Flame tube thermal shock test device with cooling outflow function and test method

Abstract

The invention discloses a flame tube thermal shock test device and method with cooling outflow, and the device comprises a test system which comprises a test bench, a flame gun and a sample clamp, the flame gun and the sample clamp are correspondingly arranged on the test bench, a thermal barrier coating test piece is clamped and positioned by the sample clamp, and small hole structures are distributed on the thermal barrier coating test piece; the cooling system is used for supplying cooling air flow to the thermal barrier coating test piece, so that the cooling air flow is input from the low-temperature side of the thermal barrier coating test piece and forms a cooling air film on the high-temperature side after flowing through the small hole structure, a temperature gradient is formed in the thickness direction of the thermal barrier coating test piece, and a temperature gradient is formed on the high-temperature side of the thermal barrier coating test piece in the cooling air flow direction; and the control system is used for regulating and controlling the temperatures of the low-temperature side and the high-temperature side of the thermal barrier coating test piece. The temperature distribution of the wall surface of the real flame tube can be realized, and the device has the advantages of accurate and adjustable temperature gradient of the thermal barrier coating test piece, simple operation, low cost and the like.

Description

Technical Field

[0001] The present invention relates to the field of aviation engines, and in particular to a flame tube thermal shock test device with a cooling outflow and a test method. Background Art

[0002] As aircraft engines develop towards high temperature rise and high thrust-to-weight ratio, the flame tube, as the hot end component of the engine, faces increasingly harsh working environments, and the flame tube life is directly related to the service life of the aircraft engine. Prolonged exposure to high temperatures will cause creep deformation of the flame tube. Due to the complexity of the flow field within the flame tube, there is a large temperature gradient on the flame tube wall, which is also one of the reasons for the generation of thermal stress. When the engine switches operating states, the flame tube must also withstand alternating thermal stress. In addition, the flame tube has a complex structure, with many air inlet holes on the tube wall. The hole structure will also cause a large temperature gradient on the flame tube wall. The thermal stress on the flame tube is the main factor affecting the flame tube life. Therefore, applying a temperature distribution that matches the actual temperature distribution of the combustion chamber wall when conducting a thermal shock test on the flame tube wall is a key factor in achieving flame tube life prediction.

[0003] The existing technology for evaluating the life of the flame tube is complex and costly, and does not actually consider the temperature distribution of the flame tube wall and the impact of alternating stress on the flame tube life when switching between different working states. Summary of the Invention

[0004] In view of this, the present invention provides a flame tube thermal shock test device and test method with cooling outflow to solve the problem that the current flame tube life assessment method does not actually consider the impact of the temperature distribution of the flame tube wall on the flame tube life.

[0005] In a first aspect, the present invention provides a flame tube thermal shock test device with a cooling outflow, comprising:

[0006] A test system, the test system comprising a test bench, a flame spray gun, and a sample fixture, the flame spray gun and the sample fixture being respectively disposed on the test bench, the sample fixture clamping and positioning a thermal barrier coating test piece, the side of the thermal barrier coating test piece facing the flame spray gun being a high-temperature side, the side of the thermal barrier coating test piece facing away from the flame spray gun being a low-temperature side, and the thermal barrier coating test piece being distributed with a small hole structure having the characteristics of a flame tube wall;

[0007] A cooling system for supplying a cooling airflow to the thermal barrier coating specimen, so that the cooling airflow is input from the low-temperature side of the thermal barrier coating specimen and flows through the small hole structure to form a cooling air film on the high-temperature side, thereby forming a temperature gradient in the thickness direction of the thermal barrier coating specimen and forming a temperature gradient along the cooling airflow direction on the high-temperature side of the thermal barrier coating specimen;

[0008] A control system is used to control the cooling system and / or the flame spray gun to regulate the temperature of the low-temperature side and the high-temperature side of the thermal barrier coating specimen.

[0009] The beneficial effects of the aforementioned flame tube thermal shock test apparatus with cooling outflow are as follows: The present invention simulates the characteristics of the flame tube wall by using the small holes in the thermal barrier coating specimen. In conjunction with the cooling system, cooling airflow is fed to the low-temperature side, allowing the airflow to flow through the small holes and form a cooling air film on the high-temperature side. This allows for the simultaneous formation of temperature gradients consistent with actual operating conditions, both along the thickness of the thermal barrier coating specimen and along the cooling airflow direction on the high-temperature side. This restores the true temperature distribution of the flame tube caused by its complex flow field and open hole structure, resolving the issue of prior art failing to consider actual temperature distribution. This allows the thermal shock test to more closely resemble the actual operating conditions of the flame tube, thereby improving the reliability of life prediction. The control system regulates the operating conditions of the cooling system and flame spray gun, simulating the alternating thermal stresses experienced by the flame tube when the engine switches operating modes. This addresses the prior art's failure to consider the impact of alternating stress on life, enabling the test to more comprehensively reflect the actual damage mechanisms of the flame tube.

[0010] The present invention realizes the integrated control of temperature gradient, cooling air film and alternating stress by integrating the test system, cooling system and control system, avoiding the complex operation of multiple equipment and multiple steps in traditional methods, and reducing the test cost and operation difficulty.

[0011] In an optional embodiment, a tongue channel and a connecting channel are provided inside the sample fixture, the connecting channel is connected to the cooling system, the tongue channel is connected to the connecting channel, and the outlet of the tongue channel is arranged on the low temperature side of the thermal barrier coating specimen.

