Plasma generating device

Abstract

The application discloses a kind of plasma generating device, belong to plasma generating device technical field;Including discharge component and shell component;The discharge component includes trigger electrode, main electrode, insulator and pipe body, the trigger electrode and the main electrode are embedded in the pipe body.The one end of the trigger electrode is equipped with the main electrode.The insulator is between the trigger electrode and the main electrode, the insulator is equipped with first channel, the inner cavity of the pipe body forms second channel, and the main electrode is equipped with through-hole.The shell component is equipped with the jet port being communicated with the second channel.The application embeds trigger electrode and main electrode in pipe body, realizes the close cooperation of trigger electrode and main electrode, improves the airtightness, prevents pipe body from leaking.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plasma generating devices, and particularly relates to a plasma generating device. BACKGROUND

[0002] Capillary discharge generally forms a plasma jet by ablation of the tube wall of a low-melting polymer material, and has the characteristics of high density (10 23 -10 27 m -3 ), low electron temperature (1-5 eV) and high speed (>10 km / s), and is widely used in material surface treatment, electrothermal / electrothermal chemical emission and other fields. Generally, a capillary plasma generator uses a metal wire as an ignition medium, and an initial plasma is formed by electric explosion of the metal wire connected between an anode and a cathode through a high-voltage pulse, and further, a hot plasma jet is formed by continuous ablation of the capillary tube wall during the discharge process. However, the capillary structure using a metal wire to generate an initial plasma is difficult to realize discharge and high heat load behavior. The two-stage capillary plasma generator uses air instead of a metal wire as an ignition medium to solve the above problems, but the two-stage capillary has a structure matching problem, and the internal gas pressure of the capillary discharge is as high as tens of megapascals, which will cause air leakage problems, thereby affecting the capillary discharge process, and the capillary structure is severely ablated and damaged at the defect of the capillary airtightness, and cannot meet the stable and reliable experimental requirements. SUMMARY

[0003] The purpose of the present application is to provide a plasma generating device to overcome the air leakage problem caused by the structure matching of the existing two-stage capillary, and the present application can effectively prevent air leakage and further increase the airtightness.

[0004] The plasma generating device of the present application comprises a discharge assembly and a shell assembly sleeved outside the discharge assembly.

[0005] The discharge assembly comprises a trigger electrode, a main electrode, an insulator and a tube body, and the trigger electrode and the main electrode are embedded in the tube body.

[0006] The trigger electrode comprises a first end and a second end away from the first end, the first end is arranged in the shell assembly, the second end is arranged outside the shell assembly, the second end is connected with a high-voltage pulse source, the main electrode is sleeved outside the first end, and the main electrode is connected with a nanosecond negative pulse source.

[0007] The insulator is arranged between the trigger electrode and the main electrode, the insulator is provided with a first channel communicating the trigger electrode and the main electrode, the inner cavity of the tube body forms a second channel, and the main electrode is provided with a through hole communicating the first channel and the second channel.

[0008] The shell assembly is provided with a jet opening communicated with the second channel, the voltage between the main electrode and the trigger electrode breaks through the first channel to generate a first arc, the first arc ablates the insulator to generate an ignition plasma, the ignition plasma enters the second channel through the through hole, the ignition plasma discharge breaks through the second channel to generate a second arc, the second arc ablates the channel wall of the second channel to generate plasma, and the plasma is jetted out of the jet opening.

[0009] Compared with the prior art, the present application has the following beneficial technical effects:

[0010] The plasma generating device of the present application embeds the trigger electrode and the main electrode in the pipe body, realizes the close cooperation of the trigger electrode and the main electrode, improves the sealing performance, and prevents the pipe body from leaking. The first channel, the through hole, the second channel and the jet opening are arranged to make the main electrode and the trigger electrode work to break through the first channel to generate a first arc, the first arc ablates the insulator to generate an ignition plasma, the ignition plasma enters the second channel through the through hole, the ignition plasma discharge breaks through the second channel to generate a second arc, the second arc ablates the channel wall of the second channel, i.e. the inner wall of the pipe body, to generate plasma, and the plasma is jetted out of the jet opening. The plasma is jetted out in the direction from the first channel to the jet opening, which reduces the pressure in the pipe body and prevents the leakage phenomenon from occurring. The discharge assembly is arranged in the shell assembly to further improve the sealing performance. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a structure schematic view of the plasma generating device in the embodiment of the present application.

