A composite wall cooling structure for a turbine blade and a method of manufacturing the same

Abstract

This invention provides a composite wall cooling structure for turbine blades and its manufacturing method, belonging to the field of gas turbine hot-end component design and manufacturing technology. The composite wall cooling structure includes: a blade substrate with an internal cooling channel and a near-surface external cooling channel on its surface, the latter communicating with the internal cooling channel; a functional layer made of a thermally conductive, oxidation-resistant, and heat-corrosion-resistant material, disposed on the surface of the blade substrate; and a thermal barrier coating disposed on the surface of the functional layer. Film cooling pores are provided on the functional layer and the thermal barrier coating, penetrating both and communicating with the near-surface external cooling channel. This composite wall cooling structure can significantly improve the cooling efficiency and service life of turbine blades, and its manufacturing method is simple and easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine hot-end component design and manufacturing technology, specifically relating to a composite wall cooling structure for turbine blades and its manufacturing method. Background Technology

[0002] Gas turbines are core components of modern energy and aerospace propulsion systems, and their efficiency is closely related to the turbine inlet temperature. Turbine blades operate in extreme environments of high temperature, high pressure, and high-speed rotation for extended periods, and their temperature resistance directly determines the overall efficiency and reliability of the turbine. To overcome the limitations of the melting point of nickel-based superalloy materials, modern advanced turbine blades generally employ complex internal cooling channels and film cooling hole structures, and thermal barrier coatings (TBCs) are prepared on the surface of nickel-based superalloys to achieve thermal protection.

[0003] Currently, one of the most advanced cooling technologies is the double-wall cooling structure, which involves constructing dense microchannels and impingement cooling structures within the blade wall to achieve near-wall cooling. However, the fabrication of such structures faces the following significant challenges.

[0004] Casting challenges: Traditional investment casting processes struggle to form double-walled cooling structures with complex, fine, and closed internal channels, resulting in low yields and limited design freedom.

[0005] Welding challenges: The solution of welding two plates with grooves on each has problems such as the weld becoming a weak point at high temperatures, welding deformation, and the weld potentially blocking microchannels, making it difficult to guarantee reliability.

[0006] Material limitations: The base material of the blades is usually a nickel-based high-temperature alloy, which has limited thermal conductivity. Even with internal cooling, heat still needs to be conducted to the cooling medium through the base material, resulting in high thermal resistance.

[0007] While 3D printing (additive manufacturing) technology offers new possibilities for shaping complex turbine blade structures, simply using 3D printing to manufacture the entire turbine blade faces challenges such as difficulty in meeting material performance requirements (such as fatigue performance), high costs, and poor surface finish.

[0008] Therefore, there is an urgent need in this field for a new turbine blade cooling solution that can overcome existing manufacturing bottlenecks and has high performance, high reliability and good processing feasibility. Summary of the Invention

[0009] The purpose of this invention is to overcome the difficulties in casting and welding of existing double-wall cooling structures for turbine blades, as well as the insufficient thermal conductivity of the base material, and to provide a composite wall cooling structure for turbine blades and its manufacturing method. This composite wall cooling structure features a novel design, simple and feasible processing, and good cooling effect. The manufacturing method employs a "reduction-then-addition" composite manufacturing strategy, aiming to:

[0010] 1. Achieve reliable manufacturing of complex and efficient near-wall cooling channels.

[0011] 2. Introduce a high thermal conductivity and high temperature resistance intermediate functional layer between the turbine blade substrate and the thermal barrier coating to reduce thermal resistance.

[0012] 3. Ultimately, this achieves a significant reduction in the operating temperature of the turbine blade substrate, thereby greatly improving the creep life and thermal fatigue life of the turbine blade.

[0013] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a composite wall cooling structure for turbine blades and a method for manufacturing the same.

[0014] In a first aspect, embodiments of the present invention provide a composite wall cooling structure for turbine blades, the composite wall cooling structure comprising: The blade substrate has an internal cooling channel and a near-surface external cooling channel on its surface, which is connected to the internal cooling channel. The functional layer is made of a thermally conductive, oxidation-resistant, and hot-corrosion-resistant material. The thermally conductive, oxidation-resistant, and hot-corrosion-resistant material is at least one of a nickel-based high-temperature alloy, a cobalt-based high-temperature alloy, and a metal matrix reinforced by ceramic particle dispersion. The metal matrix is ​​at least one of a nickel-based high-temperature alloy, a cobalt-based high-temperature alloy, and an iron-based high-temperature alloy. The functional layer is disposed on the surface of the blade substrate. A thermal barrier coating, wherein the thermal barrier coating is disposed on the surface of the functional layer; The functional layer and the thermal barrier coating are provided with air film pores on the blade surface that penetrate the functional layer and the thermal barrier coating, and the air film pores on the blade surface are connected to the near-surface external cooling channel.

