradients lead to a bulging of the guide vane segment's shroud during aircraft engine operation. This can, on the one hand, lead to increased contact pressure in some areas of an adjacent casing groove that accommodates the hook assembly, and, on the other hand, can cause the gaps between the casing and the shroud and the hook assembly, as well as the air gaps of the adjacent rotors and the outer casing to widen.

[0003] This cambering effect is particularly problematic with larger segments, as the mechanical deflections between the ends of the shroud due to thermal stresses accumulate and become greater the further the segments extend in the circumferential direction. The cambering of the shroud must therefore be taken into account when designing the gaps. This disadvantageous effect leads to reinforcements, particularly in the area of the guide vane hooks and in the casing groove of the flow channel, and / or to larger gap dimensions when designing the casing gaps, especially in the air gaps of the adjacent rotors.

[0004] It is therefore an object of the invention to provide a guide vane segment that at least partially reduces or avoids the aforementioned disadvantages. It is also an object of the invention to provide an aircraft engine in which the aforementioned disadvantages are at least partially reduced or avoided.

[0005] The object is achieved with a guide vane segment according to claim 1. Furthermore, the object is achieved by an aircraft engine according to claim 13.

[0006] A guide vane segment according to the invention for a flow duct in a compressor of an aircraft engine comprises a series of guide vanes arranged in the circumferential direction and a shroud extending in the circumferential direction. The shroud connects the guide vanes in a blade root region, i.e., in a radially outer region of the guide vanes, in the circumferential direction. In particular, the shroud can form a wall section of an inner wall of an outer casing of the flow duct. The shroud is designed for fastening in the outer casing of the flow duct, wherein the shroud has a hook arrangement extending in the circumferential direction with at least one hook on an outer side of the shroud. The at least one hook can be insertable into a housing groove provided for this purpose in the outer casing.The cover band can be inserted into the housing groove in the circumferential direction and / or can form a positive connection with the housing groove against movement in the radial direction.

[0007] According to a first embodiment, the at least one hook can have at least one recess at a hook end, wherein the recess divides the hook end in the circumferential direction. The at least one recess can divide the hook arrangement into hook sections. The at least one recess advantageously interrupts stresses within the hook in the circumferential direction and reduces the stiffness of the hooks in the circumferential direction, thereby advantageously reducing bowing. Deformations no longer accumulate but rather occur locally in the hook sections extending in the circumferential direction. Advantageously, the number of recesses can be greater than or equal to the number of blades. The at least one recess can extend in particular transversely to a circumferential extent of the hook arrangement.The recess can have an elongated extension, preferably in the axial direction or obliquely to the axial direction, and can, in particular, completely penetrate the hook in the radial direction. The hook end can extend in the axial direction parallel or approximately parallel to an engine axis and, in particular, have a flat surface on its outer side and / or on its inner side that is aligned parallel to the engine axis. A transition region serving as a hook bend can be arranged between the hook end and a hook foot. The hook arrangement can be designed like a rail.

[0008] In this description, an axial direction is defined as running parallel to an engine axis, with a "front" being defined at the engine inlet and a "rear" at the engine exhaust. Directions perpendicular to the engine axis are defined as radial directions. The radial directions run from the inside of the engine axis to the outside. Finally, the circumferential direction is defined as the direction around the engine axis. A radial direction and an axial direction together form the basis of a meridian plane; their section through the engine is defined as a meridian section. Cross-sections formed in a meridian plane and extending in the circumferential direction result in a circumferentially curved body.

[0009] Further advantages and features emerge from the following description of some preferred embodiments and the dependent claims.

[0010] In an advantageous embodiment of the guide vane segment according to the invention, the at least one hook can have several recesses distributed in the circumferential direction at the hook end. The more recesses there are, the less the deflection effect affects each individual hook section and thus the entire hook arrangement.

[0011] In a further advantageous embodiment of the invention, it can be provided that the recesses are evenly distributed in the circumferential direction. By evenly distributing the recesses in the circumferential direction, the individual hook sections can advantageously be designed uniformly, which simplifies production and thus reduces costs. The even distribution can also be limited to just a subsection of the hook arrangement, whereby, for example, larger and / or smaller distances can be provided at the ends between two recesses or between a recess and a cover band end face or an end face of the hook arrangement. When arranged in the circumferential direction, the recesses form a row of recesses. Of the row of recesses, only the inner recesses of the row can be evenly distributed.The row may have an end distance from the circumferential ends of the hook arrangement, wherein the end distance may be different from a distance between two adjacent recesses or all adjacent recesses.

