A turbine vane temperature gradient crack propagation test method

Abstract

The present application belongs to the technical field of aero-engine, and particularly relates to a turbine guide vane temperature gradient crack propagation test method, which comprises determining a dangerous position of a real turbine guide vane; simulating the real turbine guide vane to obtain a first change rule of a stress intensity factor on a crack propagation path of the dangerous position; simultaneously acting on a simulation structure of the turbine guide vane through a plurality of independent electromagnetic induction heating modules and a plurality of cooling modules, so that the dangerous position of the simulation structure has a temperature gradient consistent with that of the real turbine guide vane; carrying out a crack propagation test to obtain a second change rule of the stress intensity factor on the crack propagation path of the dangerous position; comparing the first change rule and the second change rule; if the first change rule is consistent with the second change rule, ending the crack propagation test; and if the first change rule is inconsistent with the second change rule, adjusting a displacement load applied on the simulation structure. The present application improves the accuracy of obtained test data.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine technology, specifically relating to a test method for temperature gradient crack propagation in turbine guide vanes. Background Technology

[0002] Turbine guide vanes (such as turbine blades and combustion chamber walls) of aero-engines operate under extremely harsh conditions for extended periods during service. These components typically bear the combined effects of high temperatures, high stresses, and significant thermal gradient loads. These complex conditions not only exacerbate degradation mechanisms such as high-temperature creep, fatigue damage, and oxidation corrosion of materials, but also significantly influence crack initiation and propagation behavior. Therefore, it is necessary to conduct crack propagation tests on turbine guide vanes.

[0003] During service, turbine guide vanes operate in a non-uniform temperature gradient heating environment. However, existing crack propagation testing devices mostly employ uniform heating (such as integral furnace heating or radiation heating), and the loading method is typically uniaxial loading. This fails to accurately reproduce the non-uniform, multi-physics coupled environment experienced by turbine guide vanes under actual service conditions. This simplified loading and heating method significantly limits the representativeness and engineering reference value of the test data.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] To improve the accuracy of experimental data obtained from crack loading tests, thereby enhancing the representativeness and engineering reference value of the data, this invention provides a method for testing the temperature gradient crack propagation of turbine guide vanes.

[0006] This invention includes the following technical solutions:

[0007] This invention provides a method for testing the temperature gradient crack propagation of turbine guide vanes, comprising the following steps:

[0008] Identify the critical areas of the actual turbine guide vanes;

[0009] Simulation was performed on a real turbine guide vane to obtain the first variation law of stress intensity factor on the crack propagation path of the critical part;

[0010] By simultaneously applying multiple independent electromagnetic induction heating modules and multiple cooling modules to the simulated structure of the turbine guide vane, the dangerous parts of the simulated structure have the same temperature gradient as the real turbine guide vane.

[0011] Crack propagation tests were conducted to obtain the second variation law of stress intensity factor along the crack propagation path in the critical area;

[0012] Compare the first and second variation patterns: if the first variation pattern is consistent with the second variation pattern, the crack propagation test is terminated; if the first variation pattern is inconsistent with the second variation pattern, the displacement load applied to the simulated structure is adjusted until the first variation pattern is consistent with the second variation pattern.

[0013] Furthermore, identifying the critical locations of the turbine guide vanes includes the following steps:

[0014] Obtain the geometric model, material properties, and typical operating conditions of the turbine guide vane;

[0015] Static strength analysis of turbine guide vane structure was carried out using geometric model, material property parameters and typical working conditions to obtain the magnitude and direction of the maximum principal stress of turbine guide vane.

[0016] The location of the maximum principal stress on the turbine guide vane is the critical area.

[0017] Furthermore, the material performance parameters include the material's density, elastic modulus, Poisson's ratio, coefficient of linear expansion, and thermal conductivity.

[0018] Furthermore, simulations were performed on the turbine guide vane to obtain the first variation law of the stress intensity factor along the crack propagation path in the critical area, including the following steps:

[0019] A turbine guide vane model was constructed using crack propagation analysis software.

[0020] Initial cracks are set at dangerous locations on the turbine guide vane model; material property parameters and crack propagation model parameters are set.

[0021] Simulation calculations were performed to extract the first variation law of stress intensity factor along the crack propagation path.

