Ceramic matrix composite component air film hole layout structure considering coating falling

Abstract

The invention provides a ceramic matrix composite component air film hole layout structure considering coating shedding, a ceramic matrix composite component comprises a high temperature gradient area and a low temperature gradient area, a plurality of forward inclined expansion holes are distributed in the high temperature gradient area, and a plurality of circular air film holes are distributed in the low temperature gradient area; and the forward inclined expansion hole and the circular air film hole are formed in the base body. According to the self-adaptive air film hole pattern matching strategy of the coating stripping form, standard cylindrical holes are maintained and adopted in a non-stripping area of the coating, forward-inclined diffusion holes are formed in a gradient mode in an easy-stripping area of the coating, the cold air jet form is reconstructed through hole pattern combination, anisotropy of the ceramic-based composite material is considered, and the self-adaptive air film hole pattern matching strategy of the coating stripping form is obtained. The purposes of reducing the coating falling speed and maintaining and even improving the comprehensive cooling efficiency level of the surface of the component are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal protection and aerodynamic cooling of high-temperature components of aircraft engines, and relates to a multi-physics field coupled air film cooling structure for ceramic matrix composite components, and specifically to an air film hole layout structure for ceramic matrix composite components taking coating shedding into consideration. Background Art

[0002] As aircraft engine performance improves and combustion chamber temperatures rise, thermal protection technology for high-temperature components becomes increasingly critical. Thermal barrier coatings (TBCs), applied as functional coatings on turbine blade surfaces, utilize ceramic materials such as yttria-stabilized zirconia. These coatings can reduce the operating temperature of the blade substrate by 100-300K, effectively alleviating thermal stress and fatigue. Ceramic matrix composites (CMCs) are ideal materials for the hot-end components of new-generation aircraft engines due to their low density and high-temperature resistance. However, they are susceptible to oxidation, sulfidation, and water vapor reactions in high-temperature combustion gases. Environmental barrier coatings (EBCs) developed for this purpose protect the CMC substrate from corrosive gases while also providing thermal insulation. However, under extreme service conditions, TBCs / EBCs are subject to multiple damages, including high-temperature oxidative corrosion, mechanical erosion, and airflow scouring. Coupled with inherent coating defects, these coatings are prone to cracking and flaking under the coupled effects of thermal cycling and mechanical loads, exposing the substrate and significantly increasing the risk of failure.

[0003] Film cooling technology is another key means of protecting engine hot-end components. Film cooling involves injecting cold air into the main flow along a specific direction near the wall. Under the pressure and friction of the main flow, this cool air bends downstream and adheres to the wall, forming a cooler air film. This film isolates the wall from the hot gas and removes some of the radiant heat from the hot gas or bright flame, thereby effectively protecting the wall. However, traditional film hole layouts are typically designed for homogeneous materials and fail to consider the anisotropic thermal conductivity of ceramic matrix composites (CMCs). This can lead to high temperature gradients in the components and cause coating delamination. Directly transferring existing film hole layouts to CMCs presents the following problems: Because the impact of the CMC's anisotropic thermal conductivity on the temperature gradient within the CMC component and the overall film cooling effect is not considered, the temperature gradient within the CMC component is higher than that of traditional metal materials, accelerating coating delamination and exposing the CMC substrate directly to the hot gas, leading to CMC substrate failure. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide an air film hole layout structure for ceramic matrix composite components that takes into account coating shedding, so as to solve the technical problem in the existing technology that the CMC substrate is easily failed after the coating shedding due to excessive temperature gradient on the surface of the ceramic matrix composite component under harsh service environment of high temperature and high pressure.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A ceramic matrix composite component air film hole layout structure taking into account coating shedding, the air film hole layout structure is arranged on the ceramic matrix composite component; the ceramic matrix composite component includes a matrix 3 and a yarn 2, and the outer surface of the matrix 3 is coated with a coating 1; the ceramic matrix composite component includes a high temperature gradient area and a low temperature gradient area, the high temperature gradient area is provided with a plurality of forward-inclined expansion holes 4 to form a matrix structure, and the low temperature gradient area is provided with a plurality of circular air film holes 5 to form a matrix structure; the forward-inclined expansion holes 4 and the circular air film holes 5 are both inclined relative to the vertical direction and are both opened on the matrix 3.

