Plasma generator coaxial double-electrode liquid metal composite cooling system and method

Abstract

The application discloses a coaxial double-electrode liquid metal composite cooling system and method for a plasma generator, and the system comprises a coaxial electrode assembly, an anode cooling loop assembly, a cathode temperature equalizing assembly and a temperature control assembly. The coaxial electrode assembly comprises an inner cathode, an outer anode and an arc cavity formed by the cathode and the anode; the anode cooling loop assembly is composed of an anode built-in annular flow channel, a direct-current electromagnetic pump and a fin radiator to form a closed circulation pipeline filled with a liquid metal working medium; the cathode temperature equalizing assembly is provided with a porous capillary core and a vacuum sealing shell to form a vacuum phase change cavity filled with a same-source working medium; and the temperature control assembly collects electrode temperature through a temperature collecting element and adjusts the flow of the direct-current electromagnetic pump with the help of a PLC controller. The application overcomes the defects of low limit, easy leakage and cathode hot spot ablation of traditional water cooling heat dissipation, solves the problems of single traditional liquid metal cooling structure and lack of self-adaptive temperature control through anode liquid metal closed circulation cooling, cathode capillary vacuum phase change temperature equalizing and intelligent temperature control.

Description

Technical Field

[0001] This invention belongs to the field of thermal management technology for plasma ignition equipment, specifically relating to a coaxial dual-electrode liquid metal composite cooling system and method for a plasma generator. Background Technology

[0002] High-power plasma generators are core equipment for oil-free ignition and stable combustion under low load in coal-fired boilers of thermal power plants. During operation, the coaxially arranged anode and cathode electrodes continuously discharge arcs, generating extremely high heat flux densities. This makes the electrode surfaces prone to localized hot spots, and prolonged high-temperature operation can easily lead to electrode erosion and failure. Currently, the industry commonly uses pure water circulation cooling to dissipate heat from the plasma electrodes. However, traditional water cooling structures have low heat exchange efficiency and limited heat dissipation limits, making it difficult to meet the heat dissipation requirements of long-term continuous operation of high-power plasma generators of 350kW and above. Furthermore, water cooling systems often use rubber-sealed structures, resulting in poor pipeline sealing reliability and a high risk of leakage. If cooling water seeps into the furnace, it can easily cause safety accidents such as deflagration. In addition, traditional water cooling only achieves overall coarse cooling of the electrodes and cannot specifically eliminate the localized high temperatures caused by cathode arc spots, leading to rapid electrode erosion, frequent equipment maintenance, and poor operational stability. Existing liquid metal cooling solutions are often structurally simple, with only a unidirectional circulating cooling structure for the anode. They fail to incorporate the different heat load characteristics of the anode and cathode into a composite heat dissipation architecture, lack a cathode capillary phase change temperature equalization structure and an adaptive temperature control mechanism, and thus cannot simultaneously meet the requirements of efficient heat dissipation, leak-free safe operation, and long service life under high-power conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a coaxial dual-electrode liquid metal composite cooling system and method for plasma generators, in order to solve the technical defects of existing plasma generators using water cooling, such as low heat exchange limit, easy leakage leading to safety hazards, severe local high temperature ablation of the cathode, and the traditional liquid metal cooling scheme having a simple structure, lack of differentiated heat dissipation structure for anode and cathode, lack of adaptive temperature control mechanism, resulting in poor electrode heat dissipation effect, low operational safety, short equipment lifespan, and difficulty in adapting to stable operation under high power conditions.

[0004] To achieve the above objectives, this application provides the following technical solution: In a first aspect, this application provides a coaxial dual-electrode liquid metal composite cooling system for a plasma generator, comprising: A coaxial electrode assembly includes a cathode and an anode arranged coaxially, wherein the cathode is located inside the anode, and an arc cavity is formed between the cathode and the anode. An anode cooling circuit assembly includes an annular flow channel integrally formed on the anode wall, a DC electromagnetic pump, and a finned heat sink; the liquid outlet of the annular flow channel is connected to the liquid inlet of the DC electromagnetic pump, the liquid outlet of the DC electromagnetic pump is connected to the liquid inlet of the finned heat sink, and the liquid outlet of the finned heat sink is connected back to the liquid inlet of the annular flow channel to form a closed circulation pipeline, and the closed circulation pipeline is filled with a low melting point liquid metal working fluid. A cathode equalization assembly includes a porous capillary core in a groove on the back of the cathode and a vacuum-sealed shell. The porous capillary core is fixedly embedded in the groove on the back of the cathode. The vacuum-sealed shell is fixed to the back of the cathode and covers the outside of the porous capillary core. The vacuum-sealed shell and the cathode together form a vacuum phase change cavity. The vacuum phase change cavity is filled with a liquid metal working fluid of the same origin as the anode cooling circuit. The temperature control component includes a temperature acquisition element and a PLC controller fixedly mounted on the surfaces of the cathode and the anode. The temperature acquisition element is signal-connected to the PLC controller, and the PLC controller is electrically connected to the DC electromagnetic pump for acquiring temperature data to regulate the output flow rate of the electromagnetic pump.

