System for slowing down plasma sheath

Abstract

The utility model discloses a system for slowing down a plasma sheath, which comprises a pressure sensor arranged at the foremost end of a shock tube, and further comprises a delay synchronous machine connected with the pressure sensor through an optical fiber I; the spraying device is connected with the delay synchronous machine through an optical fiber II; wherein the spraying device comprises a circuit module connected with the delay synchronous machine; and the water passing electromagnetic valve module is electrically connected with the circuit module so as to switch the on-off state of the medium in the liquid storage tank and the reserved small hole in the aircraft model. The system for slowing down the plasma sheath provided by the utility model has the characteristic of short valve opening time, so that the system is suitable for related fields such as research on plasma shock waves and the like; meanwhile, in a plasma shock tunnel experiment, the spraying device can realize liquid spraying and flow control, and is of great significance to research on slowing down or eliminating the plasma sheath.

Description

Technical Field

[0001] This invention relates to the field of ground-based plasma shock tunnel testing. More specifically, this invention relates to a system for mitigating plasma sheathing. Background Technology

[0002] In the aerospace field, when a spacecraft is traveling at hypersonic speeds, the surrounding atmospheric density changes drastically, creating a powerful shock wave at its leading edge. This shock wave, combined with the high-speed airflow and intense friction between the spacecraft's surface and the shock wave, causes a rapid increase in the surrounding air temperature. This ionizes the atmosphere and the spacecraft's surface, covering them with a layer of high-temperature plasma known as a plasma sheath (or blackout). Currently, plasma sheaths are unavoidable; any spacecraft entering the atmosphere of any planet will encounter a plasma sheath, and the sheath formed during atmospheric reentry can also cause radio signal interruptions. To address this issue, ground-based plasma shock wave wind tunnel tests have attempted to mitigate the plasma sheath by spraying water near it, but a dedicated spraying system for this purpose does not yet exist. While existing technologies disclose related ejection devices, such as a method for mitigating blackout communication in high-speed aircraft (patent application number 202110716664.8), which discloses a storage device and an ejection device within the aircraft, the storage device storing carbon dioxide and the ejection device ejecting carbon dioxide; when communication between the aircraft and the ground is interrupted, the ejection device is activated, and the carbon dioxide stored in the storage device is ejected outside the aircraft, with the direction of the ejected carbon dioxide forming an acute angle with the direction of the plasma flow field; the CO2 reacts to ultimately generate neutral oxygen atoms, thereby reducing the electron density around the aircraft, the structure of the ejection device is not described. Furthermore, the following problems exist in ground-based plasma shock tunnel experiments:

[0003] First, in shock tunnel experiments, the generated shock waves have a high velocity, and the control time required from the generation of the trigger signal to the opening of the water solenoid valve is extremely demanding. Second, plasma shock tunnel experiments need to be repeated, so the stability of the device must be good. However, in the existing technology, there is no disclosed spraying system specifically designed to mitigate plasma sheath experiments, which can be directly adapted to ground-based plasma shock tunnel experiments to ensure that it can quickly open the water solenoid valve and complete the water spraying operation while maintaining stability. Utility Model Content

[0004] One object of this invention is to solve the above-mentioned problems and / or defects, and to provide the advantages that will be described later.

[0005] To achieve these objectives and other advantages of this invention, a system for mitigating plasma sheathing is provided, including a pressure sensor disposed at the foremost tip of the shock tube, and further comprising:

[0006] A time-delay synchronizing machine connected to a pressure sensor via fiber optic cable I;

[0007] Spraying device connected to a delay synchronizer via fiber optic II;

[0008] The spraying device includes:

[0009] The circuit module connected to the time delay synchronizer;

[0010] A water-passing solenoid valve module electrically connected to the circuit module to switch the on / off state of the medium in the storage tank and the reserved small hole on the aircraft model.

[0011] Preferably, the circuit module is configured to include:

[0012] Thyristors connected to the time delay synchronizer;

[0013] A switch is installed between the thyristor and the water-passing solenoid valve module;

[0014] A DC power supply for powering thyristors;

[0015] A resistor connected in parallel with the water solenoid valve in the water solenoid valve module;

[0016] The DC power supply, switch, thyristor, and resistor are all integrated on the PVC board.

[0017] Preferably, the water-passing solenoid valve module is configured to include:

[0018] The gas supply pipeline connecting the liquid storage tank to the external driving gas source, and ball valve I installed on the gas supply pipeline;

[0019] A water-passing solenoid valve that connects the liquid storage tank to a pre-drilled hole on the aircraft model via a water supply pipeline;

[0020] Among them, a ball valve II is also provided between the water-passing solenoid valve and the reserved small hole on the aircraft model;

[0021] A pressure gauge is also installed on the connection branch between ball valve I and the liquid storage tank.

