A CMC turbine outer ring assembly having axial high thermal match and method of making

Abstract

The present application relates to the technical field of ceramic matrix composite turbine components, and discloses a CMC turbine outer ring assembly with axial high thermal matching and a preparation method, which adopts an axially segmented CMC turbine outer ring, uses a seal to act as a'seal + axial track', and realizes sealing of the splicing joint between the first outer ring base body and the second outer ring base body and the splicing joint between the adjacent two arc-shaped sections through the seal, while the first outer ring base body and the second outer ring base body are guided by the seal to expand or shrink along the axial direction freely when the CMC turbine outer ring bears a temperature load, so as to adapt to the deformation of the middle layer casing, coordinate the thermal deformation difference between the CMC turbine outer ring and the metal component middle layer casing, release the axial thermal stress of the turbine outer ring assembly, and moreover, the seal limits the first outer ring base body and the second outer ring base body to only have relative displacement in the axial direction, prevents radial and circumferential dislocation, and ensures the integrity and centring of the CMC turbine outer ring.

Description

Technical Field

[0001] This invention relates to the field of ceramic matrix composite turbine components, and discloses a CMC turbine outer ring assembly with high axial thermal matching and its preparation method. Background Technology

[0002] As the core power unit of modern aircraft, the performance and reliability of aero engines directly affect flight safety, fuel efficiency, and environmental adaptability. With the aviation industry's increasing demands for high thrust-to-weight ratio, low emissions, and long-life engines, turbine inlet temperatures are continuously rising, placing extremely high demands on the high-temperature resistance of turbine components. Ceramic matrix composites (CMCs), due to their excellent high-temperature strength, low density, and good creep resistance, have become an ideal material for manufacturing turbine outer rings, and are expected to replace traditional nickel-based superalloys, achieving the dual goals of weight reduction and temperature increase.

[0003] However, the CMC material and the metal materials used in the intermediate casing (such as nickel-based superalloys) differ significantly in their thermophysical properties, especially in their coefficients of thermal expansion. During engine start-up, shutdown, and operation under varying conditions, the metal connecting structures, such as the metal intermediate casing, undergo significant thermal deformation due to temperature changes. The CMC turbine outer ring has a low coefficient of thermal expansion, resulting in less deformation than the metal intermediate casing. This leads to a significant deformation mismatch between the CMC turbine outer ring and the metal intermediate casing. This mismatch introduces excessive additional constraint stress on the CMC turbine outer ring, easily causing cracking or loss of the CMC material. It may also cause the clearance control between the outer ring and the rotor blade tip to fail, affecting engine efficiency and safety.

[0004] In existing technologies, flexible supports are typically installed between the outer ring of the CMC turbine and the metal casing to partially alleviate thermal stress. However, this often increases structural complexity and weight, and fails to fundamentally solve the problem of in-plane constraint stress caused by circumferential deformation mismatch. Summary of the Invention

[0005] The purpose of this invention is to provide a CMC turbine outer ring assembly with high axial thermal compatibility and its manufacturing method, which can solve the problem of significant deformation incompatibility between the CMC turbine outer ring and the metal component middle casing.

[0006] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0007] A CMC turbine outer ring assembly with high axial thermal matching includes: The CMC turbine outer ring includes a first outer ring base and a second outer ring base arranged coaxially. The cross-sectional shape of the first outer ring base and the second outer ring base is an L-shaped structure. The first outer ring base and the second outer ring base are spliced ​​together to form a ring with a U-shaped cross-section. The middle casing has a first mounting edge and a second mounting edge on its axial sides, and the middle casing is connected to the first outer ring base through the first mounting edge and the middle casing is connected to the second outer ring base through the second mounting edge. The first sealing piece is coaxially disposed between the first outer ring substrate and the second outer ring substrate, and is used to seal the circumferential splice seam between the first outer ring substrate and the second outer ring substrate.

[0008] Furthermore, both the first outer ring substrate and the second outer ring substrate are composed of multiple arc-shaped segments spliced ​​together. In the circumferential direction, a second sealing plate is provided between two adjacent arc-shaped segments. The second sealing plate is connected to the first sealing plate and is used for the axial splicing seam between two adjacent arc-shaped segments.

[0009] Furthermore, both the first sealing sheet and the second sealing sheet include at least a heat insulation layer and a load-bearing layer.

