Turbine blade cooling passage design method based on three-period minimal surface structure and turbine blade

Abstract

This invention discloses a design method for a turbine blade cooling channel based on a three-period minimal surface structure and a turbine blade. The method first analyzes the distribution characteristics of the cooling medium in the cooling cavity under centrifugal force based on the turbine blade's rotational operating conditions. The direction from the suction side to the pressure side is designated as the gradient design direction. Based on the distribution characteristics, the variation law of key parameters controlling the geometric features of the three-period minimal surface structure along this direction is determined. Then, within a regular parameter space, the generation of the three-period minimal surface is controlled according to this law, causing its local geometric features to change with position, generating a parameterized model with predetermined gradient characteristics. Finally, through geometric transformation, the model is transformed and fitted to the three-dimensional physical space of the turbine blade cooling cavity, generating a three-dimensional design model that fits the inner wall and maintains the gradient characteristics. The purpose of this invention is to solve the geometric and physical field adaptation problems of TPMS structures in the internal cooling application of aerospace engine turbine blades, thereby achieving efficient and uniform cooling of aerospace engine turbine blades under real operating conditions.

Description

Technical Field

[0001] This invention belongs to the field of aerospace engine turbine blade cooling technology, specifically relating to a turbine blade cooling channel design method based on a three-period minimal curved surface structure and a turbine blade. Background Technology

[0002] As a core hot-end component of aerospace engines, turbine blades operate in extreme high-temperature combustion environments for extended periods. The effectiveness of their internal cooling technology directly determines the engine's thrust and lifespan. Currently, serpentine channel cooling technology is commonly used in the mid-chord region of turbine blades, where cooling gas continuously removes heat through the flow of cooling gas within complex, curved channels. However, this cooling technology has inherent drawbacks: the cooling gas is prone to flow separation and secondary flow in the bends and straight sections of the serpentine channel, leading to severely uneven flow rate and heat transfer distribution. This makes localized high-temperature points easily form on the turbine blade surface, affecting turbine blade life and engine reliability. Furthermore, the curved structure of the serpentine channel results in high flow resistance, requiring more high-pressure cooling gas to achieve the desired cooling effect, thus reducing the overall efficiency of the engine.

[0003] In pursuit of higher heat transfer efficiency and compactness, Triply Periodic Minimal Surface (TPMS) structures have attracted widespread attention in the field of high-efficiency heat transfer. TPMS structures are continuously and periodically distributed in three-dimensional space, exhibiting extremely high specific surface area and excellent fluid connectivity. Its core advantages in heat transfer applications are: (1) extremely high surface area to volume ratio, which can maximize the heat transfer area in a limited space and significantly enhance convective heat transfer; (2) continuous and smooth flow channel topology, which can promote uniform fluid distribution and reduce flow dead zones, achieving smoother flow while reducing flow resistance; (3) lightweight and high-strength characteristics, whose continuous cell structure can significantly reduce weight while ensuring load-bearing performance, which is very much in line with the stringent requirements for weight reduction of components in the aerospace field. These advantages have made TPMS-based heat transfer structures a research hotspot in the current heat transfer field.

