Axial layered polar woven ceramic matrix composite turbine rotor blade disc structure

Abstract

The invention discloses an axial layered polar woven ceramic matrix composite turbine rotor blade disc structure, which is characterized in that a fiber prefabricated body bearing framework is formed by axially staggering and laminating a plurality of layers of two-dimensional polar woven single-layer prefabricated bodies, and each layer of two-dimensional polar woven single-layer prefabricated body comprises radial radial yarns, circumferential equidistant concentric yarns and radial additional yarns; the radial yarns radially extend outwards with the center of the blade disc as the center, the outer ends of the radial yarns form a blade body laying layer, the circumferential equidistant concentric yarns are arranged in an equidistant concentric annulus mode with the center of the blade disc as the center, and the circumferential equidistant concentric yarns and the radial yarns are orthogonally interspersed. The radial yarn is arranged in a radius area where the gap between adjacent radial yarns is enlarged to a gap threshold value, is led out to the edge of the blade disc along the radial middle position, and is interspersed with the circumferential equidistant concentric yarns in an anti-phase plain weaving manner. According to the CMCs bladed disc, the fiber reinforcement effect can be better achieved, and especially in the radial direction and the circumferential direction, the mechanical property of the CMCs bladed disc is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aero-engine structure design, and relates to an axial layered polar woven ceramic matrix composite turbine rotor blisk structure. Background Art

[0002] An aero-engine is the culmination of the industrial design and manufacturing field, directly determining the performance and design ceiling of an aircraft. Among them, the turbine rotor, as a core component, is the main power source of the engine. Generally speaking, the higher the inlet gas temperature before the turbine, the greater the unit thrust generated by the engine, and the better the overall performance of the whole machine. High-performance materials and structures have become the key bottleneck factors restricting the improvement of engine performance, and new design solutions are urgently needed to meet the future development needs.

[0003] Ceramic matrix composites (CMCs) have the comprehensive advantages of light weight, high temperature resistance, high modulus, and corrosion resistance, and can work reliably under higher temperature and high-speed conditions. In addition, abandoning the integral blisk design with tenon grooves in the structure can effectively achieve the weight reduction goal and avoid installation extrusion and contact stress, reducing fretting wear. Therefore, the CMCs integral blisk structure that combines the advantages of both has great potential in improving the overall performance of the turbine or engine.

[0004] However, at present, there has been no breakthrough in the research on CMCs blisk design at home and abroad. Since the 1990s, although there have been individual CMCs blisk cases for experiments, their designs are mainly based on the trial-and-error method of process experience and experimental verification, lacking a structural design scheme and analysis method that comprehensively consider the blisk structure process and load-bearing characteristics.

[0005] The manufacturing and forming process of the CMC structure is essentially different from that of the metal structure, and it is necessary to clarify the mesoscopic preform structure and macroscopic ply organization scheme in the design stage. The existing conventional CMCs integral blisk schemes are mainly based on the yarn arrangement design in the rectangular coordinate system, and are cut and formed after overall deposition, which will cause significant and extensive yarn discontinuity, significantly reducing the mechanical properties of the relevant areas. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an axial layered polar woven ceramic matrix composite turbine rotor blisk structure in view of the above-mentioned existing deficiencies. The main body of the preform of this structure is formed by the circumferentially equidistant concentric yarns and multiple bundles of radially radiating yarns intertwined, which can effectively ensure the continuity of the yarns, and thus improve the ability of the structure to bear centrifugal loads. At the large radius of the disk, the patent designs radial yarn addition to cope with the uneven disk strength caused by the expansion of the radial yarn gaps. Axially, a two-dimensional preform staggered laminated structure is adopted, and the radially radiating yarns and the circumferentially equidistant concentric yarns form a polar weave through orthogonal interpenetration. The process requirements are simple, which is convenient for the deposition of the blisk matrix and the construction of the blade profile. The blade structure in this structure can be directly obtained by extending and cutting the radially radiating yarns, and the overall blisk configuration is realized with as little yarn torsion as possible. The circumferentially equidistant concentric yarns at the disk edge are stacked radially along the blade profile to form an integrated structure of the blade shell - disk edge for reinforcement. This patent provides a feasible solution for the design of CMCs integral blisks.

