A plasma jet device based on ion wind driving

Abstract

The application discloses an ion wind driving based plasma jet device, which comprises a hollow cylinder body, a high-voltage metal needle electrode plate is installed in the cylinder body, a plurality of high-voltage metal needle electrodes are fixed on the high-voltage metal needle electrode plate in a ring array mode and are connected with a high-voltage excitation power circuit, a metal wall ground electrode is covered on the inner wall of the cylinder body, and an insulating medium ring is closely attached to the metal wall ground electrode and is arranged at intervals from the high-voltage metal needle electrode plate; the needle body of the high-voltage metal needle electrode, the insulating medium ring and the metal wall ground electrode form a plasma jet structure, the needle head of the high-voltage metal needle electrode and the metal wall ground electrode form an ion wind generation structure, the ion wind generation area and the plasma generation area are staggered and arranged, and the generation of the plasma jet is driven by the multi-stage ion wind. The application couples the ion wind structure and the plasma jet structure, does not need a large gas carrier device, expands the application scene of the device, and improves the performance of the plasma jet.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plasma, and relates to a plasma jet device based on ion wind driving. BACKGROUND

[0002] Atmospheric pressure plasma jet (APPJ) can generate high-activity non-equilibrium plasma in open space instead of narrow discharge gap, which separates the plasma from high-voltage electrode, greatly improves the use safety, and enriches the jet in a variety of active particles and charged particles; in addition, the gas temperature of the plasma can be close to room temperature under extreme non-equilibrium conditions, and these advantages make APPJ play an important role in material surface treatment, thin film deposition and biomedical applications.

[0003] However, the traditional APPJ device needs to introduce working gas through a gas cylinder, generate plasma in the device, and finally form a plasma jet under the action of gas flow. These technologies need very large gas transportation equipment, which limits their portability and practicality. At the same time, in the process of gas flow, the ionization of the gas is weakened, which reduces the ionization degree of the plasma and leads to the decline of the performance of the generated plasma jet. SUMMARY

[0004] In order to solve the above problems, the application provides a plasma jet device based on ion wind driving, which couples the ion wind structure and the plasma jet structure, does not need large gas carrier equipment, expands the application scenarios of the device, improves the performance of the plasma jet, and solves the problems in the prior art.

[0005] The technical scheme adopted by the application is a plasma jet device based on ion wind driving, which comprises a hollow cylinder, a high-voltage metal needle electrode plate is installed in the cylinder, a plurality of high-voltage metal needle electrodes are fixed on the high-voltage metal needle electrode plate in a ring array and connected with a high-voltage excitation power supply circuit, and the high-voltage metal needle electrode plate has mesh holes allowing gas to flow through;

[0006] The inner wall of the cylinder is covered with a metal wall ground electrode, and an insulating medium ring is tightly attached to the metal wall ground electrode and is arranged at intervals from the high-voltage metal needle electrode plate, and the high-voltage metal needle electrode is parallel to the metal wall ground electrode and the insulating medium ring;

[0007] The needle body of the high-voltage metal needle electrode, the insulating medium ring and the metal wall ground electrode constitute a plasma jet structure, the needle head of the high-voltage metal needle electrode and the metal wall ground electrode constitute an ion wind generation structure, the ion wind generation area and the plasma generation area are staggered, and the generation of the plasma jet is driven by multiple stages of ion wind.

[0008] Further, the high-voltage metal needle electrodes have the same length, and the needle heads of the high-voltage metal needle electrodes are aligned with the edges of the corresponding insulating medium rings; the high-voltage metal needle electrodes on a single high-voltage metal needle electrode plate and the corresponding insulating medium rings form an ion wind propulsion and plasma jet structure unit; and multiple jet structure units are combined to realize multi-stage ion wind driving.

[0009] Further, a metal rectangular mesh ground electrode is installed on the rear side of the insulating medium ring in the airflow direction, and the high-voltage metal needle electrode and the metal rectangular mesh ground electrode form a needle mesh structure for ion wind generation.

[0010] Further, the high-voltage metal needle electrodes of the same annular array have the same length, the lengths of the high-voltage metal needle electrodes on each annular array decrease from the center of the cross section of the cylinder outward, the needle heads of the high-voltage metal needle electrodes are aligned with the edges of the corresponding insulating medium rings, and multi-stage ion wind driving is realized.

[0011] Further, the length difference of the metal needles of adjacent rings is between 20 and 30 mm, the distance between adjacent insulating medium rings is half of the length difference of the high-voltage metal needle electrodes on the adjacent rings, the distance between adjacent rings is in the range of 1.5 mm to 6 mm, and the distance between the innermost high-voltage metal needle electrode and the inner wall of the cylinder is in the range of 3 mm to 20 mm.