[0012] In a particularly preferred development, it can be provided that the hook is a first hook with a first hook end, and that the hook arrangement has a second hook with a second hook end, and that the second hook has at least one second recess on the second hook end, wherein the at least one second recess divides the second hook end in the circumferential direction. By arranging recesses on both sides in the hook arrangement, the component stresses can be distributed particularly effectively, so that the deflection effect is advantageously reduced even further. It can be provided that the two hook ends of the first hook and the second hook project in the axial direction in opposite directions, in particular from a common platform.A surface of the platform can be arranged radially further outward relative to an edge of a front side of the cover strip and / or relative to an edge of a rear side of the cover strip. The platform can also be referred to as a hook shank. Furthermore, it can be provided that the at least one recess of the first hook and the at least one recess of the second hook extend in opposite directions in the axial direction.

[0013] This means that the recesses divide their respective hook ends and, if appropriate, the corresponding transition region from opposite directions. Particularly preferably, a recess in the first hook and a recess in the second hook can be arranged in a common sectional plane in the circumferential direction, in particular in a common meridian section. The opposite first and second recesses can also be offset from one another, so that a force flow can advantageously alternate through the hooks. The first hook can be a front hook, the second hook can be a rear hook.

[0014] In a preferred supplementary or alternative development of the invention, the at least one recess can extend into an angled transition region of the hook between the hook end and a hook foot. The transition region can be a cantilever extending from the previously described platform, from which the hook end protrudes, in particular in the axial direction. The hook foot is arranged on an upper side of the shroud and forms a connection between the hook arrangement and the remaining shroud, which carries the guide vanes. The transition region can be angled to an engine axis and preferably enclose an angle α of 15° to 45°, in particular 20° to 40°, preferably 25° to 35°, with the engine axis. If the hook arrangement has two hooks, both hooks can each have a transition region. If the hook arrangement has two hooks, the respective transition regions can be arranged in a V-arrangement.The first transition region of the first hook can form an angle α 1 with the engine axis that is different from the angle α 2 formed by the second transition region of the second hook with the engine axis. The two hooks can preferably extend in opposite directions.

[0015] In another particularly advantageous embodiment of the invention, which may be claimed independently, the at least one hook can have an angled transition region between the hook end and a hook foot, and the angled transition region can form an angle of 70°-20°, in particular of 65°-30°, particularly preferably of 35° to 50°, with a platform of the blade on the side facing away from a platform center. This allows for improved manufacturability using additive manufacturing processes.

[0016] In a further development of the invention, at least one hook foot is arranged indented relative to an axial end of the platform, so that, when an intersection is formed between an extension of the leading or trailing edge of the platform's blade, the hook foot is arranged behind this intersection point toward the center of the platform. In other words, the hook foot should be indented relative to a fillet area of the blade in the axial direction relative to an axial end of the platform.

[0017] This has advantages, especially in combination with an angled transition area but also in isolation, as it avoids stress peaks in the cover strip, which prevents cracking.

[0018] In a further preferred embodiment, the hook foot can be indented relative to the axial end of the platform by at least 15%, preferably at least 25%, particularly preferably by at least 30%, further preferably by at least 35%, further preferably by at least 40% of the total length of the platform. In order to measure the indentation of the hook foot relative to the axial platform length, a distance can be taken between an axial end of the platform and an intersection point, wherein the intersection point, viewed in a meridional section, is an intersection point of an axis through the center of the longitudinal extent of the transition region of the hook and the radial platform outer side.

[0019] In a further preferred embodiment, the guide vane segment can have two hooks, wherein there is a radial offset between the two hook ends, in particular an offset by at least the radial thickness of the hook end of one of the two hooks.

[0020] In a particularly preferred development, the recess can have a cross-sectional widening, which is in particular a relief notch, transverse to a longitudinal extent of the recess in an end section facing away from an axial end face of the hook end. The cross-sectional widening can be followed by a cross-sectional tapering in the longitudinal extent. This cross-sectional widening advantageously reduces the notch effect and thus the notch effect in the region of the end face of the hook end.

