Flow field low NOx control device of three-phase alternating current arc heater

Abstract

The invention discloses a flow field low-NOx control device for a three-phase alternating-current arc heater. The flow field low-NOx control device comprises a three-phase alternating-current arc wind tunnel system, an airflow total temperature control system and a NOx concentration control system. Wherein the three-phase alternating current arc wind tunnel system is respectively connected with the airflow total temperature control system and the NOx concentration control system; and the NOx concentration control system is connected with the airflow total temperature control system. The flow field NOx concentration is accurately controlled, the flow field quality of the arc heater in an aerodynamic force test is improved, and the adverse effect of NOx components on the test is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of AC arc heaters, and in particular relates to a flow field low NOx control device for a three-phase AC arc heater. Background Art

[0002] In the field of aerospace aerodynamic heating, AC arc heaters are an important type of heater. They use industrial frequency AC power to generate AC arcs to heat the airflow, thereby providing high enthalpy and high-pressure airflow, playing an important role in material ablation protection, structural thermal sealing, etc.

[0003] As the Mach number of conventional hypersonic wind tunnel airflow continues to increase, traditional kerosene heating, heat storage plate heating and other forms cannot meet the heating needs of large gas flows. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide a three-phase AC arc heater flow field low NOx control device, which realizes the precise control of the NOx concentration in the flow field, improves the flow field quality of the arc heater in the aerodynamic test, and reduces the adverse effects of the NOx components on the test.

[0005] The object of the present invention is achieved through the following technical scheme: a three-phase AC arc heater flow field low NOx control device, comprising: a three-phase AC arc wind tunnel system, an airflow total temperature control system and a NOx concentration control system; wherein the three-phase AC arc wind tunnel system is respectively connected to the airflow total temperature control system and the NOx concentration control system; the NOx concentration control system is connected to the airflow total temperature control system.

[0006] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the three-phase AC arc wind tunnel system is used to generate a nitrogen-oxygen mixed gas flow; the total gas flow temperature control system monitors the temperature of the nitrogen-oxygen mixed gas flow in real time, adjusts the ratio of primary nitrogen to secondary nitrogen, and achieves that the temperature of the nitrogen-oxygen mixed gas flow is not higher than the reaction temperature of nitrogen oxide production; the NOx concentration control system monitors the NOx concentration of the nozzle outlet gas flow in the arc wind tunnel of the three-phase AC arc wind tunnel system in real time.

[0007] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the three-phase AC arc wind tunnel system includes a three-phase AC arc heater, an air supply device, an AC power supply, a water supply device, an arc wind tunnel and a vacuum system; wherein the three-phase AC arc heater is respectively connected to the air supply device, the AC power supply, the water supply device and the arc wind tunnel; and the arc wind tunnel is connected to the vacuum system.

[0008] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the three-phase AC arc heater includes a heater arm air inlet ring, a nitrogen air inlet chamber and an oxygen air inlet chamber; wherein the heater arm air inlet ring, the nitrogen air inlet chamber and the oxygen air inlet chamber are connected in sequence; the oxygen air inlet chamber is connected to the arc wind tunnel; and the air supply device is respectively connected to the heater arm air inlet ring, the nitrogen air inlet chamber and the oxygen air inlet chamber.

[0009] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the power supply provides industrial frequency high-voltage AC power to the three-phase AC arc heater; the water supply device provides high-pressure cooling water to the three-phase AC arc heater; the primary nitrogen provided by the gas supply device enters the heater arm intake ring, the secondary nitrogen provided by the gas supply device enters the nitrogen intake chamber, and the oxygen provided by the gas supply device enters the oxygen intake chamber; the heater heats the primary nitrogen entering the heater arm intake ring, the heated primary nitrogen enters the nitrogen intake chamber, the secondary nitrogen is mixed with the heated primary nitrogen to obtain nitrogen in a molecular state at a lower temperature, the nitrogen in a molecular state at a lower temperature enters the oxygen intake chamber, the nitrogen in a molecular state at a lower temperature is mixed with oxygen to obtain a nitrogen-oxygen mixed gas flow, and the nitrogen-oxygen mixed gas flow enters the vacuum system through the arc wind tunnel.