[0012] Further, the high-voltage metal needle electrode plate is sequentially provided with a metal wire mesh high-voltage electrode and a metal rectangular mesh ground electrode in the airflow direction, the metal wire mesh high-voltage electrode and the metal rectangular mesh ground electrode are arranged in parallel with a distance of 8 to 10 mm, the metal wire mesh high-voltage electrode is fixed to the inner wall of the cylinder through a ring-shaped rigid insulating material mesh electrode support plate, and the metal wire mesh high-voltage electrode is connected to a high-voltage excitation power supply.

[0013] Further, the metal wire mesh high-voltage electrode and the metal rectangular mesh ground electrode are both circular in profile, the metal wire mesh high-voltage electrode has a linear metal mesh inside, and the metal rectangular mesh ground electrode has a rectangular metal mesh inside.

[0014] Further, the high-voltage metal needle electrode plate includes an insulating mesh plate, the insulating mesh plate has a plurality of annular conductive lines inside, the insulating mesh plate is provided with a plug hole for the high-voltage metal needle electrode to be inserted into and connected to the conductive lines, a plurality of high-voltage metal needle electrodes are fixed to the high-voltage metal needle electrode plate in an annular array and connected to a high-voltage excitation power supply through the conductive lines, the insulating mesh plate has a conductive line frame, and the remaining part is provided with air-permeable mesh holes;

[0015] Alternatively, the high-voltage metal needle electrode plate is a PCB circuit board, the circuit board is provided with a circuit matching the annular array of high-voltage metal needle electrodes, the circuit is connected to a high-voltage excitation power supply through a wire, and the high-voltage metal needle electrodes are supplied with power through the circuit plug hole on the circuit board.

[0016] Further, the gas inlet end of the cylinder is provided with a gas inlet partition plate, which is a porous structure for air passage.

[0017] Further, the outer wall of the cylinder is provided with an insulating shell, and an annular magnetic core is embedded in the insulating shell, for generating an axial magnetic field in the cylinder, so that the plasma moves spirally outward along the central axis in the cylinder, forming a rotating jet; the annular magnetic core is an axially magnetized neodymium iron boron magnet or an energized spiral coil.

[0018] The beneficial effects of the present application are:

[0019] The present application adopts the coupling of ion wind structure and plasma jet structure, and realizes the staggered arrangement of ion wind generation area and plasma generation area in layout. Compared with the traditional needle ring ion wind structure, the present application increases the number of high-voltage metal needle electrodes on each ring to improve the intensity of generated ion wind, and the high-voltage metal needle electrodes on each ring and the ground electrode on the cylinder wall constitute a first-stage ion wind driving, and the multi-ring annular array forms multi-stage ion wind driving, so that the generation of plasma jet can be finally driven without gas source excitation.

[0020] The acceleration of ion wind (internal airflow of the device) of the present application is realized by multi-stage coupling, which fully utilizes the advantages of internal ion wind of the device. On one hand, the generation of ion wind drives the flow of internal airflow of the device, drives the inflow of external gas, and promotes the injection of plasma jet; on the other hand, the generation of ion wind is the result of gas discharge, which produces a large number of active particles and charged particles, which finally merge into the plasma jet, so that the combination of the two flows strengthens the plasma jet, so that each stage of ion wind can enhance the generation of plasma in the plasma jet area, promote the generation of longer and brighter plasma jet, significantly improve the concentration of plasma in the jet, and greatly enhance the effect of plasma jet.

[0021] The addition of the magnetic field in the device of the present application promotes the ionization of gas, produces more active particles and charged particles, and on the other hand, the particles make spiral motion forward in the device due to the Lorentz force during the motion process, which enhances the entrainment and mixing of the jet, makes the particle mixing in the plasma jet more uniform, and makes the generated plasma jet more stable. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is a structural schematic diagram of an embodiment of the present application.

[0024] Figure 2 is a structural schematic diagram of a metal wire mesh high-voltage electrode in an embodiment of the present application.

[0025] Figure 3 is a structural schematic diagram of a metal rectangular mesh ground electrode in an embodiment of the present application.

[0026] Figure 4 is a structural schematic diagram of a high-voltage metal needle electrode plate in an embodiment of the present application.

[0027] Figure 5 is a structural schematic diagram of a multi-layer structure of a device cylinder wall in an embodiment of the present application.

[0028] Figure 6 is a structural schematic diagram of a structural unit of another embodiment of the present application.

[0029] Figure 7 is a structural schematic diagram of a structural unit in Figure 6 .

