A test evaluation device and method for rocket engine plume afterburning effect

Abstract

The present application belongs to the technical field of rocket engine exhaust infrared radiation testing, and particularly relates to a device and method for testing and evaluating the rocket engine exhaust afterburning effect, comprising a low-pressure simulation cabin system, a temperature control system, an oxygen-free environment control system and a measurement system; the low-pressure simulation cabin system comprises a low-pressure cabin body, a vacuum pump group, a vacuum gauge, an air inlet proportional valve, a small air-breathing wind tunnel, a pressure adjustment controller, an air extraction pipeline, an air inlet pipeline and an exhaust switching valve; the temperature control system comprises a temperature sampler, a refrigeration coil, an electric heater, an air return pipe and a temperature adjustment controller; the oxygen-free environment control system comprises a liquid nitrogen source, a nitrogen gas inlet valve, a nitrogen gas inlet controller and an atomizing nozzle; the measurement system comprises a spectrometer, a thermal imager, a high-speed camera and a measurement system synchronous controller; the present application solves the problem that the existing research on the exhaust afterburning effect is only through numerical simulation and cannot be verified by experimental measurement.

Description

Technical Field

[0001] This invention relates to the field of infrared radiation testing technology for rocket engine exhaust plumes, specifically to a testing and evaluation device and method for the reignition effect of rocket engine exhaust plumes. Background Technology

[0002] The rocket engine exhaust plume is a high-temperature, high-speed, multi-component jet of propellant that has burned in the combustion chamber, been compressed and expanded through a Laval nozzle, and then ejected into the environment. Incomplete combustion of fuel-rich propellant produces unstable components at the nozzle. These components mix with air and undergo secondary combustion with oxygen, releasing a large amount of heat and significantly raising the exhaust plume temperature. This re-ignition effect significantly enhances the infrared radiation signal of the exhaust plume, meaning the degree of re-ignition can be assessed using the exhaust plume's infrared radiation signal.

[0003] Currently, research on the reignition effect of exhaust plumes heavily relies on numerical simulation methods for rocket engines. While numerical simulation offers advantages such as low cost, short cycle time, and easy parameter control in reignition effect studies, and can quickly obtain full-field flow and component distribution data, its results are heavily dependent on the accuracy of turbulence, combustion, and chemical reaction kinetic models. It suffers from significant prediction uncertainties under the coupled conditions of strong turbulence and chemical reactions in supersonic flames, and struggles to provide reliable quantitative assessments, especially in extreme conditions such as anoxic environments. In contrast, experimental measurements can directly obtain actual reignition response data of combustion residues under aerobic and anoxic conditions, providing a high-confidence verification benchmark for numerical simulations and serving as an effective means of assessing the degree of exhaust plume reignition. Summary of the Invention

[0004] To address the shortcomings of existing research methods on the reignition effect of rocket engine exhaust flames, which rely solely on numerical simulations and cannot verify their reliability through experimental measurements, this invention provides a testing and evaluation device and method for the reignition effect of rocket engine exhaust flames.

[0005] This invention is achieved using the following technical solution: A test and evaluation device for the reignition effect of rocket engine exhaust flame includes a low-pressure simulation chamber system, a temperature control system, an oxygen-free environment control system, and a measurement system.

[0006] Furthermore, the low-pressure simulation chamber system includes a low-pressure chamber body, a vacuum pump group, a vacuum gauge, an intake proportional valve, a small intake wind tunnel, a pressure regulating controller, an exhaust pipeline, an intake pipeline, and an exhaust switching valve; The small air-breathing wind tunnel is located inside the low-pressure chamber; The vacuum pump assembly is located outside the low-pressure chamber; The first end of the extraction pipeline is connected to the outlet of a small suction wind tunnel, and the second end is connected to the inlet of a vacuum pump unit. The intake proportional valve is installed on the extraction pipeline; The exhaust switching valve is a three-way valve, with its inlet connected to the outlet of the vacuum pump unit, its first outlet connected to the first end of the intake pipe, and its second outlet connected to the outside atmosphere. The second end of the air intake pipe is connected to the air intake of a small air-breathing wind tunnel; The vacuum gauge is installed on the pressure measuring port of the wall panel of the low-pressure chamber via a flange, and its probe is located inside the low-pressure chamber. The pressure regulating controller is located outside the low-pressure chamber. Its signal input terminal is electrically connected to the signal output terminal of the vacuum gauge via a shielded cable. The control output terminal of the pressure regulating controller is electrically connected to the speed control terminal of the vacuum pump group, the control terminal of the intake proportional valve, and the control terminal of the exhaust switching valve.