[0022] Preferably, a pressure reducing valve is also provided between the driving air source and ball valve I.

[0023] Preferably, the water-passing solenoid valve is a two-way control valve.

[0024] Preferably, the PVC board is provided with multiple grooves adapted to the external structure of the DC power supply, switch, and thyristor;

[0025] Each settling tank has a flexible layer at its inner edge;

[0026] The PVC panels are provided with mounting holes in pairs at positions that mate with each settling tank.

[0027] This invention offers at least the following advantages: Firstly, the shock wave pressure is acquired immediately via a pressure sensor. Using the pressure sensor signal as a time reference, a pulse signal generated by a delay synchronizing machine drives the water-passing solenoid valve module, opening the valve approximately 30ms later. This design eliminates the need for manual triggering; simply supplying DC power and receiving the signal from the pressure sensor at the front of the shock tube immediately triggers the water-passing solenoid valve module to operate. The short valve opening time makes it suitable for research in plasma shock waves and related fields. Secondly, in plasma shock wave wind tunnel experiments, the spraying device in this invention enables liquid spraying and flow control, which is significant for studying the mitigation or elimination of plasma shock wave effects.

[0028] Furthermore, the present invention divides the spraying device into two modules: a circuit module and a water solenoid valve module. Through modular design, interference from external equipment is reduced, and the stability of control is ensured.

[0029] Furthermore, compared with the prior art, the connection method between the delay synchronizing machine and the spraying device in this utility model is limited to optical fiber, which has the characteristics of fast transmission speed and strong anti-interference ability.

[0030] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the spraying device in one embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of a plasma mitigation sheath system in one embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the structure of the PVC board of this utility model. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0035] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0036] It should be noted that in the description of this utility model, the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In addition, the terms "I" and "II" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installed", "equipped with", "sleeved / connected", "connected", etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0038] Furthermore, in this utility model, unless otherwise explicitly specified and limited, the first feature being "on" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium.

[0039] Example 1

[0040] A system for mitigating plasma sheaths, the structure of which is as follows: Figure 1-2 As shown, it includes a pressure sensor 1 located at the front end of the shock tube, and also includes:

[0041] The time delay synchronizer 2, which is connected to the pressure sensor 1 via fiber optic cable I26, is typically an STC810 ​​model. The connection between the pressure sensor 1 and the time delay synchronizer 2 via fiber optic cable I26 ensures transmission speed and anti-interference capability.

[0042] The spraying device connected to the delay synchronizer 2 via fiber optic II3 has advantages such as fast transmission speed and strong anti-interference ability.

[0043] The spraying device includes:

[0044] Circuit module 4 is connected to the delay synchronizer 2;

[0045] Electrically connected to circuit module 4, the water-passing solenoid valve module 7 switches the on / off state of the medium in the storage tank 5 and the reserved small hole on the aircraft model 6.

[0046] As can be seen from the test data of the water-passing solenoid valve spraying device shown in Table 1, this scheme uses the signal of pressure sensor 1 as the time reference, and drives the water-passing solenoid valve module 7 through the pulse signal generated by the delay synchronizing machine 2. The valve opens after a delay of about 30ms, thereby achieving the time requirement for wind tunnel control from the generation of the trigger signal to the opening of the water-passing solenoid valve.

[0047] Table 1

[0048]

[0049] Working Principle: In practical applications, the spraying device typically uses water as the liquid. The water mixes with the sheath on the aircraft surface to reduce plasma density, thus slowing down or eliminating the plasma sheath. Specifically, a pressure sensor 1 is installed at the very front of the shock tube. When the shock wave passes through the pressure sensor 1, it generates a corresponding pressure signal. This pressure signal is used as a time reference. After a delay by the time delay synchronizer 2, the circuit module 4 controls the water-passing solenoid valve module 7 to open and remain in a normally open state. This allows water pre-reserved in the storage tank 5 to be injected into the aircraft model 6 under pressure and sprayed out from several small holes at the front of the aircraft model 6, thereby slowing down or eliminating the plasma sheath. When the circuit module 4 is disconnected, the water-passing solenoid valve module 7 closes, directly interrupting the spraying.

[0050] Example 2

[0051] This second embodiment is a preferred embodiment of the present invention, and its specific structure is as follows: Figure 1-2 As shown, it discloses the following improvements based on implementation method 1:

[0052] The circuit module 4 is configured to include:

[0053] The thyristor 8 is connected to the delay synchronizing machine 2. The function of the thyristor 8 in the circuit is to enable conduction and cutoff within microseconds and to act as a contactless switch to control the on and off of the circuit.

