Device and method for regulating and controlling plasma jet form based on third electrode

Abstract

The invention discloses a plasma jet form regulation and control device and method based on a third electrode, and the device comprises a jet pipe which is used for guiding a working gas to flow, forming a plasma jet channel, and generating a plasma jet at an outlet of the jet pipe; the high-voltage electrode is arranged in the jet pipe and used for applying discharge voltage to generate plasma in the jet pipe; the ground electrode is arranged opposite to the high-voltage electrode and is matched with the high-voltage electrode to form a discharge area in the jet pipe; the third electrode is arranged outside the outlet of the jet pipe and is used for applying an extra electric field to regulate and control the form of the plasma jet and improve the propagation characteristic of the plasma jet; wherein the third electrode applies an extra electric field to enhance the propagation distance of ionization waves in the axial direction and the radial direction, and increase the plasma coverage range, so that the plasma jet treatment area is increased, and the plasma jet application cost is effectively reduced.

Description

Technical Field

[0001] The present invention relates to intelligent manufacturing processing technology, and in particular to a plasma jet morphology control device and method. Background Art

[0002] Plasma is a complex system composed of active particles such as electrons, ions, free radicals, photons, etc. It has the characteristics of high energy, high activity, high selectivity, etc., and can realize a variety of physical and chemical processes, such as ionization, excitation, dissociation, oxidation, reduction, etc. Plasma jet is an atmospheric pressure non-equilibrium plasma source that can separate the plasma generation area and the working area in space. It has the advantages of low temperature, mild discharge, and high active particle production. It can be applied to material surface treatment, biomedicine, environmental engineering and other fields.

[0003] The morphology of the jet determines the range of the material surface that it can cover and process, and also affects its contact time with the material surface and the concentration of active particles. The larger the coverage area, the farther the jet can propagate and expand, better maintain its stability and activity, and achieve better treatment effects in different fields. Therefore, increasing the effective area of ​​the plasma jet will help its further application in the future. Domestic and foreign scholars have conducted in-depth research on plasma jets and proposed a variety of methods to increase the length of plasma jets, such as: designing new electrode structures, increasing the amplitude and frequency of the discharge voltage, and increasing the working gas flow rate. However, the special design of the electrode structure is not universal. The increase in discharge voltage and frequency will increase energy consumption, and increasing the working gas flow rate will increase gas consumption and cost. Finding a simple and reliable method to increase the coverage area of ​​plasma jets will have a good promoting effect on its further application.

[0004] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0005] The main purpose of the present invention is to solve the problems existing in the above-mentioned background technology and to provide a plasma jet morphology control device and method based on a third electrode.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A plasma jet morphology control device based on a third electrode, comprising:

[0008] A jet tube, which is used to guide the working gas to flow and form a plasma jet channel, and generate a plasma jet at the jet tube outlet;

[0009] a high voltage electrode, which is disposed inside the jet tube and is used to apply a discharge voltage to generate plasma in the jet tube;

[0010] A ground electrode, which is arranged opposite to the high-voltage electrode and cooperates with the high-voltage electrode to form a discharge area in the jet tube;

[0011] The third electrode is arranged outside the jet tube outlet and is used to apply an additional electric field to regulate the shape of the plasma jet and improve its propagation characteristics; wherein the third electrode applies an additional electric field to enhance the axial and radial propagation distances of the ionization wave, increase the plasma coverage, and thus increase the plasma jet processing area.

[0012] Further, the third electrode is an electrode opposite to the jet tube outlet and may be in a ring shape, but the present invention is not limited thereto.

[0013] Furthermore, it also includes a jet chamber, the outlet of the jet tube is located in the jet chamber, the jet chamber has an exhaust structure, the gas ejected from the outlet of the jet tube forms a loop airflow flowing toward the outlet of the jet tube in the closed discharge environment of the jet chamber, and the exhaust structure connects the interior of the jet chamber with the external atmospheric pressure.