[0012] In an optional embodiment, the outlet of the tongue channel is arranged upward so that the cooling airflow output from the outlet of the tongue channel is transmitted upward along the low-temperature side of the thermal barrier coating test piece;

[0013] The small hole structure is arranged obliquely upward from the low-temperature side to the high-temperature side, so that the transmission direction of the cooling air film formed on the high-temperature side of the thermal barrier coating test piece is upward.

[0014] In an optional embodiment, a plurality of first thermocouples are provided on the side of the thermal barrier coating specimen facing away from the flame spray gun, and the first thermocouples are used to detect the temperature distribution condition of the low-temperature side of the thermal barrier coating specimen;

[0015] A plurality of second thermocouples are arranged at intervals along the cooling airflow direction on the side of the thermal barrier coating test piece facing the flame spray gun, and the second thermocouples are used to detect the temperature distribution condition of the high-temperature side of the thermal barrier coating test piece;

[0016] The control system includes a thermocouple temperature feedback module, and the output ends of the first thermocouple and the second thermocouple are respectively connected to the input end of the thermocouple temperature feedback module.

[0017] In an optional embodiment, the flame spray gun is connected to a gas tank via a gas pipeline, and a gas flow meter is provided on the gas pipeline for controlling the flow of gas input to the flame spray gun; the flame spray gun is also connected to an oxygen tank via an oxygen pipeline, and an oxygen flow meter is provided on the oxygen pipeline for controlling the flow of oxygen input to the flame spray gun;

[0018] The control system further includes a gas flow control module and an oxygen flow control module, wherein a controlled end of the gas flow meter is connected to an output end of the gas flow control module, and a controlled end of the oxygen flow meter is connected to an output end of the oxygen flow control module. Before a cooling airflow is introduced into the thermal barrier coating test piece, the flame spray gun sprays high-temperature gas toward the thermal barrier coating test piece. The thermocouple temperature feedback module receives temperature detection information from the second thermocouple and compares it with set temperature information, thereby controlling the gas flow meter through the gas flow control module and controlling the oxygen flow meter through the oxygen flow control module to control the amount of high-temperature gas sprayed from the flame spray gun.

[0019] In an optional embodiment, the cooling system includes a cooling air supply device, which includes a cooling air supply box, an air supply pipe, a heater, and a flow valve. The cooling air supply box is connected to the air supply pipe, and the heater and the flow valve are both arranged on the air supply pipe inside the cooling air supply box.

[0020] The control system includes a cooling airflow control module, which includes a temperature control module and a flow control module. The controlled end of the heater is connected to the output end of the temperature control module, and the controlled end of the flow valve is connected to the output end of the flow control module.

[0021] After the cooling airflow is introduced into the thermal barrier coating test piece, the thermocouple temperature feedback module receives the temperature detection information of the first thermocouple and compares it with the set temperature information, and then controls the heater through the temperature control module to control the temperature of the cooling airflow, and controls the flow valve through the flow control module to control the flow of the cooling airflow.

[0022] In an optional embodiment, the cooling system further includes a flame spray gun water cooling device, the flame spray gun water cooling device including a cooling water tank and a water cooling pipe, one end of the water cooling pipe is connected to the cooling water tank, and the other end of the water cooling pipe is connected to the water cooling pipe of the flame spray gun head, and a flow valve is provided on the water cooling pipe;

[0023] The control system further includes a water cooling control module, and the controlled end of the flow valve is connected to the output end of the water cooling control module.

[0024] In an optional embodiment, the flame spray gun head is provided with an igniter for ignition, and the control system further comprises an ignition module, and the igniter ignites the combustible mixture sprayed from the flame spray gun under the control of the ignition module.

[0025] In a second aspect, the present invention provides a method for thermal shock testing a flame tube with a cooling outflow, comprising the following steps:

[0026] S1. Ignite the flame spray gun and spray out high-temperature gas;

[0027] S2. The side of the thermal barrier coating specimen facing the flame spray gun is heated to a first preset temperature;

[0028] S3. Maintaining the flame spray gun fuel flow rate unchanged, continuing to generate high-temperature combustion gas, ensuring that the high-temperature side of the thermal barrier coating specimen is maintained at a first preset temperature; passing a cooling airflow through the low-temperature side of the thermal barrier coating specimen to cool it to a second preset temperature, thereby forming a temperature gradient in the thickness direction of the thermal barrier coating specimen, and forming a temperature gradient along the airflow direction on the high-temperature side of the thermal barrier coating specimen due to the action of the small pore structure;

[0029] S4. Ensure that the gas temperature and cooling air flow temperature remain unchanged and maintain this state for a period of time;

[0030] S5. Control the temperature on both sides of the thermal barrier coating specimen so that the thermal barrier coating specimen changes from the operating temperature of condition A to the operating temperature of condition B, and then changes from the operating temperature of condition B back to the operating temperature of condition A;

[0031] S6. Repeat step S5. When the cracks on the thermal barrier coating specimen reach a preset size or the coating peels off, stop the test and record the number of cycles.

