Apparatus and method for extreme face load testing of aircraft sCO2 thermal protection components

Abstract

The present application relates to the technical field of aircraft active thermal protection test technology and thermal test equipment technology, in particular to a device and method for extreme surface load test of aircraft sCO2 thermal protection components, comprising a vacuum system, an electric induction heating system located inside the vacuum system, a supercritical carbon dioxide circulation system arranged outside the vacuum system, a supercritical carbon dioxide circulation pipeline extending into the vacuum system and located above the electric induction heating system and in communication with a test piece, and a medium supply system in communication with the supercritical carbon dioxide circulation system. The present application constructs a comprehensive test simulation device integrating a vacuum environment, electromagnetic induction heating, a supercritical cooling loop, high-precision measurement, data processing and a control system, and the overall structure of the device is compact, small in footprint and strong in expandability, and the device is suitable for thermal performance research of microstructure cooling units and components under high heat flow density and multi-physical field coupling conditions.

Description

Technical Field

[0001] This invention relates to the field of active thermal protection testing technology and thermal testing equipment for aircraft, and in particular to an extreme surface load testing device and method for CO2 thermal protection components of aircraft. Background Technology

[0002] With the continuous improvement of the adaptability of aerospace vehicles, advanced nuclear energy devices, and highly integrated electronic devices to extreme service conditions, the thermal loads faced by key structural components are constantly increasing, and the heat flux density in some areas has reached or even exceeded the MW / m² level. Under these circumstances, how to effectively cool these high heat flux density areas has become a core issue in thermal protection and enhanced heat transfer research. Supercritical carbon dioxide (sCO2) has become a strong candidate for the next generation of efficient cooling media due to its excellent thermophysical properties near the critical point, such as high specific heat, high thermal conductivity, low viscosity, and low interfacial tension, especially showing great potential in volume-constrained and mass-sensitive aerospace and energy systems.

[0003] However, experimental research on sCO2 cooling circuits under high heat flux density conditions is relatively lagging, especially in practical engineering scenarios such as multi-scale structures, complex flow channel arrangements, and unsteady high heat loads, where an integrated comprehensive experimental platform is still lacking. Existing experimental systems mostly use heating methods such as resistance wires, quartz lamps, or electron beams, which have problems such as low upper limits of heat flux density, uneven heat field distribution, and limited space arrangement, making it difficult to meet the requirements for curved structures, large-area loading, and long-term stable heating at high temperatures. At the same time, traditional contact heating methods cannot meet the requirements of structural integrity, especially in vacuum high-temperature environments, where their stability and reliability are severely limited.

[0004] Furthermore, regarding cooling channels, most studies are limited to single-path conditions, failing to fully consider complex influencing factors such as multi-channel parallel operation, uneven flow distribution, and local hot spots in the system. Research on multi-branch, multi-module pipe network layouts is still immature, and there is a lack of systematic data support for assessing the uniformity of the structural thermal field and thermal stress response. In terms of measurement technology, existing systems often only have a limited number of thermocouple measuring points, lacking the ability to simultaneously observe multi-physics fields such as temperature, deformation, and flow fields, resulting in significant gaps in our understanding of the thermal flow response mechanism.

[0005] In view of the above shortcomings, there is an urgent need to construct a comprehensive test system that integrates high heat flux density loading, supercritical cooling flow path control, and multi-source observation of temperature and deformation. Summary of the Invention

[0006] The purpose of this invention is to provide an extreme surface load test device and method for CO2 thermal protection components of aircraft. It constructs a comprehensive test simulation device that integrates vacuum environment, electromagnetic induction heating, supercritical cooling circuit, mechanical load loading, high-precision measurement, data processing and control system. The device has a compact overall structure, small footprint, and strong scalability. It is suitable for the study of the thermodynamic performance of microstructure cooling units and components under high heat flux density and multi-physics field coupling conditions.

[0007] To achieve the above objectives, the present invention provides an extreme surface load test device for CO2 thermal protection components of aircraft, comprising a vacuum system, an induction heating system, a supercritical carbon dioxide circulation system, a data acquisition system, a medium supply system, and a cooling water circulation system. The induction heating system is located inside the vacuum system, the supercritical carbon dioxide circulation system is located outside the vacuum system, the supercritical carbon dioxide circulation pipe of the supercritical carbon dioxide circulation system extends into the vacuum system and is located above the induction heating system and connected to the test specimen, the medium supply system is connected to the supercritical carbon dioxide circulation system, the data acquisition system is electrically connected to the induction heating system and the test specimen, and the cooling water circulation system is connected to the vacuum system and the supercritical carbon dioxide circulation system.

[0008] Preferably, the vacuum system includes a vacuum chamber, a vacuum pump, and a vacuum valve. The vacuum pump is located outside the vacuum chamber and is connected to the vacuum chamber through a vacuum pipe. The vacuum pipe is equipped with a vacuum valve. The top of the vacuum chamber is equipped with an observation window. The side wall of the vacuum chamber is equipped with a wiring through hole and a pipe through hole. Both the wiring through hole and the pipe through hole are equipped with a sealing structure.

