Blade for a turbine or a compressor

Abstract

The invention relates to a blade (1) for a turbine or a compressor, having an inner core (2) and an outer shell (3) which partly surrounds the core (2) The core (2) has at least one feed channel (4) for cooling fluid and passage channels (5) which connect the feed channel (4) to an inner cooling chamber (8) formed between the exterior (6) of the core (2) and the interior (7) of the outer shell (3). In order to advantageously further develop the blade (1), the inner cooling chamber (8) has a flow connection to an outlet (10) formed by the core (2) in the region of the trailing edge (9) of the blade (1).

Description

[0001] REHBERG HÜPPE + PARTNER - 1 - Originally submitted version 22023PCT 10.11.2025

[0002] RHP Ref.: 22023PCT ZDP3

[0003] Patent application: File number not yet assigned

[0004] Priority: 12.11.2024 (DE 102024133082.1)

[0005] Title: Blade for a turbine or compressor

[0006] Applicant: German Aerospace Center (DLR)

[0007] SHELL FOR A TURBINE OR COMPRESSOR

[0008] TECHNICAL AREA OF INVENTION

[0009] The invention relates to a blade for a turbine or compressor. The blade has an inner core with at least one supply channel for cooling fluid and an outer shell partially surrounding the core. The core has through-channels that connect the supply channel to an inner cooling chamber formed between an outer surface of the core and an inner surface of the outer shell. The inner cooling chamber has a flow connection to an outlet formed by the core in the region of the trailing edge of the blade. The outer shell is pre-formed into a U-profile with two opposing side legs.

[0010] STATE OF THE ART

[0011] EP 1 429 917 B1 discloses a turbine blade with a core made of a ceramic fiber composite, in which a central longitudinal channel for the flow of cooling fluid runs along the length of the blade. The core is provided with a ceramic coating on the outside. Cooling channels run through the ceramic fiber composite of the core and are connected to the central longitudinal channel via bores. The cooling fluid flows from the central longitudinal channel through the cooling channels of the ceramic fiber composite and then outwards into the environment via an outlet opening at a trailing edge of the blade.

[0012] EP 2039884 B1 discloses a turbine blade with an inner metallic core and a ceramic shell surrounding the core. The core and shell are arranged at the end face of the blade, with respect to its longitudinal direction, between two covers and spaced apart from each other such that the core and shell do not touch and form a cooling channel between them. The cooling channel, as well as a separate central feed channel, REHBERG HÜPPE + PARTNER - 2 - Originally filed version 22023PCT 10.11.2025

[0013] The turbine blades, which are formed within the core, are fed via a frontal cover.

[0014] EP 3342980 B1 discloses a turbine blade with a metallic core covered on its leading edge with an outer ceramic wear layer. The metallic core has an internal flow channel running longitudinally along the blade. Through bores in the metallic core, cooling fluid can enter from the internal flow channel into a space between the metallic core and the ceramic wear layer. From there, the cooling fluid exits the turbine blade through outlet openings in the ceramic wear layer.

[0015] EP 2659095 B1 discloses a turbine blade with a core and a casing plate configured to at least partially enclose the core. A flow channel is formed between the casing plate and the core, connecting a cooling air supply chamber formed in the core with outlets on the rear side of the turbine blade. The casing plate is positively or materially bonded to the core.

[0016] US 2017 / 0254206 A1 discloses a turbine blade with a core and an outer shell. The outer shell is supported on the core by webs and engages in undercuts of the core to secure the outer shell to the core.

[0017] TASK OF INVENTION

[0018] The invention is based on the objective of improving a turbine blade with regard to thermal stresses, structural design, assembly, acting stresses and / or flow around it.

[0019] SOLUTION

[0020] The problem of the invention is solved by the features of the independent claims. Further embodiments can be found in the dependent claims. REHBERG HÜPPE + PARTNER - 3 - Originally filed version 22023PCT 10.11.2025

[0021] DESCRIPTION OF THE INVENTION

[0022] The invention relates to a blade for a turbine or compressor. The blade has an inner core with at least one supply channel for cooling fluid and an outer shell that partially surrounds the core. In particular, the outer shell at least partially surrounds the core with respect to the maximum profile depth of the blade measured from a leading edge exposed to the flow to a trailing edge. The core further has through-channels that connect the at least one supply channel to an inner cooling chamber formed between an outer surface of the core and an inner surface of the outer shell. The inner cooling chamber has a flow connection to an outlet formed by the core in the region of the trailing edge of the blade. Furthermore, the outer shell is pre-formed into a U-profile, which has two opposing side legs.

[0023] According to the invention, the side legs are pre-formed in such a way that at room temperature a force is applied to the outer shell via a connecting element which is guided through the core in the area of ​​the trailing edge of the blade.

[0024] According to one embodiment, free ends of the outer shell can first be arranged spaced apart from the core and then attached to and / or held against the core by means of the connecting element, for example a screw or similar.