[0015] In some embodiments, the cross-sectional shape of the near-surface external cooling channel is T-shaped in the direction from the thermal barrier coating to the blade substrate.

[0016] In some embodiments, the air film pores on the blade surface are inclined relative to the blade substrate in the direction from the thermal barrier coating to the blade substrate.

[0017] In some embodiments, the ceramic particles are at least one of fully stabilized zirconium oxide, yttrium-stabilized zirconium oxide, and GaYbYZrO2.

[0018] In some embodiments, the volume fraction of the ceramic particles is 5% to 30%, with the total volume of the metal matrix reinforced by the ceramic particles being 100%.

[0019] In some embodiments, in the functional layer, the volume fraction of the ceramic particles increases gradually from the side closer to the blade substrate to the side farther from the blade substrate.

[0020] In some embodiments, the thickness of the functional layer is 30~1000μm.

[0021] In some embodiments, the thermal barrier coating includes an adhesive layer and a ceramic layer, the adhesive layer being disposed on the side of the functional layer away from the blade substrate, and the ceramic layer being disposed on the side of the adhesive layer away from the functional layer.

[0022] Secondly, embodiments of the present invention provide a method for manufacturing a composite wall cooling structure for a turbine blade, the method comprising the following steps: S1. A blade substrate is provided, wherein an internal cooling channel for the blade is provided inside the blade substrate; S2. Using precision machining technology, a near-surface external cooling channel is machined on the surface of the blade substrate at a position corresponding to the internal cooling channel of the blade, which communicates with the internal cooling channel of the blade; S3. The thermally conductive, antioxidant, and heat-corrosion resistant material is deposited layer by layer on the surface of the blade substrate using 3D printing technology to obtain a functional layer; S4. A thermal barrier coating is formed on the surface of the functional layer; S5. Using a drilling technique, air film pores are machined on the functional layer and the thermal barrier coating at positions corresponding to the near-surface external cooling channel, so that the air film pores on the blade surface are connected to the near-surface external cooling channel, thereby obtaining the composite wall cooling structure.

[0023] In some embodiments, the precision machining technology is micro-milling technology, laser engraving technology, or electrical discharge machining technology.

[0024] In some embodiments, the 3D printing technology is laser directional energy deposition technology or laser selective melting technology.

[0025] Compared with traditional double-wall cooling structures and their casting or welding techniques, the composite wall cooling structure and its manufacturing method according to the embodiments of the present invention have the following significant advantages: 1. The manufacturing process of this invention is a breakthrough, and the processing is simple and feasible: (1) The manufacturing method of this invention breaks down the complex internal three-dimensional cooling channel manufacturing into two relatively simple and mature steps: "surface precision machining" and "3D printing cover packaging". This results in near-surface external cooling channels, perfectly avoiding the molding difficulties and welding reliability issues of traditional double-wall cooling structure casting.

[0026] (2) The manufacturing method of the present invention adopts the composite manufacturing concept of "reduction first and then addition", which gives full play to the advantages of the two manufacturing technologies. The process flow is clear, the controllability is strong, and the yield is high.

[0027] 2. Significantly improved cooling efficiency: (1) In the composite wall cooling structure of the present invention, the near-surface external cooling channel is "embedded" inside the high thermal conductivity functional layer, realizing true "near-wall cooling", and the heat is efficiently carried away before reaching the blade substrate.

[0028] (2) In the composite wall cooling structure of the present invention, the high thermal conductivity of the functional layer itself further enhances the transverse heat conduction, making the temperature distribution of the entire blade wall more uniform and reducing the working temperature of the blade substrate by 100℃ ~ 300℃.

[0029] 3. Significantly improved overall performance and service life: (1) The composite wall cooling structure of the present invention can significantly reduce the working temperature of the blade substrate, which directly leads to a multiple extension of the creep life and anti-oxidation / corrosion life of the turbine blade.