[0004] Despite the significant advantages of TPMS structures, their application in the internal cooling of high-speed rotating turbine blades in aerospace engines still faces two levels of technical challenges: The first level is the geometric adaptation challenge. Aerospace engine turbine blades, to meet aerodynamic and structural requirements, have highly irregular shapes and complex three-dimensional twists, while TPMS structures are essentially mathematically strictly periodic structures. Therefore, there is a problem of fitting regular TPMS structures to conformally fit the irregular inner walls of the turbine blade cavity. The more critical second level is the physical field adaptation challenge. For high-speed rotating turbine blades, the strong centrifugal force field fundamentally alters the flow behavior of the cooling medium, resulting in severe flow and pressure gradients across the cavity cross-section. Specifically, the cooling medium accumulates on the pressure side of the turbine blade under centrifugal force, leading to excessive flow on the pressure side and insufficient flow on the suction side. Even if a geometrically conformal TPMS structure is achieved, this inherent flow inhomogeneity will be inherited or even amplified within the TPMS channel, making truly uniform and efficient cooling impossible. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a turbine blade cooling channel design method and turbine blade based on a three-period minimal curved surface structure. The purpose is to overcome the defects of existing cooling technologies and solve the geometric and physical field adaptation problems of TPMS structure in the internal cooling application of aerospace engine turbine blades, thereby achieving efficient and uniform cooling of aerospace engine turbine blades under real working conditions.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: According to a first aspect of the present invention, a method for designing a cooling channel for a turbine blade based on a three-period minimal surface structure is provided, for constructing a cooling channel in a cooling cavity inside the turbine blade, comprising: Based on the rotational conditions of the turbine blades, the distribution characteristics of the cooling medium caused by centrifugal force in the cooling cavity are analyzed. The direction from the suction side to the pressure side of the turbine blade is defined as the gradient design direction. Based on the distribution characteristics, the variation law of the key parameters controlling the geometric features of the three-period minimal surface structure along the gradient design direction is determined. Within the regular parameter space, the generation process of the three-period minimal surface is controlled according to the change law, so that the local geometric features of the three-period minimal surface change accordingly with the change of the location of the local geometric features along the gradient design direction, thereby generating a parameterized model of the three-period minimal surface with predetermined gradient features in the parameter space. By using geometric transformation methods, the three-period minimal surface parameterized model is transformed as a whole and fitted into the three-dimensional physical space of the turbine blade cooling cavity, generating a three-dimensional design model that fits the inner wall of the cooling cavity and maintains the gradient characteristics.

[0007] In one possible implementation of the first aspect, the key parameter is a threshold parameter that controls the size of the three-period minimal surface fluid domain. The variation law is constructed such that the threshold parameter has a minimum value on the turbine blade suction side and a maximum value on the turbine blade pressure side, and changes continuously and monotonically between the turbine blade suction side and the turbine blade pressure side, so that the equivalent aperture of the fluid domain of the three-period minimal surface structure decreases continuously from the turbine blade suction side to the turbine blade pressure side.

[0008] In one possible implementation of the first aspect, the law of change is expressed in functional form:

[0009] in, Normalized coordinates are used along the direction from the suction side of the turbine blade to the pressure side of the turbine blade. for Threshold parameter value at the location, and They are respectively s =0 and s The threshold parameter value at =1; Let be a function that is continuously and monotonically increasing in the interval [0,1].

[0010] In one possible implementation of the first aspect, the geometric transformation method is an isoparametric mapping method, which realizes the transformation between parametric space coordinates and physical space coordinates through shape functions.

[0011] In one possible implementation of the first aspect, after generating the three-dimensional design model that fits the inner wall of the cooling cavity and maintains the gradient features, the method further includes: The three-dimensional design model is converted into a data format recognizable by additive manufacturing equipment for the manufacture of turbine blades.

[0012] According to a second aspect of the present invention, a turbine blade based on a three-period minimal surface structure is provided, comprising a turbine blade body, wherein a cooling cavity is disposed inside the turbine blade body, the cooling cavity is filled with a three-period minimal surface structure, the interconnecting pores of the three-period minimal surface structure constitute cooling fluid channels, the equivalent aperture of the fluid domain of the three-period minimal surface structure varies continuously in a gradient along the direction from the suction side of the turbine blade to the pressure side of the turbine blade; the three-period minimal surface structure has a relatively large equivalent aperture near the suction side of the turbine blade; the three-period minimal surface structure has a relatively small equivalent aperture near the pressure side of the turbine blade; and there is a gradient region with a smooth transition between the suction side and the pressure side of the turbine blade.

[0013] In one possible implementation of the second aspect, the three-period minimal surface structure is any one of a Gyroid surface, a Diamond surface, a Primitive surface, a Schwarz P surface, or a Schwarz D surface.

[0014] In one possible implementation of the second aspect, the cell size of the three-period minimal surface structure is determined according to the size of the cooling cavity, and a predetermined number of cells are arranged in the length, width, and height directions of the cooling cavity.

[0015] In one possible implementation of the second aspect, the wall thickness of the solid domain of the three-period minimal surface structure is not less than 0.3 mm.

