Method and device for predicting physical property parameters of arc plasma

Abstract

The invention provides an arc plasma physical property parameter prediction method and device, and belongs to the technical field of magnetohydrodynamic simulation, and the method comprises the steps: obtaining an arc quenching medium containing polytetrafluoroethylene; obtaining particle components of arc plasma of the arc extinguishing medium; according to the particle components of the arc plasma of the arc quenching medium, thermodynamic parameters of the arc plasma are calculated, the transport coefficient of the arc plasma is calculated, and the thermodynamic parameters and the transport coefficient are physical property parameters of the arc plasma. Compared with a traditional calculation method, the method has the advantages that the influence of nozzle material ablation on the arc extinguishing medium is considered, the calculation result better meets the actual requirement, and therefore the calculation precision of the thermodynamic parameters and the transport coefficient is higher.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetohydrodynamic simulation, and particularly relates to a method and device for predicting physical property parameters of arc plasma. Background Technique

[0002] During the opening process of a circuit breaker, the ablation effect of the arc on the nozzle during the arcing stage will affect the arc quenching performance of the circuit breaker. Currently, most of the nozzle materials of self - energized circuit breakers are made of polytetrafluoroethylene. When an arc is generated during the opening process of the circuit breaker, heat transfer occurs on the wall surface. Especially the strong radiation of the arc causes the ablation of the polytetrafluoroethylene nozzle, and the generated C2F4 vapor mixes into the arc quenching medium, increasing the pressure in the cavity, thereby significantly improving the arc quenching performance of the circuit breaker.

[0003] Numerical simulation of the plasma flow and heat transfer process can effectively evaluate the insulation and arc quenching capabilities of the mixed gas. The accuracy of the simulation results depends to a large extent on the accuracy of the thermodynamic and transport properties adopted. However, data on the thermodynamic properties and transport coefficients of high - temperature C2F4 mixtures have not been reported in the literature, which is of great significance for studying the mixing of C2F4 mixed - gas arcs and ablated polytetrafluoroethylene vapor and optimizing the design of circuit breakers. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present application proposes a method and device for predicting physical property parameters of arc plasma.

[0005] In a first aspect, the present application proposes a method for predicting physical property parameters of arc plasma, including:

[0006] Obtain an arc quenching medium containing polytetrafluoroethylene;

[0007] Under different pressures and different temperature conditions in a variable - electric - field environment, obtain the particle components of the arc plasma of the arc quenching medium;

[0008] Calculate the thermodynamic parameters of the arc plasma according to the particle components of the arc plasma of the arc quenching medium;

[0009] Calculate the transport coefficients of the arc plasma, and the thermodynamic parameters and transport coefficients are the physical property parameters of the arc plasma.

[0010] The thermodynamic parameters include: the mass density of the arc plasma, the specific enthalpy of the arc plasma, and the specific heat at constant pressure of the arc plasma.

[0011] The calculation formula for the mass density of the arc plasma is as follows:

[0012]

[0013] where ρ is the mass density of the arc plasma, m i is the mass of particle i, n i is the number density of the i-th kind of particle, i.e., the particle composition of the arc plasma of the arc quenching medium, and w is the total number of particle species.

[0014] The specific enthalpy of the arc plasma is calculated as follows:

[0015]

[0016] where h is the enthalpy of a unit mass of substance, called specific enthalpy, x i is the mole fraction of particle i, is the standard enthalpy of formation, M is the molar mass of the plasma, and w is the total number of particle species.

[0017] The specific heat at constant pressure of the arc plasma is calculated as follows:

[0018]

[0019] where C p is the change value of the specific thermodynamic energy when the temperature of a unit mass of substance increases by 1 K under constant pressure conditions, called specific heat at constant pressure, h is the enthalpy of a unit mass of substance, and T is the temperature of the arc plasma.

[0020] The transport coefficients include: the electrical conductivity of the arc plasma, the thermal conductivity of the arc plasma, and the viscosity coefficient of the arc plasma.

[0021] The electrical conductivity of the arc plasma is calculated as follows:

[0022]

[0023] where σ elec is the electrical conductivity of the arc plasma, n1 is the electron number density, m1 is the electron mass, k B is the Boltzmann constant, T is the temperature of the arc plasma, m i is the mass of particle i; m j is the mass of particle j. q 00 ~q 22 are the coefficients related to the interaction between electrons and heavy particles in the plasma: q 00 is the coefficient related to the (1,1)-order collision integral Q (1,1) is the coefficient related to the (1,1)~(1,2)-order collision integrals Q 01 (1,1) (1,2) 、Q 11 is the coefficient related to the (1,1)~(2,2)-order collision integrals Q (1,1) (2,2) ~Q (2,2) ​The coefficient, q 02 is for the collision integrals Q of orders (1,1) to (1,3) (1,1) ~Q (1,3) The coefficient, q 12 is for the collision integrals Q of orders (1,1) to (2,3) (1,1) ~Q (2,3) The coefficient, q 22 is for the collision integrals Q of orders (1,1) to (2,4) (1,1) ~Q (2,4) The coefficient; is the collision integral of orders l, s for the interaction between particles i and j. If it is the collision integral of electrons, there is no i, j is the collision cross-section of order l for the interaction between particles i and j; γ ij is the initial velocity at the initialization of the interaction between particles i and j, μ ij is the reduced mass of the interaction between particles i and j; g ij is the relative initial velocity of the interaction between particles i and j, and x is the refraction angle of the colliding particles relative to the center of the gravity coordinate system; is the interaction potential between particle collisions; b is the impact parameter, r m is a characteristic distance related to the interaction between particles in the plasma; r is the distance between particles, g ij is the relative velocity of particle i and particle j.

