Arc simulation method considering irreversible decomposition of environment-friendly arc extinguishing medium and related device

Abstract

The invention belongs to the field of high-voltage environment-friendly gas circuit breakers, and discloses an arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium and a related device. Constructing a decomposition model by combining a finite rate / vortex dissipation model with a kinetic reaction rate and a turbulence-chemical behavior, and simulating a diffusion behavior of a decomposition product by using a component transport equation; the model is coupled with an arc magnetohydrodynamic unit constructed on the basis of an arc extinguish chamber structure, physical property parameters and boundary conditions, and joint solving is carried out through a finite volume method multi-physical field solver. According to the method, the decomposition behavior of the environment-friendly mixed gas under the action of the electric arc and the simulation precision of the decomposition behavior on the influence of the decomposition behavior on the electric arc characteristics are remarkably improved, and the interaction mechanism of the non-equilibrium chemical process and the electromagnetic thermal fluid multi-physical field is truly reflected; and reliable prediction of a large-current on-off dynamic process and key performance parameters is realized under acceptable computing resources.

Description

Technical Field

[0001] This invention belongs to the technical field of high-voltage environmentally friendly gas circuit breakers, and particularly relates to an arc simulation method and related device that considers the irreversible decomposition of environmentally friendly arc-extinguishing media. Background Technology

[0002] High-voltage gas circuit breakers are critical equipment for the safe and stable operation of power systems, and must effectively interrupt rated short-circuit current during circuit faults. Traditional SF6 gas has long been the mainstream choice due to its excellent insulation and arc-quenching properties; however, its extremely high global warming potential (GWP) poses a significant environmental hazard and has been subject to strict restrictions by numerous international regulations and industry standards. As power systems develop towards higher voltage and higher current levels, the research and application of environmentally friendly arc-quenching media has become an urgent industry need. Environmentally friendly gaseous media such as heptafluoroisobutyronitrile (C4F7N) serve as core alternatives to SF6, boasting high insulation strength, arc-quenching performance close to SF6, low GWP, and good thermal stability, and are widely used in circuit breakers ranging from 12kV to 252kV. In practical engineering, it is often mixed with CO2, O2, etc., to overcome the problem of low-temperature liquefaction, achieving a balance between insulation performance and vaporization characteristics. However, during the current interruption process, under the extremely complex high-temperature arc plasma and multi-field coupling environment of the arc-extinguishing chamber, the C4F7N mixed gas inevitably undergoes a chemical reaction, decomposes into a variety of products, and cannot restore the original molecular structure, resulting in changes in gas composition and thermophysical parameters, which in turn affect the arc characteristics and interruption performance. At the same time, the deposition of solid products will also exacerbate equipment wear and insulation degradation.

[0003] Existing technologies for simulating arcing in high-voltage gas circuit breakers have significant shortcomings. Most current arc magnetohydrodynamic (MHD) models, for the sake of simplification, generally ignore the gas decomposition kinetics process, relying solely on the Gibbs free energy minimization principle to calculate the chemical equilibrium composition of the gas mixture at different temperatures, and then deriving the thermodynamic properties and transport coefficients of the real gas. This simplified approach fails to accurately reflect the impact of C4F7N gas mixture decomposition on arc characteristics and breaking performance, leading to significant discrepancies between simulation results and experimental data. Furthermore, research on numerical simulation methods that couple C4F7N decomposition behavior with arc magnetohydrodynamics is insufficient. Current technologies cannot, at an acceptable computational cost, simultaneously account for the combined limitations of non-equilibrium chemical kinetics gas medium decomposition and the multi-field coupling of magnetohydrodynamics, making it difficult to accurately predict the dynamic behavior and key performance parameters of high-voltage circuit breakers during high-current breaking.

[0004] It is evident that existing technologies lack an arc simulation model that takes into account both the non-equilibrium chemical kinetic decomposition of C4F7N mixed gas and the multi-field coupling of magnetohydrodynamics, thus failing to provide a reliable basis for the structural design of the arc-extinguishing chamber of new environmentally friendly gas circuit breakers and the optimization of gas ratio. Summary of the Invention

[0005] This invention provides an arc simulation method and related device that considers the irreversible decomposition of environmentally friendly arc-extinguishing media, in order to solve the problem that the existing technology lacks an arc simulation model that takes into account the non-equilibrium chemical kinetic decomposition of C4F7N mixed gas and the multi-field coupling of magnetohydrodynamics. Using this method, a reliable basis can be provided for the structural design of the arc-extinguishing chamber of a new type of environmentally friendly gas circuit breaker and the optimization of gas ratio.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media includes: Based on the pre-acquired simulation parameters, the physical property parameters of each component, the pre-set current excitation and thermal boundary conditions, and the environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc extinguishing chamber, an arc magnetohydrodynamic numerical calculation unit is established. Based on a two-step simplified global chemical reaction mechanism, and combining kinetic reaction rate and turbulent-chemical behavior, a simulation model for the decomposition of environmentally friendly mixed gases is constructed. The two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of environmentally friendly mixed gases. The basic model of the simulation model for the decomposition of environmentally friendly mixed gases adopts a finite rate / eddy dissipation model. Construct component transport equations to simulate the diffusion process of each component after the decomposition of environmentally friendly mixed gases; A multiphysics solver based on the finite volume method was used to solve the numerical calculation unit of electric arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations to obtain simulation results.