[0009] In a further preferred embodiment, a door is provided on the front side of the vacuum chamber, and a sealing structure is provided at the connection between the door and the vacuum chamber, the sealing structure including a sealing gasket.

[0010] Preferably, the induction heating system is located at the bottom center of the vacuum chamber, including an induction coil and a graphite block disposed on the upper side of the induction coil. The induction coil is fixedly connected to the inner wall of the vacuum chamber through a bracket. The induction coil is electrically connected to an external power source. A heat insulation layer is provided between the induction coil and the graphite block.

[0011] Preferably, the outer side of the induction coil is wrapped with glass fiber and / or clay, and the heat insulation layer is zirconia felt and / or asbestos.

[0012] Preferably, the supercritical carbon dioxide circulation system includes a high-pressure vessel and a supercritical carbon dioxide circulation pipeline. The supercritical carbon dioxide circulation pipeline includes a destination pipeline and a return pipeline. One end of the destination pipeline and the return pipeline are connected to the high-pressure vessel, and the other end of the destination pipeline and the return pipeline extend into the vacuum system and are connected to the test specimen.

[0013] Preferably, a magnetic pump is provided at the end of the outgoing pipeline near the high-pressure vessel, and a pressure measuring component 1 and a temperature measuring component 1 are provided at the end of the outgoing pipeline near the vacuum system. Flow meters 1 and 2 are connected in parallel in the middle of the outgoing pipeline. The two sides of flow meter 1 are connected to control valve 1 and control valve 2, respectively, and the two sides of flow meter 2 are connected to control valve 3 and control valve 4, respectively. The end of the return pipeline near the high-pressure vessel is connected to the cooling water circulation system, and a pressure measuring component 2 and a temperature measuring component 2 are provided at the end of the return pipeline near the vacuum system. A pressure measuring component 3 and a temperature measuring component 4 are provided on the high-pressure vessel.

[0014] Preferably, the data acquisition system includes a thermocouple array, an infrared temperature measurement module, and a DIC three-dimensional deformation measurement module. The thermocouple array is inserted into a pre-set temperature measurement hole on the specimen and connected to the data acquisition module via wires. The infrared temperature measurement module and the DIC three-dimensional deformation measurement module are located on the upper side of the observation window. The data acquisition module, the infrared temperature measurement module, and the DIC three-dimensional deformation measurement module are all connected to a computer via signal lines.

[0015] Preferably, the medium supply system includes multiple high-purity carbon dioxide cylinders and a compressor. The high-purity carbon dioxide cylinders are connected to the compressor via a pressure reducing valve, and the compressor is connected to a high-pressure container via an exhaust valve.

[0016] Preferably, the cooling water circulation system includes a heat exchanger, a water chiller, a first cooling water circulation pipeline, and a second cooling water circulation pipeline. The heat exchanger is connected to the supercritical carbon dioxide circulation pipeline and is connected to the water chiller through the first cooling water circulation pipeline. A cooling chamber is provided outside the shell of the vacuum chamber and is connected to the water chiller through the second cooling water circulation pipeline.

[0017] The present invention also provides a test method using the above-mentioned extreme surface load test device for CO2 thermal protection components of aircraft, comprising the following steps:

[0018] S1. Connect the inlet and outlet of the test specimen to the supercritical carbon dioxide circulation pipeline.

[0019] S2. Debug the data acquisition module, infrared temperature measurement module and DIC three-dimensional deformation measurement module of the data acquisition system;

[0020] S3. Start the vacuum system, open the pressure reducing valve on the high-purity carbon dioxide cylinder of the medium supply system, and pressurize the carbon dioxide gas to the pressure of supercritical carbon dioxide through the compressor and then deliver it to the high-pressure container for storage.

[0021] S4. Start the supercritical carbon dioxide circulation system and the induction heating system. After the system is running stably, start the data acquisition system to collect data.

[0022] S5. Adjust the supercritical carbon dioxide circulation system and / or the induction heating system, change the flow rate of supercritical carbon dioxide and / or the heat flux density of electromagnetic induction heating, and repeat step S4.

[0023] S6. After the test is completed, turn off the induction heating system and wait for the specimen temperature to approach room temperature. Turn off the supercritical carbon dioxide circulation system, open the vacuum valve of the vacuum system and wait for the pressure to return to atmospheric pressure. Open the vacuum chamber door and replace the specimen. Repeat S1-S6 until all specimens have completed the test.

[0024] The present invention employs the above-mentioned test apparatus and method for extreme surface loads of CO2 thermal protection components of aircraft, and has the following beneficial effects:

[0025] (1) The induction heating system of the present invention has a high heat flux density loading capability. It adopts electromagnetic induction heating combined with graphite radiation, which can realize surface heating, zone control and time-varying loading. It has high heat flux density and uniform thermal field, and can simulate the extreme thermal environment required by the thermal protection components of aircraft.