[0025] In particular, the core has one or more internal supply channels for cooling fluid extending along a longitudinal axis of the blade that runs transversely to the profile depth and thickness. The supply channel(s) is preferably fed from the end face via a connection to the turbine or compressor. Furthermore, the core of the blade incorporates through-channels that connect the supply channel(s) to an internal cooling chamber formed between an outer surface of the core and an inner surface of the outer shell. Cooling fluid can flow from the supply channel(s) of the core into the internal cooling chamber through these through-channels.

[0026] The outlet can preferably be designed in the region of the trailing edge of the blade such that it opens directly into the trailing edge. Alternatively, the outlet can be located at a certain distance from the trailing edge, in particular from a rear corner of the trailing edge, which corner is the end of the blade opposite the leading edge of the blade exposed to the flow. REHBERG HÜPPE + PARTNER - 4 - Originally submitted version 22023PCT 10.11.2025

[0027] The distance between the edge of the outlet opening facing the corner and the corner itself is preferably less than 25% of the maximum slat depth of the blade, more preferably less than 20%, 15%, 10%, or 5% of the maximum slat depth. Intermediate values ​​of these percentages are also possible.

[0028] The design according to the invention allows for the avoidance or reduction of bores or holes in the outer shell around which mechanical stress peaks can occur due to stress concentration during blade operation. Furthermore, the cooling fluid is guided within the inner cooling chamber both along the outside of the core and along the inside of the outer shell, thus cooling the blade.

[0029] After absorbing heat from the core and / or outer shell, the cooling fluid preferably exits the blade exclusively at the trailing edge. Thus, the cooling fluid does not escape into the environment at the leading edge of the blade, but is preferably guided over a significant portion of the blade's maximum profile depth to the rear outlet. However, it is not excluded that the leading edge of the blade and / or one or both sides of the blade also have outlets for cooling fluid. Therefore, in addition to the outlet at the trailing edge, the blade can have one or more further outlets positioned at a distance from the trailing edge. The arrangement and design of the additional outlet(s) can be selected depending on the desired influence on the flow conditions.However, it is preferred that the majority of the cooling fluid leaves the blade only in the area of ​​the trailing edge of the blade.

[0030] By routing the internal cooling chamber back into the core in the area of ​​the trailing edge of the blade, namely into the outlet formed by the core, structural integrity and optimization of the cooling air flow are achieved, which ultimately leads to an increase in the efficiency of the cooling.

[0031] In the blade designed according to the invention, the cooling fluid first flows into the supply channel, for example via an end-face cover of the blade. Through the core's through-channels, the cooling fluid can pass from the supply channel into the inner cooling chamber between the core and the outer shell, where the cooling fluid comes into contact with the outer shell of the blade from the inside. REHBERG HÜPPE + PARTNER - 5 - Originally filed version 22023PCT 10.11.2025

[0032] This can cause impact cooling. Subsequently, the cooling fluid flows with a further cooling effect along the outside of the core and along the inside of the outer shell through the inner cooling chamber to the outlets in the area of ​​the trailing edge of the blade and possibly to one or more outlets that are not located in the area of ​​the trailing edge of the blade.

[0033] The inner cooling chamber can incorporate webs that support the inner surface of the outer shell against the core. These webs separate the outer shell from the opposing inner wall of the cooling chamber, which is formed by the core, thus creating a free volume for the flow of cooling fluid. The webs can be homogeneously distributed at equal intervals within the cooling chamber or—depending on the mechanical, geometric, and / or fluid dynamic properties of the blade—have varying spacings. This allows for greater mechanical stability of the outer shell in areas with particularly curved blade contours, such as the leading edge, or for more precise control of the contour shape. The webs can have different diameters, lengths, and / or cross-sectional shapes.Furthermore, the surface density of the webs on the core can vary locally, resulting in different numbers of webs per unit area in different parts of the core. Additionally, the webs can have different three-dimensional shapes, for example, as ribs or columns, with diameters that increase or decrease along their length, or with other forms. According to one embodiment, rib-shaped webs can extend within the inner cooling chamber in such a way as to guide the flow within the chamber, for example, in the direction of the blade's chord.

[0034] The webs can be formed from the core. For example, the webs can be an integral part of the core, preferably formed integrally with it. This simplifies the manufacturing of the blade. In particular, the core can be manufactured using a selective laser melting (SLM) process to achieve the one-piece formation of the core and webs. The temperature distribution during operation of the blade in the airflow ensures that the outer shell adheres to the support points formed by the webs. Mechanical contact between the outer shell, the webs, and the core ensures additional cooling of the outer shell through heat conduction into the core. REHBERG HÜPPE + PARTNER - 6 - Originally submitted version 22023PCT 10.11.2025

[0035] Preferably, the outer shell is detachably supported at the end faces of the webs. This simplifies both the manufacturing of the blade and the connection of the outer shell to the webs. Furthermore, the loose connection allows at least minimal movement of the outer shell relative to the webs or the core, thereby reducing mechanical stresses within the blade. The temperature difference between the outside and inside of the blade allows the outer shell to be pressed against the end faces of the webs.