[0005] In one optional embodiment, multiple annular flow channels are provided, and the multiple annular flow channels are evenly arranged along the circumference of the anode wall; The hydraulic diameter of the annular flow channel is 4mm to 8mm, and the cross-section is set as rectangular or circular.

[0006] In one optional embodiment, the porous capillary core is integrally formed by sintering copper powder; The porous capillary core has a porosity of 60% to 75% and an average pore size of 20 μm to 50 μm. The porous capillary core and the cathode groove are tightly bonded and fixed by hot pressing and sintering.

[0007] In one alternative embodiment, the vacuum-sealed housing is laser-welded to the back of the cathode.

[0008] In one alternative embodiment, the liquid metal working fluid is a gallium-based alloy.

[0009] In one alternative embodiment, the finned heat sink includes: Copper-aluminum composite fins and axial flow fans; The finned radiator adopts a copper-aluminum composite fin structure. The axial flow fan is mounted on the outside of the finned heat sink and is used to implement forced air cooling of the finned heat sink.

[0010] In one alternative embodiment, the temperature acquisition element includes an armored thermocouple; Multiple sets of the armored thermocouples are respectively arranged in the cathode spot region and the anode high-temperature region. The armored thermocouples are used to collect real-time temperature signals of the cathode and anode.

[0011] In one optional embodiment, the PLC controller has a built-in incremental PID control algorithm; The PLC controller adjusts the output flow of the DC electromagnetic pump in real time through the incremental PID control algorithm. The PLC controller adjusts the electromagnetic pump flow rate to match the real-time thermal load of the electrodes.

[0012] In one alternative embodiment, the temperature control component includes an audible and visual alarm; The PLC controller is preset with an electrode temperature limit threshold. When the collected temperature exceeds the limit threshold, the PLC controller triggers an audible and visual alarm and activates the plasma generator to shut down for protection.

[0013] A second aspect of this application provides a coaxial dual-electrode liquid metal composite cooling method for a plasma generator, the method being applied to the coaxial dual-electrode liquid metal composite cooling system for a plasma generator as described above, comprising: Beforehand, the closed circulation pipeline and the vacuum phase change cavity are filled with homologous gallium-based liquid metal working medium, and the vacuum phase change cavity is kept in a vacuum-sealed state. When the plasma generator is working, the working temperature of the cathode and anode is collected in real time through armored thermocouples, and the temperature signal is transmitted to the PLC controller in real time. The PLC controller uses a built-in incremental PID control algorithm to dynamically adjust the output flow of the DC electromagnetic pump according to the real-time heat load of the electrode, drive the liquid metal working fluid to circulate in a closed loop in the anode annular flow channel, and work with the finned heat sink and axial flow fan to complete the forced heat dissipation of the anode. A porous capillary core sintered and fixed on the back of the cathode is used to guide the liquid metal working fluid to undergo vacuum phase change heat transfer, thereby achieving uniform temperature heat dissipation across the entire cathode area. The PLC controller compares the measured temperature data with the preset temperature limit in real time. When the temperature exceeds the limit, it triggers an audible and visual alarm and links the plasma generator to shut down for protection.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. By using a closed-loop cooling system of liquid metal at the anode and a capillary vacuum phase change temperature equalization structure at the cathode, combined with intelligent temperature control components, it overcomes the shortcomings of traditional water cooling, such as low heat dissipation limit, easy leakage, and cathode hot spot erosion. It also solves the problems of the traditional liquid metal cooling solution having a simple structure and no adaptive temperature control, which greatly improves the overall heat dissipation efficiency and operational safety, and is suitable for the long-term stable operation of high-power equipment.

[0015] 2. The anode has multiple annular flow channels arranged evenly in the circumference, and the hydraulic diameter and cross-sectional structure of the channels are standardized. This solves the problems of uneven heat exchange, insufficient effective heat exchange area, and local heat accumulation in traditional cooling channels. It allows the liquid metal working fluid to evenly cover the anode wall, comprehensively improving the uniformity of anode heat exchange and heat dissipation efficiency, and meeting the heat dissipation requirements of high heat load on the anode under high power conditions.

[0016] 3. The porous capillary wick solves the defects of traditional cathodes, such as the lack of a dedicated temperature equalization structure, local high temperature caused by arc spots, and severe electrode ablation. The porous structure can efficiently guide the heat of liquid metal phase transformation, and the gapless bonding structure ensures rapid heat dissipation, effectively eliminating cathode hot spots and reducing electrode ablation loss.