[0007] Furthermore, the temperature control system includes a temperature sampler, a cooling coil, an electric heater, a return air duct, and a temperature regulating controller; The return air duct is installed on the air intake duct, with its inlet end connected to the first outlet of the exhaust switching valve and its outlet end connected to the air intake of the small intake wind tunnel. The return air duct is located inside the low-pressure chamber. The refrigeration coil and electric heater are fixed to the inner cavity of the return air duct by a thermally conductive insulating bracket; The refrigeration coil is led out from the inside of the return air duct, passes through the duct wall of the return air duct and the duct wall of the low-pressure compartment in sequence, and is connected to the external refrigeration unit through a sealing flange; The temperature sampler is fixed to the top of the low-pressure chamber, and its probe is located inside the low-pressure chamber. The temperature control controller is located outside the low-pressure chamber. Its signal input terminal is electrically connected to the signal output terminal of the temperature sampler via a compensating wire, and its control output terminal is electrically connected to the electrodes of the electric heater and the regulating valve of the external refrigeration unit, respectively.

[0008] Furthermore, the oxygen-free environment control system includes a liquid nitrogen source, a nitrogen inlet valve, a nitrogen inlet controller, and an atomizing nozzle; The liquid nitrogen source is located outside the low-pressure chamber. The atomizing nozzle is located inside the low-pressure chamber; The inlet of the nitrogen inlet valve is connected to the liquid nitrogen source through an insulated cryogenic hose, and its outlet passes through the wall of the low-pressure chamber and is connected to the atomizing nozzle. The nitrogen intake controller is located outside the low-pressure chamber, and its control output terminal is electrically connected to the coil of the nitrogen intake valve via a signal line.

[0009] Furthermore, the measurement system includes a spectrometer, a thermal imager, a high-speed camera, and a measurement system synchronization controller; The spectrometer, thermal imager, and high-speed camera are all mounted on optical rails outside the low-pressure chamber, and the lenses of all three are aimed at the observation windows opened on the side wall of the low-pressure chamber. The synchronization signal output terminal of the synchronization controller of the measurement system is electrically connected to the trigger signal input terminals of the spectrometer, thermal imager, and high-speed camera, respectively.

[0010] A test and evaluation device for the reignition effect of rocket engine exhaust flame also includes: The cabin air inlet valve is installed on the air inlet pipe of the low-pressure cabin. The hull exhaust valve is installed on the exhaust port pipe of the low-pressure hull.

[0011] Furthermore, the spectrometer has a measurement wavelength range of 0.9-1.7 μm and 2-5 μm, and a spectral resolution of 1-4 cm⁻¹. -1 The thermal imager measures in the 3-5 μm band at a frequency of 256 Hz.

