Photon transmission process analysis method and device for complex structure medium stream simulation, electronic equipment and storage medium

Abstract

The invention provides a photon transmission process analysis method and device for complex structure medium stream simulation, electronic equipment and a storage medium, and belongs to the technical field of high-voltage stream generation and emulation.The photon transmission process analysis method comprises the steps that the number of photons radiated by all subdivision nodes in a simulation area is calculated; randomly calculating absorption distances and directions of all photons, and determining a target absorption node; if the photons are not blocked by the solid medium, the photons are generated at the target absorption node to induce secondary electrons generated by oxygen molecule ionization; if the photons are blocked by the solid medium, carrying out collision ionization process treatment on the photons and the solid medium, and randomly generating the photons according to a secondary electron emission coefficient to induce secondary electrons generated by ionization of the solid medium; and obtaining secondary electron numbers of all the subdivision nodes in the simulation area, and updating the electron numbers of all the subdivision nodes. According to the method and the device, the accuracy of streamer development process simulation can be improved, and the randomness of streamer development process simulation can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage streamer generation and simulation, and in particular to a photon transmission process analysis method, device, electronic equipment and storage medium for streamer simulation of complex structure media. Background Art

[0002] Streamers are a common discharge phenomenon in gaseous and liquid media under high voltage. Firstly, power transmission and transformation equipment and pulsed power devices operate at high voltages, making streamer discharges highly susceptible to dielectric insulation under these conditions. Secondly, lightning leaders have a large streamer region, making studying streamer discharge mechanisms crucial for understanding lightning processes. Furthermore, streamer discharges are an effective means of forming low-temperature plasmas, with broad application prospects in waste gas treatment, ozone generation, waste liquid purification, and material modification. Therefore, uncovering the streamer development process and discharge mechanisms is of great value.

[0003] Numerical simulation is an effective method for analyzing streamer development. Common streamer simulation models include fluid models, particle models, and fluid-particle hybrid models. For example, CN115879385A discloses a method for simulating discharge streamers in insulating media that accounts for offset and bifurcation. The insulating medium is placed in an electric field environment, and the range of discharge streamer bifurcation points and the range of effective electron avalanches generated by each bifurcation are measured. The governing equations and boundary conditions for streamer simulation are constructed based on a fluid dynamics drift-diffusion model and a bipolar charge submodel. Model parameters modified based on electron avalanche development probability theory are introduced during the equation solution process, enabling a mathematical description and simulation of streamer offset and bifurcation phenomena. Ultimately, the electric field and charge distributions associated with discharge streamer development that account for offset and bifurcation are obtained. It is generally believed that during air discharge, photons emitted by excited nitrogen as it transitions to the ground state cause ionization of oxygen molecules, which is the primary mechanism driving positive streamer development. Therefore, this process must be considered in positive streamer simulations. Currently, most photon radiation-transmission calculation methods treat the streamer development region as an unobstructed space. It's important to note that in power transmission and transformation equipment and plasma applications, streamer development often occurs in regions where gas and solid media coexist. While streamers develop exclusively within the gaseous medium, the solid medium acts as a barrier to photon transmission. However, existing computational methods fail to account for this barrier, resulting in inaccurate simulations of streamer development. Furthermore, existing methods typically transform the integral model of photon radiation and transmission into a set of Helmholtz differential equations for solution. This approach ignores the random nature of photons and, therefore, cannot simulate the randomness of streamer development. Summary of the Invention

[0004] In response to the above problems, the present invention provides a photon transmission process analysis method, device, electronic device and storage medium for streamer simulation of complex structure media, which improves the accuracy of streamer development process simulation and realizes the randomness of streamer development process simulation.

[0005] The present invention provides a method for analyzing a photon transmission process for streamer simulation of a complex structure medium, comprising: Based on the photon radiation model of gas ionization, the number of photons radiated by all the nodes in the simulation area is calculated; Randomly calculate the absorption distance and direction of all photons and determine the target absorption nodes of all photons; Determine whether all photons are blocked by solid media on the transmission path. If the photons are not blocked by solid media, generate secondary electrons at the target absorption node by photon-induced ionization of oxygen molecules. If the photons are blocked by solid media, perform a collision ionization process between the photons and the solid media, and randomly generate secondary electrons based on the secondary electron emission coefficient. Obtain the number of secondary electrons generated by photon-induced ionization at all subdivision nodes in the simulation area, and update the number of electrons at all subdivision nodes after photon-induced ionization.

[0006] As an improvement of the present invention, the photon radiation model based on gas ionization calculates the number of photons radiated by all subdivided nodes in the simulation area, including using discrete distribution to generate random numbers to obtain the number of photons radiated by all subdivided nodes.

[0007] As an improvement of the present invention, the formula for the discrete distribution is:

[0008] Where, is the base of natural logarithms, For the The average number of photons radiated by a split node, for of Power, The number of photons emitted is The probability of in, The calculation is done using the following formula:

[0009] Where, is the air pressure, To quench the pressure, is the proportionality coefficient, is the electron impact ionization coefficient, is the electron mobility, For the The electric field strength of each segmentation node, For the The electron density of the mesh node, is the area or volume of a single mesh, is the simulation step size.

