Plasma jet device based on ionic wind driving

Abstract

The invention discloses a plasma jet device based on ionic wind driving, which comprises a hollow cylinder, a high-voltage metal needle electrode plate is mounted in the cylinder, a plurality of high-voltage metal needle electrodes are fixed on the high-voltage metal needle electrode plate in an annular array manner and are connected with a high-voltage excitation power supply circuit, and the inner wall of the cylinder is covered with a metal wall ground electrode. The insulating medium rings cling to the metal wall ground electrode and are 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 ionic wind generation structure, ionic wind generation areas and plasma generation areas are arranged in a staggered manner, and generation of plasma jet is driven by multistage ionic wind. The ion wind structure and the plasma jet structure are coupled, large gas carrier equipment is not needed, the application scene of the device is expanded, and meanwhile the plasma jet performance is improved.

Description

Technical Field

[0001] The invention belongs to the field of plasma technology and relates to a plasma jet device driven by ion wind. Background Art

[0002] Atmospheric pressure plasma jet (APPJ) can produce highly active non-equilibrium plasma in open space rather than in a narrow discharge gap, which separates the plasma from the high-voltage electrode, greatly improving the safety of use. At the same time, the jet is rich 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. These advantages make APPJ play an important role in material surface treatment, thin film deposition and biomedical applications.

[0003] However, traditional APPJ devices require the introduction of working gas through gas cylinders to generate plasma inside the device, and ultimately form a plasma jet under the action of the airflow. These technologies require very large gas transportation equipment, limiting their portability and practicality. At the same time, during the gas flow process, the ionization of the gas is weakened, which reduces the degree of plasma ionization and leads to a decrease in the performance of the generated plasma jet. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a plasma jet device driven by ion wind. By coupling the ion wind structure and the plasma jet structure, no large-scale gas carrier equipment is required, the application scenarios of the device are expanded, and the performance of the plasma jet is improved, thereby solving the problems existing in the prior art.

[0005] The technical solution adopted by the present invention is a plasma jet device driven by ion wind, comprising 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 to the high-voltage metal needle electrode plate in a circular array and connected to a high-voltage excitation power supply circuit, and the high-voltage metal needle electrode plate has mesh holes that allow gas to flow; The inner wall of the cylinder is covered with a metal wall ground electrode, and the insulating medium ring is closely attached to the metal wall ground electrode and is arranged at intervals starting 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; 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 arranged alternately, and the generation of plasma jets is driven by multi-stage ion winds.

[0006] Furthermore, the high-voltage metal needle electrodes are of consistent length, and the needle tips of the high-voltage metal needle electrodes are aligned with the edges of the insulating medium rings at corresponding positions; the high-voltage metal needle electrodes on a single high-voltage metal needle electrode plate and the insulating medium rings at corresponding positions constitute ion wind propulsion and plasma jet structural units; and multiple jet structural units are combined to realize multi-stage ion wind drive.

[0007] Furthermore, along the airflow direction, a metal rectangular mesh ground electrode is installed on the rear side of the insulating medium ring, and the high-voltage metal needle electrode and the metal rectangular mesh ground electrode constitute a needle mesh structure for generating ion wind.

[0008] Furthermore, the high-voltage metal needle electrodes in the same annular array have the same length, and the length of the high-voltage metal needle electrodes on each ring decreases from the center of the cross-section of the cylinder to the outside. The needle heads of the high-voltage metal needle electrodes are aligned with the edges of the insulating medium rings at corresponding positions to achieve multi-stage ion wind drive.

[0009] Furthermore, the difference in length of the metal needles of adjacent rings is between 20 and 30 mm, and the spacing width between adjacent insulating medium rings is half of the difference in length of the high-voltage metal needle electrodes on adjacent rings; the range of the spacing between adjacent rings is 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 3 mm to 20 mm.