[0024] The thermal conductivity of the arc plasma includes: electron thermal conductivity, heavy particle thermal conductivity, internal thermal conductivity, and reaction thermal conductivity. The calculation formula is as follows:

[0025] λ total =λ e +λ H +λ int +λ react

[0026] Among them, λ total is the thermal conductivity of the arc plasma, λ e is the electron thermal conductivity, λ H is the heavy particle thermal conductivity, λ int is the internal thermal conductivity, λ react is the reaction thermal conductivity.

[0027] The calculation formula for the electron thermal conductivity is as follows:

[0028]

[0029] Among them, λ e is the electron thermal conductivity, k Bis the Boltzmann constant, R is the ideal gas constant, T is the temperature of the arc plasma, n1 is the electron number density, M1 is the electron mass, q 00 ~q 22 is the coefficient related to the interaction between particles in the plasma.

[0030] The heavy particle thermal conductivity is calculated as follows:

[0031]

[0032] where λ H is the heavy particle thermal conductivity, k ii is the translational thermal conductivity of the ii system, k ij is the translational thermal conductivity of the ij system, L vv is the element in the v-th row and v-th column of the matrix λ H in which L ii is the coefficient related to the particle species, L ij is a physical quantity used to measure the influence of the interaction between different particle species i and j on the thermal conductivity; M i is the molar mass of particle i, M k is the molar mass of particle k, M j is the molar mass of particle j; is the coefficient describing the interaction characteristics between the i-th particle and the k-th particle in the arc plasma, is the coefficient describing the interaction characteristics between the i-th particle and the k-th particle in the arc plasma, is the coefficient describing the interaction characteristics between the i-th particle and the j-th particle in the arc plasma; x i is the mole fraction of particle i, x j is the mole fraction of particle j, v is the total number of particle species in the arc plasma, x v is the mole fraction of particle v.

[0033] The internal thermal conductivity is calculated as follows:

[0034]

[0035] where λ int is the internal thermal conductivity, λ int i is the internal thermal conductivity of particle i, D ij is the binary diffusion coefficient of particle ij, D ij (l) is the first-order estimate of the binary diffusion coefficient between particles kl, P is the pressure of the arc plasma, D ii (l) is the coefficient related to the diffusion characteristics of the same species of particles in the arc plasma, N a is the Avogadro constant, is the collision integral of particles, N is the total number of particle species, M i is the molar mass of particle i, M j is the molar mass of particle j, k B is the Boltzmann constant, and T is the temperature of the arc plasma.

[0036] The reaction thermal conductivity is calculated as follows:

[0037]

[0038] where λ react is the reaction thermal conductivity, ΔH μ is the enthalpy change of reaction μ, T is the temperature of the arc plasma, a ik is the stoichiometric coefficient of the k-th particle in the i-th chemical reaction, R is the ideal gas constant; P is the pressure of the arc plasma, A ij is the interaction coefficient between the i-th and j-th particles in the arc plasma, A μμ is the self-interaction coefficient of the μ-th particle, D kl (l) is the diffusion coefficient of the particles, a il is the stoichiometric coefficient of the i-th particle in the l-th chemical reaction, a jk is the stoichiometric coefficient of the j-th particle in the k-th chemical reaction, a jl is the stoichiometric coefficient of the j-th particle in the l-th chemical reaction; x k is the mole fraction of the k particles, x l is the mole fraction of the l particles, and v is the total number of particle species in the arc plasma.

[0039] The viscosity coefficient of the arc plasma is calculated as follows:

[0040]

[0041]

[0042] where η is the viscosity coefficient of the arc plasma, η ij is the viscosity of the system composed of particles ij, η ik is the viscosity of the system composed of particles ik; x i is the mole fraction of particle i, x k is the mole fraction of particle k, x v is the mole fraction of particle v, M i is the molar mass of particle i, M j is the molar mass of particle j, M kis the molar mass of particle k, v is the number of heavy particle species other than electrons, l is the number of element species, v is the total number of particle species in the arc plasma, H vv is the self - interaction coefficient of the v - th particle, H 1v is the interaction coefficient between the 1 - st particle and the v - th particle, H v1 is the interaction coefficient between the v - th particle and the 1 - st particle.