[0010] As an improvement of the present invention, the randomly calculating the absorption distance and direction of all photons and determining the target absorption nodes of all photons includes: Generate random numbers for photon frequencies; Calculate the absorption distance of photons based on random numbers of photon frequencies; generating a first random number and a second random number as an azimuth angle and a zenith angle of photon transmission; The target absorption node of the photon is determined according to the absorption distance of the photon and the azimuth and zenith angle of the photon transmission.

[0011] As an improvement of the present invention, the following formula is used to generate a random number of photon frequency:

[0012] Where, and are the minimum and maximum values ​​of the photon frequency, is a uniform random number in the range of 0-1; The absorption distance of photons is calculated using the following formula:

[0013] Where, and are the minimum and maximum oxygen absorption coefficients, respectively. is a uniform random number in the range of 0-1; The following formula is used to generate the first random number as the azimuth angle of photon transmission:

[0014] Where, is the first random number, is a uniform random number in the range of 0-1; The following formula is used to generate a second random number as the zenith angle of photon transmission:

[0015] Where, is the second random number, is a uniform random number in the range of 0-1; Assuming that photons travel in a straight line, the target absorption node of the photons can be determined using the following formula based on the absorption distance and direction of the photons:

[0016]

[0017]

[0018] Where, 、 、 are the target absorption nodes of the photons, axis, Axis and Axis coordinates, 、 、 are the initial nodes where the photons are located. axis, Axis and Axis coordinates, When photons are transmitted Axis displacement, When photons are transmitted Axis displacement, When photons are transmitted Axis displacement.

[0019] As an improvement of the present invention, the determining whether all photons are blocked by solid media on the transmission path includes: The step length of the transmission along the straight line formed by the initial node and the target absorbing node is set to , set the step node The axis coordinates are = + , The axis coordinates are = + , The axis coordinates are = + ,in is the number of steps forward; Determine whether the stepping node is located inside the solid medium. If the stepping node is located outside the solid medium, the forward step is increased. Add 1, repeat the above steps, and determine whether the step node reaches the target absorption node. If the step node reaches the target absorption node, the above iterative process is terminated, indicating that the photon is not blocked by the solid medium on the transmission path; if the step node is located inside the solid medium, the above iterative process is terminated, indicating that the photon is blocked by the solid medium on the transmission path, and the node closest to the step node on the gas side is set as the secondary electron emission node.

[0020] As an improvement of the present invention, the random generation of secondary electrons produced by photon-induced ionization of solid media based on the secondary electron emission coefficient includes generating a uniformly distributed random number in the range of 0-1. If the random number is less than the secondary electron emission coefficient, secondary electrons produced by photon-induced ionization of solid media are generated in the secondary electron emission node; if the random number is greater than the secondary electron emission coefficient, no operation is performed.

[0021] The present invention provides a device for analyzing photon transmission processes for streamer simulation of complex structure media, comprising: The first processing module is used to calculate the number of photons radiated by all the partitioned nodes in the simulation area based on the photon radiation model of gas ionization; The second processing module is used to randomly calculate the absorption distance and direction of all photons and determine the target absorption nodes of all photons; a third processing module, configured to determine whether all photons are blocked by solid media in the transmission path; if the photons are not blocked by the solid media, generating secondary electrons at the target absorption node by photon-induced ionization of oxygen molecules; and if the photons are blocked by the solid media, performing a collision ionization process between the photons and the solid media, randomly generating secondary electrons by photon-induced ionization of the solid media according to the secondary electron emission coefficient; The fourth processing module is used to obtain the number of secondary electrons generated by photon-induced ionization of all subdivided nodes in the simulation area, and update the number of electrons in all subdivided nodes after photon-induced ionization.

[0022] The present invention provides an electronic device comprising a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above-mentioned photon transmission process analysis method for complex structure medium flow simulation.

[0023] The present invention provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned photon transmission process analysis method for complex structure medium streamer simulation.

[0024] The present invention provides a method, device, electronic device, and storage medium for analyzing photon transmission processes for streamer simulation of complex structure media, which can achieve the following beneficial effects: 1. The present invention's photon transmission process analysis method for streamer simulation in complex structure media determines whether the photon transmission path passes through a solid medium and takes into account the solid medium's blocking effect on photon transmission and the process of generating secondary electrons when photons collide with the solid medium. This method addresses the problem of inaccurate streamer development caused by ignoring the blocking effect of the solid medium in existing technologies. It can improve the accuracy of streamer simulation in areas blocked by solid media. 2. The present invention's photon transmission process analysis method for streamer simulation in complex structures utilizes a discrete random method to analyze the photon radiation, transmission, and secondary electron emission processes. This method fully considers the randomness of the photon radiation, transmission, and absorption processes, thereby resolving the problem of prior art in being unable to simulate the randomness of streamer development. This method can more accurately simulate the randomness of electron density, development direction, and other aspects of streamer development. 3. The photon transmission process analysis method for complex structure medium streamer simulation of the present invention adopts a photon transmission path stepping method. On the one hand, it can quickly determine whether the photon is blocked by the solid medium. On the other hand, it can obtain the secondary electron emission node, and then simulate the process of photon-induced ionization of the solid medium to produce secondary electrons, thereby improving the accuracy of the streamer development process simulation. 4. The photon transmission process analysis method for complex structure medium stream simulation of the present invention can be combined with the fluid model, particle model and fluid-particle mixed model of stream simulation, and has the advantages of wide applicability and simple calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of a method for analyzing a photon transmission process for streamer simulation of a complex structure medium according to an embodiment of the present invention.

