Durability test method of turbocharger turbine

Abstract

The invention relates to the technical field of turbine blade test methods, and particularly discloses a turbocharger turbine durability test method, which comprises the following steps: acquiring a target position area according to a distribution cloud chart of a pressure field and a speed field of a historical turbine blade; fatigue testing is conducted on the target position area in different cyclic load working condition modes, and the turbine blade state of the corresponding mode is obtained; determining the blade temperature and the supercharger rotating speed during turbine resonance failure, the blade temperature and the supercharger rotating speed during turbine blade strain, the blade temperature and the supercharger rotating speed during turbine blade damage, and the blade temperature and the supercharger rotating speed during turbine blade breakage based on a fatigue test to determine limit values of different turbine blade states; and coupling different turbine blade states and limiting values thereof to calculate the total fatigue life time of the turbine blade, inputting the total life time into the life prediction model, outputting a safety coefficient, and verifying the safety coefficient so as to improve the durability test of the turbine blade in the cyclic load working condition mode.

Description

Technical Field

[0001] The present invention relates to the technical field of turbine blade testing methods, and in particular to a durability testing method for a turbocharger turbine. Background Art

[0002] Turbochargers are commonly used in the operation of automobile engines. Turbochargers need to operate at high speeds and high temperatures. They are also equipped in the power systems of various vehicles. The durability of the turbine is reflected in whether it meets the requirements of structural performance and material durability throughout its life cycle. Patent publication number CN116878903A discloses a 60-hour endurance test method for an aviation gas turbine shaft engine. The method states that "the engine is subjected to several test stages, with the engine's operating state switching during each stage. The engine's operating states include idling, maximum continuous, takeoff, continuous emergency, maximum transient, and increasing speed. This method can fully verify the structural integrity and durability of the engine, ensuring flight safety after installation." However, although the above content fully considers the structural performance integrity and durability of the turboshaft engine in the flight working state, it does not consider the impact of the turbine's thermal mechanical fatigue and blade vibration coupling load on durability; and due to the lack of a monitoring process for turbine fatigue conditions during the test, it is impossible to ensure the safety monitoring of the drivers in the durability test and to formulate standards for fatigue failure judgment criticality; in actual application, the lack of safety monitoring and turbine blade fatigue prediction may cause safety risks for drivers and operators. Summary of the Invention

[0003] The purpose of the present invention is to provide a durability test method for a turbocharger turbine to solve the following technical problems: How to improve the durability testing method of turbine blades under cyclic load conditions and obtain fatigue failure judgment criteria.

[0004] The purpose of the present invention can be achieved through the following technical solutions: Durability test method for turbocharger turbine, the method includes: Step 1: Obtain the target location area based on the distribution cloud map of the pressure field and velocity field of the historical turbine blade; Step 2: Perform fatigue testing on the target location area under different cyclic load conditions to obtain the turbine blade status of the corresponding mode, where the turbine blade status includes turbine resonance failure, turbine blade strain, turbine blade damage, and turbine blade fracture; Step 3: Based on fatigue testing, determine the blade temperature and supercharger speed at turbine resonance failure, the blade temperature and supercharger speed at turbine blade strain, the blade temperature and supercharger speed at turbine blade damage, and the blade temperature and supercharger speed at turbine blade fracture to determine limit values ​​for different turbine blade states; Step 4: Couple different turbine blade states and their limit values ​​to calculate the total life time of turbine blade fatigue, input the total life time into the life prediction model, output the safety factor and verify it.

[0005] Preferably, there are three modes of cyclic load conditions, including: centrifugal force cyclic mode, temperature load coupled cyclic mode, and centrifugal force and temperature load coupled combined cyclic mode.

[0006] Preferably, step three includes: S1. Obtain the target position area of ​​the turbine blade: The turbine blades are divided into several unit cells using the grid method; Digitally measure the temperature of several unit cells in the turbine blade, set several temperature ranges from small to large, and use RGB equivalent color temperature to represent different temperature ranges; Select the cell corresponding to the highest equivalent color temperature RGB within the temperature range as the target location area, and count the total number of cells in the target location area ; S2. Statistical target location area The temperature set within a cell ; Calculate the average value of the temperature set ; S3. Obtain the temperature of the turbine blades in the current cyclic load mode ; and obtain the supercharger speed as a limiting value.

