阅读说明：本技术 电场增强的等离子体放电装置及利用该装置增强电场的方法 (Electric field enhanced plasma discharge device and method for enhancing electric field by using same ) 是由 唐诗雅 关银霞 李栖楠 王世强 牟善军 牟洪祥 刘全桢 于 2020-06-18 设计创作，主要内容包括：本发明涉及低温等离子体技术领域,公开了一种电场增强的等离子体放电装置及利用该装置增强电场的方法,该装置包括：同轴设置的等离子体反应管(4)、中心高压电极(1)和金属线圈(2)以及紧贴于等离子体反应管(4)外壁的接地电极(3)；所述金属线圈(2)设置于所述中心高压电极(1)与所述接地电极(3)的放电间隙内。本发明提供的等离子体放电装置能够增强局部电场,一方面降低等离子体放电起始电压,保障等离子体反应器安全稳定长周期运行。另一方面电场增强,有助于提高等离子体产生效率。(The invention relates to the technical field of low-temperature plasma, and discloses an electric field enhanced plasma discharge device and a method for enhancing an electric field by using the same, wherein the device comprises: the plasma reaction tube (4), the central high-voltage electrode (1), the metal coil (2) and the grounding electrode (3) are coaxially arranged, and the grounding electrode is tightly attached to the outer wall of the plasma reaction tube (4); the metal coil (2) is arranged in a discharge gap between the central high-voltage electrode (1) and the grounding electrode (3). The plasma discharge device provided by the invention can enhance the local electric field, reduce the plasma discharge initial voltage on one hand, and ensure the safe and stable long-period operation of the plasma reactor. On the other hand, the electric field is enhanced, which is beneficial to improving the plasma generation efficiency.)

1. An electric field enhanced plasma discharge apparatus, comprising:

the plasma reaction tube (4), the central high-voltage electrode (1), the metal coil (2) and the grounding electrode (3) are coaxially arranged, and the grounding electrode is tightly attached to the outer wall of the plasma reaction tube (4);

the metal coil (2) is arranged in a discharge gap between the central high-voltage electrode (1) and the grounding electrode (3).

2. The electric field enhanced plasma discharge device according to claim 1, wherein the metal coil (2) is arranged around the central high voltage electrode (1).

3. The electric field enhanced plasma discharge device according to claim 2, wherein the inner diameter of the metal coil (2) is larger than or equal to the outer diameter of the central high voltage electrode (1).

4. The electric field enhanced plasma discharge device according to claim 1, wherein an inner diameter of the metal coil (2) is smaller than or equal to an inner diameter of the plasma reaction tube (4).

5. The electric field enhanced plasma discharge apparatus of any of claims 1 to 4, wherein the pitch of the metal coil is 0.2-15 mm.

6. The electric-field-enhanced plasma discharge apparatus according to any one of claims 1 to 4, wherein the wire diameter of the metal coil is 0.05 to 3 mm.

7. The electric field enhanced plasma discharge device according to any one of claims 1 to 4, wherein the electrical conductivity of the central high voltage electrode (1), the ground electrode (3) and the metal coil (2) is 10 at 25 ℃⁵-10⁸S/m。

8. The electric field enhanced plasma discharge device according to claim 7, wherein the central high voltage electrode (1), the ground electrode (3) and the metal coil (2) are of a high temperature resistant conductive metal.

9. The electric-field-enhanced plasma discharge device according to any one of claims 1 to 4, wherein the surface of the metal coil (2) is smooth or threaded.

10. The electric-field-enhanced plasma discharge device according to any one of claims 1 to 4, wherein a catalyst is attached to a surface of the metal coil (2).

11. The electric-field-enhanced plasma discharge device according to any one of claims 1 to 4, wherein the plasma reaction tube (4) is an insulating medium tube;

preferably, the insulating medium is quartz, ceramic, corundum, or polytetrafluoroethylene.

12. The electric-field-enhanced plasma discharge apparatus according to any one of claims 1 to 4, wherein the central high voltage electrode (1) is tubular or rod-shaped.

13. The electric-field-enhanced plasma discharge device according to claim 12, wherein the tubular central high voltage electrode is an insulating dielectric tube filled with a conductive metal powder;

preferably, the insulating medium pipe is internally provided with a conductive metal rod;

preferably, the insulating medium pipe is internally provided with a conductive metal pipe;

preferably, the insulating medium tube is made of quartz, ceramic, corundum or polytetrafluoroethylene.