[0007] Furthermore, before establishing the arc magnetohydrodynamic numerical calculation unit based on the pre-acquired simulation parameters, the physical property parameters of each component, the pre-set current excitation and thermal boundary conditions, and the environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc-extinguishing chamber, the following steps are also included: Obtain simulation parameters, including the initial simulation temperature and initial simulation pressure; A two-dimensional symmetrical geometric model was constructed based on the actual structure of the circuit breaker's arc-extinguishing chamber to obtain an environmentally friendly mixed gas circuit breaker model. The high-gradient region of the environmentally friendly mixed gas circuit breaker model is locally refined using unstructured meshes or block-structured meshes. The physical properties of each component were calculated based on the Chapman-Enskog theory and interpolation method. These physical properties include density, specific heat capacity, thermal conductivity, sound velocity, electrical conductivity, and viscosity.

[0008] Furthermore, in the step of constructing an environmentally friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism and combined with kinetic reaction rates, the environmentally friendly mixed gas is a C4F7N mixed gas; the specific expression of the two-step simplified global chemical reaction mechanism is as follows: Reaction 1:

[0009] Reaction 2: .

[0010] Furthermore, in the step of constructing an environmentally friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism and combined with kinetic reaction rates, the Arrhenius equation is used to express the relationship between the forward rate constant of the chemical kinetic reaction and temperature, as specifically expressed below:

[0011] In the formula, k f The forward rate constant of the chemical kinetic reaction. E a For activation energy, A Pre-exponential factor, β Temperature index R This is a universal gas constant.

[0012] Furthermore, the decomposition reaction rate in the finite rate / eddy dissipation model is controlled by both chemical kinetics and turbulent mixing, with the actual rate being the minimum of the two.

[0013] Furthermore, in the step of constructing the component transport equation for simulating the diffusion process of each component after the decomposition of environmentally friendly mixed gases, the component transport equation is specifically expressed as follows:

[0014]

[0015] In the formula, Y i , J i and R i These represent the mass fraction, diffusion flux, and net production rate of species i due to the chemical reaction, respectively. D i Where is the diffusion coefficient. μ t The turbulent viscosity coefficient, S c t is the turbulent Schmitt number, used to describe the turbulent diffusion effect.

[0016] Furthermore, the multiphysics solver based on the finite volume method is used to solve the numerical calculation unit of electric arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations, including: By setting the plunger contact and piston movement in opposite directions, the actual operating conditions of the circuit breaker's arc-extinguishing chamber are equivalently represented, and numerical calculations of the entire breaking process and simulations of the arc-burning medium decomposition process are carried out. Based on the preset initial temperature, airflow velocity, initial inflation pressure, and current input, and by performing piecewise linear fitting on the velocity and actual stroke curves of the moving parts, the dynamic mesh calculation unit in the solver ANSYS Fluent is used to discretize and solve the numerical calculation unit of the arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations to obtain the simulation results.

[0017] An arc simulation system considering the irreversible decomposition of environmentally friendly arc-extinguishing media includes: The first construction module is used to establish an arc magnetohydrodynamic numerical calculation unit based on the pre-acquired simulation parameters, the physical property parameters of each component, the pre-set current excitation and thermal boundary conditions, and the environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc extinguishing chamber. The second building module is used to construct a simulation model for the decomposition of environmentally friendly mixed gases based on a two-step simplified global chemical reaction mechanism, combined with kinetic reaction rates and turbulent-chemical behavior; wherein, the two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of environmentally friendly mixed gases; the basic model of the simulation model for the decomposition of environmentally friendly mixed gases adopts a finite rate / eddy dissipation model. The third building module is used to construct component transport equations for simulating the diffusion process of each component after the decomposition of environmentally friendly mixed gases; The solver module is used to solve the numerical calculation unit of electric arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model and the component transport equation using a multiphysics solver based on the finite volume method, so as to obtain simulation results.

[0018] An arc simulation device that takes into account the irreversible decomposition of environmentally friendly arc-extinguishing media includes: Memory, used to store computer programs; A processor is used to implement the steps of the above-described arc simulation method that considers the irreversible decomposition of environmentally friendly arc-extinguishing media when executing the computer program.