[0036] The outer shell can be made of an elastic, resilient material and / or be pre-formed in such a way that a restoring force (contact force) of the outer shell presses it against the core under operating conditions, and this force can be dimensioned by the pre-forming. The elastic contact force of the outer shell thus acts towards the core and / or towards the end faces of the webs, so that the outer shell rests firmly against the core's support points, particularly the webs. Additionally or alternatively, the outer shell can be pre-formed in such a way that, prior to connection with the core, it is first necessary to elastically deform or expand the outer shell. Subsequently, once the deformation or expansion force is removed, the outer shell presses itself against the core's support points under operating conditions, following the restoring force.

[0037] It is also possible that the outer shell material is anisotropic, meaning that it undergoes a change in shape even with homogeneous heating and curvature. This change in shape can involve the outer shell being pressed more firmly against the core's support points as the temperature increases. This effect can occur along the longitudinal axis of the blade, as well as along the chord or thickness of the airfoil. Even with an isotropic material, a temperature gradient exists between a cooler inner surface and a warmer outer surface of the outer shell, particularly in the area of ​​the blade's leading edge and / or along the circumference of the outer shell. The change in the outer shell's shape caused by this temperature gradient can be used to influence the contact pressure of the outer shell.

[0038] The cool inner surface and the warm outer surface of the outer shell, particularly in the area of ​​the blade's leading edge, and the suppressed thermal deformations, can lead to tensile stresses on the inner surface and compressive stresses on the outer surface when the outer surface heats up. REHBERG HÜPPE + PARTNER - 7 - Originally submitted version 22023PCT 10.11.2025

[0039] The outer shell can therefore be designed, for example, such that after being applied to the core, it is elastically deformed to create a tensile stress on its outer surface. Heating the blade, as manufactured or assembled in this way, can then reduce and / or eliminate this tensile stress on the outer surface, thus improving the mechanical strength of the outer shell during operation. The opposite occurs on the inner surface. The tensile stress on the inner surface, which would normally arise from external heating, can be reduced and / or eliminated by elastic deformation.

[0040] The outer shell can have a U-profile, which is mounted to the core with elastic expansion of the side legs, and / or a profile that is twisted along the longitudinal extent of the blade. For example, the outer shell is shaped such that the ends of the side legs of the U-shape are initially spaced apart from the core during blade assembly and are only pressed against the core by a fastening element. In particular, the effect of temperature leads to an advantageous reduction in mechanical stresses due to the temperature gradient during blade operation.

[0041] The outer shell is preferably prefabricated as a semi-finished product with a U-shape, which may additionally be twisted and / or have a desired geometry in the direction of its longitudinal extent. Alternatively or additionally, the core may be twisted. The outer shell is then preferably slid onto the core in the direction of the blade's longitudinal extent. It is possible that the contour of the outer shell is bent open, further twisted and / or unwound, or otherwise elastically deformed for the assembly process, whereby, when the deforming forces are removed, the elastic restoring forces of the outer shell material during operation can cause the outer shell to spring back and be pressed into place.If, in the reset state of the outer shell, a twisting of the outer shell or a different geometry is desired, a prior elastic deformation may be necessary for sliding the outer shell onto the core, which is then reduced or removed after the final position of the outer shell has been reached.

[0042] Preferably, the outer shell and / or the inner cooling chamber covers the core in the direction of a blade profile depth over at least 30% of the maximum profile depth up to a maximum of 95% of the REHBERG HÜPPE + PARTNER - 8 - Originally submitted version 22023PCT 10.11.2025

[0043] Maximum tread depth. In particular, the outer shell and / or the inner cooling chamber covers as much of the blade's length as possible in the direction of the tread depth to create a large or nearly complete enclosure and / or internal cooling system. Preferably, the blade is thus cooled not only at the leading edge but well beyond. This is achieved when the inner cooling chamber covers the outer shell by at least 30%, 35%, 40%, 45%, 50%, 60%, or 70% up to at least 95% of the maximum tread depth. Intermediate values ​​of the aforementioned percentages are, of course, also possible. In the area of ​​the trailing edge, the outer shell and / or the inner cooling chamber is preferably omitted or not present, with the core forming the outlet in the omitted area, allowing the cooling fluid to escape from the inner cooling chamber to the environment.The length of the recess in the direction of the profile depth can preferably be at least 5% up to 70% of the maximum profile depth. For example, the length of the recess can be at least 30%, 40%, 50%, 55%, 60%, or 65% of the maximum profile depth, with intermediate values ​​for the length of the recess also being possible within these ranges. The recess can have holes and / or bores.