[0016] In one possible implementation of the second aspect, the three-period minimal surface structure and the turbine blade body are integrally formed by additive manufacturing technology, and the three-period minimal surface structure and the turbine blade body are an integrated structure with metallurgical bonding.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: This invention provides a turbine blade cooling channel design method based on a three-period minimal curved surface structure. By using the physical characteristics of the rotating centrifugal force field as the design input, it fundamentally solves the problem of uneven cooling medium distribution under high-speed rotation conditions. Specifically, the method first analyzes the cooling medium distribution characteristics caused by centrifugal force, and determines the gradient design direction and the variation law of key parameters accordingly. This allows the generated TPMS structure to actively compensate for the flow distortion caused by centrifugal force, achieving flow field adaptation at the physical mechanism level. This makes the distribution of cooling medium on the suction and pressure sides more balanced, avoiding local high-temperature points caused by uneven flow. This design method adopts a collaborative design of gradient design and geometric mapping, solving two different levels of technical problems: physical field adaptation and geometric shape adaptation. The TPMS structure is pre-assigned gradient features in a regular parameter space, and then fitted to an irregular cavity through geometric transformation methods. This ensures that the gradient features are completely preserved during complex deformation. The final generated three-dimensional design model can perfectly fit the inner wall of the blade cavity and maintain the preset aperture variation law from the suction to the pressure side.

[0018] This invention provides a turbine blade based on a three-period minimal surface structure. By incorporating a three-period minimal surface structure with a continuous gradient of equivalent orifice diameter along the direction from the suction surface to the pressure surface within the cooling chamber, active adaptation to the rotating centrifugal force field is achieved. The relatively largest equivalent orifice diameter is positioned near the suction surface, resulting in lower flow resistance and guiding more cooling medium into the previously insufficient flow area. Conversely, the relatively smallest equivalent orifice diameter is positioned near the pressure surface, resulting in higher flow resistance and suppressing the accumulation of excess cooling medium. This invention achieves a more balanced distribution of cooling medium within the blade, fundamentally solving the problem of excessive flow on the pressure surface and insufficient cooling on the suction surface caused by high-speed rotation. The three-period minimal surface structure in the turbine blade of this invention features a smoothly transitioning gradient region, avoiding flow disturbances caused by abrupt changes in orifice diameter. From the suction side to the pressure side, the equivalent aperture continuously and smoothly decreases from large to small, allowing the cooling medium to transition smoothly when flowing through different areas. This prevents additional flow losses or secondary flows caused by sudden changes in the flow channel cross-section, ensuring uniform distribution of the cooling medium while maintaining the inherent low flow resistance characteristics of the three-period minimal curved surface structure.

[0019] The turbine blade of this invention utilizes a three-period minimal curved surface structure with gradient characteristics as a cooling channel, fully leveraging the high specific surface area advantage of the TPMS structure. When the cooling medium flows through this structure, the heat transfer area between it and the solid domain is significantly larger than that of a traditional serpentine channel, enabling more efficient convective heat transfer within the same volume. Simultaneously, the gradient aperture design ensures a more uniform distribution of the cooling medium, effectively cooling the entire wall area of ​​the cooling chamber and preventing the formation of localized high-temperature points, thereby extending the service life of the turbine blade under extreme high-temperature environments. Unlike traditional serpentine channels that generate flow separation and secondary flow at bends, the TPMS structure features a naturally continuous and smooth flow path, resulting in minimal pressure loss as the cooling medium flows within it. This allows for the consumption of less high-pressure cooling gas while achieving the same cooling effect, contributing to improved overall engine efficiency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a turbine blade cooling channel design method based on a three-period minimal surface structure according to the present invention.

[0022] Figure 2 (a) shows a schematic diagram of a representative internal cooling fluid domain in the chord region of a turbine rotor blade; Figure 2 (b) in the figure is a close-up of the three-dimensional geometry of the fluid domain, and its shape reflects the typical irregularity of the turbine blade cavity in order to adapt to the aerodynamic shape and structural load-bearing requirements. Figure 2 (c) shows a customized three-period minimal surface structure model that perfectly fits the cooling cavity, generated using the design method of the present invention.

[0023] Figure 3 (a) shows an initial three-period minimal surface structure model with pre-defined gradient features generated in the regular parameter space; Figure 3 (b) in the figure intuitively presents the mapping result, namely a three-period minimal surface filler that perfectly fits the inner wall of the turbine blade and completely maintains the preset gradient distribution characteristics from the suction surface to the pressure surface.

