Construction method, system, medium and product of multi-physics field coupling needle-cylinder type electrode gas phase electrofluid system model

Abstract

The invention discloses a multi-physics field coupling needle-cylinder type electrode gas phase electrofluid system model construction method and system, a medium and a product, and the method comprises the steps: constructing a geometric model of a needle-cylinder type electrode gas phase electrofluid system model, and setting material attributes; grid division is carried out on the geometric model of the needle-cylinder type electrode gas phase electrofluid system, multiple physical fields are added, and a multi-physical-field coupling needle-cylinder type electrode gas phase electrofluid system model is obtained; setting boundary conditions; solving the multi-physics field coupling needle-cylinder electrode gas phase electrofluid system model to obtain solving results, and judging whether the solving results are converged or not; if yes, obtaining a multi-physics field coupling needle-barrel type electrode gas phase electrofluid system model; and if not, grid division is carried out on the geometric model of the needle-cylinder type electrode gas phase electrofluid system again until all solving results converge. According to the invention, the microcosmic ionization process and the coupling mechanism between microcosmic ionization and macroscopic fluid dynamic behaviors can be observed more intuitively.

Description

Technical Field

[0001] The present invention relates to the technical field of design and optimization of gas-phase electrofluid power systems, and in particular to a method, system, medium and product for constructing a multi-physics field coupled needle-cylinder electrode gas-phase electrofluid system model. Background Art

[0002] The gas-phase electrohydrodynamic system (EHDGS) is designed to study the gas flow effect under the action of electric field forces. This gas flow phenomenon is called ion wind. When a high voltage is applied to an electrode with a small radius of curvature, corona discharge occurs, generating ion wind. At this time, two non-neutral regions are formed around the electrode. The region close to the electrode is called the ionization zone. Complex chemical reactions occur in this region to produce a large number of charged particles, including collision reactions, adsorption reactions, recombination reactions, and charge transfer reactions of charged particles. The second region is the ion drift region. Monopolar positive and negative ions are accelerated according to the voltage polarity and move to the grounded electrode. In these regions, ions frequently collide with neutral molecules, resulting in momentum transfer. Ion wind generating devices have the advantages of low vibration and noise, easy miniaturization, low energy consumption, and no pollution. Their applications in electronic device thermal management, microfluidics regulation, microrobot drive, drug delivery, small aircraft propulsion systems, etc. are considered to be viable alternatives to traditional technologies.

[0003] Previous research has revealed that many researchers have used experimental methods to study and explore the parameters that influence EHDGS performance. However, the design and development of EHDGS relies heavily on combining experiments with simulations to verify the coupled motion mechanisms of the flow and electric fields. Simulation is a key tool for understanding the mechanisms of electrofluid generation, optimizing designs, and predicting performance. For gas ionization processes that cannot be directly observed experimentally, ionization modeling and simulation can serve as an effective means of observing their internal reactions and mechanisms. Summary of the Invention

[0004] In order to solve the technical problems existing in the background technology, the present invention proposes a method, system, medium and product for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model.

[0005] The present invention proposes a method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model, comprising:

[0006] Construct the geometric model of the needle-cylinder electrode gas-phase electrofluid system model;

[0007] Set the material properties of the geometry of the needle-cylinder electrode gas-phase electrofluidic system model;

[0008] Meshing the geometric model of the needle-cylinder electrode gas-phase electric fluid system to obtain a mesh model of the needle-cylinder electrode gas-phase electric fluid system;

[0009] Adding multiphysics to the mesh model of the needle-cylinder electrode gas-phase current fluid system creates a multiphysics-coupled needle-cylinder electrode gas-phase current fluid system model. The multiphysics includes the electric field, gas ionization process, space charge density field, and flow field. The multiphysics-coupled needle-cylinder electrode gas-phase current fluid system model includes the electric field governing equations, electron transport equations, space charge transport equations, and flow field governing equations.