[0010] Furthermore, a metal wire mesh high-voltage electrode and a metal rectangular mesh ground electrode are sequentially installed on the air inlet side of the high-voltage metal needle electrode plate along the airflow direction. The metal wire mesh high-voltage electrode and the metal rectangular mesh ground electrode are arranged in parallel with a spacing of 8 to 10 mm; the metal wire mesh high-voltage electrode is fixed to the inner wall of the cylinder through a mesh electrode support plate of an annular rigid insulating material, and the metal wire mesh high-voltage electrode is connected to a high-voltage excitation power supply.

[0011] Furthermore, the metal wire mesh high voltage electrode and the metal rectangular mesh ground electrode both have circular contours, the internal shape of the metal wire mesh high voltage electrode is a linear metal mesh, and the internal shape of the metal rectangular mesh ground electrode is a rectangular metal mesh.

[0012] Furthermore, the high-voltage metal needle electrode plate includes an insulating mesh plate, the interior of the insulating mesh plate is provided with a multi-layer annular conductive circuit, the insulating mesh plate is provided with a jack for the high-voltage metal needle electrode to be inserted and connected to the conductive circuit, 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 circuit, the insulating mesh plate uses the conductive circuit as a frame, and the rest of the insulating mesh plate is provided with air-permeable mesh holes; Alternatively, the high-voltage metal needle electrode plate is a PCB circuit board, on which is drawn a circuit for high-voltage metal needle electrodes matching the annular array, which is connected to a high-voltage excitation power supply via a wire, and power is supplied to the high-voltage metal needle electrodes via a circuit jack on the circuit board.

[0013] Furthermore, an air inlet baffle is provided at the air inlet end of the cylinder, and the air inlet baffle is a ventilated pore structure.

[0014] Furthermore, an insulating shell is provided on the outer wall of the cylinder, in which an annular magnetic core is embedded, which is used to generate an axial magnetic field inside the cylinder, and the plasma moves outward along the central axial spiral in the cylinder to form a rotating jet; the annular magnetic core is an axially magnetized neodymium iron boron magnet or an energized spiral coil.

[0015] The beneficial effects of the present invention are: The present invention couples the ion wind structure and the plasma jet structure, and realizes the staggered arrangement of the ion wind generation area and the plasma generation area in the layout. Compared with the traditional needle-ring ion wind structure, the present invention increases the number of high-voltage metal needle electrodes on each ring to improve the intensity of the generated ion wind. At the same time, the high-voltage metal needle electrodes on each ring and the ground electrode on the cylinder wall constitute a primary ion wind drive. The multi-ring annular array forms a multi-stage ion wind drive, which can ultimately drive the generation of plasma jets without gas source excitation.

[0016] The acceleration of the ion wind (airflow inside the device) of the present invention is achieved through multi-stage coupling, giving full play to the advantages of the ion wind inside the device. On the one hand, the generation of ion wind promotes the flow of airflow inside the device through multi-stage, drives the inflow of external gas, and promotes the ejection of plasma jet; on the other hand, the generation of ion wind is the result of gas discharge, which will produce a large number of active particles and charged particles, and finally merge into the plasma jet. The combination of the two streams strengthens the plasma jet, so that each level of ion wind can enhance the generation of plasma in the plasma jet area, promote the generated plasma jet to be longer and brighter, significantly increase the concentration of plasma in the jet, and greatly enhance the effect of the plasma jet.

[0017] The addition of the magnetic field inside the device of the present invention, on the one hand, promotes the ionization of the gas and produces more active particles and charged particles. On the other hand, the particles are pushed forward by the spiral motion inside the device due to the Lorentz force during the movement, which enhances the entrainment and mixing of the jet, making the particles in the plasma jet more evenly mixed and the generated plasma jet performance more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1It is a schematic structural diagram of an embodiment of the present invention.

[0020] Figure 2 Schematic diagram of the structure of the metal wire mesh high voltage electrode in an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the structure of the metal rectangular mesh ground electrode in an embodiment of the present invention.

[0022] Figure 4 Schematic diagram of the structure of the high-voltage metal needle electrode plate in an embodiment of the present invention.

[0023] Figure 5 It is a schematic diagram of the multi-layer structure of the cylinder wall of the device according to an embodiment of the present invention.

