A method for evaluating the life and remaining life damage of turbine blades under service environment

Abstract

This application belongs to the field of life measurement of aero-engine turbine blades. A method for evaluating the life and remaining life damage of turbine blades under service conditions includes conducting a test run of the aero-engine turbine blades under actual service conditions and statistical analysis of service loads, and correcting the calculation state; measuring the service blade temperature of the aero-engine turbine blades; correcting the known temperature calculation model to obtain a corrected temperature calculation model; correcting the known input load, and based on the corrected input load, conducting a sampling simulation test of real turbine blades on non-service blades to obtain the mechanical properties of non-service blades under the actual service conditions of real components; and correcting the material model. Based on the corrected calculation state, corrected input load, and corrected material model, a life damage evaluation model of aero-engine turbine blades under service conditions is obtained, providing a systematic and accurate method for evaluating the life damage of turbine blades under service conditions.

Description

Technical Field

[0001] This application belongs to the field of life measurement of aero-engine turbine blades, and particularly relates to a method for evaluating the life and remaining life damage of turbine blades under service conditions. Background Art

[0002] The present invention relates to the field of aero-engine strength design, and particularly relates to the application of turbine blade strength and life design, and can also be used as a reference for the strength and life design of other components.

[0003] Turbine blades are one of the most critical components of aero-engines. Due to the extremely harsh working environment of turbine blades, the loads they bear are very complex, and the blade structure has a complex geometric shape and inner cavity. During operation, it is in a very complex stress state, resulting in complex damage modes and many influencing factors, and it is difficult to conduct experimental verification at the same time. The life damage evaluation of turbine blades itself is a relatively complex systematic project, involving multiple disciplines such as strength, structure, aerodynamics, heat transfer, materials, testing, and failure analysis. Among them, the life analysis process involves materials, loads, method models, etc. The more prominent key technical problems include the acquisition of the true service loads (temperatures) of turbine blades, and the differences between real components and standard components are not yet mastered, resulting in low accuracy of turbine life analysis; the experimental verification process involves component-level, simulation-component-level, component-level (very difficult), and engine-level tests. Through multi-level tests combined with metallographic analysis technology, blade damage evaluation can be carried out, but it is very difficult to evaluate real damage based on component-level tests. At the same time, combined with the problems in engineering design and use, it can be seen that only a single specialty can no longer meet the requirements of life damage evaluation of aero-engine turbine blades under service conditions. Therefore, there is an urgent need to establish a multi-specialty collaborative life damage evaluation method for aero-engine turbine blades applicable to engineering.

[0004] In terms of the disclosed prior art, domestic research institutes and schools mainly conduct research on the above-mentioned various professional technical difficulties, and have not yet formed a multi-specialty collaborative life damage evaluation method and system.

[0005] 1) For the life design stage of aero-engine turbine blades, due to the comprehensive influence of factors such as loads, materials, and life models, the accuracy of life analysis results is relatively low, and there is a large deviation from the results of engine full-load tests and field use, and the technical support for engine life determination needs to be improved;

[0006] 2) For the experimental verification stage of aero-engine turbine blades, it is difficult to conduct life experimental verification of turbine blades under service conditions. It mainly relies on engine-level tests, and there is a lack of effective simulation-component-level and real-component-level experimental verification methods;

[0007] 3) In the prior art, more attention is paid to the development of professional technical capabilities, and the collaborative integration of multiple specialties is not concerned. It can neither meet the requirements for life damage assessment of aero-engine turbine blades under service conditions nor facilitate the comprehensiveness of the improvement of technical capabilities of related specialties and engineering transformation. Summary of the Invention

[0008] To solve the above problems, the present application provides a method for life damage assessment of turbine blades under service conditions, including:

[0009] Step S1: Conduct a test run of the aero-engine turbine blade under the actual service condition and statistical analysis of the service load, correct the known calculation state, and obtain the corrected calculation state;

[0010] Step S2: Measure the service blade temperature of the aero-engine turbine blade under the engine service condition;

[0011] Step S4: Correct the known temperature calculation model based on the service blade temperature to obtain the corrected temperature calculation model;

[0012] Step S5: Correct the known input load based on the corrected calculation state and the corrected temperature calculation model to obtain the corrected input load;

[0013] Step S6: Conduct a real turbine blade sampling simulation test on the unserviced blade based on the corrected input load to obtain the mechanical properties of the unserviced blade under the actual service conditions of the real component; and correct the material model known in the database to obtain the corrected material model;

[0014] Step S7: Obtain a life damage assessment model of the aero-engine turbine blade under the service environment based on the corrected calculation state, the corrected input load, and the corrected material model.