[0007] Preferably, the method for obtaining the total life time of turbine blade fatigue by coupling different turbine blade states in step 4 is: Obtaining different cyclic load conditions to record state parameters corresponding to different turbine blade states and the number of cycles when damage occurs to different turbine blade states; the state parameters corresponding to different turbine blade states include: recording the resonance frequency of turbine resonance failure, recording the strain amplitude of turbine blade strain, recording the crack length of turbine blade damage, and recording the corresponding strength of turbine blade fracture; Obtaining different cyclic load conditions to record state parameters corresponding to different turbine blade states and the number of cycles recorded when damage corresponding to different turbine blade states is recorded; The state parameters corresponding to different turbine blade states include: the resonance frequency for recording turbine resonance failure, the strain amplitude for recording turbine blade strain, the crack length for recording turbine blade damage, and the position strength for recording turbine blade fracture; The crack length of the turbine blade and the position strength of the turbine blade fracture are obtained according to the centrifugal force cycle mode; the strain amplitude of the turbine blade strain is obtained according to the temperature load coupling cycle mode; and the resonance frequency of the turbine resonance failure is obtained according to the centrifugal force and temperature load coupling composite cycle mode.

[0008] Preferably, the total number of times the limit value is exceeded is recorded until the corresponding turbine blade state is reached. , obtain the multi-mode damage coupling model for cyclic loading cases:

[0009] in, is the total damage value of the blade, which is composed of the coupling of low-cycle / high-cycle fatigue damage, creep damage and crack extension damage; Low-cycle / high-cycle fatigue damage: The first stress of the turbine blade under the current cyclic load mode The cumulative number of cycles exceeding the limit value; and ∈ ; The number of cycles recorded when the turbine blade reaches the damage corresponding to the turbine blade state under the stress of the current cyclic load condition mode; Creep damage: For the The creep strain rate exceeds the limit value for the second time; is the number of creep life cycles, which is related to the current creep strain rate and temperature Related; Crack propagation damage: is the crack length; is the crack growth life times, which is related to the current crack length and temperature Related; is the time interval from the initial length to the critical length of the crack; By formula Calculate the total lifespan , To complete a cycle time.

[0010] Preferably, the calculation process for obtaining the safety factor based on the life prediction model is: By formula Calculate the safety factor ; is the total life expectancy prediction; Enter a value for Total Life; is the dispersion coefficient, ranging from 1.5 to 2.0; is the environmental correction factor, which is 0.8-0.9 in high temperature oxidation environment.

[0011] Preferably, the method for verifying the safety factor is: Apply equivalent loads (such as centrifugal force + thermal load combined loading) on ​​a rotating test bench to monitor crack initiation and propagation; Eddy current testing (ECT) and infrared thermal imaging are used to verify the predicted crack location (error < 2mm); Correct the lifespan prediction model: Introduce machine learning (such as XGBoost) to correct the prediction error online.

[0012] Preferably, the life prediction model is corrected by:

[0013] in, is the fatigue life prediction value, unit: number of cycles; is the model baseline fatigue life, unit: number of cycles; is the temperature sensitivity coefficient; is the temperature change; is the reference temperature.

[0014] Beneficial effects of the present invention: (1) The present invention obtains the turbine blade status of the corresponding mode through fatigue testing of different cyclic load working conditions. The change of the turbine blade status is mainly due to the obvious failure change of the turbine blade. The fatigue modes for effectively identifying failure changes include turbine resonance failure, turbine blade strain, turbine blade damage, and turbine blade fracture. These four turbine blade status conditions reflect the fatigue failure of the turbine blade and help to quickly realize the judgment of the durability of the blade.

[0015] (2) The present invention is based on four types of situations in which the state of the turbine blade changes, and obtains the main reference values ​​for reaching the four types of turbine blade states, namely, obtaining the blade temperature and the supercharger speed when the turbine resonance fails, obtaining the blade temperature and the supercharger speed when the turbine blade is strained, obtaining the blade temperature and the supercharger speed when the turbine blade is damaged, and obtaining the blade temperature and the supercharger speed when the turbine blade is broken, so as to achieve accurate acquisition of the reference value information of the change of the target position of the turbine blade.