[0012] Figure 2 It is a structure schematic view of the plasma generating device in the embodiment of the present application. Figure 1 It is a partial enlarged view of the plasma generating device.

[0013] In the figure, 11 is a pipe body, 111 is a second channel, 12 is a main electrode, 121 is a through hole, 13 is a first insulating sleeve, 131 is a first channel, 14 is a bottom plate, 15 is a second insulating sleeve, 16 is a trigger electrode, 21 is a first end cover, 211 is a jet opening, 22 is a ground electrode, 23 is an insulating shell, and 24 is a second end cover. DETAILED DESCRIPTION

[0014] In order to make the person skilled in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0015] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0016] The two-stage capillary is composed of a main electrode and a trigger electrode to form a discharge circuit; through the time sequence control of the high-voltage pulse source connected with the main electrode and the negative pulse source connected with the trigger electrode, the discharge is first carried out in the trigger gap to generate a weak pilot plasma and inject it into the main gap. Further, the weak plasma causes the discharge of the main gap, and after the discharge, a high-heat-load plasma jet can be formed. The two-stage capillary structure does not need to be filled with metal wires, and can realize the discharge and high-heat-load behavior.

[0017] Figure 1 And Figure 2 The present application protects a plasma generating device, which comprises a discharge assembly and a shell assembly sleeved outside the discharge assembly.

[0018] The discharge assembly comprises a trigger electrode 16, a main electrode 12, an insulator and a pipe body 11, the trigger electrode 16 and the main electrode 12 are embedded in the pipe body 11, and the trigger electrode 16 and the main electrode 12 are coaxially arranged.

[0019] The main electrode 12 is a hollow column, embedding the hollow column-shaped main electrode 12 in the pipe body 11 can increase the axial length and the radial length of the main electrode 12, and further increase the contact area between the main electrode 12 and the pipe body 11, and the involved connecting ports are in close-fitting matching, so that the main electrode 12 and the pipe body 11 are in close contact and the airtightness is enhanced. The insulator and the pipe body 11 are both selected as polymer materials with low melting and boiling points, and the pipe body 11 is preferably a capillary.

[0020] The trigger electrode 16 comprises a first end and a second end away from the first end, the first end is arranged in the shell assembly, the first end of the trigger electrode 16 is sheathed with the main electrode 12, the second end of the trigger electrode 16 is arranged outside the shell assembly, and the second end of the trigger electrode 16 is used for being connected with the high-voltage pulse source, and the main electrode 12 is used for being connected with the nanosecond negative pulse source.

[0021] An insulator is arranged between the trigger electrode 16 and the main electrode 12, the insulator is provided with a first channel 131 communicating the trigger electrode 16 and the main electrode 12, the inner cavity of the tube body 11 forms a second channel 111, and the main electrode 12 is provided with a through hole 121 communicating the first channel 131 and the second channel 111.

[0022] The shell assembly is provided with a jet port 211 communicating with the second channel 111. The voltage between the main electrode 12 and the trigger electrode 16 breaks down the air in the first channel 131 to generate a first arc, the first arc ablates the insulator to generate an ignition plasma, the ignition plasma passes through the through hole 121 into the second channel 111, the ignition plasma discharges to break down the air in the second channel 111 to generate a second arc, the second arc ablates the channel wall of the second channel 111 to generate plasma, and the plasma is sprayed out of the jet port 211. In the present application, the breakdown of the air refers to the generation of an arc, and the arc is used for ablating the insulator.