[0017] 4. Laser welding is used to achieve a sealed connection between the shell and the cathode, eliminating the need for traditional rubber and threaded seals. This solves the problems of easy aging and leakage in traditional water-cooled systems, which can easily lead to furnace deflagration. The integrated welded seal has no vulnerable sealing parts, completely eliminating the risk of working fluid leakage and greatly improving the airtightness of the cooling system and its operational reliability under high-power conditions.

[0018] 5. Using gallium-based alloys as the cooling medium solves the defects of traditional water-cooled media, such as poor heat exchange performance, easy vaporization at high temperatures, and low heat dissipation limit. This medium has a low melting point, an extremely high boiling point, and excellent thermal conductivity. It can be adapted to both anode circulating heat exchange and cathode phase change heat dissipation conditions. It has stable performance under high temperature conditions, effectively improving the heat dissipation limit and operating condition adaptability of the entire cooling system.

[0019] 6. The copper-aluminum composite finned heat sink, combined with an axial fan for forced air cooling, solves the problems of low heat exchange efficiency, slow heat dissipation, and inability to match the efficient heat exchange rhythm of liquid metal in traditional heat dissipation structures. The composite finned structure has excellent thermal conductivity, and when combined with forced air cooling, it can quickly remove the heat of the circulating working fluid, ensuring continuous and efficient heat dissipation of the cooling circuit, and is suitable for continuous operation of high-power equipment.

[0020] 7. By precisely placing multiple sets of armored thermocouples in the high-temperature core areas of the anode and cathode, the shortcomings of traditional temperature measurement methods, such as single measurement point, inability to accurately capture changes in electrode heat load, and lagging temperature measurement data, are solved. The temperature signal of the entire electrode area can be collected in real time and accurately, providing accurate data support for subsequent intelligent temperature control and ensuring the accuracy and timeliness of heat dissipation regulation.

[0021] 8. By using the built-in incremental PID control algorithm in the PLC controller, the shortcomings of traditional cooling systems, such as lack of adaptive regulation function, fixed electromagnetic pump flow, inability to match the dynamic heat load of electrodes, insufficient heat dissipation redundancy, or energy waste, are solved. The working fluid circulation flow can be dynamically adjusted according to the real-time temperature of the electrodes to achieve heat dissipation on demand, taking into account both heat dissipation effect and equipment operating energy efficiency.

[0022] 9. An audible and visual alarm and linkage shutdown protection mechanism has been added, which solves the defects of traditional cooling systems, such as lack of over-temperature protection, easy damage to electrodes due to high temperature overload, and poor equipment operation safety. By monitoring and comparing preset temperature thresholds in real time, an alarm is quickly triggered and the system is shut down when the temperature exceeds the limit, effectively avoiding the risk of electrode high temperature ablation and equipment failure, and improving the system's safety protection capabilities. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of a coaxial dual-electrode liquid metal composite cooling system for a plasma generator provided by the present invention; In the diagram: 1. Cathode heat exchanger assembly; 2. Anode cooling circuit assembly; 3. Finned radiator; 4. DC electromagnetic pump. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] To address the technical deficiencies mentioned in the background section, this embodiment provides a coaxial dual-electrode liquid metal composite cooling system and method for plasma generators. It is mainly applied to high-power plasma ignition equipment in thermal power plants and is designed to meet the high heat load heat dissipation requirements of the anode and cathode of high-power plasma generators of 350kW and above.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1 As shown, in a first aspect of the present invention, a coaxial dual-electrode liquid metal composite cooling system for a plasma generator is provided, comprising a coaxial electrode assembly including a cathode and an anode coaxially mounted, the cathode being disposed inside the anode, and an arc cavity being formed between the cathode and the anode; an anode cooling circuit assembly 2 including an annular flow channel integrally formed on the anode wall, a DC electromagnetic pump 4, and a finned heat sink 3; the liquid outlet of the annular flow channel is connected to the liquid inlet of the DC electromagnetic pump 4, the liquid outlet of the DC electromagnetic pump 4 is connected to the liquid inlet of the finned heat sink 3, and the liquid outlet of the finned heat sink 3 is connected back to the liquid inlet of the annular flow channel to form a closed circulation pipeline, the inside of the closed circulation pipeline... The cathode is filled with a low-melting-point liquid metal working fluid; the cathode temperature equalization assembly 1 includes a porous capillary core and a vacuum-sealed shell in a groove on the back of the cathode. The porous capillary core is fixedly embedded in the groove on the back of the cathode. The vacuum-sealed shell is fixed to the back of the cathode and covers the outside of the porous capillary core. The vacuum-sealed shell and the cathode enclose a vacuum phase change cavity, which is filled with a liquid metal working fluid of the same origin as the anode cooling circuit; the temperature control assembly includes a temperature acquisition element and a PLC controller fixed on the surfaces of the cathode and anode. The temperature acquisition element is connected to the PLC controller. The PLC controller is electrically connected to the DC electromagnetic pump 4 to collect temperature data and regulate the output flow of the electromagnetic pump.