[0010] Set the boundary conditions for the multi-physics coupled needle-cylinder electrode gas-phase electrofluidic system model;

[0011] The multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is solved to obtain solution results, and it is determined whether the solution results are converged; if so, the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is obtained; if not, the needle-cylinder electrode gas-phase current fluid system geometric model is re-meshed until the solution results are converged.

[0012] Preferably, the electric field governing equation is

[0013]

[0014] Where, is the Laplace operator, ε0 is the dielectric constant of air; is the electric potential; N p 、N m 、N e are the positive ion, negative ion and electron densities respectively, e is the elementary charge, and E is the electric field strength.

[0015] Preferably, the electron transport equation is

[0016]

[0017] Where N e is the electron density; is the Laplace operator, Γ e is the electron flux; R e is the reaction in which electrons participate; where R e Including R1~R20;D e is the electron diffusion rate, μ e is the electron mobility, e is the electric field strength;

[0018] Where R1 is e+N2→2e+N2 + ; R2 is e+O2→2e+O2 + ; R3 is e+O2→O - +O; R4 is e+2O2→O2 - +O2; R5 is N2 ++2e→N2+e; R6 is O4 + +e→2O2; R7 is O2 + +e→2O; R8 is N2 + +e+N2→2N2; R9 is O4 + +O2 - →3O2; R10 is O4 + +O2 - +N2→3O2+N2; R11 is O2 + +O2 - +N2→2O2+N2; R12 is N2 + +O2→O2 + +N2; R13 is 2N2+O2 + →N2O2 + +N2; R14 is N2O2 + +N2→O2 + +2N2; R15 is N2O2 + +O2→O4 + +N2; R16 is O2 + +O2+N2→O4 + +N2; R17 is O+O2+N2→O3+N2; R 18 is O - +O2 + →O+O2; R19 is N2 + +N2+O2→N4 + +O2;R20N4 + +O2→O2 + +2N2.

[0019] Preferably, the space charge transport equation is q = -e(N p -N m -N e );where q is space charge, e is elementary charge, N p 、N m 、N e are the positive ion, negative ion and electron densities, respectively.

[0020] Preferably, the flow field governing equation is

[0021] Where, is the Laplace operator, ρ = 1.23 kg / m 3 is the air density, p is the air pressure, μ=1.79×10 -5 N·s / m 2 is the dynamic viscosity coefficient of air, F e is the body force, F e=qE, q is the space charge, E is the electric field strength, and u is the velocity.

[0022] Preferably, the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is solved to obtain a solution, which specifically includes:

[0023] Solve the electron transport equation to obtain the distribution of charged particles;

[0024] According to the distribution of charged particles and the electric field control equation, the distribution of the electric field potential in space is obtained;

[0025] According to the distribution of charged particles and the spatial charge transport equation, the spatial charge density distribution is obtained; according to the distribution of the spatial electric field potential, the spatial charge density distribution and the process control equation, the velocity and pressure are obtained;

[0026] The distribution of charged particles, the distribution of electric field potential in space, the distribution of charge density in space and the combination of velocity and pressure are taken as the solution results.

[0027] Preferably, solving the electron transport equation to obtain the distribution of charged particles specifically includes:

[0028] The collision cross section data of N2 and O2 in the air were obtained through the LXCat database;

[0029] The collision cross section data of N2 and O2 are input into the Boltzmann equation respectively, and the electron energy distribution functions of N2 and O2 are obtained by solving them;

[0030] The electron energy distribution functions of N2 and O2 are solved separately to obtain the transport parameters of charged particles;

[0031] The transport parameters of charged particles are input into the electron transport equation to obtain the distribution of charged particles.