[0024] Figure 4 This is a schematic diagram showing the gradient characteristics of the three-period minimal surface parameterization model of the present invention in a regular parameter space. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, this invention provides a method for designing cooling channels for turbine blades based on a three-period minimal curved surface structure. This method constructs cooling channels within the internal cooling cavity of the turbine blade, specifically addressing the problem of uneven cooling medium distribution caused by centrifugal force on aerospace engine turbine blades under high-speed rotation. The mid-chord region of the turbine blade is typically designed with a continuous internal cooling cavity. The method specifically includes the following steps: S1. Based on the rotational condition of the turbine blade, analyze the distribution characteristics of the cooling medium in the cooling cavity caused by centrifugal force. Define the direction from the suction side of the turbine blade to the pressure side of the turbine blade as the gradient design direction. Based on the distribution characteristics, determine the variation law of the key parameters controlling the geometric features of the three-period minimal surface structure along the gradient design direction.

[0027] In practice, computational fluid dynamics (CFD) simulations are performed on the original smooth cooling channel of the turbine blade under rotating conditions to obtain the velocity distribution of the cooling medium across the channel cross-section. For example, the simulation results show that, under centrifugal force, the average velocity on the pressure side is approximately 2.2 times that on the suction side. This velocity difference directly reflects the non-uniformity of the cooling medium distribution. Based on this analysis, the direction from the suction side to the pressure side of the turbine blade is defined as the gradient design direction, denoted as... s The direction is determined, and four complete three-period minimal surface cells are planned and distributed along this direction based on the actual thickness of the cooling channel. Based on the distribution characteristics, the variation law of the key parameters controlling the geometric characteristics of the three-period minimal surface structure along the gradient design direction is determined. To compensate for this velocity difference and promote flow rebalancing, the goal is to provide a larger flow channel aperture on the suction side and a smaller flow channel aperture on the pressure side. According to fluid dynamics principles such as the Darcy-Wiesbach equation, in turbulent flow, the flow pressure drop is related to the negative power of the hydraulic diameter. As an engineering approximation, the target flow resistance can be set to be inversely proportional to the target flow velocity to tend towards uniform flow distribution.

[0028] S2. Within the regular parameter space, the generation process of the three-period minimal surface is controlled according to the change law, so that the local geometric features of the three-period minimal surface change accordingly with the change of the position of the local geometric feature along the gradient design direction, thereby generating a parameterized model of the three-period minimal surface with predetermined gradient features in the parameter space.

[0029] Specifically, first, in the nTopology advanced modeling software, a field variable is created, the value of which is calculated based on a defined variation law. Then, in the software's built-in TPMS module, a three-period minimum surface type is selected, and a threshold parameter, typically a constant, is associated with the field variable created above. The software generates the geometric properties of each calculation point in real time based on the field variable value. After executing the generation command, a parametric model of a three-period minimum surface with predetermined gradient characteristics in the parameter space is obtained. For example... Figure 4 As shown, the three-period minimal surface parameterization model has intuitively exhibited gradient characteristics within the regular parameter space: the structure is loose and the pore size is large on the suction side; the structure is dense and the pore size is small on the pressure side.

[0030] S3. Using a geometric transformation method, the three-period minimal surface parameterized model is transformed as a whole and fitted into the three-dimensional physical space of the turbine blade cooling cavity, generating a three-dimensional design model that fits the inner wall of the cooling cavity and maintains the gradient characteristics.

[0031] Specifically, the generated gradient parameterized model is transformed using a geometric transformation algorithm to map the coordinates and material properties of each point in the parameter space to their corresponding positions in the physical space. This process ensures that the deformed structure (such as...) Figure 3 As shown in (b), it can perfectly fit the complex curved surface of the turbine blade cavity and strictly maintain the aperture change law from the suction surface to the pressure surface, and finally generate a three-dimensional design model that fits the inner wall of the cooling cavity and maintains the gradient characteristics.

[0032] like Figure 2 As shown, Figure 2 (a) shows a schematic diagram of a representative internal cooling fluid domain in the chord region of a turbine rotor blade. Figure 2 (b) in the figure is a close-up of the three-dimensional geometry of the fluid domain, and its shape reflects the typical irregularity of the turbine blade cavity to adapt to the aerodynamic shape and structural load requirements. Figure 2 (c) shows a customized three-period minimal surface structure model that perfectly fits the cooling cavity, generated using the design method of the present invention.