[0019] A computer-readable storage medium storing a computer program, which, when executed by a processor, is used to implement the steps of the above-described arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention provides an arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media. It employs a two-step simplified global chemical reaction mechanism to describe the decomposition kinetics of environmentally friendly mixed gases, and uses a finite rate / eddy dissipation model combined with kinetic reaction rates and turbulent-chemical behavior to construct a decomposition model. Simultaneously, it utilizes component transport equations to simulate the diffusion behavior of decomposition products. This model is coupled with an arc magnetohydrodynamic unit constructed based on the arc-extinguishing chamber structure, physical parameters, and boundary conditions, and finally solved jointly using a finite volume method multiphysics solver. This method is the first to tightly couple the non-equilibrium chemical decomposition kinetics of environmentally friendly mixed gases with the arc magnetohydrodynamic process. The simplified global reaction mechanism significantly reduces computational complexity while ensuring accurate characterization of key decomposition paths, and the introduction of component transport equations ensures accurate simulation of the spatial distribution evolution of decomposition product concentrations. This method significantly improves the simulation accuracy of the decomposition behavior of environmentally friendly mixed gases under electric arc and its impact on arc characteristics. It realistically reflects the interaction mechanism between non-equilibrium chemical processes and electromagnetic-thermal fluid multiphysics fields. Under acceptable computing resources, it achieves reliable prediction of the dynamic process of high-current interruption and key performance parameters, providing a scientific and effective simulation basis for the optimized design of the arc-extinguishing chamber of environmentally friendly gas circuit breakers and the selection of gas ratios. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of an environmentally friendly mixed gas circuit breaker model provided in an embodiment of the present invention; Figure 2 The schematic diagram of the synthesis loop experimental circuit of the decomposition model verification experimental platform provided in the embodiments of the present invention; Figure 3 A comparison chart of the stress simulation results of the decomposition simulation model provided in this embodiment of the invention and the experimental results; Figure 4 This is a qualitative analysis chart of the types and contents of post-arc decomposition products using GC-MS, provided in an embodiment of the present invention. Figure 5 The molar concentration distribution of C4F7N in the arc extinguishing chamber at different times during the arc extinguishing process is provided in this embodiment of the invention. Figure 6 A comparison of the actual reaction rate at -10 ms provided in the embodiments of the present invention; wherein, (a) is the dynamic reaction rate diagram of the arc-extinguishing chamber; and (b) is the reaction rate considering turbulent coupling; Figure 7 The graph shows the evolution of the actual decomposition rate of C4F7N over time, obtained from the arc power input and simulation calculations, as provided in this embodiment of the invention. Figure 8 A graph showing the comparison between the calculated decomposition rate provided in this embodiment of the invention and existing experimental results; Figure 9 This is a schematic diagram illustrating the implementation process of an arc simulation method considering the irreversible decomposition of an environmentally friendly arc-extinguishing medium, as provided in an embodiment of the present invention. Figure 10 A flowchart of an arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media, provided as an embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of an arc simulation system that considers the irreversible decomposition of an environmentally friendly arc-extinguishing medium, as provided in an embodiment of the present invention. Detailed Implementation

[0022] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0023] As mentioned in the background section, most existing arc MHD models, for computational simplification, largely ignore decomposition kinetics. They calculate the thermodynamic and chemical equilibrium composition of the mixed gas at different temperatures based on the Gibbs free energy minimization principle, and then calculate the thermodynamic properties and transport coefficients of the real gas. This process cannot accurately reflect the impact of the irreversible decomposition behavior of the new environmentally friendly gas medium on arc characteristics and breaking performance, leading to significant discrepancies between simulation and experiment. Therefore, it is evident that existing simulation methods, when using C4F7N as a substitute gas for SF6 in high-voltage, high-current circuit breaker applications, suffer from the problem of inaccurate simulation of the decomposition reaction effects.

[0024] To achieve the aforementioned objectives, this embodiment provides an arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media. This method introduces a two-step global chemical reaction mechanism and couples it with a turbulent mixing rate constraint model, achieving a multi-physics coupled solution of decomposition kinetics and electromagnetic fields. This method can realistically reproduce the physical characteristics of the arc and the distribution of decomposition products during the arc breaking process, overcoming the shortcomings of traditional equilibrium models that neglect decomposition kinetics, leading to large prediction errors. It provides a reliable numerical tool for arc-extinguishing chamber structure optimization, mixed gas ratio design, and operational risk assessment, and is of great significance for promoting the engineering application of environmentally friendly gas circuit breakers.

[0025] like Figure 10 As shown, this embodiment provides an arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media, including: Based on the pre-acquired simulation parameters, the physical property parameters of each component, the pre-set current excitation and thermal boundary conditions, and the environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc extinguishing chamber, an arc magnetohydrodynamic numerical calculation unit is established. Based on a two-step simplified global chemical reaction mechanism, and combining kinetic reaction rate and turbulent-chemical behavior, a simulation model for the decomposition of environmentally friendly mixed gases is constructed. The two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of environmentally friendly mixed gases. The basic model of the simulation model for the decomposition of environmentally friendly mixed gases adopts a finite rate / eddy dissipation model. Construct component transport equations to simulate the diffusion process of each component after the decomposition of environmentally friendly mixed gases; A multiphysics solver based on the finite volume method was used to solve the numerical calculation unit of electric arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations to obtain simulation results.

