Turbine guide vane temperature gradient crack propagation test method

Abstract

The invention belongs to the technical field of aero-engines, and particularly relates to a turbine guide vane temperature gradient crack propagation test method which comprises the following steps: determining a dangerous part of a real turbine guide vane; carrying out analogue simulation on the real turbine guide vane to obtain a first change rule of a stress intensity factor on a crack propagation path of the dangerous part; a plurality of groups of independent electromagnetic induction heating modules and a plurality of cooling modules act on a simulation structure of the turbine guide vane at the same time, so that a dangerous part of the simulation structure has a temperature gradient consistent with that of a real turbine guide vane; carrying out a crack propagation test to obtain a second change rule of a stress intensity factor on a crack propagation path of the dangerous part; comparing the first change rule with 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 the displacement load applied to the simulation structure. According to the invention, the accuracy of the obtained test data is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aero-engines, and in particular relates to a method for testing temperature gradient crack growth in turbine guide vanes. Background Art

[0002] Aircraft engine turbine guide vanes (such as turbine blades and combustion chamber panels) are subjected to extremely harsh operating conditions for extended periods of time during service. These components are often subjected to a combination of high temperatures, high stresses, and significant thermal gradients. These complex operating conditions not only exacerbate material degradation mechanisms such as high-temperature creep, fatigue damage, and oxidative corrosion, but also significantly impact crack initiation and propagation behavior. Therefore, it is necessary to conduct crack growth tests on turbine guide vanes.

[0003] During service, turbine guide vanes are subjected to a non-uniform temperature gradient heating environment. However, existing crack growth test equipment often utilizes uniform heating (such as integral furnace heating or radiation heating) and uniaxial loading, which cannot accurately reproduce the non-uniform, multi-physics coupling environment experienced by turbine guide vanes in actual service. This simplified loading and heating method significantly limits the representativeness of the test data and its engineering reference value.

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

[0005] In order to improve the accuracy of test data obtained from crack loading tests, thereby increasing the representativeness and engineering reference value of the test data, the present invention provides a turbine guide vane temperature gradient crack growth test method.

[0006] The present invention includes the following technical solutions:

[0007] The present invention provides a turbine guide vane temperature gradient crack growth test method, comprising the following steps:

[0008] Identify the dangerous locations of real turbine guide vanes;

[0009] By simulating real turbine guide vanes, we can obtain the first variation law of the stress intensity factor along the crack propagation path in dangerous areas.

[0010] By using multiple independent electromagnetic induction heating modules and cooling modules to simultaneously act on the simulated structure of the turbine guide vanes, the temperature gradient at the dangerous parts of the simulated structure is consistent with that of the real turbine guide vanes.

[0011] Conduct crack growth tests to obtain the second variation law of the stress intensity factor along the crack growth path in dangerous areas;

[0012] Compare the first change law and the second change law: if the first change law is consistent with the second change law, end the crack propagation test; if the first change law is inconsistent with the second change law, adjust the displacement load applied to the simulated structure until the first change law is consistent with the second change law.

[0013] Furthermore, determining the dangerous position of the turbine guide vane includes the following steps:

[0014] Obtain the geometric model, material performance parameters and typical operating conditions of turbine guide vanes;

[0015] Use geometric models, material performance parameters, and typical operating conditions to conduct static strength analysis of turbine guide vane structures and obtain the magnitude and direction of the maximum principal stress in the turbine guide vanes;

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

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

[0018] Furthermore, a simulation is performed on the turbine guide vane to obtain a first variation law of the stress intensity factor on the crack propagation path of the dangerous part, including the following steps:

[0019] Use crack growth analysis software to build a turbine guide vane model;

[0020] Set initial cracks at dangerous locations on the turbine guide vane model; set material performance parameters and crack propagation model parameters;

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

[0022] Furthermore, the steps of simultaneously applying multiple independent electromagnetic induction heating modules and multiple cooling modules to the simulated structure of the turbine guide vanes to provide a temperature gradient at the dangerous parts of the simulated structure include the following:

[0023] Arranging multiple groups of independent electromagnetic induction heating modules and multiple cooling modules on the simulation structure;

[0024] The electromagnetic induction heating module and the cooling module work 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 part of the simulated structure has a temperature gradient consistent with that of the real turbine guide vane.