[0030] In the figure, 1 is a high-voltage excitation power supply, 2 is a mesh electrode support plate, 3 is a metal wire mesh high-voltage electrode, 4 is a metal rectangular mesh ground electrode, 5 is a high-voltage metal needle electrode plate, 6 is a high-voltage metal needle electrode, 7 is an insulating medium ring, 8 is a metal wall ground electrode, 9 is a ring-shaped magnetic core, 10 is an insulating shell, 11 is a jet outlet, 12 is an air inlet partition, 13 is an insulating mesh plate, 14 is a conductive circuit, 15 is a jack, and 16 is a ventilation mesh hole. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] Embodiment 1,

[0033] An ion wind-driven plasma jet device, as shown in Figure 1 , 4 , 6, includes a hollow cylinder, a high-voltage metal needle electrode plate 5 is installed in the cylinder, a plurality of high-voltage metal needle electrodes 6 are fixed in a ring array on the high-voltage metal needle electrode plate 5 and are electrically connected with a high-voltage excitation power supply 1, and the high-voltage metal needle electrode plate 5 has mesh holes allowing gas to flow through.

[0034] The inner wall of the cylinder is completely covered by the metal wall ground electrode 8, the insulating medium ring 7 is close to the metal wall ground electrode 8 and is arranged at intervals from the high-voltage metal needle electrode plate 5, and the high-voltage metal needle electrode 6 is parallel to the metal wall ground electrode 8 and the insulating medium ring 7.

[0035] The needle body of the high-voltage metal needle electrode 6, the insulating medium ring 7, and the metal wall ground electrode 8 form a plasma jet structure, the needle head of the high-voltage metal needle electrode 6 and the metal wall ground electrode 8 form an ion wind generation structure, the plasma jet structure and the ion wind generation structure are coupled to each other, the ion wind generation area and the plasma generation area are arranged alternately, and the generation of the plasma jet is driven by the multi-stage ion wind.

[0036] The metal electrodes in the cylinder form ion wind generation areas and plasma jet generation areas between each other or between the cylinder wall, the plasma jet structure is the main generation area of the plasma, the ion wind generation area penetrates the plasma jet generation area, and the generation of the plasma jet is driven by the multi-stage ion wind, which breaks through the limitation of gas cylinder and other gas transmission equipment, and the cooperation of the two areas compensates for the weakening of gas ionization in gas flow and enhances the generation of plasma in the device.

[0037] Embodiment 2,

[0038] One way to achieve multi-stage ion wind driving plasma jet:

[0039] As shown in Figure 1 , 4 The high-voltage metal needle electrode 6 is inserted into the insertion hole 15 on the high-voltage metal needle electrode plate 5 and is fixed, the lengths of the metal needles in the same annular array are consistent, the lengths of the metal needles on each annular array decrease from the center of the cross section of the cylinder outward, the length difference of the metal needles of adjacent rings is between 20-30mm, which can generate ion wind with faster flow rate, and the flow rate can reach 8m / s at the highest, and the generation efficiency of plasma is higher; the high-voltage metal needle electrode 6 can be powered through the conductive circuit 14 on the high-voltage metal needle electrode plate 5, the needle body part of the high-voltage metal needle electrode 6 participates in the generation of the plasma jet, and the needle head part generates ion wind through gas discharge.

[0040] The outermost ring of the high-voltage metal needle electrode plate 5 is not paved with the conductive circuit 14, and is used to be fixed on the outermost insulating medium ring 7. The insulating medium ring 7 is rigid, and can be made of materials with relatively large dielectric constant, such as quartz and ceramic. The insulating medium ring 7 is tightly attached to the metal wall ground electrode 8, and is arranged at intervals from the high-voltage metal needle electrode plate 5. The interval width between adjacent insulating medium rings 7 is half of the length difference of the metal needle electrodes on the adjacent rings, so that the insulating medium ring 7 and the exposed metal wall ground electrode 8 area between adjacent levels of high-voltage metal needle electrodes 6 each occupy half. The length of the insulating medium ring 7 is the space length of the plasma jet generation area (which affects the generation of plasma), and the length of the exposed metal wall ground electrode 8 area is the space length of the ion wind generation area (which affects the flow rate and thrust size of the ion wind). Here, the two space lengths are set to be equal, and the product structure can also adjust the length according to the specific size. The length of the exposed metal wall ground electrode 8 is between 10 mm and 15 mm, and the generated ion wind flow rate is large. The length of the insulating medium ring 7 determines the generation effect of the plasma jet, and here it is set to be equal to the length of the exposed metal wall electrode. The edge position of the insulating medium ring 7 is aligned with the position of the metal needle tip.

