A thermal radiation simulation system based on thermochemical combustion

Abstract

The purpose of the present invention is to solve the technical problems of the existing thermal radiation simulation system such as small thermal radiation loading area and low heat flux intensity, and to establish a thermal radiation simulation system based on thermochemical combustion. The system includes a control unit and an execution unit. The control unit is used to send action instructions to the execution unit and monitor the execution status of the execution unit. The execution unit includes an input unit, a mixing unit and an output unit connected in sequence. The input unit includes a gas input unit and a solid storage device, wherein aluminum powder is loaded in the solid storage device; the gas input unit includes an oxygen input device and a nitrogen input device arranged in parallel. Nitrogen, oxygen and aluminum powder are mixed in the mixing unit to form a gas-solid mixture, and enter the output unit. After thermochemical combustion, a thermal radiation field is formed in the output unit.

Description

Technical Field

[0001] The invention relates to a thermal radiation simulation system, in particular to a thermal radiation simulation system based on thermochemical combustion. Background Art

[0002] In response to the thermal radiation environment requirements of re-entry capsules, hypersonic aircraft, explosions, fires and other environments, different thermal radiation simulation devices can be used to simulate the thermal radiation environment, such as arc heaters, gas flow test devices, infrared quartz lamp radiation heating devices, etc.

[0003] The arc heater uses high-pressure linear arc discharge to heat air or nitrogen. The heated high-temperature airflow first enters the mixing temperature and pressure chamber, then expands and accelerates through the supersonic Laval nozzle. The aerodynamic heating test is performed on the model fixed at the nozzle outlet. The aerodynamic heating system generally uses the arc wind tunnel mode. The heating system mainly consists of an arc heater, nozzle, test section, model support system, diffuser, cooler and vacuum system. The advantages of the arc heater are a good spectral range and high maximum intensity (up to 600W / cm 2 Disadvantages include a small uniform irradiation area, the generation of large amounts of ultraviolet radiation, and the emission of gases harmful to the human body. They also consume significant power (most arc heaters exceed 40MW), are unstable, require complex maintenance, and have a short lifespan. Furthermore, high-power, high-voltage arc heaters often suffer from increased physical coupling under high-voltage conditions, poor arc stability, enhanced arc bypass breakdown, shortened electrode life, arc root instability, and poor thermal management of arc root motion.

[0004] The gas flow test facility primarily consists of a gas heater, an energy supply system, a measurement and control system, a test piece, and a feed mechanism. Its operating principle is that oxidizer and fuel combust in a combustion chamber to generate high-temperature, high-pressure gas. This gas is accelerated through a nozzle to form a high-temperature supersonic gas flow, which enters the test section within the test chamber for thermal evaluation of the test piece. Currently, gas flow test facilities include free jet gas flow test equipment and gas flow wind tunnel systems. The free jet type is capable of conducting material-level and ablation performance tests, as well as section-level local ablation thermal structural tests. The 200MW gas flow supersonic wind tunnel test system, built by the Beijing Aerospace Long March Aircraft Research Institute, is primarily used for thermal structure and thermal matching tests of heat-resistant test pieces. It operates at a total temperature of 3650K, has a nozzle exit diameter of up to 1.5m, and can run for up to 1000s. However, this device is not suitable for combined sequential loading with shock waves, nor is it suitable for measuring material and thermal radiation effect parameters. Therefore, it cannot perform thermal radiation tests on large structural components or prototype equipment measuring tens of square meters.

[0005] Infrared quartz lamp radiation heating is a method based on the principle of halide regeneration cycle. The U.S. Air Force Weapons Laboratory (AFWL) has built a thermal radiation effect simulation system using tungsten filament quartz lamps, arranging them into an array (i.e., increasing the uniform irradiation area). Under certain operating modes, it can approach a 4000K blackbody output, and the switching device can adjust the waveform. Wu Dafang and others from the Beijing University of Aeronautics and Astronautics independently developed a device that can achieve an extremely fast nonlinear heating rate of up to 210℃ / s and generate up to 2MW / m 2 A quartz lamp infrared radiation aerodynamic thermal environment test simulation system was developed to simulate the transient nonlinear heat flux density and achieve an ultra-high temperature oxidizing thermal environment of 1500°C; however, the thermal radiation loading heat flux intensity of the device was low, the loading area was small, and the heat flux uniformity and repeatability could not be guaranteed. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problems of the existing thermal radiation simulation system such as small thermal radiation loading area and low heat flux intensity, and to establish a thermal radiation simulation system based on thermochemical combustion.

