CN-122021141-A - Arc simulation method considering irreversible decomposition of environment-friendly arc extinguishing medium and related device

CN122021141ACN 122021141 ACN122021141 ACN 122021141ACN-122021141-A

Abstract

The invention belongs to the field of high-voltage environment-friendly gas circuit breakers, and discloses an arc simulation method and a related device considering irreversible decomposition of an environment-friendly arc extinguishing medium, wherein a two-step simplified global chemical reaction mechanism is adopted to describe the decomposition dynamic process of environment-friendly mixed gas, a finite rate/vortex dissipation model is adopted to combine the dynamic reaction rate with turbulent flow-chemical behavior to construct a decomposition model, and a component transport equation is utilized to simulate the diffusion behavior of decomposition products; the model is coupled with an arc magnetohydrodynamic unit constructed based on an arc extinguishing chamber structure, physical parameters and boundary conditions, and is subjected to joint solution through a finite-volume method multi-physical-field solver. The method remarkably improves the decomposition behavior of the environment-friendly mixed gas under the action of the electric arc and the simulation precision of the influence of the environment-friendly mixed gas on the electric arc characteristic, truly reflects the interaction mechanism of the unbalanced chemical process and the electromagnetic thermal fluid multi-physical field, and realizes the reliable prediction of the heavy current break dynamic process and key performance parameters under acceptable computing resources.

Inventors

ZHANG BOYA
Cao Minchuan
LI XINGWEN
LI BOCHEN
DENG JUNWEI
WANG GUANYU
CHEN YIMING

Assignees

西安交通大学

Dates

Publication Date: 20260512
Application Date: 20260119

Claims (10)

1. An arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium is characterized by comprising the following steps: Establishing an arc magnetohydrodynamic numerical calculation unit based on pre-acquired simulation parameters, physical parameters of each component, preset current excitation and thermal boundary conditions and an environment-friendly mixed gas circuit breaker model constructed according to the actual structure of an arc extinguishing chamber of the circuit breaker; The method comprises the steps of constructing an environment-friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism by combining dynamic reaction rate and turbulence-chemical behavior, wherein the two-step simplified global chemical reaction mechanism is used for representing the decomposition process of the environment-friendly mixed gas; constructing a component transportation equation for simulating the diffusion process of each component after the decomposition of the environment-friendly mixed gas; and solving an arc magnetohydrodynamic numerical calculation unit, an environment-friendly mixed gas decomposition simulation model and a component transportation equation by adopting a multi-physical field solver based on a finite volume method to obtain a simulation result.
2. The arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium according to claim 1, wherein before the arc magnetohydrodynamic numerical calculation unit is established based on the pre-acquired simulation parameters, physical parameters of each component, preset current excitation and thermal boundary conditions, and an environment-friendly mixed gas circuit breaker model constructed according to an actual structure of an arc extinguishing chamber of the circuit breaker, the method further comprises: obtaining simulation parameters, wherein the simulation parameters comprise a simulation initial temperature and a simulation initial pressure; constructing a two-dimensional symmetrical geometric model according to the actual structure of the arc extinguishing chamber of the circuit breaker so as to obtain an environment-friendly mixed gas circuit breaker model; local encryption is carried out on a high gradient area of the environment-friendly mixed gas circuit breaker model by adopting unstructured grids or blocked structured grids; And calculating physical parameters of each component based on the Chapman-Enskog theory and interpolation method, wherein the physical parameters comprise density, specific heat capacity, heat conductivity, sound velocity, electric conductivity and viscosity.
3. The arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium according to claim 1, wherein in the step of constructing an environment-friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism and a dynamic reaction rate, the environment-friendly mixed gas is C 4 F 7 N mixed gas, and the two-step simplified global chemical reaction mechanism is specifically expressed as follows: Reaction one: Reaction II: 。
4. The arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium according to claim 3, wherein in the step of constructing an environment-friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism and a dynamic reaction rate, the change relation of a forward rate constant of a chemical dynamic reaction with temperature is expressed by adopting an Arrhenius equation, and the method is specifically expressed as follows: Wherein k f is a forward rate constant of a chemical kinetic reaction, E a is activation energy, A is a pre-finger factor, beta is a temperature index, and R is a universal gas constant.
5. The arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium according to claim 1, wherein the decomposition reaction rate of the finite rate/vortex dissipation model is controlled based on chemical kinetics and turbulent mixing together, and the actual rate takes the minimum value of the two.
6. The arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium according to claim 1, wherein in the step of constructing a component transportation equation for simulating a component diffusion process after decomposition of an environment-friendly mixed gas, the component transportation equation is specifically expressed as follows: Wherein Y i 、J i and R i respectively represent mass fraction, diffusion flux and net generation rate of species i due to chemical reaction, D i is diffusion coefficient, μ t is turbulence viscosity coefficient, S c t is turbulence Schmitt number, and the turbulence diffusion effect is described.
7. The arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium according to claim 1, wherein the solving of the arc magnetohydrodynamic numerical calculation unit, the environment-friendly mixed gas decomposition simulation model and the component transportation equation by adopting the multi-physical-field solver based on the finite-volume method comprises the following steps: The method is characterized in that the actual operation condition of the arc extinguishing chamber of the circuit breaker is equivalently represented by arranging a mode that plunger contact is opposite to the movement direction of a piston, and the numerical calculation of the whole breaking process and the simulation of the burning medium decomposition process are started; According to preset initial temperature, air flow speed, initial inflation pressure and current input, piecewise linear fitting is carried out on the speed of a moving part and an actual travel curve, a dynamic grid computing unit in a solver ANSYS Fluent is adopted to carry out dispersion and solving on an arc magnetohydrodynamic numerical value computing unit, an environment-friendly mixed gas decomposition simulation model and a component transportation equation, and a simulation result is obtained through calculation.
8. An arc simulation system that considers irreversible decomposition of an environmentally friendly arc extinguishing medium, comprising: The first construction module is used for constructing an arc magnetohydrodynamic numerical calculation unit based on pre-acquired simulation parameters, physical parameters of each component, preset current excitation and thermal boundary conditions and an environment-friendly mixed gas circuit breaker model constructed according to the actual structure of the arc extinguishing chamber of the circuit breaker; The system comprises a first construction module, a second construction module and a third construction module, wherein the first construction module is used for constructing an environment-friendly mixed gas decomposition simulation model based on a two-step simplified global chemical reaction mechanism and combining dynamic reaction rate and turbulence-chemical behavior, and the two-step simplified global chemical reaction mechanism is used for representing the decomposition process of the environment-friendly mixed gas; the third construction module is used for constructing a component transportation equation for simulating the diffusion process of each component after the decomposition of the environment-friendly mixed gas; The solving module is used for solving the arc magnetohydrodynamic numerical calculation unit, the environment-friendly mixed gas decomposition simulation model and the component transportation equation by adopting a multi-physical field solver based on a finite volume method so as to obtain a simulation result.
9. An arc simulation apparatus that considers irreversible decomposition of an environmentally friendly arc extinguishing medium, comprising: A memory for storing a computer program; a processor for implementing the steps of the arc simulation method of any one of claims 1-7, when executing said computer program, taking into account the irreversible decomposition of an environmentally friendly arc extinguishing medium.
10. A computer readable storage medium storing a computer program, characterized in that the computer program is executed by a processor for implementing the steps of the arc simulation method according to any one of claims 1-7 taking into account the irreversible decomposition of an environmentally friendly arc extinguishing medium.

