Rotor blade for a turbomachine and method for producing a rotor blade

Abstract

The invention relates to a rotor blade (1) for a turbomachine, comprising: a blade airfoil region (2) and a blade root region (3), wherein the rotor blade (1) has at least one fiber composite component (4) made of a fiber composite material and a surrounding part (5), and the surrounding part (5) completely surrounds the fiber composite component (4). The invention also comprises a method for producing such a rotor blade (1).

Description

Background Art

[0001] The rotor blades of turbomachines are subjected to severe loads, in particular by centrifugal forces, and should be dimensioned accordingly. In particular, in the case of large blade lengths or high rotational speeds, the rotor blades can only be manufactured using high-strength materials or eventually even no longer be manufactured. The rotor blades at different rotational speeds can be shaped by the dimensions A*n 2 By analogy, where A is the area skipped and n is the rotational speed.

[0002] It is known that in the case of large rotor blades, they should be manufactured from fiber composite materials. The high specific strength of fiber composite materials (especially CFRP) is used in this case to achieve large blade lengths even at high rotational speeds. However, fiber composite materials have some properties that also hinder their widespread use in turbomachines:

[0003] -Strongly direction-dependent strength and stiffness. The maximum value is reached parallel to the fiber direction, and the strength and stiffness are about an order of magnitude smaller perpendicular to the fiber direction.

[0004] This places the design of highly loaded contact surfaces (such as the blade root) at structural limits, in particular, since transverse forces have to be transmitted. This is currently a limiting factor for the achievable blade length.

[0005] o In order to achieve a sufficiently torsionally rigid blade airfoil, fibers are necessary not only in the main load direction, but also in deviating directions (+ / -30°, + / -45°). These make a smaller contribution to the load carrying capacity.

[0006] - Damage caused by media influences and mechanical effects.

[0007] o Media influences can lead to changes in material properties, for example through the accumulation of water when used in steam turbines. This leads to a time-dependent loss of strength and can ultimately lead to component failure. In the case of use as compressor blades for gas turbines, moisture in the inflowing air can also lead to water accumulation. This applies in particular when water is injected into the intake air.

[0008] o can only withstand mechanical effects to a small extent (particularly transversely to the fiber direction). If the location of the effect is limitable, protective components (e.g. protective strips in the drive mechanism fan blades) can be provided here. In the case of steam turbines, the following solutions are known: local protective strips are installed on the low-pressure blades to prevent droplet erosion. In this case, a reliable connection between the protective strip and the composite material that withstands vibrations and centrifugal forces is a major challenge. Summary of the invention

[0009] Starting from the prior art, the object of the present invention is to specify a fiber-reinforced rotor blade for a turbomachine and a method for producing such a rotor blade, which coordinates the properties of the composite material with the requirements in the turbomachine and thus enables long-term use. This object is achieved with respect to the rotor blade by the features of an exemplary embodiment of the invention and with respect to the method by the features of an exemplary embodiment of the invention.

[0010] Advantageous embodiments and developments of the invention, which can be used individually or in combination with one another, are the subject matter of the following exemplary embodiments.

[0011] The rotor blade according to the invention for a turbomachine is characterized by a blade airfoil region and a blade root region, wherein the rotor blade has at least one fiber composite component made of a fiber composite material and a surround, and the surround completely surrounds the at least one fiber composite component.

[0012] Due to the complete envelopment of the fiber composite component, the fiber composite component is reliably shielded from the influence of the medium, thereby effectively preventing any loss of strength. This is an essential prerequisite for long-term use.

[0013] One embodiment of the invention provides that the enclosure includes contact elements. All areas of the rotor blade that are in contact with adjacent components can be considered contact elements, such as the blade root area, which engages in a groove in the rotor, or the cover plate or the vibration-damping tie rod, which is supported against the adjacent rotor blade in order to reduce vibrations. The embedding of the contact element in the enclosure allows high contact pressures and thus large blade lengths.

[0014] Another design of the present invention proposes that the enclosure is made of a metal material and surrounds at least one fiber composite component in a pressure-tight manner, wherein the pressure seal relates to the pressure commonly expected during operation. The enclosure made of a metal material allows a high contact pressure at the contact element, especially at the blade root, and thus allows a large blade length. The pressure-tight closure of the enclosure is carried out after the introduction of at least one fiber composite component by one of the following connection types: material fit (e.g. welding, soldering, bonding), form fit (e.g. insertion, snap-in, latching, bolting) or force fit (e.g. threaded connection, shrink fit). The connection can also be manufactured by additive manufacturing (geometric coating). Combinations of these connection types can also be implemented.

