Fan blade with hollow structure and turbofan engine

Abstract

The invention relates to a fan blade of a hollow structure and a turbofan engine. The fan blade of the hollow structure comprises a blade back and a blade basin, and the blade back and the blade basin are connected together at the blade tip and the blade root of the fan blade of the hollow structure respectively, so that an inner cavity is defined. The fan blade of the hollow structure further comprises a plurality of carbon fiber mixed reinforcement bodies arranged in the inner cavity, and at least some of the carbon fiber mixed reinforcement bodies are connected between the blade tip and the blade root so as to integrally reinforce the inner cavity of the fan blade of the hollow structure. Wherein each carbon fiber mixed reinforcement in the plurality of carbon fiber mixed reinforcements comprises a metal wire positioned in the center and carbon fibers twisted by taking the metal wire as a central axis. The fan blade has the beneficial technical effects that the internal hollow structure of the fan blade is simple, and the obvious weight reduction advantage is achieved.

Description

Technical Field

[0001] The present invention relates to the field of aviation technology, and particularly to a hollow-structured fan blade and a turbofan engine including the hollow-structured fan blade. Background Art

[0002] Modern aviation turbofan engines require higher thrust-to-weight ratios and higher performance. To increase the thrust and thrust-to-weight ratio of the engine, it is necessary to reduce the structural weight of the engine to improve engine efficiency. For this purpose, in addition to improving and optimizing the overall design of the engine, it is also necessary to develop more advanced lightweight and high-performance new materials and more efficient integrated and lightweight structural components. As the most important component of an aviation engine, the reduction of the weight of the fan blade can bring significant weight reduction benefits. Foreign aviation engine OEMs, such as Rolls-Royce, mainly use titanium alloy hollow corrugated structure fan blades, and General Electric mainly uses resin matrix composite fan blades to achieve the purpose of reducing weight, further improving engine performance and increasing the thrust-to-weight ratio.

[0003] At present, the mature and applied titanium alloy hollow fan blade is the third-generation corrugated structure fan blade of Rolls-Royce. This blade is formed by titanium alloy plates through superplastic forming + diffusion bonding process, and its internal structure is a typical corrugated structure, and its maximum hollowness rate can reach about 40%.

[0004] However, the existing hollow fan blades still have the following main problems:

[0005] 1. The internal hollow structure is complex: The internal cavity area of the existing titanium alloy hollow fan blade is a corrugated structure, and the thickness of both the blade's pressure side and suction side and the core plate change in different regions of the blade body. There are many design parameters, which are difficult to control and achieve the optimal ratio.

[0006] 2. It is difficult to further increase the equivalent hollowness rate: Considering that the blade must ensure sufficient overall stiffness, blade body strength, and anti-bird strike performance, the hollow area can only be limited to the middle area of the blade body. In addition, the internal cavity of this blade is formed by a corrugated structure, and the corrugated structure itself occupies a large amount of internal space, making it difficult to further increase its equivalent hollowness rate after reaching a certain level.

[0007] 3. For small-sized fan blades, the increase in the equivalent hollowness rate is difficult to bring significant weight reduction benefits and cannot achieve the weight reduction effect. Summary of the Invention

[0008] An object of the present invention is to provide a hollow-structured fan blade, which can solve the problems existing in the prior art. The internal hollow structure of the fan blade is simple and has obvious weight reduction advantages.

[0009] The above object of the present invention is achieved by a hollow-structured fan blade, which includes a blade back and a blade bowl. Wherein, the blade back and the blade bowl are respectively connected together at the blade tip and the blade root of the hollow-structured fan blade, thereby defining an internal cavity;

[0010] The hollow-structured fan blade further includes a plurality of carbon fiber hybrid reinforcements disposed in the internal cavity. At least some of the plurality of carbon fiber hybrid reinforcements are connected between the blade tip and the blade root to integrally reinforce the internal cavity of the hollow-structured fan blade;

[0011] Wherein, each of the plurality of carbon fiber hybrid reinforcements includes a metal wire at the center and carbon fibers twisted with the metal wire as the central axis.

[0012] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: The internal hollow structure of the fan blade is simple and has an obvious weight reduction advantage.

[0013] Preferably, at least some of the other carbon fiber hybrid reinforcements among the plurality of carbon fiber hybrid reinforcements are connected between the blade tip and the leading edge or the trailing edge of the hollow-structured fan blade.