[0041] The high-voltage metal needle electrode plate 5, the annular array of high-voltage metal needle electrodes 6, the insulating medium ring 7, the high-voltage excitation power supply 1, and the metal wall ground electrode 8 together form a multi-stage ion wind-plasma jet coupling area of the device. The annular array of high-voltage metal needle electrodes 6, the insulating medium ring 7, and the metal wall ground electrode 8 form a plasma jet structure. Plasma jet will be generated between the high-voltage metal needle electrode 6 and the insulating medium ring 7. The plasma jet area is marked in Figure 1 The annular array of high-voltage metal needle electrodes 6 and the metal wall ground electrode 8 form a needle ring structure for generating ion wind. Gas discharge occurs in the direction of the needle tip, generating ion wind in the direction from the needle tip to the metal wall. The ion wind generation area is marked in Figure 1 In the multi-stage ion wind-plasma jet coupling area, multi-stage ion wind generation areas and plasma jet areas are formed, which are arranged alternately. The ion wind is pushed by multiple stages to eject the generated plasma jet from the jet outlet 11.

[0042] In some embodiments, the high-voltage metal needle electrode plate 5 includes an insulating mesh plate 13, the interior of the insulating mesh plate 13 is provided with a multi-layer annular conductive circuit 14, and a plurality of high-voltage metal needle electrodes 6 are fixed to the high-voltage metal needle electrode plate 5 in a ring array and connected to the high-voltage excitation power supply 1 through the conductive circuit 14; the influence of the metal rectangular mesh ground electrode 4 is effectively isolated to avoid the generation of reverse ion wind, and at the same time, power can be supplied to the high-voltage metal needle electrode 6; the insulating mesh plate 13 uses the conductive circuit 14 as a frame, and the rest of the part is provided with a breathable mesh 16, which effectively takes into account the circulation of gas. The mesh shape of the insulating mesh plate 13 is a multi-layer ring structure consistent with the conductive circuit 14. There is a socket 15 on the mesh plate for the high-voltage metal needle electrode 6 to be inserted into and connected to the conductive circuit 14. The diameter of the socket 15 is Ф=0.7mm. The conductive circuit 14 supplies power to the high-voltage metal needle electrodes 6 in the ring array through the socket 15. The high-voltage metal needle electrode plate 5 can also use a high-temperature and high-voltage resistant PCB circuit board. The circuit of the high-voltage metal needle electrode 6 that matches the circular array is drawn on the circuit board, connected to the high-voltage excitation power supply 1 through a wire, and power is supplied to the high-voltage metal needle electrode 6 through the circuit jack on the board.

[0043] In some embodiments, the metal wire mesh high voltage electrode 3, the metal rectangular mesh ground electrode 4, the mesh electrode support plate 2, the high voltage excitation power supply 1 and the metal wall ground electrode 8 together constitute the primary ion wind driving region of the device.

[0044] The metal wire mesh high-voltage electrode 3 and the metal rectangular mesh ground electrode 4 cooperate to form a wire mesh electrode structure of plasma wind, which is located at the beginning of the device and acts as a buffer to transport air to the rear area for ionization. Plasma jet can be achieved without this structure, but in the multi-stage plasma jet generation area at the rear, the space is closed and continuous, and the ionization effect will be weakened due to the limitation of air capacity. If there is a buffer, this problem can be overcome.

[0045] The high-voltage excitation power supply 1 is connected to the metal wire mesh high-voltage electrode 3 and the high-voltage metal needle electrode plate 5 inside the device through a wire. Any DC power supply, AC power supply or pulse power supply can be used to supply power to the high-voltage electrodes in the device.

[0046] The mesh electrode support plate 2 is an annular rigid insulating material, which can be made of high-temperature resistant rigid materials such as glass and ceramics. It is close to the metal wall ground electrode 8 on the wall of the device cylinder and is used to fix the metal wire mesh high-voltage electrode 3 and prevent the metal wire mesh high-voltage electrode 3 from contacting and conducting with the metal wall ground electrode 8.

[0047] The metal wall ground electrode 8 covers the entire inner wall of the cylinder, and it constitutes the electrode structure for ion wind generation and plasma jet generation inside the device. At the same time, the metal rectangular mesh ground electrode 4 is grounded through electrical connection. In the primary ion wind pushing area, it serves as the annular part in the mesh ring structure for ion wind generation, and in the multi-stage ion wind-plasma jet coupling area, it serves as the ground electrode part of the dielectric barrier discharge generated by plasma and the annular part in the needle ring structure for ion wind generation.

[0048] like Figure 2 As shown, the metal wire mesh high-voltage electrode 3 has a circular outline and a linear metal mesh inside. The metal wire mesh high-voltage electrode 3 is embedded in the mesh electrode support plate 2 and is connected to the positive polarity high-voltage excitation power supply 1 through a wire.

[0049] like Figure 3 As shown, the metal rectangular mesh ground electrode 4 is similar in structure to the metal wire mesh high-voltage electrode 3, but the mesh shape is rectangular. The metal rectangular mesh ground electrode 4 is directly connected to the metal wall ground electrode 8 of the cylinder wall and fixed by welding or bonding.