[0030] (2) The composite wall cooling structure of the present invention provides a high degree of freedom for the design of turbine blade cooling, and can realize complex and efficient cooling flow patterns that were previously impossible to achieve. Attached Figure Description

[0031] Figure 1 This is a cross-sectional schematic diagram of the composite wall cooling structure according to an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures: 1-blade substrate; 2-inner cooling channel of the blade; 3-outer cooling channel near the surface; 4-functional layer; 5-thermal barrier coating; 51-adhesive layer; 52-ceramic layer; 6-film cooling pores on the blade surface. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] In a first aspect, embodiments of the present invention provide a composite wall cooling structure for turbine blades, such as... Figure 1 As shown, the composite wall cooling structure includes: The blade base 1 has an internal cooling channel 2 inside and a near-surface external cooling channel 3 on the surface of the blade base 1, which is connected to the internal cooling channel 2. Functional layer 4 is made of a thermally conductive, oxidation-resistant, and hot-corrosion-resistant material. The thermally conductive, oxidation-resistant, and hot-corrosion-resistant material is at least one of nickel-based high-temperature alloy, cobalt-based high-temperature alloy, and ceramic particle dispersion-reinforced metal matrix. The metal matrix is ​​at least one of nickel-based high-temperature alloy, cobalt-based high-temperature alloy, and iron-based high-temperature alloy. Functional layer 4 is disposed on the surface of blade substrate 1. Thermal barrier coating 5 is disposed on the surface of functional layer 4; The functional layer 4 and the thermal barrier coating 5 are provided with air film pores 6 on the blade surface that penetrate the functional layer 4 and the thermal barrier coating 5. The air film pores 6 on the blade surface are connected to the near-surface external cooling channel 3.

[0035] This invention employs a composite wall cooling structure consisting of a blade substrate, a functional layer, and a thermal barrier coating. The blade substrate surface has precision-machined near-surface external cooling channels that connect with internal cooling channels within the blade substrate. The functional layer on the blade substrate surface is made of a thermally conductive, oxidation-resistant, and heat-corrosion-resistant material. Both the functional layer and the thermal barrier coating contain surface air film pores that connect to the near-surface external cooling channels. This design transforms the traditional double-wall cooling structure's "substrate heat-bearing + internal cooling" model into a new model of "functional layer active heat conduction and cooling + substrate protection." This composite wall cooling structure is novel in design, simple and feasible to manufacture, and provides excellent cooling performance.

[0036] In some embodiments, the cross-sectional shape of the near-surface external cooling channel 3 is T-shaped in the direction from the thermal barrier coating 5 to the blade substrate 1. This can increase the heat exchange area and improve cooling efficiency.

[0037] In some embodiments, the air film vents 6 on the blade surface are inclined relative to the blade substrate 1 in the direction from the thermal barrier coating 5 to the blade substrate 1. This ensures that the airflow from the air film vents on the blade surface adheres to the turbine blade surface, providing good thermal insulation.

[0038] In the composite wall cooling structure of this invention, the functional layer is made of a thermally conductive, oxidation-resistant, and hot-corrosion-resistant material. This material is at least one of a nickel-based superalloy, a cobalt-based superalloy, and a ceramic particle dispersion-reinforced metal matrix. The metal matrix is ​​at least one of a nickel-based superalloy, a cobalt-based superalloy, and an iron-based superalloy. The materials described above possess high thermal conductivity, oxidation resistance, and hot-corrosion resistance, making them suitable for the working environment of turbine blades and contributing to improved cooling efficiency of the composite wall cooling structure.

[0039] In some embodiments, the ceramic particles are at least one of fully stabilized zirconium oxide, yttrium-stabilized zirconium oxide (YSZ), and GaYbYZrO2. The ceramic particles listed above are oxide materials with high thermal conductivity, high hardness, and good compatibility with the metal matrix, which is beneficial for improving the thermal conductivity of the functional layer.

[0040] In some embodiments, with the total volume of the ceramic particle-reinforced metal matrix being 100%, the volume fraction of the ceramic particles is 5% to 30%, for example, 5%, 10%, 15%, 20%, 25%, 30%, etc. Meeting these conditions is beneficial for improving the oxidation resistance and hot corrosion resistance of the functional layer.

[0041] In some embodiments, in the functional layer 4, the volume fraction of ceramic particles gradually increases from the side closest to the blade substrate 1 to the side furthest from the blade substrate 1. Meeting these conditions is beneficial for improving the oxidation resistance and hot corrosion resistance of the functional layer.