[0043] In a second aspect, the present application proposes an apparatus for predicting physical property parameters of arc plasma, including:

[0044] A dielectric acquisition module for acquiring an arc - extinguishing dielectric containing polytetrafluoroethylene;

[0045] A particle composition acquisition module for acquiring the particle composition of the arc plasma of the arc - extinguishing dielectric under different pressures and different temperature conditions in a variable - electric - field environment;

[0046] A parameter calculation module for calculating the thermodynamic parameters of the arc plasma according to the particle composition of the arc plasma of the arc - extinguishing dielectric;

[0047] A coefficient calculation module for calculating the transport coefficients of the arc plasma, and the thermodynamic parameters and transport coefficients are the physical property parameters of the arc plasma.

[0048] In a third aspect, the present application proposes an electronic device, including: one or more processors, and a memory, where the memory is used to store instructions, and when the instructions are executed by the one or more processors, the one or more processors execute the method for predicting physical property parameters of arc plasma as described above.

[0049] In a fourth aspect, the present application proposes a computer - readable storage medium storing executable instructions, and when the instructions are executed, a processor executes the method for predicting physical property parameters of arc plasma as described above.

[0050] In a fifth aspect, the present application proposes a computer program product, including a computer program or instructions, and when the computer program or instructions are executed by a processor, the method for predicting physical property parameters of arc plasma as described above is implemented.

[0051] Advantageous effects:

[0052] This application proposes a method and device for predicting the physical properties of arc plasma. Based on the remarkable feature that during the arc interruption process of a self - energy circuit breaker, the nozzle material ablation generates polytetrafluoroethylene vapor, which mixes into the arc - extinguishing medium and affects the arc - extinguishing performance of the medium, the traditional mathematical model for calculating physical properties is optimized. The calculation methods for the thermodynamic parameters and transport coefficients of the arc plasma during the nozzle ablation in the arc interruption of the self - energy circuit breaker are summarized, and the physical property parameter data can be accurately obtained. By obtaining the physical property parameters of the gas arc under different conditions, researchers can better simulate and analyze the behavior of the arc in magnetohydrodynamic simulation calculations to guide the design and optimization process. Compared with the traditional calculation method, the method of this application considers the influence of nozzle material ablation on the arc - extinguishing medium when calculating the physical properties of the arc plasma during the opening process of the self - energy circuit breaker, and the calculation results are more in line with the actual requirements, thus making the calculation accuracy of the thermodynamic parameters and transport coefficients higher. Description of the Drawings

[0053] Figure 1 It is a flow chart of a method for predicting the physical properties of arc plasma according to an embodiment of this application;

[0054] Figure 2 It is a mass density diagram of arc plasma with different C2F4 volume fractions in a self - energy circuit breaker according to an embodiment of this application at different pressures and within a temperature range of 300K - 30000K;

[0055] Figure 3 It is a specific enthalpy diagram of arc plasma with different C2F4 volume fractions in a self - energy circuit breaker according to an embodiment of this application at different pressures and within a temperature range of 300K - 30000K;

[0056] Figure 4 It is a specific heat at constant pressure diagram of arc plasma with different C2F4 volume fractions in a self - energy circuit breaker according to an embodiment of this application at different pressures and within a temperature range of 300K - 30000K;

[0057] Figure 5 It is a conductivity diagram of arc plasma with different C2F4 volume fractions in a self - energy circuit breaker according to an embodiment of this application at different pressures and within a temperature range of 300K - 30000K;

[0058] Figure 6 It is a thermal conductivity diagram of arc plasma with different C2F4 volume fractions in a self - energy circuit breaker according to an embodiment of this application at different pressures and within a temperature range of 300K - 30000K;

[0059] Figure 7 It is a viscosity coefficient diagram of arc plasma with different C2F4 volume fractions in a self - energy circuit breaker according to an embodiment of this application at different pressures and within a temperature range of 300K - 30000K;

[0060] Figure 8Principle block diagram of an apparatus for predicting physical property parameters of an arc plasma according to an embodiment of the present application. Detailed implementation manners

[0061] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of the specific implementation manners of the present invention in conjunction with the accompanying drawings of the specification. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0062] In the following description, many specific details are set forth to facilitate a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0063] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an individual or alternative embodiment that is mutually exclusive with other embodiments.