[0032] In a second aspect, the present invention further proposes a system for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model, comprising:

[0033] A geometric model building module is used to build a geometric model of a needle-cylinder electrode gas-phase fluid system model;

[0034] A material property setting module is used to set the material properties of the geometric model of the needle-cylinder electrode gas-phase current fluid system model;

[0035] A meshing module is used to mesh the geometric model of the needle-cylinder electrode gas-phase current fluid system to obtain a mesh model of the needle-cylinder electrode gas-phase current fluid system;

[0036] A physics field addition module is used to add multiphysics fields to the mesh model of the needle-cylinder electrode gas-phase current fluid system to obtain a multiphysics field coupled needle-cylinder electrode gas-phase current fluid system model. The multiphysics fields include: electric field, gas ionization process, space charge density field, and flow field. The multiphysics field coupled needle-cylinder electrode gas-phase current fluid system model includes: electric field governing equations, electron transport equations, space charge transport equations, and flow field governing equations.

[0037] Boundary condition setting module, used to set the boundary conditions of the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model;

[0038] A solution module is used to solve the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model and obtain the solution result;

[0039] A judgment module is used to judge whether the solution results are converged; if so, a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is obtained;

[0040] The meshing module is also used to re-mesh the geometric model of the needle-cylinder electrode gas-phase current fluid system when the solution results have not converged until the solution results have converged.

[0041] In a third aspect, the present invention further proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model as described in any one of the foregoing.

[0042] In a fourth aspect, the present invention further proposes a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model described in any one of the first aspects.

[0043] In the present invention, the proposed method, system, medium and product for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model are obtained by adding four physical fields, namely, electric field, gas ionization process, space charge density field and flow field, to the grid model of the needle-cylinder electrode gas-phase current fluid system. The multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model can capture the development of electron avalanche, space charge effect and non-equilibrium phenomenon in the ionization process, and may be more accurate in predicting the discharge starting voltage, current waveform, space charge distribution, etc., and describe the dynamic behavior of electrons in more detail, which is conducive to providing more accurate numerical simulation results of electric field, gas ionization process, space charge density field and flow field, and more intuitively observing the microscopic ionization process and the coupling mechanism between microscopic ionization and macroscopic fluid dynamic behavior. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of a flow chart of a method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model in one embodiment of the present invention.

[0045] Figure 2 Schematic diagram of a grid model of a needle-cylinder type electrode gas-phase current fluid system in one embodiment of the present invention.

[0046] Figure 3 It is a schematic diagram of the solution results of the grid model of the needle-cylinder type electrode gas-phase current fluid system in one embodiment of the present invention.

[0047] Figure 4 Schematic diagram of simulation results and experimental results of a grid model of a needle-cylinder type electrode gas-phase current fluid system in one embodiment of the present invention. DETAILED DESCRIPTION

[0048] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0049] First, as Figure 1 As shown, the present invention proposes a method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model, comprising:

[0050] Construct the geometric model of the needle-cylinder electrode gas-phase electrofluid system model;

[0051] Set the material properties of the geometry of the needle-cylinder electrode gas-phase electrofluidic system model;

[0052] The geometric model of the needle-cylinder electrode gas-phase current fluid system is meshed to obtain the mesh model of the needle-cylinder electrode gas-phase current fluid system, as shown in Figure 2 As shown;

[0053] Adding multiphysics to the mesh model of the needle-cylinder electrode gas-phase current fluid system creates a multiphysics-coupled needle-cylinder electrode gas-phase current fluid system model. The multiphysics includes the electric field, gas ionization process, space charge density field, and flow field. The multiphysics-coupled needle-cylinder electrode gas-phase current fluid system model includes the electric field governing equations, electron transport equations, space charge transport equations, and flow field governing equations.

[0054] Set the boundary conditions for the multi-physics coupled needle-cylinder electrode gas-phase electrofluidic system model;

[0055] Solving the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model to obtain solution results, and determining whether the solution results are converged; if so, obtaining the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model based on the solution results;

[0056] If not, the geometric model of the needle-cylinder electrode gas-phase current fluid system is re-meshed until the solution results converge.