[0042] In some embodiments, the thickness of the functional layer 4 is 30~1000μm, such as 30μm, 50μm, 100μm, 200μm, 400μm, 600μm, 800μm, 1000μm, etc. When the thickness of the functional layer is too thin, it is not conducive to improving the turbine blade's resistance to oxidation and hot corrosion. When the thickness of the functional layer is too thick, it will generate greater internal stress, which is not conducive to improving the turbine blade's cycle life.

[0043] In some embodiments, the thermal barrier coating 5 includes an adhesive layer 51 disposed on the surface of the functional layer 4 and a ceramic layer 52 disposed on the surface of the adhesive layer 51. The adhesive layer 51 is made of materials such as MCrAlY or PtAl, and the ceramic layer 52 is made of materials such as yttrium-stabilized zirconium oxide (YSZ). The adhesive layer acts as a buffer structure between the ceramic layer and the blade substrate, reducing the mismatch in thermal expansion coefficients and thus improving the thermal barrier coating's thermal cycling life. Simultaneously, as an antioxidant and anti-corrosion material, it reduces oxidation and thermal corrosion consumption of the blade substrate. Furthermore, the high-temperature strength and wear resistance of these adhesive layer materials are superior to ordinary alloys, providing a more robust adhesive layer for the thermal barrier coating and reducing the risk of peeling off.

[0044] Secondly, embodiments of the present invention provide a method for manufacturing a composite wall cooling structure for a turbine blade, the method comprising the following steps: S1. Provide a blade base 1, and the blade base 1 is provided with an internal cooling channel 2; S2. Using precision machining technology, a near-surface external cooling channel 3 is machined on the surface of the blade substrate 1 at a position corresponding to the blade internal cooling channel 2, and is connected to the blade internal cooling channel 2; S3. Using 3D printing technology, thermally conductive, oxidation-resistant, and heat-corrosion-resistant materials are deposited layer by layer on the surface of the blade substrate 1 to obtain the functional layer 4; S4. A thermal barrier coating 5 is formed on the surface of functional layer 4; S5. Using a drilling technique, air film holes 6 are machined on the functional layer 4 and the thermal barrier coating 5 at positions corresponding to the near-surface external cooling channel 3, so that the air film holes 6 on the blade surface are connected to the near-surface external cooling channel 3, thus obtaining a composite wall cooling structure.

[0045] Step S1 provides a blade substrate with an internal cooling channel. How to fabricate the internal cooling channel within the blade substrate can be found in relevant technologies; this is not the focus of this embodiment and will not be elaborated upon here. Step S2 uses precision machining technology to fabricate a near-surface external cooling channel. The advantage of this step is that it avoids the difficulty of creating a closed, complex internal cavity required by traditional double-wall cooling structures, simplifying the three-dimensional sealing problem to two-dimensional or 2.5-dimensional surface machining. The process is mature and highly controllable. Step S3 uses 3D printing technology to deposit a functional layer that covers the entire surface of the blade substrate, sealing the near-surface external cooling channel. Step S4 fabricates a thermal barrier coating on the surface of the functional layer. Step S5 then uses drilling technology to fabricate film pores on the blade surface, ultimately obtaining the composite wall cooling structure.

[0046] Understandable Figure 1 The illustration only shows a partial view of the turbine blade. In reality, each area of ​​the turbine blade is equipped with a composite wall cooling structure. The depth, width, and distribution of the near-surface external cooling channels, as well as the width and distribution of the air film pores on the blade surface, need to be individually designed according to the heat load of each area of ​​the turbine blade to meet the cooling effect. This is not the focus of this embodiment of the invention and will not be elaborated here.

[0047] During the deposition process in step S3, by precisely controlling the process parameters, the functional layer can completely cover and encapsulate the near-surface external cooling channel processed in step S2, thereby forming a closed cooling channel embedded inside the functional layer. At the same time, due to its high thermal conductivity, the functional layer itself can quickly conduct heat from the blade surface laterally to the cooling medium (cooling medium refers to air, water vapor, or other cooling media used for cooling inside the blade) in the near-surface external cooling channel.

[0048] In some embodiments, the precision machining technology is micro-milling technology, laser engraving technology, or electrical discharge machining technology, etc.

[0049] In some embodiments, the 3D printing technology is laser-directed energy deposition (L-DED) or selective laser melting (SLM), etc.