[0033] In this invention, the three-period minimal surface structure is not a uniform design, but rather a variable gradient structure oriented towards rotating conditions. Specifically, under the action of a high-speed rotating centrifugal force field, the cooling medium will accumulate from the suction side to the pressure side, resulting in excess flow on the pressure side and insufficient cooling on the suction side. To actively compensate for this physical effect, the three-period minimal surface structure designed in this invention features a continuous gradient change in the equivalent aperture of its fluid domain along the direction from the suction side to the pressure side of the blade: on the side closer to the suction side, the structure has a relatively large equivalent aperture to reduce flow resistance and guide more cooling medium to flow in; on the side closer to the pressure side, the structure has a relatively small equivalent aperture to increase flow resistance and suppress excess cooling medium; in between is a smoothly transitioning gradient region. This variable gradient design enables a more uniform distribution of the cooling medium in a complex rotating force field, thereby fundamentally improving the uniformity of blade cooling.

[0034] It should be understood that the three-period minimal surface structure consists of a continuous, self-supporting porous skeleton network formed by its solid domains, and the interconnected pores within this skeleton network form a single fluid channel for the flow of cooling gas.

[0035] It should be noted that the solid domain of the three-period minimal surface structure in this invention refers to the main material portion constituting the porous skeleton network. This portion is designed with a specific three-period minimal surface shape to maximize the heat transfer area and guide the fluid. The solid domain material must possess high thermal conductivity, excellent high-temperature resistance, and creep resistance to adapt to the extreme working environment of the turbine blade. Therefore, high-performance metal alloys, such as nickel-based superalloys, are typically selected. For example, the turbine blade body is integrally formed using GH4586 alloy through additive manufacturing technology. GH4586 alloy has extremely high high-temperature strength, good oxidation resistance, and hot corrosion resistance, ensuring long-term stable operation of the blade in a high-temperature combustion gas environment. The internal cooling cavity and the three-period minimal surface structure filling it are integral parts of the blade body from the design and modeling stage. During manufacturing, GH4586 alloy powder is melted and solidified layer by layer using technologies such as laser powder bed melting, thereby directly manufacturing an integrated component where the three-period minimal surface structure is metallurgically bonded to the blade body.

[0036] In one possible implementation, the key parameter is a threshold parameter that controls the size of the three-period minimal surface fluid domain. The variation law is constructed such that the threshold parameter has a minimum value on the turbine blade suction side and a maximum value on the turbine blade pressure side, and changes continuously and monotonically between the turbine blade suction side and the turbine blade pressure side, so that the equivalent aperture of the fluid domain of the three-period minimal surface structure decreases continuously from the turbine blade suction side to the turbine blade pressure side.

[0037] Specifically, for the selected three-period minimum surface, its implicit equation threshold constant is... C Constructed as a function along the thickness direction C(s) Set on the suction side ( s =0), C Take the minimum value The maximum aperture corresponds to the maximum aperture; on the pressure side (s=1), C takes its maximum value. This corresponds to the minimum aperture. Through this construction, the equivalent aperture of the fluid domain of the three-period minimal surface structure decreases continuously in a gradient from the suction side of the turbine blade to the pressure side of the turbine blade.

[0038] For example, the three-period minimum surface is a Gyroid surface. To achieve flow resistance compensation corresponding to an approximately 2.2-fold increase in flow velocity from the suction surface to the pressure surface, the geometric characteristics of the Gyroid surface and empirical correlations can be used to determine... / The ratio ranges from approximately 1.5 to 2.0. In this example, we take... =0.4, =0.7. The gradient change uses a power function form for a smooth transition, ensuring that the function is continuously and monotonically increasing within the interval.

[0039] In one possible implementation, the law of change is expressed in functional form:

[0040] in, Normalized coordinates are used along the direction from the suction side of the turbine blade to the pressure side of the turbine blade. for Threshold parameter value at the location, and They are respectively s =0 and s The threshold parameter value at =1; Let be a function that is continuously and monotonically increasing in the interval [0,1].