[0012] A method for testing and evaluating the reignition effect of rocket engine exhaust plume, employing a testing and evaluation device for the reignition effect of rocket engine exhaust plume as described in this invention, includes the following steps: Step 1: By controlling the air intake valve of the cabin, external airflow is introduced into the low-pressure cabin, while the target values ​​of the pressure regulating controller and temperature regulating controller are set, and the small air intake wind tunnel is turned on. Step 2: Start the vacuum pump unit and switch the exhaust switching valve to the state where the first outlet is connected to the inlet pipeline. Adjust the opening of the inlet proportional valve through the pressure regulating controller and control the refrigerant flow of the cooling coil and the heating power of the electric heater through the temperature regulating controller until the feedback values ​​of the vacuum gauge and temperature sampler reach the set target values. Step 3: Ignite and start the rocket engine located inside the low-pressure chamber; Step 4: Trigger the spectrometer, thermal imager, and high-speed camera through the measurement system synchronous controller to measure the infrared radiation intensity of the exhaust flame under aerobic conditions; Step 5: Shut down the rocket engine and close the cabin air intake valve; Step 6: Switch the exhaust switching valve to the state where the second outlet is connected to the outside atmosphere, start the vacuum pump group, and extract the gas in the low-pressure chamber to the outside atmosphere through the evacuation pipeline until the feedback value of the vacuum gauge is lower than the preset pressure threshold, then turn off the vacuum pump group. Step 7: Open the nitrogen inlet valve through the nitrogen inlet controller to spray liquid nitrogen into the low-pressure chamber through the atomizing nozzle. At the same time, switch the exhaust switching valve to the state where the first outlet is connected to the inlet pipeline. Start the vacuum pump group, adjust the opening of the inlet proportional valve through the pressure regulating controller, and adjust the heating power of the electric heater through the temperature regulating controller until the feedback values ​​of the temperature sampler and the vacuum gauge reach the target values ​​set in Step 1. Then close the nitrogen inlet valve and shut down the vacuum pump group. Step 8: Ignite and start the rocket engine; Step 9: Trigger the spectrometer, thermal imager, and high-speed camera through the measurement system synchronous controller to measure the infrared radiation intensity of the exhaust flame in an oxygen-free environment; Step 10: Compare the measurement results under aerobic and anaerobic conditions to assess the reignition effect.

[0013] This invention provides a testing and evaluation device and method for the reignition effect of rocket engine exhaust plume, which has the following advantages compared with the prior art: 1. Controllable cost and high repeatability: By replacing high-altitude simulation test with a ground low-pressure simulation chamber system, the test cost is greatly reduced, the test cycle is shortened, and the test can be repeated multiple times to meet the needs of rapid iterative design.

[0014] 2. Capable of acquiring exhaust flame radiation data under anaerobic conditions: The anaerobic environment is precisely established in the chamber through the anaerobic environment control system (liquid nitrogen vaporization to replace oxygen), and the first comparative test between aerobic and anaerobic conditions is realized. This allows for the separate evaluation of the impact of reignition effect on infrared radiation intensity, filling the gap in existing experimental methods that cannot obtain anaerobic data.

[0015] 3. It can provide reliable comparative test data: Through real-time pressure and temperature closed-loop control, the environmental parameters inside the engine compartment are kept stable during engine operation. Combined with synchronous measurement by multiple devices, comparative data of exhaust infrared radiation under aerobic and anaerobic environments are obtained, providing experimental basis for analyzing the impact of reignition effect and helping to reduce the dependence on numerical simulation models. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the device structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the method flow of the present invention.

[0018] In the diagram: 1. Low-pressure chamber; 2. Vacuum pump unit; 3. Vacuum gauge; 4. Inlet proportional valve; 5. Small air-suction wind tunnel; 6. Pressure regulator; 7. Temperature sampler; 8. Refrigeration coil; 9. Electric heater; 10. Return air duct; 11. Temperature regulator; 12. Liquid nitrogen source; 13. Nitrogen inlet valve; 14. Nitrogen inlet controller; 15. Liquid nitrogen via atomizing nozzle; 16. Rocket engine; 17. Observation window; 18. Spectrometer; 19. Thermal imager; 20. High-speed camera; 21. Measurement system synchronization controller; 22. Chamber inlet valve; 23. Chamber exhaust valve. Detailed Implementation

[0019] The present invention will be further explained and described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0020] A test and evaluation device for the reignition effect of rocket engine exhaust plume, such as... Figure 1 As shown, it includes a low-pressure simulation chamber system, a temperature control system, an oxygen-free environment control system, and a measurement system.

[0021] The low-pressure simulation chamber system includes a low-pressure chamber body 1, a vacuum pump group 2, a vacuum gauge 3, an intake proportional valve 4, a small suction wind tunnel 5, a pressure regulating controller 6, an extraction pipeline, an intake pipeline, and an exhaust switching valve.