[0032] In an optional embodiment, the following steps are further included: according to the actual operating conditions of the combustion chamber, the temperature change pattern on the gas side and the cold air side of the flame tube is obtained from the temperature cycle spectrum, and a simulation test is carried out according to this pattern; after the thermal barrier coating specimen reaches the operating condition A temperature, it is maintained for a period of time, and then the temperature on both sides of the thermal barrier coating specimen is adjusted according to the cycle spectrum; if the operating condition B temperature level is higher than the operating condition A temperature, the temperature is continued to be increased until the temperature on both sides of the thermal barrier coating specimen reaches the specified temperature value; if the operating condition B temperature level is lower than the operating condition A temperature, the temperature of the high-temperature gas ejected from the flame spray gun is reduced by controlling the amount of oil supply, and / or the heater is adjusted to reduce the temperature of the cooling air flow, so as to reduce the temperature on both sides of the thermal barrier coating specimen.

[0033] In summary, the technical solution of the present invention has the following advantages:

[0034] The present invention can realize the temperature distribution of the wall surface of a real flame tube. While realizing the existence of temperature gradients in the thickness direction of the thermal barrier coating specimen and along the direction of the cooling airflow, it also takes into account the influence of the combined effect of alternating stresses caused by switching working states on the life of the flame tube. The present invention has the advantages of precise adjustment of the temperature gradient of the thermal barrier coating specimen, simple operation, and low cost. In addition, the presence of small hole structures on the thermal barrier coating specimen will cause a large temperature gradient to be generated at the hole edge, resulting in excessive thermal stress. The present invention takes into account the influence of the thermal stress at the hole edge on the life of the flame tube.

[0035] The temperature on both sides of the thermal barrier coating test piece of the present invention is precisely adjustable. By adjusting the flow rates of fuel gas and oxygen, the temperature of the side of the thermal barrier coating test piece facing the flame spray gun can be precisely controlled. The cooling temperature value is given by the control system, and the thermocouple monitors the temperature of the side of the coating test piece facing away from the flame spray gun, thereby achieving precise control of the cooling temperature.

[0036] The present invention has a cooling air channel formed by tongues inside the sample fixture. In order to obtain a corresponding temperature gradient in the thickness direction of the thermal barrier coating specimen, it is necessary to introduce a cooling airflow on the side of the thermal barrier coating specimen facing away from the flame spray gun. Therefore, a guide channel formed by tongues is provided in the sample fixture, so that the cooling airflow transported through the pipeline flows through the plane of the thermal barrier coating specimen on the side facing away from the flame spray gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A schematic structural diagram of a flame tube thermal shock test device with cooling outflow provided by the present invention;

[0039] Figure 2 A schematic diagram of various modules in a control system of a flame tube thermal shock test device with cooling outflow provided by the present invention;

[0040] Figure 3 Schematic diagram of low-temperature side cooling airflow for a thermal barrier coating test piece of a flame tube thermal shock test apparatus with cooling outflow provided by the present invention;

[0041] Figure 4 The present invention provides a flow chart of a thermal shock test method for a flame tube with cooling outflow.

[0042] Description of reference numerals:

[0043] 11. Test bench; 12. Flame spray gun; 13. Sample fixture; 131. Tongue channel; 14. Thermal barrier coating specimen; 141. Small hole structure; 15. First thermocouple; 16. Second thermocouple; 17. Gas tank; 18. Oxygen tank; 19. Gas flow meter; 20. Oxygen flow meter; 21. Ignitor; 22. Gas supply pipeline; 31. Cooling air flow control module; 311. Temperature control module; 312. Flow control module; 32. Ignition module; 33. Gas flow control module; 34. Oxygen flow control module; 35. Water cooling control module; 36. Thermocouple temperature feedback module; 41. Cooling air flow supply device; 411. Heater; 412. Flow valve; 42. Cooling water tank; 421. Water cooling pipeline. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0045] As aircraft engines develop towards high temperature rise and high thrust-to-weight ratio, the flame tube, as the hot end component of the engine, faces increasingly harsh working environments, and the flame tube life is directly related to the service life of the aircraft engine. Prolonged exposure to high temperatures will cause creep deformation of the flame tube. Due to the complexity of the flow field within the flame tube, there is a large temperature gradient on the flame tube wall, which is also one of the reasons for the generation of thermal stress. When the engine switches operating states, the flame tube must also withstand alternating thermal stress. In addition, the flame tube has a complex structure, with many air inlet holes on the tube wall. The hole structure will also cause a large temperature gradient on the flame tube wall. The thermal stress on the flame tube is the main factor affecting the flame tube life. Therefore, applying a temperature distribution that matches the actual temperature distribution of the combustion chamber wall when conducting a thermal shock test on the flame tube wall is a key factor in achieving flame tube life prediction.

[0046] The existing flame tube life assessment methods are mainly the following:

[0047] 1) A Chinese invention patent with authorization publication number CN114047089B proposes a method for calculating the life of materials under thermal shock loads. By considering factors such as the severity of the thermal shock, the driving force that causes fatigue cracks to further expand during the thermal shock process, and material properties during the thermal shock test, a thermal shock life calculation model is constructed. This model illustrates the functional relationship between thermal fatigue cracks and thermal shock temperature, and between the number of cycles and material life. The patent establishes a functional relationship between thermal fatigue crack length and stress intensity factor, and characterizes the severity of the thermal shock by introducing the temperature change rate of the material during the thermal shock process. It considers the impact of various test conditions on the material life during the thermal shock process, but only studies the life prediction under a single temperature condition and does not consider the alternating stress generated when the flame tube switches between different operating conditions.