[0064] Embodiment 1:

[0065] A method for predicting physical property parameters of an arc plasma, as Figure 1 shown, includes:

[0066] Step S1: Obtain an arc extinguishing medium containing polytetrafluoroethylene;

[0067] In this embodiment, during the arc interruption process of the self-powered circuit breaker, the nozzle material generates polytetrafluoroethylene vapor due to ablation and mixes into the arc extinguishing medium, obtaining an arc extinguishing medium containing polytetrafluoroethylene (C2F4). C2F4 is not a substance directly added to the mixed gas. At room temperature, C2F4 is a solid nozzle material. In the prior art, the arc extinguishing medium is SF6. When the arc burns, the temperature is very high, and the nozzle material C2F4 directly evaporates into a gas and mixes into the SF6 arc. For environmental protection substitution and to avoid using SF6, now we need to study the gas arc extinguishing medium of C4F7N / CO2. During combustion, the nozzle material C2F4 will still turn into vapor and mix into C4F7N / CO2, forming a mixed gas of C4F7N / CO2 / C2F4. However, there is currently no relevant calculation method for the physical properties of the arc plasma of this mixed gas. Regarding the arc extinguishing ability of the gas C4F7N / CO2, arc simulation calculations need to be carried out. Also, due to the influence of nozzle material ablation, in order to accurately evaluate the arc extinguishing ability of C4F7N / CO2, it is actually necessary to calculate the physical properties of the arc of the C4F7N / CO2 / C2F4 mixed gas.

[0068] Step S2: Obtain the particle components of the arc plasma of the arc extinguishing medium under different pressures and different temperatures in a variable electric field environment;

[0069] In this embodiment, the Gibbs free energy minimization method is used to obtain the particle components of the arc plasma of the arc extinguishing medium.

[0070] Step S3: Calculate the thermodynamic parameters of the arc plasma according to the particle components of the arc plasma of the arc extinguishing medium;

[0071] In this embodiment, the method of statistical thermal physics is used to calculate the thermodynamic parameters of the arc plasma.

[0072] Step S4: Calculate the transport coefficients of the arc plasma. The thermodynamic parameters and the transport coefficients are the physical properties of the arc plasma.

[0073] In this embodiment, the Chapman-Enskog approximation method is used to calculate the transport coefficients of the arc plasma.

[0074] In step S2, obtain the gas arc plasma components under different pressures and different temperatures in a variable electric field environment.

[0075] Specifically, the plasma satisfies the mass conservation constraint condition, the charge quasi-neutral condition, and Dalton's law of partial pressures; the mass conservation constraint condition is:

[0076]

[0077] Among them, a ij is the stoichiometric number of element j in chemical particle i, is the number of moles of element j in the total chemical reaction, determined by calculating the initial conditions, l is the number of types of elements in the system, is the number of moles of particle i per kilogram of the mixed gas, and w is the upper limit of the operation.

[0078] The charge quasi-neutrality condition is:

[0079]

[0080] Among them, z i is the charged number of particle i, is the number of moles of electrons per kilogram of the mixed gas.

[0081] Dalton's law of partial pressures is:

[0082]

[0083] Among them, n i is the number density of particle i, λ D is the Debye length, and the screening effect of ions is ignored during the calculation.

[0084] Based on the Gibbs minimum free energy principle, the particle composition of the arc extinguishing medium with a certain volume fraction of C2F4 is calculated. The formula for calculating the Gibbs free energy is as follows:

[0085]

[0086] Among them, w is the number of particles in the system, g is the Gibbs free energy of the system, is the number of moles of particle i per kilogram of the mixed gas, μ i is the chemical potential of particle i, and the definition formula is as follows:

[0087]

[0088] Among them, is the chemical potential of the standard state of particle j, is the chemical potential of the standard state of particle i, R is the ideal gas constant, T is the temperature, P is the pressure, is the standard of particle i, is the standard entropy of particle i.

[0089] Under local thermodynamic equilibrium, both the objective function (minimization of Gibbs free energy) and the constraint conditions (chemical stoichiometry conservation, charge quasi-neutrality condition, Dalton partial pressure) for calculating plasma components are non-linear, and generally solved by numerical iterative calculation. Lagrange multipliers and the steepest descent Newton-Raphson iteration method are widely used to solve the particle composition problem of arc plasma under local thermodynamic equilibrium.

[0090] In step S3, the thermodynamic parameters include: the mass density of the arc plasma, the specific enthalpy of the arc plasma, and the specific heat at constant pressure of the arc plasma.

[0091] The mass density of the arc plasma, as Figure 2 shown, the calculation formula is as follows:

[0092]

[0093] where ρ is the mass density of the arc plasma, m i is the mass of particle i, n i is the number density of the i-th particle, and w is the total number of particle species.

[0094] The specific enthalpy of the arc plasma, as Figure 3 shown, the calculation formula is as follows:

[0095]

[0096] where h is the enthalpy of a unit mass of substance, called specific enthalpy, x i is the mole fraction of particle i, is the standard enthalpy of formation, M is the molar mass of the plasma, and w is the upper limit of the summation.

[0097] The specific heat at constant pressure of the arc plasma, as Figure 4 shown, the calculation formula is as follows:

[0098]

[0099] where C p is the change in specific thermodynamic energy per unit mass of substance when the temperature increases by 1 K under constant pressure conditions, called specific heat at constant pressure, h is the enthalpy of a unit mass of substance, and T is the temperature of the arc plasma.