[0026] (2) The supercritical carbon dioxide circulation system of the present invention is stable and reliable. It uses a variable frequency magnetic pump as the core driving device to achieve wide-range and stable supercritical CO2 flow control. It is suitable for the study of cooling performance under different structures and working conditions. The magnetic pump operates stably, without leakage or mechanical wear, and supports long-term continuous operation.

[0027] (3) The data acquisition system of the present invention integrates a thermocouple array, an infrared temperature measurement module and a DIC three-dimensional deformation measurement module, which can simultaneously acquire the temperature field, strain field and surface change process of the specimen, with high measurement accuracy and rich data.

[0028] (4) The vacuum system of the present invention provides good vacuum environment support, effectively avoids the oxidation reaction of graphite and metal materials at high temperature, and eliminates aerodynamic interference, thereby improving the repeatability and observation accuracy of the experiment.

[0029] (5) The test device of the present invention has strong adaptability and a wide range of test types. It is suitable for thermo-mechanical coupling tests of single tubes, flat plates and multi-module components, and supports mechanical loads such as tension, compression and torsion, covering the thermo-mechanical coupling response characteristics under typical flight conditions. In addition, the test device has a compact structure, is easy to operate, has low cost, simple principle, strong maintainability and engineering promotion, and relatively low overall manufacturing and operating costs, making it suitable for laboratory and engineering applications.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] Figure 1This is a schematic diagram of the layout of the extreme surface load test device for the CO2 thermal protection components of the aircraft of the present invention;

[0032] Figure 2 This is a schematic diagram of the connection between the single-tube specimen and the outgoing and return pipelines in Embodiment 2 of the present invention;

[0033] Figure 3 This is a schematic diagram of the connection between the flat plate specimen and the outgoing and return pipelines in Embodiment 3 of the present invention;

[0034] Figure 4 This is a flowchart of the test procedure for the extreme surface load test device for CO2 thermal protection components of an aircraft, as described in this invention.

[0035] Figure 5 This is a graph showing the temperature change of the heating surface of single-tube specimens with different channel shapes in Example 2 as the heat flux density increases.

[0036] Figure label:

[0037] 1. Vacuum system; 11. Vacuum chamber; 12. Observation window; 13. Cooling chamber;

[0038] 2. Induction heating system; 21. Induction coil; 22. Graphite block; 23. Support; 24. Insulation layer;

[0039] 3. Supercritical carbon dioxide circulation system; 31. High-pressure vessel; 32. Outbound pipeline; 33. Return pipeline; 34. Magnetic pump; 35. Flow meter one; 36. Flow meter two; 37. Control valve one; 38. Control valve two; 39. Control valve three; 310. Control valve four; 311. Pressure measurement assembly one; 312. Temperature measurement assembly one; 313. Pressure measurement assembly two; 314. Temperature measurement assembly two; 315. Pressure measurement assembly three; 316. Temperature measurement assembly three;

[0040] 4. Data acquisition system; 41. Thermocouple array; 42. Infrared temperature measurement module; 43. DIC three-dimensional deformation measurement module; 44. Computer;

[0041] 5. Media supply system; 51. High-purity carbon dioxide cylinder; 52. Compressor; 53. Exhaust valve;

[0042] 6. Cooling water circulation system; 61. Heat exchanger; 62. Water chiller; 63. Cooling water circulation pipeline one; 64. Cooling water circulation pipeline two;

[0043] 7. Specimen; 8. Compression fitting; 9. Flange. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0045] Example 1

[0046] like Figures 1 to 4 As shown, the present invention provides an extreme surface load test device for CO2 thermal protection components of aircraft, including a vacuum system 1, an induction heating system 2, a supercritical carbon dioxide circulation system 3, a data acquisition system 4, a medium supply system 5, and a cooling water circulation system 6. The induction heating system 2 is located inside the vacuum system 1, the supercritical carbon dioxide circulation system 3 is located outside the vacuum system 1, the supercritical carbon dioxide circulation pipe of the supercritical carbon dioxide circulation system 3 extends into the vacuum system 1 and is located above the induction heating system 2 and communicates with the test specimen 7. The medium supply system 5 is connected to the supercritical carbon dioxide circulation system 3. The data acquisition system 4 is electrically connected to the induction heating system 2 and the test specimen 7. The cooling water circulation system 6 is connected to the vacuum system 1 and the supercritical carbon dioxide circulation system 3.