[0026] Figure 2 It is a schematic diagram of the photon transmission path of the photon transmission process analysis method for complex structure medium streamer simulation according to an embodiment of the present invention.

[0027] Figure 3 It is a flow chart of the simulation of complex structure medium flow.

[0028] Figure 4 This is an electron density evolution diagram of Example 1 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0029] Figure 5 This is a photon density evolution diagram of Example 1 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0030] Figure 6 This is an electron density evolution diagram of Comparative Example 1 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0031] Figure 7 This is a photon density evolution diagram of Comparative Example 1 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0032] Figure 8This is an electron density evolution diagram of Example 2 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0033] Figure 9 This is an electron density evolution diagram of Comparative Example 2 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0034] Figure 10 This is an electron density evolution diagram of Example 3 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0035] Figure 11 This is an electron density evolution diagram of Comparative Example 3 obtained by simulating the photon transmission process analysis method for complex structure medium streamer simulation based on an embodiment of the present invention.

[0036] Figure 12 It is a structural schematic diagram of a photon transmission process analysis device for stream injection simulation of complex structure media according to the second embodiment of the present invention.

[0037] Explanation of reference numerals: 10, first processing module; 20, second processing module; 30, third processing module; 40, fourth processing module. DETAILED DESCRIPTION

[0038] The following is a combination of specific embodiments and appendix Figure 1-12 The invention is described in detail so that those skilled in the art can more fully understand the purpose, features and effects of the invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. In the event that the definition of a term in the present invention conflicts with the meaning commonly understood by those skilled in the art to which the invention belongs, the definition in the present invention shall prevail.

[0040] The present invention provides a photon transmission process analysis method, device, electronic device and storage medium for complex structure medium streamer simulation. On the one hand, the blocking effect of solid medium on photon transmission is taken into account to solve the problem of inaccurate simulation of streamer development process caused by ignoring the blocking effect of solid medium in the prior art. On the other hand, a discrete random method is used to analyze the photon radiation, transmission and secondary electron emission process, fully considering the randomness of the photon radiation, transmission and absorption process, so as to solve the problem of the inability to simulate the random phenomenon in the streamer development process in the prior art.

[0041] Example 1 As a specific embodiment of the present invention, this embodiment provides a photon transmission process analysis method for complex structure medium stream injection simulation, referring to Figure 1 、 Figure 2 , the specific steps are as follows: S100, based on the photon radiation model of gas ionization, calculate the number of photons radiated by all the subdivided nodes in the simulation area; S200, randomly calculating the absorption distance and direction of all photons, and determining the target absorption nodes of all photons; S300, determining whether all photons are blocked by solid media in the transmission path; if the photons are not blocked by the solid media, generating secondary electrons at the target absorption node by photon-induced ionization of oxygen molecules; if the photons are blocked by the solid media, performing a collision ionization process between the photons and the solid media, and randomly generating secondary electrons based on the secondary electron emission coefficient by photon-induced ionization of the solid media; S400, obtaining the number of secondary electrons generated by photon-induced ionization in all the subdivided nodes in the simulation area, and updating the number of electrons in all the subdivided nodes after photon-induced ionization.

[0042] Furthermore, in S100 , the simulation area is generally a rectangle in a two-dimensional space and a cuboid in a three-dimensional space.

[0043] Optionally, when meshing the simulation area, a vertical cross meshing method, a triangular meshing method, or an adaptive density meshing method may be used. The photon transmission process analysis method for complex structure medium stream injection simulation of this embodiment performs calculations on the nodes of the mesh.

[0044] Specifically, the calculating the number of photons radiated by all the split nodes in the simulation area includes obtaining the number of photons radiated by all the split nodes by generating random numbers using a discrete distribution. Each split node generates a number of photons.

[0045] Preferably, the following discrete distribution formula is adopted:

[0046] Where, is the base of natural logarithms, For the The average number of photons radiated by a split node, for of Power, The number of photons emitted is This formula is used to represent the photon radiation model based on gas ionization.

[0047] Furthermore, The calculation is done using the following formula:

[0048] Where, is the air pressure, To quench the pressure, is the proportionality coefficient, is the electron impact ionization coefficient, is the electron mobility, For the The electric field strength of each segmentation node, For the The electron density of the mesh node, is the area or volume of a single mesh, is the simulation step size.

[0049] The photons are primarily emitted when excited nitrogen molecules de-excite to their ground state, ionizing oxygen molecules in the air. The number of photons emitted is closely related to the electron impact ionization coefficient, electron density, electric field strength, and electron mobility.

[0050] The analysis of the photon transmission process is part of the streamer simulation. The complete streamer simulation includes solving the Poisson equation to calculate the electric field distribution, solving the electron and ion motion equations, solving the surface charge accumulation model, and analyzing the photon transmission process. Figure 3 shown.