[0015] The introduction of at least one fiber composite component is to be understood as the positioning of the fiber composite component in the provided cavity or the positioning of the fiber composite component on the inner side of the blade component and the subsequent closing of the inner side by means of the blade component. Due to high vibration loads, a stable and reliable closure is desired. In the case of metal enclosures, welded connections (sealing welds) are already put to the test. In this case, the process control (heat introduced, spacing of the weld seams) ensures that the fiber composite material is not overheated and damaged.

[0016] Another embodiment of the invention provides that at least one fiber composite component is prestressed relative to the surrounding part. The prestressing of the fiber composite component relative to the surrounding part relieves the surrounding part from load and results in a high load-bearing capacity of the entire cross section (fiber composite component+surrounding part).

[0017] A particularly advantageous embodiment of the invention provides that at least one fiber composite component is prestressed in the main load direction of the rotor blade. In contrast to the prestressing of the surrounding part in the main load direction of the fiber composite component, the surrounding part is thus subjected to a compressive prestressing. The fiber composite component can be optimized for mainly unidirectional force transmission, while the surrounding part can absorb torsional forces, bending forces and warping forces.

[0018] Another embodiment of the present invention provides that at least one fiber composite component is fixed to the surrounding part at at least two locations. By fixing at least one fiber composite component to the surrounding part at two locations, an optimal prestressing of the fiber composite component relative to the surrounding part can be achieved.

[0019] One embodiment of the invention provides that at least one fiber composite component is fastened in or near the blade root region and in the blade airfoil region. For the transmission of forces, it has proven to be advantageous to fasten the fiber composite component in or near the blade root region and again in the blade airfoil region. For the transmission of forces, it has also proven to be advantageous to guide the fiber composite component in the blade airfoil region substantially in the main load direction of the rotor blade.

[0020] Another embodiment of the invention provides that the rotor blade has at least one hole axial / parallel to the fibers in the enclosure and a bushing is arranged in the hole, to which at least one fiber composite component is fastened. The type of fastening is very important for load-bearing capacity and reliability.

[0021] An embodiment has proven to be particularly suitable in this regard, in which the force input into the fiber composite component is essentially carried out via shear stress. As a result, excessive loading of the fiber composite component can be avoided. Therefore, at least one fiber composite component can be fixed by means of a bushing arranged in a hole arranged axially / parallel to the fibers. Such a bushing can be inserted into the blade in a fixed position (in a fixed receptacle) or in an adjustable manner. Adjustability can be achieved, for example, by screw connections, wedges, fittings, etc. The fixation can then be ensured by a direct closure (e.g. a weld) or a separate (e.g. welded) cover. Fixed-position fixation can also be achieved by direct bonding / lamination to the inner side of the enclosure. The position can then be closed by a cover mounted in a pressure-tight manner.

[0022] A first method according to the invention for producing a rotor blade is characterized by comprising the following method steps:

[0023] - forming at least one fiber composite component;

[0024] - forming a surrounding part, wherein the surrounding part has an opening for introducing at least one fiber composite component; - introducing at least one prefabricated fiber composite component into the surrounding part;

[0025] The opening in the enclosure is closed in a pressure-tight manner by means of a separate closing element or by means of the blade component, in particular the blade root region.

[0026] In the method, the fiber composite component and the surrounding part are firstly produced separately and then at least one prefabricated fiber composite component is introduced into the surrounding part through an opening in the surrounding part.

[0027] The pressure-tight closure of the enclosure can be achieved after the at least one fiber composite component has been introduced, preferably by one of the following types of connection: material fit (e.g. welding, soldering, adhesive bonding), form fit (e.g. plug-in, snap-in, latching, screw connection) or force fit (e.g. screw connection, shrink fit). The connection can also be additively manufactured (geometric coating). Combinations of these types of connection can also be implemented.

[0028] The introduction of at least one fiber composite component is to be understood as the positioning of the fiber composite component in the provided cavity or the positioning of the fiber composite component on the inner side of the blade component and the subsequent closing of the inner side by means of the blade component. Due to the high vibration loads, a stable and reliable closure is sought. In the case of metal enclosures, welded connections (sealing welds) are already put to the test. In this case, the process control (heat introduced, spacing of the weld seams) ensures that the fiber composite material is not overheated and damaged.

