A repeatable plasma jet device based on energetic material addition

Abstract

A repeatable plasma jetting device based on the addition of energetic materials includes: a metal ground electrode with an expanding nozzle and a capillary tube communicating with the expanding nozzle; a trigger needle electrode disposed opposite to the metal ground electrode; a metal wire located inside the capillary tube, with its two ends electrically connected to the metal ground electrode and the trigger needle electrode, respectively; the metal ground electrode has embedded jetting microcavities, which are centrally symmetrically distributed; each jetting microcavity includes: energetic material and an insulating ablation chamber; the jetting microcavity can be replaced after each triggering to achieve repeated jetting. This invention enhances the ablation gas generation and heat release of the insulating material by adding an energetic substance containing metal oxides to the insulating material jetting chamber, thereby improving the conductivity of the plasma, enhancing the plasma jetting performance, and achieving highly reliable triggering of the bypass gap switch.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage power equipment technology, specifically relating to a repeatable plasma jet device based on the addition of energetic materials. Background Technology

[0002] Ultra-high voltage (UHV) large oil-filled equipment, specifically including UHV converter transformers and power transformers, directly determines the safety and stability of the entire power system through its operational reliability. In actual operation, high-energy arc discharge events triggered by internal faults in UHV converter transformers can easily lead to frequent equipment explosions, causing not only huge economic losses but also adverse social impacts. To effectively prevent such explosions, ultra-fast switching technology is currently proposed to quickly bypass the fault current in the early stages of a fault, thereby suppressing the continued combustion of the internal arc and reducing the risk of the accident escalating. However, both traditional mechanical switches and power electronic switches have inherent defects and cannot meet the high reliability and high withstand voltage requirements of UHV scenarios. Against this backdrop, the scheme of bypassing and transferring the fault arc using a gas gap switch triggered by plasma jet has become a novel and promising technological approach in this field due to its high withstand voltage capability, simple structural design, and high operational reliability.

[0003] In view of the problems of poor triggering capability and low reliability of the bypass gap switch triggered by plasma jet for transformer explosion-proof combustion, there is an urgent need in the field for a repeatable plasma jet device based on the addition of energetic materials. Summary of the Invention

[0004] In view of the above-mentioned problems in the existing technology, the present invention adopts the following solution.

[0005] A repeatable plasma jet device based on the addition of energetic materials, comprising: A metal ground electrode, which is provided with an expanding nozzle and a capillary tube communicating with the expanding nozzle; The trigger pin electrode is positioned opposite to the metal ground electrode; A metal wire is located inside the capillary tube, and its two ends are electrically connected to the metal ground electrode and the trigger needle electrode, respectively. The metal ground electrode has embedded spray microcavities, which are centrally symmetrically distributed. Each spray microcavity includes an energetic material and an insulating ablation cavity. The spray microcavities can be replaced after each triggering to achieve repeated spraying.

[0006] Furthermore, the energetic material and the insulating ablation cavity are coaxially nested within the capillary to form a replaceable jet microcavity.

[0007] Furthermore, the expanding nozzle includes a neck and an expanding section, the neck being connected to the capillary.

[0008] Furthermore, the plasma jetting device also includes an epoxy pressure plate for pressing and fixing the various components of the device.

[0009] Furthermore, the trigger needle electrode has a "T" shaped structure, with its upper part used to press the metal wire and its lower part pressed onto the epoxy pressure plate.

[0010] Furthermore, the plasma jetting device also includes a fixing screw that passes through the epoxy pressure plate and is fixed to the metal ground electrode to provide uniform clamping force.

[0011] Furthermore, the energetic material is a mixture of metal oxides, hydrocarbon fuels, and reaction catalysts.

[0012] Furthermore, the material of the insulating ablation cavity is polytetrafluoroethylene, polyimide, or polyethylene.

[0013] Furthermore, the insulating ablation cavity is located outside the metal wire.

[0014] Furthermore, the energetic material is placed between the metal wire and the insulating ablation cavity.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: 1. By adding a mixed layer of metal oxide and hydrocarbon fuel in the middle of the high-gas-producing insulating ablation cavity material, taking PTFE as an example, the total heat release and rate of the mixed system reaction are increased, the jet motion characteristics of the plasma are improved, and the triggering performance of the gap switch is enhanced.