[0050] Step S4 may specifically include the following steps: S4-1. Surface treatment: The surface of the functional layer is finished (e.g., polished) to improve the surface finish; S4-2. Preparation of thermal barrier coating: A bonding layer (e.g., MCrAlY or PtAl) is prepared on the surface of the functional layer using supersonic flame spraying (HVOF), electroplating, or physical vapor deposition (EB-PVD). Then, a ceramic layer (e.g., yttrium-stabilized zirconium oxide, YSZ) is prepared on the surface of the bonding layer using atmospheric plasma spraying (APS) or electron beam physical vapor deposition (EB-PVD). The bonding layer and the ceramic layer together form the final thermal protection surface, i.e., the thermal barrier coating.

[0051] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0052] Example 1 1. Provide a blade substrate; wherein the material of the blade substrate is a nickel-based high-temperature alloy K480, and the blade substrate has an internal cooling channel.

[0053] 2. Using micro-milling technology, a near-surface external cooling channel is machined on the surface of the blade substrate at a position corresponding to the internal cooling channel of the blade; wherein, the cross-sectional shape of the near-surface external cooling channel is T-shaped from the thermal barrier coating to the blade substrate.

[0054] 3. A thermally conductive, oxidation-resistant, and heat-corrosion-resistant material is deposited layer by layer on the surface of the blade substrate using laser-directed energy deposition (L-DED) technology to obtain a functional layer with a thickness of 300 nm; wherein, the thermally conductive, oxidation-resistant, and heat-corrosion-resistant material is a nickel-based high-temperature alloy Haynes214.

[0055] 4. The surface of the functional layer is polished, and then a 200 μm thick MCrAlY layer is prepared on the surface of the polished functional layer using high-velocity flame spraying (HVOF) technology as an adhesive layer. Then, an 400 μm thick YSZ layer is prepared on the surface of the MCrAlY layer using atmospheric plasma spraying (APS) technology as a ceramic layer. The MCrAlY layer and the YSZ layer together form a thermal barrier coating (TBCs).

[0056] 5. Using drilling technology, air film pores are machined on the functional layer and thermal barrier coating at positions corresponding to the near-surface external cooling channels, connecting the functional layer and thermal barrier coating. This allows the air film pores on the blade surface to connect with the near-surface external cooling channels, ultimately resulting in a composite wall cooling structure for the turbine blade.

[0057] Example 2 1. Provide a blade substrate; wherein the material of the blade substrate is a nickel-based high-temperature alloy K4222, and the blade substrate has an internal cooling channel.

[0058] 2. Using laser engraving technology, a near-surface external cooling channel is machined on the surface of the blade substrate at a position corresponding to the internal cooling channel of the blade; wherein, the cross-sectional shape of the near-surface external cooling channel is T-shaped from the thermal barrier coating to the blade substrate.

[0059] 3. A thermally conductive, oxidation-resistant, and heat-corrosion-resistant material is deposited layer by layer on the surface of the blade substrate using selective laser melting (SLM) technology to obtain a functional layer with a thickness of 500 nm; wherein, the thermally conductive, oxidation-resistant, and heat-corrosion-resistant material is a fully stable zirconium oxide.

[0060] 4. The surface of the functional layer is polished, and then a 300 μm thick MCrAlY layer is prepared on the surface of the polished functional layer using high-velocity flame spraying (HVOF) technology as an adhesive layer. Then, an 800 μm thick YSZ layer is prepared on the surface of the MCrAlY layer using atmospheric plasma spraying (APS) technology as a ceramic layer. The MCrAlY layer and the YSZ layer together form a thermal barrier coating (TBCs).

[0061] 5. Using drilling technology, air film pores are machined on the functional layer and thermal barrier coating at positions corresponding to the near-surface external cooling channels, connecting the functional layer and thermal barrier coating. This allows the air film pores on the blade surface to connect with the near-surface external cooling channels, ultimately resulting in a composite wall cooling structure for the turbine blade.

[0062] Example 3 1. Provide a blade substrate; wherein the material of the blade substrate is a nickel-based high-temperature alloy K411, and the blade substrate has an internal cooling channel.

[0063] 2. Using micro-milling technology, a near-surface external cooling channel is machined on the surface of the blade substrate at a position corresponding to the internal cooling channel of the blade; wherein, the cross-sectional shape of the near-surface external cooling channel is T-shaped from the thermal barrier coating to the blade substrate.