[0007] To achieve the above technical objectives, the technical solutions adopted by the present invention are as follows: An axial layered polar woven ceramic matrix composite turbine rotor blisk structure, the turbine rotor blisk structure includes a blisk and blades arranged on the outer peripheral surface of the blisk. Both the blisk and the blades of the turbine rotor blisk structure are composed of a fiber preform load-bearing skeleton and a matrix. The matrix is deposited on the surface of the fiber preform load-bearing skeleton. The fiber preform load-bearing skeleton is axially staggered and laminated by several layers of two-dimensional polar woven single-layer preforms. Each layer of two-dimensional polar woven single-layer preform includes radially radiating yarns, circumferentially equidistant concentric yarns, and radial yarn addition. The number of radially radiating yarns is several. The radially radiating yarns radiate outward with the center of the blisk as the center, and the outer ends form the main body ply of the blade. The number of circumferentially equidistant concentric yarns is several, and they are arranged in an equidistant concentric circular ring manner with the center of the blisk. The circumferentially equidistant concentric yarns and the radially radiating yarns are orthogonally interpenetrated. The radial yarn addition is arranged in the radius region where the gap between adjacent radially radiating yarns expands to the gap threshold, and is led out from the radial middle position to the disk edge of the blisk, and is interpenetrated with the circumferentially equidistant concentric yarns by an inverse plain weave method.

[0008] To optimize the above technical solutions, the specific measures taken also include: The above-mentioned fiber preform load-bearing skeleton further includes an integrated structure of the shell - disk edge. The integrated structure of the shell - disk edge is formed by bending the circumferential yarns stacked 3 - 5 layers radially near the disk edge, and includes a shell part covering the blade body and a disk edge part extending to the front and rear edges of the disk. The bending part is transitioned by an arc with a radius of ≥3 times the yarn diameter.

[0009] The above-mentioned matrix is deposited on the surface of the fiber preform load-bearing skeleton by chemical vapor infiltration or precursor infiltration and pyrolysis process.

[0010] The adjacent two-dimensional polar braided single-layer preforms are stacked with misalignment around the axis of the blisk, and the difference in the deflection angle between adjacent layers does not exceed ±2°. The axial projection deflection angle of the radial yarns is adapted to the near-equal strength distribution of the blade cross-section.

[0011] The above-mentioned radial yarn addition is carried out by 2.5D braiding between the circumferentially equidistant and concentric yarns of the two-dimensional polar braided single-layer preforms in different layers to strengthen the axial load-bearing capacity of the fiber preform load-bearing skeleton.

[0012] The transition section between the above-mentioned shell part and the disk rim part extends axially to the front and rear edges of the disk at the blade root, and layer-by-layer stitching is realized through the Z-direction needling process.

[0013] The above-mentioned shell part adopts a smooth transition with a circular arc curved surface at the blade tip turning, and the fillet radius R = 1.5 - 2 mm.

[0014] The middle part of the above-mentioned blisk has a shaft hole, and the fiber preform load-bearing skeleton in the area near the shaft hole is 3D braided, and the fiber volume fraction is 40% ± 5%.

[0015] The above-mentioned matrix adopts a gradient sintering process at the shell-disk rim interface, the temperature gradient is 50 °C / cm, and the final porosity < 3%.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention adopts a polar braided structure in which equidistant and concentric circumferential yarns and radial yarns are orthogonally interspersed. The obtained braided structure naturally conforms to the shape of the blisk, greatly reducing the discontinuous area of the main yarns caused by the processing technology, and ensuring the overall mechanical properties of the blisk. Compared with other common forms of braiding methods, it can better play the fiber reinforcement role, especially in the radial and circumferential directions, and significantly improve the mechanical properties of the CMCs blisk.

