Accelerated thermal shock test method for air-cooled turbine guide vane of combustion-driven compressor unit

Abstract

The invention discloses an accelerated thermal shock test method for an air-cooled turbine guide vane of a combustion-driven compressor unit. The accelerated thermal shock test method comprises the following steps: step 1, determining gas thermal parameters of a test blade; 2, determining the number of single group of test blades; 3, determining the number of test groups; 4, determining a temperature load spectrum of the air-cooled turbine guide vane; step 5, carrying out a temperature debugging test on the air-cooled turbine guide vane; step 6, officially accelerating the thermal shock test; step 7, evaluating the blade state of the air-cooled turbine guide vane test; step 8, determining the thermal fatigue cycle resistance of the air-cooled turbine guide vane; step 9, performing simulation calculation on the thermal fatigue resistant cycle capability of the air-cooled turbine guide vane; and step 10, analyzing the validity of a test result. By adopting the design method provided by the invention, the thermal fatigue resistance of the air-cooled turbine guide vane of the combustion-driven compressor unit can be examined in a part state with lower technical risk and investment and under the condition close to a real working environment.

Description

Technical Field

[0001] This invention belongs to the field of marine gas turbines, specifically relating to a method for accelerated thermal shock testing of air-cooled turbine guide vanes in a gas-driven compressor unit. Background Technology

[0002] Gas turbines have advantages such as high power density, fast start-up speed, and flexible fuel supply. They are widely used in industrial and offshore platform power generation, natural gas pipeline pressurization, petrochemical and metallurgical fields, and are also widely used as the main power plant of ships.

[0003] To achieve higher cycle efficiency and greater power, modern high-performance gas turbines continuously increase the inlet gas temperature (high-pressure turbine inlet temperature). With this increasing inlet temperature, the operating temperature far exceeds the melting point of the blade materials. For example, the inlet gas temperature of the most advanced gas turbines currently in operation has reached 1600℃, and the inlet temperature of advanced aero-engine turbines exceeds 1800℃. Ensuring the safe and reliable operation of gas turbine blades under such high temperatures for extended periods relies on three main measures: firstly, continuously improving the heat resistance of turbine blade materials; secondly, employing advanced cooling technologies to reduce blade temperature; and thirdly, continuously improving the heat insulation effect of the turbine blade's thermal insulation coating. In recent years, the increase in turbine inlet temperature is primarily attributed to improvements in turbine cooling design, followed by advancements in high-performance heat-resistant alloys and coating materials, as well as improvements in manufacturing processes. Clearly, turbine blade cooling plays a crucial role in increasing turbine inlet temperature and improving gas turbine performance. However, this also leads to increasingly higher thermal loads on turbine blades, posing significant challenges to blade reliability.

[0004] Furthermore, during operation, the gas turbines used in gas-driven compressor units experience significant temperature load changes (especially thermal shock loads) on their turbine blades during startup, acceleration, deceleration, and shutdown. These temperature load changes easily lead to thermal shock fatigue in the air-cooled turbine blades, greatly reducing the service life of the high-pressure turbine blades and affecting the reliability and safety of the unit. Coupled with the special operating characteristics of prolonged operation under medium-to-high operating conditions, start-up and shutdown further exacerbate thermal fatigue in the air-cooled turbine blades, making it an unavoidable factor in the design and testing of gas-driven compressor units.

[0005] In recent years, although scholars and researchers both domestically and internationally have conducted extensive research on the efficient cooling design of turbine blades for aero-engines and gas turbines, and some studies on thermal shock testing of aero-engine turbine blades have been carried out, leading to some understanding of improving turbine blade cooling performance and revealing the internal cooling flow mechanism of turbine blades, these studies have not focused on how to conduct thermal shock tests on air-cooled turbine blades for gas turbines used in gas turbine compressor units to improve their thermal fatigue resistance. There are also few reports on thermal shock testing of cooled turbine blades for gas turbine compressor units. Therefore, conducting thermal fatigue testing on air-cooled turbine blades for gas turbine compressor units has extremely important practical value and scientific significance. In particular, for the guide vanes and moving blades of air-cooled turbines in gas turbine compressor units that operate under medium-to-high operating conditions and frequent load changes for extended periods, how to conduct scientific, reasonable, and targeted thermal fatigue testing has become an urgent technical problem to be solved in the development of marine gas turbines.