[0057] The present invention adds four physical fields, namely, electric field, gas ionization process, space charge density field and flow field, to the grid model of the needle-cylinder electrode gas-phase current fluid system to obtain a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model. The model can capture the development of electron avalanche, space charge effect and non-equilibrium phenomenon in the ionization process, and may be more accurate in predicting the discharge starting voltage, current waveform, space charge distribution, etc., and describes the dynamic behavior of electrons in more detail, which is conducive to providing more accurate numerical simulation results of the electric field, gas ionization process, space charge density field and flow field, and more intuitively observing the microscopic ionization process and the coupling mechanism between microscopic ionization and macroscopic fluid dynamic behavior.

[0058] When judging whether the solution results have converged, it is converged when the residual is stable within the tolerance range, where the tolerance is set to 10 -4 .

[0059] The corona discharge process excites a large number of charged particles, resulting in the accumulation and drift of space charges, which will affect the original electric field. Therefore, the Poisson equation is used to calculate the electrostatic field. Among them, the electric field control equation is

[0060] Where ε0 is the dielectric constant of air; is the electric potential; N p 、N m 、N e are the positive ion, negative ion and electron densities respectively, E is the electric field intensity, is the Laplace operator.

[0061] In this embodiment, considering the collision reaction between electrons and O2 and N2, the electrons are described by the electron transport equation:

[0062]

[0063] Where D e is the electron density; is the Laplace operator, Γ e is the electron flux; R e It is a reaction involving electrons, that is, R1~R20, μ e is the electron mobility; D e is the electron diffusion rate;

[0064] Among them, the calculation formula for the N2 ionization reaction rate is Where m eis the electron mass; ε is the electron energy; is the collision cross section of N2; f(ε) is the electron energy distribution function. Similarly, calculate the O2 ionization rate.

[0065] The transport parameters of charged particles include electron mobility and electron diffusion rate. The calculation formulas for the reduced electron mobility and reduced electron diffusion rate are:

[0066]

[0067] Where μ e is the electron mobility; D e is the electron diffusion rate; N n is the total neutral particle number density; σ m is the total momentum collision cross section; ε is the average electron energy; and δ is a constant.

[0068] The gas ionization process in this embodiment includes air collision reaction and surface reaction.

[0069] Among them, the air collision reactions R1 to R20 are shown in Table 1, and the surface reactions are shown in Table 2.

[0070] Table 1 Air collision reaction

[0071]

[0072]

[0073] Table 2 Surface reactions

[0074] Index Reaction formula S1 <![CDATA[N2 + →N2]]> S2 <![CDATA[O2 + →O2]]> S3 <![CDATA[N4 + →2N2]]> S4 <![CDATA[O4 + →2O2]]> S5 <![CDATA[N2O2 + →N2+O2]]> S6 <![CDATA[O2 - →O2]]> S7 <h2 style=";text-align:left;direction:ltr"><![CDATA[O <h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> →0.5O2]]><h2 style=";text-align:left;direction:ltr">

[0075] It should be understood that in Table 1, the unit of the two-body collision reaction rate is m 3 / (s·mol), the unit of three-body collision reaction rate is m 6 / (s·mol 2 ), the reaction rate f(ε) of R1-R3 is solved by the collision cross section, N A is Avogadro's constant.

[0076] In this embodiment, a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is solved to obtain the solution, which specifically includes:

[0077] Solve the electron transport equation to obtain the distribution of charged particles; the charged particles include N2 + 、N4 + 、N2O2 + 、O2 + 、O4 + 、O2 - , O- and electron e;

[0078] According to the distribution of charged particles and the electric field control equation, the distribution of the electric field potential in space is obtained; wherein the distribution of the electric field potential in space includes the electric potential;

[0079] According to the distribution of charged particles and the space charge transport equation, the space charge density distribution is obtained; wherein the space charge density distribution includes space charge;

[0080] According to the distribution of electric field potential in space, the distribution of charge density in space and the process control equation, the velocity and pressure are obtained;

[0081] The distribution of charged particles, the distribution of electric field potential in space, the distribution of charge density in space and the combination of velocity and pressure are taken as the solution results.