[0014] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: The carbon fiber hybrid reinforcements can cover the internal cavity of the hollow-structured fan blade, thereby better integrally reinforcing the internal cavity of the hollow-structured fan blade.

[0015] Preferably, the internal cavity of the hollow-structured fan blade includes a plurality of sub-cavities arranged in a "mouth" or "pin" shaped matrix.

[0016] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: It can enhance the overall rigidity of the hollow-structured fan blade.

[0017] Preferably, the twist of the carbon fiber is 18 to 25 twists per meter.

[0018] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through an appropriate twist of the carbon fiber, it is ensured that the carbon fiber can provide sufficient stiffness performance and protect the carbon fiber, and can better integrally reinforce the internal cavity of the hollow-structured fan blade.

[0019] Preferably, the carbon fiber is preliminarily infiltrated with epoxy resin.

[0020] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable carbon fiber infiltration process, the internal cavity of the hollow-structured fan blade can be better strengthened as a whole.

[0021] Preferably, the metal wire is a titanium alloy wire.

[0022] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through the central metal wire of the carbon fiber hybrid reinforcement of a suitable material, the internal cavity of the hollow-structured fan blade can be better strengthened as a whole.

[0023] Preferably, at least some of the multiple carbon fiber hybrid reinforcements are connected between the blade tip and the blade root by atomic diffusion.

[0024] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable connection process of the carbon fiber hybrid reinforcement, the internal cavity of the hollow-structured fan blade can be better strengthened as a whole.

[0025] Preferably, the multiple carbon fiber hybrid reinforcements are arranged in multiple parallel planes.

[0026] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable arrangement method of the carbon fiber hybrid reinforcement, the internal cavity of the hollow-structured fan blade can be better strengthened as a whole.

[0027] Preferably, the number of carbon fiber hybrid reinforcements per unit area is 40 - 60 per square decimeter.

[0028] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable arrangement density of the carbon fiber hybrid reinforcement, the internal cavity of the hollow-structured fan blade can be better strengthened as a whole.

[0029] The above object of the present invention is also achieved by a turbofan engine, wherein the turbofan engine includes the hollow-structured fan blade as described in any of the foregoing aspects.

[0030] According to the above technical solution, the turbofan engine of the present invention can achieve the following beneficial technical effects: The internal hollow structure of the fan blade is simple and has an obvious weight reduction advantage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is an overall schematic diagram of a hollow-structured fan blade according to an embodiment of the present invention.

[0032] Figure 2It is a schematic diagram of the internal cavity of a hollow-structured fan blade according to an embodiment of the present invention.

[0033] Figure 3A It is a schematic diagram of an internal sub-cavity of a hollow-structured fan blade according to an embodiment of the present invention.

[0034] Figure 3B It is a schematic diagram of another internal sub-cavity of a hollow-structured fan blade according to an embodiment of the present invention.

[0035] Figure 4 It is a schematic diagram of the cross-section of the internal sub-cavity of a hollow-structured fan blade according to an embodiment of the present invention.

[0036] Figure 5 It is a schematic diagram of the characteristics of the internal sub-cavity of a hollow-structured fan blade according to an embodiment of the present invention.

[0037] Figure 6 It is a schematic diagram of the cross-section of the carbon fiber hybrid reinforcement of a hollow-structured fan blade according to an embodiment of the present invention.

[0038] Figure 7 It is a front view schematic diagram of the carbon fiber hybrid reinforcement of a hollow-structured fan blade according to an embodiment of the present invention.

[0039] Figure 8 It is a schematic diagram of the cross-section of a hollow-structured fan blade according to an embodiment of the present invention.

[0040] Figure 9 It is a schematic diagram of the longitudinal section of a hollow-structured fan blade according to an embodiment of the present invention.

[0041] List of reference numerals

[0042] 1, Back of the blade;

[0043] 2, Suction side of the blade;

[0044] 3, Tip of the blade;

[0045] 4, Root of the blade;

[0046] 5, Leading edge;

[0047] 6, Trailing edge;

[0048] 7, Internal cavity;

[0049] 8, Carbon fiber hybrid reinforcement;

[0050] 9, Metal wire;

[0051] 10, Carbon fiber. Detailed implementation manners

[0052] The specific embodiments of the present invention will be described below. It should be noted that in the specific description of these embodiments, for the sake of concise description, this specification cannot describe all features of the actual embodiments in detail. It should be understood that in the actual implementation of any embodiment, just as in the process of any engineering project or design project, in order to achieve the specific goals of the developer and to meet system-related or business-related restrictions, various specific decisions are often made, and these will also change from one embodiment to another. In addition, it should also be understood that although the efforts made in such a development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present invention, some design, manufacturing, or production changes based on the technical content disclosed in this disclosure are just conventional technical means and should not be understood as the content of this disclosure being insufficient.