[0016] 2. The plasma jetting is controlled by changing parameters such as the type and proportion of material doping. This device features a detachable and replaceable structure, allowing for more flexible and adaptable performance testing and inspection. This invention is applicable to the explosion protection of large-capacity converter transformers. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the dimensions of a repeatable plasma jet device based on the addition of energetic materials in one embodiment of the present invention; Figure 2This is a repeatable plasma jetting device based on the addition of energetic materials in one embodiment of the present invention; Figure 3 This is a test method for a repeatable plasma jet device based on the addition of energetic materials in one embodiment of the present invention; Figure 4 This is an embodiment of the installation process of a repeatable plasma jet device based on the addition of energetic materials in one of the present invention; Figure 5 This is a schematic diagram illustrating the selection of the energetic material doping method in one embodiment of the present invention; Figure 6 This is a comparison of spray images of pure PTFEa and energetic material doped b in one embodiment of the present invention; Figure 7 This is a comparison of plasma jet height and velocity between pure PTFEa and energetic material doped b in one embodiment of the present invention; Figure 8 This is a schematic diagram of the trigger electrode of a repeatable plasma jet device based on the addition of energetic materials in one embodiment of the present invention. Detailed Implementation

[0019] The following will refer to the appendix. Figures 1 to 8 Specific embodiments of this disclosure are described in detail. While specific embodiments of this disclosure are shown in the accompanying drawings, it should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0020] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions of preferred embodiments of this disclosure are for the purpose of implementing the general principles of the specification and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure is determined by the appended claims.

[0021] To facilitate understanding of the embodiments of this disclosure, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of this disclosure.

[0022] In one embodiment, the present invention discloses a repeatable plasma jetting device based on the addition of energetic materials, comprising: A metal ground electrode, which is provided with an expanding nozzle and a capillary tube communicating with the expanding nozzle; The trigger pin electrode is positioned opposite to the metal ground electrode; A metal wire is located inside the capillary tube, and its two ends are electrically connected to the metal ground electrode and the trigger needle electrode, respectively. The metal ground electrode has embedded spray microcavities, which are centrally symmetrically distributed. Each spray microcavity includes an energetic material and an insulating ablation cavity. The spray microcavities can be replaced after each triggering to achieve repeated spraying.

[0023] This invention improves the ablation gas generation and heat release of the insulating material by adding an energetic substance containing metal oxide to the injection chamber of the insulating material, thereby enhancing the conductivity of the plasma and improving the injection performance of the plasma, and achieving highly reliable triggering of the bypass gap switch.

[0024] Furthermore, the energetic material and the insulating ablation cavity are coaxially nested within the capillary to form a replaceable jet microcavity.

[0025] Furthermore, the expanding nozzle includes a neck and an expanding section, the neck being connected to the capillary.

[0026] Furthermore, the plasma jetting device also includes an epoxy pressure plate for pressing and fixing the various components of the device.

[0027] Furthermore, the trigger needle electrode has a "T" shaped structure, with its upper part used to press the metal wire and its lower part pressed onto the epoxy pressure plate.

[0028] Furthermore, the plasma jetting device also includes a fixing screw that passes through the epoxy pressure plate and is fixed to the metal ground electrode to provide uniform clamping force.

[0029] Furthermore, the energetic material is a mixture of metal oxides, hydrocarbon fuels, and reaction catalysts.

[0030] Furthermore, the material of the insulating ablation cavity is polytetrafluoroethylene, polyimide, or polyethylene.

[0031] Furthermore, the insulating ablation cavity is located outside the metal wire.

[0032] Furthermore, the energetic material is placed between the metal wire and the insulating ablation cavity.

[0033] In another embodiment, the present invention discloses a repeatable plasma jetting device based on the addition of energetic materials, comprising: a metal ground electrode, an energetic material, an insulating ablation cavity, a trigger needle electrode, a metal wire, an epoxy pressure plate, and a fixing screw; wherein, The surface of the metal ground electrode has an expanding nozzle, and millimeter-sized capillaries are symmetrically arranged in the metal ground electrode; a metal wire is fixed in the capillary, with both ends connected to the metal ground electrode and the trigger needle electrode. The metal ground electrode has embedded spray microcavities that are centrally symmetrically distributed. The spray microcavities are composed of energetic materials and insulating ablation chambers. The spray microcavities can be replaced after each triggering to achieve repeated spraying.

[0034] The insulating ablation chamber is located outside the metal wire; the energetic material, which is composed of metal oxide and hydrocarbon fuel doped, is placed between the metal wire and the insulating ablation chamber; the epoxy pressure plate is used to press and fix the components of the device; the fixing screw passes through the epoxy pressure plate and is fixed below the metal ground electrode.