[0007] The present invention also has the following technical features:

[0008] Specifically, the forward-inclined expansion hole 4 includes a first hole section 401 with a cylindrical structure and a second hole section 402 with an irregular platform structure.

[0009] Specifically, the diameter of the first hole section 401 is D.

[0010] Specifically, the top area of ​​the second hole segment 402 is the largest and the bottom area is the smallest; the top of the second hole segment 402 is an irregular hole, the maximum width of the top of the second hole segment in the transverse direction is 1.8D to 2.0D, and the maximum length of the top of the second hole segment in the longitudinal direction is L P The bottom end thereof is a circular hole, and the diameter of the bottom end hole is equal to the diameter D of the first hole section 401.

[0011] Specifically, the top of the second hole segment 402 is composed of two oppositely disposed curved edges 40201 of identical shapes and two long parallel straight edges 40202 of different lengths.

[0012] Specifically, the curved edge 40201 is composed of multiple arc edges, and the radii of the arc edges from front to back are 0.425D, 0.551D, 0.656D, 0.766D, 0.901D, 1.006D, 1.069D, 1.042D, 1.564D, 1.454D, 1.321D, 1.033D, 0.722D, 0.486D, and 0.313D respectively; the arc length of adjacent points of the front arc is 0.111D, and the arc length of adjacent points of the back arc is 0.152D.

[0013] Specifically, the lengths of the two straight edges 40202 are 0.35D to 0.45D and 0.9D to 1.5D respectively.

[0014] Specifically, the jet angle α of the forward-inclined expansion hole 4 is 45°, the forward-inclined angle β is 11°, and the spanwise expansion angle γ is 11°.

[0015] Specifically, the distance L between two adjacent forward-inclined expansion holes 4 in the longitudinal direction is M The distance L between two adjacent forward-inclined expansion holes 4 in the transverse direction is 6D to 7D. S The vertical distance from the top of the forward-inclined expansion hole 4 to the bottom surface of the ceramic matrix composite material component is 5D to 6D.

[0016] Specifically, the circular air film hole 5 is a cylindrical structure, and its diameter is equal to D.

[0017] Specifically, the jet angle α of the circular air film hole 5 is 45°.

[0018] Specifically, the distance between two adjacent circular air film holes 5 in the longitudinal direction is 6D to 7D, and the distance between two adjacent circular air film holes 5 in the transverse direction is 6D to 7D; the vertical distance from the top of the circular air film hole 5 to the bottom surface of the ceramic matrix composite component is 5D to 6D.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] (I) The present invention adopts an air film hole matching strategy that is adaptive to the coating peeling morphology. In the area where the coating is not easy to peel off, standard cylindrical holes are maintained, and forward-inclined diffusion holes are configured in a gradient manner in the area where the coating is easy to peel off. The cold air jet morphology is reconstructed by the hole combination, so as to achieve the purpose of slowing down the coating peeling speed while maintaining or even improving the comprehensive cooling efficiency level of the component surface.

[0021] (II) The present invention incorporates the cooling failure problem caused by coating peeling into the design framework of the air film hole layout, analyzes the complex coupling between the air film cooling performance and the coating damage factor, and fills the gap in the traditional design method that ignores the coating damage effect.

[0022] (III) The present invention addresses the anisotropic properties of CMC materials and proposes a solution for the layout of air film holes in ceramic matrix composite materials, thereby facilitating the development of a new generation of aircraft engines and ensuring the safe and efficient operation of aircraft engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The air film hole layout structure of Example 1 is shown. Figure 1 In the figure, (a) is a schematic diagram of the overall structure, and (b) is a schematic diagram of the parameter structure of the forward-inclined expansion hole.

[0024] Figure 2 Schematic diagram of the dimensional parameters of the top surface of the forward-inclined expansion hole.

[0025] Figure 3 The air film hole layout structure of comparative example 1 is shown.

[0026] Figure 4 The air film hole layout structure of comparative example 2 is shown.

[0027] Figure 5 The air film hole layout structure of comparative example 3 is shown.

[0028] Figure 6 The effects of different air film hole layout structures on the temperature gradient distribution of the ceramic matrix composite plate in Example 1 and Comparative Examples 1 to 3 are demonstrated.