[0048] 2) Chinese invention patent publication number CN116429436A conducts thermal shock testing on combustion chamber components. By introducing primary gas into the flame tube to achieve uniform heating of the flame tube, and then using percussion gas to heat a pre-set area on the flame tube, the test simulates the temperature gradient of the flame tube wall under specified conditions. This patent uses the entire combustion chamber component for flame tube life assessment, resulting in a complex and costly structure. By using primary and percussion gas to control the flame tube wall temperature and studying the temperature gradient along the axial wall, the patent fails to consider the significant thermal stresses present in the small holes on the flame tube wall.

[0049] 3) The Chinese invention patent with publication number CN114964800A proposes a test method for testing the thermal fatigue performance of a flame tube. By automatically controlling the fuel flow rate, the fuel flow rate is increased from the flow value in the low temperature state to the flow value in the high temperature state, and then decreased from the flow value in the high temperature state to the flow value in the low temperature state, thereby completing the flame tube thermal fatigue performance test. This patent obtains the required flame tube operating temperature through automatic control of the fuel flow rate, realizes the high and low cycle of the flame tube operating temperature, and completes the flame tube thermal fatigue test process. Although the alternating stress of the flame tube when switching the working state is taken into account, there is no cooling airflow module. In the actual flame tube, there are pore structures such as divergent holes. The cold air on the outer wall will have a cooling effect on the flame tube wall surface, and a temperature gradient will be generated in the thickness direction of the flame tube wall and the cooling airflow velocity direction.

[0050] Existing methods for evaluating flame liner life are complex and costly, and fail to consider the temperature distribution of the liner wall and the impact of alternating stresses on liner life when switching between different operating states. Therefore, the present invention provides a flame liner thermal shock test method and apparatus that considers the actual liner wall temperature distribution, ensures the liner's true wall structure, and is simple to operate and low-cost.

[0051] The present invention regulates the temperature on both sides of a thermal barrier coating (TBC) specimen to obtain temperature gradients in different directions. A control system loads the temperature on both sides of the TBC specimen in a time-domain manner, causing the temperature to reach a preset operating condition. This allows the failure of the TBC coating on the TBC specimen surface to be determined, thereby predicting the life of the flame tube. The TBC specimen facing the flame spray gun is the high-temperature side, while the side facing away from the flame spray gun is the low-temperature side. The high-temperature side of the TBC specimen is heated by high-temperature fuel gas ejected from the flame spray gun. The temperature of the high-temperature side of the TBC specimen is regulated by adjusting the flow rates of fuel and oxygen. This allows for a wide range of heating temperatures at a low cost, is simple to operate, and test equipment is readily available. The low-temperature side of the TBC specimen, on the other hand, uses a control system to send instructions to a cooling air supply device, which outputs cooling air with adjustable temperature and flow parameters, accurately simulating the cold air environment on the flame tube wall during actual operation. When cooling air is introduced into the low-temperature side of the TBC specimen, it flows through small holes in the TBC specimen, forming a cooling air film on the high-temperature side of the TBC specimen. On the one hand, a temperature gradient forms across the thickness of the thermal barrier coating specimen. On the other hand, under the influence of the cooling air film, the wall temperature on the high-temperature side of the thermal barrier coating specimen gradually decreases along the direction of the cooling airflow, creating a temperature gradient and generating significant thermal stress. By changing the operating state based on this, the effects of alternating stresses on the flame tube life can be simultaneously studied. This thermal shock test method considers the actual thermal stress loading on the combustion chamber wall and the combined effects of various thermal stresses. It also retains the divergent small holes on the flame tube body, where large temperature gradients exist around the holes, generating significant thermal stresses. This method is more consistent with the actual operating conditions of the flame tube. Simulating the high-temperature service environment of the thermal barrier coating specimen under more realistic conditions is of great significance for evaluating the flame tube's service life.

[0052] According to an embodiment of the present invention, in the first aspect, a flame tube thermal shock test device with a cooling outflow is provided, Figures 1 to 3 As shown, it includes test system, cooling system and control system.

[0053] The test system includes a test bench 11, a flame spray gun 12, and a specimen fixture 13. The flame spray gun 12 and specimen fixture 13 are respectively mounted on the test bench 11. The specimen fixture 13 is used to clamp and position a thermal barrier coating specimen 14. The side of the thermal barrier coating specimen 14 facing the flame spray gun 12 is the high-temperature side, and the side of the thermal barrier coating specimen 14 facing away from the flame spray gun 12 is the low-temperature side. The thermal barrier coating specimen 14 is distributed with a small hole structure 141 that has the characteristics of the flame tube wall. The small hole structure on the thermal barrier coating specimen 14 has the characteristics of the wall surface of a real combustion chamber. A real flame tube is an open-hole thin-walled structure with many diverging holes of different apertures. Therefore, the use of a thermal barrier coating specimen with holes takes into account the realistic flame tube structure.

[0054] The cooling system is used to supply cooling air to the thermal barrier coating specimen 14. The cooling airflow is introduced from the low-temperature side of the thermal barrier coating specimen 14 and flows through the small hole structure 141, forming a cooling air film on the high-temperature side. This creates a temperature gradient across the thickness of the thermal barrier coating specimen 14 (between the high-temperature and low-temperature sides), and also forms a temperature gradient along the direction of the cooling airflow on the high-temperature side of the thermal barrier coating specimen 14. Film cooling occurs on the specimen wall. When cooling airflow is introduced to the low-temperature side of the specimen, it flows through the small holes, forming a cooling air film on the high-temperature side. The specimen wall temperature decreases continuously along the direction of the cooling airflow, resulting in a large temperature gradient.