[0035] In another embodiment, the present invention discloses a repeatable plasma jetting device based on the addition of energetic materials, suitable for plasma triggering of bypass gap switches in ultra-high voltage converter transformers, comprising: a metal ground electrode 1, an energetic material 2, an insulating ablation cavity 3, a triggering needle electrode 4, a metal wire 5, an epoxy pressure plate 6, and a fixing screw 7; wherein, The metal ground electrode 1 is cylindrical in shape, with a diameter of approximately 100mm and a height of approximately 30mm at the lower end. The upper end extends 15mm to each side, and the upper edge is rounded with a chamfer radius of 5-8mm to reduce electric field non-uniformity and prevent accidental discharge to the high-voltage side from the edge of the metal ground electrode. The height of the upper ground electrode is approximately 15mm. The overall size of the ground electrode should be kept as compact as possible while still allowing the spray cavity to be placed. The metal ground electrode is made of a metal material such as copper with good ablation resistance and high conductivity. A threaded hole is provided at the bottom for fixing the screw 7 for connection.

[0036] An expanding nozzle 11 is formed on the surface. The neck length of the expanding nozzle is about 3 mm, the inner diameter is 2-3 mm, the outer diameter is 5 mm, and the nozzle length is about 5 mm. The nozzle diameter is set to 2-3 mm to increase the capillary pressure while minimizing the kinetic energy loss caused by plasma friction against the tube wall. The outer diameter of the nozzle is set to 5 mm. The overall shape of the nozzle is a straight hole with a length of 3 mm plus an expanding hole with a length of 5 mm. This design can optimize the flow field distribution of plasma inside the capillary and after ejection to a large extent, thereby improving the performance of the ejection device.

[0037] Two capillaries 12, each 2-3 mm in diameter and approximately 20 mm in length, are symmetrically arranged at the center of the ground electrode. These capillaries are used to increase the pressure within the capillaries while simultaneously reducing the kinetic energy loss and mass loss of the plasma jet. The capillary diameter is set at 2-3 mm for the same reason. The length is 20 mm because the metal wire length is the same as the capillary length. If the metal wire is too long, the impedance will be too high, consuming too much energy, reducing the energy available for arc discharge to ablate the microcavity, resulting in weaker plasma jet performance. Conversely, if the metal wire is too short, the heat generated by combustion will be too low, resulting in insufficient ablation of the microcavity, lower plasma concentration, weaker performance, and ultimately, poorer device performance.

[0038] The capillary tube contains a metal wire with two ends connected to the metal ground electrode and the trigger needle electrode. The two ends are welded and fixed to the bottom of the metal ground electrode 1 and the top of the trigger needle electrode 4, respectively, to ensure good electrical contact.

[0039] Under the injection of pulsed energy, the metal wire undergoes an electrical explosion, generating a high-temperature, high-density, and highly conductive initial plasma. The metal wire is made of metals such as copper, aluminum, and zinc, which have low ionization energy, high conductivity, and high exothermic reaction. The diameter of the metal is 100μm to 700μm, the number of metal wires is 1 to 5, and the length of the metal wire is 20 to 30mm.

[0040] The trigger electrode 4 has a "T" shaped structure. The upper cylinder has a height of about 5-15mm and a diameter of 8-10mm, while the lower cylinder has a height of about 20mm and a diameter of 6-10mm. The upper cylinder of the trigger electrode 4 is used to press the metal wire, and the lower cylinder is pressed onto the epoxy pressure plate.

[0041] The trigger pin has an M5 internal thread hole with a depth of 15mm at the bottom for trigger pulse wiring. The "umbrella-shaped" cylindrical structure between the upper and lower cylinders has a diameter of 15mm and a height of 6mm. The trigger pin is made of a metal material with strong ablation resistance and high conductivity, such as copper. As the pulse energy input end, it together with the metal wire 5 and the metal ground electrode 1 form a discharge circuit.

[0042] The energetic material 2 is a hollow cylinder, tightly fitted on the outside of the metal wire 5, located between the insulating ablation cavity 3 and the metal wire 5; the inner diameter is 2~3mm, the height is 5~20mm, and the outer diameter is 4~8mm.

[0043] The energetic material consists of metal oxides, hydrocarbon fuels, and a small amount of reaction catalyst. The metal oxides are selected from oxides with strong reducing properties and high heat of reaction, such as CuO and Al₂O₃. The hydrocarbon fuels are selected from materials with high gas yield per unit volume and low combustion temperature, such as sucrose. The reaction catalysts are selected from metal catalysts such as Al and Mg that can catalyze the reaction between metal oxides and hydrocarbon fuels. The proportion of metal oxides is 20%~30%, the proportion of high-gas-producing hydrocarbon fuels is 30%~70%, and the proportion of reaction catalysts is 5%~10%.

[0044] The energetic material rapidly decomposes under the high temperature generated by the electric explosion of the metal wire, releasing a large amount of gas and heat, which enhances the pressure and plasma ionization level inside the cavity.