[0050] A metal wire mesh high-voltage electrode 3 and a metal rectangular mesh ground electrode 4 are arranged in parallel, forming a wire mesh electrode structure for generating ion wind. The spacing between the two metal meshes is between 8 and 10 mm, ensuring uniform gas discharge between the electrodes. The generated ion wind velocity can reach a maximum of 1.8 m / s. If the electrode spacing exceeds this range, the resulting ion wind velocity decreases. If the electrode spacing is smaller than this range, the ionized gas between the electrodes is limited. If the electrode spacing is larger than this range, the discharge conditions between the electrodes increase, reducing gas ionization. If the two electrode plates are tilted (not parallel), the voltage between the electrodes will be unstable and the discharge voltage will be distorted, which is not conducive to the generation of ion wind. This area is the primary ion wind propulsion region, where the generated ion wind drives the inflow of external air and propels the initially ionized gas backward into the multi-stage ion wind-plasma jet coupling region. Testing has shown that the electrode structure composed of a wire mesh high-voltage electrode and a grid-shaped ground electrode achieves better gas ionization and generates a faster ion wind velocity.

[0051] In some embodiments, the air inlet partition 12 is a ventilated porous structure and does not participate in the generation of ion wind and plasma in the device. It is only provided to prevent the outermost metal wire mesh high-voltage electrode 3 from being exposed to the outside, which may cause a risk of contact during use.

[0052] In some embodiments, the high-voltage excitation power supply 1 uses a 10KV direct current to supply power to the high-voltage electrodes in the device. Optionally, an alternating current power supply or a pulse power supply can also be used for power supply.

[0053] The metal wire mesh high-voltage electrode 3 is at a high temperature in a high-voltage state (high-temperature resistance is required), and a metal material with low work function is more conducive to the generation of plasma. In this embodiment, the metal wire mesh high-voltage electrode 3 is made of tungsten, which meets the theoretical requirements of high-temperature resistance. In theory, metal materials such as tungsten-copper alloy and nickel can also be used as electrode materials. However, considering that a metal material with low work function is more conducive to the generation of plasma, the tungsten electrode is a better choice. The diameter of the circular profile of the metal wire mesh high-voltage electrode 3 is D1=28 mm, the diameter of the metal wire is 0.05 mm, and the gap between adjacent metal wires is L1=3 mm.

[0054] The metal rectangular mesh ground electrode 4 is made of aluminum, and can also be made of conductive metals such as copper and copper alloy to provide a stable ground electrode voltage. The diameter of the circular profile of the metal rectangular mesh ground electrode 4 is D2=30 mm, the diameter of the metal wire is 0.05 mm, the side length of the rectangular mesh hole is L2=3 mm, and L3=3 mm. The metal wire mesh high-voltage electrode 3 and the metal rectangular mesh ground electrode 4 form a wire mesh structure, which generates ion wind from the metal wire mesh high-voltage electrode 3 to the metal wall ground electrode 8 to push the airflow and the generated plasma to flow forward when the high-voltage excitation power supply 1 is powered.

[0055] In some embodiments, the high-voltage metal needle electrode plate 5 adopts a five-layer annular array. The diameter of the high-voltage metal needle electrode plate 5 is D3=30 mm. In the device design, the number of layers can be adjusted according to the actual situation. The spacing between adjacent annular arrays can be reduced to increase the number of layers of the annular array, but the diameter of the high-voltage metal needle electrode plate 5 must be within 40 mm to ensure that the inner layer of the annular metal needle participates in the generation of plasma and ion wind within a certain range (the innermost layer fails first and then spreads to the outer layer), avoiding the failure of the innermost metal needle. When the diameter is too large, the electrode distance exceeds the discharge condition of the electrode structure for ion wind generation and plasma generation, and gas discharge does not occur. The innermost layer fails first because of the largest spacing. The more layers of the annular array, the stronger the ion wind generated, and the more charged particles and active particles in the generated plasma jet. However, the power consumption of the corresponding device is higher, and the material requirements for the device are also higher.

[0056] In this embodiment, the length difference of the metal needles of adjacent rings is set to 20 mm, and the spacing between adjacent rings is l=3 mm. In this embodiment, a tungsten needle with a diameter of Φ=0.7 mm and a needle tip radius of 70 μm is used as a metal needle electrode. Metal needles with a diameter of 0.7 mm or less can also be used. Of course, the smaller the diameter of the metal needle, the better the discharge effect (mainly affecting the discharge effect of the plasma generation electrode structure).