[0064] 3. A thermally conductive, oxidation-resistant, and heat-corrosion-resistant material was deposited layer by layer on the surface of the blade substrate using laser-directed energy deposition (L-DED) technology to obtain a functional layer with a thickness of 200 nm. The thermally conductive, oxidation-resistant, and heat-corrosion-resistant material is a composite material of a metal matrix reinforced by dispersed ceramic particles. The ceramic particles are 14YSZ, and the metal matrix is ​​a nickel-based high-temperature alloy Haynes214. In the functional layer, the volume fraction of ceramic particles gradually increases from the side closer to the blade substrate to the side farther away from the blade substrate, within the range of 5% to 30%.

[0065] 4. The surface of the functional layer is polished, and then a 300 μm thick MCrAlY layer is prepared on the surface of the polished functional layer using high-velocity flame spraying (HVOF) technology as an adhesive layer. Then, a 500 μm thick YSZ layer is prepared on the surface of the MCrAlY layer using atmospheric plasma spraying (APS) technology as a ceramic layer. The MCrAlY layer and the YSZ layer together form a thermal barrier coating (TBCs).

[0066] 5. Using drilling technology, air film pores are machined on the functional layer and thermal barrier coating at positions corresponding to the near-surface external cooling channels, connecting the functional layer and thermal barrier coating. This allows the air film pores on the blade surface to connect with the near-surface external cooling channels, ultimately resulting in a composite wall cooling structure for the turbine blade.

[0067] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0068] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A composite wall cooling structure for turbine blades, characterized in that, The composite wall cooling structure includes: The blade substrate has an internal cooling channel and a near-surface external cooling channel on its surface, which is connected to the internal cooling channel. The functional layer is made of a thermally conductive, oxidation-resistant, and hot-corrosion-resistant material. This material is a ceramic particle-reinforced metal matrix, and the metal matrix is ​​at least one of a nickel-based high-temperature alloy, a cobalt-based high-temperature alloy, and an iron-based high-temperature alloy. The functional layer is disposed on the surface of the blade substrate. With the total volume of the ceramic particle-reinforced metal matrix being 100%, the volume fraction of the ceramic particles is 5% to 30%. In the functional layer, the volume fraction of the ceramic particles gradually increases from the side closest to the blade substrate to the side furthest from the blade substrate. A thermal barrier coating is disposed on the surface of the functional layer; the thermal barrier coating includes an adhesive layer and a ceramic layer, the adhesive layer being disposed on the side of the functional layer away from the blade substrate, and the ceramic layer being disposed on the side of the adhesive layer away from the functional layer; The functional layer and the thermal barrier coating are provided with air film pores on the blade surface that penetrate the functional layer and the thermal barrier coating, and the air film pores on the blade surface are connected to the near-surface external cooling channel.

2. The composite wall cooling structure according to claim 1, characterized in that, The cross-sectional shape of the near-surface external cooling channel is T-shaped in the direction from the thermal barrier coating to the blade substrate.

3. The composite wall cooling structure according to claim 1, characterized in that, The air film pores on the blade surface are inclined relative to the blade substrate in the direction from the thermal barrier coating to the blade substrate.

4. The composite wall cooling structure according to claim 1, characterized in that, The ceramic particles are at least one of fully stabilized zirconium oxide, yttrium-stabilized zirconium oxide, and GaYbYZrO2.

5. The composite wall cooling structure according to claim 1, characterized in that, The thickness of the functional layer is 30~1000μm.

6. A method for manufacturing a composite wall cooling structure for a turbine blade according to any one of claims 1 to 5, characterized in that, The manufacturing method includes the following steps: S1. A blade substrate is provided, wherein an internal cooling channel for the blade is provided inside the blade substrate; S2. Using precision machining technology, a near-surface external cooling channel is machined on the surface of the blade substrate at a position corresponding to the internal cooling channel of the blade, which communicates with the internal cooling channel of the blade; S3. The thermally conductive, antioxidant, and heat-corrosion resistant material is deposited layer by layer on the surface of the blade substrate using 3D printing technology to obtain a functional layer; S4. A thermal barrier coating is formed on the surface of the functional layer; S5. Using a drilling technique, air film pores are machined on the functional layer and the thermal barrier coating at positions corresponding to the near-surface external cooling channel, so that the air film pores on the blade surface are connected to the near-surface external cooling channel, thereby obtaining the composite wall cooling structure.

7. The manufacturing method according to claim 6, characterized in that, The precision machining technology is micro-milling, laser engraving, or electrical discharge machining; and / or, the 3D printing technology is laser directional energy deposition or laser selective melting.

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