[0044] It is possible that the outer shell extends to different lengths along the chord line on opposite sides of the blade (relative to a blade cross-section). For example, the outer shell and / or the inner cooling chamber may be longer on a pressure side of the blade than on a suction side. Furthermore, the linear expansion of the outer shell does not necessarily correspond to the linear expansion of the inner cooling chamber. In particular, the inner cooling chamber may have a smaller linear expansion than the outer shell.

[0045] In particular, it is proposed that the outer shell and / or the inner cooling chamber cover the core at least up to a point corresponding to the maximum blade profile thickness. In this area, the temperature gradient on the blade and the associated mechanical stresses can be greatest. Extending the inner cooling chamber to the point corresponding to the maximum blade profile thickness already provides good cooling. Furthermore, the overlap beyond the maximum profile thickness also results in mechanical securing, in particular a locking mechanism for the outer shell to the core and / or to structures penetrating the inner cooling chamber, such as the webs. REHBERG HÜPPE + PARTNER - 9 - Originally submitted version 22023PCT 10.11.2025

[0046] One embodiment of the invention provides that the outer shell comprises or consists of a ceramic material and / or a fiber-reinforced ceramic material and / or SiC fibers embedded in a SiC matrix. The outer shell thus exhibits a particularly temperature-stable material. This design can, for example, increase the inlet temperature to a turbine, thereby increasing the turbine's efficiency. Furthermore, a ceramic, and in particular a fiber-reinforced ceramic, outer shell can reduce the weight of the blade compared to a metallic blade.

[0047] In particular, a hybrid design of the blade using different materials for the core and outer shell is possible. This takes into account the material-specific properties of the core and outer shell materials, which can significantly enhance the blade's cooling effect and stability. Specifically, the aerodynamic surfaces of the outer shell can be made of a ceramic material, while the core, for example, is made of a metal.

[0048] Preferably, the outer shell also has no passage channels for the exit of the cooling fluid and no internal flow channels for the cooling fluid, so that an outer shell formed from ceramic material does not lead to stress concentrations within the blade.

[0049] A SiC fiber embedded in a SiC matrix is ​​preferably used as the ceramic material. The ceramic outer shell can advantageously be a prefabricated semi-finished product, which is particularly designed with a constant thickness and defined curvature. The incorporation of cooling holes is generally possible, but not preferred and not necessary in the blade design according to the invention.

[0050] A particular challenge in manufacturing an outer shell from ceramic material is the trailing edge of the blade, where the ceramic fibers converge. Typically, these converging fibers can be joined to form a gusset or stitched together. However, since the trailing edge and the outlet are formed solely by the core and not by the outer shell, a very sharp trailing edge can be created by the core without such complex manufacturing techniques, thus eliminating any negative impact on the outflow at the trailing edge. REHBERG HÜPPE + PARTNER - 10 - Originally submitted version 22023PCT 10.11.2025

[0051] The core of the blade is preferably made of metal. In particular, the core can be formed using a laser melting process to achieve a highly precise three-dimensional shape. Specifically, core webs can be formed integrally with the core. The metal of the core allows for great freedom in three-dimensional design, especially the incorporation of through-channels into the core to facilitate flow from the feed channel into the internal cooling chamber.

[0052] Furthermore, it is possible that the core's passage channels and / or their openings have different sizes and / or spacings. Thus, the passage channels and / or their openings, through which the inner cooling chamber is connected to the core's feed channel, have different diameters and / or densities. In particular, the number of openings per unit area in a first sub-section of the core can differ from the number of openings per unit area in a second sub-section of the core. This allows the cooling capacity to be specifically controlled. Moreover, the openings of the passage channels can also have any identical or different cross-sectional shapes, e.g., elongated, round, square, triangular, or otherwise shaped. Preferably, the proportion of the total opening area (i.e.,The total area of ​​the openings (the sum of all openings of the passage channels at the interface between the core and the inner cooling chamber) must be at least 0.5%, 1%, or 2% of the core's total surface area. Larger proportions of the opening area to the total surface area are also possible.

[0053] The outer shell can be bonded to the core in a material-bonded and / or form-bonded manner.

[0054] According to one possible embodiment, the core can have an undercut into which an end region of the outer shell, pointing towards the trailing edge of the blade, engages in a form-fitting manner. This embodiment is particularly advantageous from a manufacturing perspective, since, for example, a pre-fabricated U-shaped outer shell can be slid onto the core along the longitudinal axis of the blade and engage in a recess, particularly an undercut, of the core. The end regions of the outer shell pointing towards the undercut are preferably shaped to correspond to the recess or undercut of the core, so that, when the core and outer shell are connected, the outer surfaces of the core and outer shell are flush. This prevents aerodynamic disturbances in the transition area between the core and the outer shell.Disassembly of core and outer shell REHBERG HÜPPE + PARTNER - 11 - Originally submitted version 22023PCT 10.11.2025.

[0055] This may then require a widening of the end areas of the outer shell and / or a shift of the outer shell in a longitudinal direction opposite to the assembly direction.