[0024] Figure 6 It is a schematic diagram of a structural unit of another embodiment of the present invention.

[0025] Figure 7 yes Figure 6 Schematic diagram of the structural unit coupling in .

[0026] Among them, 1. high-voltage excitation power supply, 2. mesh electrode support plate, 3. metal wire mesh high-voltage electrode, 4. metal rectangular mesh ground electrode, 5. high-voltage metal needle electrode plate, 6. high-voltage metal needle electrode, 7. insulating medium ring, 8. metal wall ground electrode, 9. annular magnetic core, 10. insulating shell, 11. jet outlet, 12. air inlet partition, 13. insulating mesh plate, 14. conductive line, 15. jack, 16. ventilation mesh. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Embodiment 1, A plasma jet device based on ion wind drive, such as Figure 1 , 4 , 6, comprising 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 to the high-voltage metal needle electrode plate 5 in a circular 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 completely covered by the metal wall ground electrode 8, the insulating medium ring 7 is closely attached to the metal wall ground electrode 8 and arranged at intervals starting 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; 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 generating structure. The plasma jet structure and the ion wind generating structure are coupled with each other, and the ion wind generating area and the plasma generating area are arranged alternately, and the generation of plasma jet is driven by multi-stage ion wind.

[0029] The metal electrodes in the cylinder form an ion wind generating area and a plasma jet generating area between each other or with the cylinder wall. The plasma jet structure is the main generating area of ​​plasma. The ion wind generating area is interspersed with the plasma jet generating area. The generation of plasma jet is driven by multi-stage propulsion of ion wind, breaking through the limitations of gas transmission equipment such as gas cylinders. At the same time, the cooperation of the two areas compensates for the weakening of gas ionization in gas flow and enhances the generation of plasma inside the device.

[0030] Embodiment 2, One way to achieve multi-stage ion wind driven plasma jet: like Figure 1 , 4 As shown, the high-voltage metal needle electrode 6 is inserted into the socket 15 on the high-voltage metal needle electrode plate 5 and fixed. The lengths of the metal needles in the same annular array are consistent, and the lengths of the metal needles on each ring decrease from the center of the cross-section of the cylinder to the outside. The length difference of the metal needles in adjacent rings is between 20 and 30 mm, which can generate an ion wind with a faster flow rate, the maximum flow rate can reach 8 m / s, and the plasma generation efficiency is higher; the high-voltage metal needle electrode 6 can be powered by the conductive line 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 gas discharge to generate ion wind.

[0031] The outermost ring of the high-voltage metal needle electrode plate 5 is not provided with a conductive line 14 and is used to be fitted and fixed on the outermost insulating medium ring 7 . The insulating dielectric ring 7 is rigid and can be made of a material with a relatively large dielectric constant, such as quartz, ceramic, etc. The insulating dielectric ring 7 is close to the metal wall ground electrode 8 and is arranged at intervals starting from the high-voltage metal needle electrode plate 5. The spacing width of adjacent insulating dielectric rings 7 is half of the difference in length of the metal needle electrodes on the adjacent rings, ensuring that the insulating dielectric ring 7 and the exposed metal wall ground electrode 8 area each occupy half between the adjacent high-voltage metal needle electrodes 6. The length of the insulating dielectric ring 7 is the spatial length of the plasma jet generation area (affecting the generation of plasma), and the length of the exposed metal wall ground electrode 8 area is the spatial length of the ion wind generation area (affecting the flow rate of the ion wind and the magnitude of the thrust). Here, the two spatial lengths are set to be equal. The product structure can also adjust the set length according to the specific size. The length of the exposed metal wall ground electrode 8 is between 10mm and 15mm, and the generated ion wind flow rate is relatively large. The length of the insulating dielectric ring 7 determines the generation effect of the plasma jet. Here, the length is set to be equal to the length of the exposed metal wall electrode. The edge position of the insulating dielectric ring 7 is aligned with the position of the metal needle needle.