[0100] In step S4, the transport coefficients include: the electrical conductivity of the arc plasma, the thermal conductivity of the arc plasma, and the viscosity coefficient of the arc plasma.

[0101] The electrical conductivity of the arc plasma is calculated as follows:

[0102]

[0103] wherein, m1 is the electron mass; m i is the mass of particle i; m j is the mass of particle j, is the collision integral of order l, s for the interaction between particles i and j. If it is the collision integral of electrons, there is no i, j; is the collision cross section of order l for the interaction between particles i and j; γ ij is the initial velocity at the initialization of the interaction between particles i and j; μ ij is the reduced mass of the interaction between particles i and j; g ij The relative initial velocity of the interaction between particles i and j; x is the refraction angle of the colliding particles relative to the center of the gravity coordinate system; is the interaction potential between particle collisions; b is the impact parameter, T is the temperature, l is the parameter related to the collision process, σ elec is the electrical conductivity of the arc plasma, n1 is the electron number density, m1 is the electron mass, k B is the Boltzmann constant, q 00 ~q 22 are the coefficients related to the interaction between electrons and heavy particles in the plasma: q 00 is the coefficient related to the (1,1) - order collision integral Q (1,1) ; q 01 is the coefficient related to the (1,1) - (1,2) - order collision integrals Q (1,1) 、Q (1,2) ; q 11 is the coefficient related to the (1,1) - (2,2) - order collision integrals Q (1,1) ~Q (2,2) ; q 02 is the coefficient related to the (1,1) - (1,3) - order collision integrals Q (1,1) ~Q (1,3) ; q 12 is the coefficient related to the (1,1) - (2,3) - order collision integrals Q (1,1) ~Q (2,3) ; q 22 is the coefficient related to the (1,1) - (2,4) - order collision integrals Q (1,1) ~Q (2,4) ; ; r m is a characteristic distance related to the interaction between particles in the plasma; r is the integration variable, g ij is the relative velocity of particle i and particle j.

[0104] The thermal conductivity of the arc plasma, as Figure 6 shown, includes: electron thermal conductivity, heavy particle thermal conductivity, internal thermal conductivity and reaction thermal conductivity, and the calculation formulas are as follows:

[0105] λtotal = λ e + λ H + λ int + λ react

[0106] where λ total is the thermal conductivity of the arc plasma, λ e is the electron thermal conductivity, λ H is the heavy particle thermal conductivity, λ int is the internal thermal conductivity, λ react is the reaction thermal conductivity.

[0107] The electron thermal conductivity, as Figure 5 shown, has the following calculation formula:

[0108]

[0109] where λ e is the electron thermal conductivity, k B is the Boltzmann constant; R is the ideal gas constant, T is the temperature, n1 is the electron number density, and M1 is the electron mass.

[0110] The calculation formula for the heavy particle thermal conductivity is as follows:

[0111]

[0112] where λ H is the heavy particle thermal conductivity, k ii is the translational thermal conductivity of the ii system, k ij is the translational thermal conductivity of the ij system, L vv is the element in the v-th row and v-th column of the matrix λ H , L ii is the coefficient related to the particle species, L ij is a physical quantity used to measure the influence of the interaction between different particle species i and j on the thermal conductivity; M i is the molar mass of particle i, M k is the molar mass of particle k, M j is the molar mass of particle j; is the coefficient describing the interaction characteristics between the i-th particle and the k-th particle in the arc plasma, is the coefficient describing the interaction characteristics between the i-th particle and the k-th particle in the arc plasma, is the coefficient describing the interaction characteristics between the i-th particle and the j-th particle in the arc plasma; x i is the mole fraction of particle i, x j is the mole fraction of particle j; v is the total number of particle species in the arc plasma;

[0113] The internal thermal conductivity is calculated as follows:

[0114]

[0115] where λ int is the internal thermal conductivity, λ int i is the internal thermal conductivity of particle i, D ij is the binary diffusion coefficient of particle ij, D ij (l) is the first-order estimate of the binary diffusion coefficient between particles kl, P is the pressure, D ii (l) is the coefficient related to the diffusion characteristics of the same kind of particles in the arc plasma, N a is Avogadro's constant, is the collision integral of the particles, and N is the total number of particle species.

[0116] The reaction thermal conductivity is calculated as follows:

[0117]

[0118] where λ react is the reaction thermal conductivity, ΔH μ is the enthalpy change of reaction μ, T is the temperature of the arc plasma, a ik is the stoichiometric coefficient of the kth particle in the ith chemical reaction, R is the ideal gas constant; P is the pressure of the arc plasma, A ij is the interaction coefficient between the ith particle and the jth particle in the arc plasma, A μμ is the self-interaction coefficient of the μth particle, D kl (l) is the diffusion coefficient of the particles, a il is the stoichiometric coefficient of the ith particle in the lth chemical reaction, a jk is the stoichiometric coefficient of the jth particle in the kth chemical reaction, a jl is the stoichiometric coefficient of the jth particle in the lth chemical reaction; x k is the mole fraction of particle k, x l is the mole fraction of particle l, and v is the total number of particle species in the arc plasma.