[0051] The electron density and electric field strength are obtained by solving the streamer simulation model. Optionally, the streamer simulation model can be a fluid model, a particle model, or a fluid-particle mixed model. The following uses the fluid model and the fluid-particle mixed model as examples for explanation.

[0052] For the fluid model, the movement of electrons and ions is described by the drift-diffusion equation, which is:

[0053]

[0054]

[0055] Where, is the electron density during the simulation, and are the densities of positive and negative ions in the simulation process, ± represents the polarity of the ions, is the simulation time, is the electron mobility, is the electric field strength vector, is the electron diffusion coefficient, 、 、 、 They are the electron impact ionization source term, electron attachment source term, photoionization source term and solid medium surface secondary electron emission source term, and are the mobility of positive and negative ions, respectively. is the mathematical symbol for partial derivative, is the gradient symbol, is the divergence operator.

[0056] Furthermore, the electric field strength is obtained by solving the Poisson equation:

[0057]

[0058] Where, is the dielectric constant, is the electric potential, is the space charge density.

[0059] The surface charge accumulation model is expressed as follows:

[0060] Where, is the surface charge density of the solid medium, is the charge flux on the surface of the solid medium.

[0061] For the fluid-particle mixing model, the motion process of electrons is described by the particle motion equation, and the motion process of ions is described by the drift-diffusion equation, which is:

[0062]

[0063]

[0064] Where, is the electron's position vector, is the simulation step size, for The electron displacement in time, is the electron migration velocity vector, is a standard normal distribution vector.

[0065] Furthermore, the electric field strength is obtained by solving the Poisson equation:

[0066]

[0067] The surface charge accumulation model is expressed as follows:

[0068] By iteratively solving the equations of motion for electrons and ions, Poisson's equation, and the surface charge accumulation model, the electron density and electric field strength can be calculated.

[0069] Furthermore, the electron mobility, diffusion coefficient, electron impact ionization coefficient, electron attachment coefficient, and reaction coefficient were calculated using the Phelps collision cross section dataset using the BOLSIG+ software.

[0070] Furthermore, in S200, the randomly calculating the absorption distance and direction of all photons and determining the target absorption nodes of all photons includes: Generate random numbers for photon frequencies; Calculate the absorption distance of photons based on random numbers of photon frequencies; generating a first random number and a second random number as an azimuth angle and a zenith angle of photon transmission; The target absorption node of the photon is determined according to the absorption distance of the photon and the azimuth and zenith angle of the photon transmission.

[0071] Optionally, use the following formula to generate a random number for the photon frequency:

[0072] Where, and are the minimum and maximum values ​​of the photon frequency, A uniform random number in the range of 0-1.

[0073] In one example, the minimum value of the photon frequency and maximum value 5.25cm respectively -1 and 300cm -1 .

[0074] The frequency of photons has a certain degree of randomness, and this phenomenon is simulated by generating random frequencies within the photon frequency range.

[0075] The absorption distance of photons is calculated using the following formula:

[0076] Where, and are the minimum and maximum oxygen absorption coefficients, respectively. A uniform random number in the range of 0-1.

[0077] In one example, the oxygen absorption coefficient minimum and the maximum oxygen absorption coefficient are 2.925×1015 Hz and 3.059×10 15 Hz.

[0078] The absorption distance of photons is related to the frequency of photons. The above formula is used to calculate the absorption distance of photons of different frequencies.

[0079] The following formula is used to generate the first random number as the azimuth angle of photon transmission:

[0080] Where, is the first random number, A uniform random number in the range of 0-1.

[0081] The following formula is used to generate a second random number as the zenith angle of photon transmission:

[0082] Where, is the second random number, A uniform random number in the range of 0-1.

[0083] The radiation process of photons is regarded as isotropic, that is, the probability of transmission in different directions is the same. Therefore, the randomness of the transmission direction is simulated by generating random angles.

[0084] Assuming that photons travel in a straight line, the target absorption node of the photons can be determined using the following formula based on the absorption distance and direction of the photons:

[0085]

[0086]

[0087] Where, 、 、 are the target absorption nodes of the photons, axis, Axis and Axis coordinates, 、 、 are the initial nodes where the photons are located. axis, Axis and Axis coordinates, When photons are transmitted Axis displacement, When photons are transmitted Axis displacement, When photons are transmitted Axis displacement.

[0088] Furthermore, in S300, determining whether all photons are blocked by solid media on the transmission path includes: The step length of the transmission along the straight line formed by the initial node and the target absorbing node is set to , set the step node The axis coordinates are = + , The axis coordinates are = + , The axis coordinates are = + ,in is the number of steps forward; Determine whether the stepping node is located inside the solid medium. If the stepping node is located outside the solid medium, the forward step is increased. Add 1, repeat the above steps, and determine whether the stepping node reaches the target absorption node. If the stepping node reaches the target absorption node, the above iterative process is terminated, indicating that the photon is not blocked by the solid medium on the transmission path; if the stepping node is located inside the solid medium, the above iterative process is terminated, indicating that the photon is blocked by the solid medium on the transmission path.

[0089] In this embodiment, the transmission path of the photon is regarded as a straight line, that is, a straight line formed by the initial node and the target absorption node. The mesh size should not be larger than the simulation area.