[0007] In order to achieve the above objectives, the technical solutions provided by the present invention are as follows:

[0008] A thermal radiation simulation system based on thermochemical combustion is characterized in that it comprises a control unit and an execution unit connected to the control unit; the control unit is used to send action instructions to the execution unit and monitor the execution status of the execution unit;

[0009] The execution unit includes an input unit, a mixing unit and an output unit connected in sequence;

[0010] The input unit includes a gas input unit and a solid storage device, wherein the solid storage device is loaded with aluminum powder;

[0011] The gas input unit includes an oxygen input device and a nitrogen input device arranged in parallel, wherein the output end of the nitrogen input device is divided into two paths, one of which is connected to the input end of the solid storage device;

[0012] The other output end of the nitrogen input device, the output end of the oxygen input device, and the output end of the solid storage device are respectively connected to the input end of the mixing unit; the nitrogen in the nitrogen input device, the oxygen in the oxygen input device, and the aluminum powder respectively enter the mixing unit and form a gas-solid mixture; the output end of the mixing unit is connected to the output unit, and the gas-solid mixture undergoes thermochemical combustion in the output unit and forms a thermal radiation field at the output end of the output unit.

[0013] Furthermore, a pressure display device and a pressure relief device are provided on the solid storage device, and a weighing device is provided at the bottom; the pressure display device and the pressure relief device are respectively connected to the control unit, the pressure display device is used to monitor the pressure of the nitrogen entering the solid storage device, and the pressure relief device is used to maintain the balance of the nitrogen pressure in the solid storage device; the weighing device is used to measure the weight of the aluminum powder output by the solid storage device to ensure that the weight of the aluminum powder meets the test requirements.

[0014] Furthermore, a pneumatic ball valve and / or an electric regulating valve is provided between the weighing device and the solid storage device for adjusting the output of the aluminum powder.

[0015] Furthermore, a plurality of evenly distributed ignition devices are installed in the output unit, and the ignition devices are electrically connected to the control unit. When the control unit sends an ignition command, each ignition device is turned on synchronously to cause the gas-solid mixture to burn, thereby ensuring the uniformity of ignition and combustion, thereby optimizing the uniformity of the thermal radiation field.

[0016] Furthermore, the oxygen input device includes a liquid oxygen storage device and a first vaporizer. The liquid oxygen output by the liquid oxygen storage device is converted into oxygen by the first vaporizer and then enters the mixing unit. The nitrogen input device includes a liquid nitrogen storage device and a second vaporizer. The liquid nitrogen output by the liquid nitrogen storage device is converted into nitrogen by the second vaporizer, one of which enters the solid storage device and the other enters the mixing unit.

[0017] Furthermore, a first control valve assembly is provided on the pipeline between the first vaporization device and the mixing unit, and a second control valve assembly is provided on the pipeline between the second vaporization device and the mixing unit. The first control valve assembly and the second control valve assembly are respectively electrically connected to the control unit for controlling the pressure and flow of the gas in the pipeline.

[0018] Furthermore, the first control valve assembly includes a pressure transmitter, a solenoid shut-off valve, an electric regulating valve and a flow control valve which are sequentially arranged on the pipeline between the first vaporizing device and the mixing unit;

[0019] The second control valve assembly includes a pressure transmitter, a solenoid shut-off valve, an electric regulating valve and a flow control valve which are sequentially arranged on the pipeline between the second vaporizing device and the mixing unit;

[0020] The pressure transmitter, electromagnetic shut-off valve, electric regulating valve and flow control valve are electrically connected to the control unit respectively.

[0021] Furthermore, a check valve is provided on the pipeline between the first vaporization device and the mixing unit to prevent oxygen backflow, and the check valve is electrically connected to the control unit.