[0015] Preferably, the actual service condition test run and service load statistical analysis in Step S1 include: identifying the large state time and obtaining the cross-section temperature, aerodynamic load, and rotational speed load parameters of the engine related to the large state time.

[0016] Preferably, based on the large state time, the cross-section temperature, aerodynamic load, and rotational speed load parameters of the engine related to the large state time, and in combination with the strength points and life points for aero-engine design, the known calculation state is corrected, where the large state time is the process time from when the engine enters a preset state to when it enters another preset state.

[0017] Preferably, after measuring the temperature of the in-service blade in step S2, the temperature of the in-service blade is further interpreted. Interpreting the temperature of the in-service blade includes: detecting the in-service blade through a metallographic structure detection technique, interpreting the actual in-service temperature of the in-service blade based on the results of the metallographic structure detection, and verifying the interpretation result of the actual in-service temperature of the in-service blade with the temperature of the in-service blade.

[0018] Preferably, the temperature of the in-service blade is further corrected for the recalculated state.

[0019] Preferably, the corrected input load includes: the corrected temperature load and the corrected aerodynamic load.

[0020] Preferably, after obtaining the life damage evaluation model of the aero-engine turbine blade under the service environment, the strength and life results of multiple turbine blades are calculated through the evaluation model, and the results are compared with the strength and life results of multiple turbine blades under the bench test and service test, and the life damage evaluation model of the aero-engine turbine blade under the service environment that meets the preset requirements is obtained through multiple iterations.

[0021] A method for evaluating the remaining life damage of a turbine blade under a service environment includes:

[0022] Sampling the blade after service to obtain a test piece after service;

[0023] Carrying out a sampling simulation test of a real turbine blade on the test piece, and performing metallographic structure analysis on the test piece before and after the test;

[0024] Combining the test results and the metallographic structure analysis results to obtain the service damage and the used service life of the blade after service under the actual service conditions;

[0025] Calculating the total life of the blade after service through the above-mentioned method for evaluating the life damage of the turbine blade under the service environment, and obtaining the remaining life of the blade after service through the total life, the service damage and the used service life.

[0026] The advantages of this application include:

[0027] 1) A multi-disciplinary collaborative life damage evaluation method for aero-engine turbine blades under the service environment is proposed, improving the accuracy of life analysis of aero-engine turbine blades;

[0028] 2) An engineering applicable test verification method for aero-engine turbine blades is proposed to realize the evaluation of service damage and remaining life of turbine blades;

[0029] 3) Propose ideas for improving multi - professional technical capabilities related to aero - engine turbine blades, such as strength, structure, aerodynamics, heat transfer, materials, testing, failure analysis, etc., and a technical development system, which is beneficial to the comprehensive development of professional technical capabilities and the improvement of multi - professional collaborative design capabilities. Brief Description of the Drawings

[0030] Figure 1 It is a flowchart of the life - damage evaluation method for turbine blades under the service environment in a preferred embodiment of this application. Detailed Embodiment

[0031] To make the purpose, technical solutions, and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings in the embodiments of this application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of this application. The embodiments described below with reference to the drawings are exemplary and are intended to explain this application and should not be construed as limiting this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the drawings.

[0032] As Figure 1 shown, the method provided by this application includes:

[0033] Step 1: Input

[0034] For the convenience of description and calculation, this step is to uniformly obtain the known parameters in the calculation steps and clarify all the known data used for the life - damage evaluation of aero - engine turbine blades under the service environment, which includes: calculation state, service state, blade model, real blade, material property data, service load, aerodynamic data, temperature data; where the calculation state is the theoretical state of aero - engine design; and the service load, aerodynamic data, and temperature data have different parameters under different engine states.