[0010] Furthermore, the middle casing and the outer ring of the CMC turbine together form an annular cold air chamber; and the middle casing is provided with a cold air inlet hole for guiding cold air into the annular cold air chamber; The axial arc plate is provided with a cooling channel. The air inlet of the cooling channel is connected to the annular cold air cavity. The air outlet of the cooling channel is located on the outer wall of the concave side of the axial arc plate. It is used to guide the cold air in the annular cold air cavity to the outer wall of the concave side of the axial arc plate to cool the axial arc plate and form an air film cooling layer on the outer wall of the concave side of the axial arc plate.

[0011] Furthermore, both the first outer ring base and the second outer ring base include a vertical plate and an axial arc plate. The axial arc plate is connected to the vertical plate to form an L-shaped structure. The vertical plate is connected to the mounting edge of the middle casing. The splicing end face of the axial arc plate is provided with a sealing groove for installing the sealing component.

[0012] Furthermore, the middle casing is also provided with an arc-shaped cover plate; the first mounting edge and the second mounting edge are respectively connected to the two sides of the arc-shaped cover plate, and W-shaped elastic sealing rings are provided between the first mounting edge and the vertical plate of the first outer ring base, and between the second mounting edge and the vertical plate of the second outer ring base, and the cold air inlet hole is provided on the first mounting edge.

[0013] Furthermore, a first limiting boss, a second limiting boss, and a third limiting boss are provided on both the first and second mounting edges. The first limiting boss abuts against the circumferential wall of the vertical plate, and the second and third limiting bosses abut against the side of the vertical plate.

[0014] A method for fabricating a CMC turbine outer ring assembly with high axial thermal matching, comprising the following steps: The first outer ring matrix preform and the second outer ring matrix preform are prepared and densified, and then assembled with the sealing component to obtain the CMC turbine outer ring; The CMC turbine outer ring is assembled with the middle casing and the W-type elastic sealing ring to obtain the CMC turbine outer ring assembly.

[0015] Furthermore, the steps for preparing the first outer ring matrix preform and the second outer ring matrix preform include: Several layers of fiber cloth or fiber strips are laid on the lower mold to form an axial arc-shaped plate preform; Several layers of fiber cloth or fiber strips are laid on the upper mold to form the outer preform; Install the cooling channel forming embedded part on the lower mold, and make the lower end of the cooling channel forming embedded part penetrate the axial arc plate preform; The lower mold is closed with the upper mold, and the upper end of the cooling channel forming embedded part penetrates the outer preform. Then the axial arc plate preform is sewn to the outer preform to form the first outer ring base preform and the second outer ring base preform containing the cooling channel forming embedded part.

[0016] Furthermore, after obtaining the first outer ring matrix preform and the second outer ring matrix preform, the first outer ring matrix preform and the second outer ring matrix preform are densified, and then the cooling channel forming embedded part is removed in a directional manner to obtain the first outer ring matrix and the second outer ring matrix.