[0022] Furthermore, by simultaneously applying multiple independent electromagnetic induction heating modules and multiple cooling modules to the simulated structure of the turbine guide vane, a temperature gradient is created in the hazardous areas of the simulated structure, including the following steps:

[0023] Multiple sets of independent electromagnetic induction heating modules and multiple cooling modules are arranged on the simulation structure;

[0024] The electromagnetic induction heating module and cooling module operate to obtain the real-time temperature of the dangerous parts of the simulated structure;

[0025] The output power of the electromagnetic induction heating module is controlled according to the real-time temperature until the dangerous parts of the simulated structure have a temperature gradient consistent with that of the real turbine guide vanes.

[0026] Furthermore, the simulated structure is an I-shaped uniaxial eccentric tension member.

[0027] Furthermore, the geometric dimensions, shape, upper edge transition radius, and lower edge transition radius of the turbine guide vane edge plate in the simulated structure are consistent with those of the turbine guide vane.

[0028] Furthermore, the material of the simulated structure is selected based on preset electrical conductivity, preset magnetic permeability, preset thermal conductivity, and preset specific heat capacity.

[0029] Furthermore, the electromagnetic induction heating module is an electromagnetic coil.

[0030] Furthermore, the electromagnetic coil is helical.

[0031] By adopting the above technical solution, the present invention has the following advantages:

[0032] 1. The method of the present invention improves the accuracy of the test data obtained from crack loading tests, and has the advantage of improving the representativeness and engineering reference value of the test data.

[0033] 2. The method of the present invention can obtain a simulated structure with a temperature gradient consistent with that of a real turbine blade, which breaks through the limitations of a uniform temperature field and can accurately simulate the crack propagation behavior of hot-end components of aero-engines under extreme temperature gradients, providing a reliable experimental means for damage tolerance assessment of high-temperature materials.

[0034] 3. This invention uses crack propagation analysis software to simulate the real structure of a turbine guide vane, calculates the critical crack size, extracts the stress intensity factor variation law on the crack propagation path, designs an I-shaped single-axis eccentric tensile simulation structure, and retains key geometric dimensions.

[0035] 4. This invention employs a variable amplitude loading method (by adjusting the loading displacement of the simulated structure) to ensure that the crack propagation path and stress intensity factor dynamically match the actual working conditions, making the stress intensity factor of the simulated structure consistent with that of the real structure. This solves the problem that traditional uniaxial tensile loading simulations do not fully simulate the variation of the stress intensity factor with crack length in real structures.

[0036] 5. This invention combines electromagnetic induction heating and ventilation cooling to form a controllable high temperature gradient field on the surface of the simulated structure, accurately simulating the actual working conditions of the turbine guide vane of an aero-engine.

[0037] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0038] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings.

[0039] Figure 1 The following is a flowchart of a turbine guide vane temperature gradient crack propagation test method in an embodiment of the present invention. Figure 1 ;

[0040] Figure 2 The following is a flowchart of a turbine guide vane temperature gradient crack propagation test method in an embodiment of the present invention. Figure 2 . Detailed Implementation

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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 based on these drawings without creative effort.

[0042] The following description provides many different embodiments or examples for implementing various features of the invention. The elements and arrangements described in the specific examples below are only for concise expression of the invention and are merely examples, not intended to limit the invention.

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments 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.

[0044] This embodiment provides a method for testing the temperature gradient crack propagation of turbine guide vanes, such as... Figure 1 As shown, it includes the following steps:

[0045] Identify the critical areas of the actual turbine guide vanes;

[0046] Simulation was performed on a real turbine guide vane to obtain the first variation law of stress intensity factor on the crack propagation path of the critical part;

[0047] By simultaneously applying multiple independent electromagnetic induction heating modules and multiple cooling modules to the simulated structure of the turbine guide vane, the dangerous parts of the simulated structure have the same temperature gradient as the real turbine guide vane.

[0048] Crack propagation tests were conducted to obtain the second variation law of stress intensity factor along the crack propagation path in the critical area;

[0049] Compare the first and second variation patterns: if the first variation pattern is consistent with the second variation pattern, the crack propagation test is terminated; if the first variation pattern is inconsistent with the second variation pattern, the displacement load applied to the simulated structure is adjusted until the first variation pattern is consistent with the second variation pattern.

[0050] The geometric model, material properties, and typical operating conditions of the turbine guide vane are obtained. The location of the maximum first principal stress is determined as the critical location through thermo-solid coupled load analysis, and the initial crack plane is selected.

[0051] In some embodiments, determining the critical location of the turbine guide vane includes the following steps:

[0052] Obtain the geometric model, material properties, and typical operating conditions of the turbine guide vane;

[0053] Static strength analysis of turbine guide vane structure is carried out using geometric model, material performance parameters and typical working conditions. That is, the static strength analysis of turbine guide vane structure is carried out based on the thermo-solid coupled load characteristics of turbine guide vane under typical working conditions, and the magnitude and direction of the maximum principal stress of turbine guide vane are obtained.