[0029] An advantageous embodiment of the method is characterized in that at least one fiber composite component is prestressed relative to the surrounding part. The prestressing of the fiber composite component relative to the surrounding part relieves the surrounding part from load and results in a high load-bearing capacity of the entire cross section (fiber composite component+surrounding part). The prestressing is essentially carried out relative to the surrounding part in the main load direction of the fiber composite component, which is thus subjected to pressure prestressing. The fiber composite component can be optimized for mainly unidirectional force transmission, while the surrounding part can absorb torsional forces, bending forces and warping forces. It is advantageous to guide the fiber composite component in a vibration-proof manner, for example by lateral guidance or slight squeezing at the surrounding part.

[0030] A further embodiment of the method is characterized in that the prestressing is achieved by the following method steps: - introducing at least one fiber composite component into the enclosure;

[0031] - the fiber composite component is preferably first fixed in the upper blade airfoil region;

[0032] - cooling the fiber composite and the surrounding part to a temperature of at least -20°C, preferably below -60°C; - secondly fixing the fiber composite component, preferably in the lower airfoil region;

[0033] - Heating the fiber composite component and the surrounding part to at least ambient temperature.

[0034] In order to preload the fiber composite component, very high local forces are required during mechanical introduction. Therefore, it has proven to be advantageous to use the different thermal expansion properties of the fiber composite material and the conventional surrounding material. The fiber composite material shrinks at elevated temperatures or has only a minimal positive thermal expansion (typically <1*10 -6 1 / K). In contrast, common steel materials for rotor blades are in the range of 12…16*10 -6 1 / K. In order to utilize the different ductility properties, the fiber composite component is introduced into the surrounding part and is preferably fixed on one side. Subsequently, the component (surrounding part and fiber composite component) is cooled to a temperature below -20°C, preferably below -60°C. The fiber composite component is then at least further fixed to the surrounding part and the component is subsequently heated. Thus, prestressing values ​​of several hundred MPa up to >1000 MPa (fiber stress) are achieved, depending on the fiber composite material.

[0035] The type of fastening is very important for load-bearing capacity and reliability. In this regard, embodiments suitable for bonding have proven to be particularly suitable, in which the force input into the fiber composite component occurs essentially via shear stresses. This makes it possible to avoid excessive loading of the composite component.

[0036] One embodiment of the method provides that the fiber composite component is fixed by means of a bushing which is introduced into a hole arranged axially / parallel to the fibers in the surrounding part. Such a bushing can then be inserted into the blade in a fixed position (in a fixed receptacle) or in an adjustable manner. Adjustability can be achieved, for example, by (fastenable) screw connections, wedges, fittings, etc. The fixing can then be ensured by a direct closure (for example a weld) or a separate (for example welded) cover. Fixed-position fixing can also be achieved by direct bonding / lamination to the inner side of the surrounding part.

[0037] A second method according to the invention for producing a rotor blade is characterized by comprising the following method steps:

[0038] - forming an enclosure, wherein the enclosure has an opening;

[0039] - placing the semi-finished product through the opening on the inner wall of the surrounding part;

[0040] - impregnation of the semi-finished product with the matrix material;

[0041] - hardening the matrix material;

[0042] The opening in the enclosure is closed in a pressure-tight manner by means of a separate closing element or by means of the blade component, in particular the blade root region.

[0043] The positionally fixed fixing is achieved here by direct bonding / lamination to the inner side of the enclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other advantages and configurations of the present invention are described below with reference to the accompanying drawings.

[0045] The accompanying drawings show:

[0046] Figure 1 The basic design of a rotor blade according to the invention is shown in a side view.

[0047] Figure 2 A first exemplary embodiment of a rotor blade according to the invention is shown in a cross-sectional view.

[0048] Figure 3 A second exemplary embodiment of a rotor blade according to the invention is shown in a cross-sectional view.

[0049] Figure 4 A third exemplary embodiment of a rotor blade according to the invention is shown in a cross-sectional view.