[0032] The high-voltage metal needle electrode plate 5, the high-voltage metal needle electrode 6 in an annular array, the insulating medium ring 7, the high-voltage excitation power supply 1 and the metal wall ground electrode 8 together constitute the multi-stage ion wind-plasma jet coupling area of ​​the device. The high-voltage metal needle electrode 6 in an annular array, the insulating medium ring 7 and the metal wall ground electrode 8 constitute a plasma jet structure. A plasma jet will be generated between the high-voltage metal needle electrode 6 and the insulating medium ring 7. The plasma jet area is Figure 1 As indicated in the figure, the high-voltage metal needle electrode 6 and the metal wall ground electrode 8 of the annular array constitute a needle ring structure for generating ion wind. Gas discharge occurs in the direction of the metal needle tip, generating ion wind in the direction from the needle tip to the metal wall. The ion wind generation area is Figure 1 In the multi-stage ion wind-plasma jet coupling zone, a multi-stage ion wind generation zone and a plasma jet zone are formed, which are arranged alternately, and the ion wind is driven by multiple stages to eject the generated plasma jet from the jet outlet 11.

[0033] In some embodiments, the high-voltage metal needle electrode plate 5 includes an insulating mesh plate 13, and a multi-layer annular conductive circuit 14 is provided inside the insulating mesh plate 13. 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 connected to a 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 power can be supplied to the high-voltage metal needle electrode 6 at the same time; 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, and the conductive circuit 14 supplies power to the high-voltage metal needle electrodes 6 in the annular array through the socket 15. The high-voltage metal needle electrode plate 5 can also use a high-temperature and high-pressure resistant PCB circuit board. A circuit for the high-voltage metal needle electrode 6 that matches the circular array is drawn on the circuit board, which is 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.

[0034] 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.

[0035] 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 jets can be achieved without this structure, but in the multi-stage plasma jet generating 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.

[0036] 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, and any of a DC power supply, an AC power supply or a pulse power supply can be used to supply power to the high-voltage electrode in the device.

[0037] 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.

[0038] The metal wall ground electrode 8 covers the entire inner wall of the cylinder, and it constitutes the electrode structure for generating ion wind and plasma jet inside the device. At the same time, the metal rectangular mesh ground electrode 4 is grounded through electrical connection, and serves as the annular part in the mesh ring structure for generating ion wind in the primary ion wind driving area, and serves as the ground electrode part of the dielectric barrier discharge generated by plasma and the annular part in the needle ring structure for generating ion wind in the multi-stage ion wind-plasma jet coupling area.

[0039] like Figure 2 As shown, the metal wire mesh high voltage electrode 3 has a circular profile 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.

[0040] 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 barrel metal wall ground electrode 8 and fixed by welding or bonding.

[0041] The metal wire mesh high-voltage electrode 3 and the metal rectangular mesh ground electrode 4 are arranged in parallel to form a wire mesh electrode structure for generating ion wind. The spacing between the two metal meshes is between 8 and 10 mm, which ensures the uniformity of gas discharge between the electrodes. The flow rate of the generated ion wind can reach a maximum value of 1.8 m / s; the flow rate of the ion wind obtained when the electrode spacing exceeds this range is reduced. If the electrode spacing is less than this range, the ionized gas between the electrodes is limited. If the electrode spacing is greater than this range, the discharge conditions between the electrodes are increased and the ionization of the gas is reduced. If the two plates are tilted (not placed in parallel), the voltage between the electrodes will be unstable, the discharge voltage will be distorted, and it is not conducive to the generation of ion wind. This part is the primary ion wind driving area, where the ion wind generated in this area drives the external air to flow in, and pushes the initially ionized gas backward to the multi-stage ion wind-plasma jet coupling area. Through testing, the electrode structure composed of a wire mesh-shaped high-voltage electrode and a grid-shaped ground electrode has a better gas ionization effect and generates a faster ion wind flow rate.

[0042] 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.

[0043] 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.