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

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

[0028] Furthermore, the material of the simulation structure is selected according to a preset electrical conductivity, a preset magnetic permeability, a preset thermal conductivity and a preset specific heat capacity.

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

[0030] Furthermore, the electromagnetic coil is spiral-shaped.

[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 test data obtained from crack loading tests, and has the advantages of improving the representativeness of the test data and the engineering reference value.

[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, breaking through the limitations of a uniform temperature field. It can accurately simulate the crack propagation behavior of the hot end components of an aircraft engine under extreme temperature gradients, and provide a reliable experimental means for the damage tolerance assessment of high-temperature materials.

[0034] 3. The present invention simulates the real structure of the turbine guide vane through crack propagation analysis software, calculates the critical crack size, extracts the variation law of the stress intensity factor on the crack propagation path, designs an I-shaped uniaxial eccentric stretching simulation structure, and retains the key geometric dimensions.

[0035] 4. This invention uses variable-amplitude loading (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 simulated structure's stress intensity factor consistent with the real structure. This solves the problem of traditional uniaxial tensile loading simulators incompletely simulating the variation of the real structure's stress intensity factor with crack length.

[0036] 5. The present invention forms a controllable high temperature gradient field on the surface of the simulated structure by combining electromagnetic induction heating and ventilation cooling, accurately simulating the actual working conditions of the turbine guide vanes of an aircraft engine.

[0037] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings.

[0039] Figure 1 The flow chart of a turbine guide vane temperature gradient crack growth test method according to an embodiment of the present invention is as follows: Figure 1 ;

[0040] Figure 2 The flow chart of a turbine guide vane temperature gradient crack growth test method according to an embodiment of the present invention is as follows: Figure 2 . DETAILED DESCRIPTION

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] The following description provides many different embodiments or examples for implementing different features of the present invention. The components and arrangements described in the following specific examples are only used to simplify the present invention and are only used as examples, not to limit the present invention.

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0044] This embodiment provides a method for testing the temperature gradient crack growth of turbine guide vanes. Figure 1 As shown, the following steps are included:

[0045] Identify the dangerous locations of real turbine guide vanes;

[0046] By simulating real turbine guide vanes, we can obtain the first variation law of the stress intensity factor along the crack propagation path in dangerous areas.

[0047] By using multiple independent electromagnetic induction heating modules and cooling modules to simultaneously act on the simulated structure of the turbine guide vanes, the temperature gradient at the dangerous parts of the simulated structure is consistent with that of the real turbine guide vanes.

[0048] Conduct crack growth tests to obtain the second variation law of the stress intensity factor along the crack growth path in dangerous areas;

[0049] Compare the first change law and the second change law: if the first change law is consistent with the second change law, end the crack propagation test; if the first change law is inconsistent with the second change law, adjust the displacement load applied to the simulated structure until the first change law is consistent with the second change law.

[0050] The geometric model, material performance parameters and typical operating conditions of the turbine guide vane are obtained. Through thermal-solid coupled load analysis, the location with the maximum first principal stress is determined to be the dangerous location, and the initial crack plane is selected.

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

[0052] Obtain the geometric model, material performance parameters and typical operating conditions of turbine guide vanes;

[0053] Conduct static strength analysis of turbine guide vane structures using geometric models, material performance parameters, and typical operating conditions. This involves analyzing the thermal-solid coupling load characteristics of turbine guide vanes under typical operating conditions to determine the magnitude and direction of the maximum principal stress in the turbine guide vanes.