[0016] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 FIG1 is a step diagram of a durability test method for a turbocharger turbine according to the present invention; Figure 2 Schematic diagram of the target position area of ​​the turbine blade of the present invention; Figure 3 This is a schematic diagram of the grid distribution of turbine blades according to the present invention; Figure 4 This is a flow chart of the durability test method for a turbocharger turbine according to the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] See also Figure 1-4 As shown, the present invention is a durability test method for a turbocharger turbine, the method comprising: Step 1: Obtain the target location area based on the distribution cloud map of the pressure field and velocity field of the historical turbine blade; Step 2: Perform fatigue testing on the target location area under different cyclic load conditions to obtain the turbine blade status of the corresponding mode, where the turbine blade status includes turbine resonance failure, turbine blade strain, turbine blade damage, and turbine blade fracture; Step 3: Obtain the blade temperature and supercharger speed when the turbine fails due to resonance, obtain the blade temperature and supercharger speed when the turbine blade is strained, obtain the blade temperature and supercharger speed when the turbine blade is damaged, and obtain the blade temperature and supercharger speed when the turbine blade is broken; Step 4: Couple different turbine blade states to obtain the total life time of turbine blade fatigue, input the total life time into the life prediction model, output the safety factor and verify it.

[0021] In the above technical solution, in the first step, based on an existing three-dimensional turbine model, the turbine blades and turbine disk of the turbocharger are connected via a tenon-tooth assembly. Finite element method segmentation is then performed based on the three-dimensional turbine model. After the finite element method segmentation, the pressure and velocity fields are input to obtain the stress distribution contour map. Therefore, in step 1, the target location area is obtained based on the distribution contour maps of the historical turbine blade pressure and velocity fields. The thermal-mechanical coupling process is simulated using the transient thermodynamics module of the finite element software ABAQUS to extract the stress and temperature fields. The loads on the turbine blades are primarily centrifugal force, thermal stress, and aerodynamic forces. Since the magnitude of the centrifugal force is determined by the turbocharger speed, the calculation state is determined based on the actual situation, combined with temperature stress and aerodynamic forces. Since centrifugal force and thermal stress are the main causes of turbine blade fatigue changes during turbocharger operation, this application primarily considers the durability analysis under the coupled effects of centrifugal force and thermal stress.

[0022] In the second step, considering that the coupling of centrifugal force and temperature stress will cause blade fatigue, which in turn affects the durability of the blade, it is necessary to perform fatigue testing on the target position area under different cyclic load conditions. The fatigue tests of different cyclic load conditions are used to obtain the turbine blade status of the corresponding mode. The change in the turbine blade status is mainly the obvious failure change of the turbine blade. The fatigue modes that effectively identify the failure change include turbine resonance failure, turbine blade strain, turbine blade damage, and turbine blade fracture. These four turbine blade status conditions reflect the fatigue failure of the turbine blade, which helps to quickly judge the durability of the blade.

[0023] The third step is to obtain the main reference values ​​for the four types of turbine blade state changes based on the four types of turbine blade state changes. These are the blade temperature and supercharger speed when the turbine fails under resonance, the blade temperature and supercharger speed when the turbine blade is strained, the blade temperature and supercharger speed when the turbine blade is damaged, and the blade temperature and supercharger speed when the turbine blade is broken. This allows for accurate acquisition of reference value information for the target position of the turbine blade. Among them, one implementation method in step three is specifically: S1. Obtain the target position area of ​​the turbine blade: The turbine blades are divided into several unit cells using the grid method; Digitally measure the temperature of several unit cells in the turbine blade, set several temperature ranges from small to large, and use RGB equivalent color temperature to represent different temperature ranges; Select the cell corresponding to the highest equivalent color temperature RGB within the temperature range as the target location area, and count the total number of cells in the target location area ; S2. Statistical target location area The temperature set within a cell ; Calculate the average value of the temperature set ; S3, when the turbine resonance fails, the temperature reaches , get the supercharger speed As the first limit value; When the turbine blades are strained, the temperature reaches , get the supercharger speed As the second limit value; When the turbine blade is damaged, the temperature reaches , get the supercharger speed As the third limit value; When the turbine blade breaks, the temperature reaches , get the supercharger speed as the fourth limit value.