[0006] Currently, most designers and testers directly install the air-cooled turbine guide vanes of the test object in the environment of a gas turbine unit for gas-driven compressor units, or use the thermal shock test method for aero-engine turbine blades to conduct thermal shock tests on the turbine blades of gas-driven compressor units. However, testing the thermal shock characteristics of air-cooled turbine guide vanes in the environment of a gas turbine unit poses a significant technical risk to the reliability of the entire unit. Failure of the air-cooled turbine guide vane results in severe damage to the entire unit, leading to excessive costs. Furthermore, the test requires testing the air-cooled turbine guide vane on a test bench, and the unit must be disassembled afterward to conduct blade condition analysis and inspection. The process of setting up and disassembling the entire unit on the test bench is lengthy and requires substantial investment. Using the thermal shock test method for aero-engine turbine blades to conduct thermal shock tests on the turbine blades of gas-driven compressor units has the disadvantage of not reflecting the true operating characteristics of the air-cooled turbine guide vanes of the gas-driven compressor unit. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides an accelerated thermal shock test method for air-cooled turbine guide vanes of gas-driven compressor units. This method allows for the assessment of the thermal fatigue resistance of air-cooled turbine guide vanes of gas-driven compressor units under conditions that are close to real-world working environments, with lower technical risks and investment, while the parts are in their component state.

[0008] The objective of this invention is achieved through the following technical solution: a method for accelerating thermal shock testing of air-cooled turbine guide vanes in a gas-driven compressor unit, comprising the following steps:

[0009] Step 1: Determine the aero-thermal parameters of the test blade;

[0010] Step 2: Determine the number of blades in a single test group;

[0011] Step 3: Determine the number of experimental groups;

[0012] Step 4: Determine the temperature load spectrum of the air-cooled turbine guide vanes;

[0013] Step 5: Temperature adjustment test of air-cooled turbine guide vanes;

[0014] Step 6: Formal accelerated thermal shock test;

[0015] Step 7: Evaluation of the condition of the air-cooled turbine guide vane test blade;

[0016] Step 8: Determine the thermal fatigue cycle resistance of the air-cooled turbine guide vanes;

[0017] Step 9: Simulation calculation of the thermal fatigue cycle resistance of the air-cooled turbine guide vanes;

[0018] Step 10: Validity analysis of test results.

[0019] Preferably, in step 2, the number of test blades in a single group is determined based on the ratio of the maximum gas flow rate of the gas-cooled turbine guide vane thermal shock test bench to the gas flow rate of a single gas-cooled turbine blade passage in the gas-thermal parameters of the test blade.

[0020] Preferably, in step 3, the number of test groups is determined according to the following formula:

[0021]

[0022] Where, N s,s N represents the number of blades in a single test group. s,all This represents the total number of air-cooled turbine guide vanes that require thermal shock testing.

[0023] Preferably, in step 4, the temperature load spectrum curve of the air-cooled turbine guide vane is determined according to the following rules: based on the average temperature of the mid-section of the air-cooled turbine guide vane under the highest operating load condition and the average temperature of the mid-section of the air-cooled turbine guide vane under no-load condition, which are determined in step 1, combined with the lowest outlet temperature that the test bench burner can achieve under the lowest stable combustion condition, and the lowest average temperature that the mid-section of the air-cooled turbine guide vane can reach under this condition, the temperature load spectrum of the air-cooled turbine guide vane is given; wherein, the duration of rapid heating is not greater than the time required for the gas turbine of the gas-driven compressor unit to rapidly rise from no-load to the highest operating load condition during long-term operation. The time taken, the highest temperature is equal to the average temperature of the mid-section of the air-cooled turbine guide vane under the highest operating load condition, the duration of the highest temperature is determined according to the time it takes for the blade to reach a stable highest temperature under the highest operating load condition for a long time, the duration of rapid cooling is not greater than the time it takes for the gas turbine to rapidly cool down from the highest operating load condition for a long time to no load, the lowest temperature is the minimum value of the average temperature of the mid-section of the air-cooled turbine guide vane under no load condition and the lowest average temperature that the mid-section of the air-cooled turbine guide vane can reach under the lowest stable combustion condition of the test bench burner, the duration of the lowest temperature is determined according to the time it takes for the blade to reach a stable lowest temperature under no load condition.