[0054] The location of the maximum principal stress on the turbine guide vane is the critical area.

[0055] In some embodiments, the material performance parameters include the material's density, elastic modulus, Poisson's ratio, coefficient of linear expansion, and thermal conductivity.

[0056] In some embodiments, simulation is performed on the turbine guide vane to obtain the first variation law of the stress intensity factor along the crack propagation path at the critical location, including the following steps:

[0057] A turbine guide vane model was constructed using crack propagation analysis software.

[0058] Initial cracks are set at dangerous locations on the turbine guide vane model; material property parameters and crack propagation model parameters are set.

[0059] Simulation calculations were performed to extract the first variation law of stress intensity factor along the crack propagation path.

[0060] In some embodiments, applying multiple independent electromagnetic induction heating modules and multiple cooling modules simultaneously to the simulated structure of the turbine guide vane to create a temperature gradient in the hazardous areas of the simulated structure includes the following steps:

[0061] Multiple sets of independent electromagnetic induction heating modules and multiple cooling modules are arranged on the simulation structure;

[0062] The electromagnetic induction heating module and cooling module operate to obtain the real-time temperature of the dangerous parts of the simulated structure;

[0063] The output power of the electromagnetic induction heating module is controlled according to the real-time temperature until the dangerous parts of the simulated structure have a temperature gradient consistent with that of the real turbine guide vanes.

[0064] In some embodiments, the simulated structure is an I-shaped uniaxial eccentric tension member.

[0065] In some embodiments, the geometric dimensions, shape, upper edge transition radius, and lower edge transition radius of the turbine guide vane edge plate in the simulated structure are consistent with those of the turbine guide vane.

[0066] In some embodiments, the material of the simulated structure is selected based on preset electrical conductivity, preset magnetic permeability, preset thermal conductivity, and preset specific heat capacity.

[0067] In some embodiments, the electromagnetic induction heating module is an electromagnetic coil.

[0068] In some embodiments, the electromagnetic coil is helical.

[0069] Based on the method of this invention, exemplarily:

[0070] like Figure 2 As shown, the geometric model, material properties, and typical operating conditions of the turbine guide vane are obtained. Based on the thermo-solid coupled load characteristics in the typical operating conditions of the turbine guide vane, a real structural static strength analysis is carried out on the turbine guide vane to obtain the magnitude and direction of the maximum principal stress of the structure. The location of the maximum principal stress is identified as the critical location. The stress gradient of the critical location is obtained, and the plane perpendicular to the maximum principal stress is selected as the initial crack plane.

[0071] Using crack propagation analysis software, a turbine guide vane was simulated. An initial crack was assumed to exist at a critical location. The required material parameters and crack propagation model parameters were set, and the critical crack size at the critical location was calculated. This critical crack size represents the crack dimension in the depth direction. The stress intensity factor variation law (i.e., the second variation law) along the crack propagation path was extracted, and the geometric dimensions that mainly affect the stress intensity factor along the crack propagation path were determined. To ensure that the key geometric dimensions remain unchanged and to better simulate the real tensile-bending coupling load of the turbine guide vane, the simulation structure was designed as an I-shaped single-axis eccentric tension member. The bearing section of the simulation structure is a pin hole. The key dimensions of the simulation structure include the geometric dimensions of the turbine guide vane edge plate, the geometric shape of the turbine guide vane edge plate, the transition angle radius of the upper edge plate, and the transition angle radius of the lower edge plate. The selected crack propagation model is the Paris formula.

[0072]

[0073] In the formula, C is the material constant, a is the crack length, N represents the number of cycles, da represents the differential of the crack length, and dN represents the differential of the number of cycles. ΔK represents the amount of crack length *a* that extends after each load cycle, and ΔK is the difference between the maximum and minimum stress intensity factor defined within the stress intensity factor range (ΔK = K). max -K min C reflects the material's resistance to fatigue crack propagation, and n represents the sensitivity of the crack propagation rate to the range of stress intensity factors.

[0074] Considering that turbine guide vanes bear large mechanical loads and also have high temperature gradients, under high temperature gradients, the mismatch of thermal expansion coefficients in different regions of the material due to temperature differences leads to high stress concentration inside, which may cause crack initiation and propagation. Therefore, electromagnetic-thermal-structure interaction simulation is performed using simulation software to obtain the real temperature gradient of the turbine guide vane.