[0050] Figure 5 Show Figure 4 Detail view of detail Z in,

[0051] Figure 6 Shown along Figure 4A cross-sectional view of the rotor blade along line AA,

[0052] Figure 7 Show Figure 4 The detail view of the detail y in the

[0053] Figure 8 Show Figure 4 Details in X1 detail view,

[0054] Fig. 9 A fourth exemplary embodiment of a rotor blade according to the invention is shown in a cross-sectional view.

[0055] Fig.10 Show Fig. 9 Details in Detail view of X2. DETAILED DESCRIPTION

[0056] Identical or functionally identical components are provided with the same reference numerals in all the figures. The figures are intended to explain the principle of the invention in more detail, wherein only the essential components necessary for the invention are shown. The figures are not necessarily true to scale.

[0057] Figure 1 The basic structure of a rotor blade 1 for a fluid machine such as a steam turbine according to the present invention is shown. The rotor blade 1 includes a blade body area 2 and a blade root area 3. The rotor blade 1 has a plurality of fiber composite components 4 and a surrounding member 5 made of fiber composite materials. The surrounding member 5 completely surrounds the fiber composite component 4. Due to the complete surrounding of the fiber composite component 4, the fiber composite component is reliably shielded from the influence of the medium, thereby effectively preventing possible strength loss. This is the main prerequisite for the long-term use of fiber composite materials. When used in a steam turbine, the influence of the medium may cause changes in material properties, for example due to the storage of water. This causes a time-dependent strength loss and may eventually cause component failure. When used as a compressor blade for a gas turbine, the moisture of the inflowing air can also cause water storage. This is particularly applicable when water is sprayed into the suction air.

[0058] Furthermore, the fiber composite material (particularly transversely to the fiber direction) can only withstand mechanical effects to a small extent, and the enclosure 5 also effectively protects the fiber composite material. The enclosure 5 itself can also be designed to be locally reinforced (e.g. welded, hardened, coated with hard material) in the area 15 that is subject to special loads. Such an area 15 that is subject to special loads can be, for example, the front edge of the rotor blade 1.

[0059] The enclosure 5 consists of a metallic material and surrounds all necessary contact elements. Contact elements are considered to be all areas of the rotor blade that come into contact with adjacent components, such as the blade root area 3 that engages in a groove in the rotor or the cover plate 16 or the vibration-damping braces 17 that are supported relative to the adjacent rotor blade to reduce vibrations. The embedding of the contact elements 3, 16, 17 in the enclosure 5 allows high contact pressures and thus large blade lengths.

[0060] Figure 2 The cross-sectional view shows the Figure 1 A first embodiment of a rotor blade 1 is provided. The rotor blade 1 comprises a plurality of, in the embodiment four, individual fiber composite components 4 in the form of fiber bundles. Such a fiber bundle can, for example, consist of a plurality of individual fibers interwoven with one another. The individual fiber composite components 4 are fixed at two locations 6, 7 on the enclosure 5 and are prestressed relative to the enclosure 5. It has proven to be advantageous here that the fiber bundles are fixed on the one hand in the blade airfoil region 2 close to the blade tip and on the other hand in the blade root region 3 or in the vicinity of the blade root region 3. As a result, the fixing points are spatially distant from one another, thereby making it possible to achieve high prestressing forces. For the prestressing of the fiber composite components 4, very high local forces are required in the case of mechanical introduction. Therefore, it has proven to be advantageous to utilize the different thermal expansion properties of fiber composite materials and conventional enclosure materials. Fiber composite materials shrink when the temperature increases or have only a minimal positive thermal expansion (typically <1*10 -6 1 / K). In contrast, conventional steel materials for rotor blades 1 are in the range of 12...16*10 -6 1 / K. In order to utilize the different ductility properties, the fiber composite component 4 is introduced into the surrounding part 5 and the fiber composite component is preferably fixed on one side. Subsequently, the component (surrounding part and fiber composite component) is cooled to a temperature below -20°C, preferably below -60°C. Then, at least the fiber composite component 4 is further fixed to the surrounding part 5 and the component is subsequently heated (for example, by heating with ambient temperature). Thus, prestressing values ​​of several hundred MPa up to >1000 MPa (fiber stress) are achieved depending on the fiber composite material.

[0061] After the fiber composite component 4 has been prestressed, the enclosure 5 is closed in a pressure-tight manner, which can be done either directly with the blade component (root section) or with the aid of a separate cover. The closing can be done by material fit (e.g. welding, soldering, adhesive bonding), form fit (e.g. plugging, snap-in, latching, screwing) or force fit (e.g. screwing, shrink fit). The connection can also be additively manufactured (geometric coating). Combinations of these types of connections can also be implemented.