[0030] The coaxial electrode assembly includes a cathode and an anode arranged coaxially. The cathode is assembled entirely within the cavity of the anode, and the outer wall of the cathode and the inner wall of the anode are spaced apart to form a complete arc cavity. When the equipment is powered on, a high-voltage plasma arc is generated inside the arc cavity between the cathode and the anode. The arc continuously releases huge amounts of heat, making the arc spot area of ​​the cathode and the inner wall surface of the anode an area with ultra-high heat flux density, which is the main heat dissipation target of the entire cooling system.

[0031] The arrangement of the coaxial assembly can reduce the overall radial dimension of the plasma generator, making it suitable for the limited installation space of power plant boilers. At the same time, it ensures that the arc cavity shape is regular, the arc combustion is stable, and avoids arc deviation causing local overheating of the electrodes, which aggravates ablation and loss.

[0032] The system is equipped with an anode cooling circuit assembly 2, which is used to undertake the overall forced circulation heat dissipation function of the anode. The anode cooling circuit assembly 2 includes an annular flow channel integrally formed inside the anode wall, a DC electromagnetic pump 4, and a finned heat sink 3.

[0033] The annular flow channel is directly and integrally cast inside the anode metal wall without additional splicing pipelines, reducing the risk of leakage caused by pipeline connection gaps. The liquid outlet of the annular flow channel is connected to the liquid inlet of the DC electromagnetic pump 4, and the liquid outlet of the DC electromagnetic pump 4 is connected to the medium inlet of the finned heat sink 3. The medium outlet of the finned heat sink 3 is then connected to the liquid inlet of the annular flow channel through a return pipeline. All pipelines are connected end to end to form a complete closed-loop pipeline structure. The inside of the closed-loop pipeline is completely filled with low-melting-point liquid metal working fluid. The DC electromagnetic pump 4 provides circulation power to drive the liquid metal working fluid to continuously flow inside the anode wall, continuously carrying away the large amount of heat generated on the anode arc side.

[0034] In one optional embodiment, multiple annular flow channels are provided, which are evenly arranged along the circumferential direction of the anode wall. These channels are parallel to each other and equidistantly distributed within the inner wall region of the anode's circumferential wall. The hydraulic diameter of the annular flow channels is set to 4mm–8mm. The cross-section of a single annular flow channel can be either rectangular or circular; both cross-sectional forms can be flexibly selected according to the anode casting process.

[0035] Multiple evenly arranged annular flow channels can significantly increase the effective heat exchange contact area between the anode wall and the liquid metal working fluid, avoiding the accumulation of local heat on the anode due to insufficient heat exchange area of ​​a single flow channel; the hydraulic diameter in the range of 4mm to 8mm can balance the flow resistance of the liquid metal and the heat exchange contact area. If the hydraulic diameter is too small, it will significantly increase the delivery resistance of the DC electromagnetic pump 4 and increase the energy consumption of the equipment. If the hydraulic diameter is too large, it will reduce the turbulence intensity of the working fluid flow and weaken the convective heat transfer effect. 4mm to 8mm is the optimal range for gallium-based alloy working fluid.

[0036] Rectangular cross-section flow channels are easy to process and form, fitting the arc-shaped wall of the anode. Circular cross-section flow channels have no stress concentration dead corners inside, allowing for smoother flow of liquid metal. The cross-section form can be freely selected according to the requirements of the anode processing mold.

[0037] The finned heat sink 3, which is matched with the anode cooling circuit assembly 2, includes two supporting components: copper-aluminum composite fins and an axial flow fan. The main body of the finned heat sink 3 adopts a copper-aluminum composite fin structure. The copper material is in direct contact with the liquid metal working fluid pipeline. The ultra-high thermal conductivity of copper is used to quickly absorb the heat carried by the working fluid inside the pipeline. The aluminum fins increase the contact area with the air, reducing the overall weight and manufacturing cost of the heat sink.

[0038] An axial flow fan is mounted and fixed on the outside of the finned heat sink 3. The axial flow fan continuously delivers high-speed airflow to the finned surface, providing uninterrupted forced air cooling for the finned heat sink 3. When the high-temperature liquid metal working fluid flows through the internal pipes of the finned heat sink 3, the heat is rapidly conducted to the copper-aluminum composite fins. The forced airflow generated by the axial flow fan continuously removes heat from the fin surface, completing the cooling of the liquid metal working fluid. The cooled, low-temperature liquid metal working fluid then flows back into the annular flow channel inside the anode wall, completing the full heat exchange cycle. The forced air cooling combined with the copper-aluminum composite fin structure results in a heat dissipation efficiency far exceeding that of natural cooling, quickly controlling the temperature of the working fluid inside the anode heat exchange circuit within a safe range and ensuring the continuous heat dissipation capacity of the anode under high-power conditions.