[0017] 2. The present invention realizes the overall blisk design of the braided structure through axial layering. Each polar braided single-layer preform rotates around the axis with misalignment according to the blade profile, and the radial yarns are directly extended to form the blade body. The complex mating structure and related accessories of the split type are omitted, the form is simple, and the braiding feasibility is high. On the basis of meeting the use strength, it can greatly reduce the mass of the blisk, reduce stress concentration, reduce fretting wear, and avoid installation extrusion and contact stress. Compared with the traditional casting or additive manufacturing process, this structural design can make more effective use of the anisotropy of CMCs materials and improve the mechanical properties in the main load-bearing direction.

[0018] 3. In the present invention, a yarn addition structure is arranged between adjacent radial yarns of the blisk, effectively solving the problem of uneven load capacity distribution caused by the sparse density of radial yarns at the large radius of the disk, and strengthening the overall radial performance of the disk.

[0019] 4. In the present invention, a braided structure integrating the blade shell sleeve and the disk rim is designed by arranging circumferential yarns near the disk rim. This design makes the yarn braiding more conform to the aerodynamic shape of the blade, connects the disk rim and the blade, and improves the ability of the local high-stress area to bear circumferential loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the external structure of the axial layered polar braided ceramic matrix composite turbine rotor disk structure of the present invention; Figure 2 It is a schematic diagram of the turbine rotor disk structure of the present invention after removing the matrix; Figure 3 It is a schematic diagram of the structure of a single-layer two-dimensional polar braided fiber preform; Figure 4 It is a schematic diagram of the structure of the shell sleeve - disk rim integrated structure; The reference numerals are: the fiber preform load-bearing skeleton 1, the two-dimensional polar braided single-layer preform 1a, the shell sleeve - disk rim integrated structure 1b, the radially radiating yarn 11, the circumferentially equidistant concentric yarn 12, the radially added yarn 13, the matrix 2, the shell sleeve part 31, and the disk rim part 32. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be described and explained below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0022] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. In addition, it can also be understood that although the efforts made in this development process may be complex and time-consuming, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacturing or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood that the content disclosed in the present application is insufficient.

[0023] References to "embodiments" in this application mean that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive of other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.

[0024] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the ordinary meaning as understood by those of ordinary skill in the technical field to which this application belongs. The words such as "a", "an", "one", "the" and the like involved in this application do not indicate a limitation in quantity and can mean singular or plural. The terms "comprising", "including", "having" and any variations thereof involved in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device that includes a series of steps or units (units) is not limited to the listed steps or units, but may further include steps or units not listed, or may further include other steps or units inherent to these processes, methods, products or devices. The words such as "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "plurality" / "several" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates an "or" relationship between the associated objects before and after. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0025] The axial layered polar woven ceramic matrix composite turbine rotor disk structure of this embodiment is composed of an axial two-dimensional polar woven fiber preform 1 and a disk matrix 2. The preform can be divided into a polar woven preform disk main body 1a and a shell sleeve - disk edge integrated structure 1b, as Figure 1-2 shown.

[0026] In the embodiment, the roulette and the blade body adopt an integrated polar weaving method. The radial yarns mainly bear the radial centrifugal stress of the blade and the disc body, and the circumferentially equally spaced concentric yarns 12 bear the circumferential stress of the roulette. The roulette is composed of radially arranged radial yarns 11 and circumferentially equally spaced concentric yarns 12 that are orthogonally interlaced. The main ply structure of the blade body is directly formed by the radial yarns of each two-dimensional polar weaving single-layer preform 1a after being stacked in a staggered manner around the axis. Compared with other forms of weaving structures, the continuity of the yarns is ensured as much as possible, which is beneficial for the blade to bear the centrifugal load. The thickness of the single-layer two-dimensional polar weaving single-layer preform 1a is small, which is convenient for the dense stacking of the main structure of the blisk preform. However, due to the installation angle of the blade, it is difficult for this structure to meet the arrangement of the blade plies according to the blade profile, and there is a risk of circumferential interlayer dislocation under the aerodynamic load. Therefore, a circumferential ply structure stacked radially is adopted at the disc edge, and a continuous blade shell sleeve integrated with the disc edge is formed along the circumferential direction of the disc edge through the blade basin and the blade back, realizing the three-dimensional reinforcement of the blade plies with reference to the blade profile. At the same time, the blade shell sleeve is stacked by plies to form an airfoil envelope surface with aerodynamic profile characteristics, enhancing the aerodynamic load-bearing capacity of the blade.