[0026] The prediction method provided in this embodiment will be further explained below with reference to the accompanying drawings: like Figure 9 As shown, this embodiment provides an arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media. In this embodiment, the environmentally friendly mixed gas is a C4F7N mixed gas. The specific steps of the arc simulation method are as follows: Step 1: Construct the core computational framework for multi-field coupled arc magnetohydrodynamic simulation, namely the arc magnetohydrodynamic numerical computation unit: Based on the actual structure of the circuit breaker's arc-extinguishing chamber, a two-dimensional symmetrical geometric model was established, thus constructing an environmentally friendly mixed gas circuit breaker model. This model focuses on the locations of key components such as the nozzle, compressor chamber, and contacts. Unstructured or block-structured meshes were used, with local refinement of high-gradient regions to improve the calculation accuracy of the magnetohydrodynamic (MHD) equations. A cold-hot state separation calculation method was adopted, combined with actual operating conditions, to accurately obtain the initial simulation temperature and pressure. The initial flow velocity across the entire domain was set to 0 m / s, assuming no pre-blowing or motion effects at the initial simulation moment. The physical properties of each component (specific heat capacity, thermal conductivity, viscosity, etc.) were pre-calculated in the high-temperature range using Chapman-Enskog theory and interpolation, and were retrieved in real-time during the simulation based on local temperature, pressure, and component concentration. The current excitation and thermal boundary conditions were precisely set according to actual conditions to ensure that the numerical simulation could be conducted under operating conditions highly consistent with the experiment, laying the foundation for subsequent embedded decomposition dynamics.

[0027] Step 2: Propose a two-step simplified global chemical reaction mechanism to characterize the decomposition of C4F7N: During the current interruption process, due to the piston-driven cavity compression, a large amount of cold gas is rapidly accelerated and injected into the arc region where the temperature exceeds 10000 K. Under the action of the high-temperature arc, gas molecules undergo varying degrees of dissociation into simple atoms or ions, and recombine as the gas cools after arc extinction. SF6, with its simple and symmetrical molecular structure, can largely recombine into its original form, while novel arc-extinguishing media such as C4F7N, with its complex and long-chain structure, tend not to modify its original molecules, but rather generate smaller molecular fragments. To accurately describe the irreversible decomposition of C4F7N in the high-temperature arc region under controllable complexity, this embodiment proposes the following two-step simplification of the global reaction mechanism based on experimental results from relevant studies and the principle of atomic conservation: (1) Reaction 1:

[0028] Based on relevant studies on the decomposition of C4F7N gas mixtures under arc conditions, when the content of X in the gas mixture is sufficient... O2 >9 / 4 X C 4 F 7 N When this is done, the formation of solid carbon can be effectively suppressed, and a simplified global reaction mechanism based on the conservation of product atoms can be derived as follows:

[0029] Chemical analysis of the gas produced after the electric arc revealed that under the high temperature of the arc, C4F7N first breaks CN and some CF bonds, generating CO and CF4 as the main gaseous products, accompanied by the release of N2. This process is rapid and exothermic. To effectively suppress the formation of carbon solid particles during the fragmentation process, the stoichiometric coefficient of C4F7N was set to 1, and O2 was set to 9 / 4. Based on relevant studies of decomposition products, the products were adjusted and balanced, leading to the proposed chemical reaction one.

[0030] (2) Reaction 2:

[0031] After the decomposition products are thoroughly mixed with a large amount of buffer gases (CO2, O2) in turbulent flow, CO will be further oxidized to CO2.

[0032] The classic Arrhenius equation is used to describe chemical kinetic reactions. k f The relationship between the positive rate constant and temperature is expressed as:

[0033] in E a For activation energy, A Pre-exponential factor, β Temperature indexR The rate constant is a universal gas constant. In this work, the rate of reaction one is derived by theoretical kinetics and verified by concentration changes observed from tube furnace experiments; for reaction two, the rate constant is adopted from a similar reaction in the Reaction Mechanism Generator (RMG) developed by MIT.

[0034] Step 3: Based on the two-step simplification of the global chemical reaction, and combined with the kinetic reaction rate, a finite rate / vortex dissipation model for more accurately locating the chemical reaction rate is proposed, thus obtaining the environmentally friendly mixed gas decomposition simulation model: Based on the two simplified descriptions of the chemical reactions and related reaction rates proposed in step 2, the Arrhenius equation does not consider the effects of turbulence. During arc discharge, plasma flow is dominated by turbulence, and the mixing efficiency between reactants and products depends significantly on the local turbulence scale. The thermal decomposition of C4F7N begins at around 650 °C and almost completely decomposes above 1000 °C. Given that the temperature inside the arc is much higher than these values, the chemical reaction proceeds rapidly, and the overall rate of the chemical reaction is mainly limited by the turbulent mixing efficiency.

[0035] To more accurately simulate the rate-controlled process of the C4F7N decomposition reaction, this embodiment employs a finite rate / eddy-dissipation model (FR / EDM) to limit the reaction rate to a smaller value between chemical kinetics and turbulent mixing rate. This step reliably couples the chemical decomposition kinetics at high temperatures with the turbulent-controlled mixing / dissipation process, thereby accurately reflecting the spatial distribution and transformation of the two control mechanisms—"chemically confined" and "mixing-confined"—in the arc region and nozzle flow field, while keeping computational costs under control. This ensures that the reaction is confined by turbulent mixing in regions with high chemical rates but slow mixing (high-temperature arc core), while in regions with sufficient mixing (arc edge or cold gas region), the reaction follows chemical kinetics.