[0053] Unless otherwise defined, the technical terms or scientific terms used in the claims and the specification should have the ordinary meaning understood by those of ordinary skill in the technical field to which the present invention belongs. The terms "first", "second" and similar terms used in the specification and claims of this patent application do not denote any order, quantity or importance, but are only used to distinguish different components. The terms "a" or "an" and the like do not denote a quantity limitation, but mean that there is at least one. The terms "comprising" or "including" and the like mean that the elements or objects appearing before "comprising" or "including" cover the elements or objects listed after "comprising" or "including" and their equivalent elements, and do not exclude other elements or objects. The terms "connected" or "coupled" and the like are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0054] As the name implies, the term "hollow-structured fan blade" means: a fan blade having an internal cavity (hollow) structure.

[0055] Figure 1 is an overall schematic diagram of the hollow-structured fan blade according to an embodiment of the present invention. Figure 2 is a schematic diagram of the internal cavity of the hollow-structured fan blade according to an embodiment of the present invention. Figure 3A is a schematic diagram of an internal sub-cavity of the hollow-structured fan blade according to an embodiment of the present invention. Figure 3B is a schematic diagram of another internal sub-cavity of the hollow-structured fan blade according to an embodiment of the present invention. Figure 4 is a schematic cross-sectional view of the internal sub-cavity of the hollow-structured fan blade according to an embodiment of the present invention. Figure 5 is a schematic diagram of the characteristics of the internal sub-cavity of the hollow-structured fan blade according to an embodiment of the present invention. Figure 6It is a cross-sectional schematic view of a carbon fiber hybrid reinforcement of a hollow-structured fan blade according to an embodiment of the present invention. Figure 7 It is a front view schematic view of a carbon fiber hybrid reinforcement of a hollow-structured fan blade according to an embodiment of the present invention. Figure 8 It is a cross-sectional schematic view of a hollow-structured fan blade according to an embodiment of the present invention. Figure 9 It is a longitudinal sectional schematic view of a hollow-structured fan blade according to an embodiment of the present invention.

[0056] As Figure 1 — Figure 9 As shown, according to an embodiment of the present invention, the hollow-structured fan blade includes a blade back 1 and a blade bowl 2, wherein the blade back 1 and the blade bowl 2 are connected together at the blade tip 3 and the blade root 4 of the hollow-structured fan blade respectively, thereby defining an internal cavity 7;

[0057] The hollow-structured fan blade further includes a plurality of carbon fiber hybrid reinforcements 8 disposed in the internal cavity 7, and at least some of the plurality of carbon fiber hybrid reinforcements 8 are connected between the blade tip 3 and the blade root 4 to integrally reinforce the internal cavity 7 of the hollow-structured fan blade;

[0058] Wherein, each of the plurality of carbon fiber hybrid reinforcements 8 includes a metal wire 9 located at the center and carbon fibers 10 twisted with the metal wire 9 as the central axis.

[0059] According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: The internal hollow structure of the fan blade is simple and has an obvious weight reduction advantage.

[0060] Specifically, for small-sized hollow fan blades, the use of the traditional corrugated hollow structure cannot achieve the expected weight reduction benefit. Therefore, the present invention proposes a hollow-structured fan blade. Since the cavity in the blade body region is a large cavity structure and the traditional corrugations are cancelled, a higher weight reduction benefit is obtained. To make up for the insufficient stiffness and strength in the blade body region of the blade caused by the large cavity structure, a hybrid reinforcement of metal wire + high-modulus carbon fiber is used to reinforce the stiffness of the hollow region, and a hollow fan blade with uniform stiffness distribution is obtained. The hollow fan blade of this structure has a more excellent weight reduction advantage while ensuring that the fan blade has sufficient strength and modulus, especially for small-sized engine fan blades, the weight reduction advantage is more obvious. The hollow fan blade of this structure cancels the variable-thickness core plate of the traditional corrugated hollow fan blade, and the structure is relatively simple. It has very important engineering application value for weight reduction and efficiency increase of advanced aero-engines.