[0021] The recess can preferably be formed as a narrow slot, with a first end of the slot located on an axial end face of the hook end. The end portion is located opposite the first end of the recess, in particular in the axial direction, in an inner region of the hook, with one end of the recess preferably being arranged in a transition region.

[0022] According to one embodiment, the recess can be filled with a material that is softer than the material of the hook, in particular with a solder or a plastic.

[0023] Particularly preferably, the cross-sectional widening can be a round hole extending in the radial direction, a square hole with rounded corners, and / or a rectangular hole with rounded corners. The cross-sectional widening can extend completely in the radial direction through the hook end or the transition region. A cross-section of the recess in the cross-sectional widening on a surface of the hook can extend completely in the radial direction through the hook. A round hole, in particular a circular or elliptical round hole, a square hole with rounded corners, and a rectangular hole with rounded corners are advantageously particularly well suited as a relief notch.

[0024] Furthermore, the cross-sectional expansion can be arranged in or at a kink and / or bend between the hook end and a transition area of the hook. This allows the notch effect of the recess to be advantageously introduced into the transition area. In particular, it can be provided that the cross-sectional expansion is arranged in equal parts on both sides of the kink or bend, on the one hand, along the longitudinal extension of the recess and in a surface projected in the radial direction, or on the other hand, relative to a distant volume. This distributes the notch effect particularly favorably.

[0025] Alternatively, the cross-sectional widening may be adjacent to a kink and / or a curvature between the hook end and a transition region of the hook or may have a small distance to a kink and / or a curvature between the hook end and a transition region of the hook of less than 5%, in particular 4%, preferably less than 3% of the longitudinal extent of the recess.

[0026] In a particular refinement, it can be provided that the at least one recess is slit-shaped. Due to the slit-shaped design of the recess, only a small portion of the hook is advantageously removed, so that the load-bearing capacity of the hook arrangement is advantageously hardly impaired, while at the same time the deflection effect is reduced. A first end of the slit can be located on an end face of the hook end. The end section is opposite the first end of the recess, in particular in the axial direction, preferably in the longitudinal direction of the recess.

[0027] Alternatively or additionally, the at least one recess can divide the hook in the circumferential direction into at least two hook sections, wherein a transverse extension transverse to a longitudinal extension of the recess can amount to a cross-sectional widening of between 2.5% and 7.5% of a circumferential extension of a circumferential end-side hook section adjacent to the recess. Further alternatively or additionally, a number of recesses distributed in the circumferential direction can divide the hook into a number of hook sections increased by one, wherein a transverse extension of the distributed recesses transverse to a longitudinal extension of the respective recesses can amount to a cross-sectional widening of between 5% and 15% of a circumferential extension of a hook section delimited by two adjacent of the distributed recesses.This also has the advantage that only a small part of the load-bearing hook is removed, so that the load-bearing capacity of the hook arrangement is hardly affected, while at the same time the deflection effect is reduced.

[0028] In a very advantageous development of the guide vane segment, the hook end, in particular also a transition region of the at least one hook adjacent to the hook end, can be surrounded by a friction plate, wherein the friction plate extends at least partially over the at least one recess in the circumferential direction. This advantageously prevents direct friction between the hook and at least reduces leakage flow through the recess. The friction plate can be formed as part of the hook arrangement and fastened to the hook before being inserted into the housing groove. The friction plate can be positively connected to the hook in a meridian section. In particular, the friction plate can have a cross-section in a meridian section that is adapted to a surface of the hook end and / or the transition region for force-fitting contact between the hook and the housing groove.

[0029] In a preferred embodiment, the friction plate can also be mounted across segments, ie in a guide vane arrangement with several adjacently arranged guide vane clusters, the friction plate can cover at least two guide vane clusters and cover the gap at the joint between the two clusters.

[0030] In an advantageous embodiment, the hook can be a first hook and the hook end a first hook end, and the hook arrangement can have a second hook. The second hook can have a second hook end, and the second hook can have at least one recess at the second hook end. Furthermore, the hook end of the first hook can be surrounded by a first friction plate, and the hook end of the second hook can be surrounded by a second friction plate. In particular, it can be provided that the first friction plate and the second friction plate are spaced apart from one another in the axial direction. In addition, the first friction plate and the second friction plate can completely cover the respectively covered recesses in the axial direction and / or in the circumferential direction. This advantageously reduces leakage flow to a minimum.