[0036] Step 4: Construct component transport equations to simulate the diffusion process of each component after the decomposition of C4F7N, solve the species transport equations, and update the thermophysical parameters in real time. Based on the actual chemical reaction rate obtained in step 3, the purpose of this step is to accurately solve the spatiotemporal transport of each decomposition / reaction species at every moment and within every control volume, and to update the thermophysical properties of the mixed gas in real time, thereby ensuring the physical consistency and numerical stability of the multi-field coupling of gas flow, chemistry, electromagnetics, and temperature, wherein: (1) In order to describe the mixing and transport of all chemical components, including the polytetrafluoroethylene (PTFE) vapor generated by ablation, component transport equations are used to simulate the components. i The diffusion process is expressed as follows:

[0037]

[0038] In the formula: Y i , J i and R i These represent the mass fraction, diffusion flux, and net production rate of species i due to the chemical reaction, respectively. D i Where is the diffusion coefficient. μ t The turbulent viscosity coefficient, S c t is the turbulent Schmidt number, used to describe the turbulent diffusion effect.

[0039] (2) The localized changes in the composition of the gas mixture after chemical decomposition significantly affect physical properties such as viscosity, thermal conductivity, specific heat, density, and electrical conductivity. According to standard statistical thermodynamics and... Chapman-Enskog Transport theory calculates the thermophysical and transport properties of all species, listing these properties in the form of equations of state over the relevant ranges of pressure (0.1-10 MPa) and temperature (300-35000 K), and retrieves them in the solver by interpolation.

[0040] Step 5: Perform numerical calculations of the entire breakup process and simulate the decomposition process of the arcing medium: Based on the numerical calculation unit of electric arc magnetohydrodynamics established in step 1, the environmentally friendly mixed gas decomposition simulation model proposed in steps 2 and 3, and the species transport calculation model proposed in step 4, i.e. the component transport equation, the multiphysics solver ANSYS Fluent based on the finite volume method is used to discretize and numerically solve all the governing equations.

[0041] For example, in actual simulations, due to the complexity of realizing the actual movement of components such as nozzles, a relative motion method is used. This is achieved by setting the plunger contact and piston movement in opposite directions to represent the actual operating conditions. Considering that the mechanical speed is much lower than the speed of sound, the impact of this equivalence on the simulation results can be ignored.

[0042] The initial temperature, airflow velocity, initial inflation pressure, and current input of the model are set in the solver, and the velocity of the moving parts and the actual stroke curve are piecewise linearly fitted. The opening and closing process is simulated using dynamic mesh computing units.

[0043] The implementation of this step can accurately simulate the decomposition coupling effect of C4F7N in an electric arc environment and its impact on the characteristics of electric arc, electromagnetic field and flow field, while ensuring physical consistency and computational feasibility. This provides reliable numerical basis for circuit breaker structural design, nozzle optimization and gas ratio selection.

[0044] Step 6: Based on the breaking experiment data and the decomposition process calculations, determine the necessity of the decomposition model and the reliability of the results; To verify the effectiveness and engineering applicability of the arc simulation method that considers the irreversible decomposition of environmentally friendly arc-extinguishing media described in this embodiment, a dedicated experimental platform for circuit breaker breaking was built. The arc behavior of C4F7N mixed gas was experimentally measured and compared with the simulation results. This was used to calibrate model parameters, verify the physical reliability of numerical realization, and quantify the improvement effect of this method compared with traditional models that do not consider decomposition or chemical equilibrium.

[0045] The arc magnetohydrodynamics simulation method provided in this embodiment has been specifically applied and implemented. The specific implementation process is as follows: Based on the structure of a certain air-cooled circuit breaker, ANSYS Workbench software was used to create... Figure 1 The circuit breaker geometry model is shown and meshed. The initial temperature inside the arc-extinguishing chamber is set to 300 K, and the initial gas velocity is 0 m / s. The arc-extinguishing medium considered in the simulation is a mixture of 3.5% C4F7N-86.5% CO2-10% O2 gas, with an initial filling pressure of 0.8 MPa absolute pressure. The pressure outlet boundary is consistent with the initial filling pressure. A sinusoidal short-circuit current with an RMS value of approximately 20 kA is injected from the contact tip. The current density is subject to Neumann boundary conditions, and a Dirichlet boundary condition with zero potential is applied to the hollow contacts. The average mechanism velocity used in the numerical calculation is 7 m / s.

[0046] A dedicated experimental platform was built for the arc simulation model considering the irreversible decomposition of the environmentally friendly arc-extinguishing medium. The circuit breaker model used in the experiment was modified from a product-grade air-cooled circuit breaker, possessing the same internal structure as that used in the numerical simulation, with a maximum allowable filling pressure of 1 MPa. The arc contacts were made of CuW80 material, and the polymer nozzle was made of commonly used PTFE material with light BN doping. The movement of the components was controlled by a hydraulic operating mechanism with a total stroke of approximately 200 mm. A linear displacement sensor mounted on the moving rod of the hydraulic actuator was used to measure the real-time displacement, and the actual velocity was calculated based on the measured displacement data. A current source of the synthetic test circuit was used to simulate the high short-circuit current during actual interruption. An LC resonant circuit was used as the current source, with an oscillation frequency of 50 Hz. The experimental circuit schematic is shown below. Figure 2As shown. The output current is controlled by adjusting the charging voltage of the capacitor bank. In this study, the current is set to 25 kA. Due to the damping effect, the amplitude of the second half-cycle is slightly lower than that of the first half-cycle.