[0119] The viscosity coefficient of the arc plasma, as Figure 7 shown, is calculated as follows:

[0120]

[0121]

[0122] where η is the viscosity coefficient of the arc plasma, ηij is the viscosity of the system composed of particles ij; x i is the mole fraction of particle i; M i is the molar mass of particle i; M j is the molar mass of particle j, v is the number of heavy particle species other than electrons, l is the number of element species in the system, η ik is the viscosity of the system composed of particles ik; x i is the mole fraction of particle i, x k is the mole fraction of particle k, x v is the mole fraction of particle v; M i is the molar mass of particle i; M j is the molar mass of particle j, M k is the molar mass of particle k; v is the number of heavy particle species other than electrons, l is the number of element species, H vv is the self - interaction coefficient of the v - th particle.

[0123] As can be seen from the above technical solutions, a method for predicting the physical property parameters of arc plasma provided by this application includes: obtaining an arc - extinguishing medium containing C2F4; according to the arc - extinguishing medium, using the Gibbs free energy minimization method to obtain the corresponding particle composition of the arc plasma; calculating the thermodynamic parameters of the plasma according to the standard statistical thermophysics method, including mass density ρ, specific enthalpy h, and specific heat at constant pressure C p ; calculating the transport coefficients of the plasma according to the Chapman - Enskog approximation method, including electrical conductivity σ elec 、thermal conductivity λ total and viscosity coefficient η.

[0124] Example 2:

[0125] This example proposes a device for predicting the physical property parameters of arc plasma, as Figure 8 shown, including: a medium acquisition module, a particle composition acquisition module, a parameter calculation module, and a coefficient calculation module. The medium acquisition module is connected to the particle composition acquisition module, the particle composition acquisition module is connected to the parameter calculation module, and the parameter calculation module and the coefficient calculation module jointly determine the physical property parameters of the arc plasma;

[0126] The medium acquisition module is used to obtain an arc - extinguishing medium containing polytetrafluoroethylene;

[0127] The particle composition acquisition module is used to obtain the particle composition of the arc plasma of the arc - extinguishing medium under different pressures and different temperature conditions in a variable - electric - field environment;

[0128] The parameter calculation module is used to calculate the thermodynamic parameters of the arc plasma according to the particle composition of the arc plasma of the arc - extinguishing medium;

[0129] A coefficient calculation module for calculating the transport coefficients of arc plasma, where the thermodynamic parameters and transport coefficients are the physical property parameters of arc plasma.

[0130] Example 3:

[0131] This example provides an electronic device, including: one or more processors, and a memory. The memory is used to store instructions, and when the instructions are executed by the one or more processors, the one or more processors are caused to execute the method for predicting the physical property parameters of arc plasma as described above.

[0132] The electronic device can be a mobile phone, a computer, a tablet computer, etc., including a memory and a processor. A computer program is stored on the memory, and when the computer program is executed by the processor, it implements a method for predicting the physical property parameters of arc plasma as described in the example. It can be understood that the electronic device can also include an input / output (I / O) interface and a communication component.

[0133] Among them, the processor is used to execute all or part of the steps in the method for predicting the physical property parameters of arc plasma as described in the above example. The memory is used to store various types of data, which can include, for example, instructions for any application program or method in the electronic device, and data related to the application program.

[0134] The processor can be implemented by an application specific integrated circuit (ASIC), a digital signal processor (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute the method for predicting the physical property parameters of arc plasma as described in the above example.

[0135] Example 4:

[0136] This example provides a computer-readable storage medium that stores executable instructions. When the instructions are executed and implemented in the form of a software functional unit and sold or used as an independent product, they can be stored in a computer-readable storage medium.

[0137] The computer software product is stored in a storage medium, including a number of instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of a method for predicting physical property parameters of an arc plasma described in various embodiments of the present application.

[0138] The aforementioned storage medium includes: flash memory, hard disk, multimedia card, card-type memory (such as SD (Secure Digital Memory Card, secure digital memory card) or DX (abbreviation for Memory Data Register, MDR, memory data register) memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disk, server, APP (abbreviation for Application, application software) application mall, and other various media that can store program check codes. A computer program is stored thereon, and when the computer program is executed by a processor, the various steps of the aforementioned method for predicting physical property parameters of an arc plasma can be implemented.

[0139] Embodiment 5:

[0140] This embodiment provides a computer program product, including a computer program or instructions, and when the computer program or instructions are executed by a processor, the aforementioned method for predicting physical property parameters of an arc plasma is implemented.