[0010] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the total airflow temperature control system includes a temperature collector, a temperature signal processor, a central control system and an air supply controller; wherein, the temperature collector: collects the nitrogen-oxygen mixed airflow temperature signal in real time, and inputs the nitrogen-oxygen mixed airflow temperature signal into the temperature signal processor; the temperature signal processor: receives the nitrogen-oxygen mixed airflow temperature signal, processes the nitrogen-oxygen mixed airflow temperature signal to obtain a processed temperature signal, and transmits the processed temperature signal to the central control system; the central control system: when it detects that the processed temperature signal is higher than the reaction temperature of nitrogen oxide production, sends a command signal to the air supply controller; the air supply controller: receives the command signal, and controls the air supply device to adjust the ratio of primary nitrogen to secondary nitrogen according to the command signal to ensure that the temperature of the nitrogen-oxygen mixed airflow is always not higher than the reaction temperature of NOx production.

[0011] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the NOx concentration control system includes an absorption spectrum system; wherein the absorption spectrum system emits a measuring laser, and the measuring laser passes through the nitrogen-oxygen mixed flow to obtain the NOx concentration in the nitrogen-oxygen mixed flow.

[0012] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the absorption spectrum system includes a signal generator, a laser controller, a laser generator, a photoelectric detector and a photoelectric signal processor; wherein, the signal generator: sends a signal to the laser controller; the laser controller: receives the signal and controls the laser generator to emit a measuring laser after receiving the signal, passing through the nitrogen-oxygen mixed airflow in the arc wind tunnel; the photoelectric detector: collects the nitrogen-oxygen mixed airflow and transmits it to the photoelectric signal processor; the photoelectric signal processor: obtains the NOx concentration in the nitrogen-oxygen mixed airflow according to the nitrogen-oxygen mixed airflow, and transmits the NOx concentration in the nitrogen-oxygen mixed airflow to the central control system.

[0013] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the central control system: determines the NOx concentration in the nitrogen and oxygen mixed flow and the concentration value required for the aerodynamic test flow field. If the NOx concentration in the nitrogen and oxygen mixed flow is higher than the concentration value required for the aerodynamic test flow field, a second command signal is sent to the air supply controller.

[0014] In the above-mentioned three-phase AC arc heater flow field low NOx control device, the gas supply controller receives a second command signal and controls the gas supply device to adjust the ratio of primary nitrogen to secondary nitrogen according to the second command signal, so as to achieve a preset value of flow field NOx concentration.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The total airflow temperature control system of the present invention monitors the temperature of the nitrogen-oxygen mixed airflow in real time and adjusts the ratio of primary nitrogen to secondary nitrogen to ensure that the temperature of the nitrogen-oxygen mixed airflow is not higher than the reaction temperature of nitrogen oxides (NOx). The phased entry of primary nitrogen, secondary nitrogen and oxygen not only effectively reduces the generation of nitrogen oxides (NOx), but also simulates the airflow components of conventional hypersonic wind tunnels, avoiding the interference of arc heating to the aerodynamic flow field;

[0017] (2) The NOx concentration control system of the present invention monitors the NOx concentration of the nozzle outlet airflow in the arc wind tunnel in real time through the absorption spectrum system, and further adjusts the ratio of primary nitrogen to secondary nitrogen. The two-level regulation of the airflow total temperature control system and the NOx concentration control system realizes the precise control of the NOx concentration in the flow field, improves the flow field quality of the arc heater in the aerodynamic test, and reduces the adverse effects of NOx components on the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0019] Figure 1 It is a structural diagram of a three-phase AC arc heater flow field low NOx control device provided by an embodiment of the present invention;

[0020] Figure 2 is a composition diagram of a three-phase AC arc wind tunnel system provided by an embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the air inlet position of a three-phase AC arc heater provided in an embodiment of the present invention;

[0022] Figure 4 It is a composition diagram of the airflow total temperature control system provided by an embodiment of the present invention;

[0023] Figure 5 It is a composition diagram of the NOx concentration control system provided by an embodiment of the present invention;

[0024] Figure 6 It is a composition diagram of the absorption spectrum system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] Figure 1 1 is a structural diagram of a three-phase AC arc heater flow field low NOx control device provided by an embodiment of the present invention. Figure 1 As shown, the three-phase AC arc heater flow field low NOx control device includes: a three-phase AC arc wind tunnel system, an airflow total temperature control system and a NOx concentration control system; wherein the three-phase AC arc wind tunnel system is respectively connected to the airflow total temperature control system and the NOx concentration control system; the NOx concentration control system is connected to the airflow total temperature control system.