[0047] like Figure 3 As shown, for better comparison, the stress results of a traditional simulation model that does not consider decomposition effects are also presented. It can be intuitively seen that a high degree of consistency is observed in the stress curves; the simulated stress is very close to the experimental results measured at the corresponding locations in both trend and numerical value. Furthermore, compared to the traditional simulation model that does not consider decomposition effects, the simulation model proposed in this embodiment obtains more accurate prediction results.

[0048] After the experiment, the post-arc gas was collected, and the decomposition products were qualitatively analyzed using gas chromatography-mass spectrometry (GC-MS), such as... Figure 4 As shown in the figure, CO and CF4 are the main decomposition products of the C4F7N-CO2-O2 mixture, while trace amounts of C2F3N and C3F5N were also detected. These findings are largely consistent with literature reports using FTIR or other detection techniques, confirming that the proposed simplified reaction mechanism can reasonably represent the main post-arc decomposition products.

[0049] For the transient chemical processes inside the arc-extinguishing chamber that are difficult to observe during arc combustion, the arc simulation model proposed in this embodiment, which considers the irreversible decomposition of the environmentally friendly arc-extinguishing medium, can accurately characterize them and provide an effective approach for studying the irreversible decomposition process of C4F7N and the spatiotemporal evolution of chemical species. Figure 5 The molar concentration distribution of the key species C4F7N in the arc extinguishing chamber at different times during the interruption process is shown. In the initial stage of the arc (-10 ms), C4F7N undergoes rapid thermal decomposition in the high-temperature arc, leading to a significant decrease in its concentration in the arc core region. As the compressor chamber compresses and blows the fresh C4F7N mixture into the arc region, the decomposition products diffuse downstream into the cooling volume driven by the airflow. As the current increases, near the peak value at -5 ms, the arc-induced blocking effect forces the high-temperature gas into the compressor chamber, at which point further decomposition of C4F7N can be observed, primarily along the connecting channel.

[0050] According to the finite rate / eddy dissipation model (FR / EDM) proposed in this embodiment, the decomposition reaction rate is jointly controlled by chemical kinetics and turbulent mixing, and the actual rate is the minimum of the two. Figure 6 A comparison of the kinetic reaction rate and the actual reaction rate at -10 ms. Specifically, as follows... Figure 6As shown in (a) and (b), a comparison clearly reveals that the kinetic rate is concentrated in the high-temperature arc core, while the actual reaction rate is limited by turbulent mixing, with the decomposition reaction mainly occurring at the arc edge. In the arc core, due to the extremely high temperature, C4F7N decomposes almost instantaneously, and the depletion of fresh C4F7N prevents sustained reaction. Therefore, the kinetic rate calculation method significantly overestimates the actual reaction rate. Considering the effects of turbulence, fresh C4F7N can be transported to the outer regions of the arc; if the reaction is modeled solely based on chemical kinetics, the amount of C4F7N consumed will be overestimated. Therefore, the limitation of the reaction rate by turbulence is crucial for simulating the decomposition process.

[0051] Figure 7 The time evolution of the arc power input and the calculated actual decomposition rate of C4F7N are presented. It was observed that the decomposition rate of C4F7N varies with the arc power, with a significant difference observed in the high-current phase of the second half-cycle. Figure 8 The calculated decomposition rate was compared with existing experimental results. The decomposition rate of C4F7N under arc conditions is affected by various factors such as arc current, arcing time, and arc-extinguishing chamber design. Relevant data show that the decomposition rate generally exhibits a linear relationship with the current. Based on these data, linear fitting indicates that the decomposition rate at 20 kA is approximately 0.139 mol / MJ, while the decomposition rate obtained in this simulation is approximately 0.120 mol / MJ, which agrees well with the predicted trend, further verifying the accuracy of the FR / EDM-based C4F7N decomposition model developed in this embodiment.

[0052] Therefore, this embodiment provides an arc simulation method that considers the irreversible decomposition of the environmentally friendly arc-extinguishing medium. This method can solve the problem of large pressure prediction deviations caused by neglecting decomposition kinetics and turbulent mixing effects in traditional models. First, a multi-physics-based arc magnetohydrodynamic (MHD) framework is constructed, and the initial simulation conditions and boundary constraints are set. Second, a two-step global chemical reaction mechanism is constructed to simulate the complex non-equilibrium chemical reaction process inside the arc-extinguishing chamber under the action of a high-temperature arc. Subsequently, a finite rate / eddy dissipation (FR / EDM) model is introduced to calculate the limited chemical reaction rate, solve the species transport equation, and update the physical properties of the gas medium in real time. Finally, numerical calculations of the breaking process are performed based on the finite volume method. Data such as transient pressure, arc voltage, and decomposition product distribution are obtained experimentally and compared with the simulation results. The high consistency between the experimental results and the simulation model calculation results confirms the accuracy and reliability of this arc simulation model.