[0022] The low-pressure chamber 1 serves as a sealed container for the simulation experiment, housing the rocket engine 16 and simulating low-pressure environments at different altitudes. A small air-breathing wind tunnel 5 is located inside the low-pressure chamber 1 to generate a stable and continuous low-pressure airflow, ensuring gas circulation within the chamber and thus guaranteeing temperature uniformity and pressure stability. The vacuum pump assembly 2 is located outside the low-pressure chamber 1, serving the dual purpose of evacuating and depressurizing the air while driving gas circulation.

[0023] The first end of the extraction pipeline connects to the outlet of the small suction wind tunnel 5, and the second end connects to the inlet of the vacuum pump unit 2. An intake proportional valve 4 is installed on the extraction pipeline to adjust the extraction flow rate, precisely controlling the pressure inside the low-pressure chamber 1 in conjunction with the vacuum pump unit 2. The exhaust switching valve is a three-way valve; its inlet connects to the outlet of the vacuum pump unit 2, its first outlet connects to the first end of the intake pipeline, and its second outlet connects to the external atmosphere. The second end of the intake pipeline connects to the inlet of the small suction wind tunnel 5. By switching the operating state of the exhaust switching valve, a closed-loop circulation mode (first outlet connected) or an external exhaust mode (second outlet connected) can be achieved.

[0024] Vacuum gauge 3 is mounted on the pressure measuring port of the wall panel of the low-pressure chamber 1 via a flange. Its probe is located inside the low-pressure chamber 1 and is used to monitor the gas pressure value inside the chamber in real time. The electrical signal is transmitted to the signal input terminal of the pressure regulating controller 6 via a shielded cable. The pressure regulating controller 6 is located outside the low-pressure chamber 1. Its control output terminal is electrically connected to the speed control terminal of the vacuum pump group 2, the control terminal of the inlet proportional valve 4, and the control terminal of the exhaust switching valve, respectively. Based on the deviation between the pressure value fed back by vacuum gauge 3 and the preset target value, the speed of vacuum pump group 2, the opening degree of inlet proportional valve 4, and the state of exhaust switching valve are dynamically adjusted to achieve precise closed-loop control of the chamber pressure.

[0025] The temperature control system includes a temperature sampler 7, a cooling coil 8, an electric heater 9, a return air duct 10, and a temperature regulating controller 11.

[0026] The return air duct 10 is installed on the intake duct, with its inlet end connected to the first outlet of the exhaust switching valve and its outlet end connected to the intake of the small intake wind tunnel 5. The return air duct 10 is located inside the low-pressure chamber 1. As the core channel for temperature regulation, the return air duct 10's inner cavity is used to install heat exchange elements. The refrigeration coil 8 and the electric heater 9 are fixed to the inner cavity of the return air duct 10 by a thermally conductive insulating bracket. The refrigeration coil 8 extends from the inside of the return air duct 10, passes through the wall of the return air duct 10 and the wall of the low-pressure chamber 1, and is connected to an external refrigeration unit via a sealing flange. The refrigerant provided by the external refrigeration unit evaporates and releases cooling energy within the refrigeration coil 8. The electrodes of the electric heater 9 are led out to the outside of the low-pressure chamber 1 via low-temperature resistant vacuum-sealed terminals and are electrically connected to the control output of the temperature control controller 11, releasing heat by energizing.

[0027] Temperature sampler 7 is fixed to the top of the low-pressure chamber 1, with its probe located inside the chamber. It uses a thermocouple to monitor the gas temperature inside the chamber in real time and transmits the temperature signal to the signal input terminal of temperature controller 11 via a compensating wire. Temperature controller 11 is located outside the low-pressure chamber 1, and its control output terminal is electrically connected to the electrodes of electric heater 9 and the regulating valve of the external refrigeration unit, respectively. Based on the deviation between the temperature value fed back by temperature sampler 7 and the preset target value, temperature controller 11 controls the heating current of electric heater 9 via a solid-state relay and controls the refrigerant flow rate of refrigeration coil 8 via a regulating valve, thereby precisely regulating the temperature of the circulating airflow in return air duct 10 and stabilizing the temperature inside the test chamber within the preset range.