[0055] The control system is used to control the cooling system and / or the flame spray gun 12 to regulate the temperature of the low-temperature side and the high-temperature side of the thermal barrier coating specimen 14 .

[0056] The aforementioned flame tube thermal shock test apparatus with cooling outflow simulates the characteristics of the flame tube wall through the small holes in the thermal barrier coating specimen 14. The cooling system then delivers cooling airflow to the low-temperature side, allowing the airflow to flow through the holes and form a cooling air film on the high-temperature side. This design simultaneously creates temperature gradients consistent with actual operating conditions, both along the thickness of the thermal barrier coating specimen 14 and along the cooling airflow direction on the high-temperature side. This replicates the true temperature distribution of the flame tube caused by its complex flow field and open hole structure, resolving the issue of existing technologies that fail to account for actual temperature distribution. This allows thermal shock testing to more closely resemble the actual operating conditions of the flame tube, thereby improving the reliability of life predictions.

[0057] The control system can regulate the working status of the cooling system and the flame spray gun, simulating the alternating thermal stress that the flame tube is subjected to when the engine switches working states. This makes up for the defect that the existing technology does not consider the impact of alternating stress on life, and enables the test to more comprehensively reflect the actual damage mechanism of the flame tube.

[0058] The present invention realizes the integrated control of temperature gradient, cooling air film and alternating stress by integrating the test system (test bench, flame spray gun, sample fixture), cooling system and control system, avoiding the complex operation of multiple equipment and multiple steps in traditional methods, and reducing test costs and operational difficulty.

[0059] In some embodiments, a tongue channel 131 and a connecting channel are provided inside the sample fixture 13. The connecting channel is connected to the cooling system. The tongue channel 131 is connected to the connecting channel. The outlet of the tongue channel 131 is arranged on the low-temperature side of the thermal barrier coating specimen 14. The tongue channel 131 can accurately guide the airflow supplied by the cooling system to the low-temperature side surface of the thermal barrier coating specimen, avoiding airflow dispersion or path deviation, ensuring that the cooling airflow can flow through the specimen surface in a preset direction, forming a temperature gradient in the thickness direction of the specimen that is closer to the actual working conditions of the flame tube, and improving the degree of restoration of the test to the real working environment.

[0060] When the cooling system cools the thermal barrier coating specimen 14, the cooling airflow enters the internal communication channel of the specimen fixture 13 through the air supply pipe 22, and then flows into the tongue channel 131 built into the specimen fixture 13. The outlet of the tongue channel 131 is arranged on the side of the specimen away from the flame spray gun, so that the cooling airflow flows through the surface of the thermal barrier coating specimen 14, cooling the surface of the thermal barrier coating specimen 14 away from the flame spray gun.

[0061] In some embodiments, the outlet of the tongue channel 131 is positioned upward, allowing the cooling airflow output from the outlet of the tongue channel 131 to be transmitted upward along the low-temperature side of the thermal barrier coating specimen 14, simulating the actual airflow path on the low-temperature side of the flame tube wall. The small hole structure 141 is arranged upward, tilted from the low-temperature side to the high-temperature side, so that the cooling air film formed on the high-temperature side of the thermal barrier coating specimen 14 is transmitted upward, consistent with the flow direction of the cooling air film on the high-temperature side of the flame tube in actual operation. In this embodiment, the temperature gradient distribution on the specimen surface is perfectly matched to the actual operating conditions of the flame tube, resolving the temperature gradient distortion problem caused by deviation in airflow direction simulation in the prior art and significantly improving the accuracy of life prediction.

[0062] In some embodiments, a plurality of first thermocouples 15 are disposed on the side of the thermal barrier coating specimen 14 facing away from the flame spray gun 12. These first thermocouples 15 are used to detect the temperature distribution on the low-temperature side of the thermal barrier coating specimen 14. A plurality of second thermocouples 16 are disposed at intervals along the cooling airflow direction on the side of the thermal barrier coating specimen 14 facing the flame spray gun 12. These second thermocouples 16 are used to detect the temperature distribution on the high-temperature side of the thermal barrier coating specimen 14. The control system includes a thermocouple temperature feedback module 36. The outputs of the first and second thermocouples 15, 16 are respectively connected to the inputs of the thermocouple temperature feedback module 36.

[0063] In some embodiments, a gas nozzle for generating high-temperature fuel gas is disposed within the flame spray gun 12. The gas nozzle of the flame spray gun 12 is connected to a gas tank 17 via a gas pipeline. The gas nozzle of the flame spray gun 12 is also connected to an oxygen tank 18 via an oxygen pipeline, enabling the flame spray gun 12 to heat the thermal barrier coating specimen 14. A gas flowmeter 19 is provided on the gas pipeline to control the flow of fuel gas input to the flame spray gun. An oxygen flowmeter 20 is provided on the oxygen pipeline to control the flow of oxygen input to the flame spray gun.

[0064] The control system further includes a gas flow control module 33 and an oxygen flow control module 34 . The controlled end of the gas flow meter 19 is connected to the output end of the gas flow control module 33 , and the controlled end of the oxygen flow meter 20 is connected to the output end of the oxygen flow control module 34 .