[0047] Vacuum system 1 includes a vacuum chamber 11, a vacuum pump, and vacuum valves. The vacuum pump is located outside the vacuum chamber 11 and is connected to the vacuum chamber 11 via a vacuum pipe. The vacuum chamber 11 is fixed to the ground by a support frame as used in the prior art. Vacuum valves are installed on the vacuum pipes. The vacuum pump extracts air from the vacuum chamber 11 through the vacuum pipes, and the vacuum valves control the pumping rate and vacuum level. An observation window 12 is located on the top of the vacuum chamber 11 for monitoring the status of the test piece 7 using external optical measuring equipment. Wiring through holes and pipe through holes are provided on the side walls of the vacuum chamber 11. A hatch is located on the front side of the vacuum chamber 11. Sealing structures are provided at the connection between the hatch and the vacuum chamber 11, as well as inside the wiring through holes and pipe through holes. The sealing structures include sealing gaskets to prevent air leakage.

[0048] Vacuum system 1 achieves a stable vacuum environment on the order of 1000 Pa through a vacuum pump and vacuum valves, effectively preventing graphite oxidation at high temperatures and significantly improving the durability and service life of the heating system. Simultaneously, it eliminates interference from air convection and radiation, reducing errors in optical measurements (such as DIC and infrared thermometry) and ensuring the accuracy of temperature and deformation field data. The sealing structure of vacuum chamber 11 (sealing gaskets, wiring / pipeline through-hole seals) ensures the stability of the low-pressure environment. The observation window 12 facilitates real-time monitoring of the test specimen 7 by external equipment, while the door structure facilitates the installation and replacement of the specimen 7, balancing experimental safety and operational convenience.

[0049] The induction heating system 2 is located at the bottom center of the vacuum chamber 11, and includes an induction coil 21 and a graphite block 22 disposed on the upper side of the induction coil 21. The induction coil 21 is fixedly connected to the inner wall of the vacuum chamber 11 via a bracket 23. The induction coil 21 is electrically connected to an external medium-frequency induction power supply. A heat insulation layer 24 is provided between the induction coil 21 and the graphite block 22. The induction coil 21 is a copper coil, and the outer side of the copper coil is wrapped with glass fiber and / or clay, which has both high temperature resistance and insulation properties, avoiding the risk of discharge in the vacuum environment. The heat insulation layer 24 is made of zirconia felt and / or asbestos, which reduces heat loss, improves energy utilization efficiency, and protects the coil from high temperature damage. The area of ​​the graphite block 22 matches the size of the specimen 7, which includes single-tube specimens, flat plate specimens, and multi-module specimens.

[0050] The induction heating system 2 uses electromagnetic induction to heat the graphite block 22. When an alternating current is applied to the induction coil 21, an alternating magnetic field is generated. The graphite radiator placed in the magnetic field generates eddy currents (induced current) due to electromagnetic induction. As the current flows inside the graphite, it is converted into heat energy due to resistance, causing the graphite's temperature to rise (approaching 2000℃). The graphite block 22, acting as a radiator, transfers heat energy to the surface of the specimen 7 via infrared radiation, achieving non-contact surface heating with a heat flux density of 0.2~2 MW / m³. 2 It covers extreme thermal load scenarios, and can control the heat flux density and heating time by controlling the current of the induction coil 21. Moreover, the area of ​​the graphite block 22 matches that of the specimen 7, and the thermal field uniformity is high, which can simulate the actual heating state of complex curved surfaces and large-area specimens 7.

[0051] Heat flux density The calculation formula is based on the temperature difference between the graphite block and the test piece:

[0052] ;

[0053] In the formula, To accept the angle coefficient of the graphite block surface to the heated surface of the test piece; It is the Stefan-Boltzmann constant; The long-wave emissivity of graphite blocks, T c It is the graphite temperature, in K; T x It is the temperature of the test specimen, in K; Infrared transmittance.

[0054] The supercritical carbon dioxide circulation system 3 includes a high-pressure vessel 31 and a supercritical carbon dioxide circulation pipeline. The high-pressure vessel 31 stores supercritical carbon dioxide. The supercritical carbon dioxide circulation pipeline includes a destination pipeline 32 and a return pipeline 33. One end of both the destination pipeline 32 and the return pipeline 33 is connected to the high-pressure vessel 31, and the other end of both extends into the vacuum system 1 and is connected to the specimen 7. The destination pipeline 32 delivers supercritical carbon dioxide to the specimen 7 in the vacuum chamber 11 to cool the specimen 7. The return pipeline 33 returns the supercritical carbon dioxide after it has absorbed heat, and it is cooled by the heat exchanger 61 and reused.

[0055] When specimen 7 is a single-pipe specimen, the air inlet and outlet of specimen 7 are fixedly connected to the outgoing pipeline 32 and the return pipeline 33 respectively through compression fittings 8. When specimen 7 is a flat plate specimen or a multi-module specimen, the air inlet and outlet of specimen 7 are fixedly connected to the outgoing pipeline 32 and the return pipeline 33 respectively through flanges 9.