14. A method of electric field enhancement, characterized in that it employs a plasma discharge device as claimed in any one of claims 1 to 13.

Technical Field

The invention relates to the technical field of low-temperature plasma, in particular to an electric field enhanced plasma discharge device and a method for enhancing an electric field by using the same.

Background

The low-temperature plasma technology is a technology for generating high-chemical-activity particles (including electrons, positive and negative ions, neutral particles and the like) by applying a high-voltage electric field to gas to cause gas ionization, and the high-chemical-activity particles are utilized to participate in chemical reaction. On the other hand, a high-voltage electric field can also generate high-speed particles and has high energy at the moment of annihilation of positive and negative ions. These characteristics make low temperature plasma technology have wide application prospects. For example, plasma sterilization and disinfection, which utilizes plasma technology to generate active free radicals and electrons or ions with high kinetic energy to destroy cell or virus structures, thereby achieving the effect of sterilization and disinfection; modifying the surface of a plasma material, bombarding the surface of a solid by using particles with certain energy, and inducing surface atoms or molecules to generate new chemical bonds; in addition, the plasma treatment of toxic and harmful gases and the like utilize the oxidation-reduction reaction between the high-activity particles and pollutant gas molecules to realize harmless emission. Aiming at the increasingly serious environmental problems, the plasma method generated by ionizing gas by using an electric field is an economic and efficient method for degrading low-concentration atmospheric Volatile Organic Compounds (VOCs), and can also be used for decomposing hydrogen sulfide by using plasma, treating dust, desulfurizing and denitrating flue gas, treating odor and the like.

In the above plasma technology, the strength and distribution of the electric field directly affect the generation and operating efficiency of the plasma. The strength and distribution of the electric field is directly determined by the power supply and the plasma generator structure (i.e., the discharge form). The power source is related to the influence factors such as voltage, frequency and power source form (such as direct current, high-frequency alternating current, pulse and the like). However, in a large device for practical application, the structure of the plasma generator is difficult to adjust, the driving power supply is fixed, and the adjustable range of voltage and frequency is limited. When the plasma processing device with limited voltage regulation can not meet the requirements of practical application under the condition of complicated actual working conditions of components, such as coking or scaling adhesion on the surface of a reactor, larger concentration fluctuation of the object to be processed and the like.

Disclosure of Invention

The invention aims to overcome the problems in the prior art, and provides an electric field enhanced plasma discharge device, wherein a suspended conductor is added in an original electric field, the distance between a positive electrode and a negative electrode is reduced, a distorted electric field is formed, the electric field intensity is locally improved, and the plasma discharge starting voltage is reduced, so that the adjustable voltage interval in the original design range of a power supply is relatively enlarged, and the electric field enhanced plasma discharge device is suitable for the condition of large concentration fluctuation of a to-be-treated object.

In order to achieve the above object, an aspect of the present invention provides an electric field enhanced plasma discharge apparatus, comprising: the plasma reaction tube, the central high-voltage electrode, the metal coil and the grounding electrode are coaxially arranged, and the grounding electrode is tightly attached to the outer wall of the plasma reaction tube; the metal coil is arranged in a discharge gap between the central high-voltage electrode and the grounding electrode.

Preferably, the metal coil is arranged around the central high voltage electrode.

Preferably, the inner diameter of the metal coil is greater than or equal to the outer diameter of the central high voltage electrode.

Preferably, the inner diameter of the metal coil is less than or equal to the inner diameter of the plasma reaction tube.

Preferably, the pitch of the metal coil is 0.2-15 mm.

Preferably, the wire diameter of the metal coil is 0.05-3 mm.

Preferably, the central high voltage electrode is grounded at 25 DEG CThe conductivity of the electrode and the metal coil is 10⁵-10⁸S/m。

Preferably, the central high-voltage electrode, the grounding electrode and the metal coil are made of high-temperature-resistant conductive metal.

Preferably, the surface of the metal coil is smooth or threaded.

Preferably, a catalyst is attached to the surface of the metal coil.

Preferably, the plasma reaction tube is an insulating medium tube.

Preferably, the insulating medium is quartz, ceramic, corundum, or polytetrafluoroethylene.

Preferably, the central high voltage electrode is tubular or rod-shaped.

Preferably, the tubular central high-voltage electrode is an insulating medium tube filled with conductive metal powder.