[0065] Before the cooling airflow is introduced into the thermal barrier coating test piece 14, the flame spray gun 12 sprays high-temperature fuel gas toward the thermal barrier coating test piece 14. The thermocouple temperature feedback module 36 receives the temperature detection information of the first thermocouple 15 and the second thermocouple 16, and compares the temperature signal feedback obtained by monitoring with the set temperature information. Then, the gas flow control module 33 controls the gas flow meter 19, and the oxygen flow control module 34 controls the oxygen flow meter 20, thereby controlling the gas flow rate and oxygen flow rate to control the amount of high-temperature fuel gas sprayed by the flame spray gun 12, thereby achieving precise control of the wall temperature on both sides of the test piece.

[0066] In some embodiments, the cooling system includes a cooling air supply device 41, which includes a cooling air supply box, an air supply pipe 22, a heater 411, and a flow valve 412. The cooling air supply box is connected to the air supply pipe 22, and the other end of the air supply pipe 22 is connected to a communication channel provided in the specimen holder 13. The heater 411 and the flow valve 412 are both provided on the air supply pipe 22 within the cooling air supply box. The controlled ends of the heater 411 and the flow valve 412 are respectively connected to the output end of the control system.

[0067] The control system includes a cooling airflow control module 31. This module sends instructions to a cooling airflow supply device 41 to generate cooling airflow with specified parameters, such as the amount of cooling air used to cool the working medium and the temperature of the cooling airflow, under different operating conditions. The cooling airflow control module 31 includes a temperature control module 311 and a flow control module 312. The controlled end of a heater 411 is connected to the output of the temperature control module 311, and the controlled end of a flow valve 412 is connected to the output of the flow control module 312. Under the control of the cooling airflow control module 31, air is first delivered to the heater 411 and heated to a preset temperature. The air is then connected to the flow valve 412 to control the cooling air flow.

[0068] After cooling air is introduced into the thermal barrier coating test piece 14, the thermocouple temperature feedback module 36 receives the temperature information detected by the first thermocouple 15 and the second thermocouple 16 and compares it with the set temperature information. The module then controls the heater 411 via the temperature control module 311 to control the temperature of the cooling airflow, and controls the flow valve 412 via the flow control module 312 to control the flow of the cooling airflow, thereby achieving precise control of the wall temperature on both sides of the test piece. For example, when the temperature information detected by the first thermocouple 15 and the second thermocouple 16 is lower than the set temperature, it indicates that the flow rate of the incoming cooling airflow is large or the temperature of the cooling airflow is low. In this case, the heater 411 is adjusted to increase the cooling air temperature and / or the opening of the flow valve 412 is reduced. Conversely, when the temperature information detected by the first thermocouple 15 and the second thermocouple 16 is higher than the set temperature, it indicates that the flow rate of the incoming cooling airflow is small or the temperature of the cooling airflow is high. In this case, the heater 411 is adjusted to reduce the cooling air temperature and / or the opening of the flow valve 412 is increased.

[0069] In some embodiments, the cooling system further includes a flame spray gun water cooling device, which includes a cooling water tank 42 and a water cooling pipe 421. One end of the water cooling pipe 421 is connected to the cooling water tank 42, and the other end of the water cooling pipe 421 is connected to the water cooling pipe at the head of the flame spray gun 12. A flow valve is provided on the water cooling pipe 421. Under the control of the flow valve by the water cooling control module 35, the cooling water in the cooling water tank 42 flows into the water cooling pipe arranged inside the flame spray gun, thereby cooling the flame spray gun.

[0070] The control system also includes a water cooling control module 35. The controlled end of the flow valve is connected to the output end of the water cooling control module 35. The water cooling control module 35 can then control the opening of the flow valve, control the amount of cooling water supplied to the flame spray gun, and achieve temperature regulation of the high-temperature fuel gas ejected by the flame spray gun.

[0071] In some embodiments, an igniter 21 for ignition is arranged at the head of the flame spray gun 12 , and the control system further includes an ignition module 32 . The igniter 21 ignites the combustible mixture sprayed from the flame spray gun 12 under the control of the ignition module 32 .

[0072] According to an embodiment of the present invention, in a second aspect, a method for thermal shock testing a flame tube with a cooling outflow is provided. According to the actual operating conditions of the combustion chamber, the temperature variation pattern of the gas side and the cold air side of the flame tube is obtained from the temperature cycle spectrum, and a simulation test is performed according to this pattern. For example: after the thermal barrier coating test piece 14 reaches the operating condition A temperature, it is maintained for a period of time, and then the temperature on both sides of the thermal barrier coating test piece 14 is adjusted according to the cycle spectrum. If the operating condition B temperature level is higher than the operating condition A temperature, the temperature is continued to rise until the temperature on both sides of the thermal barrier coating test piece 14 reaches the specified temperature value. If the operating condition B temperature level is lower than the operating condition A temperature, the temperature of the high-temperature gas ejected from the flame spray gun 12 is reduced by controlling the amount of oil supply, and / or the heater 411 is adjusted to reduce the temperature of the cooling air flow, thereby reducing the temperature on both sides of the thermal barrier coating test piece 14.

[0073] It should be noted that when switching from one operating temperature to another, it is necessary to maintain the operating temperature after the switch for a period of time.

[0074] A thermal shock test method for a flame tube with cooling outflow, combined with Figure 4 As shown, the following steps are included:

[0075] S1. The flame spray gun 12 is ignited and high-temperature combustion gas is ejected.