[0057] The spacing between adjacent rings ranges from 1.5mm to 6mm. This spacing determines the density of the high-voltage metal needle electrodes 6 within the device. When the spacing is too small, the high-voltage metal needle electrodes are densely packed, increasing the average electric field energy within the device and weakening the gas discharge within the space. When the spacing is too large, the number of layers decreases, reducing the number of stages of multi-stage ion wind-driven plasma jets and the performance of the generated plasma jets. In Example 2, the spacing between adjacent rings is set to 3mm, which achieves a five-stage ion wind-driven plasma jet and maximizes the average discharge power of the high-voltage metal needle electrodes (the overall discharge power of the device is averaged over the metal electrode needles).

[0058] In the electrode structure for ion wind generation and plasma production, the distance between the innermost high-voltage metal needle electrode 6 and the inner wall of the cylinder is 3mm~20mm. If it exceeds 20mm, the plasma electrode structure composed of the innermost high-voltage metal needle electrode 6 and the metal wall will no longer discharge to generate plasma.

[0059] In some embodiments, the insulating dielectric ring 7 is made of alumina ceramic material and is close to the metal wall ground electrode 8. The spacing and width of adjacent insulating dielectric rings 7 are set to 10 mm, and the edge position of each insulating dielectric ring 7 is aligned with the needle position of each annular array metal needle.

[0060] like Figure 5 As shown, the insulating dielectric ring 7, the metal wall ground electrode 8, the annular magnetic core 9 and the insulating shell 10 constitute the cylindrical wall of the device; the innermost layer is the insulating dielectric ring 7, and the inner diameter of the cylindrical wall of the device (excluding the insulating dielectric ring 7) is 30 mm.

[0061] The insulating shell 10 serves as the outer shell of the device and can be made of insulating materials such as plastic and rubber. It is used to isolate the internal and external environments, provide a strict airtight environment for the device, and can be touched and used by operators.

[0062] The annular magnetic core 9 is embedded in the insulating shell 10, and an axial magnetic field direction can be generated inside the device. Driven by the ion wind inside the device, the plasma movement direction radiates from the center to the cylinder wall. In the internal magnetic field, it is affected by the Lorentz force and moves outward along the central axis in a spiral, forming a rotating jet inside, so that the plasma generated inside the device is fully mixed and evenly, and a more stable plasma jet is obtained.

[0063] The annular magnetic core 9 is made of axial magnetization neodymium iron boron magnet; the annular magnetic core 9 can also use a spiral coil energized, the magnetic field size in the device is controlled by controlling the current, further to achieve the effect of controlling the plasma characteristics. But pay attention to the thermal effect of the spiral coil when energized, consider the selection of insulating medium material or reconsider the installation position; the insulating material can be selected from high-temperature silicone rubber, which can withstand the heat of the coil and maintain the original shape without deformation; the installation position: the annular magnetic core 9 is not embedded in the insulating shell 10, and the long annular axial magnetization neodymium iron boron magnet is directly wrapped outside the insulating shell 10.

[0064] The metal wall ground electrode 8 is tightly attached to the inside of the insulating shell 10 of the device barrel, which is grounded through a wire and constitutes the ground electrode of the plasma generating dielectric barrier discharge structure and the ion wind generating needle ring structure. The material of the metal ground electrode can be selected from conductive metals such as copper and aluminum.

[0065] Example 3,

[0066] Another way to achieve multi-stage ion wind driven plasma jet:

[0067] As Figure 6 shown, the high-voltage metal needle electrode plate 5 has only two ring structures, and the distance between adjacent rings is 3mm; the central high-voltage metal needle electrode 6 is located at the center axis of the device, and the outer high-voltage metal needle electrode 6 is inserted on the high-voltage metal needle electrode plate 5 around the central metal annular array, under the excitation of the high-voltage excitation power supply 1, the annular array of high-voltage metal needle electrode 6, insulating medium ring 7 and metal wall ground electrode 8 constitute a dielectric barrier discharge structure, which generates a plasma jet (marked in Figure 6 ).

[0068] The mutual influence between the electrodes in the device of example 2 results in that part of the space in the device is not fully utilized (see the blank part in Figure 1 ), and the generation efficiency of ion wind and plasma is reduced. Compared with example 2, the high-voltage metal needle electrode 6 of this embodiment participates in the generation of plasma, and the influence between the electrodes is reduced, and the plasma generation efficiency in the internal structure of the device is higher.

[0069] The high-voltage metal needle electrode 6 on the single high-voltage metal needle electrode plate 5 and the corresponding position of the insulating medium ring 7 constitute an ion wind propulsion and plasma jet structure unit.

[0070] As Figure 7As shown, multiple ion wind propulsion and plasma jet structure units are coupled, and adjacent structure units are combined together through inlay insertion, bonding, external fixation and other methods at the coupling position. Each structure unit is a first-level ion wind propulsion and plasma jet generator, and the complete plasma jet coupling device is formed through multi-level coupling. Further, other structure units with characteristics can be added on the basis of the coupling structure to optimize the plasma jet device. For example, a conical outlet structure unit can be designed at the final jet outlet, so that the plasma jet is more concentrated in a smaller area when flowing out. Such a structure can cope with application scenarios that require high-speed plasma jet and small plasma processing.