Preferably, the insulating medium pipe is internally provided with a conductive metal rod.

Preferably, the insulating medium pipe is internally provided with a conductive metal pipe.

Preferably, the insulating medium tube is made of quartz, ceramic, corundum or polytetrafluoroethylene.

In a second aspect, the present invention provides a method for enhancing an electric field, wherein the method employs the plasma discharge device of the present invention.

By the technical scheme, under the conditions that the driving power supply is fixed and the adjustable range of voltage and frequency is limited, on one hand, the initial discharge voltage can be reduced by adding the suspension conductor coil, and the long-period safe and stable operation of the reactor and the power supply is ensured; on the other hand, the wire diameter, the outer diameter or the screw pitch of the suspension conductor coil can be adjusted to locally enhance the strength of an electric field and change the distribution of the electric field, so that the method is suitable for the condition that the concentration of the waste gas to be treated fluctuates greatly, and the concentration of active particles generated by the plasma is improved, thereby improving the overall treatment efficiency of the plasma reactor.

Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.

Drawings

FIG. 1 is a diagram of electric fields in the prior art;

FIG. 2 is a schematic structural diagram of a plasma discharge device according to an embodiment of the present invention;

FIG. 3 is a schematic view of a plasma discharge apparatus according to another embodiment of the present invention;

FIG. 4 is a schematic view of a plasma discharge apparatus according to another embodiment of the present invention;

FIG. 5 is a schematic diagram showing simulation of electrostatic field intensity of the plasma discharge apparatus in example 1 of the present invention;

FIG. 6 is a schematic diagram showing an electrostatic field strength simulation of a plasma discharge apparatus according to embodiment 2 of the present invention;

FIG. 7 is a schematic diagram showing an electrostatic field strength simulation of a plasma discharge apparatus according to embodiment 3 of the present invention;

FIG. 8 is a schematic diagram showing an electrostatic field strength simulation of a plasma discharge apparatus according to embodiment 4 of the present invention;

FIG. 9 is a schematic diagram showing an electrostatic field strength simulation of a plasma discharge apparatus according to example 5 of the present invention;

fig. 10 is a schematic diagram showing an electrostatic field strength simulation of the plasma discharge apparatus in embodiment 6 of the present invention.

Description of the reference numerals

1. Center high-voltage electrode 2 and metal coil

3. Grounding electrode 4 and plasma reaction tube

5. Quartz tube 6, metal powder

7. Metal bar 8, gas inlet

9. Gas outlet

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In the present invention, the use of directional terms such as "upper, lower, left, right" generally means upper, lower, left, right in the drawings, and "inner, outer" means inner and outer of the corresponding structures, unless otherwise specified.

In the invention, the waste gas comprises Volatile Organic Compounds (VOCs) which are organic compounds with saturated vapor pressure at normal temperature of more than 70Pa and boiling point at normal pressure of not more than 260 ℃, and the detected VOCs comprise more than 150 kinds, in addition, hydrogen sulfide, dust treatment, flue gas desulfurization and denitration, foul smell and the like.

In a first aspect, the present invention provides an electric field enhanced plasma discharge device comprising: the plasma reaction tube 4, the center high-voltage electrode 1 and the metal coil 2 which are coaxially arranged, and the grounding electrode 3 which is tightly attached to the outer wall of the plasma reaction tube 4; the metal coil 2 is arranged in a discharge gap between the central high-voltage electrode 1 and the grounding electrode 3. Fig. 2 is a schematic structural diagram of a plasma discharge device according to an embodiment of the present invention. As shown in fig. 2, the center high voltage electrode 1 is disposed coaxially with the plasma reaction tube 4, the ground electrode 3 is closely attached to the outer wall of the plasma reaction tube 4, and the metal coil 2 is disposed in the discharge gap between the center high voltage electrode 1 and the ground electrode 3.

The electric field enhanced plasma discharge device provided by the invention has the advantages that the metal coil is additionally arranged in the discharge gap for applying the driving voltage between the high-voltage electrode and the grounding voltage electrode, so that the electric field is distorted, the initial discharge voltage can be reduced, and the local electric field can be further enhanced. The electric field is generally calculated by equation 1.