[0062] Due to the high vibration loads, a stable and reliable closure is required. In the case of metal enclosures, welding (sealing welding) has been put to the test. In this case, the process control (heat introduced, spacing of the weld seams) ensures that the fiber composite material is not overheated and damaged.

[0063] The prestressing of the fiber composite component 4 relative to the surrounding part 5 is essentially carried out in the main load direction of the fiber composite component. The surrounding part is thus subjected to compressive prestressing. The fiber composite component 4 is optimized for mainly unidirectional force transmission, while the surrounding part 5 can absorb torsional forces, bending forces and warping forces.

[0064] Figure 3 A second embodiment of a rotor blade 1 according to the invention is shown in cross section. The basic design of the rotor blade 1 corresponds to that of Figure 2 The construction described in Figure 2 In contrast to the design of the rotor blade 1, the rotor blade 1 does not have a separate fiber composite component 4 designed as a fiber bundle, but rather a prefabricated fiber composite from a plurality of fiber bundles, which is introduced as a whole into the surrounding part 5 through an opening 10 in the surrounding part 5 and prestressed. The opening 10 is then closed pressure-tightly with a cover or blade root region 3. This facilitates the assembly and prestressing of the fiber composite component 4.

[0065] Instead of prefabricated fiber composite components, the fiber composite can also be formed by inserting semi-finished products (filaments, textiles, fabrics) and subsequently impregnating them with a matrix material.

[0066] Figure 4 A third embodiment of a rotor blade 1 according to the invention is shown in cross section. Figure 2 Like the rotor blade 1 of FIG. 1 , the rotor blade 1 has a separate fiber composite component 4 designed as a fiber bundle, which is prestressed relative to the surrounding part 5. The fiber composite component 4 is fixed in a bushing 9, which is arranged in a hole 8 axially / parallel to the fiber formation in the surrounding part 5. The vibration-damping guide 18 of the fiber composite component 4 prevents individual vibrations of the fiber composite component 4. The detailed design of the bushing 9 and the vibration-damping guide 18 of the fiber composite component 4 is explained in detail with reference to the following figures. The figures here each relate to Figure 4 Details described in .

[0067] Figure 5 Show Figure 4 Detail Z in the drawing relates to the fastening of the fiber composite component 4 in the blade airfoil region 2 by means of a bushing 9. The bushing 9 is arranged in a fixed position in a hole 8 in the surround 5. The fastening is carried out by direct bonding / lamination between the inner side of the bushing 9 and the outer side of the fiber composite component 4. The bushing 9 has a shoulder 19, with which it is supported against a recess 20 in the surround 5.

[0068] Figure 6 Shown along Figure 4 Detailed view of the fixation of the position of the line AA in FIG. The fixation here corresponds essentially to the fixation already in FIG. Figure 5 The fixing described in , in which the bushing 9 is arranged in a fixed position in the central hole 8 in the enclosure 5 and is supported at the recess 20. Figure 6 The production of a pressure-tight closure of the opening 10 by means of a separate (eg welded) cover 21 or alternatively by means of a direct closure (eg a weld seam) is shown.

[0069] Figure 7 Show Figure 4 Detail Y in the figure relates here to the fastening of the fiber composite component 4 in the blade root region 3 by means of a bushing 9. The bushing 9 is inserted adjustably in the hole 8 of the enclosure 5. The adjustability is achieved by means of a screw connection 22. Alternatively, the adjustability can also be achieved, for example, by means of a wedge, a fitting, etc. After the bushing 9 has been positioned, it is then closed by means of a cover 21 which is mounted in a pressure-tight manner.

[0070] Figure 8 Show Figure 4 In the detail view of FIG. 4 , the vibration-damping guide 18 of the fiber composite component 4 can be seen. The vibration-damping guide 18 prevents the fiber composite 4 from vibrating individually.

[0071] exist Fig. 9 The vibration-damping guidance is achieved by guiding the fiber composite in a slight arc. Detailed view of the arc guidance as Fig.10 The detail X2 in FIG. 1 shows that the fiber composite component 4 here rests against the inner side of the arc of the rotor blade 1 .