[0045] The insulating ablation cavity is a hollow cylinder, fitted on the outside of the energetic material 2. Its inner diameter is about 1 mm larger than the outer diameter of the energetic material, ranging from 5 to 9 mm, so that the energetic material fits tightly inside the insulating ablation cavity. Its outer diameter is 14 to 20 mm, and its height is 20 to 30 mm. When heated, the insulating ablation chamber undergoes ablation and decomposition, generating small molecule gases such as C2F4, which further increases the gas pressure within the chamber and the plasma jet velocity. The insulating ablation chamber further decomposes and generates heat under the heat released from the burning metal wire, producing a large amount of easily ionized small molecule gases, further increasing the gas pressure within the capillary, thereby improving the plasma jet performance and conductivity.

[0046] The insulating ablation chamber is made of insulating materials such as PTFE, PI, and PE, which have high ablation gas generation performance, high thermal stability, and strong resistance to electric arc ablation.

[0047] The epoxy pressure plate is a ring-shaped plate, cylindrical in shape, approximately 150mm in diameter and 20mm thick. Four 10mm diameter through holes are formed on the epoxy pressure plate corresponding to the threaded holes of the ground electrode for connecting the ground electrode and the epoxy pressure plate with a fixing screw. Five 13.5mm diameter through holes are formed on the epoxy pressure plate corresponding to the jet microcavity 9 for passing the trigger needle electrode. The "umbrella-shaped" structure in the middle of the trigger needle ensures tight contact between the epoxy plate, the metal ground electrode, the jet microcavity 9, and other structures. The upper part of the trigger needle is in close contact with the metal wire. The epoxy pressure plate is pressed onto the lower cylinder of the trigger needle electrode 4, ensuring tight contact between it and the metal wire 5, the energetic material 2, the insulating ablation cavity 3, and the metal ground electrode 1, preventing plasma side leakage.

[0048] The fixing screws are symmetrically arranged, pass through the epoxy pressure plate 6 and are screwed into the threaded hole at the bottom of the metal ground electrode 1, providing uniform clamping force and ensuring the structural stability and electrical contact reliability of the entire device.

[0049] Pulsed energy is injected into metal wire 5 through trigger needle electrode 4, causing metal wire 5 to undergo an electrical explosion and generate initial plasma. The high temperature released in this process rapidly excites the energetic material 2 to undergo an exothermic decomposition reaction, generating a large amount of gas and heat, which further drives the ablation of the insulating ablation cavity 3 to produce gas. The three form an "electro-thermal-chemical" energy chain amplification mechanism, significantly increasing the total energy and jet kinetic energy of the plasma.

[0050] Energetic material 2 and insulating ablation chamber 3 form a double-layer nested structure, creating a high-pressure gas accumulation chamber. When the gas is ejected through the expanding nozzle 8, the neck and expansion section structure of the nozzle optimizes the flow field, reduces kinetic energy loss, and improves the density, velocity, and directionality of the plasma jet.

[0051] The uniform clamping force provided by the epoxy pressure plate 6 and the fixing screw 7 ensures that all components of the device remain in their original assembled state after each trigger. After triggering, the energetic material 2 and the insulating ablation cavity 3 can be replaced as a whole as an integrated microcavity module without disassembling the ground electrode 1 or the trigger pin electrode 4. Only the wiring position of the external trigger pulse terminal needs to be changed to achieve rapid reuse.

[0052] In another embodiment, the present invention discloses a repeatable plasma jetting device based on the addition of energetic materials, comprising: a metal ground electrode, an energetic material, an insulating ablation cavity, a trigger needle electrode, a metal wire, an epoxy pressure plate, and a fixing screw; wherein, The metal ground electrode has millimeter-scale capillaries symmetrically arranged around its center, and an expanding nozzle is attached to the surface of the ground electrode to generate a plasma jet; specifically, it includes: 1) Plasma Generation Stage: When the trigger pulse is applied to the trigger needle electrode, a large pulse current flows through the low-impedance circuit where the metal wire is located. The instantaneously injected high-density energy causes the temperature of the metal wire to rise sharply and an electrical explosion occurs. This process involves a phase transition from solid-state heating to melting, then to liquid-state heating, vaporization, and finally plasma, generating dense hot metal vapor plasma. This forms an arc channel connecting the ground electrode and the trigger electrode. The high temperature generated by the arc channel and the electrical explosion of the aluminum wire causes the insulating material (PTFE) cavity to vaporize and dissociate, forming gaseous plasma. Simultaneously, the radiation and shock waves generated by the electrical explosion cause a certain degree of ionization of the gas molecules. Since the discharge process lasts on the order of tens of microseconds, the capillary channel can be approximated as being in an adiabatic state. Therefore, the generated plasma is in a high-temperature, high-pressure state within the capillary channel, creating a huge pressure difference with the outside of the capillary.