[0076] S2. The side of the thermal barrier coating test piece 14 facing the flame spray gun 12 is heated to a first preset temperature. High-temperature fuel gas is sprayed from the flame spray gun 12. Multiple second thermocouples 16 are welded to the side of the test piece facing the flame spray gun to determine whether the test piece temperature meets the preset operating conditions. If the second thermocouples detect a low test piece temperature, the flame spray gun fuel injection rate is increased, and the temperature is continued to rise until the test piece temperature reaches the desired set point.

[0077] S3. Maintain a constant fuel flow rate in the flame spray gun 12 and continue to generate high-temperature combustion gas to ensure that the high-temperature side of the thermal barrier coating test piece 14 is maintained at a first preset temperature. A cooling airflow is passed through the low-temperature side of the thermal barrier coating test piece 14, cooling it to a second preset temperature. This creates a temperature gradient across the thickness of the thermal barrier coating test piece 14, and, due to the action of the small pore structure 141, a temperature gradient is formed along the airflow direction on the high-temperature side of the thermal barrier coating test piece 14. While the cooling airflow is flowing, multiple first thermocouples 15 welded to the side of the test piece facing the cooling airflow determine whether the temperature of the test piece on the side facing the cooling airflow meets the preset operating conditions. If the first thermocouples detect that the temperature of the test piece on that side is too low, the temperature control module 311 in the cooling airflow control module 31 is increased, causing the heater 411 to heat the air until the temperature of the test piece on that side reaches the desired temperature. The thermocouple temperature feedback module 36 controls the fuel gas flow rate, oxygen flow rate, cooling air temperature, and cooling air flow rate based on the monitored temperature signals, achieving precise control of the wall temperatures on both sides of the test piece.

[0078] S4. Ensure that the gas temperature and cooling air flow temperature remain unchanged and maintain this state for a period of time.

[0079] S5. Control the temperature on both sides of the thermal barrier coating test piece 14 so that the thermal barrier coating test piece changes from the operating temperature of condition A to the operating temperature of condition B, and then changes from the operating temperature of condition B back to the operating temperature of condition A.

[0080] S6. Repeat step S5. When the cracks on the thermal barrier coating specimen 14 reach a preset size or the coating peels off, stop the test and record the number of cycles.

[0081] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. Flame tube thermal shock test device with cooling outflow, characterized in that: include: A test system, the test system comprising a test bench (11), a flame spray gun (12) and a sample fixture (13), wherein the flame spray gun (12) and the sample fixture (13) are respectively arranged on the test bench (11), the sample fixture (13) clamps and positions a thermal barrier coating test piece (14), the side of the thermal barrier coating test piece (14) facing the flame spray gun (12) is a high-temperature side, and the side of the thermal barrier coating test piece (14) facing away from the flame spray gun (12) is a low-temperature side, and the thermal barrier coating test piece (14) is distributed with a small hole structure (141) having the characteristics of a flame tube wall; A cooling system is provided for supplying a cooling airflow to the thermal barrier coating test piece (14), so that the cooling airflow is input from the low-temperature side of the thermal barrier coating test piece (14) and flows through the small hole structure (141) to form a cooling air film on the high-temperature side, thereby forming a temperature gradient in the thickness direction of the thermal barrier coating test piece (14), and forming a temperature gradient along the cooling airflow direction on the high-temperature side of the thermal barrier coating test piece (14); A control system is provided, wherein the control system is used to control a cooling system and / or a flame spray gun (12) to regulate the temperature of a low-temperature side and a high-temperature side of a thermal barrier coating test piece (14).

2. The flame tube thermal shock test device with cooling outflow according to claim 1, characterized in that: The sample fixture (13) is provided with a tongue channel (131) and a communication channel inside, the communication channel is connected to the cooling system, the tongue channel (131) is connected to the communication channel, and the outlet of the tongue channel (131) is arranged on the low-temperature side of the thermal barrier coating test piece (14).

3. The flame tube thermal shock test device with cooling outflow according to claim 2, characterized in that: The outlet of the tongue channel (131) is arranged upward so that the cooling airflow output from the outlet of the tongue channel (131) is transmitted upward along the low-temperature side of the thermal barrier coating test piece (14); The small hole structure (141) is arranged obliquely upward from the low-temperature side to the high-temperature side, so that the transmission direction of the cooling air film formed on the high-temperature side of the thermal barrier coating test piece (14) is upward.

4. The flame tube thermal shock test device with cooling outflow according to any one of claims 1 to 3, characterized in that: A plurality of first thermocouples (15) are provided on a side of the thermal barrier coating test piece (14) facing away from the flame spray gun (12), wherein the first thermocouples (15) are used to detect the temperature distribution condition on the low-temperature side of the thermal barrier coating test piece (14); A plurality of second thermocouples (16) are arranged at intervals along the cooling airflow direction on a side of the thermal barrier coating test piece (14) facing the flame spray gun (12), and the second thermocouples (16) are used to detect the temperature distribution condition of the high-temperature side of the thermal barrier coating test piece (14); The control system comprises a thermocouple temperature feedback module (36), and the output ends of the first thermocouple (15) and the second thermocouple (16) are respectively connected to the input end of the thermocouple temperature feedback module (36).