[0071] The flexibility is high, and the coupling of the plasma jet device can be flexibly combined and set according to the application scenario and technical index. As long as the coupling structures between them do not conflict, structure units with characteristics can be designed to meet the needs of different application scenarios.

[0072] In some embodiments, a metal rectangular mesh ground electrode 4 is installed on the back side of the insulating medium ring 7 along the airflow direction. The high-voltage metal needle electrode 6 not only forms a needle ring structure for ion wind generation with the cylinder wall metal wall ground electrode 8, but also forms a needle mesh structure for ion wind generation with the metal rectangular mesh ground electrode 4, which assists in enhancing the ion wind and generating stronger ion wind thrust (the ion wind is marked in the figure). This can effectively improve the gas flow rate inside the device.

[0073] Embodiment 4,

[0074] The structure of embodiment 2 is used as a first-level ion wind propulsion and plasma jet generation unit, and the structure unit of embodiment 3 is coupled behind the jet outlet 11, and the inner diameter size needs to be consistent. The addition of a first-level ion wind propulsion and plasma jet area can enhance the plasma jet effect of the device of embodiment 2.

[0075] Experimental data:

[0076] In the test, in order to obtain obvious plasma jet effect, at the same time, compared with the plasma jet generating device with a jet outlet diameter of 1 mm and the gas source participating, the jet outlet of the device of embodiment 2 is additionally provided with a conical pipe with a pipe hole diameter of 1 mm and a length of 20 mm, under the excitation of the same 10 kv alternating voltage, the plasma jets generated by the two devices are compared by camera shooting, the plasma jet device with the gas source participating is inhaled with air at a gas flow rate of 6 L / min, the maximum point of the gas flow rate is 18.8 m / s at the air outlet, and the generated plasma jet can reach 9 mm; while the jet length generated by the device of embodiment 2 can reach 10 mm, but the plasma composition in the plasma jet is significantly improved, the jet becomes more concentrated, and the brightness is also improved to a certain extent; therefore, the plasma jet effect generated by the plasma jet generating device without the participation of the gas source device of embodiment 2 can reach the plasma jet effect generated by the plasma jet generating device inhaled with air at a gas flow rate of 6 L / min.

[0077] In the case of coupling of three-level structural units in embodiment 3, the ion wind speed generated by a single structural unit in the device can reach 10 m / s, while the maximum ion wind speed generated by the traditional needle ring structure can reach 8 m / s, and the gas flow rate in the whole coupling structure can reach 25 m / s, compared with the plasma jet generating device with a jet outlet diameter of 1 mm and the gas source participating, when inhaled with air at a gas flow rate of 10 L / min, the maximum point of the gas flow rate is 25.6 m / s at the air outlet, and the generated plasma jet can reach 13 mm, the jet length generated by the device of embodiment 3 can reach 15 mm, and the plasma ion composition in the plasma jet is significantly improved, and the jet becomes more concentrated. Therefore, the plasma jet effect generated by the plasma jet generating device of embodiment 3 can reach the plasma jet effect generated by the plasma jet generating device inhaled with air at a gas flow rate of 10 L / min.

[0078] The embodiment of the present application provides a structure for a plasma jet generating device which does not depend on an external gas carrier device to supply gas flow. The problem of needing a gas source in conventional plasma generation is solved by the way of multi-stage ion wind driving plasma jet, and a structure for multi-stage ion wind driving plasma jet generation is proposed, the ion wind generation area and the plasma jet generation area are reasonably planned in the device, the two areas are staggered, each performs its own function, and cooperates with each other, and finally the required function is realized.

[0079] The above only describes the preferred embodiments of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application is included in the protection scope of the present application.

Claims

1. A plasma jet device driven by ion wind, comprising a hollow cylinder, characterized in that: A high-voltage metal needle electrode plate (5) is installed in the cylinder, a plurality of high-voltage metal needle electrodes (6) are fixed to the high-voltage metal needle electrode plate (5) in a ring array and are connected to a high-voltage excitation power supply (1) circuit, and the high-voltage metal needle electrode plate (5) has mesh holes that allow gas to flow; The inner wall of the cylinder is covered with a metal wall ground electrode (8), the insulating dielectric ring (7) is closely attached to the metal wall ground electrode (8) and is arranged at intervals starting from the high-voltage metal needle electrode plate (5), the high-voltage metal needle electrode (6) is parallel to the metal wall ground electrode (8) and the insulating dielectric ring (7); the needle tip of the high-voltage metal needle electrode (6) is aligned with the edge of the insulating dielectric ring (7) at the corresponding position; The needle body of the high-voltage metal needle electrode (6), the insulating medium ring (7), and the metal wall ground electrode (8) constitute a plasma jet structure, and the needle head of the high-voltage metal needle electrode (6) and the metal wall ground electrode (8) constitute an ion wind generation structure. The ion wind generation area and the plasma generation area are arranged in an alternating manner, and the generation of the plasma jet is driven by the multi-stage ion wind.