[0056] The outlet at the trailing edge of the blade can have multiple outlet openings formed in the core, arranged sequentially along the blade's length. Alternatively, the outlet can be formed by a single opening, particularly one extending longitudinally along the blade. The size, shape, spacing, and / or number of outlet openings can be used to specifically influence the flow conditions and the mechanical stability of the blade itself. The outlet openings can have any desired geometry. In particular, the geometry can be adapted to minimize any influence on the flow around the blade.

[0057] According to one embodiment, the inner surface of the outer shell can have a texture and / or ribs. The texture and / or ribs improve heat transfer from the outer shell to the cooling airflow or the core. Preferably, the texture and / or ribs are omitted in the area of ​​contact points between the outer shell and the core, for example, with core webs. Thus, no texture or ribs are present in the contact area of ​​the core, particularly the webs, with the outer shell. The inner surface of the outer shell may, under certain circumstances, have an inherent texture, for example, if the outer shell contains ceramic fibers. In contrast, the outer surface preferably has no texture and no ribs in order to maintain optimal flow conditions on the outer side of the blade.

[0058] One embodiment provides that the core of the blade, with respect to a cross-section transverse to the longitudinal extent of the blade, is teardrop-shaped and, abstractly speaking, has a triangular shape with two continuously merging long sides and one short side, wherein a corner of the triangular cross-section forms the pointed trailing edge of the blade, wherein a region of the core, defining the outer shell and the inner cooling chamber, extends from the side of the triangular cross-section opposite the corner to the trailing edge, and wherein an outer surface of the outer shell transitions flush into two sides of the triangular cross-section adjacent to the corner. This flush transition of the outer shell into the sides of the triangular cross-section of the core results in aerodynamically favorable REHBERG HÜPPE + PARTNER - 12 - Originally submitted version 22023PCT 10.11.2025

[0059] Conditions on the outer surface of the blade. Furthermore, this also offers manufacturing advantages, for example, in the form-fitting engagement of the outer shell with undercuts in the core. In particular, this allows for a form-fitting connection both in the direction of the profile thickness and in the direction of the profile depth of the blade.

[0060] In addition to the blade described above, the invention further proposes a compressor or turbine with a blading arrangement consisting of a plurality of guide vanes and / or rotor blades, wherein at least one guide vane and / or rotor blade is designed as a blade of the aforementioned type. The features and advantages of the blade according to the invention described above also apply accordingly to a compressor or turbine that has at least one such blade. To avoid repetition, reference is made to the preceding description.

[0061] When designing a compressor or turbine, it is usually assumed that a guide vane array is subject to constant boundary conditions around its circumference, in particular constant flow velocities and temperatures. In practice, however, the temperature distribution at the inlet of the guide vane array is variable in the circumferential and / or radial direction of the turbine, especially due to an upstream combustion chamber. In the region of temperature peaks, this can lead to defects, failure, or burn-off of the vanes. Accordingly, targeted adaptation of the vanes to the different thermal stresses can be advantageous. In particular, differently shaped vanes can be used within the same guide vane array.For example, in areas with high temperature peaks (also known as "hot streaks"), film cooling can be used more extensively, while in areas with low or no temperature peaks (also known as "cold streaks"), blades according to the invention are used. According to a further embodiment, blades without the use of ceramic material can be used in areas with high temperature peaks, and these blades can then be made of metal and with film cooling.

[0062] Finally, the invention proposes a method for manufacturing a shovel according to the invention, wherein the outer shell is formed in a U-shape from a starting material before being connected to the core, and the pre-formed U-shaped outer shell is then REHBERG HÜPPE + PARTNER - 13 - Originally filed version 22023PCT 10.11.2025

[0063] The outer shell is pushed onto the core in the direction of the blade's longitudinal extent. This can occur with elastic expansion and / or twisting or unwinding. Preferably, during the pushing-on process, a positive fit is also achieved between at least one end region of the outer shell and an undercut of the core, whereby a sliding relative movement of the contact surface between the end region of the outer shell and the undercut of the core in the direction of the blade's longitudinal extent can occur.

[0064] The features and advantages of the shovel according to the invention, described above, in particular the manufacturing process steps, also apply analogously to a method for manufacturing such a shovel. To avoid repetition, reference is therefore made to the preceding description.

[0065] Advantageous further developments of the invention result from the patent claims, the description and the drawings.

[0066] The advantages of features and combinations of features mentioned in the description are merely exemplary and can have an effect alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0067] Regarding the disclosure content—not the scope of protection—of the original application documents and the patent, the following applies: Further features can be derived from the drawings—in particular, the geometries depicted and the relative dimensions of several components to one another, as well as their relative arrangement and functional connection. The combination of features from different embodiments of the invention or from features of different claims is also possible, deviating from the chosen cross-references of the claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features from different claims.Similarly, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent. REHBERG HÜPPE + PARTNER - 14 - Originally filed version 22023PCT 10.11.2025.

