Ceramic matrix composite turbine blade double-tenon connecting structure

Abstract

The invention provides a ceramic matrix composite turbine blade double-tenon connecting structure, and belongs to the technical field of aero-engines, the ceramic matrix composite turbine blade double-tenon connecting structure comprises a ceramic matrix composite blade, and the ceramic matrix composite blade is provided with a blade crown and an inner tenon; the split outer tenon is made of metal materials and is divided into a left tenon body and a right tenon body in the circumferential direction of the engine, a hollow structure is arranged between the left tenon body and the right tenon body, the shape of the hollow structure is matched with that of the inner tenon body, and the split outer tenon body is the same as that of a tenon body of a turbine blade made of the metal materials in structure. Compared with a turbine blade made of a high-temperature alloy material, the CMC turbine blade double-tenon connecting structure has the advantages that the cold air consumption can be reduced, the whole machine performance can be improved, meanwhile, the thrust-weight ratio of an engine can be increased, in-situ reloading with a metal material blade is achieved, turbine structure changes caused by application of a ceramic matrix composite material can be reduced to the maximum extent, and the service life of the turbine blade is prolonged. And the design and manufacturing cost is greatly reduced.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a double tenon connection structure for ceramic matrix composite turbine blades. Background Technology

[0002] With the continuous improvement of aero-engine performance, turbine inlet temperatures are constantly increasing. Engines with a thrust-to-weight ratio of 15-20 have turbine inlet temperatures reaching as high as 2300K, far exceeding the temperature resistance of even the most advanced high-temperature alloys. To address this issue, turbine blades require advanced cooling design and coating technologies to reduce surface temperatures. Previous turbine blade cooling design technologies primarily focused on high-pressure turbines. However, in recent years, with the rising turbine inlet temperatures, the cooling requirements for low-pressure turbine blades have become increasingly prominent, necessitating a greater volume of cooling air. Yet, to improve engine performance, the distribution of cooling air to hot-end components is reduced. This contradiction, besides requiring the development of more advanced cooling technologies, urgently necessitates the use of a new lightweight, high-temperature resistant material. This is both a necessity for improving engine performance and a key to increasing the engine's thrust-to-weight ratio.

[0003] Therefore, ceramic matrix composites (CMCs) have seen rapid development in recent years, driving their application in aero-engines. Among them, SiC / SiC composites, due to their high tensile strength, creep resistance, high temperature resistance, oxidation resistance, and good compatibility with ceramic matrices, have broad application prospects in aerospace, shipbuilding, and nuclear industries. Without air cooling and thermal barrier coatings, CMC materials can operate at temperatures 150°C to 350°C higher than nickel-based superalloys, with a potential operating temperature of up to 1650°C. Furthermore, their density is only 1 / 3 to 1 / 4 that of superalloys. Studies have shown that using CMC-SiC in hot-end components such as combustion chambers, turbines, afterburners, and nozzles can increase engine operating temperatures by 300°C to 500°C, reduce structural weight by 50% to 70%, increase thrust by 30% to 100%, and reduce cooling gas consumption by more than 30%. It is considered an ideal material for high-performance aero-engine hot-end components.

[0004] The application of CMC materials in aero-engines started relatively late, especially in rotor components, where it is still in the exploratory stage. Mainstream aero-engine low-pressure turbine blades still use nickel-based superalloys or single-crystal materials. Typical metallic low-pressure turbine blade structures include... Figure 1 and Figure 2As shown, the blade body 11 is formed by precision casting without any allowance, the tenon 12 is fir-shaped, the blade crown 13 is a serrated crown, and the internal structure is arranged with baffles, baffle columns and other structures for cooling and heat exchange. The blade surface is coated with a thermal barrier coating for heat insulation. In high-temperature areas, such as the leading edge and trailing edge areas, structures such as film cooling holes 14 and slotted exhaust windows 15 are arranged for cooling.

[0005] However, high-temperature alloys have limited temperature resistance, and the large amount of cooling air required for turbine blades will reduce the engine's working capacity. In addition, the turbine blades made of high-temperature alloys have complex structures, making structural design difficult. High-temperature alloys have high density, resulting in heavy blades and large centrifugal loads, which is not conducive to improving the engine's thrust-to-weight ratio. Furthermore, if ceramic matrix composite turbine blades are designed according to the structure of metal turbine blades, it is extremely difficult to use a one-piece molding process for all structures. Moreover, it is extremely difficult to replace ceramic matrix composite turbine blades with metal turbine disks in situ, requiring adaptive modifications to the turbine blades, turbine disks, and other structures. Summary of the Invention

[0006] The purpose of this application is to provide a double tenon connection structure for ceramic matrix composite turbine blades to solve or alleviate at least one of the problems in the prior art.