[0056] A magnetic pump 34 (a variable frequency magnetic pump 34) is installed at the end of the outgoing pipeline 32 near the high-pressure vessel 31. The magnetic pump 34 drives supercritical carbon dioxide to circulate in the outgoing pipeline 32 and the return pipeline 33. Flowmeter 35 and flowmeter 36 are connected in parallel in the middle of the outgoing pipeline 32. Flowmeter 35 is connected to control valve 37 and control valve 38 on both sides. Flowmeter 36 is connected to control valve 39 and control valve 310 on both sides. Flowmeter 35 is a low-speed flowmeter, and flowmeter 36 is a high-speed flowmeter. By switching the control valves, a flowmeter with an appropriate range can be selected according to the specific flow rate conditions, ensuring accurate measurement across different flow rate ranges, balancing measurement accuracy in both low-speed and high-speed sections.

[0057] The outgoing pipeline 32, near the vacuum system 1, is equipped with a pressure measuring component 311 and a temperature measuring component 312. The return pipeline 33, near the vacuum system 1, is equipped with a pressure measuring component 313 and a temperature measuring component 314. The high-pressure vessel 31 is equipped with a pressure measuring component 315 and a temperature measuring component 316. The temperature measuring components can be thermometers or temperature sensors from the prior art, and the pressure measuring components can be pressure gauges or pressure sensors from the prior art, used to monitor the state of supercritical carbon dioxide.

[0058] The end of the loop pipe 33 closest to the high-pressure vessel 31 is connected to the cooling water circulation system 6. The cooling water circulation system 6 dissipates heat from the induction coil 21, the vacuum chamber 11 shell, and the supercritical carbon dioxide, ensuring long-term stable operation of the system. The cooling water circulation system 6 includes a heat exchanger 61, a water chiller 62, a first cooling water circulation pipe 63, and a second cooling water circulation pipe 64. The heat exchanger 61 is connected to the supercritical carbon dioxide circulation pipe to cool the high-temperature supercritical carbon dioxide returning from the test specimen 7.

[0059] Heat exchanger 61 is connected to water chiller 62 via cooling water circulation pipe 63. Water chiller 62 cools the circulating cooling water to ensure stable heat dissipation. A cooling chamber 13 is located outside the shell of vacuum chamber 11. Cooling chamber 13 is connected to water chiller 62 via cooling water circulation pipe 64, supplying cooling water to the cooling chamber 13 to cool the shell of vacuum chamber 11 and the induction coil 21 inside vacuum chamber 11. However, the temperature difference between cooling chamber 13 and the inside of vacuum chamber 11 must be less than 10℃ (the temperature difference can be monitored by infrared temperature measurement module 42 and controlled in conjunction with water chiller 62) to avoid condensation droplets damaging the system.

[0060] The medium supply system 5 includes multiple high-purity carbon dioxide cylinders 51 and a compressor 52. The high-purity carbon dioxide cylinders 51 are connected to the compressor 52 via pressure reducing valves, and the compressor 52 is connected to the high-pressure container 31 via an exhaust valve 53. The carbon dioxide in the high-purity carbon dioxide cylinders 51 is reduced to 0.1~0.3 MPa by the pressure reducing valves, then pressurized to 8~12 MPa by the compressor 52, and finally stored in the high-pressure container 31. This solves the problem of difficult gas release at low temperatures in winter and enables long-term high-pressure gas supply. The pressure of the pressure reducing valves is adjusted according to the required pressure, as shown in Table 1 below.

[0061] Table 1 Output pressure of pressure reducing valve and compressor

[0062] ;

[0063] The data acquisition system 4 includes a thermocouple array 41, an infrared temperature measurement module 42, and a DIC three-dimensional deformation measurement module 43. The thermocouple array 41 is inserted into the preset temperature measurement hole of the specimen 7 and connected to the data acquisition module through wires. The infrared temperature measurement module 42 and the DIC three-dimensional deformation measurement module 43 are located on the upper side of the observation window 12. The data acquisition module, the infrared temperature measurement module 42, and the DIC three-dimensional deformation measurement module 43 are all connected to the computer 44 through signal lines.

[0064] Thermocouple array 41 is inserted into the temperature measuring hole of specimen 7. The temperature signal is converted into an electrical signal by the data acquisition module and transmitted to computer 44. Infrared temperature measurement module 42 monitors the high-temperature area on the surface of specimen 7 through observation window 12 to assist in calibrating thermocouple data; DIC three-dimensional deformation measurement module 43 illuminates the speckle pattern on the surface of specimen 7 with a blue light source. The dual cameras capture deformation images, and the three-dimensional strain field is obtained by software analysis. The temperature field (accuracy ±0.1%), strain field, and structural deformation can be acquired simultaneously to realize temperature-deformation-flow multiphysics field correlation analysis.

[0065] Example 2

[0066] The present invention also provides a test method for using the extreme surface load test device for aircraft CO2 thermal protection components of Embodiment 1, wherein the specimen 7 is a single tube specimen, and includes the following steps:

[0067] S1. Install the single-tube specimen after pretreatment.