[0023] By embedding the trigger electrode 16 and the main electrode 12 in the tube body 11, the trigger electrode 16 and the main electrode 12 are tightly matched, the ignition plasma and the plasma generated by the two are both arranged in the tube body 11, the whole system is sealed in the tube body 11, and good airtightness is achieved. The plasma is sprayed in a fixed direction from the first channel 131 to the jet port 211, and the plasma is generated and sprayed in a fixed direction, which reduces the pressure of the plasma on the tube body 11 in other directions and prevents air leakage. By arranging the shell assembly, the discharge assembly is arranged in the shell assembly, the shell assembly can be sealed, and the airtightness is further improved.

[0024] Reference Figure 1 and Figure 2 In one specific embodiment, the main electrode 12 is a tubular structure with one end sealed, that is, the axial section of the main electrode 12 is in the shape of U, and the sealed end of the main electrode 12 is provided with the through hole 121. The U-shaped main electrode 12 can semi-wrap the first end of the trigger electrode 16, and the two are filled with the insulator, thereby improving the airtightness of the cooperation between the trigger electrode 16 and the main electrode 12.

[0025] Reference Figure 1 and Figure 2In another embodiment, the trigger electrode 16, the main electrode 12, the first channel 131, the second channel 111 and the through hole 121 are coaxially arranged. The coaxial arrangement is to ensure that the plasma can be generated and ejected without any obstruction, so that the plasma can be generated and ejected smoothly, the emission efficiency of the plasma can be improved, and the pressure generated by the accumulation of the plasma on the channel can be prevented to cause the pipe body 11 to leak.

[0026] The diameter of the first channel 131 is 0.5mm-1.5mm, preferably 0.5mm, 1mm and 1.5mm. The length is 1mm-2mm. The first channel 131 in this diameter and length range can be easily broken down by the voltage between the trigger electrode 16 and the main electrode 12 to generate the ignition plasma.

[0027] The diameter of the through hole 121 is 0.5mm-1.5mm, preferably 0.5mm, 1mm and 1.5mm. Among them, the diameter of the through hole 121 is preferably the same as the diameter of the first channel 131, which is conducive to the passage of the ignition plasma.

[0028] The diameter of the second channel 111 is 3mm-5mm, preferably 3mm, 4mm and 5mm; the length is 75mm-90mm, preferably 75mm, 80mm, 85mm and 90mm. The second channel 111 in this range makes it easy for the plasma to be excited by the ignition plasma to form a plasma, and the plasma has a pressure difference in the axial direction, so that the plasma can move away from the through hole 121.

[0029] In another embodiment, the main electrode 12 is made of tungsten-copper alloy, the main electrode 12 is in a hollow columnar shape, the outer end of the main electrode 12 is connected to the bottom plate 14 by threads, the rear end of the main electrode 12 is provided with a through hole 121, the diameter of the through hole 121 is 1mm, and the long columnar structure of the main electrode 12 extends into the pipe body 11 to realize the close cooperation between the main electrode 12 and the pipe body 11, and to ensure the tightness of the contact surface.

[0030] In another embodiment, the insulator and the pipe body 11 are made of one or more of polyethylene, polytetrafluoroethylene and polycarbonate. These materials can replace the metal wire as the ignition medium, and when the voltage breaks down the first channel 131, the first arc can ablate the insulator to generate the ignition plasma, and the ignition plasma can further excite these materials to generate the plasma.

[0031] Reference Figure 1 and Figure 2In another embodiment, the insulator comprises a first insulating sleeve 13 and a second insulating sleeve 15. The first insulating sleeve 13 is arranged between the first end and the main electrode 12, the first insulating sleeve 13 is adapted to the shape of the main electrode 12, a first channel 131 is formed in the first insulating sleeve 13, and the second insulating sleeve 15 is arranged between the first end and the first insulating sleeve 13. The first insulating sleeve 13 is ablated as the insulator to generate the ignition plasma under the first arc. The second insulating sleeve 15 functions as an insulator between the first end and the main electrode 12, and is arranged on the side of the first end, and also functions to close the first channel 131.