[0053] 2) Plasma jet development stage: Under the action of the pressure difference inside and outside the capillary channel, the plasma is ejected at high speed and continues to develop forward. The speed gradually decreases. In this process, the plasma diffusion is mainly driven by the density gradient, spreading from the area with higher plasma density to the area with lower density. The plasma jet and development process is affected by the nozzle structure and gas pressure.

[0054] A metal wire is fixed in a capillary tube, with metal ground electrodes and trigger needle electrodes connected at both ends. When pulse energy is injected, the metal wire explodes to generate initial plasma. The insulating ablation chamber further decomposes and generates gas under the condition of a large amount of exothermic combustion of the metal wire. Energetic material is placed between the metal wire and the insulating ablation chamber, and decomposes upon heating to generate a large amount of gas and heat. An epoxy pressure plate is used to press and fix the various parts of the injection device. The epoxy pressure plate and the metal ground electrode are connected by a fixing screw to prevent plasma side leakage.

[0055] Preferably, the metal ground electrode has symmetrical slots inside for accommodating the jetting microcavities (energetic material, insulating ablation cavity, trigger needle electrode, and metal wire). Each jetting microcavity is composed of the energetic material, insulating ablation cavity, trigger needle electrode, and metal wire, with the insulating ablation cavity and energetic material nested within each other. After each trigger, the jetting microcavities can be replaced without disassembly, enabling repeated jetting. The jetting microcavities are composed of the insulating ablation cavity, energetic material, metal wire, and trigger needle electrode, forming a unified whole. "Replaceable" means that the size, type, and content of the energetic material are adjustable. Microcavities with different energetic material structures can be pre-installed within the same ground electrode, and the internal dimensions (inner diameter, internal height, etc.) of the corresponding insulating cavity can also be adjusted accordingly. However, only materials with good performance should be selected for the insulating cavity and the parameters of the metal wire.

[0056] The two ends of the metal wire are welded to the metal ground electrode and the trigger pin, ensuring reliable and consistent "close contact" between the two ends of the metal wire and the ground electrode and trigger pin electrode. Furthermore, the epoxy pressure plate limits and fixes the components, ensuring that their relative positions do not change. Since the trigger pin has a pre-installed terminal for the trigger pulse, after each triggering cycle, the microcavity can be replaced simply by changing the position of the trigger pulse terminal.

[0057] Preferably, the metal ground electrode is a metal material such as copper with good ablation resistance and high conductivity. The diameter of the lower cylinder is about 100mm and the height is about 30mm. The upper end extends 15mm to each side, the upper edge is rounded, the chamfer radius is 5~8mm, and the height of the upper ground electrode is about 15mm.

[0058] Preferably, the surface of the metal ground electrode has an expanding nozzle, which can be used to improve the plasma flow field distribution; millimeter-level capillaries are symmetrically arranged inside the ground electrode to increase the internal pressure of the cavity and further reduce the kinetic energy and mass loss of the plasma jet. Preferably, the neck length of the expanding nozzle is about 3mm, the inner diameter is 2-3mm, the outer diameter is about 5mm, and the nozzle length is about 5mm.

[0059] Preferably, a metal wire with metal ground electrode and trigger needle electrode at both ends is fixed in the capillary tube, which undergoes an electrical explosion when pulse energy is injected, generating a high-temperature, high-pressure, and highly conductive initial metal plasma. Preferably, the metal wire is made of metals such as copper, aluminum, and zinc, which have low ionization energy, high conductivity, and high exothermic reaction. The diameter of the metal is 100μm to 700μm, the number of metal wires is 1 to 5, and the length of the metal wire is 20 to 30mm.

[0060] Preferably, the insulating ablation cavity further decomposes and generates heat under the heat released by the burning of the metal wire, producing smaller molecule gases that are more easily ionized, further increasing the gas pressure in the capillary and the overall ionization degree of the plasma, thereby improving the plasma's jetting performance and conductivity. Preferably, the insulating ablation cavity should be made of insulating materials such as PTFE, PI, and PE, which have high ablation gas generation performance, high thermal stability, and strong resistance to electric arc ablation.