[0082] In a further embodiment, solving the electron transport equation to obtain the distribution of charged particles specifically includes:

[0083] The collision cross section data of N2 and O2 in the air were obtained through the LXCat database;

[0084] The collision cross section data of N2 and O2 are input into the Boltzmann equation respectively, and the electron energy distribution functions of N2 and O2 are obtained by solving them;

[0085] The electron energy distribution functions of N2 and O2 are solved separately to obtain the transport parameters of charged particles;

[0086] The transport parameters of charged particles are input into the electron transport equation to obtain the distribution of charged particles.

[0087] Corona discharge involves the formation of electron avalanche, where electrons are accelerated in an electric field and collide with gas molecules, resulting in ionization. Ionization produces a large number of charged particles, among which heavy ions (charged particles other than electrons, such as N2 + ) are driven by the electric field to migrate toward the ground electrode, and during the migration process, they collide with neutral molecules and transfer momentum to form an ion wind. This embodiment directly derives these parameters through air collision and first-principles calculations, which can capture the transient characteristics of the generation and annihilation of microscopic particles during the ionization process. This may be more accurate for predicting the discharge starting voltage, current waveform, spatial charge distribution, etc., and describes in more detail a series of non-equilibrium dynamic processes such as gas ionization, charged particle migration, collision energy transfer, etc. during corona discharge. In addition, the generation mechanism of ion wind is explained more clearly on a macro scale. Therefore, the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model obtained is more accurate.

[0088] In step (1), the Boltzmann equation is expressed as:

[0089]

[0090] Where f is the electron distribution in the six-dimensional phase space; v is the electron velocity; e is the elementary charge; E is the electric field intensity; m is the mass of the electron; is the gradient operator of velocity; C is the collision phase of the collision process affecting f.

[0091] In this embodiment, the space charge transport equation is q=-e(N p -N m -N e );where q is space charge, e is elementary charge, N p 、N m 、N e are the positive ion, negative ion and electron densities, respectively.

[0092] In the COMSOL software's built-in physics, select the Plasma Module for the calculation. In the Plasma Module, select the Plasma Interface as the physics interface to be solved, and keep all other settings as default. In the Flow Study Module, select the Plasma Interface and the Flow Interface as the physics interfaces to be solved. Set the initial value of the dependent variable to the results of the space charge study, and keep all other settings as default.

[0093] Corona discharge is a low-temperature plasma whose temperature effect can usually be ignored. It is assumed that the ambient air has a constant density and viscosity, the flow is laminar, and the airflow satisfies the continuity equation and the Navier-Stokes equation.

[0094] In this embodiment, the flow field control equation is Where, is the Laplace operator, ρ = 1.23 kg / m 3 is the air density, p is the air pressure, μ=1.79×10 -5 N·s / m 2 is the dynamic viscosity coefficient of air, F e is the body force, assuming that the body force is dominated by Coulomb force only, which is given by the following formula: e =qE, q is the space charge, E is the electric field strength, and u is the velocity.

[0095] In the built-in physics field of COMSOL software, single-phase laminar flow in the fluid flow module is selected as the flow field.

[0096] In this embodiment, a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is solved to obtain the solution, which specifically includes:

[0097] Solve the electron transport equation to obtain the distribution of charged particles; the distribution of charged particles includes N2 +、N4 + 、N2O2 + 、O2 + 、O4 + 、O2 - , O - and the distribution of electrons e;

[0098] According to the distribution of charged particles and the electric field control equation, the distribution of the electric field potential in space is obtained; wherein the distribution of the electric field potential in space includes the electric potential;

[0099] According to the distribution of charged particles and the space charge transport equation, the space charge density distribution is obtained; wherein the space charge density distribution includes space charge;

[0100] According to the distribution of electric field potential in space, the distribution of charge density in space and the process control equation, the velocity and pressure are obtained;

[0101] The distribution of charged particles, the distribution of electric field potential in space, the distribution of charge density in space and the combination of velocity and pressure are taken as the solution results.