[0031] In a particularly preferred development, the friction plate, in the case of two friction plates provided, both or at least one of the friction plates, has a thickness between 0.1 mm and 0.5 mm, in particular between 0.2 mm and 0.4 mm, preferably between 0.25 mm and 0.35 mm, particularly preferably 0.3 mm. Such a thickness achieves a particularly favorable compromise between sufficient strength and low weight. In addition, the friction plate can be easily adapted to the shape of the hook, so that a particularly good sealing effect against leakage flow is achieved. If two friction plates are provided, they can have the same thickness. However, it can also be provided that one of the two friction plates is thicker than the other of the two friction plates. The thickness of the friction plates can vary within the specified ranges along a flat extension of the friction plates.It can be provided that the first friction plate completely and / or on both sides covers the respective recesses covered by the first friction plate. It can be provided that the second friction plate completely and / or on both sides covers the respective recesses covered by the first friction plate.

[0032] A further aspect of the invention relates to an aircraft engine with a compressor of a flow duct, wherein the compressor has a guide vane segment, in particular according to one of the preceding claims. The guide vane segment has a row of guide vanes arranged in the circumferential direction and a shroud extending in the circumferential direction. Furthermore, the shroud connects the guide vanes in a blade root region in the circumferential direction, wherein the shroud is fastened in the outer casing of the flow duct. The shroud has a hook arrangement extending in the circumferential direction with at least one hook on an outer side of the shroud, wherein the at least one hook is inserted in a housing groove provided for this purpose in the outer casing and forms a positive connection with the housing groove against movement in the radial direction.The object of the invention is achieved in that the at least one hook has at least one recess at one hook end, wherein the at least one recess divides the hook end along its longitudinal extension in the circumferential direction. This advantageously reduces the deflection effect of the cover band.

[0033] It can be provided that the recess is arranged in the circumferential direction in a sectional plane, in particular in a meridian section, and is offset in the circumferential direction from the blade leading edges of the guide vanes arranged closest to the sectional plane. Alternatively or additionally, it can be provided that the recess is arranged in the circumferential direction in a sectional plane, in particular a meridian section, between two blade leading edges of two adjacent guide vanes of the guide vanes. Alternatively or additionally, the recess can be arranged in the circumferential direction in a sectional plane, in particular a meridian section, between a leading edge and a trailing edge of a guide vane of the guide vanes.

[0034] Furthermore, it can be provided that the shroud has an axial extension on a duct wall section that is larger toward the front and / or rear, in particular at least 10% larger, preferably at least 12% larger, particularly preferably at least 14% larger, in particular at least 16% larger, than an axial distance between a leading edge and a trailing edge of one of the guide vanes. This advantageously allows a surface contouring to be arranged on the surface of the duct wall section in front of and / or behind the guide vanes.

[0035] The invention is explained in more detail with reference to the following drawings using some preferred embodiments of the invention. Fig. 1 shows a schematic representation of an aircraft engine according to the invention with a first embodiment of a guide vane segment according to the invention of a compressor Fig. 2 shows the embodiment of the guide vane segment according to the invention with a friction plate in a perspective representation Fig. 3 shows the embodiment of the guide vane segment according to the invention without the friction plate in a perspective representation Fig. 4 shows a section of a hook end of the embodiment of the guide vane segment according to the invention in a radial plan view Fig. 5 shows the embodiment of the guide vane segment according to the invention in a housing groove of a flow channel of the aircraft engine according to the invention in a meridian section Fig. 6 shows a further embodiment with only one hook with an angled transition region.