[0024] In the above technical solution, during the actual fatigue test of a turbocharger, the load conditions on the working blades during the use of the turbocharger are mainly considered. Since the loads are complex and variable, it is neither possible nor necessary to calculate the loads on the blades at any time and the stress field generated. Therefore, as long as the key positions of the turbine blades are selected, the area of ​​the maximum stress field is used as one of the reference values, that is, the temperature value corresponding to the stress at this position also needs to be used as the main reference value. Usually, the maximum stress occurs at the root of the turbine blade. Based on this, see Figure 2-3 As shown in the figure, the method for obtaining the temperature when the blade reaches the corresponding state is as follows: first, the target position area of ​​the turbine blade is obtained. Given the three-dimensional structure of the turbine blade distribution in the turbocharger, the blade surface unit grid is set by the grid method. The unit grid is a pixel point. The elliptical area at the root of the turbine blade is divided into a number of cells with the turbocharger rotation axis as the center of the annular area (see Figure 3 The main method is to use an electromagnetic exciter to apply a cyclic load mode, and cooperate with the induction heating system to simulate and obtain the corresponding temperature field. The turbine blade is digitally measured in combination with the imported three-dimensional structure to obtain the temperature of several unit cells in the turbine blade, and several temperature ranges are set from small to large. Different temperature ranges are represented by equivalent color temperature RGB; the higher the temperature, the greater the R ratio, the redder the color, and the higher the temperature ( Figure 2 The larger the proportion of B, the bluer the color and the higher the temperature ( Figure 2 Medium color light); and select the highest temperature range ( Figure 2The cell corresponding to the equivalent color temperature RGB of the darkest color in the target position area is taken as the target position area, and the total number of cells in the target position area is counted; Secondly, after obtaining the target area range and counting the total number of cells in the target area, it is always greater than , then count the number of The temperature set within a cell ; Calculate the average value of the temperature set This process ensures that the temperature value deviation of the target blade state is small (the smaller the target area range is, the smaller the temperature deviation is), weakens or even ignores the complex stress changes of the blade caused by temperature, and ensures the subsequent further prediction of the fatigue life of the turbine blades in different turbine blade states, reduces the interference of temperature stress on the results, and reduces the interference of complex factors on the durability of the turbine blades under complex changes.

[0025] Finally, the fatigue test targets under different cyclic load conditions are calculated: when the turbine fails at resonance, the temperature reaches , get the supercharger speed As the first limit value; when the turbine blade strain temperature reaches , get the supercharger speed As the second limit value; when the turbine blade is damaged, the temperature reaches , get the supercharger speed As the third limit value; when the turbine blade breaks, the temperature reaches , get the supercharger speed As the fourth limit value, the above method realizes the accurate selection of the turbine state change region by determining the target position region of the turbine blades, and obtains the corresponding limit value so as to facilitate the determination of fatigue life according to the limit value in the next step.

[0026] As an embodiment of the present invention, there are three modes of cyclic load conditions, including: a centrifugal force cyclic mode, a temperature load coupled cyclic mode, and a centrifugal force and temperature load coupled combined cyclic mode.

[0027] In the above technical solution, different target data are obtained through different cyclic load conditions. The different target data obtained through different conditions can comprehensively feedback the impact of the coupling of centrifugal force and temperature load on the life of the turbine blades. In addition, different cyclic load conditions lead to different fatigue changes in the blades: Low cycle fatigue (LCF): simulates centrifugal force-dominated loads (stress amplitude > 50% of yield strength), with a number of cycles < 10 4 times, used to obtain turbine blade damage and fracture data; High cycle fatigue (HCF): simulates aerodynamic vibration load (stress amplitude < 20% of yield strength), number of cycles > 106 times, used to obtain turbine blade strain data; Combined fatigue: superimpose low-cycle and high-cycle loads (such as centrifugal force and vibration combination) to simulate turbine resonance failure, cycle number 10 4 -10 6 Second-rate.

[0028] The fourth step is to obtain the total fatigue life of the turbine blades by coupling different turbine blade states after defining a series of test conditions and collecting test data. The total life time is input into the life prediction model to output the safety factor and verify it.