In formula 1, E represents the average electric field between the positive and negative electrodes, and the unit is V/m; u is applied voltage and has a unit of V; r is the distance between the electrode plates in m. FIG. 1 is a diagram of electric fields in the prior art; as shown in fig. 1, when no other conductor exists in the electric field, the electric field strength can be calculated by formula 1. When a conductor with a certain diameter d exists in the discharge space, the interior of the conductor is polarized (the conductor is still neutral, i.e. the charge is 0), and the corresponding upper and lower surfaces are enriched with charges to form an upper and a lower r₁And r₂Two local electric fields with corresponding voltages of U₁And U₂Wherein r is₁And r₂Are all less than r, U₁And U₂Equal to U. According to the formula 1, since the distance is shortened, the electric field E in the upper and lower two regions divided by the metal conductor₁And E₂Are all greater than E.

In the specific implementation of the present invention, in order to further utilize the existing device to achieve the purposes of enhancing the local electric field and increasing the concentration of active particles generated by gas ionization, the operating parameters of voltage and frequency are mainly fixed in the actual operation process (or because the existing device is adopted, the parameters of the discharge gap of the plasma generator and the voltage regulation range U and the frequency f of the matching power supply are fixed values), and in order to meet the requirements of different waste gases to be treated in the specific implementation, on the basis of utilizing the existing coaxially arranged plasma generator, the local electric field can be enhanced by adding the suspended metal coil in the discharge gap.

In the present invention, it is preferable that the metal coil 2 is disposed around the central high voltage electrode 1.

In the present invention, it is preferable that the inner diameter of the metal coil 2 is greater than or equal to the outer diameter of the central high voltage electrode 1. As shown in fig. 3, the central high voltage electrode is a metal rod 7, the metal coil 2 is disposed around the metal rod 7, the inner diameter of the metal coil 2 is larger than the outer diameter of the metal rod 7, and the metal coil 2 is suspended in the discharge gap between the high voltage and the ground electrode without being connected to the line. In the specific embodiment of the present invention, when the metal coil 2 is wound around the central high voltage electrode 1, the inner diameter of the metal coil 2 may also be the same as the outer diameter of the central high voltage electrode 1, that is, the metal coil 2 is directly wound around the central high voltage electrode, at this time, in order to ensure that the metal coil 2 is not connected into the line, the central high voltage electrode is an insulating tube filled with a conductor, for example, quartz, ceramic, a corundum tube or polytetrafluoroethylene may be used as the insulating tube, and a metal powder is filled in the insulating tube as the central high voltage electrode; in another embodiment of the present invention, quartz, ceramic, corundum tube or teflon tube can be used as the insulating tube, and a metal rod is embedded in the insulating tube to form a central high voltage electrode, as shown in fig. 4; in another embodiment of the present invention, the central high voltage electrode is also formed by embedding a metal tube in an insulating tube.

The pitch of the metal coil is less than the length of the discharge area, and in the invention, the pitch of the metal coil 2 is preferably 0.2-15 mm; more preferably, the pitch of the metal coil 2 is 3-10 mm.

The wire diameter of the metal coil is smaller than the discharge gap, and in the present invention, the wire diameter of the metal coil 2 is preferably 0.05-3 mm; more preferably, the wire diameter of the metal coil 2 is 0.3 to 1.5 mm.

The suspension mode can be realized by a coaxial or non-coaxial arrangement mode, specifically, when the coaxial arrangement mode is adopted, the center of the center high voltage electrode is coincided with the center of the metal coil, and the distance R from the center of the center high voltage electrode to a fixed point on the inner wall of the plasma reaction tube₁Greater than or equal to the distance R from the center of the metal coil to the point₂. In one embodiment of the invention, the outer diameter of the central high voltage electrode is 10mm, the inner diameter of the plasma reaction tube is 11.6mm, the discharge gap is 0.8mm, the outer diameter of the metal coil is 11.2mm, the wire diameter of the metal coil is 0.4mm, the two are coaxially arranged, and in the same longitudinal interface, the distance between the metal coil and the inner surface of the high voltage electrode and the inner surface of the plasma reaction tube is 0.2 mm. When the metal coil and the central high-voltage electrode are arranged non-coaxially, the inner diameter of the metal coil is larger than the outer diameter of the central high-voltage electrode, and the metal coilIs smaller than the inner diameter of the plasma reaction tube.