[0035] Step 2: Service Load Analysis

[0036] According to the various parameters and states in Step 1, conduct real - service - state test runs and statistical analysis of service loads, and identify the large - state time and the cross - section temperature, aerodynamic load, and rotational - speed load parameters related to the engine;

[0037] Among them, the large - state time is the process time for the aero - engine to enter from one preset state to another preset state; the cross - section temperature is the ambient temperature of the specified cross - section of the engine.

[0038] Step 3: Calculation State Correction

[0039] Based on the large state time obtained in step 2 and its engine-related cross-sectional temperature, aerodynamic load, and rotational speed load parameters, and in combination with the strength points and life points for aeroengine design, the calculation state is corrected to determine a set of corrected calculation states covering the life under actual service conditions;

[0040] Step 4, Service environment measurement

[0041] Based on the conditions of the corrected calculation state obtained in step 3, data analysis of the actual working temperature of the engine turbine blades is carried out, that is, the actual working temperature of the engine turbine blades is measured. While improving the corrected calculation state, the actually measured service blade temperature is matched with the statistical load of the corresponding corrected calculation state;

[0042] Step 5, Service blade temperature interpretation

[0043] The turbine blades after service are detected by metallographic structure detection technology. The actual service temperature of the turbine blades is interpreted through the detection results, which are mutually verified with the service blade temperature obtained in step 4 and then matched again with the statistical load in the corrected calculation state described in step 3.

[0044] Step 6, Temperature model correction result

[0045] Based on steps 2, 3, 4, and 5, the known temperature calculation model in the database is corrected to obtain a corrected temperature calculation model, improving the calculation accuracy of temperature load;

[0046] Step 7, Input load calculation

[0047] Based on the corrected calculation state in step 3 and applying the corrected blade temperature model in step 6, load calculation under the actual service conditions of the engine is carried out;

[0048] Step 8, Input load correction result

[0049] Based on the load calculation in step 7, the known input load in the database is corrected to obtain the corrected input load required for the life assessment of the engine under actual service conditions, which includes the corrected temperature load and the corrected aerodynamic load.

[0050] Step 9, Material data supplement

[0051] Based on step 8, according to the corrected temperature load, the accelerated test method is applied to quickly obtain material property data within the service temperature range;

[0052] Step 10, Sampling of unserviced blades

[0053] Based on the turbine blade model in Step 1, formulate a sampling plan for unserviced blades and a design plan for simulation test pieces to obtain the true mechanical properties of different parts of the turbine blade;

[0054] Step 11. Sampling simulation test

[0055] Based on the sampling plan in Step 10 and the corrected temperature load in Step 8, conduct a sampling simulation test of the true turbine blade to obtain the mechanical properties of the true component under actual service conditions;

[0056] Step 12. Results of material model correction

[0057] Based on the test results in Steps 9 and 11, correct the material model known in the database to obtain the corrected material model, further improve the accuracy of the material model, and further improve the accuracy of turbine blade life calculation;

[0058] Step 13. Strength and life analysis

[0059] Based on the corrected calculation state in Step 3, the corrected input load in Step 8, and the corrected material model in Step 12, conduct strength and life analysis of the turbine blade in the true service environment;

[0060] Step 14. Results of calculated life correction

[0061] Compare the strength and life analysis results obtained from the calculation in Step 13 with the strength and life analysis results during engine test runs and service, evaluate whether the calculation results meet the engine life design requirements, and obtain through multiple iterations a life damage evaluation model for the aeroengine turbine blade under the service environment that meets the preset requirements.

[0062] Step 15. Formulation of simulation test plan

[0063] Based on Step 14 and combined with the input data in Step 1, formulate a simulation test plan for the turbine blade, including sampling tests of serviced blades and metallographic structure detection.