[0061] Preferably, the insulating ablation cavity is a hollow cylinder with an inner diameter of about 5-9 mm, an outer diameter of 14-20 mm, and a height of 20-30 mm. Preferably, the energetic material is composed of metal oxides, hydrocarbon fuels, and a small amount of reaction catalyst. The metal oxides are selected from oxides with strong reducing properties and high heat of reaction, such as CuO and Al₂O₃. The hydrocarbon fuels are selected from materials with high gas yield per unit volume and low combustion temperature, such as sucrose. The reaction catalysts are selected from metal catalysts such as Al and Mg that can catalyze the reaction between the metal oxides and hydrocarbon fuels. The energetic material is pre-pressed, and both the energetic material and the insulating ablation microcavity are processed into corresponding shapes and sizes before being integrally inserted.

[0062] Preferably, the proportion of metal oxides in the energetic material is 20%~40%, the proportion of high-gas-producing hydrocarbon fuel is 50%~70%, and the proportion of reaction catalyst is 5%~10%. Metal oxides act as auxiliary oxidants, providing oxygen to react with hydrocarbon fuels in a redox reaction that releases heat. They also act as heat carriers, absorbing the energy from the filament explosion and rapidly transferring it to surrounding materials. Some metal oxides (such as Fe₂O₃ and CuO) also have catalytic effects. When the metal oxide content is below 20%, insufficient oxidant leads to incomplete combustion of hydrocarbon fuels, significantly reducing the heat released and failing to effectively heat PTFE decomposition to generate more plasma. Simultaneously, incompletely burned hydrocarbon fuels form carbon deposits, reducing plasma conductivity. When the metal oxide content is above 40%, it excessively dilutes the proportion of hydrocarbon fuels, leading to a decrease in total energy density. Furthermore, metal oxides themselves do not produce gas; excessive amounts significantly reduce the system's total gas production, thereby weakening the plasma's jet thrust.

[0063] High-yield hydrocarbon fuels serve as the primary energy source and gas-generating agent. They react with the oxidant to release a large amount of heat (up to 5000-8000 J / g) and gases (such as CO2, H2O, H2, etc.), dramatically increasing the pressure within the microcavity and propelling the plasma at high speed. Simultaneously, the carbon particles produced by the decomposition of hydrocarbon fuels enhance the plasma's radiation absorption capacity. When the hydrocarbon fuel content is below 50%, the system's total energy output and gas production are insufficient to create a sufficient pressure gradient to accelerate the plasma, resulting in a minimal increase in plasma ejection velocity. When the hydrocarbon fuel content exceeds 70%, the oxidant is severely insufficient, leading to incomplete combustion and the production of large amounts of free carbon and unreacted hydrocarbon gases. These substances deposit on the inner wall of the microcavity, blocking the discharge channels and reducing the plasma's ionization and conductivity.

[0064] The reaction catalyst is used to lower the activation energy of the redox reaction, enabling the energetic material to react rapidly and synchronously at the high temperature generated by the filament explosion. It also regulates the reaction rate, preventing excessively vigorous reactions that could lead to microcavity rupture. When the catalyst content is below 5%, the catalytic activity is insufficient, the reaction initiation is delayed and the rate is slow, and the energy release is out of sync with the filament explosion, failing to effectively enhance the initial plasma ejection velocity. When the catalyst content is above 10%, the catalytic effect reaches saturation; further increases will not significantly improve the reaction rate; instead, they will dilute the energy density of the energetic material, reducing the total gas production and energy output.

[0065] Preferably, the high-gas-producing composition is: metal oxides: 25% (Fe2O3), high-gas-producing hydrocarbon fuel: 65% (polyethylene), and reaction catalyst: 10% (CuO). This composition has the highest proportion of hydrocarbon fuel and the largest gas production (up to 1200 L / kg), enabling the generation of higher injection pressures; however, due to the relatively insufficient oxidant, the combustion efficiency is slightly lower (approximately 85%), and energy release is slightly slower.

[0066] Preferably, the rapid energy release component scheme is as follows: metal oxide: 35% (CuO), high-gas-producing hydrocarbon fuel: 55% (polyethylene), and reaction catalyst: 10% (MnO2). The higher proportion of oxidant and catalyst results in rapid reaction initiation and rapid energy release, perfectly synchronized with the explosion time of the metal wire; however, the gas production is slightly lower (approximately 900 L / kg), and the injection pressure is slightly lower.

[0067] Preferably, the balanced performance is as follows: metal oxide: 30% (CuO), high-gas-producing hydrocarbon fuel: 60% (sucrose), and reaction catalyst: 10% (aluminum powder). The proportions of each component are balanced, resulting in high combustion efficiency (approximately 95%), moderate energy release rate, and high levels of gas production and injection speed; thus, the overall performance is optimal.