The electrical conductivity of the center high-voltage electrode, the ground electrode, and the metal coil is not particularly limited, and may be such that the strength of the electric field and the concentration of active particles generated by gas ionization can be affected, and in the present invention, the electrical conductivity of the center high-voltage electrode, the ground electrode, and the metal coil is preferably 10 at 25 ℃⁵-10⁸S/m, more preferably, the center high voltage electrode, the ground electrode and the metal coil have a conductivity of 10 at 25 DEG C⁷-10⁸S/m。

In the present invention, preferably, the central high voltage electrode, the ground electrode and the metal coil are made of high temperature resistant conductive metal; further preferably one or more of platinum, rhodium, palladium, gold, copper, tungsten, iron and stainless steel containing nickel and titanium; still more preferably iron, copper or tungsten.

In the present invention, it is preferable that the surface of the metal coil 2 is smooth or has a screw thread.

The thread is not particularly limited and may have any shape. Those skilled in the art can select the use as actually required.

In the present invention, preferably, a catalyst is attached to the surface of the metal coil 2, and in the embodiment of the present invention, in order to further promote/facilitate the degradation of the exhaust gas, the surface of the metal coil 2 is threaded, so as to further improve the treatment efficiency of the exhaust gas by loading the catalyst.

The type of the supportable catalyst is not particularly limited, and the catalyst may be one capable of further promoting the exhaust gas treatment, and may be, for example, a metal oxide, a metal sulfide, a silicide, or the like, and may be one capable of increasing the exhaust gas treatment rate or reducing side reactions. For example, it may be an Ag catalyst for degrading benzene series, a Pd catalyst for degrading hydrocarbons, or a catalyst for degrading H₂S Ni catalyst, etc., but not limited thereto, and those skilled in the art can select and use them as needed according to the concentration of the contaminant molecules to be treated and the main content of each component therein, and in the present invention,preferably, the catalyst may be a catalyst loaded with one or more active ingredients of Ag, Cu, Ni, Pt, Pd, Ti, Cr, Au, and oxides thereof. Specifically, for example, one active ingredient may be loaded alone, 2 active ingredients may be loaded selectively, or 3 or more active ingredients may be loaded selectively as needed. In one embodiment of the invention, Ag and TiO are selected to be loaded separately₂The active ingredients are used; in another embodiment of the present invention, Ni-loaded and Cr-loaded active ingredients are selected for use; in another embodiment of the present invention, the Pd active component, the Pt active component and the TiO are selectively supported₂The active ingredient is used.

The plasma reaction tube is not particularly limited, and may be various reaction tubes having insulating properties, which are conventional in the art, and in the present invention, it is preferable that the plasma reaction tube 4 is an insulating medium tube; more preferably, the insulating medium is quartz, ceramic, corundum, or polytetrafluoroethylene. In one embodiment of the invention, the plasma reaction tube is a quartz tube; in another embodiment of the present invention, the plasma reaction tube is a corundum tube.

The shape of the central high voltage electrode is not particularly limited, and may be various shapes conventionally used in the art, and in the present invention, it is preferable that the central high voltage electrode 1 is a tube or a rod.

The tubular high-voltage electrode is not particularly limited, and may be various tubes with insulating property, which are conventional in the art, and in the present invention, the tubular central high-voltage electrode 1 is preferably an insulating medium tube; and the insulating medium tube is filled with conductive metal powder.

The insulating medium pipe is not particularly limited, and in the present invention, the insulating medium pipe is preferably a quartz, ceramic, corundum, or polytetrafluoroethylene pipe. In one embodiment of the invention, the insulating medium tube is a quartz tube; in another embodiment of the invention, the insulating medium pipe is a corundum pipe.

The conductive metal powder is not particularly limited, and in the present invention, it is preferable that the conductive metal powder is one or more of iron, copper, or magnesium. Fig. 4 is a schematic view of a plasma discharge device according to another embodiment of the present invention. As shown in fig. 4, the plasma discharge device of the present invention is provided with a central high voltage electrode composed of an insulating dielectric tube 5 and metal powder 6 filled therein. In the embodiment of the invention, iron powder is selected as metal conductive powder and filled in an insulating medium tube (specifically a quartz tube) to be used as a central high-voltage electrode. One skilled in the art can also select other metal powder with conductive performance to be filled in the insulating medium tube as the central high-voltage electrode for use according to the requirement.

In the present invention, preferably, the central high voltage electrode 1 is an insulating dielectric tube with a conductive metal rod therein. In another embodiment of the invention, quartz, ceramic, corundum tube or polytetrafluoroethylene can be used as an insulating tube, and a metal rod is embedded in the insulating tube to form a central high-voltage electrode; in yet another embodiment of the present invention, a metal tube is embedded within the insulating tube as the central high voltage electrode.