[0027] In the embodiment, the staggered stacking of the two-dimensional polar weaving single-layer preform 1a should meet the following requirements: at the same radius from the disc center, the circumferentially equally spaced concentric yarns 12 of each layer are completely coincident in the axial projection of the engine, and the projection of the radially arranged radial yarns 11 forms an angular difference in the axial direction due to the staggered design. Among them, the interlayer deflection angle should be optimized according to the near-equal strength criterion of the blade cross-section, so that the extension section of the radially arranged radial yarns 11 can meet the airfoil camber characteristics without large deflection or torsion. In the specific implementation of the stagger angle, it is recommended that the difference in the deflection angle does not exceed ±2°, so as to avoid the reduction of the structural load-bearing capacity caused by the concentration of pore defects and ensure the uniformity of the axial load of the fiber skeleton after the matrix deposition. Under the condition of meeting the service strength, this structure is relatively simple, convenient for processing, and can greatly reduce the weight of the blisk.

[0028] The blisk weaving main body is arranged radially as Figure 3The radial added yarn 13 shown is specifically a yarn introduced radially between adjacent radial radial yarns 11, starting from the middle of the blade disk and ending at the edge of the disk. The starting point of the radial added yarn 13 should be located at half of the angle between two adjacent radial radial yarns 11 in the circumferential direction. It is recommended to select a position where the gap between adjacent radial radial yarns 11 is twice the minimum gap in the radial direction, thereby ensuring the uniformity of the radial yarn distribution and avoiding the radial bearing capacity of the wheel disk from decreasing with the radius. The radial added yarn 13 and the circumferentially equidistant concentric yarns 12 are woven in an anti-phase orthogonal manner. When the process allows, twill weaving and a 2.5D interlayer interlacing structure can be used to improve the axial strength of the design and reduce the risk of delamination failure of the blade disk structure. The turbine disk is generally a hollow disk. In the wheel disc weaving structure, axial holes should be reserved around the disk center according to the overall design. Since the processing of the axial holes will cut the radial yarns, the mating parts need to be strengthened. Therefore, the axial hole area of ​​the blade disk can be reinforced by local 3D weaving to moderately increase the fiber volume fraction and compensate for the weakening of strength caused by the inevitable cutting of radial fibers during processing.

[0029] The shell-plate rim integrated structure 1b is composed of a shell portion 31 and a plate rim portion 32. Figure 4 As shown, the circumferentially equidistant concentric yarns 12 of the wheel disc should be radially stacked in 3-5 layers near the edge of the disc, and a dense layer is formed by polar weaving and special compaction as the main body of the disc edge part 32. The disc edge part 32 extends axially to the front and rear edges of the wheel disc at the transition section of the blade root, and the interlayer suture reinforcement is achieved through the needle punching process; the circumferentially equidistant concentric yarns 12 are bent nearly 90° from the blade basin to the back of the blade to form a shell part 31 covering the cross section of the blade body. This structure should meet the aerodynamic characteristics design requirements of the blade. The transition section bends with an arc transition with a radius greater than 3 times the yarn diameter to reduce fiber damage and stress concentration. The tip turning point is smoothed with an annular small radius arc surface to avoid local stress concentration. Under the premise of meeting the aerodynamic shape requirements of the blade body as much as possible, the interlayer deflection angle design of similar size should be met as much as possible, which is conducive to the formation of a more uniform pore distribution in the structure after deposition, and avoids the reduction of structural bearing capacity caused by the concentration of pore defects.