[0044] The metal wire mesh high-voltage electrode 3 will be at a relatively high temperature (high temperature resistance is required) under high voltage. At the same time, metal materials with low work function are more conducive to the generation of plasma. In this embodiment, the metal wire mesh high-voltage electrode 3 is made of metal tungsten. In theory, any metal material that meets high temperature resistance can be used as the electrode material, such as tungsten copper alloy and metal nickel. However, considering that metal materials with low work function are more conducive to the generation of plasma, tungsten electrode is a better choice. The circular outline diameter D1 of the metal wire mesh high-voltage electrode 3 is 28 mm, the diameter of the metal wire is 0.05 mm, and the gap L1 between adjacent metal wires is 3 mm.

[0045] The metal rectangular mesh ground electrode 4 is made of metal aluminum, and can be made of conductive metals such as metal copper and metal copper alloy to provide a stable ground electrode voltage. The circular outline diameter D2 of the metal rectangular mesh ground electrode 4 is 30 mm, the metal wire diameter is 0.05 mm, and the rectangular mesh side lengths L2 and L3 are 3 mm. The metal wire mesh high-voltage electrode 3 and the metal rectangular mesh ground electrode 4 form a wire mesh structure. When the high-voltage excitation power supply 1 is powered, an ion wind is generated from the metal wire mesh high-voltage electrode 3 to the metal wall ground electrode 8 to drive the airflow and the generated plasma to flow forward.

[0046] In some embodiments, the high-voltage metal needle electrode plate 5 adopts a five-layer annular array, and the diameter of the high-voltage metal needle electrode plate 5 is D3=30mm. In the design of the device, the number of layers can be adjusted according to the actual situation. The spacing between adjacent rings can be reduced to increase the number of layers of the annular array, but it is necessary to ensure that the diameter of the high-voltage metal needle electrode plate 5 is within 40mm, and to ensure that the annular metal needles within a certain range of the inner layer (the innermost layer fails first and slowly diffuses to the outer layer) participate in the generation of plasma and ion wind to avoid failure of the inner metal needles. When the diameter is too large, it exceeds the electrode distance of 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 richer the charged particles and active particles in the generated plasma jet, but the corresponding device requires higher power consumption and higher material requirements for the device.

[0047] In this embodiment, the length difference of the metal needles of adjacent rings is set to 20mm, and the spacing between adjacent rings is l=3mm. In this embodiment, a tungsten needle with a diameter of Φ=0.7mm and a needle tip radius of 70μm is used as the metal needle electrode. Any metal needle with a diameter of less than 0.7mm can 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).

[0048] The range of the distance between adjacent rings is 1.5mm~6mm. The distance between adjacent rings determines the density of each layer of high-voltage metal needle electrodes 6 inside the device. When the distance is too small, the high-voltage metal needle electrodes are dense, the average electric field energy in the internal space of the device increases, and the gas discharge inside the space is weakened. When the distance is too large, the number of layers decreases, the number of levels of multi-stage ion wind driven plasma jets decreases, and the performance of generating plasma jets decreases. In Example 2, the distance between adjacent rings is set to 3mm, which can achieve a five-level ion wind driven plasma jet, and the average discharge power of the high-voltage metal needle electrode is the largest (the overall discharge power of the device is averaged to the metal electrode needle).

[0049] 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 formed by the innermost high-voltage metal needle electrode 6 and the metal wall will no longer discharge to generate plasma.

[0050] In some embodiments, the insulating dielectric ring 7 is made of alumina ceramic material, 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.

[0051] 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.

[0052] The insulating shell 10 is used as the shell of the device and can be made of insulating materials such as plastic and rubber to isolate the internal and external environments and provide a strict airtight environment for the device. At the same time, it can be touched and used by operators.

[0053] The annular magnetic core 9 is embedded in the insulating shell 10, and an axial magnetic field direction can be generated inside the device. Under the impetus of 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 obtained, so as to obtain a more stable plasma jet.

[0054] The annular magnetic core 9 uses an axially magnetized neodymium iron boron magnet; the annular magnetic core 9 can also use a powered spiral coil to control the magnetic field size inside the device by controlling the current, further achieving the effect of controlling the plasma characteristics. However, attention should be paid to the thermal effect of the spiral coil when it is powered on, and the selection of insulating dielectric materials or the installation position should be considered; the insulating material can be made of high-temperature resistant silicone rubber, which can withstand the heat of the coil and maintain its original shape without deformation; Installation position: the annular magnetic core 9 is not embedded in the insulating shell 10, and a long ring-shaped axially magnetized neodymium iron boron magnet is selected and directly wrapped on the outside of the insulating shell 10.