[0032] Referring to Figure 1 and Figure 2 In another embodiment, the discharge assembly further comprises a bottom plate 14 connected to one end of the tube body 11 close to the first end, wherein the main electrode 12 is connected to the bottom plate 14, and the bottom plate 14 is connected to the nanosecond negative pulse source. The main purpose of arranging the bottom plate 14 is to improve the sealing of the tube body 11. The main electrode 12 does not protrude out of the shell assembly, so when the main electrode 12 is connected to the nanosecond negative pulse source, it is easy to damage the tube body, which may cause the tube body to leak. Arranging the bottom plate 14 at one end of the tube body 11 can ensure the sealing of the tube body 11 when the main electrode 12 is connected to the nanosecond negative pulse source through the bottom plate 14. The main electrode 12 and the bottom plate 14 can be threadedly connected, and the tube body 11 and the bottom plate 14 can also be threadedly connected.

[0033] Referring to Figure 1 and Figure 2 In another embodiment, the shell assembly further comprises a first end cover 21, a ground electrode 22, an insulating shell 23, and a second end cover 24; the first end cover 21, the ground electrode 22, the insulating shell 23, the bottom plate 14, and the second end cover 24 are sequentially connected to enclose a closed space, and the first end, the insulator, the main electrode 12, and the tube body 11 are accommodated in the closed space. The first end cover 21 and the second end cover 24 are arranged at both ends of the tube body 11, and the bottom plate 14 is further arranged between the second end cover 24 and the tube body 11. The ground electrode 22 and the insulating shell 23 are arranged on the outside of the tube body, and the insulating shell 23 is arranged between the ground electrode 22 and the bottom plate 14 to function as an insulator. The first end cover 21 is provided with a spray port 211.

[0034] Referring to Figure 1 and Figure 2 Sealing rings are arranged between the first end cover 21 and the tube body 11, between the first end cover 21 and the ground electrode 22, between the ground electrode 22 and the insulating shell 23, between the bottom plate 14 and the second end cover 24, and between the second end cover 24 and the second insulating sleeve 15. The sealing rings are used to improve the sealing of the shell assembly and provide a closed environment for the discharge assembly.

[0035] In another specific embodiment, the sealing ring is one or more than two of a fluororubber sealing ring, a butyronitrile sealing ring. The sealing ring of this material has strong thermal stability and pressure resistance, and is suitable for sealing the shell assembly. In this application, the fluororubber sealing ring is used to seal multiple parts of the device, which can greatly improve the overall sealing performance and prevent external gas or plasma leakage. Further, the use of multiple insulation structures greatly reduces the possibility of plasma damaging the insulating shell 23 and causing short circuits, while significantly improving the insulation performance of the device to ensure the reliability and stability of the discharge.

[0036] In another specific embodiment, a flange is provided outside the ground electrode 22. The material of the main electrode 12 can be tungsten-copper alloy material, and the first end cover 21 and the second end cover 24 can be 304 stainless steel material. The ground electrode 22, the insulating shell 23 and the bottom plate 14 are connected by fastening bolts, and the fastening bolts are made of nylon reinforced with glass fiber insulation plastic material.

[0037] Reference Figure 1 and Figure 2 In another specific embodiment, the second insulating sleeve 15 is nested on the first end, the first insulating sleeve 13 is nested on the second insulating sleeve 15, the main electrode 12 and the trigger electrode 16 are discharged first to make the air in the first channel 131 be broken down and generate a first electric arc, under the action of ohmic heating and radiation heat, the first electric arc ablates the polyethylene wall material of the first channel 131 to generate an initial plasma, i.e. an ignition plasma. The ignition plasma is injected into the second channel 111 through the through hole 121, at this time the nanosecond pulse process on the trigger electrode 16 ends, the ignition plasma existing in the second channel 111 triggers the discharge of the main electrode 12 and the ground electrode 22 to break down the second channel 111 to form a second electric arc, and the second electric arc ablates the polyethylene wall material of the second channel 111 to generate plasma. The plasma continues to ablate the polyethylene wall material of the second channel 111, causing it to decompose and ionize, supplementing the overall plasma mass. Under the action of a huge pressure gradient, the plasma is ejected from the jet opening of the slope opening, forming a hot plasma jet.