[0068] S1.1 Use 800-1500# sandpaper to polish the surface of the single tube specimen to be tested, clean it with alcohol and then prepare speckle patterns. For medium high temperature conditions (<1000℃), use white primer + black paint; for high temperature conditions (>1000℃), use tantalum carbide powder to ensure that the speckle pattern is clear and uniform.

[0069] S1.2. The air inlet of the single tube specimen is fixedly connected to the end of the outgoing pipeline 32 extending into the vacuum chamber 11 through the compression fitting 8. The air outlet of the single tube specimen is fixedly connected to the end of the return pipeline 33 extending into the vacuum chamber 11 through the compression fitting 8. The compression fitting 8 can be a suitable model in the prior art. All compression fittings 8 are sealed with raw rubber tape.

[0070] S2, Debugging the data acquisition system 4

[0071] Insert a thermocouple (0.5 mm in diameter) into the pre-set temperature measurement hole (0.6 mm in diameter) of the single tube specimen and connect it to the data acquisition module. Set up the infrared temperature measurement module 42 and align it with the single tube specimen. Debug the DIC three-dimensional deformation measurement module 43 (adjust the blue light source, camera focal length and polarizer to ensure that the grayscale of the speckle image is 70±5).

[0072] S3, Start vacuum system 1 and media supply system 5

[0073] S3.1 Check the vacuum system 1 (close the door and confirm the status of the vacuum valve), the medium supply system 5 (connect the high-purity carbon dioxide cylinder 51 to the pressure reducing valve) and the cooling water circulation system 6 (start the water chiller 62 and check that the pipeline is unobstructed).

[0074] S3.2 Start the vacuum pump and extract air from the vacuum chamber 11 through the vacuum pipeline. Use the vacuum valve to stabilize the vacuum level at 1000 Pa to avoid high-temperature oxidation of the graphite block 22 and interference from air on optical measurements.

[0075] S3.3 Open the high-purity carbon dioxide cylinder 51 and adjust the pressure to 0.1~0.3MPa using the pressure reducing valve. Start the compressor 52 to pressurize the carbon dioxide to 7~10MPa and deliver it to the high-pressure container 31 for storage. Observe the pressure gauge of the compressor 52 (oil pressure ≥0.25MPa, oil discharge pressure is 5MPa higher than discharge pressure) and the pressure measuring component 315. After the pressure stabilizes, turn off the compressor 52 and the high-purity carbon dioxide cylinder 51.

[0076] S4. Test Parameter Setting and Loading

[0077] S4.1. Start the magnetic pump 34 of the supercritical carbon dioxide circulation system 3, control the flow rate of supercritical carbon dioxide to 4~8.5m / s, and start the cold water circulation system at the same time.

[0078] Open control valve 1 (37) and control valve 2 (38), close control valve 3 (39) and control valve 4 (310), and use flow meter 1 (35) to monitor the flow rate of supercritical carbon dioxide in the outgoing pipeline 32. Close control valve 1 (37) and control valve 2 (38), open control valve 3 (39) and control valve 4 (310), and use flow meter 2 (36) to monitor the flow rate of supercritical carbon dioxide in the outgoing pipeline 32. The range of flow meter 1 (35) is 5~10 m / s, and the range of flow meter 2 (36) is 0.5~5 m / s.

[0079] S4.2. The induction heating system 2 uses a graphite block 22 of a size matching the area of ​​the single-tube specimen. The medium-frequency induction power supply of the induction heating system 2 is turned on, and the temperature of the graphite block 22 (1100~2200℃) is controlled by adjusting the current. A heat flux density (0.2~2MW / m³) is applied to the single-tube specimen by infrared radiation. 2 After the system is running stably, start the data acquisition system 4 to collect data.

[0080] S4.3 The data acquisition method is to record the internal temperature of the single tube specimen through the thermocouple array 41 (acquisition frequency 2Hz); monitor the high temperature area on the surface of the single tube specimen through the infrared temperature measurement module 42; and collect the strain field to analyze the structural deformation through the DIC three-dimensional deformation measurement module 43.

[0081] S5. After completing the current operating condition, keep the pressure constant and switch to the next operating condition by changing the frequency of the magnetic pump 34 (to adjust the flow rate) and the induced current (to adjust the heat flux density). Repeat the data acquisition steps in S4.3 until all preset operating conditions are covered (e.g., flow rate 4~8.5m / s, heat flux density 190~900kW / m³). 2 The collected experimental data are shown in Table 2.

[0082] S6. After the test is completed, turn off the induction heating system and wait for the temperature of the single tube specimen to approach room temperature. Turn off the supercritical carbon dioxide circulation system 3, open the vacuum valve of the vacuum system 1 and wait for the pressure to return to atmospheric pressure. Open the door of the vacuum chamber 11 and replace the single tube specimen (the channels of the single tube specimen are circular, rectangular, square-circular, elliptical, bean-shaped, and highly elliptical). Repeat S1-S6 until all specimens 7 have completed the test.