[0028] The oxygen-free environment control system includes a liquid nitrogen source 12, a nitrogen inlet valve 13, a nitrogen inlet controller 14, and an atomizing nozzle 15.

[0029] The liquid nitrogen source 12 is located outside the low-pressure chamber 1 and serves as a liquid nitrogen storage tank. The atomizing nozzle 15 is located inside the low-pressure chamber 1 and is installed on the recirculation inlet pipeline. The inlet of the nitrogen inlet valve 13 is connected to the liquid nitrogen source 12 via an insulated cryogenic hose, and its outlet passes through the chamber wall of the low-pressure chamber 1 and connects to the atomizing nozzle 15. The nitrogen inlet controller 14 is located outside the low-pressure chamber 1, and its control output is electrically connected to the coil of the nitrogen inlet valve 13 via a signal line.

[0030] When an oxygen-free environment needs to be established, the nitrogen intake controller 14 opens the nitrogen intake valve 13. Liquid nitrogen is delivered from the liquid nitrogen source 12 through the insulated hose and the nitrogen intake valve 13 to the atomizing nozzle 15. The atomizing nozzle 15 atomizes the liquid nitrogen and sprays it into the low-pressure chamber 1. The liquid nitrogen quickly vaporizes and replaces the oxygen in the chamber. At the same time, it can be used in conjunction with the vacuum pump group 2 and the exhaust switching valve to discharge oxygen-containing gas, achieving precise control of the gas composition in the chamber and creating an oxygen-free environment.

[0031] The measurement system includes a spectrometer 18, a thermal imager 19, a high-speed camera 20, and a measurement system synchronization controller 21.

[0032] The measurement system includes a spectrometer 18, a thermal imager 19, a high-speed camera 20, and a measurement system synchronization controller 21.

[0033] The spectrometer 18, thermal imager 19, and high-speed camera 20 are all mounted on optical rails outside the low-pressure chamber 1, and the lenses of all three are aimed at the observation window 17 opened on the side wall of the low-pressure chamber 1, with the center of the lens focused on the core region of the exhaust plume of the rocket engine 16. The spectrometer 18 measures in the 0.9-1.7 μm and 2-5 μm wavelength bands, with a spectral resolution of 1-4 cm⁻¹. -1 The thermal imager 19 is used to obtain the spectral radiation characteristics of the exhaust flame; the measurement band of the thermal imager 19 is 3-5 μm and the frequency is 256 Hz, which is used to obtain the infrared thermal image distribution of the exhaust flame; the high-speed camera 20 is used to record images of the combustion process of the exhaust flame.

[0034] The synchronization signal output terminal of the measurement system synchronization controller 21 is electrically connected to the trigger signal input terminals of the spectrometer 18, the thermal imager 19 and the high-speed camera 20, respectively. It can synchronously control the three measuring devices to start measuring at the same time, ensuring the time consistency of multi-source data and realizing the synchronous measurement of the infrared radiation of the tail flame.

[0035] The testing and evaluation device of the present invention further includes a cabin air inlet valve 22 and a cabin exhaust valve 23. The cabin air inlet valve 22 is installed on the air inlet pipe of the low-pressure cabin 1 and is used to introduce external airflow to establish an oxygenated environment; the cabin exhaust valve 23 is installed on the exhaust pipe of the low-pressure cabin 1 and is used to remove residual exhaust gas in the cabin after the test.

[0036] A method for testing and evaluating the reignition effect of rocket engine exhaust plume, employing a testing and evaluation device for the reignition effect of rocket engine exhaust plume as described in this invention, such as... Figure 2 As shown, it includes the following steps: Step 1: By controlling the air intake valve 22, external air is introduced into the low-pressure chamber 1. At the same time, the target values ​​of the pressure regulating controller 6 and the temperature regulating controller 11 are set (corresponding to the pressure and temperature at the simulated altitude), and the small air intake wind tunnel 5 is turned on, so that the air in the chamber forms a closed-loop circulation flow field through the return air pipe 10.