[0068] The features mentioned in the claims and the description are to be understood, with regard to their number, as meaning that exactly that number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least". Thus, for example, if a passage channel is mentioned, this is to be understood as meaning that exactly one passage channel, two passage channels, or more passage channels are present. The features listed in the claims may be supplemented by further features or may be the only features that the subject matter of the respective claim possesses.

[0069] The reference numerals contained in the patent claims do not constitute a limitation of the scope of the subject matter protected by the patent claims. They serve only the purpose of making the patent claims easier to understand.

[0070] BRIEF DESCRIPTION OF THE FIGURES

[0071] The invention will now be further explained and described with reference to exemplary embodiments shown in the figures.

[0072] Fig. 1 shows a three-dimensional partially sectioned cross-section through a shovel according to the invention.

[0073] Fig. 2 shows an embodiment of a trailing edge of a shovel.

[0074] FIGURE DESCRIPTION

[0075] Fig. 1 shows a possible embodiment of a blade 1 according to the invention for a turbine or a compressor. The blade 1 is shown in a three-dimensional cross-section.

[0076] The blade 1 has a core 2 and an outer shell 3 that partially surrounds the core 2. The core 2 is made of a metal, for example, using a SLM process (selective laser melting). The outer shell 3 is made of a fiber-reinforced ceramic material, which, for example, comprises SiC fibers in a SiC matrix. REHBERG HÜPPE + PARTNER - 15 - Originally submitted version 22023PCT 10.11.2025

[0077] The core 2 of the blade 1, with respect to the cross-section according to Fig. 1, is essentially teardrop-shaped and, abstractly considered, has a triangular shape with two continuously intersecting long sides 22, 23 and one short side 21, wherein a corner 20 of the triangular cross-section is part of a pointed trailing edge 9 of the blade 1.

[0078] The blade 1 is typically connected to a component of the compressor or turbine at an end face (not shown). The blade 1 can be a guide vane or a rotor blade of the compressor or turbine. Several blades 1 of this design can be provided within the compressor or turbine, or they can alternate within a guide vane assembly with blades that are not designed according to the invention.

[0079] The blade 1 shown here has a profile depth 16 transverse to its longitudinal extent 15. The blade 1 is curved in the direction of the profile depth 16, with the profile thickness 17 oriented transversely to the profile depth 16 exhibiting a thickness distribution with varying values.

[0080] The core 2 is essentially designed as a hollow structure, with a free volume extending primarily in the direction of the longitudinal extension 15 of the blade 1 forming a supply channel 4 for cooling fluid. The supply channel 4 is fed via corresponding components of the compressor or turbine. As an alternative to the embodiment shown here with only one supply channel 4, the core can have several supply channels 4.

[0081] The core 2 has a plurality of passage channels 5 along its circumference through which cooling fluid can flow from the supply channel 4 into an inner cooling chamber 8, which is formed between and bounded by an outer surface 6 of the core 2 and an inner surface 7 of the outer shell 3. The inner cooling chamber 8 can be configured as a single inner cooling chamber 8 or comprise several partial inner cooling chambers 8 that are interconnected by fluid.

[0082] To form the inner cooling space 8 between the outer surface 6 of the core 2 and the inner surface 7 of the outer shell 3, webs 11 are provided, via which the inner surface 7 of the outer shell 3 is supported at support points of the core 2. The webs 11 can be integral components of the core 2 and can be formed during the manufacture of the core 2. The number and / or size and / or shape as well as the distribution of the webs 11 within the inner cooling space 8 can be varied. REHBERG HÜPPE + PARTNER - 16 - Originally submitted version 22023PCT 10.11.2025

[0083] The design is based on the geometry of the blade 1 and / or the mechanical properties of the blade 1. Likewise, the passage channels 5 between the feed channel 4 and the internal cooling chamber 8 can have different sizes, geometries and / or densities, i.e., different distances between them.

[0084] The internal cooling chamber 8 is connected to an outlet 10 in the region of the trailing edge 9 of the blade 1. The outlet 10 is formed by the core 2 and has a plurality of outlet openings 19, which are arranged one behind the other in the direction of the longitudinal extent 15 of the blade 1. The number and / or shape and / or size and / or arrangement of the outlet openings 19 depends on the desired flow conditions at the blade 1.

[0085] The outer shell 3 is pre-formed into a U-profile 13, the U-profile 13 having two opposing side legs 14. These side legs are pre-formed such that, at room temperature, a force is applied to the fiber-reinforced ceramic material via a connecting element 18 to press the outer shell 3 against the end faces 12 of the webs 11 of the core 2. To mount the outer shell 3 to the core 2, the side legs 14 of the U-profile 13 are, for example, moved apart against the restoring force and slid over the core 2 in the direction of the longitudinal extension 15. In the final position reached, the side legs 14 can then be connected to the core 2 by means of the connecting element 18 or a plurality of connecting elements 18, as shown in the figure. The connecting element 18 is, for example, a rivet that passes through the core 2 in the region of the trailing edge 9 of the blade 1.