[0017] Compared with the prior art, the beneficial effects of this invention are: This invention employs an axially segmented CMC turbine outer ring, utilizing a sealing element as both a "sealant and an axial track." The joints between the first and second outer ring bases, as well as the joints between adjacent arc segments, are sealed using the sealing element. Simultaneously, when the CMC turbine outer ring is subjected to temperature loads, the first and second outer ring bases expand or contract freely axially under the guidance of the sealing element to accommodate the deformation of the middle casing, coordinating the thermal deformation difference between the CMC turbine outer ring and the metal component middle casing, and releasing the axial thermal stress of the turbine outer ring assembly. Furthermore, the sealing element restricts the first and second outer ring bases to relative displacement only in the axial direction, preventing radial and circumferential misalignment, thus ensuring the integrity and alignment of the CMC turbine outer ring. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the CMC turbine outer ring assembly with high axial thermal matching in the embodiment; Figure 2 This is a cross-sectional view of the CMC turbine outer ring assembly in the embodiment; Figure 3 This is a schematic diagram of the CMC turbine outer ring structure in the embodiment; Figure 4 This is a schematic diagram of the structure of the first outer ring matrix and the second outer ring matrix in the embodiment; Figure 5 This is a schematic diagram of the sealing component in the embodiment; Figure 6 This is a schematic diagram of the middle casing in the embodiment; Figure 7 This is a schematic diagram of the upper mold in the embodiment; Figure 8 This is a schematic diagram of the lower mold in the embodiment; Figure 9 This is a schematic diagram of the cooling channel positioning plate assembly in the embodiment; Figure 10 This is a schematic diagram of the structure of the first outer ring matrix preform or the second outer ring matrix preform in the embodiment; Figure 11 This is a flowchart illustrating the method for fabricating a CMC turbine outer ring assembly with high axial thermal matching in this embodiment; Among them, 1-middle casing, 11-first mounting edge, 12-arc-shaped cover plate, 13-second mounting edge, 14-first limiting boss, 15-second limiting boss, 16-third limiting boss, 2-CMC turbine outer ring, 21-first outer ring base, 22-second outer ring base, 23-arc segment, 24-vertical plate, 25-axial arc plate, 26-first sealing groove, 27-second sealing groove, 28-cooling channel, 3-cold air cavity, 5-W-type elastic sealing ring, 6-sealing component, 61-load-bearing layer, 62-heat insulation layer, 63-first sealing plate, 64- - Second sealing plate, 701- Axial arc-shaped plate preform, 702- Outer preform, 801- Lower mold, 8011- Radial lower stitching hole of preform, 8012- Mold positioning groove, 8013- Lower positioning hole of embedded part, 802- Upper mold, 8021- Left sub-mold, 8022- Right sub-mold, 8023- Radial upper stitching hole of preform, 8024- Axial upper stitching hole of preform, 901- Cooling channel forming embedded part, 904- Cooling channel positioning plate, 9041- Positioning block, 9042- Fixing hole, 909- Cooling channel positioning plate assembly. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0020] See Figures 1 to 10 The present invention provides a CMC turbine outer ring assembly with high axial thermal matching, comprising: CMC turbine outer ring 2, the CMC turbine outer ring 2 includes a first outer ring base 21 and a second outer ring base 22 arranged coaxially. The cross-sectional shape of the first outer ring base 21 and the second outer ring base 22 is an L-shaped structure. The first outer ring base 21 and the second outer ring base 22 are spliced ​​together to form a ring with a U-shaped cross-section. The middle casing 1 has a first mounting edge 11 and a second mounting edge 13 on its axial sides respectively. The middle casing 1 is connected to the first outer ring base 21 through the first mounting edge 11, and the middle casing 1 is connected to the second outer ring base 22 through the second mounting edge 13. The first sealing piece 63 is coaxially disposed between the first outer ring base 21 and the second outer ring base 22, and is used to seal the circumferential splice seam between the first outer ring base 21 and the second outer ring base 22.

[0021] This invention employs an axially segmented CMC turbine outer ring 2, utilizing a first sealing plate 63 as a "sealant + axial track." The splice seam between the first outer ring base 21 and the second outer ring base 22, as well as the splice seam between two adjacent arc segments, are sealed by the first sealing plate 63. Simultaneously, when the CMC turbine outer ring 2 is subjected to temperature loads, the first outer ring base 21 and the second outer ring base 22 freely expand or contract axially under the guidance of the first sealing plate 63 to adapt to the deformation of the middle casing 1, coordinate the thermal deformation difference between the CMC turbine outer ring 2 and the metal component middle casing, and realize the release of axial thermal stress in the turbine outer ring assembly. Moreover, the first sealing plate 63 restricts the first outer ring base 21 and the second outer ring base 22 to only undergo relative displacement in the axial direction, preventing radial and circumferential misalignment, thereby ensuring the integrity and alignment of the CMC turbine outer ring 2.

[0022] Example This embodiment further elaborates on the CMC turbine outer ring assembly with high axial thermal matching and its preparation method, as detailed below.

[0023] The CMC turbine outer ring assembly with high axial thermal matching includes a CMC turbine outer ring 2 and a middle casing 1.

[0024] See Figures 1 to 3The CMC turbine outer ring 2 includes a first outer ring base 21, a second outer ring base 22, and a sealing element 6. The first outer ring base 21 and the second outer ring base 22 are coaxially arranged. Both the first outer ring base 21 and the second outer ring base 22 are L-shaped circular ring structures, and both the first outer ring base 21 and the second outer ring base 22 are composed of multiple arc segments 23 spliced ​​together.