[0037] Step Two: Start the vacuum pump unit 2 and switch the exhaust switching valve to the state where the first outlet is connected to the intake pipe (closed-loop circulation mode). Adjust the opening of the intake proportional valve 4 via the pressure regulating controller 6 to control the airflow and gradually reduce the cabin pressure to the target value. Control the refrigerant flow of the cooling coil 8 and the heating power of the electric heater 9 via the temperature regulating controller 11 to regulate the temperature of the circulating airflow in the return air duct 10. The vacuum gauge 3 and temperature sampler 7 monitor the cabin pressure and temperature in real time and send the feedback values ​​to the pressure regulating controller 6 and temperature regulating controller 11, forming a closed-loop control until both pressure and temperature stabilize at the target values ​​set in Step One. At this point, the cabin is an oxygen-rich environment (air composition), and the pressure and temperature simulate atmospheric conditions at a specific altitude.

[0038] Step 3: Ignite and start the rocket engine 16 located inside the low-pressure chamber 1. The rocket engine 16 begins to work, and its exhaust flame is ejected, which reignites with the ambient air.

[0039] Step 4: The spectrometer 18, thermal imager 19, and high-speed camera 20 are triggered by the synchronous controller 21 of the measurement system to simultaneously measure the infrared radiation intensity of the exhaust flame under aerobic conditions, including spectral radiation characteristics, thermal image distribution, and combustion process images. During the measurement process, the vacuum gauge 3 and temperature sampler 7 continuously monitor the pressure and temperature inside the chamber, and the pressure regulating controller 6 and temperature regulating controller 11 adjust in real time to ensure that the environmental parameters inside the chamber remain unchanged at preset values.

[0040] Step 5: Shut down rocket engine 16 and close cabin air intake valve 22.

[0041] Step Six: Switch the exhaust switching valve to the state where the second outlet is connected to the outside atmosphere (external exhaust mode), start vacuum pump group 2, and extract the gas (including combustion exhaust gas) in the low-pressure chamber 1 to the outside atmosphere through the evacuation pipeline until the feedback value of vacuum gauge 3 is lower than the preset pressure threshold (close to vacuum state), and then turn off vacuum pump group 2. This step prepares for the subsequent establishment of an oxygen-free environment.

[0042] Step 7: Open the nitrogen inlet valve 13 via the nitrogen inlet controller 14, allowing liquid nitrogen from the liquid nitrogen source 12 to be injected into the low-pressure chamber 1 through the insulated pipeline and atomizing nozzle 15. The liquid nitrogen rapidly vaporizes and replaces residual oxygen. Simultaneously, switch the exhaust switching valve to connect the first outlet to the inlet pipeline, and start the vacuum pump group 2 to circulate the gas in a closed loop, promoting uniform distribution of the vaporized liquid nitrogen. Adjust the opening of the inlet proportional valve 4 via the pressure regulating controller 6 to maintain the chamber pressure; adjust the heating power of the electric heater 9 via the temperature regulating controller 11 to compensate for the drastic cooling caused by the vaporization of liquid nitrogen and prevent the temperature from becoming too low. Continue until the feedback values ​​from the temperature sampler 7 and the vacuum gauge 3 both reach the target values ​​set in Step 1 (simulating the pressure and temperature at altitude). At this point, the gas inside the chamber is mainly nitrogen, forming an oxygen-free environment. Then close the nitrogen inlet valve 13 and shut down the vacuum pump group 2.

[0043] Step 8: Ignite and start the rocket engine 16. At this time, the exhaust flame is emitted, and since there is no oxygen in the chamber, no reignition reaction occurs.

[0044] Step Nine: Trigger the spectrometer 18, thermal imager 19, and high-speed camera 20 simultaneously via the measurement system synchronization controller 21 to measure the infrared radiation intensity of the exhaust plume under oxygen-free conditions. Similarly, maintain stable pressure and temperature inside the chamber during the measurement process.

[0045] Step 10: Compare the infrared radiation intensity of the exhaust plume under aerobic and anaerobic environments, and analyze the differences. Since the reignition effect exists under aerobic conditions but not under anaerobic conditions, the difference in radiation intensity reflects the actual contribution of the reignition effect to the infrared radiation of the exhaust plume, thus achieving a quantitative assessment of the reignition effect.