[0014] Furthermore, it also includes a gas buffer chamber, which is arranged at the inlet of the jet tube or connected to the inlet of the jet tube through a gas channel, and the gas buffer chamber is provided with a rare gas inlet and a doping gas inlet.

[0015] Furthermore, the working gas is a rare gas or a rare gas containing a small amount of doping gas.

[0016] Furthermore, the material of the jet tube may be quartz glass or alumina ceramics, but the present invention is not limited thereto.

[0017] Furthermore, the high voltage electrode, the ground electrode, and the third electrode are made of conductive materials, which may be tungsten needles, copper rods, or stainless steel rods, but the present invention is not limited thereto.

[0018] Furthermore, the discharge voltage applied between the high voltage electrode and the ground electrode is an alternating voltage or a pulse voltage.

[0019] Furthermore, the ground electrode, the high voltage electrode, and the third electrode adopt a single electrode, a double electrode, or a multi-electrode structure.

[0020] A method for regulating the generation characteristics of a plasma jet based on a third electrode uses the plasma jet morphology regulating device to apply an additional electric field through the third electrode to enhance the axial and radial propagation distances of the ionization wave, increase the plasma coverage, and thus increase the plasma jet processing area.

[0021] The present invention has the following beneficial effects:

[0022] The present invention proposes a plasma jet morphology control device and method based on a third electrode, which controls the plasma jet morphology by increasing the electric field of the third electrode, thereby increasing the effective area of ​​the plasma jet at a low cost.

[0023] The new jet proposed in the previous study starts with the basic mechanism, and realizes the radial propagation of the plasma jet by directly regulating the flow field facets, diffusion trend, and gas component ratio changes of the gas outflow jet nozzle. In the present invention, based on the previous research, the inventor further proposed to use a third electrode to apply an additional electric field to assist in enhancing the axial and radial propagation distance of the ionization wave, and to enhance the plasma coverage by adjusting the structure of the third electrode, thereby achieving a larger plasma jet treatment area and effectively reducing the application cost of the plasma jet.

[0024] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the plasma jet generation effect without the third electrode in the prior art.

[0026] Figure 2 It is a schematic structural diagram of a plasma jet morphology control device based on a third electrode according to an embodiment of the present invention, illustrating the plasma jet effect with the third electrode. DETAILED DESCRIPTION

[0027] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0028] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

[0029] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] Experimental studies have found that plasma jets are mainly formed by the rapid propagation of a series of "bullet-shaped" ionization waves. The propagation of "plasma bullets" is closely related to the formation of metastable particles and charge density in rare gases, so adjusting the distribution of metastable particles and charge density in the jet is the key to changing the morphology of plasma jets. The distribution of metastable particles is closely related to the gas composition and gas flow field, so adjusting the gas composition and flow field distribution is an important method to change the morphology of plasma jets.

[0032] See also Figure 2 The embodiment of the present invention provides a plasma jet morphology control device based on a third electrode, comprising: a jet tube 1, which is used to guide the flow of working gas and form a plasma jet channel, and generate a plasma jet 10 at the outlet of the jet tube 1; a high-voltage electrode 2, which is arranged inside the jet tube 1 and is used to apply a discharge voltage to generate plasma in the jet tube 1; a ground electrode 3, which is arranged opposite to the high-voltage electrode 2 and cooperates with the high-voltage electrode 2 to form a discharge area in the jet tube 1; a third electrode 4, which is arranged outside the outlet of the jet tube 1 and is used to apply an additional electric field to control the morphology of the plasma jet and improve its propagation characteristics; wherein the third electrode 4 applies an additional electric field to enhance the propagation distance of the ionization wave in the axial and radial directions, increase the plasma coverage range, and thus increase the plasma jet processing area.

[0033] The solution of regulating the plasma jet by the third electrode proposed in the present invention can greatly increase the effective area of ​​the plasma jet only by the third electrode without increasing the working gas consumption, thereby effectively reducing the application cost of the plasma jet in industry.