[0036] In Fig. 1An aircraft engine 1 is shown schematically in a meridional section. The aircraft engine 1 has an engine inlet 1a, from which downstream flow flows into a bypass duct 1b and a flow duct 1c serving as a core flow duct. Bypass duct 1b serves to generate thrust, while flow duct 1c primarily serves to generate power for the components of the aircraft engine 1 and the cabin systems of an aircraft. In the flow channel 1c, the main components of the aircraft engine 1 are arranged in sequence in the direction of flow, 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, wherein the intermediate casing 7 serves as the outer casing 7 of the flow channel 1c.A fan 5 with one or more fan stages for sucking 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 rotation axis 8a, wherein the fan 5 and optionally also front low-pressure compressor stages (not shown) can be decoupled from the faster-running turbine 4, in particular from a low-pressure turbine, by a gear 9. A portion of the air sucked in and compressed by the fan flows into the flow channel 1c, where it is strongly compressed by the compressor 2 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. The compressor 2 provides compressed bleed air for a bleed air system at bleed air points.

[0037] The engine rotation axis 8a serves as a reference axis for the definition of an axial direction Ax running parallel to the engine rotation axis 8a, a radial direction R perpendicular thereto and a circumferential direction U running around the engine rotation axis 8a.

[0038] Due to the high compression in the compressor 2, the temperature within the flow channel 1c increases, resulting in high temperature gradients in the adjacent channel walls. According to the invention, a guide vane segment 10 according to the invention is arranged in the compressor 2 of the aircraft engine 1, which is Fig. 2 to 5 illustrated embodiment is described in more detail and can better withstand the temperature gradients, so that a curvature effect that usually occurs with such a cover band is at least reduced.

[0039] In Fig. 2The exemplary embodiment of the guide vane segment 10 according to the invention with a friction plate 80 is shown in a perspective view. The guide vane segment 10 can, as shown, have four guide vanes 20, which are connected in a blade root region 21 by a shroud 30 extending in the circumferential direction U. The shroud 30 can, however, also connect more or fewer than four blades, in particular five, preferably six, particularly preferably seven, even more preferably eight, even more preferably nine, even more preferably ten blades 20 in the circumferential direction. The shroud 30 forms, with its radially inner inner side 31, a channel wall section 31 of the flow channel 1c and has, on its radially outer outer side 32, a hook arrangement 40 for fastening in a Fig. 4 described in more detail below, the housing groove 71 of the outer housing 7.

[0040] The hook arrangement 40 can have two hooks 41, 42, a first hook 41 with a first hook end 43 and a second hook 42 with a second hook end 44, wherein the hook ends 43, 44 point in opposite directions in the axial direction Ax. In particular, an inner surface and / or an outer surface of the first hook end and / or of the second hook end can extend parallel to a plane spanned by the axial direction Ax and the circumferential direction U and curved in the circumferential direction U. In the present exemplary embodiment, a cross-section formed by the hooks 41, 42 extends in the circumferential direction U.

[0041] The hooks 41, 42 have, adjacent to the hook ends 43, 44, a transition region 47, 48 which extends from the respective hook end 43, 44 to a first hook foot 49 or a second hook foot 50 of the respective hook 41, 42, wherein the hook arrangement 40 is integrally connected to the remaining cover band 30 by means of the hook feet 49, 50. The transition region 47, 48 runs at an angle to the axial direction Ax. The first transition region 47 forms an angle α 1 with the axial direction Ax. The second transition region 48 forms an angle α 2 with the axial direction Ax. The angle α 1 is 30° in the present exemplary embodiment, but can also be in a range between 20° and 40°, preferably in a range between 25° and 35°. The angle α 2 is 28° in the present embodiment, but can also be in a range between 20° and 40°, preferably in a range between 25° and 35°.For better clarity, the angles α 1 and α 2 are shown in the side view in . Fig. 5 shown.

[0042] The transition areas 47, 48 extend to a respective hook foot 49, 50 of the corresponding hook 41, 42, wherein the hook feet 49, 50 can form a common platform 61 which is raised relative to the remaining outer side 32 of the cover strip and can thus form a region of greater thickness of the cover strip 30.

[0043] As a result, the weight of the blades 20 and the shroud 30 can be advantageously transferred very well to the hooks 41, 42 and thus into the outer casing 7.

[0044] During operation, high temperatures occur in the flow channel 1c compared to the surroundings, so that the shroud 30 bulges due to the temperature gradient occurring therein, which causes it to bend outwards.

[0045] To counteract this, the Fig. 3 to 5described in more detail recesses 45, 46 in the hook ends 43, 44 and a short section in the transition areas 49, 50. Friction plates 80, 81 extend over the recesses and the hooks, which are Fig. 5 shown meridian section through the guide vane segment 10 in the flow channel 7 will be explained in more detail.