[0025] See Figure 3 and Figure 4 Each arc segment 23 of the first outer ring base 21 and each arc segment 23 of the second outer ring base 22 includes a vertical plate 24 and an axial arc plate 25. One side of the axial arc plate 25 is connected to the vertical plate 24 to form an L-shaped structure, and the other side of the axial arc plate 25 is a circumferential splicing end face, which is provided with a first sealing groove 26. The end faces at both ends of the axial arc plate 25 are axial splicing end faces, which are provided with a second sealing groove 27. The first sealing groove 26 and the second sealing groove 27 are both used to install sealing components 6. Multiple arc segments 23 are spliced ​​into a circle to form the first outer ring base 21 and the second outer ring base 22. The first outer ring base 21 and the second outer ring base 22 are spliced ​​to form the CMC turbine outer ring 2, and the ring formed by splicing the axial arc plates 25 serves as the engine gas flow channel.

[0026] In this embodiment, the radius of curvature of the axial arc plate 25 is matched with the turbine blade tip clearance, and the inner arc surface is coated with a 0.1~0.3mm thick environmental barrier coating. The materials of the vertical plate 24 and the axial arc plate 25 are SiC / SiC composite materials.

[0027] See Figure 5The sealing component 6 includes a first sealing plate 63 and a second sealing plate 64. Two second sealing plates 64 are provided and connected to both ends of the first sealing plate 63, forming an overall I-shaped structure. The sealing component 6 is made of a dual-material composite. Specifically, the sealing component 6 includes a heat insulation layer 62 and a load-bearing layer 61, both of which adopt an I-shaped structure. The lower heat insulation layer 62 is made of heat-resistant aluminum silicate fiber-reinforced silicate composite material, used to block the heat flow from the engine combustion passage from entering the CMC turbine outer ring assembly. The upper load-bearing layer 61 is made of surface-treated GH3536 high-temperature alloy, used to provide connection rigidity for the splicing of the first outer ring substrate 21 and the second outer ring substrate 22. During installation, one arc segment 23 corresponds to one sealing element 6. Then, the first sealing piece 63 is embedded into the first sealing groove 26 of the first outer ring base 21, and the second sealing piece 64 is embedded into the second sealing groove 27. Next, the first sealing piece 63 and the second sealing piece 64 are respectively embedded into the first sealing groove 26 and the second sealing groove 27 of the second outer ring base 22. Thus, the first outer ring base 21 is spliced ​​with the second outer ring base 22 through the sealing element 6. In the spliced ​​arc segment 23, the first sealing piece 63 seals the circumferential splicing seam along the arc segment 23, while the second sealing piece 64 is reserved at the end of the arc segment 23. When multiple arc segments 23 are spliced, the second sealing piece 64 seals the splicing seam between adjacent arc segments 23.

[0028] It should be noted that the first sealing piece 63 is arc-shaped, and its curvature is consistent with that of the first sealing groove 26. The cross-sectional shape of the first sealing piece 63 can be S-curve or wavy, etc., to adapt to different thermal expansion scenarios. Moreover, on a single arc segment 23, after the second sealing piece 64 at one end is inserted into the second sealing groove 27, half of the width of the second sealing piece 64 is exposed outside the second sealing groove 27, so as to facilitate insertion into the sealing groove of the adjacent arc segment 23; the second sealing piece 64 at the other end is inserted into the second sealing groove 27, and the second sealing groove 27 also has a groove depth of half the width of the second sealing piece 64, so that the sealing pieces of the adjacent arc segment 23 can be inserted, thus achieving the sealing of the splice between adjacent arc segments 23. It should be noted that the heat insulation layer 62 and the load-bearing layer 61 can also be stacked as a whole and then installed in the corresponding sealing groove. In this case, only one sealing groove needs to be set.

[0029] In this embodiment, the first sealing piece 63 of the sealing member 6 is arc-shaped, and its arc curvature matches the first sealing groove 26 of the first outer ring base 21 and the second outer ring base 22. The width direction of the first sealing piece 63 is consistent with the axial direction of the CMC turbine outer ring 2. Half of the width of the first sealing piece 63 is inserted into the first sealing groove 26 of the first outer ring base 21, and the other half of the width of the first sealing piece 63 is inserted into the first sealing groove 26 of the second outer ring base 22. At the same time, the two second sealing pieces 64 are simultaneously embedded in the second sealing groove 27 at the ends of the first outer ring base 21 and the second outer ring base 22. When the engine operates and generates high-temperature loads, a thermal deformation difference occurs between the CMC turbine outer ring 2 and the middle casing 1. The first outer ring base 21 and the second outer ring base 22 exhibit expansion or contraction tendencies. At this time, the first sealing plate 63 and the second sealing plate 64 together act as axial tracks, providing axial displacement guidance for the two outer ring bases. This ensures that the thermal deformation displacement is strictly released along the turbine outer ring axial direction to accommodate the deformation of the middle casing 1 and eliminate axial thermal stress in the outer ring assembly. Simultaneously, the I-shaped sealing member 6 forms a radial rigid constraint on the first outer ring base 21 and the second outer ring base 22, and forms an interlocking structure in the circumferential direction of the turbine outer ring. Meanwhile, the load-bearing layer 61 is made of GH3536 high-temperature alloy, which has sufficient connection rigidity to resist radial shear force and circumferential shear force, so as to prevent the two outer ring bases from being offset relative to each other along the radial direction of the turbine outer ring, avoid radial misalignment from damaging the roundness and sealing of the gas flow channel, and prevent the two outer ring bases from being offset relative to each other along the circumferential direction of the turbine outer ring, so as to ensure the circumferential integrity and centering of the multiple arc segments 23 after being spliced ​​into a whole ring.