[0022] Furthermore, alarm devices are respectively provided between the liquid oxygen storage device and the first vaporization device, between the first vaporization device and the mixing unit, between the solid storage device and the mixing unit, and at the output end of the output unit. The alarm devices are electrically connected to the control unit and are used to transmit abnormal information to the control unit in an emergency, so that the control unit cuts off the corresponding control valve to ensure the safety of system operation.

[0023] Furthermore, the control unit is a PLC controller, which has a remote control function. The PLC controller can remotely operate the control valves on each gas channel, send ignition commands, and trigger the simulation system.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The simulation system of the present invention includes a control unit and an execution unit. The control unit is used to send action instructions to the execution unit and monitor the execution status of the execution unit. The execution unit includes an input unit, a mixing unit and an output unit connected in sequence. The input unit includes a gas input unit and a solid storage device, wherein the solid storage device is loaded with aluminum powder; the gas input unit includes an oxygen input device and a nitrogen input device arranged in parallel. Nitrogen, oxygen and aluminum powder are mixed in the mixing unit to form a gas-solid mixture, and enter the output unit. After thermochemical combustion, a thermal radiation field is formed in the output unit. The overall structure of this system is relatively compact and the overall safety is high, and it can provide a uniform thermal radiation field. At the same time, the use of thermochemical combustion can continuously generate heat flow and continuously output it through the output unit, thereby increasing the heat flow loading area and heat flow output intensity of the system.

[0026] 2. The solid storage device of the present invention is provided with a pressure display device and a weighing device, which can accurately weigh the output aluminum powder according to the weight requirement of the aluminum powder in each test by using the weighing device in combination with a pneumatic ball valve and / or an electric regulating valve, thereby improving the sufficiency of the thermochemical reaction.

[0027] 3. The simulation system of the present invention has nitrogen and oxygen transport channels, and is provided with a first control valve assembly and a second control valve assembly. By controlling the pressure and flow of the gas in the pipeline, nitrogen and oxygen are stably transported to the mixing unit. At the same time, a check valve is also provided on the pipeline between the first vaporization device and the mixing unit to prevent oxygen backflow, thereby improving the safety of the system.

[0028] 4. The output unit of the present invention is equipped with multiple evenly distributed ignition devices to ensure the uniformity of ignition and the uniformity of combustion of nitrogen, oxygen and aluminum powder, thereby optimizing the uniformity of the heat radiation field.

[0029] 5. The simulation system of the present invention is provided with alarm devices between the liquid oxygen storage device and the first vaporization device, between the first vaporization device and the mixing unit, between the solid storage device and the mixing unit, and at the output end of the output unit, respectively, for transmitting abnormal information to the control unit in an emergency, and the control unit controls and cuts off the corresponding control valve to ensure the safety of system operation.

[0030] 6. The control unit of the present invention is a PLC controller, which has a remote control function. It can remotely operate the control valves on each gas channel, send ignition commands and trigger the simulation system, making the operation more convenient and safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of an embodiment of a thermal radiation simulation system based on thermochemical combustion according to the present invention;

[0032] Figure 2 This is a waveform diagram of heat flux intensity actually measured in a thermal radiation field experiment in an embodiment of the thermal radiation simulation system based on thermochemical combustion of the present invention.

[0033] The reference numerals are as follows:

[0034] 1-control unit, 2-input unit, 21-solid storage device, 22-oxygen input device, 221-liquid oxygen storage device, 222-first vaporization device, 223-first control valve assembly, 23-nitrogen input device, 231-liquid nitrogen storage device, 232-second vaporization device, 233-second control valve assembly, 3-mixing unit, 4-output unit, 5-alarm device. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings and specific embodiments.

[0036] like Figure 1 As shown, the purpose of the present invention is to establish a thermal radiation simulation system based on thermochemical combustion, which is mainly used to evaluate the thermal radiation effects of target materials and structures. The system includes a control unit 1 and an execution unit connected to the control unit 1; wherein the control unit 1 is mainly used to send action instructions to the execution unit and monitor the execution status of the execution unit. In this embodiment, the control unit 1 is a PLC controller, which has a remote control function. The PLC controller can remotely operate the control valves on each gas channel, send ignition commands, and trigger the simulation system. It also has a reactant input parameter detection and numerical display function, which can display the input parameters and combustion progress in real time.