[0024] Preferably, in step 5, a thermocouple is arranged in the cross section of a certain air-cooled turbine guide vane and installed on the test bench as a test blade. According to the air-cooled turbine guide vane temperature load spectrum curve given in step 4, the fuel supply flow rate, gas supply flow rate, gas supply pressure, cooling air supply pressure, and cooling air supply flow rate of the test bench are adjusted to ensure that the highest and lowest temperature load states in the air-cooled turbine guide vane temperature load spectrum can be achieved. The fuel supply flow rate, gas supply flow rate, gas supply pressure, cooling air supply pressure, and cooling air supply flow rate parameters of the test bench under the two load states are recorded. The test state control is carried out according to these parameters during the subsequent formal test.

[0025] Preferably, in step 6, the state of the air-cooled turbine guide vane before the test is photographed and recorded; the test vane with thermocouple installed in step 5 is removed and replaced with an air-cooled turbine guide vane without thermocouple; based on the blade temperature test completed in step 5, according to the parameters of burner oil supply flow rate, burner gas supply flow rate, burner gas supply pressure, cooling air supply pressure, and cooling air supply flow rate under the two load conditions of the highest and lowest temperatures determined by the test, the accelerated thermal shock test of the air-cooled turbine guide vane is carried out according to the temperature load spectrum curve of the air-cooled turbine guide vane determined in step 4.

[0026] Preferably, in step 7, during the test in step 6, after every 500 cycles, the surface condition of the air-cooled turbine guide vane test blade is checked and analyzed, and the condition of the air-cooled turbine guide vane test blade after the current number of cycles is photographed and recorded. If a crack with a length exceeding 2mm appears on the surface, the test ends, and the number of cycles completed is the thermal fatigue cycle resistance of the test blade; if no crack appears on the surface, the test continues until a crack with a length exceeding 2mm appears, and the number of cycles is the thermal fatigue cycle resistance of the test blade.

[0027] Preferably, in step 8, the state of the air-cooled turbine guide vane test blades, which were checked, analyzed, photographed, and recorded at each stage before the test in step 6 and during the test in step 7, is compared and analyzed. Combined with the thermal fatigue cycle resistance of the test blades determined by the inspection and analysis during the test in step 7, the thermal fatigue cycle resistance of the air-cooled turbine guide vane is finally determined.

[0028] Preferably, in step 9, the temperature load spectrum determined in step 4 is input into the simulation calculation model for calculation, and its peak temperature T is obtained respectively. test,max Valley temperature T test,min The corresponding distributions of the first principal stress, first principal strain, and third principal strain, where the peak temperature T at the test point of the test section is... test,max The first principal stress and the first principal strain calculated under the working condition are denoted as σ1max and ε1, respectively. max The valley temperature T at the test section test point test,min The corresponding first principal stress, first principal strain, and third principal strain are denoted as σ1. min ε1 min ε3 min Under valley temperature conditions, the condition may primarily manifest as a compressive state, requiring the first principal strain ε1 under peak temperature conditions to be considered. max The first (ε1) under the valley temperature condition min ), the third (ε3) min The directions of the principal strains are compared, and the principal strain that is the same as or opposite to the direction of the first principal strain under the peak temperature condition is selected as the principal strain under the valley temperature condition, denoted as:

[0029] ε min =[ε1 max , (ε1 min ε3 min (2)

[0030] Its principal strain range is:

[0031] Δε 主 =ε1 max -ε min (3)

[0032] Substituting this into the following formula, we obtain the number of cycles, i.e., the thermal fatigue cycle resistance N of the high-pressure turbine guide vane. f :

[0033]

[0034] In the formula, b is the fatigue strength index, c is the fatigue ductility index, and σ f ε is the fatigue strength coefficient. f Where E is the fatigue ductility coefficient, E is the elastic modulus, and N is the fatigue ductility coefficient. f For resistance to thermal fatigue cycles.