[0029] As an embodiment of the present invention, the method for obtaining the fatigue life time of turbine blades in different turbine blade states in step 4 is: Obtain different cyclic load conditions to record the state parameters corresponding to different turbine blade states and the number of cycles recorded when the damage corresponds to different turbine blade states : The number of cycles of turbine resonance failure is recorded as The number of cycles of turbine blade strain is recorded as The number of cycles of turbine blade damage is recorded as The number of cycles of turbine blade fracture is recorded as ; The state parameters corresponding to different turbine blade states include: recording the resonant frequency of turbine resonance failure, recording the strain amplitude of turbine blade strain, recording the crack length of turbine blade damage, and recording the corresponding strength of turbine blade fracture; using these parameters as the judgment criteria for subsequent changes in turbine blade state, so as to obtain the corresponding temperature and supercharger speed; the above parameters are obtained by obtaining the crack length of turbine blade and the position strength of turbine blade fracture according to the centrifugal force cycle mode; obtaining the strain amplitude of turbine blade strain according to the temperature load coupling cycle mode; and obtaining the resonant frequency of turbine resonance failure according to the centrifugal force and temperature load coupling composite cycle mode.

[0030] Then, the total number of times the limit value is exceeded is recorded until the corresponding turbine blade state is reached. , obtain the multi-mode damage coupling model for cyclic loading cases , the calculation formula is: ;in, is the total damage value of the turbine blade, which is composed of low-cycle / high-cycle fatigue damage, creep damage and crack extension damage. Among the low-cycle / high-cycle fatigue damage: The first stress of the turbine blade under the current cyclic load mode The cumulative number of cycles exceeding the limit value; and ∈ ; The number of cycles (fatigue life) recorded when the turbine blade reaches the damage corresponding to the turbine blade state under the stress of the current cyclic load mode; in creep damage: For the The creep strain rate (strain increment per unit time) that exceeds the limit value for the second time; is the number of creep life cycles, which is related to the current creep strain rate and temperature Related; Crack propagation damage: is the crack length (a variable that grows with time); is the crack growth life times, which is related to the current crack length and temperature Related; is the time interval from the initial length to the critical length of the crack; By formula Calculate the total lifespan , To complete a cycle time.

[0031] In the above technical solution, first, different cyclic load conditions are obtained to record the state parameters corresponding to different turbine blade states; specifically, the resonance frequency of the turbine resonance failure (such as the first-order bending frequency of 50-200Hz at the blade root) is identified through frequency response testing, and the number of cycles of first crack initiation is recorded. ; The strain amplitude when monitoring turbine blade strain through strain gauges ( =0.1%-0.5%), and count the number of cycles when the cumulative damage reaches the critical value ; Detect the length of micro cracks in turbine blades by CT scanning ( =0.1-1mm), combined with Paris law to calculate the number of cycles for crack growth to reach the critical size ; Record the number of cycles of turbine blade fracture instantaneously by high-speed video , the corresponding residual strength is lower than the design threshold, and its strength is generally set to be less than 0.6 times the standard strength; Then, based on the above state values, the statistical cutoff is obtained and the total number of times the limit value is exceeded is recorded. , obtain the multi-mode damage coupling model for cyclic loading cases: ; By calculating the state of the turbine blades when the limit value is exceeded, the state exceeding the limit value is more likely to cause fatigue failure of the turbine blades. The more the limit value is exceeded, the greater the damage value of the turbine blades. The low frequency and high frequency are obtained according to the corresponding state values: , creep damage: and crack extension damage: By counting the cases exceeding the limit value, it is helpful to ensure the subsequent optimization of the life prediction range according to the life prediction model and reduce the prediction deviation value; Finally, through the formula Calculate the total lifespan , To complete a cycle time.

[0032] As an embodiment of the present invention, the calculation process of obtaining the safety factor based on the life prediction model is as follows: By formula Calculate the safety factor ; is the total life expectancy prediction; Enter a value for Total Life; is the dispersion coefficient, ranging from 1.5 to 2.0; is the environmental correction factor, which is 0.8-0.9 in high temperature oxidation environment.

[0033] In the above technical solution, the safety factor is used to determine the life benchmark of the life prediction model.

[0034] As an embodiment of the present invention, the method for verifying the safety factor is: Apply equivalent loads (such as centrifugal force + thermal load combined loading) on ​​a rotating test bench to monitor crack initiation and propagation; Eddy current testing (ECT) and infrared thermal imaging are used to verify the predicted crack location (error < 2mm); Specifically, the life prediction model is modified by introducing machine learning (such as XGBoost) to perform online correction of the prediction error. The calculation formula is:

[0035] in, is the fatigue life prediction value, unit: number of cycles; is the model baseline fatigue life, unit: number of cycles; is the temperature sensitivity coefficient; is the temperature change; is the reference temperature; In the above technical solution, the modification process of the life prediction model is analyzed by taking the turbine blade of an aircraft engine as an engineering application case: First, input parameters: Material: GH4169 (yield strength 980MPa, fatigue limit 280MPa) Working condition: low cycle fatigue: , times; high cycle fatigue: , times; compound fatigue: (Low-week) combination (High cycle); Load spectrum: rotation cycle = 500 times / day; Prediction results: Turbine resonance failure: =8,300 times (forecast error + 9.2%); Turbine blade strain: =12500 times (error -7.5%); Turbine blade damage: =25,000 times (error +11.8%); Turbine blade fracture: =48,000 times (error -6.3%); Comprehensive safety factor: =1.85 (design life 26000 times); Verification data: After 20,000 actual cycles, the crack length at the blade root was 0.8 mm (predicted value 0.75 mm, error +6.7%). Disassembly verification: the resonance failure life deviated from the prediction by ±8%, and the fracture life deviated by ±5%.

[0036] As an embodiment of the present invention, the steps of fatigue testing are as follows: First, test equipment configuration; use an electromagnetic vibration table or high-frequency fatigue testing machine, configure a closed-loop control system to monitor amplitude (accuracy ± 0.01mm) and strain (accuracy ± 1 ), and integrate temperature sensors and speed sensors to synchronously collect environmental parameters; Then, a multi-cycle load condition mode test process is used: the crack length of the turbine blade and the position strength of the turbine blade fracture are obtained according to the centrifugal force cycle mode; the strain amplitude of the turbine blade strain is obtained according to the temperature load coupling cycle mode; and the resonance frequency of the turbine resonance failure is obtained according to the centrifugal force and temperature load coupling composite cycle mode.

[0037] Mode 1: Centrifugal circulation mode Obtain the crack length and position strength of the turbine blade fracture, and combine the fracture morphology analysis (SEM observation) to determine the correlation between the fracture source location and the load amplitude (such as high stress amplitude leading to transgranular fracture); determine the blade's first-order natural frequency (such as 330-824Hz) through a sweep frequency test, apply a cyclic load, i.e., a low-cycle fatigue load, at the resonant frequency, and record the number of cycles before the blade is damaged and before the blade fractures. 、 and the position strength corresponding to the failure position (such as blade root cracks, blade crown peeling); Mode 2: Temperature load coupled cycle mode Obtain the strain amplitude of the turbine blade strain and quantify the effect of thermal expansion coefficient differences on local strain through strain gauge data and temperature field data; additional strain caused by temperature differences in the target area of ​​the blade (strain amplitude 0.001-0.01 / s), apply high-cycle fatigue loads at non-resonant frequencies, and record the number of cycles before the blade strains. ;Monitor strain gauge data and analyze crack initiation rates in strain localization areas; Mode 3: Centrifugal force and temperature load coupling combined cycle mode Obtain the resonant frequency of turbine resonance failure, establish the corresponding relationship between resonant frequency and supercharger speed (e.g., 8000 rpm corresponds to 533 Hz), analyze the effect of temperature on material stiffness (elastic modulus decreases at high temperatures, causing resonant frequency shift), apply a composite fatigue load of centrifugal force and vibration, and record the number of cycles before blade strain. ; Finally, the status is classified and recorded; the failure mode is classified and recorded according to the test results: fracture of the turbine blade, crack propagation, resonance failure and the first crack generation, and the temperature, speed, and load time domain / frequency domain data under the corresponding working conditions are saved.

[0038] The various embodiments in this specification are described in a progressive manner. Similar portions between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the device, apparatus, and non-volatile computer storage medium embodiments are generally similar to the method embodiments, so their descriptions are relatively simplified. For relevant details, refer to the descriptions of the method embodiments.

[0039] The foregoing description is of specific embodiments of this specification. Other embodiments are within the scope of the accompanying documents. In some cases, the actions or steps described in this application can be performed in an order different from that shown in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or the sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0040] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined in this application, they should all fall within the scope of protection of the present invention.