[0030] See Figures 1 to 6 The middle casing 1 includes a first mounting edge 11, an arc-shaped cover plate 12, and a second mounting edge 13. The first mounting edge 11 and the second mounting edge 13 are respectively connected to both sides of the arc-shaped cover plate 12, and the middle casing 1 has an overall U-shaped structure. During assembly, the first mounting edge 11 is fastened to the vertical plate 24 of the first outer ring base 21 by bolts and nuts, and the second mounting edge 13 is fastened to the vertical plate 24 of the second outer ring base 22 by bolts and nuts. Furthermore, W-shaped elastic sealing rings 5 ​​are provided between the first mounting edge 11 and the vertical plate 24 of the first outer ring base 21, and between the second mounting edge 13 and the vertical plate 24 of the second outer ring base 22 to seal the gap between the middle casing 1 and the CMC turbine outer ring 2, thereby forming a cold air chamber 3. It should be noted that a cold air inlet hole is provided on the first mounting edge 11 to guide cold air into the cold air chamber 3.

[0031] Further, see Figure 6A first limiting boss 14, a second limiting boss 15, and a third limiting boss 16 are provided on the outer wall surfaces of the first mounting edge 11 and the second mounting edge 13. The first limiting boss 14 abuts against the circumferential wall surface of the vertical plate 24, and the second limiting boss 15 and the third limiting boss 16 abut against the side surface of the vertical plate 24. The first limiting boss 14, the second limiting boss 15, and the third limiting boss 16 contact the vertical plate 24 to position the relative position between the middle casing 1 and the CMC turbine outer ring 2, and form a line contact seal. Moreover, a W-type elastic sealing ring 5 is installed between the second limiting boss 15 and the third limiting boss 16.

[0032] Further, see Figure 4 The first outer ring base 21 and the second outer ring base 22 each have a plurality of cooling channels 28 on their axial arc plates 25. These channels guide the cold air from the cold air chamber 3 to the concave outer wall of the axial arc plate 25. As the cold air flows along the cooling channels 28, heat exchange is achieved through convection, thereby cooling the axial arc plate 25. Simultaneously, after the cold air exits the cooling channels 28, a film cooling layer is formed on the concave side wall of the axial arc plate 25, achieving film cooling and preventing the high-temperature combustion gases from the engine combustion channels from directly impacting the axial arc plate 25, thus improving cooling efficiency. Moreover, the flow resistance of each cooling channel 28 on the axial arc plate 25 is different, with the cooling channel 28 near the leading edge of the turbine outer ring having the lowest flow resistance. The cross-section of the cooling channels 28 can be circular, elliptical, rectangular, or other shapes, and the size, circumferential number, and axial arrangement of the cooling channels 28 can be adjusted to optimize the distribution of cold air, achieving precise distribution of cold air and ensuring a uniform temperature field on the turbine outer ring.

[0033] It should be noted that the first outer ring base 21 and the second outer ring base 22 are also provided with sealing cooling holes to guide the cold air in the cold air chamber 3 to the first sealing groove 26 and the second sealing groove 27 to cool the sealing part 6 of the I-beam structure.

[0034] Based on the same inventive concept, see [link to inventive concept] Figure 11 This embodiment also provides a method for preparing a CMC turbine outer ring assembly with high axial thermal matching. When preparing the CMC turbine outer ring 2, a preform forming mold is required. The preform forming mold is divided into an upper mold 802, a lower mold 801, a cooling channel forming embedded part 901, and a cooling channel positioning plate 904.