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

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

[0056] In some embodiments, simulating a turbine guide vane to obtain a first variation law of a stress intensity factor on a crack propagation path at a dangerous location includes the following steps:

[0057] Use crack growth analysis software to build a turbine guide vane model;

[0058] Set initial cracks at dangerous locations on the turbine guide vane model; set material performance parameters and crack propagation model parameters;

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

[0060] In some embodiments, the steps of simultaneously applying a plurality of independent electromagnetic induction heating modules and a plurality of cooling modules to a simulated structure of a turbine guide vane to provide a temperature gradient at a dangerous portion of the simulated structure include the following:

[0061] Arranging multiple groups of independent electromagnetic induction heating modules and multiple cooling modules on the simulation structure;

[0062] The electromagnetic induction heating module and the cooling module work 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 part of the simulated structure has a temperature gradient consistent with that of the real turbine guide vane.

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

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

[0066] In some embodiments, the material of the simulation structure is selected based on a preset electrical conductivity, a preset magnetic permeability, a preset thermal conductivity, and a 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 the embodiment of the present invention, exemplary:

[0070] like Figure 2 As shown in the figure, the geometric model, material performance parameters and typical operating conditions of the real turbine guide vane are obtained. According to the thermal-solid coupling load characteristics in the typical operating conditions of the turbine guide vane, the real structural static strength analysis of the turbine guide vane is carried out to obtain the magnitude and direction of the maximum principal stress of the structure, determine the maximum principal stress position as the dangerous position, obtain the stress gradient of the dangerous position and select the plane perpendicular to the maximum principal stress as the initial crack plane.

[0071] The turbine guide vane is simulated using crack growth analysis software. An initial crack is assumed in the dangerous part, the required material parameters and crack growth model parameters are set, and the critical crack size of the dangerous part is calculated. The critical crack size represents the size of the crack in the depth direction. The stress intensity factor variation law on the crack growth path (i.e., the second variation law) is extracted, and the geometric dimensions that have a major impact on the stress intensity factor on the crack growth path are determined. In order to ensure that the key geometric dimensions remain unchanged and better simulate the actual load conditions of the turbine guide vane tension-bending coupling, the simulation structure is designed as an I-shaped uniaxial eccentric tensile part, and the support 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 upper edge plate transition angle radius, and the lower edge plate transition angle radius. The crack growth model selected is the Paris formula:

[0072]

[0073] Where C is the material constant, a is the crack length, N is the number of cycles, da is the differential of the crack length, and dN is the differential of the number of cycles. It represents the extension of the crack length a after each load cycle, and ΔK is the difference between the maximum and minimum stress intensity factors defined in the stress intensity factor range (ΔK=K max -K min ), C reflects the material's ability to resist fatigue crack growth, and n represents the sensitivity of the crack growth rate to the range of stress intensity factors.

[0074] Considering that turbine guide vanes are subject to large mechanical loads and high temperature gradients at the same time, under high temperature gradients, due to the mismatch in thermal expansion coefficients caused by temperature differences in different regions of the material, high stress concentration is generated inside, which may lead to the initiation and propagation of cracks. In this paper, electromagnetic-thermal-solid coupling simulation is performed using simulation software to obtain the real temperature gradient of the turbine guide vanes.

[0075] Using multiple independent electromagnetic induction heating modules, selecting the appropriate electromagnetic coil shape, setting the required material properties, setting the heat transfer boundary conditions, determining the parameters of the ventilation cooling module, covering the non-heating parts of the simulated structure, adjusting the flow rate and direction of the cooling air in the cooling module, as well as the coverage area of ​​the cooling air, to ensure that the temperature gradient of the simulated structure in a crack-free state is consistent with the actual temperature gradient.

[0076] By setting the loading mode to displacement loading, a load is applied to the simulated structure to carry out a crack propagation test, and the change law of the stress intensity factor on the crack propagation path of the dangerous part (i.e., the second change law) is obtained.