[0061] In some embodiments, as Figure 1 — Figure 2As shown, the hollow-structured fan blade is formed by welding two whole plates of the blade back 1 and the blade basin 2 respectively. Since the corrugated structure of the traditional titanium alloy hollow blade is no longer used, the core plate is cancelled, and the three-layer structure of the traditional corrugated cavity is simplified to a two-layer structure.

[0062] In some embodiments, as Figure 1 shown, at least some other carbon fiber hybrid reinforcements 8 among the multiple carbon fiber hybrid reinforcements are connected between the blade tip 3 and the leading edge 5 or the trailing edge 6 of the hollow-structured fan blade, that is, connected between the blade tip 3 and the leading edge 5 of the hollow-structured fan blade, or connected between the blade tip 3 and the trailing edge 6 of the hollow-structured fan blade. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: The carbon fiber hybrid reinforcement can cover the internal cavity of the hollow-structured fan blade, so as to better enhance the overall strength of the internal cavity of the hollow-structured fan blade.

[0063] In some embodiments, as Figure 3A — Figure 5 shown, the internal cavity 7 of the hollow-structured fan blade includes a plurality of sub-cavities arranged in a "mouth" or "pin" shape matrix. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: It can enhance the overall rigidity of the hollow-structured fan blade.

[0064] In some embodiments, as Figure 3A — Figure 5 shown, the inner sides of the blade back and the blade basin panels are pre-processed with inner cavities (sub-cavities) in the shape of "mouth" or "pin" according to the size and load-bearing characteristics of the blade, and the inner cavities are smoothed and polished.

[0065] In some embodiments, as Figure 6 — Figure 7 shown, the twist of the carbon fiber 10 is 18 - 25 turns per meter. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through the appropriate twist of the carbon fiber, it is ensured that the carbon fiber can provide sufficient stiffness performance and protect the carbon fiber, and can better enhance the overall strength of the internal cavity of the hollow-structured fan blade.

[0066] In some embodiments, as Figure 6 — Figure 7 shown, the carbon fiber 10 is preliminarily infiltrated with epoxy resin. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through the appropriate carbon fiber infiltration process, it can better enhance the overall strength of the internal cavity of the hollow-structured fan blade.

[0067] More preferably, as Figure 6 — Figure 7As shown, the carbon fiber 10 is preliminarily infiltrated with an epoxy resin solution having a concentration not higher than 15%. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through a more suitable carbon fiber infiltration process, better overall reinforcement of the internal cavity of the hollow-structured fan blade can be achieved.

[0068] In some embodiments, as Figure 6 — Figure 7 shown, the metal wire 9 is a titanium alloy wire. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through the central metal wire of the carbon fiber hybrid reinforcement of a suitable material (the titanium alloy wire has high toughness and low yield strength), better overall reinforcement of the internal cavity of the hollow-structured fan blade can be achieved.

[0069] In some embodiments, as Figure 6 — Figure 7 shown, the diameter of the metal wire 9 is 0.5 to 1.5 mm. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through the central metal wire of the carbon fiber hybrid reinforcement of a suitable diameter, better overall reinforcement of the internal cavity of the hollow-structured fan blade can be achieved.

[0070] In some embodiments, as Figure 6 — Figure 7 shown, a region of 3 to 5 mm is reserved at both ends of the metal wire 9, and there is no carbon fiber in this region.

[0071] In some embodiments, as Figure 1 — Figure 9 shown, at least some of the carbon fiber hybrid reinforcements 8 among the multiple carbon fiber hybrid reinforcements are connected between the blade tip 3 and the blade root 4 by atomic diffusion, that is, they are connected to the top of the blade back 1 and the blade basin 2, and the bottom of the blade back 1 and the blade basin 2 respectively by atomic diffusion. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable connection process of the carbon fiber hybrid reinforcement, better overall reinforcement of the internal cavity of the hollow-structured fan blade can be achieved.

[0072] In some embodiments, the multiple carbon fiber hybrid reinforcements 8 are arranged in multiple parallel planes. According to the above technical solution, the hollow-structured fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable arrangement method of the carbon fiber hybrid reinforcement, better overall reinforcement of the internal cavity of the hollow-structured fan blade can be achieved.