[0055] The metal wall ground electrode 8 is tightly attached to the inner side of the insulating shell 10 of the barrel wall of the device. This part is grounded through a wire to form a ground electrode for a plasma generating dielectric barrier discharge structure and an ion wind generating needle ring structure. The material of the metal ground electrode can be selected from conductive metals such as copper and aluminum.

[0056] Embodiment 3, Another way to achieve multi-stage ion wind driven plasma jet: like Figure 6 As shown, the high-voltage metal needle electrode plate 5 has only two layers of ring structure, and the distance between adjacent rings is set to 3mm; the central high-voltage metal needle electrode 6 is located at the central axis of the device, and the outer layer of high-voltage metal needle electrodes 6 surrounds the central metal ring array and is inserted on the high-voltage metal needle electrode plate 5. Under the excitation of the high-voltage excitation power supply 1, the high-voltage metal needle electrodes 6 of the ring array, the insulating dielectric ring 7, and the metal wall ground electrode 8 form a dielectric barrier discharge structure, and a plasma jet is generated in this area (at Figure 6 (marked in the middle).

[0057] The mutual influence between the electrodes inside the device of Example 2 results in that the space inside some devices is not fully utilized (see Figure 1 Compared with the embodiment 2, the high-voltage metal needle electrodes 6 in this embodiment are all involved in the generation of plasma, while reducing the influence between the electrodes, and the plasma generation efficiency inside the device structure space is higher.

[0058] The high-voltage metal needle electrode 6 on the 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.

[0059] like Figure 7As shown, multiple ion wind propulsion and plasma jet structural units are coupled, and adjacent structural units are combined together at the coupling point by means of inlay insertion, bonding, external fixation, etc. Each structural unit is a first-level ion wind propulsion and plasma jet generator, and a complete plasma jet coupling device is formed through multi-stage coupling. Furthermore, other characteristic structural units can be added on the basis of the coupling structure to optimize the plasma jet device. For example, a structural unit with a conical outlet can be designed at the final jet outlet, so that the plasma jet is more concentrated in a smaller area when it flows out. Such a structure can cope with application scenarios that require high-speed plasma jets and small plasma processing.

[0060] It is highly flexible and can flexibly combine and set the coupling of the plasma jet device according to the application scenario and technical indicators. As long as the coupling structures do not conflict with each other, structural units with characteristics can be designed to meet the needs of different application scenarios.

[0061] In some embodiments, along the airflow direction, a metal rectangular mesh ground electrode 4 is installed on the rear side of the insulating medium ring 7. The high-voltage metal needle electrode 6 not only forms a needle ring structure for generating ion wind with the metal wall ground electrode 8 of the cylinder wall, but also forms a needle mesh structure for generating ion wind with the metal rectangular mesh ground electrode 4, which helps to enhance the ion wind and generate stronger ion wind thrust (the ion wind is marked in the figure), which can effectively increase the gas flow rate inside the device.

[0062] Embodiment 4, The structure of Example 2 is used as the first-stage ion wind propulsion and plasma jet generating unit, and the structural unit of Example 3 is coupled behind the jet outlet 11, and the inner diameter size needs to be consistent. The addition of the first-stage ion wind propulsion and plasma jet area can enhance the plasma jet effect of the device of Example 2.