[0007] The technical solution of this application is: a double-tenon connection structure for ceramic matrix composite turbine blades, comprising:

[0008] A ceramic matrix composite blade, the blade having a crown and an inner tenon;

[0009] The metal material has a split external tenon, which is divided into a left tenon and a right tenon along the circumferential direction of the engine. The space between the left tenon and the right tenon is a hollow structure. The shape of the hollow structure is adapted to the inner tenon. The configuration of the split external tenon is the same as that of the tenon of the metal material turbine blade.

[0010] In at least one embodiment of this application, the inner tenon configuration is a dovetail shape.

[0011] In at least one embodiment of this application, the tenon configuration of the metal turbine blades is the same, including fir tree shape and dovetail shape.

[0012] In at least one embodiment of this application, the split outer tenon is made of a high-temperature alloy material or a single-crystal high-temperature alloy material.

[0013] In at least one embodiment of this application, the split outer tenon is manufactured using a precision casting process with no allowance.

[0014] In at least one embodiment of this application, the inner tenon of the blade, the extension root connecting the inner tenon, and the blade body are integrally formed into a preform by three-dimensional weaving of ceramic matrix composite material. The fibers of the ceramic matrix composite material are woven from the bottom of the inner tenon along the blade height direction, and the thickness of the preform is varied by changing the thickness of the weft yarn in areas with drastic thickness changes.

[0015] In at least one embodiment of this application, a “T”-shaped leaf crown base is formed by turning the fiber cloth of the blade tip pressure surface and the blade tip suction surface outward to both sides, and then the leaf crown thickness is increased by a lay-up process to form a leaf crown preform.

[0016] Under the same temperature conditions, the CMC turbine blades provided in this application reduce the cooling gas consumption from 2.3% to 0% compared to turbine blades made of high-temperature alloy materials, resulting in a 100% reduction in cooling gas consumption and improved overall engine performance. At the same time, the density of ceramic matrix composite materials is only 1 / 4 to 1 / 3 of that of high-temperature alloy materials, reducing the blade weight by 30% to 50%, which can improve the engine thrust-to-weight ratio. It can also achieve in-situ replacement with metal blades, minimizing the turbine structure modifications caused by the application of ceramic matrix composite materials and significantly reducing design and manufacturing costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0018] Figure 1 This is a front view of the working blade structure of a low-pressure turbine made of high-temperature alloy material.

[0019] Figure 2 This is a side view of the working blade structure of a low-pressure turbine made of high-temperature alloy material.

[0020] Figure 3 This is a schematic diagram of the double tenon connection structure of the ceramic matrix composite turbine blade of this application.

[0021] Figure 4 This is a schematic diagram of the blade prefabricated structure in this application.

[0022] Figure 5 This is a schematic diagram of the leaf crown prefabricated structure in this application. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0024] In order to improve the temperature resistance of turbine blades, reduce the amount of cooling air used in the engine, reduce the weight of the blades, improve the overall performance of the engine, and realize the in-situ replacement of ceramic matrix composite low-pressure turbine working blades with metal blades, this application provides a double tenon connection structure for ceramic matrix composite (CMC) turbine blades.

[0025] like Figure 3 As shown, the CMC turbine blade double tenon connection structure 20 provided in this application includes: a blade 21 made of CMC material and a split outer tenon 24 made of metal material. The blade 21 has a solid blade body, with a crown 22 at the radially outer tip and an inner tenon 23 at the radially inner root. The split outer tenon 24 is consistent with the edge plate and tenon structure of existing metal material air-cooled low-pressure turbine blade designs, retaining the fir tree-shaped tenon structure of existing metal material turbine blade designs. Therefore, the split outer tenon 24 is also a fir tree-shaped structure, divided into left and right parts along the engine circumference—a left tenon and a right tenon. The space between the two parts is designed as a hollow structure, with the shape of the hollow structure being the same as the shape of the inner tenon 23 and the root extension section of the CMC material. In this application, the inner tenon 23 of the CMC material is a dovetail tenon, which is enclosed inside the split outer tenon 24 of the metal material. The split outer tenon 24 is connected and fixed on the turbine disk, thereby realizing the in-situ installation replacement of the CMC turbine blade with the existing metal turbine blade.