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

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

[0079] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical, electrical, or intercommunication connections; direct or indirect connections through an intermediary; and may encompass internal connectivity between multiple components or interactions between multiple components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0080] In the description of the present invention, it should be understood that all terms used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and cannot be understood as a limitation on the present invention.

[0081] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may also include the first and second features not being in direct contact but being in contact via another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or diagonally above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or diagonally below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0082] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements 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 turbine guide vane temperature gradient crack growth test method, characterized in that: The steps include: Identify the dangerous locations of real turbine guide vanes; By simulating real turbine guide vanes, we can obtain the first variation law of the stress intensity factor along the crack propagation path in dangerous areas. By using multiple independent electromagnetic induction heating modules and cooling modules to simultaneously act on the simulated structure of the turbine guide vanes, the temperature gradient at the dangerous parts of the simulated structure is consistent with that of the real turbine guide vanes. Conduct crack growth tests to obtain the second variation law of the stress intensity factor along the crack growth path in dangerous areas; Compare the first change law and the second change law: if the first change law is consistent with the second change law, end the crack propagation test; if the first change law is inconsistent with the second change law, adjust the displacement load applied to the simulated structure until the first change law is consistent with the second change law.

2. A turbine guide vane temperature gradient crack growth test method according to claim 1, characterized in that: Determining the hazardous areas of turbine guide vanes involves the following steps: Obtain the geometric model, material performance parameters and typical operating conditions of turbine guide vanes; Use geometric models, material performance parameters, and typical operating conditions to conduct static strength analysis of turbine guide vane structures and obtain the magnitude and direction of the maximum principal stress in the turbine guide vanes; The location of the maximum principal stress on the turbine guide vane is the dangerous location.

3. A turbine guide vane temperature gradient crack growth test method according to claim 2, characterized in that: The material performance parameters include material density, elastic modulus, Poisson's ratio, linear expansion coefficient and thermal conductivity.

4. A turbine guide vane temperature gradient crack growth test method according to claim 1, characterized in that: The turbine guide vane simulation is performed to obtain the first variation law of the stress intensity factor along the crack propagation path in the dangerous area, including the following steps: Construct a turbine guide vane model; Set initial cracks at dangerous locations on the turbine guide vane model; set material performance parameters and crack propagation model parameters; Simulation calculations were performed to extract the first variation law of the stress intensity factor on the crack propagation path.

5. A turbine guide vane temperature gradient crack growth test method according to claim 1, characterized in that: The following steps are involved in applying a temperature gradient to the dangerous parts of the simulated structure by simultaneously applying multiple independent electromagnetic induction heating modules and multiple cooling modules to the simulated structure of the turbine guide vanes: Arranging multiple groups of independent electromagnetic induction heating modules and multiple cooling modules on the simulation structure; The electromagnetic induction heating module and the cooling module work 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 part of the simulated structure has a temperature gradient consistent with that of the real turbine guide vane.

6. A turbine guide vane temperature gradient crack growth test method according to claim 5, characterized in that: The simulated structure is an I-shaped uniaxial eccentric tensile member.

7. A turbine guide vane temperature gradient crack growth test method according to claim 6, characterized in that: The geometric dimensions, geometric shape, upper edge plate transition angle radius, and lower edge plate transition angle radius of the turbine guide vane edge plate in the simulation structure are consistent with those of the turbine guide vane.

8. A turbine guide vane temperature gradient crack growth test method according to claim 7, characterized in that: The material of the simulation structure is selected according to a preset electrical conductivity, a preset magnetic permeability, a preset thermal conductivity and a preset specific heat capacity.

9. A turbine guide vane temperature gradient crack growth test method according to claim 5, characterized in that: The electromagnetic induction heating module is an electromagnetic coil.

10. A turbine guide vane temperature gradient crack growth test method according to claim 9, characterized in that: The electromagnetic coil is spiral-shaped.

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