[0053] like Figure 11 As shown, this embodiment also provides an arc simulation system that considers the irreversible decomposition of environmentally friendly arc-extinguishing media, including: The first construction module is used to establish an arc magnetohydrodynamic numerical calculation unit based on pre-acquired simulation parameters, physical property parameters of each component, pre-set current excitation and thermal boundary conditions, and an environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc-extinguishing chamber. The second construction module is used to construct an environmentally friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism, combined with kinetic reaction rate and turbulent-chemical behavior. The two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of the environmentally friendly mixed gas. The basic model of the environmentally friendly mixed gas decomposition simulation model adopts a finite rate / eddy dissipation model. The third construction module is used to construct component transport equations to simulate the diffusion process of each component after the decomposition of the environmentally friendly mixed gas. The solution module is used to solve the arc magnetohydrodynamic numerical calculation unit, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations using a multiphysics solver based on the finite volume method to obtain simulation results.

[0054] The present invention also provides an arc simulation device that takes into account the irreversible decomposition of environmentally friendly arc extinguishing media, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the arc simulation method that takes into account the irreversible decomposition of environmentally friendly arc extinguishing media.

[0055] The present invention also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media.

[0056] When the processor executes the computer program, it implements the above-mentioned steps for arc simulation considering the irreversible decomposition of the environmentally friendly arc-extinguishing medium. For example, based on pre-acquired simulation parameters, physical property parameters of each component, pre-set current excitation and thermal boundary conditions, and an environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc-extinguishing chamber, an arc magnetohydrodynamic numerical calculation unit is established; based on a two-step simplified global chemical reaction mechanism, combined with kinetic reaction rate and turbulent-chemical behavior, an environmentally friendly mixed gas decomposition simulation model is constructed; wherein, the two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of the environmentally friendly mixed gas; the basic model of the environmentally friendly mixed gas decomposition simulation model adopts a finite rate / eddy dissipation model; a component transport equation is constructed to simulate the diffusion process of each component after the decomposition of the environmentally friendly mixed gas; a multiphysics solver based on the finite volume method is used to solve the arc magnetohydrodynamic numerical calculation unit, the environmentally friendly mixed gas decomposition simulation model, and the component transport equation to obtain simulation results.

[0057] For example, the computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing preset functions, wherein the instruction segments describe the execution process of the computer program in the arc simulation device considering the irreversible decomposition of environmentally friendly arc-extinguishing media. For example, the computer program can be divided into a first building module, a second building module, a third building module, and a solution module. The first building module is used to establish an arc magnetohydrodynamic numerical calculation unit based on pre-acquired simulation parameters, physical property parameters of each component, pre-set current excitation and thermal boundary conditions, and an environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc-extinguishing chamber. The second building module is used to construct an environmentally friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism, combined with kinetic reaction rate and turbulent-chemical behavior. The two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of the environmentally friendly mixed gas. The basic model of the environmentally friendly mixed gas decomposition simulation model adopts a finite rate / eddy dissipation model. The third building module is used to construct component transport equations for simulating the diffusion process of each component after the decomposition of the environmentally friendly mixed gas. The solution module is used to solve the arc magnetohydrodynamic numerical calculation unit, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations using a multiphysics solver based on the finite volume method to obtain simulation results.

[0058] The arc simulation device considering the irreversible decomposition of environmentally friendly arc-extinguishing media can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. This device may include, but is not limited to, processors and memory. Those skilled in the art will understand that the above are examples of arc simulation devices considering the irreversible decomposition of environmentally friendly arc-extinguishing media and do not constitute a limitation on such devices. The device may include more components than described above, or combine certain components, or use different components. For example, the arc simulation device considering the irreversible decomposition of environmentally friendly arc-extinguishing media may also include input / output devices, network access devices, buses, etc.

[0059] The processor referred to can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or any conventional processor. The processor is the control center of the arc simulation considering the irreversible decomposition of environmentally friendly arc-extinguishing media, and connects all parts of the arc simulation equipment using various interfaces and lines.

[0060] The memory can be used to store the computer program and / or modules. The processor realizes various functions of the arc simulation device that takes into account the irreversible decomposition of the environmentally friendly arc extinguishing medium by running or executing the computer program and / or modules stored in the memory and calling the data stored in the memory.

[0061] The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function (such as sound playback, image playback, etc.). The data storage area may store data created based on the use of the mobile phone (such as audio data, phonebook, etc.). Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital cards (SD cards), flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0062] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the described arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media.

[0063] If the modules / units of the arc simulation system that considers the irreversible decomposition of environmentally friendly arc extinguishing media are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0064] Based on this understanding, the present invention can implement all or part of the processes in the above-mentioned arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media. This can also be accomplished by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the above-mentioned arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or a preset intermediate form, etc.