[0046] The recesses 45, 46 divide the hook ends 45, 46 and the transition regions 49, 50 into several separate hook sections 57, 58 extending in the circumferential direction U. On the one hand, the stresses in the hook sections 57, 58 are interrupted. On the other hand, the component stresses running in the circumferential direction are thereby directed into the particularly reinforced and stiff hook foot region, so that the deflection is advantageously reduced.

[0047] In the Fig. 3In the embodiment shown, five recesses 45, 46 are arranged distributed in the circumferential direction U, with the hook sections 57, 58 formed between two adjacent recesses being of equal length. Furthermore, one of the first recesses 45 of the first hook 41 is arranged opposite one of the second recesses 46 of the second hook 42 in the axial direction Ax.

[0048] In order to reduce a notch effect of the recesses 45, 46, the recesses 45, 46 can have a cross-sectional widening 55, 56 in an end section 53, 54 facing away from an end face 51, 52 of the respective hook end 43, 44, the transverse extent Q of which initially increases transversely to a longitudinal extent L of the recess 45, 46. The transverse extent can in particular initially increase and then decrease along the longitudinal extent L in the end section 53, 54, and preferably be reduced to zero at one end of the longitudinal extent L. In the present exemplary embodiment, the cross-sectional widening has a circular cross-section viewed in the radial direction R. However, it can also be formed with rounded corners, for example square or rectangular.

[0049] Fig. 4shows an embodiment of a recess 45, 46 in a plan view. The recess 45, 46 can be one of the first recesses 45 or one of the second recesses 46 formed in the hooks 41, 42 in Fig. 3 shown. In the case of a second recess 46, the recess shown would be assumed to be mirrored.

[0050] The longitudinal extent L of the recess 45, 46 extends from an end face 51, 52 of the hook end 43, 44 to an end of an end section 53, 54 of the recess 45, 46 opposite the end face 51, 52. The recess 45, 46 runs in the hook end 43, 44 in a slit-like manner, i.e. with a greater longitudinal extent L than transverse extent Q, until shortly before a curvature 59, 60 in the surface of the hook 41, 42 arranged between the corresponding hook end 43, 44 and the transition region 47, 48. Instead of a curvature 59, 60, a kink can also be formed between the hook end 43, 44 and the transition region 47, 48. The slot-shaped section of the recess 45, 46 is followed in the longitudinal direction L by a cross-sectional widening 55, 56 designed as a relief notch. By means of the cross-sectional widening 55, 56, the increased stress within the hook 41, 42 due to the notch effect of the recess 45, 46 is at least partially advantageously reduced.The cross-sectional expansion has as in . Fig. 3 The cross-section shown is circular. However, it can also have a square or rectangular cross-section with rounded corners, an elliptical shape, or a free-form shape.

[0051] In the embodiment shown, the longitudinal extension L runs parallel to the engine axis 8a and thus to the axial direction Ax. Alternatively, it can be provided that the longitudinal direction L' of the recess 45, 46 - as in the coordinate system on the right in Fig. 4 shown - runs obliquely to the axial direction Ax.

[0052] In Fig. 5 is the Fig. 2 and 3The embodiment shown of the guide vane segment 10 according to the invention is shown with the hook arrangement 40 in a housing groove 72 of an inner wall 71 of the intermediate housing 7. The inner wall 71 of the intermediate housing 7 and the inner side 31 of the shroud 30, designed as a channel wall section 31, together form an outer section of the flow channel 1c.

[0053] In the gap between the hook arrangement 40 and the housing groove 72, a first friction plate 80 is arranged around the first hook 41 and a second friction plate 81 is arranged around the second hook 42. The friction plates 80, 81 each completely surround the corresponding hook end 43, 44 and extend beyond the transition area and cover the respective transition area 47, 48. A respective central sheet metal section 82, 83 of the corresponding friction plate 80, 81 rests on the respective end face of the respective hook end 43, 44 and closes the gap between the corresponding hook 41, 42 and the housing groove 72. A respective outer sheet metal section 84, 85 extends from the hook end 43, 44 beyond the transition area 47, 48, follows the contour of the hook end 43, 44 and the transition area 47, 48 and completely covers the recess 45, 46 on its radial upper side.It can also be provided that the outer sheet section 84, 84 rests on the upper side of the hook 45, 46 completely along its extension in a meridian plane.