[0141] Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a computer program product.

[0142] The various embodiments in the present application are described in a progressive manner. For the same or similar parts among the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments.

[0143] The protection scope of the present application is not limited to the above embodiments. Obviously, those skilled in the art can make various changes and deformations to the present disclosure without departing from the scope and spirit of the present disclosure. If these changes and deformations fall within the scope of the claims of the present disclosure and their equivalent technologies, the intention of the present disclosure also includes these changes and deformations.

Claims

1. A method for predicting physical property parameters of arc plasma, characterized in that, Comprising: Obtaining an arc extinguishing medium containing polytetrafluoroethylene; Under different pressure and different temperature conditions in a variable electric field environment, obtaining the particle components of the arc plasma of the arc extinguishing medium; Calculating the thermodynamic parameters of the arc plasma according to the particle components of the arc plasma of the arc extinguishing medium; Calculating the transport coefficients of the arc plasma, where the thermodynamic parameters and the transport coefficients are the physical property parameters of the arc plasma.

2. The prediction method of arc plasma physical property parameters according to claim 1, wherein The thermodynamic parameters include: the mass density of the arc plasma, the specific enthalpy of the arc plasma, and the specific heat at constant pressure of the arc plasma.

3. A method for predicting the physical property parameters of an arc plasma according to claim 2, characterized in that, The calculation formula for the mass density of the arc plasma is as follows: where ρ is the mass density of the arc plasma, m i is the mass of particle i, n i is the number density of the i-th species of particles, that is, the particle composition of the arc plasma of the arc quenching medium, and w is the total number of particle species.

4. A method for predicting physical property parameters of an arc plasma according to claim 2, characterized in that The calculation formula for the specific enthalpy of the arc plasma is as follows: where h is the enthalpy of the substance per unit mass, called specific enthalpy, x i is the mole fraction of particle i, is the standard enthalpy of formation, M is the molar mass of the plasma, and w is the total number of particle species.

5. A method for predicting physical property parameters of an arc plasma according to claim 2, characterized in that, The calculation formula for the specific heat at constant pressure of the arc plasma is as follows: Among them, C p is the change value of the specific thermodynamic energy when the temperature of a substance with a unit mass increases by 1 K under constant pressure conditions, which is called the specific heat at constant pressure, h is the enthalpy of a substance with a unit mass, and T is the temperature of the arc plasma.

6. A method for predicting physical property parameters of an arc plasma according to claim 1, characterized in that, The transport coefficients include: the electrical conductivity of the arc plasma, the thermal conductivity of the arc plasma, and the viscosity coefficient of the arc plasma.

7. A method for predicting physical property parameters of an arc plasma according to claim 6, characterized in that, The calculation formula for the electrical conductivity of the arc plasma is as follows: where, σ elec is the electrical conductivity of the arc plasma, n1 is the electron number density, m1 is the electron mass, k B is the Boltzmann constant, T is the temperature of the arc plasma, m i is the mass of particle i; m j is the mass of particle j; q 00 ~q 22 are coefficients related to the interaction between electrons and heavy particles in the plasma: q 00 is the coefficient related to the (1,1)-order collision integral Q (1,1) ; q 01 is the coefficient related to the (1,1)–(1,2)-order collision integrals Q (1,1) , Q (1,2) ; q 11 is the coefficient related to the (1,1)–(2,2)-order collision integrals Q (1,1) ~Q (2,2) ; q 02 is the coefficient related to the (1,1)–(1,3)-order collision integrals Q (1,1) ~Q (1,3) ; q 12 is the coefficient related to the (1,1)–(2,3)-order collision integrals Q (1,1) ~Q (2,3) ; q 22 is the coefficient related to the (1,1)–(2,4)-order collision integrals Q (1,1) ~Q (2,4) ; is the l, s-order collision integral of the interaction between particles i and j, is the l-order collision cross section of the interaction between particles i and j; γ ij is the initial velocity of the interaction between particles i and j, μ ij is the reduced mass of the interaction between particles i and j, g ij is the relative initial velocity of the interaction between particles i and j, x is the refraction angle of the colliding particles relative to the center of the gravity coordinate system, is the interaction potential between particle collisions, b is the collision parameter, r m is a characteristic distance related to the interaction between particles in the plasma; r is the distance between particles, g ij is the relative velocity of particles i and j.

8. A method for predicting the physical property parameters of an arc plasma according to claim 6, characterized in that, The thermal conductivity of the arc plasma includes: electron thermal conductivity, heavy particle thermal conductivity, internal thermal conductivity, and reaction thermal conductivity, and the calculation formula is as follows: λ total = λ e + λ H + λ int + λ react Among them, λ total is the thermal conductivity of the arc plasma, λ e is the electron thermal conductivity, λ H is the heavy particle thermal conductivity, λ int is the internal thermal conductivity, λ react is the reaction thermal conductivity.