[0035] See Figure 8 The lower mold 801 has an arc plate-shaped structure with mold positioning grooves 8012 on both sides. Several radially downward stitching holes 8011 for preforms and several lower positioning holes 8013 for embedded parts are opened through the lower mold 801. The radially downward stitching holes 8011 for preforms and the lower positioning holes 8013 for embedded parts do not overlap.

[0036] See Figure 7 The upper mold 802 includes a left sub-mold 8021 and a right sub-mold 8022. Both the left sub-mold 8021 and the right sub-mold 8022 are provided with a plurality of radially upward stitching holes 8023 and axially upward stitching holes 8024 of the preform and a plurality of positioning holes on the pre-embedded parts for forming cooling channels. The positions of the radially upward stitching holes 8023 of the preform in the upper mold 802 and the radially downward stitching holes 8011 of the preform in the lower mold 801 correspond one-to-one.

[0037] See Figure 9 The cooling channel forming embedded part 901 is used to form the cooling channel 28 during the preparation of the CMC turbine outer ring 2. The cooling channel forming embedded part 901 has the same shape, size, and arrangement as the cooling channel 28. The cooling channel forming embedded part 901 is made of a material that can achieve directional ablation. In this embodiment, the cooling channel forming embedded part 901 is made of Al2O3. Al2O3 has a melting point of 2050℃ and will not react during the CVI-PIP densification process.

[0038] See Figure 9 The cooling channel positioning plate 904 is used to accurately position the cooling channel forming pre-embedded part 901 on the lower mold 801. The cooling channel positioning plate 904 is provided with fixing holes 9042 for positioning the cooling channel forming pre-embedded part 901. The cooling channel forming pre-embedded part 901 is inserted into the fixing holes 9042 without loosening or falling out, forming the cooling channel positioning plate assembly 909. Moreover, the cooling channel positioning plate 904 is provided with a positioning block 9041, which cooperates with the mold positioning groove 8012 of the lower mold 801 to achieve positioning and ensure that the cooling channel forming pre-embedded part 901 can be accurately inserted into the pre-embedded part lower positioning hole 8013 of the lower mold 801.

[0039] In this embodiment, the CMC turbine outer ring assembly fabrication method includes the following steps: Step 1: Lay several layers of fiber cloth or fiber strips on the lower mold 801 to form an axial arc-shaped plate preform 701.

[0040] Step 2: Assemble the cooling channel forming embedded part 901 and the cooling channel positioning plate 904 into a cooling channel positioning plate assembly 909. Then, assemble the cooling channel positioning plate assembly 909 with the lower mold 801 containing the axial arc plate preform 701. The positioning block 9041 of the cooling channel positioning plate is inserted into the mold positioning groove 8012 of the lower mold 801. After the lower end of the cooling channel forming embedded part 901 pierces through the axial arc plate preform 701, it is inserted into the embedded part lower positioning hole 8013 of the lower mold 801 and fixed on the lower mold 801. During the process of the cooling channel forming embedded part 901 piercing through the axial arc plate preform 701, the fiber position of the axial arc plate preform 701 undergoes slight movement in a local position, providing space for the cooling channel forming embedded part 901 without disrupting the fiber continuity.

[0041] Step 3: Lay several layers of fiber cloth or fiber strips on the surface of the left sub-mold 8021 and the right sub-mold 8022 to form the outer preform 702, which includes two L-shaped structures on the left and right sides.

[0042] Step 4: Remove the cooling channel positioning plate 904, close the upper mold 802 and the lower mold 801, and at the same time, make the upper end of the cooling channel forming embedded part 901 penetrate the outer preform and pass through the positioning hole on the cooling channel forming embedded part of the upper mold 802. When closing the mold, the upper mold 802 and the lower mold 801 are positioned and fixed by matching the positioning pin and the mold positioning groove 8012 of the lower mold 801.

[0043] Step 5: Along the radial stitching holes 8023 and 8011 of the preform in the upper mold 802, radially stitch the axial arc plate preform and the outer preform assembly. Along the axial stitching holes 8024 of the preform in the upper mold 802, axially stitch the assembly. Repeat steps one to five to form the first outer ring base preform and the second outer ring base preform, which contain a cooling channel forming embedded part 901, such as... Figure 10 As shown. It should be noted that the first outer ring matrix preform and the second outer ring matrix preform have the same structure, so only one set of molds is required.

