阅读说明：本技术 一种产生重频高热负荷等离子体射流的毛细管系统 (Capillary system for generating repeated-frequency high-heat-load plasma jet ) 是由 陈立 李兴文 蒋仕 杨伟鸿 谷坤泉 于 2020-05-15 设计创作，主要内容包括：本发明公开了一种产生重频高热负荷等离子体射流的毛细管系统,毛细管的一端呈开口设置,开口处的一侧管壁上设置有地电极,毛细管的另一端设置有绝缘,高压电极的一端设置在毛细管的管壁处,另一端伸出至绝缘的外部连接高压脉冲电源,毛细管中间管段的管壁上设置有触发电极,触发电极作为放电电弧的起燃引弧阶段通道,并连接负触发脉冲,在毛细管的触发极和高压极之间施加重频触发脉冲,通过控制触发脉冲产生和开关的导通时序,实现毛细管重频放电产生重复频率的热等离子流。本发明通过优化设计电路结构,减小装置体积、减少元件数量,进而降低装置成本的作用,提供了高效、稳定、安全的实现方案。(The invention discloses a capillary system for generating plasma jet with repeated frequency and high thermal load, wherein one end of a capillary is arranged in an opening, a ground electrode is arranged on the tube wall on one side of the opening, the other end of the capillary is provided with an insulator, one end of a high-voltage electrode is arranged on the tube wall of the capillary, the other end of the high-voltage electrode extends out of the insulated outside and is connected with a high-voltage pulse power supply, a trigger electrode is arranged on the tube wall of a middle tube section of the capillary, the trigger electrode is used as a channel of a firing and arc-striking stage of a discharge arc and is connected with a negative trigger pulse, the repeated frequency trigger pulse is applied between the trigger electrode and the high-voltage electrode of the capillary, and the generation of the repeated frequency thermal plasma. The invention reduces the volume of the device and the number of elements by optimally designing the circuit structure, thereby reducing the cost of the device and providing a high-efficiency, stable and safe implementation scheme.)

1. A capillary system for generating plasma jet with heavy frequency and high thermal load is characterized by comprising a capillary tube (2), wherein one end of the capillary tube (2) is arranged in an opening manner, a ground electrode (3) is arranged on the tube wall on one side of the opening, an insulator (11) is arranged at the other end of the capillary tube (2), one end of a high-voltage electrode (1) is arranged on the tube wall of the capillary tube (2), the other end of the high-voltage electrode extends out of the insulator (11) to be connected with a high-voltage pulse power supply (4), a trigger electrode (2) is arranged on the tube wall of a middle tube section of the capillary tube (12), the trigger electrode (2) is used as a channel in the ignition and arc striking stage of a, the repetition frequency trigger pulse is applied between the trigger electrode and the high-voltage electrode of the capillary (2), and the thermal plasma flow (13) with repetition frequency generated by the capillary repetition frequency discharge is realized by controlling the generation of the trigger pulse and the conduction time sequence of the switch.

2. The capillary system for generating plasma jet with heavy frequency and high heat load according to claim 1, wherein one end of the high voltage electrode (1) passes through the insulation (11) and is attached to the wall of the capillary (12), the other end is connected with the high voltage pulse source (4) through the thyristor (6) and the wave-modulating inductor (5) in sequence, and the high voltage pulse triggers the high voltage electrode (1) to serve as an anode.

3. Capillary system for generating a plasma jet with high heat load at high frequency according to claim 1, characterized in that the duration of the high level of the thyristor (6) is 25-70 μ s.

4. The capillary system for generating plasma jet with heavy frequency and high heat load according to claim 1 is characterized in that the trigger electrode (2) is arranged close to the wall of the capillary (12), and the length of the tube from the trigger electrode (2) to the high voltage electrode (1) is 1/7-1/5 of the length of the capillary (12).

5. The capillary system for generating plasma jet with heavy frequency and high thermal load according to claim 1 is characterized in that the ground electrode (3) is hollow, the electrode hole at one end is closely attached to the tube wall of the capillary (12), and the other end is grounded and connected as the cathode.

6. The capillary system for generating a plasma jet with a heavy frequency and a high thermal load according to claim 1, characterized in that the negative trigger pulse (7) is divided into two paths after passing through the isolation capacitor (8), one path is connected with the extending end of the trigger electrode (2), and the other path is connected to ground after passing through the diode (9) and the ground resistor (10) in sequence.