[0035] Preferably, in step 10, the thermal fatigue cycle resistance N calculated in step 9 is used as the reference value. f N obtained from the experiment in step 8 test In comparison, if N f / N test ≥5, then N test This refers to the thermal fatigue cycle resistance of the high-pressure turbine guide vanes; if N f / N test If the result is less than 5, the test plan needs to be readjusted and the test conducted.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] This invention provides an accelerated thermal shock test method for air-cooled turbine guide vanes of gas-driven compressor units. Based on the operating characteristics of gas-driven compressor unit turbines, which operate under medium-to-high operating conditions and frequent load changes over extended periods, the test process has been newly organized. This method helps to standardize the accelerated thermal shock test process for air-cooled turbine guide vanes of gas-driven compressor units, and is more likely to yield air-cooled turbine guide vanes that meet usage requirements. Using this test method, the thermal fatigue resistance of air-cooled turbine guide vanes of gas-driven compressor units can be assessed in part condition with lower technical risks and investment, and under conditions close to real-world operating environments. It eliminates the need for complex whole-machine environments, avoiding the significant manpower and material resources required for extensive loading and unloading of the entire machine onto test benches and disassembly for inspection. Attached Figure Description

[0038] Figure 1 This is a flowchart of an accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit according to the present invention;

[0039] Figure 2 This is a temperature load spectrum curve of the air-cooled turbine guide vane in an embodiment of the present invention. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0041] like Figure 1 As shown, the technical solution of the present invention provides a method for accelerating thermal shock testing of air-cooled turbine guide vanes in a gas-driven compressor unit, comprising the following steps:

[0042] Step 1: Determine the aerothermal parameters of the test blade: Based on the temperature field results given by the design and calculation of the air-cooled turbine guide vane, the average temperature T of the mid-section of the air-cooled turbine guide vane under the maximum operating load condition for a long period of time is given. s,f,ave The average temperature T of the mid-section of the air-cooled turbine guide vane under no-load conditions s,e,ave And the gas flow rate G of a single air-cooled turbine blade passage under test conditions. s,g Gas total temperature Total gas pressure Cooling air total pressure Cooling air total temperature Single air-cooled turbine guide vane cooling airflow G s,c .

[0043] Step 2: Determine the number of blades in a single test group; based on the gas flow rate G of a single air-cooled turbine blade passage in the gas-thermal parameters of the test blades determined in Step 1. s,g Combined with the maximum gas flow rate G of the air-cooled turbine guide vane thermal shock test bench T,g,max If G T,g,max / G s,g If ≥4, then the number of leaves N in a single test group s,s Take 3; if 3 ≤ G T,g,max / G s,g If the number of leaves in a single test group is less than 4, then the number of leaves in the single test group is N. s,s Take 2; if 2≤G T,g,max / G s,g If the number of leaves in a single test group is less than 3, then the number of leaves in the single test group is N. s,s Take 1.

[0044] Step 3: Determine the number of experimental groups: The number of experimental groups is determined according to the following formula:

[0045]

[0046] Where, N s,s N represents the number of blades in a single test group. s,all This represents the total number of air-cooled turbine guide vanes that require thermal shock testing.

[0047] Step 4: Determine the temperature load spectrum of the air-cooled turbine guide vane: Based on the aerothermal parameters of the test blade determined in Step 1, the average temperature T of the mid-section of the air-cooled turbine guide vane under the highest operating load condition during long-term operation. s,f,ave The average temperature T of the mid-section of the air-cooled turbine guide vane under no-load conditions s,e,ave The lowest outlet temperature T that the burner on the test bench can achieve under the lowest stable combustion state is determined by... comb,min The lowest average temperature T that the cross section of the air-cooled turbine guide vane can reach under this condition. s,Tmin,ave Given the temperature load spectrum of the air-cooled turbine guide vane: rapid heating duration t test,heat The time t taken for the gas turbine of the gas-driven compressor unit to rapidly increase from no-load to the maximum operating load for long-term operation is not greater than the time t. load,0-max The highest temperature T test,max =T s,f,ave Duration of highest temperature t test,max The duration of the highest temperature is determined by the time it takes for the blade to reach a stable maximum temperature under the highest operating load during long-term operation. Generally, the duration of the maximum temperature is t. test,max =2~3s, rapid cooling duration t test,cool No greater than the time t taken for the gas turbine to rapidly reduce from its peak operating load during prolonged operation to no load. load,max-0 Minimum temperature T test,min =min(T) s,e,ave ,T s,Tmin,ave The duration of the lowest temperature, t test,min The duration of the minimum temperature is determined based on the time it takes for the blades to reach a stable minimum temperature under no-load conditions. Generally, the duration of the minimum temperature is t. test,min =2~3s, plot the load spectrum curve, as follows Figure 2 As shown.