5. The flame tube thermal shock test device with cooling outflow according to claim 4, characterized in that: The flame spray gun (12) is connected to a gas tank (17) via a gas pipeline, and a gas flow meter (19) is provided on the gas pipeline for controlling the flow of gas input to the flame spray gun; the flame spray gun (12) is also connected to an oxygen tank (18) via an oxygen pipeline, and an oxygen flow meter (20) is provided on the oxygen pipeline for controlling the flow of oxygen input to the flame spray gun; The control system further comprises a gas flow control module (33) and an oxygen flow control module (34); the controlled end of the gas flow meter (19) is connected to the output end of the gas flow control module (33), and the controlled end of the oxygen flow meter (20) is connected to the output end of the oxygen flow control module (34); before the cooling air flow is introduced into the thermal barrier coating test piece (14), the flame spray gun (12) sprays high-temperature gas toward the thermal barrier coating test piece (14); the thermocouple temperature feedback module (36) receives the temperature detection information of the second thermocouple (16) and compares it with the set temperature information, and then controls the gas flow meter (19) through the gas flow control module (33) and controls the oxygen flow meter (20) through the oxygen flow control module (34), so as to control the amount of high-temperature gas sprayed by the flame spray gun (12).

6. The flame tube thermal shock test device with cooling outflow according to claim 4, characterized in that: The cooling system comprises a cooling air flow supply device (41), the cooling air flow supply device (41) comprising a cooling air flow supply box, an air supply pipe (22), a heater (411) and a flow valve (412), the cooling air flow supply box being connected to the air supply pipe (22), and the heater (411) and the flow valve (412) being both arranged on the air supply pipe (22) inside the cooling air flow supply box; The control system comprises a cooling airflow control module (31), the cooling airflow control module (31) comprises a temperature control module (311) and a flow control module (312), a controlled end of the heater (411) is connected to an output end of the temperature control module (311), and a controlled end of the flow valve (412) is connected to an output end of the flow control module (312); After a cooling airflow is introduced into the thermal barrier coating test piece (14), the thermocouple temperature feedback module (36) receives the temperature detection information of the first thermocouple (15) and compares it with the set temperature information, and then controls the heater (411) through the temperature control module (311) to control the temperature of the cooling airflow, and controls the flow valve (412) through the flow control module (312) to control the flow of the cooling airflow.

7. The flame tube thermal shock test device with cooling outflow according to claim 4, characterized in that: The cooling system further includes a flame spray gun water cooling device, the flame spray gun water cooling device including a cooling water tank (42) and a water cooling pipe (421), one end of the water cooling pipe (421) is connected to the cooling water tank (42), and the other end of the water cooling pipe (421) is connected to the water cooling pipe at the head of the flame spray gun (12), and a flow valve is provided on the water cooling pipe (421); The control system further comprises a water cooling control module (35), and the controlled end of the flow valve is connected to the output end of the water cooling control module (35).

8. The flame tube thermal shock test device with cooling outflow according to claim 4, characterized in that: The flame spray gun (12) is provided with an igniter (21) for ignition at the head thereof. The control system further comprises an ignition module (32). The igniter (21) ignites the combustible mixed gas sprayed from the flame spray gun (12) under the control of the ignition module (32).

9. Thermal shock test method for flame tube with cooling outflow, characterized in that: The following steps are involved: S1. The flame spray gun (12) is ignited and ejects high-temperature gas; S2. The thermal barrier coating specimen (14) is heated to a first preset temperature on one side facing the flame spray gun (12); S3. Maintaining the fuel flow rate of the flame spray gun (12) unchanged, continuing to generate high-temperature combustion gas, ensuring that the high-temperature side of the thermal barrier coating test piece (14) is maintained at a first preset temperature; passing a cooling airflow through the low-temperature side of the thermal barrier coating test piece (14) to cool it to a second preset temperature, so that a temperature gradient is formed in the thickness direction of the thermal barrier coating test piece (14), and a temperature gradient is formed along the airflow direction on the high-temperature side of the thermal barrier coating test piece (14) under the action of the small hole structure (141); S4. Ensure that the gas temperature and cooling air flow temperature remain unchanged and maintain this state for a period of time; S5. Controlling the temperature on both sides of the thermal barrier coating specimen (14) so that the thermal barrier coating specimen changes from the operating temperature of condition A to the operating temperature of condition B, and then from the operating temperature of condition B back to the operating temperature of condition A; S6. Repeat step S5. When the cracks on the thermal barrier coating specimen (14) reach a preset size or the coating falls off, stop the test and record the number of cycles.

10. The thermal shock test method for a flame tube with cooling outflow according to claim 9, characterized in that: The following steps are also included: According to the actual working conditions of the combustion chamber, the temperature variation law of the combustion gas side and the cooling gas side of the flame tube is obtained from the temperature cycle spectrum, and a simulation test is carried out according to this law; after the thermal barrier coating test piece (14) reaches the working condition A temperature, it is maintained for a period of time, and then the temperature on both sides of the thermal barrier coating test piece (14) is adjusted according to the cycle spectrum; if the working condition B temperature level is higher than the working condition A temperature, the temperature is continued to rise until the temperature on both sides of the thermal barrier coating test piece (14) reaches the specified temperature value; if the working condition B temperature level is lower than the working condition A temperature, the temperature of the high-temperature combustion gas sprayed by the flame spray gun (12) is reduced by controlling the size of the oil supply, and / or the heater (411) is adjusted to reduce the temperature of the cooling air flow, thereby reducing the temperature on both sides of the thermal barrier coating test piece (14).

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