[0090] If the photon is not blocked by a solid medium during its transmission path, it is considered that the photon can be successfully transmitted to the target absorption node. After the photon is transmitted to the target absorption node, it will cause the oxygen molecules in the target absorption node to ionize, thereby generating secondary electrons. Secondary electrons generated by the photon-induced ionization of oxygen molecules are generated at the target absorption node.

[0091] The emitted photons propagate in all directions before landing on a target absorption node, ionizing the oxygen molecules there and generating secondary electrons. If a photon lands on a target absorption node, the oxygen molecules there are ionized, and the number of secondary electrons increases by one.

[0092] Solid dielectrics play two roles in the photon transmission and absorption process. First, streamer discharge is generally believed to occur on the gas side, but most solid dielectrics are opaque, and the photons emitted during the discharge process may be blocked by the solid dielectric during transmission, at which point they will be absorbed by the solid dielectric. Second, if the photons are blocked by the solid dielectric during transmission, they will trigger photoelectron emission when they collide with the solid dielectric, generating secondary electrons that participate in the streamer discharge process on the gas side. To summarize, it is necessary to determine whether the photons are blocked by the solid dielectric during transmission. If so, the collision ionization process between the photons and the solid dielectric is processed, and secondary electrons generated by photon-induced ionization of the solid dielectric are randomly generated based on the secondary electron emission coefficient.

[0093] If a photon is blocked by a solid medium during its transmission path, the photon-solid medium collision ionization process is performed. After the photon collides with the solid medium, the secondary electrons generated fall on the node closest to the stepping node on the gas side. This node on the gas side closest to the stepping node is set as the secondary electron emission node, and the loop exits. If it is determined that the photon transmission path will encounter a solid medium, the photon will be blocked by the solid medium and will inevitably fail to transmit to the target absorption node, so there is no need to continue the loop.

[0094] The random generation of secondary electrons generated by photon-induced ionization of solid media based on the secondary electron emission coefficient includes generating a uniformly distributed random number in the range of 0-1. If the random number is less than the secondary electron emission coefficient, secondary electrons generated by photon-induced ionization of solid media are generated in the secondary electron emission node; if the random number is greater than the secondary electron emission coefficient, no operation is performed.

[0095] The secondary electron emission coefficient is usually much smaller than 1, meaning that multiple photons collide with a solid medium to produce one secondary electron. Furthermore, the process of photons colliding with a solid medium to produce secondary electron emission is random, and this phenomenon can be better simulated by generating random numbers.

[0096] By substituting the number of electrons at all the nodes after photon-induced ionization into the simulation model describing the development of the streamer, the electric field intensity and electron density of the next simulation step can be obtained.

[0097] The development of positive streamers is primarily driven by photon radiation-ionization. This requires calculating the number of secondary electrons generated by photon-induced ionization at all nodes within the simulation domain. This number is then added to the existing electron count to obtain the total electron count for all nodes. This number is then substituted into the streamer simulation model to simulate the streamer's development. The final electron count is the sum of the existing electron count at some nodes and the secondary electron count generated by photon-induced ionization.

[0098] The photon transmission process analysis method for complex structure medium streamer simulation of this embodiment determines whether the photon transmission path passes through a solid medium, and takes into account the blocking effect of the solid medium on photon transmission and the process of photons colliding with the solid medium to produce secondary electrons, so as to solve the problem of inaccurate simulation of the streamer development process caused by ignoring the blocking effect of the solid medium in the prior art; it uses a discrete random method to analyze the photon radiation, transmission and secondary electron emission process, and fully considers the randomness of the photon radiation, transmission and absorption process, so as to solve the problem of the prior art that it cannot simulate the random phenomenon in the streamer development process.

[0099] In addition, the photon transmission process analysis method for complex structure medium flow simulation of this embodiment can be combined with the fluid model, particle model and fluid-particle mixed model of flow simulation, and has the advantages of wide applicability and simple calculation.

[0100] The following is further described by specific examples 1-3 and comparative examples 1-3.

[0101] Example 1 A porous solid medium was used to simulate a complex structure medium and perform streamer simulation. The size of the simulation area was 1 mm × 0.5 mm. The length and width of the porous solid medium were 1 mm and 0.25 mm, respectively. The gas medium in the upper half of the model was air, and the medium in the air gap inside the porous solid medium was also air. The rod electrode was 0.05 mm long and 0.01 mm in diameter. The electron mobility, diffusion coefficient, electron impact ionization coefficient, electron attachment coefficient, and reaction coefficient were calculated using the Phelps collision cross section data set using the BOLSIG+ software; the ion mobility was set to 2×10 -4 m 2 (Vs) -1 , the diffusion coefficient is set to 0. The relative dielectric constants of the gas and solid medium are set to 1 and 4 respectively, and the secondary electron emission coefficient caused by photon collision on the surface of the solid medium is 0. The boundary conditions of the rod electrode and the left boundary are set to 15kV potential, the right boundary condition is set to ground, and the upper and lower boundary conditions are set to Neumann boundary conditions. The initial conditions of the simulation are: the radius of the rod electrode head is 7 Initial electrons, totaling 1000, were placed in a Gaussian distribution within a circular region. The streamer development process was simulated using a fluid-particle mixing model. The photon transmission process took into account the blocking effect of the solid medium on photons, but ignored the secondary electron emission process when photons collided with the solid medium.