[0072] The vibration damping guidance can also be achieved by casting or geometric guidance (side pads). In summary, it can be seen that the rotor blade according to the invention is the first to adapt the properties of composite materials to the requirements in turbomachines and thus enables long-term use.

Claims

1. A rotor blade (1) for a fluid machine, comprising: A rotor blade (1) having at least one fiber composite component (4) made of a fiber composite material and a surrounding part (5), wherein the surrounding part (5) completely surrounds the fiber composite component (4), characterized in that the fiber composite component (4) is prestressed relative to the surrounding part (5).

2. The rotor blade (1) according to claim 1, It is characterized in that The enclosure (5) comprises contact elements.

3. The rotor blade (1) according to claim 1 or 2, It is characterized in that The enclosure (5) consists of a metallic material and surrounds the fiber composite component (4) in a pressure-tight manner.

4. The rotor blade (1) according to claim 1 or 2, It is characterized in that The fiber composite component (4) is prestressed in the main load direction of the rotor blade (1).

5. The rotor blade (1) according to claim 1 or 2, It is characterized in that At least a part of the fiber composite component (4) is fastened to the surrounding element (5) at least one first location (6) and at least one second location (7).

6. The rotor blade (1) according to claim 5, It is characterized in that The fiber composite component (4) is fastened in or near the blade root region (3) and in the blade airfoil region (2).

7. The rotor blade (1) according to claim 1 or 2, It is characterized in that The fiber composite component (4) is guided in the airfoil region (2) essentially in the main load direction of the rotor blade (1).

8. The rotor blade (1) according to claim 1 or 2, It is characterized in that The rotor blade (1) has at least one axial hole (8) or a hole (8) parallel to the fibers in the enclosure (5), and at least one bushing (9) is arranged in the hole (8), to which at least one fiber composite component (4) is fastened.

9. The rotor blade (1) according to claim 8, It is characterized in that The at least one bushing (9) is arranged in a fixed position.

10. The rotor blade (1) according to claim 8, It is characterized in that The at least one bushing (9) is designed to be adjustable.

11. The rotor blade (1) according to claim 1, It is characterized in that The enclosure (5) includes the blade root region (3).

12. A method for producing a rotor blade (1) according to any one of claims 1 to 11, It is characterized in that The method comprises the following steps: - forming the fiber composite component (4); - forming the enclosure (5), wherein the enclosure has an opening (10) for introducing the fiber composite component (4); - introducing the prefabricated fiber composite component (4) into the surrounding element (5); - closing the opening (10) in the enclosure (5) in a pressure-tight manner by means of a separate closure (11) or by means of a blade element; - Prestressing the fiber composite component (4) relative to the surrounding element (5).

13. Method for producing a rotor blade (1) according to claim 12, It is characterized in that The pre-tightening is achieved by the following method steps: - introducing the fiber composite component (4) into the surrounding element (5); - first fixing the fiber composite component (4); - cooling the fiber composite component (4) and the surrounding element (5) to a temperature of at least -20°C; - secondly fixing the fiber composite component (4); - heating the fiber composite component (4) and the surrounding element (5) to at least ambient temperature.

14. Method for producing a rotor blade (1) according to claim 13, It is characterized in that Bushings (9) are introduced into axial holes (8) or holes (8) parallel to the fibers in the enclosure (5), by means of which the fiber composite component (4) is fixed.

15. Method for producing a rotor blade (1) according to claim 14, It is characterized in that The bushing (9) is inserted into a fixed receptacle (12) in the enclosure (5) in a positionally fixed manner.

16. Method for producing a rotor blade (1) according to claim 14, It is characterized in that The bushing (9) is adjustably inserted into the enclosure (5).

17. Method for producing a rotor blade (1) according to claim 16, It is characterized in that The adjustability is achieved by means of a screw connection (13), a wedge, a fitting or a separate cover (14).

18. Method for producing a rotor blade (1) according to claim 12, It is characterized in that The blade component is the blade root region (3).

19. Method for producing a rotor blade (1) according to claim 13, It is characterized in that The temperature is below -60°C.

20. Method for producing a rotor blade (1) according to claim 13, It is characterized in that The first fixing includes: - The fiber composite component (4) is fixed in the upper blade airfoil region (2).

21. Method for producing a rotor blade (1) according to claim 13, It is characterized in that The second fixing includes: The fiber composite component (4) is fixed in the lower part of the blade airfoil region (2) or in the blade root region (3).

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