[0054] A respective inner sheet section 86, 87 extends from the hook end 43, 44 to below the transition region 47, 48, following the contour of the hook end 43, 44 and the transition region 47, 48, and completely covers the recess 45, 46 and, in particular in the present embodiment, also the cross-sectional widening 55, 56 on its radial underside, while also completely abutting the underside of the hook 41, 42. This has the advantage that the recess is completely closed, thus preventing leakage, while still reducing the deflection effect caused by the recesses 41, 42.

[0055] In Fig. 5It can also be seen that the channel wall section 31 has a front axial projection 33 and a rear axial projection 34 relative to the guide vanes 20. The channel wall section 31 with at least one axial projection 33, 34 has a significantly greater axial extension between a front end face 35 and a rear end face 36 of the channel wall section 31 than the guide vanes 20, which extend from the channel wall section 31 in the radial direction R, between their leading edge 22 and their trailing edge 23 in the blade root region 21. Any fillet that may be produced is also taken into account here. A surface contouring 37, shown in dashed lines, can therefore advantageously be formed on the corresponding at least one axial projection 33, 34 to improve the flow guidance.

[0056] Figure 6shows a further embodiment with only one hook with an angled transition area. The transition area 48 here forms an angle α of 45° with the platform on its side facing away from the platform center. In this example, the hook foot is indented or offset by an indentation 38 of approximately 28% to 35% of the axial extension of the platform 61 relative to the axial end of the platform towards the platform center. This causes force to be introduced behind the fillet, i.e. the transition between the blade and the platform, which avoids stress peaks during operation. In other words, the hook foot is located behind an intersection point 88 between the platform and the extension of the blade edge.The indentation 38 is measured as the distance between an axial end of the platform and an intersection point, wherein the intersection point, viewed in a meridional section, is the intersection point of an axis through the center of the longitudinal extension of the transition region 48 of the hook and the radial outer side of the platform. In this exemplary embodiment, there is also a radial offset R1 between the two hook ends 43, 44, which is greater than the radial thickness of the hook end 44. List of reference symbols

[0057] 1 Aircraft engine 1a Inlet 1b Bypass duct 1c Flow duct / core flow duct 2 Compressor 3 Combustion chamber 4 Turbine 5 Fan 6 Engine outer casing 7 Outer casing of the flow duct / intermediate casing 8 Shaft 8a Engine axis 9 Gearbox 10 Guide vane segment 20 Guide vane 21 Blade root area 22 Leading edge 23 Trailing edge 30 Shroud 31 Channel wall section, inside of the shroud 32 Outside of the shroud 33 Front axial projection 34 Rear axial projection 35 Front end 36 Rear end 37 Surface contouring 38 Indentation 40 Hook arrangement 41 First hook 42 Second hook 43 First hook end 44 Second hook end 45 First recess 46 Second recess 47First transition area 48Second transition area 49First hook foot 50Second hook foot 51First end face (of the first hook) 52Second end face (of the second hook) 53First end section 54Second end section 55First cross-sectional extension 56Second cross-sectional extension 57First hook section (in circumferential direction) 58SecondHook section (in circumferential direction) 59First kink or bend 60Second kink or bend 61Platform 71Inner wall of the intermediate housing 72Housing groove 80First friction plate 81Second friction plate 82First center section 83Second center section 84First plate upper side 85Second plate upper side 86First plate lower side 87Second plate lower side 88Intersection of the blade edge extension and the platform AxAxial direction RRadial direction UCircumferential direction R1Radial offset LLongitudinal extension of a recess QTransverse extension of a recess UECircumferential extension of a hook section

Claims

1. Guide vane segment (10) for a flow channel (1c) in a compressor (2) of an aircraft engine (1), comprising a row of guide vanes (20) arranged in the circumferential direction (U), and a shroud (30) extending in the circumferential direction (U), wherein the shroud (30) connects the guide vanes (20) in a blade root region (21) in the circumferential direction (U), wherein the shroud (30) is designed for fastening in an outer housing (7) of the flow channel (1c), wherein the shroud (30) has a hook arrangement (40) extending in the circumferential direction (U) with at least one hook (41, 42) on an outer side (32) of the shroud (30).