[0046] Through the above steps, the present invention can simulate atmospheric parameters at different altitudes on the ground and measure the infrared radiation intensity of the exhaust plume under aerobic and anaerobic environments, thereby accurately assessing the impact of the reignition effect and solving the problems of high cost, inability to obtain anaerobic data, and uncertainty in numerical simulation of existing high-altitude simulation tests.

[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A testing and evaluation device for the reignition effect of rocket engine exhaust flame, characterized in that: It includes a low-pressure simulation chamber system, a temperature control system, an oxygen-free environment control system, and a measurement system.

2. The testing and evaluation device for the reignition effect of rocket engine exhaust flame according to claim 1, characterized in that, The low-pressure simulation chamber system includes a low-pressure chamber body (1), a vacuum pump group (2), a vacuum gauge (3), an intake proportional valve (4), a small suction wind tunnel (5), a pressure regulating controller (6), an exhaust pipeline, an intake pipeline, and an exhaust switching valve; The small air-breathing wind tunnel (5) is located inside the low-pressure chamber (1); The vacuum pump assembly (2) is located outside the low-pressure chamber (1); The first end of the exhaust pipe is connected to the outlet of the small suction wind tunnel (5), and the second end is connected to the inlet of the vacuum pump group (2). The intake proportional valve (4) is installed on the extraction pipeline; The exhaust switching valve is a three-way valve, whose inlet is connected to the outlet of the vacuum pump group (2), whose first outlet is connected to the first end of the inlet pipe, and whose second outlet is connected to the outside atmosphere. The second end of the air intake pipe is connected to the air intake of a small air-breathing wind tunnel (5); The vacuum gauge (3) is installed on the pressure measuring port of the wall panel of the low-pressure chamber (1) through a flange, and its probe is located inside the low-pressure chamber (1); The pressure regulating controller (6) is located outside the low-pressure chamber (1). Its signal input terminal is electrically connected to the signal output terminal of the vacuum gauge (3) via a shielded cable. The control output terminal of the pressure regulating controller (6) is electrically connected to the speed control terminal of the vacuum pump group (2), the control terminal of the intake proportional valve (4), and the control terminal of the exhaust switching valve.

3. The testing and evaluation device for the reignition effect of rocket engine exhaust flame according to claim 2, characterized in that, The temperature control system includes a temperature sampler (7), a cooling coil (8), an electric heater (9), a return air duct (10), and a temperature regulating controller (11). The return air duct (10) is installed on the air intake duct, its inlet end is connected to the first outlet of the exhaust switching valve, its outlet end is connected to the air intake of the small air intake wind tunnel (5), and the return air duct (10) is located inside the low pressure chamber (1). The refrigeration coil (8) and the electric heater (9) are fixed to the inner cavity of the return air duct (10) by a thermally conductive insulating bracket; The refrigeration coil (8) is led out from the inside of the return air duct (10), passes through the pipe wall of the return air duct (10) and the chamber wall of the low-pressure compartment (1) in sequence, and is connected to the external refrigeration unit through a sealing flange; The temperature sampler (7) is fixed to the top of the low-pressure chamber (1), and its probe is located inside the low-pressure chamber (1). The temperature control controller (11) is located outside the low-pressure chamber (1). Its signal input terminal is electrically connected to the signal output terminal of the temperature sampler (7) through a compensation wire, and its control output terminal is electrically connected to the electrode of the electric heater (9) and the regulating valve of the external refrigeration unit, respectively.

4. The testing and evaluation device for the reignition effect of rocket engine exhaust flame according to claim 3, characterized in that, The oxygen-free environment control system includes a liquid nitrogen source (12), a nitrogen inlet valve (13), a nitrogen inlet controller (14), and an atomizing nozzle (15). The liquid nitrogen source (12) is located outside the low-pressure chamber (1); The atomizing nozzle (15) is located inside the low-pressure chamber (1); The inlet of the nitrogen inlet valve (13) is connected to the liquid nitrogen source (12) through an insulated cryogenic hose, and its outlet passes through the wall of the low-pressure chamber (1) and is connected to the atomizing nozzle (15). The nitrogen intake controller (14) is located outside the low-pressure chamber (1), and its control output terminal is electrically connected to the coil of the nitrogen intake valve (13) via a signal line.