[0027] The three-phase AC arc wind tunnel system is used to generate a nitrogen-oxygen mixed gas flow; the total gas flow temperature control system monitors the temperature of the nitrogen-oxygen mixed gas flow in real time, adjusts the ratio of primary nitrogen to secondary nitrogen, and ensures that the temperature of the nitrogen-oxygen mixed gas flow is not higher than the reaction temperature for the production of nitrogen oxides; the NOx concentration control system monitors the NOx concentration of the air flow at the nozzle outlet in the arc wind tunnel of the three-phase AC arc wind tunnel system in real time.

[0028] The AC arc heater heats the primary nitrogen entering the intake rings of the three heater arms. The secondary nitrogen enters through the nitrogen intake chamber and mixes with the primary nitrogen. Oxygen enters through the oxygen intake chamber and is mixed with the incoming nitrogen again. The mass ratio of oxygen to nitrogen is strictly controlled according to the air composition.

[0029] The total airflow temperature control system monitors the temperature of the nitrogen-oxygen mixed airflow in real time and adjusts the ratio of primary nitrogen to secondary nitrogen to ensure that the temperature of the nitrogen-oxygen mixed airflow is no higher than the reaction temperature of nitrogen oxides (NOx) production.

[0030] The NOx concentration control system monitors the NOx concentration of the nozzle outlet airflow in the arc wind tunnel in real time through the absorption spectrum system, and further adjusts the ratio of primary nitrogen to secondary nitrogen, thereby achieving quantitative control of the NOx concentration in the flow field.

[0031] The two-level regulation of the total airflow temperature control system and the NOx concentration control system realizes the precise control of the NOx concentration in the flow field, improves the flow field quality of the arc heater in the aerodynamic test, and reduces the adverse effects of NOx components on the test.

[0032] The staged entry of primary nitrogen, secondary nitrogen and oxygen not only effectively reduces the generation of nitrogen oxides (NOx), but also simulates the air flow components of conventional hypersonic wind tunnels, avoiding the interference of arc heating to the aerodynamic flow field.

[0033] like Figure 2 As shown, the three-phase AC arc wind tunnel system includes a three-phase AC arc heater 11, an air supply device 12, an AC power supply 13, a water supply device 14, an arc wind tunnel 15 and a vacuum system 16; wherein the three-phase AC arc heater 11 is connected to the air supply device 12, the AC power supply 13, the water supply device 14 and the arc wind tunnel 15 respectively; the arc wind tunnel 15 is connected to the vacuum system 16.

[0034] like Figure 3As shown, the three-phase AC arc heater 11 includes a heater arm air inlet ring 111, a nitrogen air inlet chamber 112 and an oxygen air inlet chamber 113; wherein the heater arm air inlet ring 111, the nitrogen air inlet chamber 112 and the oxygen air inlet chamber 113 are connected in sequence; the oxygen air inlet chamber 113 is connected to the arc wind tunnel 15; and the air supply device 12 is respectively connected to the heater arm air inlet ring 111, the nitrogen air inlet chamber 112 and the oxygen air inlet chamber 113.

[0035] The power supply 13 provides industrial frequency high-voltage AC power to the three-phase AC arc heater 11; the water supply device 14 provides high-pressure cooling water to the three-phase AC arc heater 11; the primary nitrogen provided by the gas supply device 12 enters the heater arm air inlet ring 111, the secondary nitrogen provided by the gas supply device 12 enters the nitrogen air inlet chamber 112, and the oxygen provided by the gas supply device 12 enters the oxygen air inlet chamber 113; the heater heats the primary nitrogen entering the heater arm air inlet ring 111, the heated primary nitrogen enters the nitrogen air inlet chamber 112, the secondary nitrogen is mixed with the heated primary nitrogen to obtain nitrogen in a molecular state at a lower temperature, the nitrogen in a molecular state at a lower temperature enters the oxygen air inlet chamber 113, the nitrogen in a molecular state at a lower temperature is mixed with oxygen to obtain a nitrogen-oxygen mixed gas flow, and the nitrogen-oxygen mixed gas flow enters the vacuum system 16 through the arc wind tunnel 15.