[0044] Step Six: Densify the first and second outer ring matrix preforms using a CVI-PIP process to obtain the first outer ring matrix 21 and the second outer ring matrix 22. Specifically, the first and second outer ring matrix preforms are immersed in a directional removal liquid, causing the pre-embedded cooling channel forming pre-part 901 to react and dissolve with the directional removal liquid. After all the cooling channel forming pre-part 901 is dissolved and removed, the required cooling channels 28 are formed within the first and second outer ring matrices 21 and 22. Finally, the first and second outer ring matrices 21 and 22 with the internal cooling channels 28 are removed. The directional removal liquid is molten NaOH at a temperature not exceeding 800°C. It should be noted that those skilled in the art can use other densification processes as needed.

[0045] Step 7: The first outer ring base 21 and the second outer ring base 22 are spliced ​​together using the sealing component 6 to form the CMC turbine outer ring 2. Then, the CMC turbine outer ring 2 is assembled with the middle casing 1 and the W-type elastic sealing ring 5 to obtain the CMC turbine outer ring assembly.

[0046] Compared with the prior art, the CMC turbine outer ring assembly with high axial thermal matching and its manufacturing method of the present invention have the following significant advantages: This invention, by designing a cooling channel 28 inside the CMC turbine outer ring 2, can achieve targeted cooling of key areas such as the leading edge of the turbine outer ring and the sealing element 6, optimize the cooling airflow efficiency, reduce the maximum operating temperature of the CMC turbine outer ring 2 and improve the temperature field uniformity, suppress thermal stress and interlayer delamination risks, and improve the overall service temperature of the hot end of the turbine outer ring and the sealing element.

[0047] This invention employs an axially segmented CMC turbine outer ring 2 comprising a first outer ring base 21 and a second outer ring base 22, achieving the core functions of "flexible decoupling and axial constraint," fundamentally solving the problem of thermal deformation incoordination. Existing integral CMC turbine outer ring 2 suffers from deformation incoordination with the metal casing. This incoordination generates significant internal stress. While simple segmentation can release some stress, the lack of connection and guidance can lead to radial and axial misalignment of the outer ring segment under airflow, compromising gas stability and blade tip clearance. In this invention, the I-shaped sealing element 6 acts as an "axial track," allowing the first and second outer ring bases to freely expand or contract axially under its guidance to accommodate the thermal deformation of the middle casing 1, thus releasing axial thermal stress. Simultaneously, the sealing element 6 restricts the first and second outer ring bases 21 and 22 to relative displacement only along the axial direction, preventing radial and circumferential misalignment and ensuring the integrity and alignment of the turbine outer ring.

[0048] The middle casing 1 of the present invention is provided with a first limiting boss 14, a second limiting boss 15 and a third limiting boss 16 on the side plate, which can realize the positioning of the middle casing 1 and the CMC turbine outer ring 2 and enhance the gas sealing of the side plate. At the same time, a W-shaped elastic sealing ring 5 is placed between the CMC turbine outer ring 2 and the side plate of the metal middle casing 1. The W-shaped elastic sealing ring 5 is placed between the second limiting boss 15 and the third limiting boss 16, which enhances the sealing between the CMC turbine outer ring 2 and the side plate of the metal middle casing 1. It can also compensate for the thermal expansion difference between the CMC turbine outer ring 2 and the metal middle casing 1, and improve the stability and reliability of the outer ring assembly structure under thermal cycling.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A CMC turbine outer ring assembly with high axial thermal matching, characterized in that, include: CMC turbine outer ring (2), the CMC turbine outer ring (2) includes a first outer ring base (21) and a second outer ring base (22) arranged coaxially. The cross-sectional shape of the first outer ring base (21) and the second outer ring base (22) is an L-shaped structure. The first outer ring base (21) and the second outer ring base (22) are spliced ​​to form a U-shaped ring. The middle casing (1) has a first mounting edge (11) and a second mounting edge (13) on its axial sides respectively. The middle casing (1) is connected to the first outer ring base (21) through the first mounting edge (11), and the middle casing (1) is connected to the second outer ring base (22) through the second mounting edge (13). The first sealing piece (63) is coaxially disposed between the first outer ring base (21) and the second outer ring base (22) to seal the circumferential splice seam between the first outer ring base (21) and the second outer ring base (22).