2. The plasma jet device based on ion wind drive according to claim 1, characterized in that: The high-voltage metal needle electrodes (6) are of uniform length, and the high-voltage metal needle electrodes (6) on a single high-voltage metal needle electrode plate (5) and the insulating medium ring (7) at the corresponding position constitute an ion wind propulsion and plasma jet structural unit; a plurality of jet structural units are combined to realize multi-stage ion wind drive.

3. The plasma jet device based on ion wind drive according to claim 2, characterized in that: Along the airflow direction, a metal rectangular mesh ground electrode (4) is installed on the rear side of the insulating medium ring (7), and the high-voltage metal needle electrode (6) and the metal rectangular mesh ground electrode (4) form a needle mesh structure for generating ion wind.

4. The plasma jet device based on ion wind drive according to claim 1, characterized in that: The high-voltage metal needle electrodes (6) in the same annular array have the same length, and the length of the high-voltage metal needle electrodes (6) on each annular ring decreases from the center of the cross section of the cylinder toward the outside, thereby realizing multi-stage ion wind drive.

5. The plasma jet device based on ion wind drive according to claim 4, characterized in that: The length difference between the high-voltage metal needle electrodes (6) of adjacent rings is between 20 and 30 mm, and the spacing width between adjacent insulating medium rings (7) is half of the length difference between the high-voltage metal needle electrodes (6) on adjacent rings; the spacing between adjacent rings ranges from 1.5 mm to 6 mm, and the distance between the innermost high-voltage metal needle electrode (6) and the inner wall of the cylinder is from 3 mm to 20 mm.

6. The plasma jet device driven by ion wind according to claim 4, characterized in that: A metal wire mesh high-voltage electrode (3) and a metal rectangular mesh ground electrode (4) are sequentially installed on the air inlet side of the high-voltage metal needle electrode plate (5) along the airflow direction. The metal wire mesh high-voltage electrode (3) and the metal rectangular mesh ground electrode (4) are arranged in parallel with a spacing of 8 to 10 mm. The metal wire mesh high-voltage electrode (3) is fixed to the inner wall of the cylinder through a mesh electrode support plate (2) made of an annular rigid insulating material. The metal wire mesh high-voltage electrode (3) is connected to a high-voltage excitation power supply (1).

7. The plasma jet device based on ion wind drive according to claim 6, characterized in that: The metal wire mesh high-voltage electrode (3) and the metal rectangular mesh ground electrode (4) both have circular contours; the internal shape of the metal wire mesh high-voltage electrode (3) is a linear metal mesh, and the internal shape of the metal rectangular mesh ground electrode (4) is a rectangular metal mesh.

8. The plasma jet device driven by ion wind according to claim 1, characterized in that: The high-voltage metal needle electrode plate (5) includes an insulating mesh plate (13), the interior of the insulating mesh plate (13) is provided with a multi-layer annular conductive circuit (14), the insulating mesh plate (13) is provided with a socket (15) for the high-voltage metal needle electrode (6) to be inserted and connected to the conductive circuit (14), a plurality of high-voltage metal needle electrodes (6) are fixed to the high-voltage metal needle electrode plate (5) in an annular array and are connected to the high-voltage excitation power supply (1) through the conductive circuit (14), the insulating mesh plate (13) uses the conductive circuit (14) as a frame, and the remaining part is provided with a breathable mesh (16); Alternatively, the high-voltage metal needle electrode plate (5) is a PCB circuit board, on which a circuit for the high-voltage metal needle electrodes (6) matching the annular array is drawn, which is connected to the high-voltage excitation power supply (1) via a wire, and power is supplied to the high-voltage metal needle electrodes (6) via a circuit jack on the circuit board.

9. The plasma jet device based on ion wind drive according to claim 6, characterized in that: An air inlet baffle (12) is provided at the air inlet end of the cylinder, and the air inlet baffle (12) is a ventilated pore structure.

10. The plasma jet device based on ion wind drive according to claim 1, characterized in that: The outer wall of the cylinder is provided with an insulating shell (10), and an annular magnetic core (9) is embedded in the insulating shell (10) for generating an axial magnetic field inside the cylinder, so that the plasma moves outward along the central axial spiral in the cylinder to form a rotating jet; the annular magnetic core (9) is an axially magnetized neodymium iron boron magnet or a energized spiral coil.

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