[0039] The anode cooling circuit assembly 2 is powered by a DC electromagnetic pump 4. The DC electromagnetic pump 4 has no moving mechanical parts; it relies on electromagnetic induction to drive the liquid metal conductor working fluid for circulation. The entire assembly is completely connected to a closed circulation pipeline. Traditional mechanical water pumps have moving parts such as impellers and bearings, which are prone to wear, jamming, and leakage due to long-term immersion in high-temperature liquid metal. This solution uses the DC electromagnetic pump 4, which has no moving parts, eliminating the risk of mechanical wear failure. Combined with the all-metal closed pipeline structure, it achieves leak-free long-term circulation of the liquid metal working fluid, significantly extending the overall service life of the anode cooling circuit assembly 2 and reducing the frequency of routine maintenance of power plant equipment.

[0040] The cathode heat exchanger 1 is designed to address the problem of localized high temperatures in the cathode arc spot, achieving uniform heat dissipation through vacuum phase change over the entire cathode area. The cathode heat exchanger 1 includes a porous capillary core assembled inside a groove on the back of the cathode and a vacuum-sealed shell. An embedded groove structure is pre-formed on the back of the cathode, and the porous capillary core is fixedly embedded inside the groove. The vacuum-sealed shell is fixedly connected to the surface of the back of the cathode, completely covering the entire outer area of ​​the porous capillary core. The inner wall of the vacuum-sealed shell and the metal wall of the back of the cathode enclose each other to form a sealed vacuum phase change cavity. The vacuum phase change cavity is filled with a liquid metal working fluid of the same origin as the sealed circulation pipeline of the anode cooling circuit 2. The anode and cathode use the same heat exchange working fluid.

[0041] In one optional embodiment, the porous capillary core is prepared by copper powder sintering integral molding process. The overall porosity of the porous capillary core is controlled in the range of 60% to 75%, and the average pore size inside the porous capillary core is set to 20μm to 50μm. The porous capillary core is tightly bonded and fixed to the inner wall of the groove on the back of the cathode by hot pressing sintering process.

[0042] The porous capillary core formed by copper powder sintering possesses a continuous and interconnected capillary pore structure. Its porosity of 60%–75% ensures sufficient storage capacity for the liquid metal working fluid, while the average pore size of 20μm–50μm generates stable capillary adsorption force, continuously drawing the liquid metal working fluid into the vacuum phase change cavity and uniformly wetting the entire capillary core. The hot-pressing sintering process ensures a seamless fit between the porous capillary core and the inner wall of the cathode groove, eliminating contact thermal resistance caused by assembly gaps. The heat generated by the cathode arc can be rapidly conducted through the metal substrate to the interior of the porous capillary core. The liquid metal working fluid wetting the pores absorbs heat and undergoes a vaporization phase change. The vaporized metal vapor condenses and liquefies on the low-temperature wall of the vacuum phase change cavity, relying on the capillary force of the capillary core to flow back to the high-temperature heat-absorbing region, continuously circulating and undergoing phase change heat transfer. This rapidly eliminates localized hot spots in the cathode arc spot area, achieving overall cathode temperature homogenization and significantly reducing localized high-temperature ablation losses.

[0043] In one alternative embodiment, the vacuum sealing shell and the back contact surface of the cathode are connected by laser welding, eliminating the rubber sealing rings and threaded sealing structures commonly used in traditional water cooling systems. Laser welding enables the vacuum sealing shell and the cathode metal substrate to be fused and sealed as a whole, with no micro-gaps in the weld. The vacuum phase change cavity can maintain a high vacuum and sealed state for a long time. The vacuum environment significantly reduces the phase change saturation temperature of the liquid metal working medium and enhances the phase change heat transfer efficiency. At the same time, there are no easily damaged rubber seals, eliminating the risk of high-temperature aging, damage and leakage of seals. This completely eliminates the safety hazard of liquid metal working medium leaking into the furnace and causing deflagration, improving the operational safety and long-term reliability of the entire cooling system.

[0044] The low-melting-point liquid metal working medium filled in the closed-loop circulation pipeline of the anode cooling circuit assembly 2 and the vacuum phase change chamber of the cathode heat exchange assembly 1 is uniformly made of gallium-based alloy. The gallium-based alloy material itself has a melting point not exceeding 20℃, maintaining a liquid flow state at room temperature, and a boiling point not lower than 1500℃. It will not vaporize or boil and fail under the high-temperature conditions of thousands of degrees Celsius at the plasma generator electrodes. Its thermal conductivity is much higher than that of conventional water-cooling media such as pure water and ethylene glycol, significantly improving the heat exchange and dissipation limit, and meeting the long-term continuous heat dissipation requirements of high-power plasma generators of 350kW and above. The gallium-based alloy is chemically stable and does not easily corrode with copper, aluminum, stainless steel, or other electrode and pipeline metal substrates, preventing scale buildup and blockage of the pipeline inner walls. Long-term operation does not require frequent pipeline cleaning, reducing equipment maintenance workload. It is also compatible with two different heat exchange conditions: forced convection circulation heat exchange at the anode and vacuum capillary phase change heat exchange at the cathode, with one medium meeting the combined heat dissipation requirements of the anode and cathode.