[0083] Example 3

[0084] This invention also provides a test method for the extreme surface load test device for the CO2 thermal protection components of an aircraft using the method described in Example 1. The specimen 7 is a flat plate specimen. The difference from Example 2 is that in step S1.2, the air inlet and outlet of the flat plate specimen are fixedly connected to the outgoing pipe 32 and the return pipe 33 respectively via flanges 9. Suitable models of flanges 9 from the prior art can be selected, and the joints of flanges 9 are sealed with Teflon tape. In step S4.1, the flow rate of supercritical carbon dioxide is 0.5~4.5 m / s. In step S4.2, the induction heating system 2 uses a graphite block 22 of a size matching the area of ​​the flat plate specimen. The experimental data collected in step S5 are shown in Table 3. The rest is the same as in Example 2.

[0085] Example 4

[0086] The present invention also provides a test method for using the extreme surface load test device for aircraft CO2 thermal protection components of Embodiment 1. The difference from Embodiment 3 is that the test specimen 7 is a multi-module test specimen, and the rest is the same as Embodiment 3.

[0087] Experimental data analysis

[0088] Figure 5 For single-tube specimens with different channel shapes in Example 2, the temperature change curves of their heating surfaces as the heat flux density increases are shown under constant pressure and supercritical carbon dioxide flow rate. Figure 5 It can be seen that as the heat flux density increases, the temperature of the heated surface increases significantly. The experimental results are reasonable and indicate the feasibility of the experimental device.

[0089] In Example 2, step S5, the initial pressure of the high-pressure vessel was maintained at 8.0 MPa (the pressure and temperature of supercritical carbon dioxide will fluctuate with the duration of the experiment and the heat dissipation effect of the magnetic pump). The temperature and strain fields of the single-tube specimen were tested under different supercritical carbon dioxide flow rates and different heat flux densities to analyze the heat transfer performance and structural response of the specimen. The results are shown in Table 2.

[0090] Table 2. Experimental data of the single-tube specimen collected in Example 2.

[0091] ;

[0092] In Table 2, thermocouple 1 and thermocouple 2 are inserted vertically at the midpoint between the heating surface and the flow channel of the single-tube specimen. Thermocouple 1 is positioned 1 mm from the heating surface, and thermocouple 2 is 3 mm away from thermocouple 1. Based on Fourier's law, the heat flux density and average surface temperature are calculated using the temperatures collected by thermocouples 1 and 2 and the distance between the thermocouples. Then, the heat transfer coefficient is calculated using Newton's law of cooling.

[0093] In step S5 of Example 3, the initial pressure of the high-pressure vessel was maintained at 9.0 MPa (the pressure and temperature of supercritical carbon dioxide will fluctuate with the duration of the experiment and the heat dissipation of the magnetic pump). The temperature and strain fields of the plate specimen under different supercritical carbon dioxide flow rates and different heat flux densities were analyzed to determine the heat transfer performance and structural response of the specimen. The results are shown in Table 3.

[0094] Table 3. Experimental data of the flat plate specimen collected in Example 3.

[0095] ;

[0096] Compared with single-tube specimens, plate specimens are thinner, so the method of calculating heat flux density by measuring the temperature of thermocouple one and thermocouple two is no longer applicable. Instead, the heat flux density is calculated using the enthalpy values ​​of the inlet and outlet. The thermocouples are attached to the upper surface of the plate, and the temperature of the non-heated surface is collected.

[0097] As shown in Tables 2 and 3, both the single-tube and flat-plate specimens achieved heat flux densities of 0.03–2 MW / m³. 2 The system allows for wide-range control of pressure (8-11 MPa) and flow rate (0.5-10 m / s), covering the extreme load range (high heat flux, high pressure, high-speed cooling) of aircraft thermal protection components. It verifies the flow and heat transfer characteristics of supercritical CO2 in different specimens, providing experimental basis for the structural design (such as channel shape and size) and parameter matching (pressure-flow rate-heat flux) of thermal protection components.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An extreme surface load testing device for CO2 thermal protection components of aircraft, characterized in that: It includes a vacuum system, an induction heating system, a supercritical carbon dioxide circulation system, a data acquisition system, a media supply system, and a cooling water circulation system. The induction heating system is located inside the vacuum system, the supercritical carbon dioxide circulation system is located outside the vacuum system, the supercritical carbon dioxide circulation pipe of the supercritical carbon dioxide circulation system extends into the vacuum system and is located above the induction heating system and connected to the specimen. The media supply system is connected to the supercritical carbon dioxide circulation system, the data acquisition system is electrically connected to the induction heating system and the specimen, and the cooling water circulation system is connected to the vacuum system and the supercritical carbon dioxide circulation system. The supercritical carbon dioxide circulation system includes a high-pressure vessel and a supercritical carbon dioxide circulation pipeline. The supercritical carbon dioxide circulation pipeline includes an outgoing pipeline and a return pipeline. One end of the outgoing pipeline and the return pipeline are connected to the high-pressure vessel, and the other end of the outgoing pipeline and the return pipeline extend into the vacuum system and are connected to the test specimen. A magnetic pump is installed at the end of the outgoing pipeline near the high-pressure vessel. A pressure measuring component 1 and a temperature measuring component 1 are installed at the end of the outgoing pipeline near the vacuum system. Flow meters 1 and 2 are installed in parallel in the middle of the outgoing pipeline. The two sides of flow meter 1 are connected to control valve 1 and control valve 2, respectively. The two sides of flow meter 2 are connected to control valve 3 and control valve 4, respectively. The end of the return pipeline near the high-pressure vessel is connected to the cooling water circulation system. A pressure measuring component 2 and a temperature measuring component 2 are installed at the end of the return pipeline near the vacuum system. A pressure measuring component 3 and a temperature measuring component 3 are installed on the high-pressure vessel.