9. A method for predicting the physical property parameters of an arc plasma according to claim 8, characterized in that The calculation formula for the electron thermal conductivity is as follows: Among them, λ e is the electronic thermal conductivity, k B is the Boltzmann constant; R is the ideal gas constant, T is the temperature of the arc plasma, n1 is the electron number density, M1 is the electron mass, q 00 ~q 22 are coefficients related to the interaction between particles in the plasma; The calculation formula for the heavy particle thermal conductivity is as follows: Among them, λ H is the heavy particle thermal conductivity, k ii is the translational thermal conductivity of the ii system, k ij is the translational thermal conductivity of the ij system, L vv is the element in the v-th row and v-th column of the matrix λ H in which, L ii is a coefficient related to the particle species, L ij is a physical quantity used to measure the influence of the interaction between different particle species i and j on the thermal conductivity; M i is the molar mass of particle i, M k is the molar mass of particle k, M j is the molar mass of particle j; is the coefficient describing the interaction characteristics between the i-th particle and the k-th particle in the arc plasma, is the coefficient describing the interaction characteristics between the i-th particle and the k-th particle in the arc plasma, is the coefficient describing the interaction characteristics between the i-th particle and the j-th particle in the arc plasma; x i is the molar fraction of particle i, x j is the molar fraction of particle j, v is the total number of particle species in the arc plasma, x v is the molar fraction of particle v; The calculation formula for the internal thermal conductivity is as follows: where λ int is the internal thermal conductivity, λ inti is the internal thermal conductivity of particle i, D ij is the binary diffusion coefficient of particle ij, D ij (l) is the first-order estimate of the binary diffusion coefficient between particles kl, P is the pressure of the arc plasma, D ii (l) is the coefficient related to the diffusion characteristics of the same kind of particles in the arc plasma, N a is the Avogadro constant, is the collision integral of the particles, N is the total number of particle species, M i is the molar mass of particle i, M j is the molar mass of particle j, k B is the Boltzmann constant, and T is the temperature of the arc plasma; The calculation formula for the reaction thermal conductivity is as follows: Among them, λ react is the reaction thermal conductivity, ΔH μ is the enthalpy change of reaction μ, T is the temperature of the arc plasma, a ik is the stoichiometric coefficient of the k-th particle in the i-th chemical reaction, R is the ideal gas constant; P is the pressure of the arc plasma, A ij is the interaction coefficient between the i-th particle and the j-th particle in the arc plasma, A μμ is the self-interaction coefficient of the μ-th particle, D kl (l) is the diffusion coefficient of the particle, a il is the stoichiometric coefficient of the i-th particle in the l-th chemical reaction, a jk is the stoichiometric coefficient of the j-th particle in the k-th chemical reaction, a jl is the stoichiometric coefficient of the j-th particle in the l-th chemical reaction; x k is the mole fraction of the k-particle, x l is the mole fraction of the l-particle, and v is the total number of particle species in the arc plasma.

10. A method for predicting physical property parameters of an arc plasma according to claim 6, characterized in that, The calculation formula for the viscosity coefficient of the arc plasma is as follows: where η is the viscosity coefficient of the arc plasma, η ij is the viscosity of the system composed of particles ij, η ik is the viscosity of the system composed of particles ik; x i is the mole fraction of particle i, x k is the mole fraction of particle k, x v is the mole fraction of particle v, M i is the molar mass of particle i, M j is the molar mass of particle j, M k is the molar mass of particle k, v is the number of heavy particle species other than electrons, l is the number of element species, v is the total number of particle species in the arc plasma, H vv is the self-interaction coefficient of the v-th particle, H 1v is the interaction coefficient between the 1st particle and the v-th particle, H v1 is the interaction coefficient between the v-th particle and the 1st particle.

11. An apparatus for predicting physical property parameters of arc plasma, characterized in that, Comprising: A medium acquisition module for obtaining an arc extinguishing medium containing polytetrafluoroethylene; A particle component acquisition module for obtaining the particle components of the arc plasma of the arc extinguishing medium under different pressure and different temperature conditions in a variable electric field environment; A parameter calculation module for calculating the thermodynamic parameters of the arc plasma according to the particle components of the arc plasma of the arc extinguishing medium; A coefficient calculation module for calculating the transport coefficients of the arc plasma, where the thermodynamic parameters and the transport coefficients are the physical property parameters of the arc plasma.

12. An electronic device, characterized in that, Comprising: One or more processors, and a memory, where the memory is used to store instructions, and when the instructions are executed by the one or more processors, the one or more processors execute an arc plasma physical property parameter prediction method according to any one of claims 1 to 10.

13. A computer-readable storage medium, characterized in that, It stores executable instructions, and when the instructions are executed, the processor executes an arc plasma physical property parameter prediction method according to any one of claims 1 to 10.

14. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by the processor, an arc plasma physical property parameter prediction method according to any one of claims 1 to 10 is implemented.

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