[0045] The temperature control component is used for all control functions, including real-time acquisition of electrode temperature, adaptive adjustment of heat dissipation flow, and over-temperature safety protection. The temperature control component includes temperature acquisition devices fixedly installed on the cathode and anode surfaces, and a PLC controller. The temperature acquisition devices establish a signal connection with the PLC controller through a signal transmission line. The PLC controller is electrically connected to the DC electromagnetic pump 4 through a control line. After receiving the electrode temperature data transmitted in real time by the temperature acquisition devices, the PLC controller adjusts the output medium flow of the DC electromagnetic pump 4 according to the real-time temperature value to dynamically match the real-time heat load of the electrode and achieve heat dissipation on demand.

[0046] In one optional implementation, the temperature acquisition element inside the temperature control component is an armored thermocouple. The system is equipped with multiple sets of armored thermocouples, which are precisely arranged at two core high-temperature locations: the cathode arc spot area and the high-temperature area on the inner wall of the anode. The armored thermocouples collect real-time temperature signals from the cathode and anode surfaces and continuously transmit the temperature data to the PLC controller.

[0047] Armored thermocouples are resistant to high temperatures and arc radiation interference, enabling them to maintain stable temperature measurement in the high-temperature operating environment of plasma generators for extended periods. The multi-point, zoned temperature measurement structure can simultaneously capture the local hot spot temperature of the cathode and the overall wall temperature of the anode. The PLC controller can simultaneously acquire temperature change data across the entire anode and cathode region, avoiding the data lag and blind spots inherent in single-point temperature measurement, and providing accurate and comprehensive temperature data support for adaptive flow regulation.

[0048] In one optional implementation, the PLC controller has an internally built-in incremental PID control algorithm. During operation, the PLC controller adjusts the liquid metal output flow rate of the DC electromagnetic pump 4 in real time through the built-in incremental PID control algorithm. The PLC controller dynamically adjusts the circulation flow rate of the electromagnetic pump according to the real-time collected electrode temperature values, so that the liquid metal circulation flow rate matches the real-time heat load of the electrode.

[0049] When the output power of the plasma generator increases, the electrode heat load rises, and the measured temperature value increases, the incremental PID algorithm automatically increases the output flow of the DC electromagnetic pump 4, increases the heat exchange rate of liquid metal circulation, and enhances the heat dissipation capacity. When the equipment is operating at low load and the electrode temperature decreases, the algorithm automatically reduces the pump flow, reduces the useless power consumption of the equipment, and achieves a balance between heat dissipation performance and energy consumption. Unlike the fixed flow operation mode of traditional cooling systems, adaptive flow regulation improves heat dissipation adaptability and reduces the long-term energy consumption of the equipment.

[0050] In one optional implementation, the temperature control component is additionally equipped with an audible and visual alarm safety protection structure. The audible and visual alarm is electrically connected to the PLC controller, which pre-stores a preset electrode temperature limit threshold. The PLC controller continuously compares the temperature measurement data collected by the armored thermocouple with the internal preset temperature limit threshold in real time. When the collected real-time electrode temperature exceeds the preset limit threshold, the PLC controller immediately outputs a control signal. On the one hand, it triggers the audible and visual alarm to continuously emit audible and visual alarm signals, allowing on-site maintenance personnel to quickly identify the electrode over-temperature fault. On the other hand, it synchronously links the plasma generator host to perform a shutdown protection action, cutting off the arc power supply circuit and stopping arc heating, thus preventing the electrode from continuously overheating and causing serious ablation and equipment damage. This improves the fault safety protection capability of the entire system and enhances the fault tolerance of power plant equipment operation.

[0051] A second aspect of the present invention provides a coaxial dual-electrode liquid metal composite cooling method for a plasma generator, which is adapted to the coaxial dual-electrode liquid metal composite cooling system for a plasma generator described in any of the above embodiments, comprising: S1. Pre-filling and sealing operation of the medium in the early stage of equipment operation: Before the plasma generator is officially started and operated, homologous gallium-based liquid metal working medium is synchronously filled into the closed circulation pipeline of the anode cooling circuit component 2 and the vacuum phase change cavity of the cathode heat exchange component 1. After filling, the integrity of the laser welding seam between the vacuum sealing shell and the back of the cathode is re-inspected to ensure that the vacuum phase change cavity maintains a high vacuum sealing state for a long time, without medium leakage or vacuum degree decay, and to complete the pre-filling preparation of the heat dissipation medium of the equipment.

[0052] S2. Electrode Temperature Real-time Acquisition and Transmission Process: The plasma generator is powered on and started, and a plasma arc is generated inside the arc cavity to begin working. Multiple sets of armored thermocouples arranged in the cathode spot area and the anode high-temperature area synchronously and continuously collect the real-time working temperature of the cathode and anode surfaces. The armored thermocouples transmit the real-time temperature signal to the PLC controller without interruption, completing the real-time acquisition and uploading of electrode temperature data across the entire region.