[0038] The above only discloses the preferred embodiments of the present application, and of course cannot limit the scope of the rights of the present application, so the equivalent changes made according to the claims of the present application still fall within the scope of the present application.

Claims

1. A plasma generating device, characterized by comprising: The discharge assembly and the shell assembly arranged outside the discharge assembly; The discharge assembly comprises a trigger electrode (16), a main electrode (12), an insulator and a tube body (11), the trigger electrode (16) and the main electrode (12) are embedded in the tube body (11); The trigger electrode (16) comprises a first end and a second end away from the first end, the first end is arranged in the shell assembly, the second end is arranged outside the shell assembly, the second end is connected with a high-voltage pulse source, the first end is sleeved with the main electrode (12), the main electrode (12) is connected with a nanosecond negative pulse source; The insulator is arranged between the trigger electrode (16) and the main electrode (12), the insulator is provided with a first channel (131) communicating the trigger electrode (16) and the main electrode (12), the inner cavity of the tube body (11) forms a second channel (111), and the main electrode (12) is provided with a through hole (121) communicating the first channel (131) and the second channel; The shell assembly is provided with a jet port (211) communicating with the second channel (111), the voltage between the main electrode (12) and the trigger electrode (16) breaks down the first channel (131) to generate a first arc, the first arc ablates the insulator to generate an ignition plasma, the ignition plasma enters the second channel (111) through the through hole, the ignition plasma discharge breaks down the second channel (111) to generate a second arc, and the second arc ablates the channel wall of the second channel (111) to generate plasma, and the plasma is jetted out of the jet port.

2. The plasma generating device of claim 1, wherein The main electrode (12) is a tubular structure with one end sealed, and the sealed end of the main electrode is provided with the through hole (121).

3. The plasma generating device of claim 2, wherein The trigger electrode, the main electrode (12), the first channel (131), the second channel (111) and the through hole (121) are coaxially arranged.

4. The plasma generating device of claim 1, wherein The diameter of the first channel (131) is 0.5mm-1.5mm, and the length is 1mm-2mm; The diameter of the second channel (111) is 3mm-5mm, and the length is 75mm-90mm.

5. The plasma generating device of claim 1, wherein, The material of the insulator and the tube body (11) is selected from one or more of polyethylene, polytetrafluoroethylene and polycarbonate.

6. The plasma generating device according to any one of claims 1 to 5, wherein The insulator comprises a first insulating sleeve (13) and a second insulating sleeve (15), the first insulating sleeve (13) is arranged between the first end and the main electrode (12), the shape of the first insulating sleeve (13) is matched with the main electrode (12), and the first channel (131) is formed in the first insulating sleeve (13); the second insulating sleeve (15) is arranged between the first end and the first insulating sleeve (13).

7. The plasma generating device of claim 6, wherein The discharge assembly further comprises a bottom plate (14) connected to one end of the tube body (11) near the first end, wherein the main electrode (12) is connected to the bottom plate (14), and the bottom plate (14) is connected to the nanosecond negative pulse source.

8. The plasma generating device of claim 7, wherein, The shell assembly further comprises a first end cover (21), a ground electrode (22), an insulating shell (23) and a second end cover (24); the first end cover (21), the ground electrode (22), the insulating shell (23), the bottom plate (14) and the second end cover (24) are sequentially connected to enclose a sealed space, and the first end, the insulating shell (23), the main electrode (12) and the tube body (11) are accommodated in the sealed space. The first end cover (21) is provided with the spray port (211).

9. The plasma generating device of claim 8, wherein, Sealing rings are arranged between the first end cover (21) and the tube body (11), between the first end cover (21) and the ground electrode (22), between the ground electrode (22) and the insulating shell (23), between the bottom plate (14) and the second end cover (24), and between the second end cover (24) and the second insulating sleeve (15).

10. The plasma generating device of claim 9, wherein, The sealing ring is one or more than two of a fluororubber sealing ring and a butyronitrile sealing ring.

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