[0029] Figure 7 for Figure 6 Quantization diagram of .

[0030] Figure 8 To demonstrate the effects of different air film hole layout structures on the cooling effect of the ceramic-based composite plate in Example 1 and Comparative Examples 1 to 3.

[0031] Figure 9 for Figure 8 Quantization diagram of .

[0032] The meanings of the symbols in the figure are: 1-coating, 2-yarn, 3-substrate, 4-forward-inclined expansion hole, 5-circular air film hole.

[0033] D-diameter of the first hole section, L W - the maximum spanwise distance of the second hole segment, α- the jet angle of the forward-inclined expansion hole, β- the forward-inclined expansion hole's forward angle, γ- the spanwise expansion angle of the forward-inclined expansion hole, L M -The distance between two adjacent forward-inclined expansion holes in the longitudinal direction, L S - the distance between two adjacent forward-inclined expansion holes in the transverse direction, h - the thickness of the ceramic matrix composite plate.

[0034] The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION

[0035] In this context, the term "high temperature gradient region" refers to the area of ​​the CMC component where the temperature gradient is greater than or equal to 1200K / m during operation. Coatings in this area are susceptible to shedding due to excessive temperature differences per unit distance. The term "low temperature gradient region" refers to the area of ​​the CMC component where the temperature gradient is less than or equal to 1200K / m during operation. The temperature differences per unit distance in this area are not significant, so coatings are also less susceptible to shedding.

[0036] It should be noted that, unless otherwise specified, all materials in the present invention are conventional materials known in the art.

[0037] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0038] Example 1 (matrix combination hole):

[0039] This embodiment provides a layout structure of air film holes for ceramic matrix composite components taking into account coating shedding. The layout structure of air film holes is arranged on the ceramic matrix composite plate; Figure 1 As shown, the ceramic-based composite plate includes a substrate 3 and yarn 2. The outer surface of the substrate 3 is coated with a coating 1. The ceramic-based composite plate includes a high temperature gradient region and a low temperature gradient region. The high temperature gradient region is provided with a plurality of forward-inclined expansion holes 4 forming a matrix structure, while the low temperature gradient region is provided with a plurality of circular air film holes 5 forming a matrix structure. Both the forward-inclined expansion holes 4 and the circular air film holes 5 are arranged obliquely relative to the vertical direction and are both provided on the substrate 3.

[0040] As a specific solution of this embodiment, the forward-inclined expansion hole 4 includes a first hole section 401 of a cylindrical structure and a second hole section 402 of an irregular platform structure; the diameter D of the first hole section 401 is 0.6 mm; the top area of ​​the second hole section 402 is the largest and the bottom area is the smallest, and its minimum aperture is equal to the diameter D of the first hole section 401, and the maximum span distance L W (i.e. the maximum width in the transverse direction) is 1.1832 mm (1.972D), and the maximum length in the longitudinal direction is L P It is 1.2906mm (2.151D).

[0041] As a specific solution of this embodiment, the jet angle α of the forward-inclined expansion hole 4 (i.e., the angle between the first hole section 401 and the horizontal plane) is 45°, the forward-inclined angle β (i.e., the angle between the axis of the first hole section 401 and the busbar of the second hole section 402 projected on the vertical plane) is 11°, and the spanwise expansion angle γ (i.e., the angle between the axis of the first hole section 401 and the busbar of the second hole section 402 projected on the horizontal plane) is 11°.

[0042] As a specific solution of this embodiment, the bottom end of the second hole segment 402 is a circular hole; the top end of the second hole segment 402 is an irregular hole (similar to the shape of a fan), which is composed of two oppositely arranged and completely identical curved edges 40201 and two long parallel straight edges 40202 oppositely arranged and different lengths.

[0043] As a specific solution of this embodiment, the lengths of the two straight edges 40202 are 0.2365 mm (0.394D) and 0.5831 mm (0.972D) respectively.