[0102] The electron density distribution under different simulation times is obtained as follows Figure 4 As shown, the photon density distribution is Figure 5As shown in the figure, the streamer develops from the rod electrode because the electric field intensity is highest at the tip of the rod electrode and the collision ionization reaction is intense in this region. Subsequently, the streamer generated by the rod electrode develops toward the surface of the solid medium, indicating that the solid medium has a certain attraction to the streamer, and the streamer further develops along the surface of the solid medium. During the streamer development, some of the radiated photons will enter the interior of the pores. Due to the combined effect of the high electric field intensity inside the pores, discharge processes will also form in some pores. However, because the photons are blocked by the pore wall when transmitting into the pore interior, the overall discharge in the pore is weak, and the streamer mainly develops along the surface of the solid medium, causing breakdown.

[0103] Comparative Example 1 The streamer development process was simulated using the fluid particle mixing model using the same geometric model, simulation parameters, and initial conditions as Example 1. In Comparative Example 1, the photon transmission process ignored the blocking effect of the solid medium on photons, that is, photons can be transmitted directly through the solid medium.

[0104] The electron density distribution under different simulation times is obtained as follows Figure 6 As shown, the photon density distribution is Figure 7 As shown in the figure, it can be seen that since Comparative Example 1 ignores the blocking effect of the solid medium on photon transmission, that is, the photons can directly pass through the pore wall to the inside of the pore, the photon density inside the pore in Comparative Example 1 is Obviously higher than Example 1. Analysis of electron density It can be seen that the higher photon density within the air gap in Comparative Example 1 enhances photoionization within the pore, resulting in a higher discharge intensity and earlier discharge initiation within the pore. For example, Comparative Example 1 forms a clear discharge within the pore at 0.238 ns, while Example 1 only begins to form a discharge within the pore at 0.304 ns. The above analysis shows that because Comparative Example 1 ignores the blocking effect of the solid medium on the photon transmission process, the simulated streamer development process, especially the discharge characteristics within the pore, are significantly different. Therefore, the blocking effect of the solid medium on the photon transmission process needs to be considered when simulating streamers in complex solid media.

[0105] Example 2 The streamer development process was simulated using the same geometric model, simulation parameters, and initial conditions as in Example 1, using a fluid-particle mixing model. The photon transmission process took into account the blocking effect of the solid medium on photons and the secondary electron emission process when photons collided with the solid medium. The secondary electron emission coefficient when photons collided with the solid medium surface was set to 0.1.

[0106] The electron density distribution under different simulation times is obtained as follows Figure 8As shown in the figure, the discharge intensity within the pore is significantly enhanced after considering the secondary electron emission process caused by photons impacting the solid medium. This is because photons impacting the pore wall generate more secondary electrons, which promotes discharge. The discharge process at this time can be roughly described as follows: after the rod electrode discharge initiates, the streamer will propagate toward the solid medium and develop along the surface of the solid medium. Due to the high electric field intensity within the pore, discharge also forms within the pore at 0.221ns. Under the influence of secondary electrons generated by photons impacting the pore wall, the discharge within the pore is relatively strong. After developing to a certain extent, the discharge within the pore reaches a saturated state and will develop outside the pore, merging with the streamer along the surface of the solid medium, causing breakdown.

[0107] Comparative Example 2 The streamer development process was simulated using the same geometric model, simulation parameters, and initial conditions as in Example 1, using a fluid-particle mixing model. The blocking effect of the solid medium on photons was ignored during photon transmission, but secondary electron emission from photons impacting the solid medium was considered. The secondary electron emission coefficient for photons impacting the solid medium surface was set to 0.1.

[0108] The electron density distribution under different simulation times is obtained as follows Figure 9 As shown. It can be seen from the figure that compared with Example 2, the discharge intensity in the pores of Comparative Example 2 is weaker. The main reason is that: both Example 2 and Comparative Example 2 consider the secondary electron emission process of photons colliding with solid media, and Comparative Example 2 ignores the blocking effect of the solid medium on photons. Therefore, the photons in the pores of Comparative Example 2 will radiate to the external space, reducing the number of photons in the pores, that is, weakening the secondary electron emission effect of photons colliding with the solid medium, and weakening the discharge intensity. It can be seen that Comparative Example 2 and Example 2 present different discharge characteristics, which further illustrates that the blocking effect of the solid medium on the photon transmission process needs to be considered when simulating complex solid medium streamers.

[0109] Example 3 A porous solid medium was used to simulate a complex structure medium and perform streamer simulation. The size of the simulation area was 1 mm × 0.5 mm. The length and width of the porous solid medium were 1 mm and 0.25 mm, respectively. The gas medium in the upper half of the model was air, and the medium in the air gap inside the porous solid medium was also air. The rod electrode was 0.05 mm long and 0.01 mm in diameter. The electron mobility, diffusion coefficient, electron impact ionization coefficient, electron attachment coefficient, and reaction coefficient were calculated using the Phelps collision cross section data set using the BOLSIG+ software; the ion mobility was set to 2×10 -4 m 2 (Vs) -1, the diffusion coefficient is set to 0. The relative dielectric constants of the gas and solid medium are set to 1 and 4 respectively, and the secondary electron emission coefficient caused by photon collisions on the surface of the solid medium is 0.1. The boundary conditions of the rod electrode and the left boundary are set to 15kV potential, the right boundary condition is set to ground, and the upper and lower boundary conditions are set to Neumann boundary conditions. The initial conditions of the simulation are: set the background electron density to 10 10 / m 3 , the radius of the rod electrode head is 7 The initial electrons are placed in the circular area with an electron density of 10 14 / m 3 , placed according to Gaussian distribution. The streamer development process is simulated using a fluid model. The photon transmission process takes into account the blocking effect of the solid medium on photons and the secondary electron emission process when photons collide with the solid medium.