[0102] In a further embodiment, solving the electron transport equation to obtain the distribution of charged particles specifically includes:

[0103] The collision cross section data of N2 and O2 in the air were obtained through the LXCat database;

[0104] The collision cross section data of N2 and O2 are input into the Boltzmann equation respectively, and the electron energy distribution functions of N2 and O2 are obtained by solving them;

[0105] The electron energy distribution functions of N2 and O2 are solved separately to obtain the transport parameters of charged particles;

[0106] The transport parameters of charged particles are input into the electron transport equation to obtain the distribution of charged particles.

[0107] like Figure 2 As shown, in one specific embodiment, the needle-cylinder electrode gas-phase current fluid system includes a cylindrical channel with openings at both ends, a needle electrode and a cylinder electrode. The needle electrode and the cylinder electrode are coaxially fixed inside the cylindrical channel, and the needle electrode is located at the first end of the cylindrical channel, and the cylinder electrode is located at the second end of the cylindrical channel. The tip of the needle electrode points to the cylinder electrode, and a distance is left between the needle electrode and the cylinder electrode.

[0108] It should be noted that the needle electrode in this embodiment is a conical needle body, with its tip pointing toward the barrel electrode and its head facing away from the barrel electrode. In one specific embodiment, the diameter of the cylindrical channel is 40 mm, and the distance between the tip of the needle electrode and the inlet of the barrel electrode ranges from 10 to 40 mm.

[0109] The cylindrical channel is made of PMMA. Specifically, the needle electrode in this embodiment is coaxially fixed inside the cylindrical channel via a bracket.

[0110] In this embodiment, the needle electrode is connected to the positive terminal of a high-voltage power supply, while the tubular electrode is grounded. The needle electrode in this embodiment serves as an emitter electrode, placed on the central axis of the cylindrical channel and connected to the positive terminal of the high-voltage power supply. The tubular electrode serves as a collector electrode, also placed on the central axis of the cylindrical channel and connected to ground.

[0111] For the electric field boundary condition, the needle electrode is connected to a high voltage in The voltage can be set to the kV range as needed; the aluminum foil tube is grounded The pipe wall and the inlet and outlet boundaries are insulated, that is, set to zero charge In the flow field, the inlet boundary is set to the atmospheric pressure condition u = 0, p = p0, the outlet boundary is set to the pressure condition p = 0, and the other boundaries are set to the wall no-slip condition u = 0.

[0112] A multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model was constructed using the method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model proposed in the present invention, and the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model was solved. The solution results are shown in FIG. Figure 3 As shown. Figure 3 In the figure, (A) is the electron distribution result, (B) is the negative ion distribution result, (C) is the positive ion distribution result, (D) is the spatial charge density distribution result, (E) is the potential distribution result, (F) is the velocity distribution result, and (G) is the pressure distribution diagram.

[0113] from Figure 3 As can be seen from (A), the electron density is higher near the needle electrode and lower in the needle-tube gap. Due to secondary electron emission, the electron density increases to a certain extent near the aluminum foil tube electrode. Figure 3 As can be seen from (B), under the action of the electric field, negative ions are absorbed by the needle, and the density of negative ions in the needle-barrel gap is relatively low. Figure 3 As can be seen from (C), positive ions are most evenly distributed in the system and have the highest content. Figure 3 As can be seen in (D), the charge density is larger near the needle electrode and gradually decreases from the needle tip to the outside. Figure 3 As can be seen from (E), the potential is larger near the needle electrode and gradually decreases as it approaches the aluminum foil tube electrode. Figure 3 As can be seen from (F), the maximum velocity appears at the aluminum foil tube, and the gas velocity near the needle electrode is relatively low. Figure 3As can be seen from (G), the pressure around the needle-cylinder electrode is negative, with a minimum value of -2.23 Pa, and the pressure inside the channel aluminum foil tube is positive, with a maximum value of 10.4 Pa.