The material of the metal rod or the metal pipe embedded in the insulating pipe is not particularly limited, and may be, for example, 10 in conductivity⁵-10⁸S/m (25 ℃ C.) of metal. In one embodiment of the present invention, an iron rod is embedded in a quartz tube to be used as a central high voltage electrode.

The rod-like high voltage electrode is not particularly limited, and may be, for example, various high voltage electrodes conventionally used in the art. Fig. 3 is a schematic diagram of a plasma discharge device according to an embodiment of the invention. As shown in fig. 3, the plasma discharge apparatus according to the present invention includes a metal rod 7 as a central high voltage electrode. In one embodiment of the present invention, the center high voltage electrode 1 has a conductivity of 9.9 × 10⁶S/m of iron metal.

The ground electrode is not particularly limited, and may be, for example, a metal mesh or a metal sheet. The mesh number of the mesh ground electrode is 5 to 500 mesh, preferably 10 to 100 mesh.

The working gas in the plasma discharge device of the present invention is not limited, and may be fixed air, nitrogen, helium, argon, or the like commonly used in the art, and one or more kinds may be selected by those skilled in the art according to actual needs.

In a second aspect, the present invention provides a method of electric field enhancement, wherein the method employs the above plasma discharge apparatus. Specifically, the device shown in fig. 2 is adopted, wherein the plasma discharge device is a plasma reaction tube 4, a central high voltage electrode 1 and a metal coil 2 which are coaxially arranged, and a grounding electrode 3 which is tightly attached to the outer wall of the plasma reaction tube 4; the metal coil 2 is arranged in a discharge gap between the central high-voltage electrode 1 and the grounding electrode 3.

According to the electric field enhanced plasma discharge device provided by the invention, the metal coil is added in the discharge gap for applying the driving voltage between the high-voltage electrode and the grounding voltage electrode, and the electric fields with different strengths can be obtained by changing the wire diameter, the outer diameter and the screw pitch of the metal coil. The principle is that a change in distance at the same voltage causes a change in the electric field. In one embodiment of the invention, the outer diameter of the central high voltage electrode is 10mm, the inner diameter of the plasma reaction tube is 11.6mm, the discharge gap is 0.8mm, the outer diameter of the metal coil is 11.2mm, the wire diameter of the metal coil is 0.4mm, the two are coaxially arranged, and in the same longitudinal interface, the distance between the metal coil and the inner surface of the high voltage electrode and the inner surface of the plasma reaction tube is 0.2 mm. In another embodiment of the present invention, the same plasma reactor as described above is used except that the metal coil has an outer diameter of 11.4mm, and the metal coil is coaxially disposed with the high voltage electrode and the inner surface of the plasma reactor tube at a distance of 0.1mm and 0.3mm, respectively, in the same longitudinal interface.

In another embodiment of the present invention, the same plasma reactor as described above is used, except that the metal coils have an odd coil outer diameter of 11.2mm and an even coil outer diameter of 11.4mm, and the combination of the outer diameters of the coils may be arranged as desired.

The present invention will be described in detail below by way of examples. In the following examples, each material used was commercially available unless otherwise specified, and the method used was a conventional method in the art unless otherwise specified.

Example 1

By adopting the plasma discharge device shown in fig. 2, the central high voltage electrode 1 (specifically, a metal rod) is positioned in the plasma reaction tube 4 (specifically, a quartz tube) and is coaxially arranged with the plasma reaction tube 4, the grounding electrode (specifically, a metal sheet) 3 is tightly attached to the outer wall of the plasma reaction tube 4, the metal coil 2 is arranged around the central high voltage electrode 1 and is not contacted with the central high voltage electrode 1, the plasma reaction tube 4 is provided with a gas inlet 8 and a gas outlet 9, wherein the discharge gap is 0.8mm, the wire diameter of the metal coil 2 is 0.4mm, the metal coil is positioned in the middle of the discharge gap, the distance from the top to the bottom is 0.2mm, and the thread pitch is 2 mm.