[0037] The execution unit comprises an input unit 2, a mixing unit 3, and an output unit 4, which are connected in sequence. The input unit 2 includes a gas input unit and a solid storage device 21. The solid storage device 21 contains aluminum powder, the solid raw material required for combustion. This invention is primarily based on the heat transfer between aluminum powder and oxygen, where aluminum powder offers the best overall performance, including cost and heat release. In actual operation, the appropriate solid raw material can be selected for the combustion reaction based on specific needs and budget considerations. In this embodiment, a weighing device is provided at the bottom outlet of the solid storage device 21. This device is used to measure the weight of the aluminum powder output from the solid storage device 21. The weighing device can be used to adjust the weight of the aluminum powder based on the weight required for each test. Furthermore, in this embodiment, a pneumatic ball valve and / or an electric regulating valve are provided between the weighing device and the solid storage device 21. These valves are also electrically connected to the control unit 1 and are specifically adjusted by the control unit 1 to precisely adjust the output of the aluminum powder to achieve quantitative testing.

[0038] The gas input unit includes a large-capacity oxygen input device 22 and a nitrogen input device 23 arranged in parallel. The oxygen input device 22 includes a liquid oxygen storage device 221 and a first vaporization device 222. Liquid oxygen is converted into oxygen through the first vaporization device 222 and then enters the mixing unit 3. A check valve is also provided on the pipeline between the first vaporization device 222 and the mixing unit 3 to prevent the backflow of oxygen. The check valve is electrically connected to the control unit 1 and its switch is controlled by the control unit 1, thereby improving the safety of the system.

[0039] The nitrogen input device 23 includes a large-capacity liquid nitrogen storage device 231 and a second vaporization device 232. After the liquid nitrogen is converted into nitrogen gas by the second vaporization device 232, one path of the nitrogen gas enters the solid storage device 21 through a pipeline, providing driving pressure for the transportation of aluminum powder. The solid storage device 21 is provided with a pressure display device, which is electrically connected to the control unit 1 and is used to monitor the pressure of the nitrogen entering the solid storage device 21 to ensure that the pressure of the nitrogen in the solid storage device 21 meets the design requirements. To improve safety, the solid storage device 21 is also provided with a pressure relief device, which is electrically connected to the control unit 1. If the nitrogen pressure in the solid storage device 21 is too high, the pressure relief device can be controlled by the control unit 1 to achieve balance of the nitrogen pressure in the solid storage device 21.

[0040] At the same time, a flow control valve is provided between the second vaporization device 232 and the solid storage device 21, which is used to adjust the flow of nitrogen entering the solid storage device 21, so as to quickly and safely transport the aluminum powder in the solid storage device 21 to the mixing unit 3, forming a suspended aluminum powder cloud with a certain turbulence intensity and uniform macroscopic spatial distribution.

[0041] Another stream of nitrogen enters the mixing unit 3 through a pipeline. Nitrogen in the nitrogen input device 23, oxygen in the oxygen input device 22, and aluminum powder in the solid storage device 21 enter the mixing unit 3 through pipelines respectively, and are mixed uniformly in the mixing unit 3 to form a gas-solid mixture.

[0042] The output end of the mixing unit 3 is connected to the output unit 4. The gas-solid mixture forms a gas-solid mixed cloud field in the output unit 4, and undergoes thermochemical combustion to form a thermal radiation field. The radiation field is formed based on thermochemical combustion. As long as the raw materials required for combustion are sufficient, a continuous heat flow supply can be achieved, thereby having a higher heat flow radiation intensity; at the same time, the output unit 4 can also adjust the transport share of the heat flow, thereby increasing the area of ​​heat flow loading and improving the assessment range.