[0026] The ceramic matrix composite (CMC) turbine blade double tenon connection structure of this application achieves the installation and fixation of turbine blades made of two materials by setting an inner tenon 23 of CMC material and a split outer tenon 24 of metal material to form a double tenon joint.

[0027] In some embodiments of this application, the split outer tenon 24 can be made of high-temperature alloy material, such as nickel-based high-temperature alloy or cobalt-based high-temperature alloy, or it can be made of single-crystal high-temperature alloy material.

[0028] Furthermore, the split tenon 24 of the metal material in this application is manufactured by precision casting without allowance, so that the split tenon 24 of the metal material and the blade 21 of the CMC material can achieve precise connection and fit.

[0029] In this application, the ceramic matrix composite preform of the blade 21 is manufactured using a three-dimensional integrated weaving and lay-up molding process. To ensure blade strength and fiber integrity, the inner tenon, extension root, and blade preform of the ceramic matrix composite are integrally molded using a three-dimensional weaving process. The fibers are woven from the bottom of the inner tenon 23 along the blade height. For areas with significant thickness variations—such as the inner tenon—the thickness of the inner tenon preform is varied by changing the weft yarn thickness, aiming to simultaneously meet the requirements of varying thickness and yarn continuity. The structure of the inner tenon preform is as follows: Figure 4 As shown. Further, for the crown 22 of the CMC material blade 21, the fiber cloth on the pressure surface and suction surface of the blade tip is turned outwards to both sides to form a "T"-shaped structure of the crown base. Then, the crown thickness is increased through a lay-up process to form a crown preform, as shown. Figure 5 As shown.

[0030] Under the same temperature conditions, the CMC turbine blades provided in this application reduce the amount of cooling air from 2.3% to 0% compared with turbine blades made of high-temperature alloy materials, resulting in a 100% reduction in cooling air consumption and improved overall engine performance. At the same time, the density of ceramic matrix composite materials is only 1 / 4 to 1 / 3 of that of high-temperature alloy materials, reducing the blade weight by 30% to 50% and improving the engine's thrust-to-weight ratio.

[0031] The ceramic matrix composite turbine blades of this application can typically be used as working blades (rotor blades) of low-pressure turbines. They achieve double tenon joint fixation through a double tenon structure, which can realize in-situ replacement with metal blades. This can minimize the turbine structure modification caused by the application of ceramic matrix composites and greatly reduce design and manufacturing costs.

[0032] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A double-tenon connection structure for a ceramic matrix composite turbine blade, characterized in that, include: A ceramic matrix composite blade (21) having a crown (22) and an inner tenon (23); The metal material split external tenon (24) is divided into a left tenon and a right tenon along the circumferential direction of the engine. The left tenon and the right tenon are hollow. The shape of the hollow structure is adapted to the inner tenon (23). The configuration of the split external tenon (24) is the same as the tenon configuration of the metal material turbine blade.

2. The double-tenon connection structure for ceramic matrix composite turbine blades as described in claim 1, characterized in that, The inner tenon (23) has a dovetail shape.

3. The double-tenon connection structure for ceramic matrix composite turbine blades as described in claim 1, characterized in that, The tenon configurations of the metal turbine blades are the same, including fir tree shape and swallowtail shape.

4. The double tenon connection structure for ceramic matrix composite turbine blades as described in claim 3, characterized in that, The split external tenon (24) is made of high-temperature alloy material or single-crystal high-temperature alloy material.

5. The double-tenon connection structure for ceramic matrix composite turbine blades as described in claim 4, characterized in that, The split external tenon (24) is manufactured using a precision casting process with no allowance.

6. The double-tenon connection structure for ceramic matrix composite turbine blades as described in claim 1, characterized in that, The inner tenon (23) of the blade (21), the extension root connecting the inner tenon (23) and the blade body are integrally formed by three-dimensional weaving of ceramic matrix composite material to form a preform. The fibers of the ceramic matrix composite material are woven from the bottom of the inner tenon (23) along the blade height direction, and the thickness of the preform is varied by changing the thickness of the weft yarn in areas where the thickness changes drastically.

7. The double tenon connection structure for ceramic matrix composite turbine blades as described in claim 6, characterized in that, The fiber cloth on the blade tip pressure surface and the blade tip suction surface is turned outward to both sides to form a "T" shaped blade crown base. Then, the thickness of the blade crown is increased by the lay-up process to form a blade crown preform.

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