[0036] like Figure 4 As shown, the total temperature control system of the airflow includes a temperature collector 21, a temperature signal processor 22, a central control system 23 and an air supply controller 24; wherein, the temperature collector 21: collects the temperature signal of the nitrogen-oxygen mixed airflow in real time, and inputs the temperature signal of the nitrogen-oxygen mixed airflow into the temperature signal processor 22; the temperature signal processor 22: receives the temperature signal of the nitrogen-oxygen mixed airflow, processes the temperature signal of the nitrogen-oxygen mixed airflow to obtain a processed temperature signal, and transmits the processed temperature signal to the central control system 23; the central control system 23: when it is detected that the processed temperature signal is higher than the reaction temperature of nitrogen oxide production, a command signal is sent to the air supply controller 24; the air supply controller 24: receives the command signal, and controls the air supply device 12 to adjust the ratio of primary nitrogen to secondary nitrogen according to the command signal, so as to ensure that the temperature of the nitrogen-oxygen mixed airflow is always not higher than the reaction temperature of NOx production.

[0037] like Figure 5 As shown, the NOx concentration control system includes an absorption spectrum system 31; wherein the absorption spectrum system 31 emits a measuring laser, and the measuring laser passes through the nitrogen-oxygen mixed flow to obtain the NOx concentration in the nitrogen-oxygen mixed flow.

[0038] like Figure 6As shown, the absorption spectrum system 31 includes a signal generator 311, a laser controller 312, a laser generator 313, a photoelectric detector 314 and a photoelectric signal processor 315; wherein, the signal generator 311: sends a signal to the laser controller 312; the laser controller 312: receives the signal and controls the laser generator 313 to send a measuring laser after receiving the signal, passing through the nitrogen-oxygen mixed airflow in the arc wind tunnel 15; the photoelectric detector 314: collects the nitrogen-oxygen mixed airflow and transmits it to the photoelectric signal processor 315; the photoelectric signal processor 315: obtains the NOx concentration in the nitrogen-oxygen mixed airflow according to the nitrogen-oxygen mixed airflow, and transmits the NOx concentration in the nitrogen-oxygen mixed airflow to the central control system 23. The central control system 23: determines the size of the NOx concentration in the nitrogen-oxygen mixed airflow and the concentration value required by the aerodynamic test flow field, and sends a second command signal to the air supply controller 24 if the NOx concentration in the nitrogen-oxygen mixed airflow is higher than the concentration value required by the aerodynamic test flow field. The gas supply controller 24 receives the second command signal, and controls the gas supply device 12 to adjust the ratio of the primary nitrogen to the secondary nitrogen according to the second command signal, so as to achieve a preset NOx concentration in the flow field.

[0039] The three-phase AC arc heater 11 heats the primary nitrogen entering the three heater arm intake rings 111 when the gas supply device 12 provides high-pressure gas, the AC power supply 13 provides industrial frequency high-voltage AC power, and the water supply device 14 provides high-pressure cooling water. The heated nitrogen is in a plasma state with a relatively high temperature. The secondary nitrogen enters through the nitrogen intake chamber 112 and mixes with the high-temperature primary nitrogen. The air flow temperature drops rapidly, and the nitrogen plasma recombine into a molecular state. Oxygen enters through the oxygen intake chamber 113 and mixes with the nitrogen in a molecular state with a relatively low temperature. The mass ratio of oxygen to nitrogen is strictly controlled according to the air composition. The supersonic airflow formed by the nitrogen-oxygen mixture passes through the arc wind tunnel 15 and finally enters the vacuum system 16.

[0040] The total airflow temperature control system 2 collects the temperature signal of the nitrogen-oxygen mixed airflow in real time through the temperature collector 21, and inputs the collected temperature signal into the temperature signal processor 22. The processed temperature signal enters the central control system 23. When the measured nitrogen-oxygen mixed airflow is higher than the reaction temperature of nitrogen oxides (NOx), a signal is sent to the air supply controller 24, which then controls the air supply device to adjust the ratio of primary nitrogen to secondary nitrogen, ensuring that the temperature of the nitrogen-oxygen mixed airflow is always no higher than the reaction temperature of NOx.