5. The testing and evaluation device for the reignition effect of rocket engine exhaust flame according to claim 4, characterized in that, The measurement system includes a spectrometer (18), a thermal imager (19), a high-speed camera (20), and a measurement system synchronization controller (21). The spectrometer (18), thermal imager (19) and high-speed camera (20) are all mounted on optical rails outside the low-pressure chamber (1), and the lenses of the three are all aimed at the observation window (17) opened on the side wall of the low-pressure chamber (1). The synchronization signal output terminal of the synchronization controller (21) of the measurement system is electrically connected to the trigger signal input terminals of the spectrometer (18), the thermal imager (19), and the high-speed camera (20), respectively.

6. The testing and evaluation device for the reignition effect of rocket engine exhaust flame according to claim 5, characterized in that, Also includes: The cabin air inlet valve (22) is installed on the air inlet pipe of the low-pressure cabin (1); The hull exhaust valve (23) is installed on the exhaust port pipe of the low-pressure hull (1).

7. The testing and evaluation device for the reignition effect of rocket engine exhaust flame according to claim 6, characterized in that, The spectrometer (18) has a measurement wavelength range of 0.9-1.7 μm and 2-5 μm, and a spectral resolution of 1-4 cm⁻¹. -1 The thermal imager (19) measures in the 3-5 μm band and has a frequency of 256 Hz.

8. A method for testing and evaluating the reignition effect of rocket engine exhaust plume, characterized in that, The test and evaluation device for the reignition effect of rocket engine exhaust flame as described in claim 7 includes the following steps: Step 1: By controlling the cabin air intake valve (22), external airflow is introduced into the low-pressure cabin (1), while setting the target values ​​of the pressure regulating controller (6) and the temperature regulating controller (11), and opening the small air intake wind tunnel (5). Step 2: Start the vacuum pump group (2) and switch the exhaust switching valve to the state where the first outlet is connected to the inlet pipeline. Adjust the opening of the inlet proportional valve (4) through the pressure regulating controller (6), and control the refrigerant flow of the cooling coil (8) and the heating power of the electric heater (9) through the temperature regulating controller (11) until the feedback values ​​of the vacuum gauge (3) and the temperature sampler (7) reach the set target values. Step 3: Ignite and start the rocket engine (16) located inside the low-pressure chamber (1). Step 4: Trigger the spectrometer (18), thermal imager (19) and high-speed camera (20) through the measurement system synchronous controller (21) to measure the infrared radiation intensity of the exhaust flame under aerobic conditions; Step 5: Shut down the rocket engine (16) and close the cabin air intake valve (22); Step 6: Switch the exhaust switching valve to the state where the second outlet is connected to the outside atmosphere, start the vacuum pump group (2), and extract the gas in the low-pressure chamber (1) to the outside atmosphere through the extraction pipeline until the feedback value of the vacuum gauge (3) is lower than the preset pressure threshold, then turn off the vacuum pump group (2). Step 7: Open the nitrogen inlet valve (13) through the nitrogen inlet controller (14) to spray liquid nitrogen into the low-pressure chamber (1) through the atomizing nozzle (15). At the same time, switch the exhaust switching valve to the state where the first outlet is connected to the inlet pipeline. Start the vacuum pump group (2), adjust the opening of the inlet proportional valve (4) through the pressure regulating controller (6), and adjust the heating power of the electric heater (9) through the temperature regulating controller (11) until the feedback values ​​of the temperature sampler (7) and the vacuum gauge (3) reach the target values ​​set in Step 1. Then close the nitrogen inlet valve (13) and shut down the vacuum pump group (2). Step 8: Ignite and start the rocket engine (16); Step 9: Trigger the spectrometer (18), thermal imager (19) and high-speed camera (20) through the measurement system synchronous controller (21) to measure the infrared radiation intensity of the exhaust flame under oxygen-free environment; Step 10: Compare the measurement results under aerobic and anaerobic conditions to assess the reignition effect.

Images