[0086] Although not shown in the figure, the outer shell 3 can alternatively or additionally have a contour twisted around the orientation of the longitudinal extent 15. According to such an embodiment, the contour of the outer shell 3 can also be bent, twisted, or unwound and thereby elastically deformed, whereby the elastic restoring forces of the material of the outer shell 3 cause the outer shell 3 to press against the core 2 in the desired shape at operating temperatures. In particular, if the outer shell 3 or the blade 1 is twisted, elastic deformation may be necessary during the sliding process, which is minimal again upon reaching the final position or is specifically used to ensure the contact pressure under operating conditions at appropriate operating temperatures. REHBERG HÜPPE + PARTNER - 17 - Originally submitted version 22023PCT 10.11.2025

[0087] In the area of ​​the trailing edge 9 of the blade 1, the free end areas of the side legs 14 of the u-shaped outer shell 3 are inserted into shape-corresponding recesses or undercuts on the outside 24 of the outer shell 3.

[0088] An alternative embodiment of a connection between the outer shell 3 and the core 2 is shown in Fig. 2. This figure depicts a region of the trailing edge 9 of a blade 1. The core 2 has undercuts 25 into which the end regions 26 of the outer shell 3, pointing towards the outlet 10, are inserted. The outer shell 3 is thus secured both in the direction of the profile depth 16 and in the direction of the profile thickness 17 of the blade 1.

[0089] Furthermore, conventional joining techniques such as material-bonded connections can also be used between the outer shell 3 and the core 2.

[0090] The inner surface 7 of the outer shell 3 can furthermore have a texture or ribbing, not shown in detail in the figures, which provides an additional cooling effect by increasing the surface area of ​​the outer shell 3. Preferably, the texture and / or the ribs are recessed in the area of ​​the contact points with the webs 11 to ensure full-surface contact between the outer shell 3 and the webs 11.

[0091] The cooling performance of the blade 1 can be influenced by the size and geometry of the inner cooling chamber 8 and / or the number and / or size and / or shape and / or spacing and / or density of the webs 11 (number of webs per unit area) and / or the number and / or size and / or shape and / or spacing and / or density of the openings of the core's passage channels (number of openings per unit area), as well as, if applicable, a texture or ribbing of the inner surface 7 of the outer shell 3. Cooling occurs on the one hand through the cooling airflow along the inner surface 7 of the outer shell 3 (within the inner cooling chamber 8), and on the other hand additionally via the webs 11 of the core 2, whose end faces 12 are in contact with the inner surface 7 of the outer shell 3, as well as heat conduction via the mechanical contact between the outer shell, the webs, and / or the core.

[0092] The outer shell 3 and / or the inner cooling chamber 8 can overlap the core 2 to varying degrees in the direction of the chord 16 of the blade 1. Furthermore, the lengths of the outer shell 3 and / or the inner cooling chamber 8 can differ on the opposite side legs 14 of the U-shape of the outer shell 3. For example, the length on one pressure side can be different. REHBERG HÜPPE + PARTNER - 18 - Originally submitted version 22023PCT 10.11.2025

[0093] The blade 1 may differ from the suction side of the blade 1. It is recommended that the outer shell 3 and / or the inner cooling chamber 8 be designed at least up to a position with a maximum profile thickness 17 of the blade 1. A design such as that shown in Fig. 1 is particularly preferred, i.e., with an overlap of approximately 70% to 80% of a maximum profile depth 16 of the blade 1. REHBERG HÜPPE + PARTNER - 19 - Originally submitted version 22023PCT 10.11.2025

[0094] REFERENCE MARK LIST

[0095] 1 shovel

[0096] 2 cores

[0097] 3 Outer shell

[0098] 4 feed channel

[0099] 5 Passage channel

[0100] 6 Outside

[0101] 7 Inside

[0102] 8 Indoor cold storage

[0103] 9 trailing edge

[0104] 10 Outlet

[0105] 11 Bridge

[0106] 12 Front

[0107] 13 U-profile

[0108] 14 Side thigh

[0109] 15 Longitudinal extent

[0110] 16 profile depth

[0111] 17 Profile thickness

[0112] 18 Connecting element

[0113] 19 Outlet opening

[0114] 20 Corner

[0115] Page 21

[0116] Page 22

[0117] Page 23

[0118] 24 Outside

[0119] 25 Undercut

[0120] 26 End range

Claims

REHBERG HÜPPE + PARTNER - 20 - Originally submitted version 22023PCT 10.11.2025 PATENT CLAIMS 1. Blade (1) for a turbine or compressor, comprising an inner core (2) and an outer shell (3) partially surrounding the core (2), wherein the core (2) has at least one supply channel (4) for cooling fluid and wherein the core (2) has passage channels (5) connecting the supply channel (4) to an inner cooling chamber (8) formed between an outer surface (6) of the core (2) and an inner surface (7) of the outer shell (3), wherein the inner cooling chamber (8) has a flow connection to an outlet (10) formed by the core (2) in the region of a trailing edge (9) of the blade (1), wherein the outer shell (3) is preformed into a U-profile (13), wherein the U-profile (13) has two opposing side legs (14), characterized in that the side legs (14) are preformed such that a force is applied to the outer shell (3) via a connecting element (18) at room temperature.which is guided through the core (2) in the area of ​​the trailing edge (9) of the blade (1).

