Photon transport process analysis method and device for complex structured media flow injection simulation, electronic equipment and storage medium

Abstract

The application provides a photon transport process analysis method and device for complex structure medium streamer simulation, electronic equipment and storage medium, belongs to the technical field of high-voltage streamer generation and simulation, and comprises the following steps: calculating the number of photons radiated by all profiled nodes in a simulation region; randomly calculating the absorption distance and direction of all photons, and determining a target absorption node; if the photons are not blocked by a solid medium, generating secondary electrons generated by photon-induced oxygen molecule ionization at the target absorption node; if the photons are blocked by the solid medium, performing photon and solid medium collision ionization process treatment, randomly generating secondary electrons generated by photon-induced solid medium ionization according to a secondary electron emission coefficient; obtaining the number of secondary electrons of all profiled nodes in the simulation region, and updating the number of electrons of all profiled nodes. The application can improve the accuracy of streamer development process simulation and realize the randomness of streamer development process simulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-voltage streamer generation and simulation, and particularly relates to a photon transport process analysis method and device for complex structure medium streamer simulation, an electronic device and a storage medium. BACKGROUND

[0002] Streamers are common discharge phenomena of gas and liquid media under high voltage. On the one hand, power transmission equipment and pulse power devices work under high voltage, and the dielectric that plays an insulating role is prone to streamer discharge under high voltage. Secondly, there is a large range of streamer area in lightning leader, and it is of great significance to study the streamer discharge mechanism for understanding the lightning process. On the other hand, streamer discharge is an effective means of forming low-temperature plasma, and has wide application prospects in waste gas treatment, ozone generation, waste liquid purification, material modification and other fields. Therefore, it has great value to reveal the development process and discharge mechanism of streamers.

[0003] Numerical simulation is an effective method to analyze the development process of streamers. Common streamer simulation models include three types of fluid models, particle models and fluid-particle hybrid models. CN115879385A discloses an insulating medium discharge streamer simulation method considering deflection and branching. The insulating medium is arranged in an electric field environment, and the number range of streamer branching points in the insulating medium and the number range of effective electron avalanches generated by each branching are determined. The control equations and boundary conditions of streamer simulation are constructed based on the fluid dynamics drift-diffusion model and the bipolar carrier model. In the equation solving process, the model parameters are introduced based on the electron avalanche development probability theory correction. The mathematical description and simulation calculation of streamer deflection and branching phenomenon are realized. Finally, the electric field distribution and charge distribution accompanied by the development process of the discharge streamer considering deflection and branching are obtained. It is generally believed that in the air discharge process, the photons radiated when the excited state nitrogen gas transforms into the ground state will cause oxygen molecules to ionize, which is the main mechanism driving the development of positive streamers. Therefore, the process must be considered in the simulation of positive streamers. Most of the current photon radiation-transport calculation methods regard the streamer development area as an unobstructed space. It should be noted that in the field of power transmission equipment and plasma applications, the streamer development area is mostly coexistence of gas and solid medium. Although the streamer only develops in the gas medium, the solid medium plays a blocking role in the photon transport process. However, the existing calculation methods do not consider the blocking effect of solid medium on photon transport, resulting in inaccurate simulation of the development process of streamers. In addition, the existing methods generally convert the integral model of photon radiation-transport into a set of Helmholtz differential equations for solving. This processing method ignores the randomness of photons, so this method cannot simulate the randomness phenomenon in the development process of streamers. SUMMARY

[0004] To solve the above problems, the application provides a photon transport process analysis method, device, electronic equipment and storage medium for complex structure medium stream injection simulation, improves the accuracy of stream injection development process simulation, and realizes the randomness of stream injection development process simulation.