2. Guide vane segment according to claim 1, characterized in that the at least one hook (41, 42) has a plurality of recesses (45, 46) distributed in the circumferential direction (U) at one hook end (43, 44).

3. Guide vane segment according to one of the preceding claims, characterized by thatthe at least one recess (45, 46) extends into an angled transition region (47, 48) of the hook (41, 42) between the hook end and a hook foot (49, 50).

4. Guide vane segment according to one of claims 6 or 7, characterized by that the cross-sectional widening (55, 56) is arranged in or at a kink (59, 60) and / or a bend (59, 60) between the hook end (43, 44) and a transition region of the hook.

5. Guide vane segment according to one of the preceding claims, characterized by that the hook end (43, 44) of the at least one hook (41, 42) is surrounded by a friction plate (80, 81), wherein the friction plate (80, 81) extends in the circumferential direction (U) at least in sections over the at least one recess (45, 46).

6. Guide vane segment according to one of the preceding claims, characterized by thatthe hook (41, 42) is a first hook (41) with a first hook end (43), and that the hook arrangement (40) has a second hook (42) with a second hook end (44), wherein the second hook (42) has at least one recess (46) at the second hook end (44), and that the first hook end (43) of the first hook (41) is surrounded by a first friction plate (80), and that the second hook end (44) of the second hook (42) is surrounded by a second friction plate (81).

7. Guide vane segment according to one of claims 10 or 11, characterized by that the friction plate (80, 81), in particular both friction plates (80, 81), has a thickness between 0.1 mm and 0.5 mm, in particular between 0.2 mm and 0.4 mm, preferably between 0.25 mm and 0.35 mm, particularly preferably 0.3 mm.

8. Guide vane segment according to one of the preceding claims, characterized by thatthe shroud (30) has an axial extension on a channel wall section (31) which is larger towards the front and / or rear in the axial direction, in particular at least 10% larger, preferably at least 12% larger, particularly preferably at least 14% larger, in particular at least 16% larger, than an axial distance between a leading edge (22) and a trailing edge (23) of one of the guide vanes (20).

9. Guide vane segment according to one of the preceding claims, characterized in that the hook (41, 42) has an angled transition region (47, 48) between the hook end and a hook foot (49, 50) and that the angled transition region encloses an angle of 70°-20°, in particular of 65°-30°, with a platform (61) of the blade on the side facing away from a platform center.

10. Guide vane segment according to one of the preceding claims, characterized by thatthe hook foot (49, 50) is arranged indented relative to an axial end of the platform (61) so that when an intersection point (88) is formed between an extension of the front or rear edge (22, 23) of the blade of the platform (61), the hook foot (49, 50) is arranged behind this intersection point (88) in the direction of the center of the platform (61).

11. Guide vane segment according to claim 10, characterized by that the hook foot (49, 50) is indented relative to the axial end of the platform by at least 15%, preferably at least 25%, particularly preferably by at least 35% of the total length of the platform (61).

12. Guide vane segment according to one of the preceding claims, characterized by thatthe hook (41, 42) is a first hook (41) with a first hook end (43), and that the hook arrangement (40) has a second hook (42) with a second hook end (44), wherein there is a radial offset (R1) between the two hook ends (43, 44), in particular an offset (R1) of at least the radial thickness of the second hook end (44).

13. An aircraft engine (1) with a compressor (2) of a flow duct (1c), wherein the compressor (2) has a guide vane segment (10), in particular according to one of the preceding claims, wherein the guide vane segment (10) has a row of guide vanes (20) arranged in the circumferential direction, and wherein the guide vane segment (10) has a shroud (30) extending in the circumferential direction (U), wherein the shroud (30) connects the guide vanes (20) in a blade root region (21) in the circumferential direction (U), wherein the shroud (30) is fastened in the outer casing (7) of the flow duct (1c), wherein the shroud (30) has a hook arrangement (40) extending in the circumferential direction (U) with at least one hook (41, 42) on an outer side (32) of the shroud (30), wherein the at least one hook (41) is arranged in a provided housing groove (62) in the outer housing (60),and forms a positive connection with the housing groove (62) against movement in the radial direction (R).

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