7. The capillary system for generating plasma jet with heavy frequency and high heat load according to claim 6, characterized in that the negative trigger pulse (7) comprises a nano-sized capacitor (17), one end of the nano-sized capacitor (17) is connected with the isolation capacitor (8) after passing through the first switching device (15) and the first wave-modulating inductor (14) in sequence, the other end is divided into two paths, one path is grounded with the high-voltage pulse source (4), and the other path is connected with the isolation capacitor (8) after passing through the first freewheeling diode (16) and the first wave-modulating inductor (14) in sequence.

8. The capillary system for generating a plasma jet with a high heat load and a high frequency according to claim 6, characterized in that the negative trigger pulse (7) comprises a pulse transformer (18), one end of the output end of the pulse transformer (18) is divided into two paths, one path is connected with one end of the energy storage capacitor (20), the other path is connected with the common end of the second switching device (19), the normally open end of the second switching device (19) is divided into two paths, one path is connected with the cathode of the second freewheeling diode (21), and the other path is connected with the isolation capacitor (8) through the second wave modulating inductor (22); the other end of the output end of the pulse transformer (18) is divided into three paths, and the three paths are respectively connected with the other end of the energy storage capacitor (20), the anode of the second fly-wheel diode (21) and the high-voltage pulse source (4) in a common ground mode.

9. Capillary system for generating a plasma jet with heavy frequency and high thermal load according to claim 7 or 8, characterized in that the duration of the high level of the first switching device (15) or the second switching device (19) is 300-700 ns.

10. Capillary system for generating a heavy frequency high thermal load plasma jet according to claim 1, characterized in that the repetition frequency of the thermal plasma flow (13) is equal to or less than 50 Hz.

Technical Field

The invention belongs to the technical field of plasma generating devices, and particularly relates to a capillary system for generating a repeated-frequency high-heat-load plasma jet.

Background

A capillary pulsed plasma generator is a common structure used to generate thermal plasma. The high-voltage pulse is applied to two electrodes connected to a capillary tube to cause a discharge phenomenon, so that plasma jet with high temperature, high density and high speed is generated. The capillary tube wall material is usually hydrocarbon polymer such as polyethylene, the tube has a length of several centimeters to ten centimeters, an inner diameter of two millimeters to six millimeters, and a diameter-length ratio of less than 0.1. Two ends of the capillary tube are respectively connected with two poles of a high-voltage power supply, one end of the capillary tube is a closed electrode, and the other end of the capillary tube is a hollow nozzle electrode. Under the high-voltage pulse discharge, the tube wall of the capillary can be rapidly heated and ablated by the large pulse current with millimeter-level pulse width to generate thermal plasma, and the thermal plasma is sprayed to the hollow nozzle end from the closed end under the action of the pressure in the capillary, so that high-temperature, high-density and high-speed thermal plasma flow is formed.

The thermal plasma generated by the capillary pulse plasma generator can be used in the fields of material spraying, waste treatment, soft X-ray, electric propulsion, gun medicament combustion control and the like. At present, a typical capillary pulse plasma generator usually connects a wire between a closed electrode and a nozzle electrode, the wire is vaporized to form initial plasma under the action of high-voltage pulse, and finally hot plasma flow is formed by ablating the tube wall in the discharge process. However, when the capillary is required to realize the repetition frequency discharge to generate the repetition frequency high heat load plasma flow, the typical capillary plasma generator cannot meet the corresponding requirements.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a capillary system for generating a repetition frequency high thermal load plasma jet, which solves the problem that a capillary plasma generator cannot realize a repetition frequency high thermal load plasma jet, and provides a new circuit structure to make the system stable, safe and efficient.

The invention adopts the following technical scheme:

the utility model provides a produce capillary system of high thermal load plasma efflux of repetition frequency, including the capillary, the one end of capillary is the opening setting, be provided with the ground electrode on the pipe wall of one side of opening part, the other end of capillary is provided with the insulation, the one end setting of high voltage electrode is in the pipe wall department of capillary, the other end stretches out to insulating external connection high voltage pulse power, be provided with trigger electrode on the pipe wall of section in the middle of the capillary, trigger electrode is as the ignition striking arc stage passageway of discharge arc, and connect the negative trigger pulse, exert repetition frequency trigger pulse between the trigger electrode of capillary and high voltage electrode, through the conduction time sequence of control trigger pulse production and switch, realize the thermal plasma stream that capillary repetition frequency discharge produced repetition frequency.