[0065] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0066] It should be noted that the content contained in the computer-readable storage medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0067] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. An arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media, characterized in that, include: Based on the pre-acquired simulation parameters, the physical property parameters of each component, the pre-set current excitation and thermal boundary conditions, and the environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc extinguishing chamber, an arc magnetohydrodynamic numerical calculation unit is established. Based on a two-step simplified global chemical reaction mechanism, and combining kinetic reaction rate and turbulent-chemical behavior, a simulation model for the decomposition of environmentally friendly mixed gases is constructed. The two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of environmentally friendly mixed gases. The basic model of the simulation model for the decomposition of environmentally friendly mixed gases adopts a finite rate / eddy dissipation model. Construct component transport equations to simulate the diffusion process of each component after the decomposition of environmentally friendly mixed gases; A multiphysics solver based on the finite volume method was used to solve the numerical calculation unit of electric arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations to obtain simulation results.

2. The arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media according to claim 1, characterized in that, Before establishing the arc magnetohydrodynamic numerical calculation unit based on the pre-acquired simulation parameters, the physical property parameters of each component, the pre-set current excitation and thermal boundary conditions, and the environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc-extinguishing chamber, the following is also included: Obtain simulation parameters, including the initial simulation temperature and initial simulation pressure; A two-dimensional symmetrical geometric model was constructed based on the actual structure of the circuit breaker's arc-extinguishing chamber to obtain an environmentally friendly mixed gas circuit breaker model. The high-gradient region of the environmentally friendly mixed gas circuit breaker model is locally refined using unstructured meshes or block-structured meshes. The physical properties of each component were calculated based on the Chapman-Enskog theory and interpolation method. These physical properties include density, specific heat capacity, thermal conductivity, sound velocity, electrical conductivity, and viscosity.

3. The arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media according to claim 1, characterized in that, In the step of constructing an environmentally friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism and combined with kinetic reaction rates, the environmentally friendly mixed gas is a C4F7N mixed gas; the specific expression of the two-step simplified global chemical reaction mechanism is as follows: Reaction 1: Reaction 2: .

4. The arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media according to claim 3, characterized in that, In the step of constructing an environmentally friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism and combined with kinetic reaction rates, the Arrhenius equation is used to express the relationship between the forward rate constant of the chemical kinetic reaction and temperature, as specifically expressed below: In the formula, k f The forward rate constant of the chemical kinetic reaction is... E a For activation energy, A Pre-exponential factor, β Temperature index R This is a universal gas constant.

5. The arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media according to claim 1, characterized in that, The decomposition reaction rate in the finite rate / eddy dissipation model is controlled by both chemical kinetics and turbulent mixing, with the actual rate being the minimum of the two.

6. The arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media according to claim 1, characterized in that, In the step of constructing component transport equations for simulating the diffusion process of each component after the decomposition of environmentally friendly mixed gases, the component transport equations are specifically expressed as follows: In the formula, Y i , J i and R i These represent the mass fraction, diffusion flux, and net production rate of species i due to the chemical reaction, respectively. D i The diffusion coefficient is... μ t The turbulent viscosity coefficient, S c t is the turbulent Schmitt number, used to describe the turbulent diffusion effect.

7. The arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media according to claim 1, characterized in that, The multiphysics solver based on the finite volume method is used to solve the numerical calculation unit of electric arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations, including: By setting the plunger contact and piston movement in opposite directions, the actual operating conditions of the circuit breaker's arc-extinguishing chamber are equivalently represented, and numerical calculations of the entire breaking process and simulations of the arc-burning medium decomposition process are carried out. Based on the preset initial temperature, airflow velocity, initial inflation pressure, and current input, and by performing piecewise linear fitting on the velocity and actual stroke curves of the moving parts, the dynamic mesh calculation unit in the solver ANSYS Fluent is used to discretize and solve the numerical calculation unit of the arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model, and the component transport equations to obtain the simulation results.

8. An arc simulation system considering the irreversible decomposition of environmentally friendly arc-extinguishing media, characterized in that, include: The first construction module is used to establish an arc magnetohydrodynamic numerical calculation unit based on the pre-acquired simulation parameters, the physical property parameters of each component, the pre-set current excitation and thermal boundary conditions, and the environmentally friendly mixed gas circuit breaker model constructed according to the actual structure of the circuit breaker arc extinguishing chamber. The second building module is used to construct a simulation model for the decomposition of environmentally friendly mixed gases based on a two-step simplified global chemical reaction mechanism, combined with kinetic reaction rates and turbulent-chemical behavior; wherein, the two-step simplified global chemical reaction mechanism is used to characterize the decomposition process of environmentally friendly mixed gases; the basic model of the simulation model for the decomposition of environmentally friendly mixed gases adopts a finite rate / eddy dissipation model. The third building module is used to construct component transport equations for simulating the diffusion process of each component after the decomposition of environmentally friendly mixed gases; The solver module is used to solve the numerical calculation unit of electric arc magnetohydrodynamics, the environmentally friendly mixed gas decomposition simulation model and the component transport equation using a multiphysics solver based on the finite volume method, so as to obtain simulation results.

9. An arc simulation device considering the irreversible decomposition of environmentally friendly arc-extinguishing media, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the arc simulation method of any one of claims 1-7, which considers the irreversible decomposition of environmentally friendly arc-extinguishing media.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the steps of the arc simulation method considering the irreversible decomposition of environmentally friendly arc-extinguishing media as described in any one of claims 1-7.

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