[0064] Step 16. Sampling of serviced blades

[0065] Based on the test plan formulated in Step 15, process and obtain sampling simulation test pieces of the blades after service;

[0066] Step 17. Sampling simulation test

[0067] Based on the test pieces obtained in Step 16, conduct a sampling simulation test of the true turbine blade according to the test plan in Step 15;

[0068] Step 18. Metallographic structure analysis

[0069] Conduct metallographic structure analysis before and after sampling according to the test plan in Step 15;

[0070] Step 19, Simulation test life results

[0071] Combining the test results of Step 17 and Step 18 and the metallographic structure analysis results, obtain the service damage and the already used service life under the actual service conditions of typical parts of the real component;

[0072] Step 20, Life damage evaluation

[0073] Combining the life calculation results of Step 14 and the service damage and the already used service life under the actual service conditions of typical parts in Step 19, conduct the evaluation of service damage and remaining life of other concerned parts of the turbine blade.

[0074] As mentioned above, it is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by this application should be covered within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims described.

Claims

1. A method for evaluating the life damage of a turbine blade under its service environment, characterized in that, Including: Step S1: Conduct a test run and statistical analysis of service loads on the turbine blades of an aero-engine under actual service conditions, correct the known calculation conditions, and obtain the corrected calculation conditions; Step S2: Measure the service blade temperature of the aero-engine turbine blade under the engine's service conditions; Step S3: Correct the known temperature calculation model based on the service blade temperature to obtain the corrected temperature calculation model; Step S4: Correct the known input loads based on the corrected calculation conditions and the corrected temperature calculation model to obtain the corrected input loads; Step S5: Based on the corrected input loads, conduct a real turbine blade sampling simulation test on the unserviced blades to obtain the mechanical properties of the unserviced blades under the actual service conditions of the real components; and correct the material models known in the database to obtain the corrected material models; Step S6: Based on the corrected calculation conditions, the corrected input loads, and the corrected material models, obtain the life damage evaluation model for the aero-engine turbine blade under the service environment. The real service condition test run and service load statistical analysis described in Step S1 include: identifying the large state time and obtaining the cross-sectional temperature, aerodynamic load, and rotational speed load parameters of the engine related to the large state time. The large state time is the process time from when the engine enters one preset state to when it enters another preset state. Based on the large state time, the cross-sectional temperature, aerodynamic load, and rotational speed load parameters of the engine related to the large state time, and in combination with the strength points and life points used in the aero-engine design, correct the known calculation conditions.

2. The method for evaluating the life damage of a turbine blade under its service environment according to claim 1, characterized in that, After measuring the service blade temperature in Step S2, there is also an interpretation of the service blade temperature. The interpretation of the service blade temperature includes: detecting the service blade through metallographic structure detection technology, interpreting the actual service temperature of the service blade based on the results of the metallographic structure detection, and verifying the interpretation result of the actual service temperature of the service blade with the service blade temperature.

3. The method for evaluating the life damage of a turbine blade under its service environment according to claim 1, characterized in that, The service blade temperature corrects the corrected calculation conditions again.

4. The method for evaluating the life damage of a turbine blade under its service environment according to claim 1, characterized in that, The corrected input loads include: the corrected temperature load and the corrected aerodynamic load.

5. The method for evaluating the life damage of a turbine blade under its service environment according to claim 1, characterized in that, After obtaining the life damage evaluation model for the aero-engine turbine blade under the service environment, calculate the strength and life results of multiple turbine blades through the evaluation model, compare the results with the strength and life results of multiple turbine blades in the test run and service tests, and iteratively obtain the life damage evaluation model for the aero-engine turbine blade under the service environment that meets the preset requirements.

6. A method for evaluating the remaining life damage of a turbine blade under its service environment, characterized in that, Including: Sampling the blades after service to obtain test pieces after service; Conducting a real turbine blade sampling simulation test on the test pieces and performing metallographic structure analysis on the test pieces before and after the test; Combining the test results and the metallographic structure analysis results to obtain the service damage and the used service life of the blades after service under the actual service conditions; Calculate the total life of the blades after service through the life damage evaluation method for the aero-engine turbine blade under the service environment of any one of claims 1-5, and obtain the remaining life of the blades after service through the total life, the service damage, and the used service life.

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