[0053] S3. Anode adaptive forced circulation cooling process: The PLC controller calls the built-in incremental PID control algorithm to determine the current real-time heat load of the electrode based on the real-time received electrode temperature data, and dynamically adjusts the output flow rate of liquid metal of DC electromagnetic pump 4. DC electromagnetic pump 4 drives gallium-based liquid metal working fluid to continuously circulate in a closed loop inside multiple annular flow channels in the anode wall according to the regulated flow rate. When the high-temperature working fluid flows through the internal pipeline of finned heat sink 3, the axial flow fan mounted on the outside of finned heat sink 3 continuously outputs forced air cooling airflow, which quickly removes the heat carried by the working fluid through the copper-aluminum composite fins, completing the continuous forced convection cooling of the anode.

[0054] S4. Cathode Vacuum Capillary Phase Change Uniform Temperature Dissipation Process: The porous capillary core, hot-pressed and sintered in the groove on the back of the cathode, continuously pulls the gallium-based liquid metal working medium inside the vacuum phase change cavity to uniformly wet the entire capillary core by its own capillary adsorption force; the local high temperature heat generated in the cathode arc spot area is quickly conducted to the interior of the porous capillary core, the liquid metal working medium absorbs heat and undergoes vaporization phase change, the vapor condenses and liquefies on the low temperature inner wall of the vacuum phase change cavity, and the liquefied liquid metal flows back to the high temperature heat absorption area by the capillary force of the capillary core, continuously circulating phase change heat transfer, quickly eliminating local hot spots on the cathode, and achieving uniform temperature control and heat dissipation throughout the cathode.

[0055] S5. Electrode over-temperature safety linkage protection process: The PLC controller continuously compares the temperature measurement data uploaded by the armored thermocouple with the internally stored electrode temperature limit threshold in real time. Once the real-time temperature value exceeds the preset limit threshold, the PLC controller immediately executes dual protection actions. It first triggers the audible and visual alarm of the temperature control component to issue an audible and visual alarm prompt, and simultaneously outputs a shutdown control signal to link the plasma generator host to stop and cut off the arc power supply, stop the continuous heat generation of the electrode, avoid electrode high temperature ablation and equipment damage safety faults, and complete the entire system over-temperature emergency protection process.

[0056] The cooling method combines two heat dissipation modes: forced liquid metal circulation heat exchange at the anode and vacuum capillary phase change at the cathode. It is equipped with a multi-point precise temperature measurement, incremental PID adaptive flow control, and an integrated control process for over-temperature audible and visual alarm linkage shutdown protection. This standardized approach enables efficient, safe, and long-lasting cooling of the anode and cathode of high-power plasma generators.

[0057] This invention employs a composite heat dissipation architecture that combines closed-loop anodic liquid metal cooling with cathode vacuum capillary phase change temperature equalization. It works in conjunction with intelligent temperature control components to effectively overcome the multiple defects of traditional pure water cooling, such as low heat exchange limit, easy leakage of rubber seals in pipelines, severe local high-temperature ablation of cathode arc spots, and lack of differentiated heat dissipation between anode and cathode and lack of adaptive control mechanism in existing single-path liquid metal cooling.

[0058] This invention selects gallium-based alloys as the homogeneous cooling medium, which has a low melting point, high boiling point, and excellent thermal conductivity, significantly improving the upper limit of electrode heat dissipation. It can be stably adapted to the long-term continuous operation of high-power plasma generators of 350kW and above, and there is no problem of high-temperature vaporization failure of water-cooled medium.

[0059] The anode features multiple circumferentially evenly arranged annular flow channels, coupled with a DC electromagnetic pump with no moving parts and a copper-aluminum composite finned forced air-cooled radiator. This ensures ample heat exchange area and stable working fluid flow. The all-metal laser-welded sealing structure completely eliminates rubber seals, eradicating the safety hazard of furnace deflagration caused by media leakage. The cathode employs a copper powder sintered porous capillary core in conjunction with a vacuum phase change cavity. Relying on capillary force to drive the vacuum phase change of the working fluid, it can quickly eliminate localized hot spots on the cathode, effectively reducing the electrode ablation rate, extending electrode life, and reducing equipment maintenance frequency.