[0041] In this specific example, take = s 1.5 Thus, the specific gradient control function is obtained: This function ensures that, within the parameter space, along the gradient design direction, the fluid domain size of the three-period minimum surface structure transitions continuously and smoothly from maximum on the suction side to minimum on the pressure side.

[0042] In one possible implementation, the geometric transformation method is an isoparametric mapping method, which uses shape functions to transform between parametric space coordinates and physical space coordinates.

[0043] Specifically, this is achieved through the following relational expression:

[0044] in, For parameter space coordinates, These are physical space coordinates, i.e., real coordinates; A shape function defined in parameter space, used to interpolate nodal coordinates to determine the physical location of any point within the element; The node coordinates define the physical shape of the space. This isoparametric mapping method precisely maps the gradient parameterized model generated in S2 to the physical space of the turbine blade cavity, ensuring that the deformed structure conforms to the complex surface while strictly maintaining the preset gradient characteristics.

[0045] In one possible implementation, after generating a three-dimensional design model that fits the inner wall of the cooling cavity and maintains the gradient features, the method further includes: converting the three-dimensional design model into a data format recognizable by the additive manufacturing equipment for manufacturing turbine blades.

[0046] In practice, the final 3D model obtained after mapping is meshed and its file format is converted, exported to a standardized format suitable for laser powder bed melting equipment, such as .stl format. For example, GH4586 high-performance nickel-based high-temperature alloy powder is selected as the material, and reasonable process parameters are set for integrated additive manufacturing. This integrated manufacturing method fundamentally eliminates the interface contact thermal resistance and sealing problems that may exist in traditional assembly. During the manufacturing process, high-temperature alloy powder is melted and solidified layer by layer using technologies such as laser powder bed melting, directly manufacturing an integrated component with a three-period minimal curved surface structure and the blade body in a metallurgical bond. After manufacturing, stress-relief annealing and necessary post-processing are performed to eliminate residual stress and ensure material properties. To ensure smooth cooling gas flow and heat exchange effect, the inner surface of the three-period minimal curved surface flow channel is smoothed through subsequent processes to reduce flow resistance and maintain preset geometric characteristics, ultimately obtaining a turbine blade component integrating an adaptive variable gradient cooling channel for rotating conditions.

[0047] This invention provides a turbine blade based on a three-period minimal surface structure, manufactured using the design method described in the preceding embodiments. The turbine blade includes a turbine blade body, within which a cooling cavity is formed. This cooling cavity is filled with a three-period minimal surface structure, and the interconnecting pores of the three-period minimal surface structure constitute cooling fluid channels. The equivalent aperture of the fluid domain of the three-period minimal surface structure exhibits a continuous gradient change along the direction from the suction side to the pressure side of the turbine blade. Near the suction side, the three-period minimal surface structure has a relatively large equivalent aperture; near the pressure side, it has a relatively small equivalent aperture. A smooth gradient region exists between the suction side and the pressure side of the turbine blade.

[0048] This structural feature allows the cooling gas to be fully disturbed in the high specific surface area and highly interconnected mesh channels to enhance heat transfer when it flows through the structure. More importantly, the gradient channels designed along the suction surface to the pressure surface can actively adjust the local flow resistance and effectively compensate for the natural distribution gradient of the cooling medium caused by the centrifugal force of high-speed rotation.

[0049] like Figure 3 As shown, Figure 3 (a) shows an initial three-period minimal surface structure model (using the Gyroid surface as an example) with pre-defined gradient features generated in the regular parameter space. Its fluid domain size has shown a continuous gradient change from one side of the model (representing the suction side of the blade) to the other side (representing the pressure side). Figure 3 (b) in the figure intuitively presents the mapping result, namely a customized three-period minimal surface filler that perfectly fits the inner wall of the turbine blade and completely maintains the preset gradient distribution characteristics from the suction surface to the pressure surface.

[0050] For example, the turbine blade body is integrally formed using GH4586 alloy through additive manufacturing technology. The internal cooling cavity and the three-period minimal curved surface structure filling it are integral parts of the blade body from the design and modeling stage. During manufacturing, GH4586 alloy powder is melted and solidified layer by layer using technologies such as laser powder bed melting, thereby directly manufacturing an integrated component where the three-period minimal curved surface structure is metallurgically bonded to the blade body. GH4586 alloy possesses extremely high high-temperature strength, good oxidation resistance, and hot corrosion resistance, ensuring long-term stable operation of the blade in high-temperature combustion gas environments. In other alternative embodiments, other grades of nickel-based or cobalt-based high-temperature alloys can be selected according to specific operating temperature and load requirements.