2. The CMC turbine outer ring assembly according to claim 1, characterized in that, The first outer ring substrate (21) and the second outer ring substrate (22) are both composed of multiple arc segments (23) spliced ​​together. In the circumferential direction, a second sealing plate (64) is provided between two adjacent arc segments (23). The second sealing plate (64) is connected to the first sealing plate (63). The second sealing plate (64) is used for the splicing seam between two adjacent arc segments (23) along the axial direction.

3. The CMC turbine outer ring assembly according to claim 2, characterized in that, Both the first sealing sheet (63) and the second sealing sheet (64) include at least a heat insulation layer (62) and a load-bearing layer (61).

4. The CMC turbine outer ring assembly according to claim 3, characterized in that, The middle casing (1) and the outer ring (2) of the CMC turbine together form an annular cold air chamber (3); and the middle casing (1) is provided with a cold air inlet hole for guiding cold air into the annular cold air chamber (3).

5. The CMC turbine outer ring assembly according to claim 4, characterized in that, Both the first outer ring base (21) and the second outer ring base (22) include a vertical plate (24) and an axial arc plate (25). The axial arc plate (25) is connected to the vertical plate (24) to form an L-shaped structure. The vertical plate (24) is connected to the mounting edge of the middle casing (1). The splicing end face of the axial arc plate (25) is provided with a sealing groove for installing the first sealing plate (63) and the second sealing plate (64). The inside of the axial arc plate (25) is provided with a cooling channel (28). The air inlet of the cooling channel (28) is connected to the annular cold air cavity (3). The air outlet of the cooling channel (28) is located on the concave outer wall of the axial arc plate (25) to guide the cold air in the annular cold air cavity (3) to the concave outer wall of the axial arc plate (25) to cool the axial arc plate (25) and form an air film cooling layer on the concave outer wall of the axial arc plate (25).

6. The CMC turbine outer ring assembly according to claim 5, characterized in that, The middle casing (1) is also provided with an arc-shaped cover plate (12); the first mounting edge (11) and the second mounting edge (13) are respectively connected to the two sides of the arc-shaped cover plate (12), and the first mounting edge (11) and the vertical plate (24) of the first outer ring base (21) and the second mounting edge (13) and the vertical plate (24) of the second outer ring base (22) are both provided with W-shaped elastic sealing rings (5), and the cold air inlet hole is provided on the first mounting edge (11).

7. The CMC turbine outer ring assembly according to claim 6, characterized in that, The first mounting edge (11) and the second mounting edge (13) are provided with a first limiting boss (14), a second limiting boss (15) and a third limiting boss (16). The first limiting boss (14) abuts against the circumferential wall of the vertical plate (24), and the second limiting boss (15) and the third limiting boss (16) abut against the side of the vertical plate (24).

8. A method for fabricating a CMC turbine outer ring assembly with high axial thermal matching, used to fabricate the CMC turbine outer ring assembly as described in any one of claims 1-7, characterized in that, Includes the following steps: The first outer ring matrix preform and the second outer ring matrix preform are prepared and densified, and then assembled with the sealing component (6) to obtain the CMC turbine outer ring (2); The CMC turbine outer ring (2) is assembled with the middle casing (1) and the W-type elastic sealing ring (5) to obtain the CMC turbine outer ring assembly.

9. The method for manufacturing the CMC turbine outer ring assembly according to claim 8, characterized in that, The steps for preparing the first outer ring matrix preform and the second outer ring matrix preform include: Several layers of fiber cloth or fiber strips are laid on the lower mold (801) to form an axial arc plate preform (701); Several layers of fiber cloth or fiber strips are laid on the upper mold (802) to form the outer preform (702); Install the cooling channel forming embedded part (901) on the lower mold (801) and make the lower end of the cooling channel forming embedded part (901) penetrate the axial arc plate preform (701). The lower mold (801) and the upper mold (802) are closed, and the upper end of the cooling channel forming embedded part (901) penetrates the outer preform (702). Then, the axial arc plate preform (701) is sewn to the outer preform (702) to form the first outer ring base preform and the second outer ring base preform containing the cooling channel forming embedded part (901).

10. The method for manufacturing the CMC turbine outer ring assembly according to claim 9, characterized in that, After the first outer ring matrix preform and the second outer ring matrix preform are made, the first outer ring matrix preform and the second outer ring matrix preform are densified, and then the cooling channel forming embedded part (901) is removed in a directional manner to obtain the first outer ring matrix (21) and the second outer ring matrix (22).

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