[0043] To improve combustion efficiency and the uniformity of heat flux in the thermal radiation field, this embodiment incorporates multiple, evenly distributed ignition devices within output unit 4, electrically connected to control unit 1. These ignition devices utilize high-voltage plasma ignition. Control unit 1 issues an ignition command, and each ignition device ignites synchronously, causing the gas-solid mixture cloud field to combust, thereby generating the thermal radiation field required for the assessment. Multiple, evenly distributed ignition devices ensure uniform ignition and combustion, thereby optimizing the uniformity of the thermal radiation field.

[0044] To further control the combustion process, this embodiment includes a first control valve assembly 223 on the pipeline between the first vaporizer 222 and the mixing unit 3, and a second control valve assembly 233 on the pipeline between the second vaporizer 232 and the mixing unit 3. The first and second control valve assemblies 223 and 233 are identical, comprising a pressure transmitter, a solenoid shut-off valve, an electric regulating valve, and a flow control valve, respectively, disposed on the pipelines between the first vaporizer 222 and the mixing unit 3 and between the second vaporizer 232 and the mixing unit 3, respectively. These components precisely control the pressure and flow of gas within the pipelines. Alternatively, corresponding regulating or control valves may be installed as needed. In this embodiment, the pressure transmitter, solenoid shut-off valve, electric regulating valve, and flow control valve are each electrically connected to the control unit 1, providing real-time feedback on changes in gas pressure, flow, and other data within the transport channel. The control unit 1 manipulates the opening and closing of each valve to achieve precise control of the combustion process.

[0045] To improve the efficiency of emergency response, this embodiment includes alarm devices 5 between the liquid oxygen storage device 221 and the first vaporizer 222, between the first vaporizer 222 and the mixing unit 3, between the solid storage device 21 and the mixing unit 3, and at the output end of the output unit 4. These devices are electrically connected to the control unit 1 and are used to transmit abnormality information to the control unit 1 in an emergency. The control unit 1 then controls the opening and closing of the corresponding valves, thereby preventing accidents and improving system safety. Furthermore, the alarm information can be queried on the control unit 1, and the corresponding treatment measures are displayed, providing guidance for subsequent testing.

[0046] Combine Figure 2 The output unit of the thermal radiation simulation system of the present invention is equipped with three independent injection structures. The injection structures are 20 cm apart. The length of the nozzle in the injection structure is 30 cm, which can form a rectangular thermal radiation field of 1.5 m × 4 m. An electric high-voltage ignition gun is placed 20 cm above the nozzle for ignition. The oxygen flow rate is 50-60 N.m 2 / h, pressure 30-40kPa, valve opening 100%; nitrogen 35-40N.m 2 / h, valve opening 20%; aluminum powder single 2.8-3kg, valve opening 16-18%, with the two-dimensional thermal radiation field jet outlet line as the X-axis, the center line as the Y-axis, the coordinates of the six heat flux sensors are (0, 50), (0, 100), (0, 150), (50, 100), (-50, 100), (50, 50), that is, the distance between the coordinate point 0 of the jet outlet center is 50 or 100 cm, which can achieve a uniform heat flux intensity of 0.6MW / m 2 , action time is adjustable from 1 to 20 seconds, and it is more applicable.

[0047] The thermal radiation simulation system of the present invention can be used to assess thermal radiation effects with high heat flux intensity, over a large area, and for a long time. It utilizes high-voltage electric ignition to solve the problem that micron-sized aluminum powder particles are difficult to ignite. At the same time, it is combined with a remote PLC controller to achieve sequential ignition and optimize the uniformity of the thermal radiation field.

[0048] Although the embodiments of the present invention have been shown and described above, it will be apparent to those skilled in the art that any changes or modifications to the above embodiments should fall within the scope of protection of the present invention as long as they are within the spirit of the present invention.