[0041] The NOx concentration control system 3 sends a signal through the signal generator 311 in the absorption spectrum system 31. After receiving the signal, the laser controller 312 controls the laser generator 313 to send out a measuring laser, which passes through the nitrogen-oxygen supersonic airflow in the arc wind tunnel 15, is collected by the photoelectric detector 314, and is processed by the photoelectric signal processor 315, and enters the central control system to obtain the NOx concentration in the nitrogen-oxygen supersonic airflow. If the NOx concentration is higher than the concentration value required by the aerodynamic test flow field, the central control system sends a signal to the air supply control device, and then controls the air supply device to further adjust the intake ratio of primary nitrogen and secondary nitrogen, thereby realizing quantitative control of the NOx concentration in the flow field.

[0042] The two-level regulation of the total airflow temperature control system 2 and the NOx concentration control system 3 realizes the precise control of the NOx concentration in the flow field, improves the flow field quality of the arc heater in the aerodynamic test, and reduces the adverse effects of the NOx component on the test. The phased entry of primary nitrogen, secondary nitrogen and oxygen not only effectively reduces the generation of nitrogen oxides (NOx), but also simulates the air flow components of conventional hypersonic wind tunnels, avoiding the interference of arc heating on the aerodynamic flow field.

[0043] In this embodiment, the total temperature control system of the airflow monitors the temperature of the nitrogen-oxygen mixed airflow in real time, adjusts the ratio of primary nitrogen to secondary nitrogen, and realizes that the temperature of the nitrogen-oxygen mixed airflow is not higher than the reaction temperature of nitrogen oxides (NOx). The phased entry of primary nitrogen, secondary nitrogen and oxygen not only effectively reduces the generation of nitrogen oxides (NOx), but also simulates the air flow components of conventional hypersonic wind tunnels, avoiding the interference of arc heating to the aerodynamic flow field; in this embodiment, the NOx concentration control system monitors the NOx concentration of the nozzle outlet airflow in the arc wind tunnel in real time through the absorption spectrum system, and further adjusts the ratio of primary nitrogen to secondary nitrogen. The two-level regulation of the total temperature control system of the airflow and the NOx concentration control system realizes the precise control of the NOx concentration of the flow field, improves the flow field quality of the arc heater in the aerodynamic test, and reduces the adverse effects of the NOx component on the test.

[0044] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A three-phase AC arc heater flow field low NOx control device, characterized in that include: Three-phase AC arc wind tunnel system, airflow total temperature control system and NOx concentration control system; among them, The three-phase AC arc wind tunnel system is connected to the airflow total temperature control system and the NOx concentration control system respectively; The NOx concentration control system is connected to the airflow total temperature control system.

2. The three-phase AC arc heater flow field low NOx control device according to claim 1, characterized in that: The three-phase AC arc wind tunnel system is used to generate a nitrogen-oxygen mixed gas flow; The airflow total temperature control system monitors the temperature of the nitrogen-oxygen mixed airflow in real time, and adjusts the ratio of primary nitrogen to secondary nitrogen to ensure that the temperature of the nitrogen-oxygen mixed airflow is not higher than the reaction temperature of nitrogen oxide production; The NOx concentration control system monitors the NOx concentration of the nozzle outlet airflow in the arc wind tunnel of the three-phase AC arc wind tunnel system in real time.

3. The three-phase AC arc heater flow field low NOx control device according to claim 1, characterized in that: The three-phase AC arc wind tunnel system comprises a three-phase AC arc heater (11), an air supply device (12), an AC power supply (13), a water supply device (14), an arc wind tunnel (15) and a vacuum system (16); wherein: The three-phase AC arc heater (11) is respectively connected to the air supply device (12), the AC power supply (13), the water supply device (14) and the arc wind tunnel (15); The arc wind tunnel (15) is connected to the vacuum system (16).

4. The three-phase AC arc heater flow field low NOx control device according to claim 3, characterized in that: The three-phase AC arc heater (11) comprises a heater arm air inlet ring (111), a nitrogen air inlet chamber (112) and an oxygen air inlet chamber (113); wherein: The heater arm air inlet ring (111), the nitrogen air inlet chamber (112) and the oxygen air inlet chamber (113) are connected in sequence; The oxygen inlet chamber (113) is connected to the arc wind tunnel (15); The gas supply device (12) is respectively connected to the heater arm air inlet ring (111), the nitrogen air inlet chamber (112) and the oxygen air inlet chamber (113).