[0063] Experimental data: During the test, in order to obtain a more obvious plasma jet effect, the plasma jet generating device with a jet outlet diameter of 1 mm and the participation of a gas source was compared. The jet outlet of the device in Example 2 and the conical pipe with a sealed nozzle aperture of 1 mm and a length of 20 mm were used for comparison. Under the excitation of the same 10kV AC voltage, the plasma jets generated by the two devices were photographed and compared by a camera. The plasma jet device with the participation of a gas source was introduced into the air with a gas flow rate of 6L / min, and the maximum gas flow rate was 18.8m / s at the outlet of the gas pipe, and the generated plasma jet could reach 9mm; while the jet length generated by the device in Example 2 could reach 10mm, but the plasma component in the plasma jet was significantly increased, the jet became thinner and more concentrated, and the brightness was also improved to a certain extent; therefore, Example 2 can achieve the plasma jet effect generated by the plasma jet generating device with a gas flow rate of 6L / min without the participation of the gas source equipment.

[0064] In the case of three-level structural unit coupling in Example 3, a single structural unit inside the device can generate an ion wind speed of up to 10m / s, while the maximum ion wind speed generated by the traditional needle ring structure is 8m / s, and the gas flow rate inside the entire coupling structure reaches 25m / s. Similarly, compared with a plasma jet generating device with a jet outlet diameter of 1mm with the participation of a gas source, when air with a gas flow rate of 10L / min is introduced, the maximum gas flow rate is 25.6m / s at the outlet of the gas pipe, and the generated plasma jet can reach 13mm. The jet length generated by the device in Example 3 can reach 15mm, and the plasma ion component in the plasma jet is significantly increased, and the jet becomes thinner and more concentrated. Therefore, Example 3 can achieve the plasma jet effect generated by a plasma jet generating device with a gas flow rate of 10L / min.

[0065] The embodiment of the present invention provides a structure for a plasma jet generating device that does not rely on an external gas carrier device to supply airflow. The problem that conventional plasma generation requires a gas source is solved by driving the plasma jet with multi-stage ion winds, and a structure for driving the plasma jet with multi-stage ion winds is proposed. The ion wind generating area and the plasma jet generating area are rationally planned inside the device, and the two areas are arranged in an alternating manner, each performing its own function and cooperating with each other to ultimately achieve the desired function.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

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 medium ring (7) is in close contact with the metal wall ground electrode (8) and is arranged at intervals starting 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); 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, and 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 ion wind generation area and the plasma generation area are arranged alternately, and the generation of the plasma jet is driven by 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) have the same length, and the needle tips of the high-voltage metal needle electrodes (6) are aligned with the edges of the insulating medium rings (7) at corresponding positions; the high-voltage metal needle electrodes (6) on a single high-voltage metal needle electrode plate (5) and the insulating medium rings (7) at corresponding positions constitute an ion wind propulsion and plasma jet structural unit; a plurality of jet structural units are combined to achieve 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. The needle tip of the high-voltage metal needle electrode (6) is aligned with the edge of the insulating medium ring (7) at the corresponding position, 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 difference in length of the metal needles of adjacent rings is between 20 and 30 mm, and the spacing width between adjacent insulating medium rings (7) is half the difference in length of 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 layer of the high-voltage metal needle electrodes (6) and the inner wall of the cylinder is from 3 mm to 20 mm.

6. The plasma jet device based on ion wind drive 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 based on ion wind drive according to claim 1, characterized in that: The high-voltage metal needle electrode plate (5) comprises an insulating mesh plate (13), wherein a plurality of layers of annular conductive circuits (14) are provided inside the insulating mesh plate (13), and a plug hole (15) is provided on the insulating mesh plate (13) for inserting the high-voltage metal needle electrode (6) and connecting to the conductive circuit (14), wherein 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 connected to a high-voltage excitation power source (1) via the conductive circuit (14), and the insulating mesh plate (13) uses the conductive circuit (14) as a frame, and the remaining portion is provided with air-permeable mesh holes (16); Alternatively, the high-voltage metal needle electrode plate (5) is a PCB circuit board, on which a circuit for matching the annular array of high-voltage metal needle electrodes (6) is drawn, which is connected to a high-voltage excitation power source (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 driven by ion wind according to claim 1, characterized in that: The outer wall of the cylinder is provided with an insulating shell (10), and a ring-shaped 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 axis in the cylinder to form a rotating jet; the ring-shaped magnetic core (9) is an axially magnetized neodymium iron boron magnet or a energized spiral coil.

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