Specifically, one end of the high-voltage electrode penetrates through the insulation to be tightly attached to the tube wall of the capillary tube, the other end of the high-voltage electrode is connected with a high-voltage pulse source through the thyristor and the wave-regulating inductor in sequence, and the high-voltage pulse triggers the high-voltage electrode to serve as an anode.

Specifically, the duration time of the high level of the thyristor is 25-70 mus.

Specifically, the trigger electrode is arranged close to the tube wall of the capillary tube, and the length from the trigger electrode to the high-voltage electrode is 1/7-1/5 of the length of the capillary tube.

Specifically, the ground electrode is of a hollow structure, an electrode hole at one end is arranged in a manner of being attached to the pipe wall of the capillary, and the other end is connected to the ground to serve as a cathode.

Specifically, the negative trigger pulse is divided into two paths after passing through the isolation capacitor, one path is connected with the extending end of the trigger electrode, and the other path is connected with the ground after sequentially passing through the diode and the ground resistor.

Furthermore, the negative trigger pulse comprises a nano-scale capacitor, one end of the nano-scale capacitor is connected with the isolation capacitor after sequentially passing through the first switching device and the first wave regulating inductor, the other end of the nano-scale capacitor is divided into two paths, one path is grounded with the high-voltage pulse source, and the other path is connected with the isolation capacitor after sequentially passing through the first freewheeling diode and the first wave regulating inductor.

Furthermore, the negative trigger pulse comprises a pulse transformer, one end of the output end of the pulse transformer is divided into two paths, one path is connected with one end of the energy storage capacitor, the other path is connected with the common end of the second switching device, the normally open end of the second switching device is divided into two paths, one path is connected with the negative electrode of the second fly-wheel diode, and the other path is connected with the isolation capacitor through the second wave-modulating inductor; the other end of the output end of the pulse transformer is divided into three paths, and the three paths are respectively connected with the other end of the energy storage capacitor, the anode of the second fly-wheel diode and the high-voltage pulse source in common.

Furthermore, the high level duration time of the first switch device or the second switch device is 300-700 ns.

Specifically, the repetition frequency of the thermal plasma flow is 50Hz or less.

Compared with the prior art, the invention has at least the following beneficial effects:

the invention relates to a capillary system for generating plasma jet with heavy frequency and high thermal load, which adopts a high-voltage pulse source and a negative trigger pulse triggering mode to enhance the controllability of capillary discharge, can control the ignition and arc ignition process of capillary discharge by controlling the pulse width and the amplitude of two power sources and controlling the time sequence of a switch, so that the capillary discharge is safer, more stable, efficient and reliable; the pulse width and amplitude control of the power supply can control the speed of the ignition and arc ignition process, so that the subsequent main discharge process is influenced, and the effects of adjusting the temperature, density and speed of the ejected thermal plasma flow are achieved.

Furthermore, the length of the tube from the trigger electrode to the high-voltage electrode accounts for 1/7-1/5 of the length of the capillary, so that the ignition process between the high-voltage electrode and the trigger electrode and the main discharge process between the high-voltage electrode and the ground electrode can be well matched.

Furthermore, by designing a structure that the hollow ground electrode is tightly attached to the pipe wall at the nozzle of the capillary, a spraying channel and a nozzle are ingeniously provided for the thermal plasma flow, and the stability of the device in the discharging process is improved.

Furthermore, by designing the resistor, the capacitor and the diode in the circuit loop, the circuit can be effectively protected, the circuit structure is simplified, the size of the device is reduced, the number of elements is reduced, and the cost of the device is reduced

Furthermore, the mode that the energy storage capacitor directly discharges to generate the negative pulse is adopted, the size of the device can be reduced, the number of elements can be reduced, meanwhile, the efficiency of the negative pulse generating circuit is improved, the operation is simple, and the requirement on the energy storage capacitor is higher.

Furthermore, the mode of generating the negative pulse through the pulse transformer structure can effectively improve the voltage, has low requirement on the energy storage capacitor and is easy to realize.

Furthermore, the realization of the plasma jet with high heat load of the repetition frequency is innovative and valuable, and provides experimental conditions for examining the damage of the plasma jet with the repetition frequency to materials, such as the plasma jet can be well applied to an electrothermal chemical gun, a Tokamak device and an electric propeller.