[0060] The system collects anode and cathode temperatures across the entire range using multi-point armored thermocouples and dynamically adjusts the electromagnetic pump flow rate using a built-in incremental PID algorithm in the PLC. This achieves adaptive, on-demand heat dissipation, balancing heat dissipation efficiency with energy consumption. A combined audible and visual alarm and shutdown protection mechanism is also included, providing timely warnings and cutting off equipment operation when electrodes overheat, thus enhancing equipment safety. The overall structure balances efficient heat dissipation, operational safety, and intelligent control, effectively meeting the long-term, heavy-load, and stable operation requirements of plasma ignition equipment in thermal power plant boilers.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A coaxial dual-electrode liquid metal composite cooling system for a plasma generator, characterized in that, include: A coaxial electrode assembly includes a cathode and an anode arranged coaxially, wherein the cathode is located inside the anode, and an arc cavity is formed between the cathode and the anode. The anode cooling circuit assembly includes an annular flow channel integrally formed on the anode wall, a DC electromagnetic pump, and a finned heat sink; The liquid outlet of the annular flow channel is connected to the liquid inlet of the DC electromagnetic pump, and the liquid outlet of the DC electromagnetic pump is connected to the liquid inlet of the finned heat sink. The liquid outlet of the finned heat sink is connected to the liquid inlet of the annular flow channel to form a closed circulation pipeline. The closed circulation pipeline is filled with a low melting point liquid metal working fluid. A cathode equalization assembly includes a porous capillary core in a groove on the back of the cathode and a vacuum-sealed shell. The porous capillary core is fixedly embedded in the groove on the back of the cathode. The vacuum-sealed shell is fixed to the back of the cathode and covers the outside of the porous capillary core. The vacuum-sealed shell and the cathode together form a vacuum phase change cavity. The vacuum phase change cavity is filled with a liquid metal working fluid of the same origin as the anode cooling circuit. The temperature control component includes a temperature acquisition element and a PLC controller fixedly mounted on the surfaces of the cathode and the anode. The temperature acquisition element is signal-connected to the PLC controller, and the PLC controller is electrically connected to the DC electromagnetic pump for acquiring temperature data to regulate the output flow rate of the electromagnetic pump.

2. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 1, characterized in that, Multiple annular flow channels are provided, and these multiple annular flow channels are evenly arranged along the circumference of the anode wall; The hydraulic diameter of the annular flow channel is 4mm to 8mm, and the cross-section is set as rectangular or circular.

3. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 1, characterized in that, The porous capillary core is integrally formed by sintering copper powder. The porous capillary core has a porosity of 60% to 75% and an average pore size of 20 μm to 50 μm. The porous capillary core and the cathode groove are tightly bonded and fixed by hot pressing and sintering.

4. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 1, characterized in that, The vacuum-sealed housing is connected to the back of the cathode by laser welding.

5. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 1, characterized in that, The liquid metal working fluid is a gallium-based alloy.

6. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 1, characterized in that, The finned heat sink includes: Copper-aluminum composite fins and axial flow fans; The finned radiator adopts a copper-aluminum composite fin structure. The axial flow fan is mounted on the outside of the finned heat sink and is used to implement forced air cooling of the finned heat sink.

7. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 1, characterized in that, The temperature acquisition device includes an armored thermocouple; Multiple sets of the armored thermocouples are respectively arranged in the cathode spot region and the anode high-temperature region. The armored thermocouples are used to collect real-time temperature signals of the cathode and anode.

8. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 1, characterized in that, The PLC controller has a built-in incremental PID control algorithm. The PLC controller adjusts the output flow of the DC electromagnetic pump in real time through the incremental PID control algorithm. The PLC controller adjusts the electromagnetic pump flow rate to match the real-time thermal load of the electrodes.

9. The coaxial dual-electrode liquid metal composite cooling system for a plasma generator according to claim 8, characterized in that, The temperature control component includes an audible and visual alarm; The PLC controller is preset with an electrode temperature limit threshold. When the collected temperature exceeds the limit threshold, the PLC controller triggers an audible and visual alarm and activates the plasma generator to shut down for protection.

10. A method for coaxial dual-electrode liquid metal composite cooling of a plasma generator, wherein the method is applied to the coaxial dual-electrode liquid metal composite cooling system of the plasma generator according to any one of claims 1-9, characterized in that, include: S1. Pre-fill the closed circulation pipeline and vacuum phase change cavity with homologous gallium-based liquid metal working medium, and maintain the vacuum seal of the vacuum phase change cavity. S2. When the plasma generator is working, the working temperature of the cathode and anode is collected in real time through the armored thermocouple, and the temperature signal is transmitted to the PLC controller in real time. The S3 PLC controller uses a built-in incremental PID control algorithm to dynamically adjust the output flow of the DC electromagnetic pump according to the real-time heat load of the electrode, driving the liquid metal working fluid to circulate in a closed loop in the anode annular flow channel, and working with the finned heat sink and axial flow fan to complete the forced heat dissipation of the anode. S4. A porous capillary core sintered and fixed on the back of the cathode is used to guide the liquid metal working fluid to undergo vacuum phase change heat transfer, thereby achieving uniform heat dissipation across the entire cathode area. The S5 and PLC controllers compare the measured temperature data with the preset temperature limit in real time. When the temperature exceeds the limit, an audible and visual alarm is triggered, and the plasma generator is shut down for protection.

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