[0068] Preferably, the energetic material is tightly fitted around the outside of the metal wire 5, located between the insulating ablation cavity 3 and the metal wire 5; the energetic material is a hollow cylinder with an inner diameter of 2-3 mm, a height of 5-20 mm, and an outer diameter of 4-8 mm. Preferably, the epoxy pressure plate and the fixing screw are used to ensure the tight pressing of each component of the injection device, mainly to ensure good contact between the metal wire and the ground electrodes and trigger electrodes at both ends, so as to ensure that the pulse energy can be effectively deposited on the metal wire when the trigger occurs, causing the metal wire to explode and change phase to generate plasma, and also to prevent the side leakage of the plasma jet.

[0069] Preferably, the trigger needle electrode has a "T" shaped structure, with the upper cylinder having a height of about 5-15mm and a diameter of 8-10mm, the lower cylinder having a height of about 20mm and a diameter of 6-10mm, and the trigger needle having an M5 internal thread hole with a depth of 15mm at the bottom. The "umbrella-shaped" cylindrical structure between the upper and lower cylinders has a diameter of 15mm and a height of 6mm.

[0070] In another embodiment, the present invention also provides a testing method for a repeatable plasma jet device based on the addition of energetic materials, comprising: Step S100: Based on the determined type and proportion of metal oxides and hydrocarbon fuels in the energetic material, select the appropriate electrode material and trigger device material combination according to the determined parameters, and then install and connect the trigger device to the external circuit. Step S200: A μF-level capacitor is connected in parallel between the ground electrode and the high-voltage electrode of the jet device to maintain the gap voltage, control the discharge time of the pulse discharge circuit, inject pulse energy into the microcavity metal wire to generate plasma, and the pulse trigger signal is used to trigger the oscilloscope to record voltage and current waveforms and the high-speed camera to record the development process of plasma; Step S300: Measure the parallel capacitor voltage between the electrodes using a high-voltage probe, measure the capacitor discharge current using a Pearson coil, and simultaneously record the plasma development process using a high-speed camera.

[0071] Preferably, step S100 specifically includes: S101. The material of the injection chamber in the triggering device is added to the mixed material layer for embedding based on the optimized and improved technology to obtain a double-layer material injection chamber structure. The injection chamber, trigger electrode, metal wire and ground electrode are assembled by combining epoxy pressure plate and fixing screw. S102. Place the injection device inside a high-pressure SF6 sealed pressure vessel. The pressure vessel has a built-in high-pressure electrode, and a μF-level capacitor is connected in parallel between the electrode of the injection device and the ground electrode of the injection device to maintain the gap voltage. S103. After evacuating the inside of the tank to a vacuum, connect it to an SF6 high-pressure gas tank for inflation until the tank maintains a high-pressure environment of 0.5MPa.

[0072] In another embodiment, the present invention discloses a repeatable plasma jet device based on the addition of energetic materials, wherein the structural dimensions are shown in the schematic diagram. Figure 1 As shown, a test platform for the device is built based on this structure, such as... Figure 2 As shown, it includes a high-voltage SF6-filled insulation gap switch device, and a measurement circuit combining optical and electrical diagnostics; the device test process diagram is shown below. Figure 3 As shown, the process includes steps such as device assembly, triggering injection, and result analysis. The specific flow of the device assembly steps is as follows: Figure 4 As shown.

[0073] The plasma jet performance can be optimized by changing parameters such as the type and proportion of energetic material doping, thereby enabling the testing of device performance, such as... Figure 5 As shown in Figure 5, the adjustable parameters of the energetic material in the jet microcavity are as follows: Label 11 represents the axial length adjustment dimension of the energetic material, which can be adjusted by changing the overall height of the hollow cylindrical energetic material to adjust the total amount of reaction medium; Label 12 represents the inner and outer diameter and wall thickness adjustment dimensions of the energetic material, which can be adjusted by changing the radial thickness to adjust the contact area between the energetic material and the metal wire and the insulating ablation cavity; Label 13 represents the component doping adjustment dimension, which can be used to change the type and mass ratio of metal oxides, hydrocarbon fuels, and catalysts.

[0074] The injection device is placed inside a high-pressure SF6 sealed pressure vessel. The pressure vessel contains a high-pressure plate electrode, and a μF-level capacitor is connected in parallel between the ground electrode of the injection device and the high-pressure plate electrode to maintain the gap voltage.

[0075] The pulse waveform generated by the pulse capacitor discharge causes the metal wire between the trigger electrode and the ground electrode to explode due to energization. The phase transition generates a large amount of high-temperature, high-density plasma. At the same time, the discharge ablates and melts the capillary wall, enhancing the ionization of the plasma. The generated plasma is rapidly ejected with the airflow, and the distorted electric field even penetrates the gap to complete the triggering and conduction of the gap.