[0054] The thyristor 8 is a fast thyristor, which is usually of model KK200A. The advantage of this setting is that the thyristor 8 can be turned on quickly, thereby opening the water solenoid valve module 7.

[0055] A switch 9 is installed between the thyristor 8 and the water solenoid valve module 7. The function of the switch 9 is to switch the on / off state of the water solenoid valve 11 in the water solenoid valve module 7.

[0056] DC power supply 10 supplies power to thyristor 8, and DC power supply 10 supplies power to water solenoid valve 11 through switch 9;

[0057] A resistor 17 is connected in parallel with the water solenoid valve 11 in the water solenoid valve module 7.

[0058] In this design, the DC power supply 10, switch 9, thyristor 8, and resistor 17 are all integrated on the PVC board 22. In this design, the DC power supply 10, thyristor 8, switch 9, and high-power resistor 17 (the required resistance value of the high-power resistor can be determined according to the holding current of the thyristor 8 and the voltage of the DC power supply 10; in this design, it is set to a 30Ω high-power resistor) are individually fixed on the PVC board 22 to form circuit module 4, which makes the circuit arrangement orderly and facilitates fault diagnosis. At the same time, the selection of the PVC board 22 isolates each component from the metal below, thus providing insulation.

[0059] In practical applications, the positive terminal of DC power supply 10 is connected to the positive terminal of water solenoid valve 7, the negative terminal of water solenoid valve 7 is connected to the anode of thyristor 8, and the cathode of thyristor 8 is connected to the negative terminal of DC power supply 10. At the same time, a high-power resistor is connected in parallel across the two ends of air solenoid valve 7. The delay synchro 2 and thyristor 8 are connected by fiber optic II3 to BNC cable. Fiber optic II3 is connected to delay synchro 13, the inner core of BNC cable is connected to the gate of thyristor 8, and the outer conductor of BNC cable is connected to the negative terminal of DC power supply 10.

[0060] Working principle: DC power supply 10 supplies power to water solenoid valve module 7 through switch 9. In specific implementation, the signal of pressure sensor 1 is used as the time reference. The pulse signal generated by delay synchronizer 0 drives water solenoid valve module 7 to open the valve after a delay of about 30ms. The advantage of this setting is that no manual triggering is required. DC power supply 10 only needs to supply the corresponding DC power to thyristor 8. The signal generated by pressure sensor 1 at the front end of shock tube can immediately trigger water solenoid valve module 7 to work through thyristor 8 and switch 9 connected to delay synchronizer 2.

[0061] Example 3

[0062] This third embodiment is a preferred embodiment of the present invention, and its specific structure is as follows: Figure 2 , Figure 3 As shown, it discloses the following improvements based on implementation method 1:

[0063] The water-passing solenoid valve module 7 is configured to include:

[0064] The gas supply pipeline 13 connects the liquid storage tank 5 to the external driving gas source 12, and the ball valve I 14 is installed on the gas supply pipeline 13;

[0065] A water-passing solenoid valve 11 connects the liquid storage tank 5 to the pre-reserved small hole on the aircraft model 6 via a water supply pipeline 15.

[0066] Among them, a ball valve II 18 is also provided between the water solenoid valve 11 and the reserved small hole on the aircraft model 6. After the water solenoid valve 11 is opened, the water flow rate can be controlled by adjusting the ball valve II 18. The advantage of this setting is that the flow rate of the sprayed water can be controlled.

[0067] A pressure gauge is also installed on the connection branch 19 between the ball valve I14 and the liquid storage tank 5. In this case, a mechanical pressure gauge 20 is used.

[0068] A pressure reducing valve 21 is also provided between the driving air source 12 and the ball valve I 14. In this solution, the ball valve I 14, the ball valve II 18, the mechanical pressure gauge 20, the water solenoid valve 11 and the liquid storage tank 5 are connected to form the water solenoid valve module 7, which is connected to the aircraft model 6 to facilitate air injection, water injection operation and spray flow control.

[0069] The water-passing solenoid valve 11 is a bidirectional control valve that supports fluids (air, water, high-temperature water, oil, etc.), but the most commonly used fluids are air and water. The advantage of this design is that the normal operation of the water-passing solenoid valve 11 will not be affected by the fluid medium.