Claims

1. A thermal radiation simulation system based on thermochemical combustion, characterized by: It comprises a control unit (1) and an execution unit connected to the control unit (1); the control unit (1) is used to send action instructions to the execution unit and monitor the execution status of the execution unit; The execution unit comprises an input unit (2), a mixing unit (3) and an output unit (4) connected in sequence; The input unit (2) includes a gas input unit and a solid storage device (21), wherein aluminum powder is loaded in the solid storage device (21); a pressure display device and a pressure relief device are provided on the solid storage device (21), and a weighing device is provided at the bottom; the pressure display device and the pressure relief device are electrically connected to the control unit (1) respectively, the pressure display device is used to monitor the pressure of nitrogen entering the solid storage device (21), and the pressure relief device is used to maintain the balance of the nitrogen pressure in the solid storage device (21); the weighing device is used to measure the weight of the aluminum powder output by the solid storage device (21); The gas input unit comprises an oxygen input device (22) and a nitrogen input device (23) arranged in parallel, wherein the output end of the nitrogen input device (23) is divided into two paths, one of which is connected to the input end of the solid storage device (21); The other output end of the nitrogen input device (23), the output end of the oxygen input device (22), and the output end of the solid storage device (21) are respectively connected to the input end of the mixing unit (3); the nitrogen in the nitrogen input device (23), the oxygen in the oxygen input device (22), and the aluminum powder respectively enter the mixing unit (3) and form a gas-solid mixture; The oxygen input device (22) includes a liquid oxygen storage device (221) and a first vaporizing device (222). The liquid oxygen output from the liquid oxygen storage device (221) is converted into oxygen by the first vaporizing device (222) and then enters the mixing unit (3). The nitrogen input device (23) includes a liquid nitrogen storage device (231) and a second vaporization device (232). After the liquid nitrogen output from the liquid nitrogen storage device (231) is converted into nitrogen by the second vaporization device (232), one path of the nitrogen enters the solid storage device (21) and the other path enters the mixing unit (3); The output end of the mixing unit (3) is connected to the output unit (4), and the gas-solid mixture undergoes thermochemical combustion in the output unit (4) and forms a thermal radiation field at the output end of the output unit (4).

2. The thermal radiation simulation system based on thermochemical combustion according to claim 1, characterized in that: A pneumatic ball valve and / or an electric regulating valve is also provided between the weighing device and the solid storage device (21) for regulating the output of the aluminum powder.

3. The thermal radiation simulation system based on thermochemical combustion according to claim 1 or 2, characterized in that: A plurality of evenly distributed ignition devices are installed in the output unit (4), and the ignition devices are electrically connected to the control unit (1).

4. The thermal radiation simulation system based on thermochemical combustion according to claim 3, characterized in that: A first control valve assembly (223) is provided on the pipeline between the first vaporizing device (222) and the mixing unit (3), and a second control valve assembly (233) is provided on the pipeline between the second vaporizing device (232) and the mixing unit (3); the first control valve assembly (223) and the second control valve assembly (233) are respectively electrically connected to the control unit (1) for controlling the pressure and flow of the gas in the pipeline.

5. The thermal radiation simulation system based on thermochemical combustion according to claim 4, characterized in that: The first control valve assembly (223) comprises a pressure transmitter, an electromagnetic shut-off valve, an electric regulating valve and a flow control valve which are sequentially arranged on a pipeline between the first vaporizing device (222) and the mixing unit (3); The second control valve assembly (233) comprises a pressure transmitter, a solenoid shut-off valve, an electric regulating valve and a flow control valve which are sequentially arranged on a pipeline between the second vaporizing device (232) and the mixing unit (3); The pressure transmitter, electromagnetic shut-off valve, electric regulating valve and flow control valve are electrically connected to the control unit (1) respectively.

6. The thermal radiation simulation system based on thermochemical combustion according to claim 5, characterized in that: A check valve is also provided on the pipeline between the first vaporizing device (222) and the mixing unit (3) to prevent oxygen backflow, and the check valve is electrically connected to the control unit (1).

7. The thermal radiation simulation system based on thermochemical combustion according to claim 6, characterized in that: An alarm device (5) is provided between the liquid oxygen storage device (221) and the first vaporizing device (222), between the first vaporizing device (222) and the mixing unit (3), between the solid storage device (21) and the mixing unit (3), and at the output end of the output unit (4). The alarm device (5) is electrically connected to the control unit (1) and is used to transmit abnormal information to the control unit (1) and issue an alarm.

8. The thermal radiation simulation system based on thermochemical combustion according to claim 7, characterized in that: The control unit (1) is a PLC controller.

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