[0051] In one possible implementation, the three-period minimal surface structure is any one of a Gyroid surface, a Diamond surface, a Primitive surface, a Schwarz P surface, or a Schwarz D surface.

[0052] In this embodiment, the three-period minimum surface structure is a Gyroid surface. Gyroid surfaces possess high symmetry and continuous channel characteristics, providing a large specific surface area per unit volume, and their smooth, continuous flow channels make them ideal for enhancing convective heat transfer and reducing flow resistance. In other alternative embodiments, depending on specific heat transfer and strength requirements, the three-period minimum surface structure can also be any one of a Diamond surface, Primitive surface, Schwarz P surface, or Schwarz D surface. Different surface types have different topological characteristics, adaptable to different heat transfer and flow requirements.

[0053] In one possible implementation, the cell size of the three-period minimal surface structure is determined according to the size of the cooling cavity, and a predetermined number of cells are arranged in the length, width, and height directions of the cooling cavity.

[0054] Specifically, considering the dimensional characteristics of the chordal cooling channels in turbine blades, the number of cells in the three-period minimal surface structure is planned accordingly. For example, for a filling region with dimensions of 10mm high, 5mm long, and 2.5mm wide, 3, 2, and 5 cells can be arranged in the length, width, and height directions, respectively. It should be understood that determining the cell size requires multi-objective optimization combining computational fluid dynamics and heat transfer simulation to achieve the optimal comprehensive balance between heat transfer and flow performance while satisfying structural strength requirements.

[0055] In one possible implementation, the wall thickness of the solid domain of the three-period minimal surface structure is not less than 0.3 mm.

[0056] Specifically, considering the enormous centrifugal force, aerodynamic load, and thermal stress that turbine blades endure under high-speed rotation, the solid domain wall thickness δ of the three-period minimal curved surface structure is a critical design parameter. The wall thickness must ensure the structure's strength and durability under extreme conditions. As a preferred starting point, the wall thickness δ should be no less than 0.3 mm. In practical design, finite element analysis is needed to verify the stress level under the coupled effects of centrifugal and thermal loads, and the wall thickness should be finely adjusted accordingly to achieve lightweight design while meeting strength requirements.

[0057] This invention provides an application of a turbine blade cooling channel based on a variable gradient three-period minimal surface structure, applied to the internal cooling system of high-speed rotating aero-engine turbine rotor blades. In use, the interconnected pores of the three-period minimal surface structure with a pore size gradient, filling the chordal cooling channel of the turbine blade, serve as a single cooling fluid channel for introducing cooling gas. As the cooling gas flows through the structure, it is sufficiently agitated within its highly interconnected mesh-like flow channels to enhance heat transfer. The gradient flow channels designed along the suction side to the pressure side actively adjust local flow resistance, effectively compensating for the natural distribution gradient of the cooling medium caused by the centrifugal force of high-speed rotation. This allows the cooling gas to be guided and redistributed even in a strong centrifugal force field, achieving more uniform coverage and heat transfer across the entire inner wall of the cooling channel, significantly reducing the blade wall temperature gradient, and fundamentally suppressing the formation of local high-temperature regions. Simultaneously, the inherent smooth and continuous flow channel characteristics of this structure help maintain a low overall flow pressure drop, thereby improving the overall efficiency of the cooling system.

[0058] In summary, this invention solves the shape fitting problem of the three-period minimal surface structure in the irregular internal cavity of a turbine blade, as well as the problem of uneven flow distribution of the three-period minimal surface structure under rotating conditions, through variable gradient design and geometric adaptation methods oriented towards rotating physical fields. This invention combines the excellent heat transfer characteristics of the three-period minimal surface with the physical requirements of rotating conditions, providing a synergistically improved solution for turbine blade cooling that combines high-efficiency heat exchange, extreme uniformity, low flow resistance, and lightweight design.

[0059] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] 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.

[0064] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention.