[0070] Working principle: During operation, first open ball valve I14, close water solenoid valve 11 and ball valve II18, and directly inject water into the front end of ball valve I14. When the water level in the storage tank 5 reaches the predetermined value, stop injecting water. Connect an air pipe to the front end of ball valve I14, and use a gas cylinder as an external driving air source 12. Through pressure reducing valve 21 and ball valve I14, the gas from the external driving air source 12 can be injected into the liquid level surface in the storage tank 5. During operation, the external driving air source 12 and the liquid storage tank 5 are in a vertical position. The air pressure can be adjusted by the pressure reducing valve 21 and the ball valve I 14 during the air injection process. The mechanical pressure gauge 20 can display the pressure value in real time. The advantage of this setting is that during the water injection process, the pressure applied to the liquid level surface can be precisely adjusted through various valves to control the liquid spraying flow rate. That is, in practical applications, the external driving air source 12 injects air into the liquid level surface of the liquid storage tank 5, so that the liquid in the liquid storage tank 2 is transported outward under pressure to ensure that its flow rate meets the spraying requirements. The air pressure is adjusted in real time by the pressure reducing valve 21 and the ball valve I 14 to meet the application requirements of different working conditions.

[0071] Example 4

[0072] This embodiment 4 is a preferred embodiment of the present invention, and its specific structure is as follows: Figure 3 As shown, the following improvements are disclosed based on embodiment 2:

[0073] The PVC board 22 is provided with multiple grooves 23 that are adapted to the external structure of the DC power supply 10, switch 9, and thyristor 8.

[0074] Each of the sinks 23 has a flexible layer 24 at its inner edge. The flexible layer 24 can be set with a stepped cross section and a hollow interior as needed, so that it has better deformation and support force to isolate the device from the side wall of the sink 23.

[0075] The PVC board 22 is provided with a pair of mounting holes 25 at the positions that mate with each sink 23.

[0076] In this design, a pre-reserved mounting groove 23 is provided on the PVC board 22 to initially define the positions of the DC power supply 10, switch 9, thyristor 8, and resistor 17. Then, by inserting cable ties (not shown) or mounting screws (not shown) into the mounting holes 25, the DC power supply 10, switch 9, thyristor 8, and resistor 17 are fixed to the PVC board 22 to ensure the stability of the structural components. Simultaneously, when using cable ties, a matching limiting groove (not shown) is also provided below the PVC board 22 to ensure that the bottom surface of the PVC board 22 remains flush after binding. Furthermore, a matching flexible pad can be provided at the point where the equipment meets the cable ties to reduce damage caused by pressure between the structural components and the cable ties when fixing the equipment. The flexible layer 24 serves as a flexible support, reducing damage caused by hard contact between the structural components and the groove 22 when fixing the equipment, and also ensuring the stability of the equipment installation by increasing friction.

[0077] The above solutions are merely illustrative examples of preferred embodiments, but are not limited thereto. When implementing this invention, appropriate substitutions and / or modifications can be made according to the user's needs.

[0078] The number of devices and processing scale described herein are for the purpose of simplifying the description of this utility model. Applications, modifications, and variations of this utility model will be readily apparent to those skilled in the art.

[0079] Although embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this utility model. Other modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and examples shown and described herein.

Claims

1. A system for mitigating plasma sheathing, comprising a pressure sensor disposed at the foremost tip of a shock tube, characterized in that, Also includes: A time-delay synchronizing machine connected to a pressure sensor via fiber optic cable I; Spraying device connected to a delay synchronizer via fiber optic II; The spraying device includes: The circuit module connected to the time delay synchronizer; A water-passing solenoid valve module electrically connected to the circuit module to switch the on / off state of the medium in the storage tank and the reserved small hole on the aircraft model.

2. The system for mitigating plasma sheathing as described in claim 1, characterized in that, The circuit module is configured to include: Thyristors connected to the time delay synchronizer; A switch is installed between the thyristor and the water-passing solenoid valve module; A DC power supply for powering thyristors; A resistor connected in parallel with the water solenoid valve in the water solenoid valve module; The DC power supply, switch, thyristor, and resistor are all integrated on the PVC board.

3. The system for mitigating plasma sheathing as described in claim 2, characterized in that, The water-passing solenoid valve module is configured to include: The gas supply pipeline connecting the liquid storage tank to the external driving gas source, and ball valve I installed on the gas supply pipeline; A water-passing solenoid valve that connects the liquid storage tank to a pre-drilled hole on the aircraft model via a water supply pipeline; Among them, a ball valve II is also provided between the water-passing solenoid valve and the reserved small hole on the aircraft model; A pressure gauge is also installed on the connection branch between ball valve I and the liquid storage tank.

4. The system for mitigating plasma sheaths as described in claim 3, characterized in that, A pressure reducing valve is also provided between the driving air source and ball valve I.

5. The system for mitigating plasma sheathing as described in claim 3, characterized in that, The water-passing solenoid valve is a two-way control valve.

6. The system for mitigating plasma sheathing as described in claim 2, characterized in that, The PVC board is provided with multiple grooves that are compatible with the external structure of DC power supplies, switches, and thyristors. Each settling tank has a flexible layer at its inner edge; The PVC panels are provided with a pair of mounting holes at positions that mate with each settling tank.

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