[0110] The electron density distribution under different simulation times is obtained as follows Figure 10 As shown in the figure, since background electrons are set in the entire gas medium area, the discharge tends to start from the inside of the air gap. The discharge inside the pore merges with the surface discharge excited by the rod electrode, causing breakdown.

[0111] Comparative Example 3 The streamer development process was simulated using a fluid model, using the same geometric model, simulation parameters, and initial conditions as Example 3. The blocking effect of the solid medium on photons was ignored during photon transmission, but secondary electron emission from photons impacting the solid medium was considered. The secondary electron emission coefficient for photons impacting the solid medium surface was set to 0.1.

[0112] The electron density distribution under different simulation times is obtained as follows Figure 11 As shown in the figure, the discharge intensity inside and outside the pores of Comparative Example 3 is greater than that of Example 3. This is because Comparative Example 3 ignores the blocking effect of the solid medium on photons. Photons from both the air domain and the pore interior can be transmitted to each other, mutually reinforcing each other and thus increasing the discharge intensity in both regions. It can be seen that Comparative Example 3 and Example 3 exhibit different discharge characteristics, further demonstrating that the blocking effect of the solid medium on the photon transmission process must be considered when simulating complex solid medium streamers.

[0113] Example 2 As a specific embodiment of the present invention, this embodiment provides a photon transmission process analysis device for complex structure medium flow simulation, referring to Figure 12 ,include: The first processing module 10 is used to calculate the number of photons radiated by all the partitioned nodes in the simulation area based on the photon radiation model of gas ionization; The second processing module 20 is used to randomly calculate the absorption distance and direction of all photons and determine the target absorption nodes of all photons; The third processing module 30 is configured to determine whether all photons are blocked by solid media in the transmission path. If the photons are not blocked by the solid media, secondary electrons are generated at the target absorption node due to the photon-induced ionization of oxygen molecules. If the photons are blocked by the solid media, a collision ionization process between the photons and the solid media is performed, and secondary electrons generated by the photon-induced ionization of the solid media are randomly generated according to the secondary electron emission coefficient. The fourth processing module 40 is used to obtain the number of secondary electrons generated by photon-induced ionization of all the subdivided nodes in the simulation area, and update the number of electrons in all the subdivided nodes after photon-induced ionization.

[0114] Example 3 As a specific embodiment of the present invention, this embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the photon transmission process analysis method for complex structure medium streamer simulation in embodiment 1: S100, based on the photon radiation model of gas ionization, calculate the number of photons radiated by all the subdivided nodes in the simulation area; S200, randomly calculating the absorption distance and direction of all photons, and determining the target absorption nodes of all photons; S300, determining whether all photons are blocked by solid media in the transmission path; if the photons are not blocked by the solid media, generating secondary electrons at the target absorption node by photon-induced ionization of oxygen molecules; if the photons are blocked by the solid media, performing a collision ionization process between the photons and the solid media, and randomly generating secondary electrons based on the secondary electron emission coefficient by photon-induced ionization of the solid media; S400, obtaining the number of secondary electrons generated by photon-induced ionization in all the subdivided nodes in the simulation area, and updating the number of electrons in all the subdivided nodes after photon-induced ionization.

[0115] Example 4 As a specific embodiment of the present invention, this embodiment provides a storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the photon transmission process analysis method for complex structure medium streamer simulation of embodiment 1 are implemented: S100, based on the photon radiation model of gas ionization, calculate the number of photons radiated by all the subdivided nodes in the simulation area; S200, randomly calculating the absorption distance and direction of all photons, and determining the target absorption nodes of all photons; S300, determining whether all photons are blocked by solid media in the transmission path; if the photons are not blocked by the solid media, generating secondary electrons at the target absorption node by photon-induced ionization of oxygen molecules; if the photons are blocked by the solid media, performing a collision ionization process between the photons and the solid media, and randomly generating secondary electrons based on the secondary electron emission coefficient by photon-induced ionization of the solid media; S400, obtaining the number of secondary electrons generated by photon-induced ionization in all the subdivided nodes in the simulation area, and updating the number of electrons in all the subdivided nodes after photon-induced ionization.

[0116] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent variation based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A photon transmission process analysis method for streamer simulation of complex structure media, characterized in that: The method comprises: Based on the photon radiation model of gas ionization, the number of photons radiated by all the nodes in the simulation area is calculated; Randomly calculate the absorption distance and direction of all photons and determine the target absorption nodes of all photons; Determine whether all photons are blocked by solid media on the transmission path. If the photons are not blocked by solid media, generate secondary electrons at the target absorption node by photon-induced ionization of oxygen molecules. If the photons are blocked by solid media, perform a collision ionization process between the photons and the solid media, and randomly generate secondary electrons based on the secondary electron emission coefficient. Obtain the number of secondary electrons generated by photon-induced ionization at all subdivision nodes in the simulation area, and update the number of electrons at all subdivision nodes after photon-induced ionization.