[0030] The matrix is ​​densified by chemical vapor infiltration (CVI) after the fiber skeleton is woven and formed, and the high stress area is further strengthened by precursor impregnation pyrolysis (PIP). During the sintering process, it is recommended to use gradient sintering for the shell-disk edge interface to ensure that the porosity of the transition section meets the design requirements.

[0031] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. An axially layered polar braided ceramic matrix composite turbine rotor blade disk structure, the turbine rotor blade disk structure comprising a blade disk and blades arranged on the outer peripheral surface of the blade disk, the blade disk and blades of the turbine rotor blade disk structure are both composed of a fiber preform load-bearing skeleton (1) and a matrix (2), the matrix (2) being deposited on the surface of the fiber preform load-bearing skeleton (1), and characterized in that: The fiber preform load-bearing skeleton (1) is composed of a plurality of layers of two-dimensional polar woven single-layer preforms (1a) stacked axially staggered, each layer of the two-dimensional polar woven single-layer preform (1a) comprising radial radial yarns (11), circumferentially equidistant concentric yarns (12) and radial added yarns (13), the number of the radial radial yarns (11) being a plurality, the radial radial yarns (11) radiating outwards from the center of the blade disk and the outer ends forming the main blades. The body ply, the number of the circumferentially equidistant concentric yarns (12) is several, and they are arranged in the form of equidistant concentric rings at the center of the blade disk. The circumferentially equidistant concentric yarns (12) are orthogonally interlaced with the radial radial yarns (11). The radial added yarns (13) are arranged in the radius area where the gap between adjacent radial radial yarns (11) is expanded to the gap threshold, and are led out to the edge of the blade disk along the radial middle position, and are interlaced with the circumferentially equidistant concentric yarns (12) in an inverse plain weave manner.

2. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 1 is characterized by: The fiber preform load-bearing skeleton (1) also includes a shell-disk edge integrated structure (1b), which is formed by bending 3-5 layers of circumferential yarns stacked radially near the disk edge, and includes a shell portion (31) covering the blade body and a disk edge portion (32) extending to the front and rear edges of the wheel disk, and the bending portion adopts an arc transition of ≥3 times the yarn diameter.

3. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 1 is characterized by: The matrix (2) is deposited on the surface of the fiber preform load-bearing skeleton (1) through chemical vapor infiltration or precursor impregnation and cracking technology.

4. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 2 is characterized by: Adjacent two-dimensional polar braided single-layer preforms (1a) are stacked in an offset manner around the blade disk axis, the difference in deflection angles between adjacent layers does not exceed ±2°, and the axial projection deflection angle of the radial radial yarns (11) is adapted to the nearly equal strength distribution of the blade section.

5. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 2 is characterized by: The radial added yarn (13) is 2.5D woven between the circumferentially equidistant concentric yarns (12) of different layers of two-dimensional polar woven single-layer preforms (1a) to strengthen the axial bearing capacity of the fiber preform load-bearing skeleton (1).

6. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 2 is characterized by: The transition section between the shell part (31) and the disc edge part (32) extends axially at the blade root to the front and rear edges of the wheel disc, and interlayer suturing is achieved through a Z-direction needling process.

7. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 2 is characterized by: The shell part (31) adopts an annular arc surface for smooth transition at the turning point of the blade tip, and the fillet radius R is 1.5-2mm.

8. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 2 is characterized by: The blade disk has an axial hole in the middle, and the fiber preform load-bearing skeleton (1) in the vicinity of the axial hole is 3D woven, with a fiber volume fraction of 40%±5%.

9. The axially layered polar braided ceramic matrix composite turbine rotor blade disk structure according to claim 2 is characterized by: The matrix (2) adopts a gradient sintering process at the shell-disk edge interface, with a temperature gradient of 50° C. / cm and a final porosity of <3%.

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