[0044] As a specific solution of this embodiment, the curved edge 40201 is composed of multiple arc edges, and the radii of the arc edges from front to back are 0.2547mm (0.425D), 0.3303mm (0.551D), 0.3934mm (0.656D), 0.4597mm (0.766D), 0.5403mm (0.901D), 0.6036mm (1.006D), 0.6411mm (1.069D), 0.6253mm (1.0 42D), 0.9383mm(1.564D), 0.8722mm(1.454D), 0.7925mm(1.321D), 0.6197mm(1.033D), 0.4331mm(0.722D), 0.2913mm(0.486D), 0.1878mm(0.313D), the length of adjacent points of the front arc is 0.0666mm(0.111D), and the length of adjacent points of the back arc is 0.091mm(0.152D).

[0045] As a specific solution of this embodiment, the distance L between two adjacent forward-inclined expansion holes 4 in the longitudinal direction is M The distance L between two adjacent forward expansion holes 4 in the transverse direction is 4 mm (6.67D). S the vertical distance from the top of the forward-inclined expansion hole 4 to the bottom surface of the ceramic-based composite plate (equal to the thickness h of the ceramic-based composite plate) is 3.25 mm (5.42D).

[0046] As a specific solution of this embodiment, the circular air film hole 5 is a cylindrical structure; the diameter of the circular air film hole 5 is 0.6 mm (1D).

[0047] As a specific solution of this embodiment, the jet angle α of the circular air film hole 5 (that is, the angle between the circular air film hole 5 and the horizontal plane) is 45°.

[0048] As a specific solution of this embodiment, the spacing between two adjacent circular air film holes 5 in the longitudinal direction is 4 mm, and the spacing between two adjacent circular air film holes 5 in the transverse direction is 4 mm; the vertical distance from the top of the circular air film hole 5 to the bottom surface of the ceramic-based composite plate (equal to the thickness h of the ceramic-based composite plate) is 3.25 mm.

[0049] In one embodiment of the present invention, substrate 3 is made of high-temperature ceramics, such as silicon carbide, silicon nitride, or boron nitride ceramics; yarn 2 is made of high-strength fibers, such as carbon fibers or silicon carbide fibers; and coating 1 is made of high-temperature-resistant rare earth silicates, such as Yb2SiO5 and Yb2Si2O7+Si.

[0050] Comparative Example 1 Yarn combination hole:

[0051] This comparative example provides a layout structure of air film holes for ceramic-based composite components taking into account coating shedding. The layout structure of air film holes is arranged on a ceramic-based composite plate; Figure 3 As shown, the structure is basically the same as that of Example 1, with the difference that the forward-inclined expansion hole 4 and the circular air film hole 5 are both opened on the yarn 2.

[0052] Comparative Example 2: Circular hole of substrate:

[0053] This comparative example provides a layout structure of air film holes for ceramic-based composite components taking into account coating shedding. The layout structure of air film holes is arranged on a ceramic-based composite plate; Figure 4 As shown, the ceramic-based composite plate includes a substrate 3 and yarns 2, and the outer surface of the substrate 3 is coated with a coating 1;

[0054] The ceramic-based composite plate includes a high temperature gradient region and a low temperature gradient region. Both the high temperature gradient region and the low temperature gradient region are provided with a plurality of circular air film holes 5 to form a matrix structure. The circular air film holes 5 are opened on the substrate 3.

[0055] In this embodiment, the structure and arrangement spacing of the circular air film holes 5 are exactly the same as those in embodiment 1.

[0056] Comparative Example 3 Yarn Hole:

[0057] This comparative example provides a layout structure of air film holes for ceramic-based composite components taking into account coating shedding. The layout structure of air film holes is arranged on a ceramic-based composite plate; Figure 4 As shown, the structure is basically the same as that of comparative example 2, with the difference being that the circular air film hole 5 is opened on the yarn 2.

[0058] Effect verification:

[0059] In order to verify the effect of the present invention on the temperature gradient and the comprehensive cooling efficiency, a computer simulation comparison was conducted on the four air film hole layout structures of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3. The simulation parameters are as follows: the mainstream air flow velocity is 15m / s, the mainstream inlet temperature is 450K, the secondary flow temperature is 300K, and the flow rate meets the blowing ratio of 0.8. The simulation results are shown in Figure 2. Figure 6 、 Figure 7 、 Figure 8 and Figure 9 shown.