2. The photon transmission process analysis method for complex structure medium streamer simulation according to claim 1 is characterized in that: The gas ionization-based photon radiation model calculates the number of photons radiated by all the subdivided nodes in the simulation area, including using discrete distribution to generate random numbers to obtain the number of photons radiated by all the subdivided nodes.

3. The photon transmission process analysis method for complex structure medium streamer simulation according to claim 2 is characterized in that: The formula for the discrete distribution is: Where, is the base of natural logarithms, For the The average number of photons radiated by a split node, for of Power, The number of photons emitted is The probability of in, The calculation is done using the following formula: Where, is the air pressure, To quench the pressure, is the proportionality coefficient, is the electron impact ionization coefficient, is the electron mobility, For the The electric field strength of each segmentation node, For the The electron density of the mesh node, is the area or volume of a single mesh, is the simulation step size.

4. The photon transmission process analysis method for complex structure medium streamer simulation according to claim 1 is characterized in that: The randomly calculating the absorption distance and direction of all photons and determining the target absorption nodes of all photons includes: Generate random numbers for photon frequencies; Calculate the absorption distance of photons based on random numbers of photon frequencies; generating a first random number and a second random number as an azimuth angle and a zenith angle of photon transmission; The target absorption node of the photon is determined according to the absorption distance of the photon and the azimuth and zenith angle of the photon transmission.

5. The photon transmission process analysis method for complex structure medium streamer simulation according to claim 4 is characterized in that: The following formula is used to generate random numbers of photon frequencies: Where, and are the minimum and maximum values ​​of the photon frequency, is a uniform random number in the range of 0-1; The absorption distance of photons is calculated using the following formula: Where, and are the minimum and maximum oxygen absorption coefficients, respectively. is a uniform random number in the range of 0-1; The following formula is used to generate the first random number as the azimuth angle of photon transmission: Where, is the first random number, is a uniform random number in the range of 0-1; The following formula is used to generate a second random number as the zenith angle of photon transmission: Where, is the second random number, is a uniform random number in the range of 0-1; Assuming that photons travel in a straight line, the target absorption node of the photons can be determined using the following formula based on the absorption distance and direction of the photons: Where, 、 、 are the target absorption nodes of the photons, axis, Axis and Axis coordinates, 、 、 are the initial nodes where the photons are located. axis, Axis and Axis coordinates, When photons are transmitted Axis displacement, When photons are transmitted Axis displacement, When photons are transmitted Axis displacement.

6. The photon transmission process analysis method for complex structure medium streamer simulation according to claim 5 is characterized in that: The determining whether all photons are blocked by solid media on the transmission path includes: The step length of the transmission along the straight line formed by the initial node and the target absorbing node is set to , set the step node The axis coordinates are = + , The axis coordinates are = + , The axis coordinates are = + ,in is the number of steps forward; Determine whether the stepping node is located inside the solid medium. If the stepping node is located outside the solid medium, the forward step is increased. Add 1, repeat the above steps, and determine whether the step node reaches the target absorption node. If the step node reaches the target absorption node, the above iterative process is terminated, indicating that the photon is not blocked by the solid medium on the transmission path; if the step node is located inside the solid medium, the above iterative process is terminated, indicating that the photon is blocked by the solid medium on the transmission path, and the node closest to the step node on the gas side is set as the secondary electron emission node.

7. The photon transmission process analysis method for complex structure medium streamer simulation according to claim 1 is characterized in that: The random generation of secondary electrons generated by photon-induced ionization of solid media based on the secondary electron emission coefficient includes generating a uniformly distributed random number in the range of 0-1. If the random number is less than the secondary electron emission coefficient, secondary electrons generated by photon-induced ionization of solid media are generated in the secondary electron emission node; if the random number is greater than the secondary electron emission coefficient, no operation is performed.

8. A device for analyzing photon transmission processes for streamer simulation of complex structure media, characterized in that: include: A first processing module (10) is used to calculate the number of photons radiated by all the partitioned nodes in the simulation area based on a photon radiation model of gas ionization; A second processing module (20) is used to randomly calculate the absorption distance and direction of all photons and determine the target absorption nodes of all photons; The third processing module (30) is used to determine whether all photons are blocked by solid media in the transmission path. If the photons are not blocked by the solid media, secondary electrons generated by photon-induced ionization of oxygen molecules are generated at the target absorption node; if the photons are blocked by the solid media, a collision ionization process between the photons and the solid media is processed, and secondary electrons generated by photon-induced ionization of the solid media are randomly generated according to the secondary electron emission coefficient; The fourth processing module (40) is used to obtain the number of secondary electrons generated by photon-induced ionization at all subdivided nodes in the simulation area, and update the number of electrons at all subdivided nodes after photon-induced ionization.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory, wherein: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

10. A 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 according to any one of claims 1 to 7 are implemented.

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