In summary, the capillary system for generating the plasma jet with the repetition frequency and the high heat load of the invention achieves the purpose of generating the plasma flow with the repetition frequency and the high heat load by the discharge of the capillary on the one hand, and can adjust the parameters of the plasma flow with the repetition frequency and the high heat load by the control of the switch time sequence on the other hand. Meanwhile, the invention reduces the volume of the device and the number of elements by optimally designing the circuit structure, thereby reducing the cost of the device and providing a high-efficiency, stable and safe implementation scheme.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic diagram of a design of a capillary system;

FIG. 2 is a diagram of a negative trigger pulse circuit for direct discharge of large capacitor stored energy;

FIG. 3 is a diagram of a negative trigger pulse circuit that is boosted by a transformer and discharged by a small capacitor;

FIG. 4 is a diagram of a switch timing control.

Wherein: 1. a high voltage electrode; 2. a trigger electrode; 3. a ground electrode; 4. a high voltage pulse source; 5. a wave modulation inductor; 6. a thyristor; 7. a negative trigger pulse; 8. an isolation capacitor; 9. a diode; 10. a ground resistor; 11. insulating; 12. a capillary tube; 13. a flow of hot plasma; 14. a first wave modulating inductor; 15. a first switching device; 16. a first freewheeling diode; 17. a nano-scale capacitor; 18. a pulse transformer; 19. a second switching device; 20. an energy storage capacitor; 21. a second freewheeling diode; 22. and a second wave modulating inductor.

Detailed Description

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The invention provides a capillary system for generating plasma jet with repeated frequency and high thermal load, which enables a capillary plasma generator to generate high-frequency thermal load plasma and enables the ignition and arc striking stages to be better controlled by improving the capillary structure and the pulse power supply and the circuit structure.

Referring to fig. 1, the capillary system for generating a plasma jet with a high repetition frequency and a high thermal load of the present invention comprises a capillary tube 2 and a pulse power circuit, wherein the capillary tube 12 is made of polyethylene, and three electrodes, namely a high voltage electrode 1, a trigger electrode 2 and a ground electrode 3, are arranged on the wall of the capillary tube; the pulse power supply circuit comprises a high-voltage pulse power supply 4 and a negative trigger pulse 7, wherein the high-voltage pulse power supply 4 is connected with a high-voltage electrode 1, the negative trigger pulse 7 is connected with a trigger electrode 2, a ground electrode 3 is grounded, the capillary tube adopts a two-stage structure, a repetition frequency trigger pulse is applied between the trigger electrode and the high-voltage electrode, the generation of the trigger pulse and the conduction time sequence of the thyristor are controlled, the repetition frequency discharge of the capillary tube is realized, and a high-heat-load plasma jet with the repetition frequency of 50Hz, namely a hot plasma jet 13, is. On one hand, the purpose of generating plasma flow with repeated frequency and high heat load by capillary discharge is realized, and on the other hand, the parameters of the thermal plasma flow can be adjusted through switch time sequence control.

The high-voltage electrode 1, the trigger electrode 2 and the ground electrode 3 are all made of ablation-resistant metal materials such as tungsten and tungsten-copper alloy.

One end of the high-voltage electrode 1 penetrates through an insulation 11 arranged at one end of the capillary tube 12 to be attached to the tube wall of the capillary tube 12, the other end of the high-voltage electrode is connected with a high-voltage pulse source 4 through a thyristor 6 and a wave-regulating inductor 5 in sequence, and the high-voltage pulse triggers the high-voltage electrode 1 to serve as an anode in a capillary tube discharge system.

The wave modulation inductor 5 plays a role in modulating pulse waveforms, and the time sequence of the thyristor 6 is controlled to control the action time of trigger pulses on the high-voltage electrode 1; the insulation 11 can seal the closed end of the capillary 12 to form a large gas pressure to eject the plasma stream, and insulate and protect the discharge in the capillary 12 from the outside.

The trigger electrode 2 is tightly attached to the wall of the capillary 12, one end of the trigger electrode 2 extends into the middle pipe section of the capillary 12, the length of the trigger electrode 2 to the high-voltage electrode 1 is 1/7-1/5 of the length of the capillary 12, and the trigger electrode 2 and the high-voltage electrode are used as channels of a starting and striking stage of a discharge arc.

The negative trigger pulse 7 is connected with the extending end of the trigger electrode 2 through an isolation capacitor 8, the trigger electrode 2 is used as the cathode of a capillary discharge system, and meanwhile, the trigger electrode 2 is grounded through a diode 9 and a grounding resistor 10 in sequence.

The performance of the diode 9 can pass through a large current, the grounding resistance 10 is selected to be 100 ohms, and the branch can discharge the current in the ignition and arc striking stage.