[0073] In some embodiments, when multiple carbon fiber hybrid reinforcements 8 are arranged in multiple parallel planes, the carbon fiber hybrid reinforcements 8 in two adjacent parallel planes are staggered with each other. According to the above technical solution, the hollow structure fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable arrangement method of the carbon fiber hybrid reinforcements, the internal cavity of the hollow structure fan blade can be better integrally reinforced.

[0074] In some embodiments, as Figure 1 — Figure 9 shown, the number of carbon fiber hybrid reinforcements 8 per unit area (which can also be referred to as "arrangement density") is 40 - 60 per square decimeter. Since the cross-sectional area of the hollow structure fan blade is usually about 4000 square millimeters (i.e., 0.4 square decimeters), for the hollow structure fan blade with this usual cross-sectional area, about 16 - 24 carbon fiber hybrid reinforcements 8 are arranged. According to the above technical solution, the hollow structure fan blade of the present invention can achieve the following beneficial technical effects: Through a suitable arrangement density of the carbon fiber hybrid reinforcements, the internal cavity of the hollow structure fan blade can be better integrally reinforced.

[0075] More preferably, the number of carbon fiber hybrid reinforcements 8 per unit area is 50 per square decimeter. Therefore, for the hollow structure fan blade with this usual cross-sectional area, about 20 carbon fiber hybrid reinforcements 8 are arranged. According to the above technical solution, the hollow structure fan blade of the present invention can achieve the following beneficial technical effects: Through a more suitable arrangement density of the carbon fiber hybrid reinforcements, the internal cavity of the hollow structure fan blade can be better integrally reinforced.

[0076] According to an embodiment of the present invention, a turbofan engine includes the hollow structure fan blade as described in any of the foregoing aspects. According to the above technical solution, the turbofan engine of the present invention can achieve the following beneficial technical effects: The internal hollow structure of the fan blade is simple and has an obvious weight reduction advantage.

[0077] The specific embodiments of the present invention have been described above, but those skilled in the art will understand that the above specific embodiments do not constitute a limitation to the present invention. Those skilled in the art can make various modifications based on the above disclosed content without exceeding the scope of the present invention.

Claims

1. A hollow-structured fan blade, characterized in that, the hollow-structured fan blade includes a blade back and a blade bowl, wherein the blade back and the blade bowl are respectively connected together at the blade tip and the blade root of the hollow-structured fan blade, thereby defining an internal cavity; the hollow-structured fan blade further includes a plurality of carbon fiber hybrid reinforcements disposed in the internal cavity, and at least some of the plurality of carbon fiber hybrid reinforcements are connected between the blade tip and the blade root to integrally reinforce the internal cavity of the hollow-structured fan blade; wherein each of the plurality of carbon fiber hybrid reinforcements includes a metal wire at the center and carbon fibers twisted with the metal wire as the central axis.

2. The hollow-structured fan blade according to claim 1, characterized in that, at least some of the plurality of carbon fiber hybrid reinforcements are connected between the blade tip and the leading edge or the trailing edge of the hollow-structured fan blade.

3. The hollow-structured fan blade according to claim 1, characterized in that, the internal cavity of the hollow-structured fan blade includes a plurality of sub-cavities arranged in a "mouth" or "pin" shaped matrix.

4. The hollow-structured fan blade according to claim 1, characterized in that, the twist of the carbon fiber is 18 - 25 twists per meter.

5. The hollow-structured fan blade according to claim 1, characterized in that, the carbon fiber is preliminarily infiltrated with epoxy resin.

6. The hollow-structured fan blade according to claim 1, characterized in that, the metal wire is a titanium alloy wire.

7. The hollow-structured fan blade according to claim 1, characterized in that, at least some of the plurality of carbon fiber hybrid reinforcements are connected between the blade tip and the blade root by atomic diffusion.

8. The hollow-structured fan blade according to claim 1, characterized in that, the plurality of carbon fiber hybrid reinforcements are arranged in a plurality of parallel planes.

9. The hollow-structured fan blade according to claim 1, characterized in that, the number of carbon fiber hybrid reinforcements per unit area is 40 - 60 per square decimeter.

10. A turbofan engine, characterized in that, it includes the hollow-structured fan blade according to any one of the foregoing claims.

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