5. The three-phase AC arc heater flow field low NOx control device according to claim 4, characterized in that: The power supply (13) provides industrial frequency high voltage AC power to the three-phase AC arc heater (11); The water supply device (14) provides high-pressure cooling water to the three-phase AC arc heater (11); The primary nitrogen provided by the gas supply device (12) enters the heater arm air inlet ring (111), the secondary nitrogen provided by the gas supply device (12) enters the nitrogen air inlet chamber (112), and the oxygen provided by the gas supply device (12) enters the oxygen air inlet chamber (113); The heater heats the primary nitrogen gas entering through the heater arm intake ring (111), and the heated primary nitrogen gas enters the nitrogen intake chamber (112). The secondary nitrogen gas is mixed with the heated primary nitrogen gas to obtain nitrogen gas in a molecular state at a lower temperature. The nitrogen gas in a molecular state at a lower temperature enters the oxygen intake chamber (113), and the nitrogen gas in a molecular state at a lower temperature is mixed with oxygen to obtain a nitrogen-oxygen mixed gas flow. The nitrogen-oxygen mixed gas flow enters the vacuum system (16) through the arc wind tunnel (15).

6. The three-phase AC arc heater flow field low NOx control device according to claim 3, characterized in that: The airflow total temperature control system comprises a temperature collector (21), a temperature signal processor (22), a central control system (23) and an air supply controller (24); wherein: The temperature collector (21) collects the temperature signal of the nitrogen-oxygen mixed airflow in real time, and inputs the temperature signal of the nitrogen-oxygen mixed airflow into the temperature signal processor (22). The temperature signal processor (22) receives the temperature signal of the nitrogen-oxygen mixed airflow, processes the temperature signal of the nitrogen-oxygen mixed airflow to obtain a processed temperature signal, and transmits the processed temperature signal to the central control system (23); The central control system (23) sends a command signal to the air supply controller (24) when it detects that the processed temperature signal is higher than the reaction temperature of nitrogen oxide generation; The gas supply controller (24) receives the command signal and controls the gas supply device (12) to adjust the ratio of the primary nitrogen gas to the secondary nitrogen gas according to the command signal, so as to ensure that the temperature of the nitrogen-oxygen mixed gas flow is always not higher than the reaction temperature of NOx generation.

7. The three-phase AC arc heater flow field low NOx control device according to claim 3, characterized in that: The NOx concentration control system comprises an absorption spectrum system (31); wherein, The absorption spectrum system (31) emits a measuring laser, which passes through the nitrogen-oxygen mixed gas flow to obtain the NOx concentration in the nitrogen-oxygen mixed gas flow.

8. The three-phase AC arc heater flow field low NOx control device according to claim 7, characterized in that: The absorption spectrum system (31) comprises a signal generator (311), a laser controller (312), a laser generator (313), a photoelectric detector (314) and a photoelectric signal processor (315); wherein: The signal generator (311) sends a signal to the laser controller (312); The laser controller (312) receives the signal and controls the laser generator (313) to emit a measuring laser to pass through the nitrogen-oxygen mixed airflow in the arc wind tunnel (15); The photoelectric detector (314) collects the nitrogen-oxygen mixed gas flow and transmits it to the photoelectric signal processor (315); The photoelectric signal processor (315) obtains the NOx concentration in the nitrogen-oxygen mixed airflow according to the nitrogen-oxygen mixed airflow, and transmits the NOx concentration in the nitrogen-oxygen mixed airflow to the central control system (23).

9. The three-phase AC arc heater flow field low NOx control device according to claim 8, characterized in that: The central control system (23) determines the difference between the NOx concentration in the nitrogen-oxygen mixed airflow and the concentration value required for the aerodynamic test flow field, and sends a second command signal to the air supply controller (24) if the NOx concentration in the nitrogen-oxygen mixed airflow is higher than the concentration value required for the aerodynamic test flow field.

10. The three-phase AC arc heater flow field low NOx control device according to claim 9, characterized in that: The gas supply controller (24) receives a second command signal and controls the gas supply device (12) to adjust the ratio of primary nitrogen to secondary nitrogen according to the second command signal, thereby achieving a flow field NOx concentration reaching a preset value.

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