The negative trigger pulse 7 comprises a negative trigger pulse circuit for directly discharging stored energy of a large capacitor and a negative trigger pulse circuit for boosting voltage of a transformer and discharging by using a small capacitor.

Referring to fig. 2, the negative trigger pulse circuit for direct discharge of large-capacitance energy storage includes a nano-scale capacitor 17, one end of the nano-scale capacitor 17 is connected to an isolation capacitor 8 after passing through a first switching device 15 and a first wave-regulating inductor 14 in sequence, the other end is divided into two paths, one path is grounded with a high-voltage pulse source 4, and the other path is connected to the isolation capacitor 8 after passing through a first freewheeling diode 16 and the first wave-regulating inductor 14 in sequence.

Referring to fig. 3, the negative trigger pulse circuit for performing discharging by using a small capacitor through voltage boosting of a transformer includes a pulse transformer 18, one end of an output end of the pulse transformer 18 is divided into two paths, one path is connected with one end of an energy storage capacitor 20, the other path is connected with a common end of a second switching device 19, a normally open end of the second switching device 19 is divided into two paths, one path is connected with a cathode of a second freewheeling diode 21, and the other path is connected with an isolation capacitor 8 through a second wave-modulating inductor 22; the other end of the output end of the pulse transformer 18 is divided into three paths, and the three paths are respectively connected with the other end of the energy storage capacitor 20, the anode of the second fly-wheel diode 21 and the high-voltage pulse source 4 in a common ground mode.

The ground electrode 3 is a hollow structure, the electrode small hole of the ground electrode 3 is tightly attached to the tube wall of the capillary tube 12, and simultaneously, the ground electrode is directly grounded to be used as the cathode of the capillary tube discharge system, and the repeated-frequency high-heat-load plasma current 13 is ejected from the openings of the ground electrode 3 and the capillary tube 12.

Referring to fig. 4, the duration of the high level of the first switching device 15 or the second switching device 19 is 300 to 700ns, and the duration of the high level of the thyristor 6 is 25 to 70 μ s.

In the working process, the high-voltage electrode 1 and the trigger electrode 2 are ignited and arc-ignited to form stronger discharge through the switch time sequence control on the high-voltage pulse source 4 and the negative trigger pulse 7; in this stage, the high pulse current will rapidly heat and ablate the wall of the polyethylene capillary tube between the high voltage electrode and the trigger electrode, thereby generating C, H, CO and initial plasma, and rapidly generating a larger pressure to push the substances to flow towards the open end of the capillary tube.

When the initial plasma flows through the trigger electrode and the ground electrode, the initial plasma forms a discharge channel between the high-voltage electrode and the ground electrode, the capillary wall between the trigger electrode and the ground electrode is quickly ablated and ablated in the main discharge process, a large amount of thermal plasma is generated, a larger pressure is generated, and then high-temperature, high-density and high-speed thermal plasma flow 13 is formed at the nozzle of the capillary.

Because the pulse width 7 of the negative pulse is hundreds of nanoseconds, the negative pulse signal can be triggered by discharging on the trigger electrode 2 under the action of a capacitor, and the diode 9 prevents the pulse signal from being transmitted to the grounding resistor 10; in the ignition and arc striking stage, the discharge time is several microseconds, the isolating capacitor 8 isolates the discharge current, and the current flows to the ground through the diode 9 and the grounding resistor 10.

The diode and the grounding resistor can pass through large current, and the grounding resistor 10 is selected to have a larger value, and 80-120 ohms is taken.

In the main discharge stage, the current flows to the ground through the trigger electrode 2 and the ground electrode 3 respectively, but the ground resistance is much larger than the resistance of the plasma current, so the main current flows to the ground through the ground electrode 3, and the current on the trigger electrode 2 accounts for 0.8% -2% of the total current.

In addition, the ignition and arc ignition process of capillary discharge can be controlled by controlling the pulse width and the amplitude of the two power supplies and controlling the time sequence of the switch, so that the capillary discharge is safer, more stable, more efficient and more reliable. The time sequence control of the switch can control the starting time of the ignition and arc ignition process and adjust the discharge repetition frequency; the pulse width and amplitude control of the power supply can control the speed of the ignition and arc ignition process, so that the subsequent main discharge process is influenced, and the effects of adjusting the temperature, density and speed of the ejected thermal plasma flow are achieved.

By the time sequence control of the high-voltage pulse source and the switch on the negative trigger pulse, the working process of the capillary system is repeated under the condition that the switch is repeatedly opened and closed, so that the plasma flow with high frequency and high heat load is generated.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.