[0060] Depend on Figure 6 and Figure 7 It can be seen that when the film hole layout is cylindrical, the temperature gradient on the flat plate surface is large and primarily concentrated in areas not covered by the cylindrical film hole layout. Compared to the flat plate surface temperature gradient with the cylindrical film hole layout, the combined layout of forward-inclined fan-shaped holes and cylindrical film holes significantly reduces the temperature gradient. The surface average temperature gradients of the yarn combination holes and the matrix combination holes are reduced by 9.3% and 8.9%, respectively, compared to the yarn circular holes. Clearly, this film hole layout scheme can effectively reduce the temperature gradient on the flat plate.

[0061] Depend on Figure 8 and Figure 9 It can be seen that when the air film hole layout is the base combination hole embodiment 1, the overall cooling efficiency is improved to a certain extent compared with the yarn circular hole comparison example 3 and the base circular hole comparison example 2, and the overall cooling efficiency is improved by about 2% compared with the yarn circular hole. However, the yarn combination hole comparison example 1 has a lower overall cooling efficiency than the air film hole layout scheme of the comparative example, a decrease of about 1.6%. Clearly, this air film hole layout scheme does not meet the expected effect requirements.

[0062] In summary, when the air film hole layout is the base combination hole of Example 1, it can meet the requirements of achieving the effect of reducing the temperature gradient and maintaining or increasing the comprehensive cooling effect.

Claims

1. A ceramic matrix composite component air film hole layout structure considering coating shedding, the ceramic matrix composite component comprising a matrix (3) and a yarn (2), wherein the outer surface of the matrix (3) is coated with a coating (1); Its characteristics are: The ceramic matrix composite material component comprises a high temperature gradient region and a low temperature gradient region, wherein a plurality of forward-inclined expansion holes (4) are arranged on the high temperature gradient region, and a plurality of circular air film holes (5) are arranged on the low temperature gradient region; the forward-inclined expansion holes (4) and the circular air film holes (5) are both opened on the substrate (3).

2. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 1, characterized in that: The forward-inclined expansion hole (4) comprises a first hole section (401) with a cylindrical structure and a second hole section (402) with an irregular platform structure.

3. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 2, characterized in that: The diameter of the first hole section (401) is D; The second hole segment (402) has the largest top area and the smallest bottom area; its top is an irregular hole with a maximum width of 1.8D to 2.0D in the transverse direction and a maximum length L in the longitudinal direction. P The bottom end thereof is a circular hole, and the bottom end hole diameter is equal to the diameter D of the first hole section (401).

4. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 2, characterized in that: The top end of the second hole section (402) is composed of two oppositely arranged curved edges (40201) of exactly the same shape and two long parallel straight edges (40202) of different lengths.

5. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 4, characterized in that: The curved edge (40201) is composed of multiple arc edges. The radii of the arc edges from front to back are 0.425D, 0.551D, 0.656D, 0.766D, 0.901D, 1.006D, 1.069D, 1.042D, 1.564D, 1.454D, 1.321D, 1.033D, 0.722D, 0.486D, and 0.313D respectively; The lengths of the two straight edges (40202) are 0.35D to 0.45D and 0.9D to 1.5D respectively.

6. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 1, characterized in that: The jet angle α of the forward-inclined expansion hole (4) is 45°, the forward-inclined angle β is 11°, and the spanwise expansion angle γ is 11°.

7. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 2, characterized in that: The distance L between two adjacent forward-inclined expansion holes (4) in the longitudinal direction M The distance L between two adjacent forward-inclined expansion holes (4) in the transverse direction is 6D to 7D. S The vertical distance from the top of the forward-inclined expansion hole (4) to the bottom surface of the ceramic-based composite material component is 5D to 6D.

8. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 1, characterized in that: The circular air film hole (5) is a cylindrical structure, and its diameter is equal to D.

9. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 1, characterized in that: The jet angle α of the circular air film hole (5) is 45°.

10. The air film hole layout structure of a ceramic matrix composite component considering coating shedding as claimed in claim 1, characterized in that: The distance between two adjacent circular air film holes (5) in the longitudinal direction is 6D to 7D, and the distance between two adjacent circular air film holes (5) in the transverse direction is 6D to 7D; the vertical distance from the top of the circular air film hole (5) to the bottom surface of the ceramic-based composite material component is 5D to 6D.

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