[0048] Step 5: Temperature Adjustment Test of Air-Cooled Turbine Guide Blade: A thermocouple is placed at the mid-section of a certain air-cooled turbine guide blade and installed on the test bench as an adjustment blade. According to the temperature load spectrum curve of the air-cooled turbine guide blade given in Step 4, the fuel supply flow rate G of the burner on the test bench is adjusted. T,oil Burner gas supply flow rate G T,g Burner gas supply pressure Cooling air supply pressure Cooling air supply flow rate G T,c This ensures that the highest temperature T in the temperature load spectrum of the air-cooled turbine guide vane can be achieved. test,max and lowest temperature T test,min Two load conditions (deviation not exceeding ±1%) were applied, and the fuel supply flow rate G of the burner on the test bench was recorded under both load conditions. T,oil Burner gas supply flow rate G T,g Burner gas supply pressure Cooling air supply pressure Cooling air supply flow rate G T,c These parameters will be used to control the test status during subsequent formal tests.

[0049] Step 6: Formal Accelerated Thermal Shock Test: Take photos and record the state of the air-cooled turbine guide vane before the test; remove the test blade with thermocouple installed in Step 5 and replace it with an air-cooled turbine guide vane without thermocouple; based on the blade temperature test completed in Step 5, determine the highest temperature T based on the test. test,max and lowest temperature T test,min Burner fuel supply flow rate G under two load conditions T,oil Burner gas supply flow rate G T,g Burner gas supply pressure Cooling air supply pressure Cooling air supply flow rate G T,c The parameters were determined according to the temperature load spectrum curve of the air-cooled turbine guide vane in step 4, and the accelerated thermal shock test of the air-cooled turbine guide vane was carried out.

[0050] Step 7: Evaluation of the condition of the air-cooled turbine guide vane test blade: During the test in Step 6, after every 500 cycles, the surface condition of the air-cooled turbine guide vane test blade is checked and analyzed. Photos are taken and the condition of the air-cooled turbine guide vane test blade after the current number of cycles is recorded. If a crack with a length exceeding 2mm appears on the surface, the test ends, and the number of cycles completed is the thermal fatigue cycle resistance of the test blade. If no crack appears on the surface, the test continues until a crack with a length exceeding 2mm appears, and the number of cycles is the thermal fatigue cycle resistance of the test blade.

[0051] Step 8: Determine the thermal fatigue cycle resistance of the air-cooled turbine guide vane: Compare and analyze the state of the air-cooled turbine guide vane test blades recorded by photos during each inspection, analysis and testing in Step 6 and during Step 7, and combine this with the thermal fatigue cycle resistance of the test blades determined by the inspection and analysis during Step 7 to finally determine the thermal fatigue cycle resistance of the air-cooled turbine guide vane.

[0052] Step 9: Simulation calculation of the thermal fatigue cycle resistance of the air-cooled turbine guide vane: Input the temperature load spectrum determined in Step 4 into the simulation calculation model for calculation, and obtain its peak temperature T. test,max Valley temperature T test,min The corresponding distributions of the first principal stress, first principal strain, and third principal strain, where the peak temperature T at the test point of the test section is... test,max The first principal stress and the first principal strain calculated under the working condition are denoted as σ1. max ε1 max The valley temperature T at the test section test point test,min The corresponding first principal stress, first principal strain, and third principal strain are denoted as σ1.min ε1 min ε3 min Under valley temperature conditions, the condition may primarily manifest as a compressive state, requiring the first principal strain ε1 under peak temperature conditions to be considered. max The first (ε1) under the valley temperature condition min ), the third (ε3) min The directions of the principal strains are compared, and the principal strain that is the same as or opposite to the direction of the first principal strain under the peak temperature condition is selected as the principal strain under the valley temperature condition, denoted as:

[0053] ε min =[ε1 max , (ε1 min ε3 min (2)

[0054] Its principal strain range is:

[0055] Δε 主 =ε1 max -ε min (3)

[0056] Substituting this into the following formula, we obtain the number of cycles, i.e., the thermal fatigue cycle resistance N of the high-pressure turbine guide vane. f :

[0057]

[0058] In the formula, b is the fatigue strength index, c is the fatigue ductility index, and σ f ε is the fatigue strength coefficient. f Where E is the fatigue ductility coefficient, E is the elastic modulus, and N is the fatigue ductility coefficient. f For resistance to thermal fatigue cycles.

[0059] Step 10, Validity Analysis of Test Results: The thermal fatigue cycle resistance N calculated in Step 9 is used as the basis for the test results. f N obtained from the experiment in step 8 test In comparison, if N f / N test ≥5, then N test This refers to the thermal fatigue cycle resistance of the high-pressure turbine guide vanes; if N f / N test If the result is less than 5, the test plan needs to be readjusted and the test conducted.

[0060] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for accelerating thermal shock testing of air-cooled turbine guide vanes in a gas-driven compressor unit, characterized in that: The method includes the following steps: Step 1: Determine the aero-thermal parameters of the test blade; Step 2: Determine the number of blades in a single test group; Step 3: Determine the number of experimental groups; Step 4: Determine the temperature load spectrum of the air-cooled turbine guide vanes; Step 5: Temperature adjustment test of air-cooled turbine guide vanes; Step 6: Formal accelerated thermal shock test; Step 7: Evaluation of the condition of the air-cooled turbine guide vane test blade; Step 8: Determine the thermal fatigue cycle resistance of the air-cooled turbine guide vanes; Step 9: Simulation calculation of the thermal fatigue cycle resistance of the air-cooled turbine guide vanes; Step 10: Validity analysis of test results.

2. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 1, characterized in that: In step 2, the number of test blades in a single group is determined based on the ratio of the maximum gas flow rate of the gas-cooled turbine guide vane thermal shock test bench to the gas flow rate of a single gas-cooled turbine blade cascade channel in the gas-thermal parameters of the test blade.

3. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 1, characterized in that: In step 3, the number of test groups is determined according to the following formula: Where, N s,s N represents the number of blades in a single test group. s,all This represents the total number of air-cooled turbine guide vanes that require thermal shock testing.

4. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 1, characterized in that: In step 4, the temperature load spectrum curve of the air-cooled turbine guide vane is determined according to the following rules: Based on the average temperature of the mid-section of the air-cooled turbine guide vane under the highest operating load condition and the average temperature of the mid-section of the air-cooled turbine guide vane under no-load condition, which are determined in the gas thermal parameters of the test blade in step 1, combined with the lowest outlet temperature that the test bench burner can achieve under the lowest stable combustion state, and the lowest average temperature that the mid-section of the air-cooled turbine guide vane can reach under this state, the temperature load spectrum of the air-cooled turbine guide vane is given; wherein, the duration of rapid heating is not greater than the time required for the gas turbine of the gas-driven compressor unit to rapidly rise from no-load to the highest operating load condition during long-term operation. The time, the highest temperature is equal to the average temperature of the mid-section of the air-cooled turbine guide vane under the highest operating load condition. The duration of the highest temperature is determined based on the time it takes for the blade to reach a stable highest temperature under the highest operating load condition for a long period of operation. The duration of rapid cooling is not greater than the time it takes for the gas turbine to rapidly cool down from the highest operating load condition for a long period of operation to no load. The lowest temperature is the minimum value between the average temperature of the mid-section of the air-cooled turbine guide vane under no load condition and the lowest average temperature that the mid-section of the air-cooled turbine guide vane can reach under the lowest stable combustion condition of the test bench burner. The duration of the lowest temperature is determined based on the time it takes for the blade to reach a stable lowest temperature under no load condition.

5. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 4, characterized in that: In step 5, a thermocouple is placed in the cross-section of a certain air-cooled turbine guide vane and installed on the test bench as a test blade. According to the air-cooled turbine guide vane temperature load spectrum curve given in step 4, the burner fuel flow rate, burner gas flow rate, burner gas pressure, cooling air pressure, and cooling air flow rate of the test bench are adjusted to ensure that the highest and lowest temperature load states in the air-cooled turbine guide vane temperature load spectrum can be achieved. The parameters of burner fuel flow rate, burner gas flow rate, burner gas pressure, cooling air pressure, and cooling air flow rate of the test bench under the two load states are recorded. The test state control is carried out according to these parameters during the subsequent formal test.

6. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 5, characterized in that: In step 6, photographs are taken and the state of the air-cooled turbine guide vane before the test is recorded; the test vane with thermocouple installed in step 5 is removed and replaced with an air-cooled turbine guide vane without thermocouple; based on the blade temperature test completed in step 5, the accelerated thermal shock test of the air-cooled turbine guide vane is carried out according to the burner oil flow rate, burner gas flow rate, burner gas pressure, cooling air pressure, and cooling air flow rate parameters under the two load conditions of the highest and lowest temperatures determined in the test, and according to the air-cooled turbine guide vane temperature load spectrum curve determined in step 4.

7. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 6, characterized in that: In step 7, during the test in step 6, after every 500 cycles, the surface condition of the air-cooled turbine guide vane test blade is checked and analyzed, and the state of the air-cooled turbine guide vane test blade after the current number of cycles is photographed and recorded. If a crack with a length of more than 2 mm appears on the surface, the test ends. The number of cycles completed is the thermal fatigue cycle resistance of the test blade. If no cracks appear on the surface, the test continues until cracks longer than 2 mm appear. The number of cycles is the thermal fatigue cycle resistance of the test blade.

8. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 7, characterized in that: In step 8, the state of the air-cooled turbine guide vane test blades, which were checked, analyzed, photographed, and recorded at each stage before the test in step 6 and during the test in step 7, is compared and analyzed. Combined with the thermal fatigue cycle resistance of the test blades determined by the inspection and analysis during the test in step 7, the thermal fatigue cycle resistance of the air-cooled turbine guide vane is finally determined.

9. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 8, characterized in that: In step 9, the temperature load spectrum determined in step 4 is input into the simulation calculation model for calculation, and its peak temperature T is obtained respectively. test,max Valley temperature T test,min The corresponding distributions of the first principal stress, first principal strain, and third principal strain, where the peak temperature T at the test point of the test section is... test,max The first principal stress and the first principal strain calculated under the working condition are denoted as σ1. max ε1 max The valley temperature T at the test section test point test,min The corresponding first principal stress, first principal strain, and third principal strain are denoted as σ1. min ε1 min ε3 min Under valley temperature conditions, the condition may primarily manifest as a compressive state, requiring the first principal strain ε1 under peak temperature conditions to be considered. max Comparing the directions of the first and third principal strains under the valley temperature condition, the principal strain whose direction is the same as or opposite to that of the first principal strain under the peak temperature condition is selected as the principal strain under the valley temperature condition, denoted as: e min =[ε1 max ,(ε1 min 、e3 min )] (2) Its principal strain range is: No 主 =ε1 max -e min (3) Substituting this into the following formula, we obtain the number of cycles, i.e., the thermal fatigue cycle resistance N of the high-pressure turbine guide vane. f : In the formula, b is the fatigue strength index, c is the fatigue ductility index, and σ f ε is the fatigue strength coefficient. f Where E is the fatigue ductility coefficient, E is the elastic modulus, and N is the fatigue ductility coefficient. f For resistance to thermal fatigue cycles.

10. The accelerated thermal shock test method for air-cooled turbine guide vanes of a gas-driven compressor unit as described in claim 9, characterized in that: In step 10, the thermal fatigue cycle resistance N calculated in step 9 is used. f N obtained from the experiment in step 8 test In comparison, if N f / N test ≥5, then N test This refers to the thermal fatigue cycle resistance of the high-pressure turbine guide vanes; if N f / N test If the result is less than 5, the test plan needs to be readjusted and the test conducted.

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