[0034] See also Figure 2In a preferred embodiment, the third electrode 4 is a ring electrode opposite to the outlet of the jet tube 1. The third electrode 4 may also adopt other shapes according to application requirements, such as square, triangle, dot array, etc., which are not limited in the present invention.

[0035] See also Figure 2 In a preferred embodiment, it further comprises a jet chamber 5, the outlet of the jet tube 1 is located in the jet chamber 5, the jet chamber 5 has an exhaust structure 6, the gas ejected from the outlet of the jet tube 1 forms a looping airflow flowing toward the outlet of the jet tube 1 in the closed discharge environment of the jet chamber 5, and the exhaust structure 6 connects the inside of the jet chamber 5 with the outside atmospheric pressure. By setting the jet chamber 5 to introduce a relatively closed space, the gas ejected from the outlet of the jet tube 1 forms a looping airflow flowing toward the outlet of the jet tube 1 in the space, which is conducive to forming a large-area diffuse plasma jet at a low cost.

[0036] See also Figure 2 In a preferred embodiment, a gas buffer chamber 7 is further included. The gas buffer chamber 7 is arranged at the inlet of the jet tube 1 or connected to the inlet of the jet tube 1 through a gas channel. The gas buffer chamber 7 is provided with a rare gas inlet 8 and a doping gas inlet 9. The function of the gas buffer chamber is to allow the rare gas and the doping gas to be fully mixed. In addition, the present invention can also use a T-shaped tube directly to achieve the effect of fully mixing the two gases in the gas path without using a gas buffer chamber.

[0037] In some embodiments, the working gas may be a rare gas or a rare gas containing a small amount of dopant gas.

[0038] In some embodiments, the material of the jet tube 1 may be quartz glass or alumina ceramics, but the present invention is not limited thereto.

[0039] In some embodiments, the high voltage electrode 2, the ground electrode 3, and the third electrode 4 are made of conductive materials, which may be tungsten needles, copper rods, or stainless steel rods, and the present invention does not limit this.

[0040] In some embodiments, the discharge voltage applied between the high voltage electrode 2 and the ground electrode 3 may be an alternating voltage (including radio frequency, etc.) or a pulse voltage.

[0041] In some embodiments, the ground electrode 3, the high voltage electrode 2, and the third electrode 4 may adopt a single electrode, a double electrode, or a multi-electrode structure.

[0042] An embodiment of the present invention also provides a method for regulating the generation characteristics of a plasma jet based on a third electrode. Using the plasma jet morphology control device of any of the aforementioned embodiments, an additional electric field is applied through the third electrode to enhance the axial and radial propagation distances of the ionization wave, thereby increasing the plasma coverage range and thus increasing the plasma jet processing area.

[0043] The present invention proposes to introduce a third electrode to modulate the electric field to enhance the scale of the diffuse plasma jet. The scale of plasma jet generation under the conditions without and with the third electrode is compared. Figure 1 and Figure 2 shown.

[0044] The new jet proposed by the inventor in the previous study starts from the basic mechanism, and realizes the radial propagation of the plasma jet by directly regulating the flow field facets, diffusion trend, and gas component ratio changes of the gas outflow jet nozzle. In the present invention, based on the previous research, the inventor further proposes to use a third electrode to apply an additional electric field to assist in enhancing the axial and radial propagation distance of the ionization wave, and enhances the plasma coverage by adjusting the structure of the third electrode, thereby achieving a larger plasma jet processing area and effectively reducing the application cost of the plasma jet.