Claims

1. A method for designing cooling channels for turbine blades based on a three-period minimal surface structure, used to construct cooling channels within the internal cooling cavity of the turbine blade, characterized in that... include: Based on the rotational conditions of the turbine blades, the distribution characteristics of the cooling medium caused by centrifugal force in the cooling cavity are analyzed. The direction from the suction side to the pressure side of the turbine blade is defined as the gradient design direction. Based on the distribution characteristics, the variation law of the key parameters controlling the geometric features of the three-period minimal surface structure along the gradient design direction is determined. Within the regular parameter space, the generation process of the three-period minimal surface is controlled according to the change law, so that the local geometric features of the three-period minimal surface change accordingly with the change of the location of the local geometric features along the gradient design direction, thereby generating a parameterized model of the three-period minimal surface with predetermined gradient features in the parameter space. By using geometric transformation methods, the three-period minimal surface parameterized model is transformed as a whole and fitted into the three-dimensional physical space of the turbine blade cooling cavity, generating a three-dimensional design model that fits the inner wall of the cooling cavity and maintains the gradient characteristics.

2. The turbine blade cooling channel design method based on a three-period minimal curved surface structure according to claim 1, characterized in that, The key parameter is a threshold parameter that controls the size of the fluid domain of the three-period minimal surface. The variation law is constructed such that the threshold parameter has the minimum value on the turbine blade suction side and the maximum value on the turbine blade pressure side, and changes continuously and monotonically between the turbine blade suction side and the turbine blade pressure side, so that the equivalent aperture of the fluid domain of the three-period minimal surface structure decreases continuously from the turbine blade suction side to the turbine blade pressure side.

3. The turbine blade cooling channel design method based on a three-period minimal curved surface structure according to claim 2, characterized in that, The pattern of change can be expressed in functional form: in, Normalized coordinates are used along the direction from the suction side of the turbine blade to the pressure side of the turbine blade. for Threshold parameter value at the location, and They are respectively s =0 and s The threshold parameter value at =1; Let be a function that is continuously and monotonically increasing in the interval [0,1].

4. The turbine blade cooling channel design method based on a three-period minimal curved surface structure according to claim 1, characterized in that, The geometric transformation method is an isoparametric mapping method, which uses shape functions to transform between parametric space coordinates and physical space coordinates.

5. The turbine blade cooling channel design method based on a three-period minimal curved surface structure according to claim 1, characterized in that, After generating the three-dimensional design model that fits the inner wall of the cooling cavity and maintains the gradient features, the method further includes: The three-dimensional design model is converted into a data format recognizable by additive manufacturing equipment for the manufacture of turbine blades.

6. A turbine blade based on a three-period minimal surface structure, comprising a turbine blade body, wherein a cooling cavity is disposed inside the turbine blade body, the cooling cavity is filled with a three-period minimal surface structure, and the interconnecting pores of the three-period minimal surface structure constitute cooling fluid channels, characterized in that... The equivalent aperture of the fluid domain of the three-period minimal surface structure exhibits a continuous gradient change along the direction from the suction side to the pressure side of the turbine blade; the three-period minimal surface structure has a relatively large equivalent aperture near the suction side of the turbine blade; and it has a relatively small equivalent aperture near the pressure side of the turbine blade; there is a smooth gradient region between the suction side and the pressure side of the turbine blade.

7. A turbine blade based on a three-period minimal surface structure according to claim 6, characterized in that, The three-period minimal surface structure is any one of the following: Gyroid surface, Diamond surface, Primitive surface, Schwarz P surface, or Schwarz D surface.

8. A turbine blade based on a three-period minimal surface structure according to claim 6, characterized in that, The cell size of the three-period minimal surface structure is determined according to the size of the cooling cavity, and a preset number of cells are arranged in the length, width and height directions of the cooling cavity.

9. A turbine blade based on a three-period minimal surface structure according to claim 6, characterized in that, The wall thickness of the solid domain of the three-period minimal surface structure is not less than 0.3 mm.

10. A turbine blade based on a three-period minimal surface structure according to claim 6, characterized in that, The three-cycle minimal curved surface structure and the turbine blade body are integrally formed by additive manufacturing technology, and the three-cycle minimal curved surface structure and the turbine blade body are an integrated structure with metallurgical bonding.

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