Claims

1. A method for testing the durability of a turbocharger turbine, characterized in that: The method comprises: Step 1: Obtain the target location area based on the distribution cloud map of the pressure field and velocity field of the historical turbine blade; Step 2: Perform fatigue testing on the target location area under different cyclic load conditions to obtain turbine blade states of the corresponding modes, wherein the turbine blade states include turbine resonance failure, turbine blade strain, turbine blade damage, and turbine blade fracture; Step 3: Based on fatigue testing, determine the blade temperature and supercharger speed at turbine resonance failure, the blade temperature and supercharger speed at turbine blade strain, the blade temperature and supercharger speed at turbine blade damage, and the blade temperature and supercharger speed at turbine blade fracture to determine limit values ​​for different turbine blade states; Step 4: Calculate the total fatigue life of the turbine blades by coupling different turbine blade states and their limit values. Input the total life into the life prediction model to output the safety factor and verify it.

2. The durability test method for a turbocharger turbine according to claim 1, characterized in that: There are three modes of the cyclic load conditions, including: a centrifugal force cyclic mode, a temperature load coupled cyclic mode, and a centrifugal force and temperature load coupled combined cyclic mode.

3. The durability test method for a turbocharger turbine according to claim 2, characterized in that: The step three includes: S1. Obtain the target position area of ​​the turbine blade: The turbine blades are divided into several unit cells using the grid method; Digitally measure the temperature of several unit cells in the turbine blade, set several temperature ranges from small to large, and use RGB equivalent color temperature to represent different temperature ranges; Select the cell corresponding to the highest equivalent color temperature RGB within the temperature range as the target location area, and count the total number of cells in the target location area ; S2. Statistical target location area The temperature set within a cell ; Calculate the average value of the temperature set ; S3. Obtain the temperature of the turbine blades in the current cyclic load mode ; and obtain the supercharger speed as a limiting value.

4. The durability test method for a turbocharger turbine according to claim 2, characterized in that: The method for obtaining the total fatigue life of turbine blades by coupling different turbine blade states in step 4 is: Obtaining different cyclic load conditions to record state parameters corresponding to different turbine blade states and the number of cycles recorded when damage corresponding to different turbine blade states is recorded; The state parameters corresponding to different turbine blade states include: recording the resonance frequency of turbine resonance failure, recording the strain amplitude of turbine blade strain, recording the crack length of turbine blade damage, and recording the position strength of turbine blade fracture; The crack length of the turbine blade and the position strength of the turbine blade fracture are obtained according to the centrifugal force circulation mode; the strain amplitude of the turbine blade strain is obtained according to the temperature load coupling circulation mode; and the resonance frequency of the turbine resonance failure is obtained according to the centrifugal force and temperature load coupling composite circulation mode.

5. The durability test method for a turbocharger turbine according to claim 4, characterized in that: When the statistics reach the corresponding turbine blade state, the total number of times exceeding the limit value is recorded , obtain the multi-mode damage coupling model for cyclic loading cases , the formula is: in, is the total damage value of the blade, which is composed of the coupling of low-cycle / high-cycle fatigue damage, creep damage and crack extension damage; Low-cycle / high-cycle fatigue damage: The first stress of the turbine blade under the current cyclic load mode The cumulative number of cycles exceeding the limit value; and ∈ ; The number of cycles recorded when the turbine blade reaches the damage corresponding to the turbine blade state under the stress of the current cyclic load condition mode; Creep damage: For the The creep strain rate exceeds the limit value for the second time; is the number of creep life cycles, which is related to the current creep strain rate and temperature Related; Crack propagation damage: is the crack length; is the crack growth life times, which is related to the current crack length and temperature Related; is the time interval from the initial length to the critical length of the crack; By formula Calculate the total lifespan , To complete a cycle time.

6. The durability test method for a turbocharger turbine according to claim 1, characterized in that: The calculation process for obtaining the safety factor based on the life prediction model is as follows: By formula Calculate the safety factor ; is the total life expectancy prediction; Enter a value for Total Life; is the dispersion coefficient; is the environmental correction factor.

7. The durability test method for a turbocharger turbine according to claim 6, characterized in that: The method for verifying the safety factor is: Apply equivalent loads on a rotating test bench to monitor crack initiation and growth; Eddy current testing and infrared thermal imaging are used to verify the predicted crack location error; Correct the lifespan prediction model: Use machine learning to correct prediction errors online.

8. The durability test method for a turbocharger turbine according to claim 7, characterized in that: The correction method for correcting the life prediction model is: in, is the fatigue life prediction value, unit: number of cycles; is the model baseline fatigue life, unit: number of cycles; is the temperature sensitivity coefficient; is the temperature change; is the reference temperature.

Images