[0045] In the present invention, the voltage waveform, frequency and positive and negative polarity applied by the electrode structure are not limited, and a nanosecond pulse voltage waveform is preferred, and a positive polarity voltage is applied to the anode. The electrode structure is not limited, and can be a single electrode, a double electrode and a multi-group electrode structure. The size of the electrode structure is not limited. The cross-sectional shape of the electrode structure is not limited, and can be circular, square, polygonal, etc., preferably circular. The material of the jet tube is not limited, and it only needs to be a heat-resistant material, such as quartz glass, alumina ceramics, etc. The working gas flowing through the jet tube is a rare gas or a rare gas doped with a small amount of other gases. The flow rate of the working gas is not limited. The discharge environment of the plasma jet is not limited.

[0046] The idea of ​​the present invention is to increase the effective area of ​​the plasma jet by regulating the plasma jet through the third electrode. Under any form of power supply parameters, electrode structure parameters, and working gas parameters, the scheme of using the third electrode to regulate the plasma jet and increase the effective area of ​​the plasma jet is within the protection scope of the present invention.

[0047] The specific power supply parameters of the embodiment of the present invention are not limited, and can be any plasma power supply of waveform such as AC tube, pulse source, RF source, etc., and the voltage waveform is not limited. The specific electrode structure parameters include unlimited number of electrodes, unlimited size, unlimited material, and unlimited positive and negative polarity. The specific material, size, and shape of the jet tube are not limited. The working gas parameters are not limited, including unlimited rare gas types, unlimited doping gas type ratios, unlimited flow rates, and unlimited discharge space environments.

[0048] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A plasma jet morphology control device based on a third electrode, characterized in that: include: A jet tube, which is used to guide the working gas to flow and form a plasma jet channel, and generate a plasma jet at the jet tube outlet; a high voltage electrode, which is disposed inside the jet tube and is used to apply a discharge voltage to generate plasma in the jet tube; A ground electrode, which is arranged opposite to the high-voltage electrode and cooperates with the high-voltage electrode to form a discharge area in the jet tube; The third electrode is arranged outside the jet tube outlet and is used to apply an additional electric field to regulate the shape of the plasma jet and improve its propagation characteristics; wherein the third electrode applies an additional electric field to enhance the axial and radial propagation distances of the ionization wave, increase the plasma coverage, and thus increase the plasma jet processing area.

2. The plasma jet morphology control device according to claim 1, characterized in that: The third electrode is an electrode opposite to the outlet of the jet tube.

3. The plasma jet morphology control device according to claim 1 or 2, characterized in that: It also includes a jet chamber, the outlet of the jet tube is located in the jet chamber, the jet chamber has an exhaust structure, the gas ejected from the outlet of the jet tube forms a circular airflow flowing toward the outlet of the jet tube in the closed discharge environment of the jet chamber, and the exhaust structure connects the interior of the jet chamber with the external atmospheric pressure.

4. The plasma jet morphology control device according to any one of claims 1 to 3, characterized in that: It also includes a gas buffer chamber, which is arranged at the inlet of the jet tube or connected to the inlet of the jet tube through a gas channel, and the gas buffer chamber is provided with a rare gas inlet and a doping gas inlet.

5. The plasma jet morphology control device according to any one of claims 1 to 4, characterized in that: The working gas is a rare gas or a rare gas containing a small amount of doping gas.

6. The plasma jet morphology control device according to any one of claims 1 to 5, characterized in that: The high voltage electrode, the ground electrode, and the third electrode are made of conductive materials.

7. The plasma jet morphology control device according to any one of claims 1 to 6, characterized in that: The discharge voltage applied between the high voltage electrode and the ground electrode is an alternating voltage or a pulse voltage.

8. The plasma jet morphology control device according to any one of claims 1 to 7, characterized in that: The ground electrode, the high voltage electrode, and the third electrode adopt a single electrode, a double electrode, or a multi-electrode structure.

9. A method for controlling the generation characteristics of a plasma jet based on a third electrode, characterized in that: Using the plasma jet morphology control device as described in any one of claims 1 to 8, an additional electric field is applied through the third electrode to enhance the axial and radial propagation distances of the ionization wave, increase the plasma coverage range, and thus increase the plasma jet processing area.

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