[0076] In the signal detection circuit, the trigger signal simultaneously acts on the oscilloscope's trigger reading, measuring the voltage change between gaps in the circuit through a high-voltage probe, and measuring the current change caused by capacitor discharge through a Pearson coil; at the same time, the trigger signal controls a high-speed camera to record and photograph the plasma development process inside the gap through the tank's observation window.

[0077] During the experimental results processing, the voltage and current measured by the high-voltage probe and Pearson coil were analyzed to determine the discharge status of the capacitor and the voltage change between the gaps, thereby determining whether the gaps were connected. High-speed camera footage was captured and recorded frame by frame, comparing the plasma ejection patterns of a pure PTFE microcavity and one with added energetic materials at the same time. The ejection height and velocity information at the same time point were extracted from the ejection images to further compare the ejection performance.

[0078] Figure 6 and Figure 7 In Figure a, the insulating ablation cavity is made of PTFE without the addition of any energetic material; Figure b shows a hollow cylindrical energetic material with the above structure, formed by pressing and processing a mixture of sucrose (hydrogen fuel), copper oxide (metal oxide), and aluminum powder (catalyst) in a mass ratio of 6:3:1. Figure 6 A comparison of plasma jet images under different structures was conducted. A comparison of plasma jet images from 8 to 169 μs after triggering showed that the jet device incorporating energetic materials exhibited faster plasma development and a longer duration. Figure 7 By comparing the plasma motion characteristics under different structures using the jet height and jet velocity information, it can be found that the jet device with the addition of a replaceable energetic material composite cavity has a relatively significant enhancement in both plasma jet height and velocity compared to the pure PTFE jet cavity, proving the effectiveness of adding energetic materials.

[0079] Implementation Results: This repeatable plasma jetting device based on the addition of energetic materials adopts a replaceable composite material layering method for the jetting chamber, which optimizes the energy release rate and total amount of the mixed system, improves the jetting speed and height of the plasma, and enhances the degree of ionization. This optimizes the triggering performance of the gap switch and provides a reliable solution for the explosion-proof technology of large oil-filled equipment, such as UHV converter transformers.

[0080] The above description is an embodiment of the repeatable plasma jet device based on the addition of energetic materials. The system described is a preferred system and should not be construed as a limitation on the technical solution of this invention. Those skilled in the art, based on the disclosure of this application, can add, reduce, or combine the disclosed technical features in the above general description and specific embodiments, including the examples, without departing from the constituent elements of the invention, to form other technical solutions within the scope of protection of this application.

Claims

1. A repeatable plasma jetting device based on the addition of energetic materials, characterized in that, include: A metal ground electrode, which is provided with an expanding nozzle and a capillary tube communicating with the expanding nozzle; The trigger pin electrode is positioned opposite to the metal ground electrode; A metal wire is located inside the capillary tube, and its two ends are electrically connected to the metal ground electrode and the trigger needle electrode, respectively. The metal ground electrode has embedded jetting microcavities, which are centrally symmetrically distributed; each jetting microcavity includes: an energetic material and an insulating ablation cavity. The injection microcavity can be replaced after each triggering to achieve repeated injection.

2. The plasma jetting device according to claim 1, characterized in that, Preferably, the energetic material and the insulating ablation cavity are coaxially nested within the capillary to form a replaceable jet microcavity.

3. The plasma jetting device according to claim 1, characterized in that, The expanding nozzle includes a neck and an expanding section, the neck being connected to the capillary.

4. The plasma jetting device according to claim 1, characterized in that, Also includes: Epoxy pressure plates are used to press and fix the various components of the device.

5. The plasma jetting device according to claim 4, characterized in that, The trigger needle electrode has a "T" shaped structure, with the upper part used to press the metal wire and the lower part pressed onto the epoxy pressure plate.

6. The plasma jetting device according to claim 4, characterized in that, Also includes: A fixing screw passes through the epoxy pressure plate and is fixed to the metal ground electrode to provide uniform clamping force.

7. The plasma jetting device according to claim 1, characterized in that, The energetic material is a mixture of metal oxides, hydrocarbon fuels and reaction catalysts.

8. The plasma jetting device according to claim 1, characterized in that, The insulating ablation cavity is made of polytetrafluoroethylene, polyimide, or polyethylene.

9. The plasma jetting device according to claim 2, characterized in that, The insulating ablation cavity is located outside the metal wire.

10. The plasma jetting device according to claim 2, characterized in that, Energetic material is placed between a metal wire and an insulating ablation cavity.

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