[0114] Experimental results were obtained for a needle-cylinder electrode gas-phase fluid system. Simulation results were obtained using a constructed multi-physics field coupled needle-cylinder electrode gas-phase fluid system model based on the same parameters as the experiment. The simulation results and experimental results are shown in Figure 4.

[0115] from Figure 4 It can be seen that the speed of the ion wind in the simulation results is very consistent with that in the experimental results.

[0116] In a second aspect, the present invention further proposes a system for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model, comprising:

[0117] A geometric model building module is used to build a geometric model of a needle-cylinder electrode gas-phase fluid system model;

[0118] A material property setting module is used to set the material properties of the geometric model of the needle-cylinder electrode gas-phase current fluid system model;

[0119] A meshing module is used to mesh the geometric model of the needle-cylinder electrode gas-phase current fluid system to obtain a mesh model of the needle-cylinder electrode gas-phase current fluid system;

[0120] A physics field addition module is used to add multiphysics fields to the mesh model of the needle-cylinder electrode gas-phase current fluid system to obtain a multiphysics field coupled needle-cylinder electrode gas-phase current fluid system model. The multiphysics fields include: electric field, gas ionization process, space charge density field, and flow field. The multiphysics field coupled needle-cylinder electrode gas-phase current fluid system model includes: electric field governing equations, electron transport equations, space charge transport equations, and flow field governing equations.

[0121] Boundary condition setting module, used to set the boundary conditions of the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model;

[0122] A solution module is used to solve the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model and obtain the solution result;

[0123] A judgment module is used to judge whether the solution results are converged; if so, a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is obtained;

[0124] The meshing module is also used to re-mesh the geometric model of the needle-cylinder electrode gas-phase current fluid system when the solution results have not converged until the solution results have converged.

[0125] In a third aspect, the present invention further proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model as described in any one of the foregoing.

[0126] In a fourth aspect, the present invention further proposes a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model described in any one of the first aspects.

[0127] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model, characterized in that: include: Construct the geometric model of the needle-cylinder electrode gas-phase electrofluid system model; Set the material properties of the geometry of the needle-cylinder electrode gas-phase electrofluidic system model; Meshing the geometric model of the needle-cylinder electrode gas-phase electric fluid system to obtain a mesh model of the needle-cylinder electrode gas-phase electric fluid system; Adding multiphysics to the mesh model of the needle-cylinder electrode gas-phase current fluid system creates a multiphysics-coupled needle-cylinder electrode gas-phase current fluid system model. The multiphysics includes the electric field, gas ionization process, space charge density field, and flow field. The multiphysics-coupled needle-cylinder electrode gas-phase current fluid system model includes the electric field governing equations, electron transport equations, space charge transport equations, and flow field governing equations. Set the boundary conditions for the multi-physics coupled needle-cylinder electrode gas-phase electrofluidic system model; The multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is solved to obtain solution results, and it is determined whether the solution results are converged; if so, the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is obtained; if not, the needle-cylinder electrode gas-phase current fluid system geometric model is re-meshed until the solution results are converged.

2. The method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model according to claim 1, characterized in that: The governing equation for the electric field is Where, is the Laplace operator, ε0 is the dielectric constant of air; is the electric potential; N p 、N m 、N e are the positive ion, negative ion and electron densities respectively, e is the elementary charge, and E is the electric field strength.