2. Shovel (1) according to claim 1, wherein webs (11) are formed in the inner cooling chamber (8) via which the inner side (7) of the outer shell (3) is supported on the core (2).

3. Shovel (1) according to claim 2, wherein the webs (11) are formed from the core (2).

4. Shovel (1) according to claim 2 or 3, wherein the outer shell (3) is detachably supported on end faces (12) of the webs (11).

5. Shovel (1) according to one of the preceding claims, wherein the outer shell (3) has an elastic, resilient material and / or is pre-formed such that a restoring force of the outer shell (3) presses the outer shell (3) against the core (2) under operating conditions.

6. Shovel (1) according to claim 5, wherein the outer shell (3) has a U-profile (13) with elastic widening of the side legs (14) and / or a profile twisted over a longitudinal extension (15) of the shovel (1).

7. Shovel (1) according to one of the preceding claims, wherein the outer shell (3) comprises an anisotropic material whose structure is oriented such that the outer shell (3) when REHBERG HÜPPE + PARTNER - 21 - Originally submitted version 22023PCT 10.11.2025 When heated, the outer shell (3) undergoes a change in shape, which generates a contact force between the outer shell (3) and the core (2).

8. Blade (1) according to one of the preceding claims, wherein the outer shell (3) is elastically deformed according to the arrangement on the core (2) such that an outer surface (24) of the outer shell (3) is subject to a tensile stress which is reduced and / or compensated when the outer shell (3) is heated.

9. Blade (1) according to one of the preceding claims, wherein the outer shell (3) and / or the inner cooling chamber (8) covers the core (2) in the direction of a profile depth (16) of the blade (1) over at least 30% of the maximum profile depth (16) up to a maximum of 95% of the maximum profile depth (16).

10. Blade (1) according to one of the preceding claims, wherein the outer shell (3) and / or the inner cooling chamber (8) covers the core (2) at least up to a position of a maximum profile thickness (17) of the blade (1).

11. Blade (1) according to one of the preceding claims, wherein the outer shell (3) comprises a ceramic material and / or a fiber ceramic material and / or SiC fibers embedded in a SiC matrix.

12. Shovel (1) according to one of the preceding claims, wherein the core (2) comprises a metal.

13. Shovel (1) according to one of the preceding claims, wherein the passage channels (5) of the core (2) have different sizes and / or distances from each other.

14. Shovel (1) according to one of the preceding claims, wherein the outer shell (3) is connected to the core (2) by a material bond and / or a form-fit bond.

15. Shovel (1) according to one of the preceding claims, wherein the core (2) has an undercut (25) into which an end region (26) of the outer shell (3) that points towards the rear edge (9) of the shovel (1) engages in a form-fitting manner. REHBERG HÜPPE + PARTNER - 22 - Originally submitted version 22023PCT 10.11.2025 16. Blade (1) according to one of the preceding claims, wherein the outlet (10) has a plurality of outlet openings (19) formed in the core (2), which are arranged one behind the other in the longitudinal extension (15) of the blade (1).

17. Shovel (1) according to one of the preceding claims, wherein the inside (7) of the outer shell (3) has a texture and / or ribs which are preferably recessed in the area of ​​contact points of the outer shell (3) with the core (2).

18. Blade (1) according to one of the preceding claims, wherein the core (2) has a triangular cross-section, wherein a corner (20) of the triangular cross-section forms the trailing edge (9) of the blade (1), wherein a region of the core (2) defining the outer shell (3) and the inner cooling chamber (8) extends from the side (21) of the triangular cross-section opposite the corner (20) to the trailing edge (9), and wherein an outer surface (24) of the outer shell (3) transitions flush into two sides (22, 23) of the triangular cross-section adjacent to the corner (20).

19. Compressor or turbine with a blading arrangement consisting of a plurality of guide vanes and / or rotor blades, wherein at least one guide vane and / or rotor blade is designed as a blade (1) according to one of the preceding claims.

20. Method for manufacturing a blade (1) designed according to any one of claims 1 to 18, wherein the outer shell (3) is formed in a u-shape from a starting material before being connected to the core (2) and the preformed u-shaped outer shell (3) is then pushed onto the core (2) in the direction of the longitudinal extent (15) of the blade (1).

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