2. The extreme surface load test device for CO2 thermal protection components of aircraft according to claim 1, characterized in that: The vacuum system includes a vacuum chamber, a vacuum pump, and vacuum valves. The vacuum pump is located outside the vacuum chamber and is connected to the vacuum chamber through a vacuum pipe. The vacuum pipe is equipped with a vacuum valve. The top of the vacuum chamber is equipped with an observation window. The side wall of the vacuum chamber is equipped with wiring through holes and pipe through holes, and both wiring through holes and pipe through holes are equipped with sealing structures.

3. The extreme surface load test device for CO2 thermal protection components of aircraft according to claim 2, characterized in that: The induction heating system is located at the bottom center of the vacuum chamber and includes an induction coil and a graphite block placed on the upper side of the induction coil. The induction coil is fixedly connected to the inner wall of the vacuum chamber through a bracket. The induction coil is electrically connected to an external power source. A heat insulation layer is provided between the induction coil and the graphite block.

4. The extreme surface load test device for CO2 thermal protection components of aircraft according to claim 3, characterized in that: The outer side of the induction coil is wrapped with glass fiber and / or clay, and the heat insulation layer is zirconia felt and / or asbestos.

5. The extreme surface load test device for CO2 thermal protection components of aircraft according to claim 2, characterized in that: The data acquisition system includes a thermocouple array, an infrared temperature measurement module, and a DIC three-dimensional deformation measurement module. The thermocouple array is inserted into the pre-set temperature measurement hole of the specimen and connected to the data acquisition module through wires. The infrared temperature measurement module and the DIC three-dimensional deformation measurement module are set on the upper side of the observation window. The data acquisition module, the infrared temperature measurement module, and the DIC three-dimensional deformation measurement module are all connected to the computer through signal lines.

6. The extreme surface load test device for CO2 thermal protection components of aircraft according to claim 1, characterized in that: The media supply system includes multiple high-purity carbon dioxide cylinders and a compressor. The high-purity carbon dioxide cylinders are connected to the compressor through a pressure reducing valve, and the compressor is connected to the high-pressure container through an exhaust valve.

7. The extreme surface load test device for CO2 thermal protection components of aircraft according to claim 1, characterized in that: The cooling water circulation system includes a heat exchanger, a water chiller, a first cooling water circulation pipeline, and a second cooling water circulation pipeline. The heat exchanger is connected to the supercritical carbon dioxide circulation pipeline and is connected to the water chiller through the first cooling water circulation pipeline. The vacuum chamber has a cooling chamber on its outer shell, which is connected to the water chiller through the second cooling water circulation pipeline.

8. A test method using the extreme surface load test apparatus for aircraft CO2 thermal protection components according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Connect the inlet and outlet of the test specimen to the supercritical carbon dioxide circulation pipeline. S2. Debug the data acquisition module, infrared temperature measurement module and DIC three-dimensional deformation measurement module of the data acquisition system; S3. Start the vacuum system and open the pressure reducing valve on the high-purity carbon dioxide cylinder of the medium supply system to deliver carbon dioxide gas to the high-pressure container through the compressor until the pressure of supercritical carbon dioxide is reached in the high-pressure container. S4. Start the supercritical carbon dioxide circulation system and the induction heating system. After the system is running stably, start the data acquisition system to collect data. S5. Adjust the supercritical carbon dioxide circulation system and / or the induction heating system, change the flow rate of supercritical carbon dioxide and / or the heat flux density of electromagnetic induction heating, and repeat step S4. S6. After the test is completed, turn off the induction heating system and wait for the specimen temperature to approach room temperature. Turn off the supercritical carbon dioxide circulation system, open the vacuum valve of the vacuum system and wait for the pressure to return to atmospheric pressure. Open the vacuum chamber door and replace the specimen. Repeat S1-S6 until all specimens have completed the test.

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