3. The method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model according to claim 1, characterized in that: The electron transport equation is Where N e is the electron density; is the Laplace operator, Γ e is the electron flux; R e is the reaction in which electrons participate; where R e Including R1~R20;D e is the electron diffusion rate, μ e is the electron mobility, E is the electric field intensity; Where R1 is e+N2→2e+N2 + ; R2 is e+O2→2e+O2 + ; R3 is e+O2→O - +O; R4 is e+2O2→O2 - +O2; R5 is N2 + +2e→N2+e; R6 is O4 + +e→2O2; R7 is O2 + +e→2O; R8 is N2 + +e+N2→2N2; R9 is O4 + +O2 - →3O2; R10 is O4 + +O2 - +N2→3O2+N2; R11 is O2 + +O2 - +N2→2O2+N2; R12 is N2 + +O2→O2 + +N2; R13 is 2N2+O2 + →N2O2 + +N2; R14 is N2O2 + +N2→O2 + +2N2; R15 is N2O2 + +O2→O4 + +N2; R16 is O2 + +O2+N2→O4 + +N2; R17 is O+O2+N2→O3+N2; R 18 is O - +O2 + →O+O2; R19 is N2 + +N2+O2→N4 + +O2;R20N4 + +O2→O2 + +2N2.

4. The method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model according to claim 1, characterized in that: The space charge transport equation is q = -e(N p -N m -N e );where q is space charge, e is elementary charge, N p 、N m 、N e are the densities of positive ions, negative ions, and electrons, respectively.

5. The method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model according to claim 1, characterized in that: The flow field governing equation is Where, is the Laplace operator, ρ is the air density, p is the air pressure, μ is the air dynamic viscosity coefficient, F e is the body force, F e =qE, q is the space charge, E is the electric field strength, and u is the velocity.

6. The method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model according to claim 1, characterized in that: The multi-physics coupled needle-cylinder electrode gas-phase current fluid system model is solved, and the solution results are obtained, including: Solve the electron transport equation to obtain the distribution of charged particles; According to the distribution of charged particles and the electric field control equation, the distribution of the electric field potential in space is obtained; According to the distribution of charged particles and the spatial charge transport equation, the spatial charge density distribution is obtained; According to the distribution of electric field potential in space, the distribution of charge density in space and the process control equation, the velocity and pressure are obtained; The distribution of charged particles, the distribution of electric field potential in space, the distribution of charge density in space and the combination of velocity and pressure are taken as the solution results.

7. The method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model according to claim 6, characterized in that: Solving the electron transport equations yields the distribution of charged particles, including: The collision cross section data of N2 and O2 in the air were obtained through the LXCat database; The collision cross section data of N2 and O2 are input into the Boltzmann equation respectively, and the electron energy distribution functions of N2 and O2 are obtained by solving them; The electron energy distribution functions of N2 and O2 are solved separately to obtain the transport parameters of charged particles; The transport parameters of charged particles are input into the electron transport equation to obtain the distribution of charged particles.

8. A system for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model, characterized in that: include: A geometric model building module is used to build a geometric model of a needle-cylinder electrode gas-phase fluid system model; A material property setting module is used to set the material properties of the geometric model of the needle-cylinder electrode gas-phase current fluid system model; A meshing module is used to mesh the geometric model of the needle-cylinder electrode gas-phase current fluid system to obtain a mesh model of the needle-cylinder electrode gas-phase current fluid system; A physics field addition module is used to add multiphysics fields to the mesh model of the needle-cylinder electrode gas-phase current fluid system to obtain a multiphysics field coupled needle-cylinder electrode gas-phase current fluid system model. The multiphysics fields include: electric field, gas ionization process, space charge density field, and flow field. The multiphysics field coupled needle-cylinder electrode gas-phase current fluid system model includes: electric field governing equations, electron transport equations, space charge transport equations, and flow field governing equations. Boundary condition setting module, used to set the boundary conditions of the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model; A solution module is used to solve the multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model and obtain the solution result; A judgment module is used to judge whether the solution results are converged; if so, a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model is obtained; The meshing module is also used to re-mesh the geometric model of the needle-cylinder electrode gas-phase current fluid system when the solution results have not converged until the solution results have converged.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model described in any one of claims 1 to 7 are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for constructing a multi-physics field coupled needle-cylinder electrode gas-phase current fluid system model described in any one of claims 1 to 7 are implemented.

Images