[0075] Multiple independent electromagnetic induction heating modules are used. Appropriate electromagnetic coil shapes are selected, the required material properties are set, heat transfer boundary conditions are set, the parameters of the ventilation cooling module are determined, the non-heated parts of the simulated structure are covered, and the flow rate and direction of the cooling gas in the cooling module, as well as the coverage area of ​​the cooling gas, are adjusted to ensure that the temperature gradient of the simulated structure in a crack-free state is consistent with the real temperature gradient.

[0076] By setting the loading method to displacement loading, a crack propagation test was conducted on the simulated structure to obtain the stress intensity factor variation law (i.e., the second variation law) on the crack propagation path of the critical part.

[0077] Compare the first and second variation patterns: if the first variation pattern is consistent with the second variation pattern, then end the crack propagation test; if the first variation pattern is inconsistent with the second variation pattern, then adjust the displacement load applied to the simulated structure (adjust the magnitude of the loading displacement according to the change of crack length so that the stress intensity factor under different crack lengths is consistent with the real turbine guide vane) until the first variation pattern is consistent with the second variation pattern.

[0078] In the description of this invention, 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0079] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of multiple components or the interaction between multiple components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] In the description of this invention, it should be understood that all terms used to indicate orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as a limitation of this invention.

[0081] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0082] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications 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.

Claims

1. A method for testing the temperature gradient crack propagation of turbine guide vanes, characterized in that, Includes the following steps: Identify the critical areas of the actual turbine guide vanes; Simulation was performed on a real turbine guide vane to obtain the first variation law of stress intensity factor on the crack propagation path of the critical part; By simultaneously applying multiple independent electromagnetic induction heating modules and multiple cooling modules to the simulated structure of the turbine guide vane, the dangerous parts of the simulated structure have the same temperature gradient as the real turbine guide vane. Crack propagation tests were conducted to obtain the second variation law of stress intensity factor along the crack propagation path in the critical area; Compare the first and second variation patterns: if the first variation pattern is consistent with the second variation pattern, the crack propagation test is terminated; if the first variation pattern is inconsistent with the second variation pattern, the displacement load applied to the simulated structure is adjusted until the first variation pattern is consistent with the second variation pattern.

2. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 1, characterized in that, Identifying the critical areas of turbine guide vanes involves the following steps: Obtain the geometric model, material properties, and typical operating conditions of the turbine guide vane; Static strength analysis of turbine guide vane structure was carried out using geometric model, material property parameters and typical working conditions to obtain the magnitude and direction of the maximum principal stress of turbine guide vane. The location of the maximum principal stress on the turbine guide vane is the critical area.

3. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 2, characterized in that, The material performance parameters include the material's density, elastic modulus, Poisson's ratio, coefficient of linear expansion, and thermal conductivity.

4. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 1, characterized in that, The turbine guide vane was simulated to obtain the first variation law of stress intensity factor along the crack propagation path in the critical area, including the following steps: Construct a turbine guide vane model; Initial cracks are set at dangerous locations on the turbine guide vane model; material property parameters and crack propagation model parameters are set. Simulation calculations were performed to extract the first variation law of stress intensity factor along the crack propagation path.

5. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 1, characterized in that, By simultaneously applying multiple independent electromagnetic induction heating modules and multiple cooling modules to the simulated structure of the turbine guide vane, a temperature gradient is created in the hazardous areas of the simulated structure, including the following steps: Multiple sets of independent electromagnetic induction heating modules and multiple cooling modules are arranged on the simulation structure; The electromagnetic induction heating module and cooling module operate to obtain the real-time temperature of the dangerous parts of the simulated structure; The output power of the electromagnetic induction heating module is controlled according to the real-time temperature until the dangerous parts of the simulated structure have a temperature gradient consistent with that of the real turbine guide vanes.

6. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 5, characterized in that, The simulated structure is an I-shaped uniaxial eccentric tension member.

7. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 6, characterized in that, The geometric dimensions, shape, upper edge transition radius, and lower edge transition radius of the simulated structure are consistent with those of the turbine guide vane.

8. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 7, characterized in that, The materials of the simulated structure are selected based on preset electrical conductivity, preset magnetic permeability, preset thermal conductivity, and preset specific heat capacity.

9. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 5, characterized in that, The electromagnetic induction heating module is an electromagnetic coil.

10. The method for testing the temperature gradient crack propagation of a turbine guide vane according to claim 9, characterized in that, The electromagnetic coil is helical.

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