The electric field intensity of the front viewing angle section of example 1 was simulated using the multifunctional physical field simulation software COMSOLMUTIPhysics, with an applied voltage of 3000sin (100 π t) V. As shown in FIG. 5, when the discharge length is 8mm under the action of the sinusoidal alternating electric field, it can be found that the electrostatic field in the discharge gap without the metal coil is relatively uniform, 1.15 × 10⁵About V/m, the electrostatic field distortion is serious after the metal coil with the wire diameter of 0.4mm is added, and the local part can reach 2.84 multiplied by 10⁵V/m。

Example 2

The same plasma discharge apparatus was used as in example 1, except that the wire diameter of the metal coil 2 was reduced to 0.05 mm.

The electric field intensity of the front viewing angle section of example 2 was simulated using the multifunctional physical field simulation software COMSOLMUTIPhysics, with an applied voltage of 3000sin (100 π t) V. As shown in FIG. 6, when the discharge length is 8mm under the action of the sinusoidal alternating electric field, it can be found that the electrostatic field in the discharge gap without the metal coil is relatively uniform, 1.15 × 10⁵About V/m, the electrostatic field is slightly changed after a metal coil with the wire diameter of 0.05mm is added, and the maximum electrostatic field can reach 1.17 multiplied by 10⁵V/m。

Example 3

The same plasma discharge apparatus was used as in example 1, except that the wire diameter of the metal coil 2 was increased to 0.6 mm.

The electric field strength of the front viewing angle section of example 3 was simulated using the multifunctional physical field simulation software COMSOLMUTIPhysics, with an applied voltage of 3000sin (100 π t) V. As shown in FIG. 7, when the discharge length is 8mm under the action of the sinusoidal alternating electric field, it can be found that the electrostatic field in the discharge gap without the metal coil is relatively uniform, 1.15 × 10⁵About V/m, the electrostatic field distortion is serious after the metal coil with the wire diameter of 0.6mm is added, and the local part can reach 4.62 multiplied by 10⁵V/m。

Example 4

The same plasma discharge apparatus was used as in example 1, except that the inner diameter of the metal coil was increased, and that the metal coil 2 having a wire diameter of 0.4mm was located at the discharge gap 5/8, 0.1mm from the upper surface and 0.3mm from the lower surface.

The field strength of the normal viewing angle section of example 4 was simulated using the multifunctional physical field simulation software COMSOLMUTIPhysics, with an applied voltage of 3000sin (100 π t) V. As shown in FIG. 8, the length of the discharge was taken to be 8mm under the action of the sinusoidal alternating electric field, except that the electric field was 1.15X 10 in the area where no metal conductor was involved⁵V/m, it can be found that the electrostatic field of the region of the metal coil added locally appears at two positions which can reach 2.56 multiplied by 10⁵V/m、3.20×10⁵V/m strength electric field.

Example 5

The same plasma discharge apparatus was used as in example 4, except that the pitch of the metal coil 2 was reduced to 0.66 mm.

The electric field strength of the front viewing angle section of example 5 was simulated using the multifunctional physical field simulation software COMSOLMUTIPhysics, with an applied voltage of 3000sin (100 π t) V. As shown in FIG. 9, when the discharge length is 8mm under the action of the sinusoidal alternating electric field, it can be found that the electrostatic field after the metal coil is added can reach 2.56 × 10 at four places⁵V/m、3.20×10⁵V/m strength electric field.

Example 6

The same plasma discharge apparatus was used as in example 5, except that the odd-numbered coil of the metal coil 2 was located at the discharge gap 1/2, the even-numbered coil was located at the discharge gap 5/8, and the inside diameters of the odd-even-numbered coils were different.

The electric field strength of the front viewing angle section of example 6 was simulated using the multifunctional physical field simulation software COMSOLMUTIPhysics, with an applied voltage of 3000sin (100 π t) V. As shown in FIG. 10, under the action of the sinusoidal alternating electric field, the discharge length of 8mm is taken, and it can be found that the local electrostatic field after the metal coil is added can be up to 2.84 × 10⁵V/m、2.56×10⁵V/m、3.20×10⁵V/m three strength electric fields.

According to the method provided by the invention, the distortion degree of the electric field is different by adopting different diameters and screw pitches of the metal coil, so that the control on the increase degree of the electric field is realized.

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solutions of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications all belong to the protection scope of the embodiments of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, the embodiments of the present invention do not describe every possible combination.

In addition, any combination of various different implementation manners of the embodiments of the present invention is also possible, and the embodiments of the present invention should be considered as disclosed in the embodiments of the present invention as long as the combination does not depart from the spirit of the embodiments of the present invention.