Description

Arc simulation method considering irreversible decomposition of environment-friendly arc extinguishing medium and related device Technical Field The invention belongs to the technical field of high-voltage environment-friendly gas circuit breakers, and particularly relates to an arc simulation method and a related device considering irreversible decomposition of an environment-friendly arc extinguishing medium. Background The high-voltage gas circuit breaker is used as key equipment for safe and stable operation of a power system, and rated short-circuit current needs to be effectively interrupted when a circuit fails. Conventional SF 6 gas has been a long-standing mainstream for excellent insulation and arc extinguishing properties, but has been severely limited by various international regulations and industry standards due to its extremely high Global Warming Potential (GWP) which is a significant environmental hazard. Along with the development of a power system to higher voltage and higher current levels, the development and application of environment-friendly arc extinguishing media become urgent demands of the industry. The environment-friendly gas medium such as heptafluoroisobutyronitrile (C 4F7 N) is used as a core alternative scheme of SF 6, is widely applied to 12 kV-252 kV-class circuit breakers by virtue of high insulation strength, arc extinguishing performance close to SF 6, low GWP and good thermal stability, and is often mixed with CO 2、O2 and the like in actual engineering to overcome the problem of low-temperature liquefaction, so that the insulation performance and gasification characteristics are both realized. However, in the current breaking process, under the extremely complex high-temperature arc plasma and multi-field coupling environment of the arc extinguishing chamber, the C 4F7 N mixed gas inevitably undergoes chemical reaction, is decomposed to generate various products, and cannot recover the original molecular structure, so that the gas composition is changed, the thermophysical parameters are changed, the arc characteristics and breaking performance are further affected, and meanwhile, the equipment abrasion and insulation degradation are further aggravated by the deposition of solid products. The related technology of arc simulation of the existing high-voltage gas circuit breaker has obvious defects. Most of current arc Magnetohydrodynamic (MHD) models are used for simplifying calculation, the gas decomposition dynamic process is generally ignored, the chemical equilibrium composition of the mixed gas at different temperatures is calculated based on the Gibbs free energy minimization principle only, and the thermodynamic property and the transport coefficient of the real gas are deduced according to the chemical equilibrium composition. Meanwhile, the numerical simulation method for coupling the C 4F7 N decomposition behavior and arc magnetohydrodynamic is not fully researched, and the prior art cannot consider the comprehensive limitation of unbalanced chemical dynamic gas medium decomposition and magnetohydrodynamic multi-field coupling under acceptable calculation cost, so that the dynamic behavior and key performance parameters of the high-current switching process of the high-voltage circuit breaker are difficult to truly predict. Therefore, the prior art lacks an arc simulation model which takes into account both unbalanced chemical kinetic decomposition and magnetohydrodynamic multi-field coupling of the C 4F7 N mixed gas, and cannot provide reliable basis for structural design and gas proportion optimization of the novel environment-friendly gas circuit breaker arc extinguishing chamber. Disclosure of Invention The invention provides an arc simulation method and a related device considering irreversible decomposition of an environment-friendly arc extinguishing medium, which are used for solving the problem that the prior art lacks an arc simulation model considering unbalanced chemical kinetic decomposition and magnetohydrodynamic multi-field coupling of C 4F7 N mixed gas, and can provide reliable basis for structural design and gas proportion optimization of a novel environment-friendly gas circuit breaker arc extinguishing chamber. In order to achieve the above purpose, the invention adopts the following technical scheme: an arc simulation method considering irreversible decomposition of an environment-friendly arc extinguishing medium, comprising: Establishing an arc magnetohydrodynamic numerical calculation unit based on pre-acquired simulation parameters, physical parameters of each component, preset current excitation and thermal boundary conditions and an environment-friendly mixed gas circuit breaker model constructed according to the actual structure of an arc extinguishing chamber of the circuit breaker; The method comprises the steps of constructing an environment-friendly mixed gas decomposition simulation model based on a two-step simplified global