[0005] The application provides a photon transport process analysis method for complex structure medium stream injection simulation, which comprises the following steps:

[0006] Based on the photon radiation model of gas ionization, the number of photons radiated by all profiled nodes in the simulation area is calculated;

[0007] The absorption distance and direction of all photons are randomly calculated to determine the target absorption nodes of all photons;

[0008] It is judged whether all photons are blocked by solid medium on the transmission path, if the photons are not blocked by the solid medium, the secondary electrons generated by the photon-induced oxygen molecule ionization at the target absorption node are generated; if the photons are blocked by the solid medium, the collision ionization process of the photons and the solid medium is processed, and the secondary electrons generated by the photon-induced solid medium ionization are randomly generated according to the secondary electron emission coefficient;

[0009] The number of secondary electrons generated by the ionization of all profiled nodes in the simulation area due to the photon is obtained, and the number of electrons of all profiled nodes after the ionization of the photons is updated.

[0010] As an improvement of the application, the number of photons radiated by all profiled nodes based on the photon radiation model of gas ionization comprises using a discrete distribution to generate a random number to obtain the number of photons radiated by all profiled nodes.

[0011] As an improvement of the application, the formula of the discrete distribution is as follows:

[0012]

[0013] In the formula, is the base of natural logarithm, is the average number of photons radiated by the i-th profiled node, is the i-th power of , and is the probability that the number of radiated photons is i.

[0014] In the formula, is calculated by the following formula:

[0015]

[0016] In the formula, is the gas pressure,​​​ is the pressure, is the proportionality coefficient, is the electron impact ionization coefficient, is the electron mobility, is the electric field intensity of the th split node, is the electron density of the th split node, is the area or volume of a single split grid, is the simulation step length.

[0017] As an improvement of the present application, the random calculation of the absorption distance and direction of all photons, and the determination of the target absorption node of all photons include:

[0018] generating a random number of photon frequency;

[0019] calculating the absorption distance of the photon based on the random number of photon frequency;

[0020] generating a first random number and a second random number as the azimuth angle and zenith angle of photon transmission;

[0021] determining the target absorption node of the photon according to the absorption distance of the photon and the azimuth angle and zenith angle of photon transmission.

[0022] As an improvement of the present application, the random number of photon frequency is generated by using the following formula:

[0023]

[0024] In the formula, and are the minimum and maximum values of the photon frequency, respectively, is a uniform random number in the range of 0-1;

[0025] The absorption distance of the photon is calculated by using the following formula:

[0026]

[0027] In the formula, and are the minimum and maximum values of the oxygen absorption coefficient, respectively, is a uniform random number in the range of 0-1;

[0028] The first random number as the azimuth angle of photon transmission is generated by using the following formula:

[0029]

[0030] In the formula, is the first random number, is a uniform random number in the range of 0-1;

[0031] The second random number is generated as the zenith angle of the photon transmission by using the following formula:

[0032]

[0033] wherein, is the second random number, is a uniform random number in the range of 0-1;

[0034] Assuming that the photon is transmitted along a straight line, the target absorption node of the photon is determined according to the absorption distance and direction of the photon by using the following formula:

[0035]

[0036]

[0037]

[0038] wherein, , , are the axis, axis and axis coordinates of the target absorption node of the photon respectively, , , are the axis, axis and axis coordinates of the initial node where the photon is located respectively, is the axis displacement when the photon is transmitted, is the axis displacement when the photon is transmitted, is the axis displacement when the photon is transmitted.

[0039] As an improvement of the present application, the judging whether all the photons are blocked by the solid medium on the transmission path comprises:

[0040] The step length of the transmission in the direction of the straight line formed by the initial node and the target absorption node is set as , the axis coordinate of the step node is set as = + , the axis coordinate of the step node is set as = , the axis coordinate of the step node is set as + wherein is the number of forward steps;

[0041] determining whether the stepping node is located inside the solid medium, if the stepping node is located outside the solid medium, adding 1 to the number of forward steps repeating the foregoing steps, and determining whether the stepping node reaches the target absorption node, if the stepping node reaches the target absorption node, the iteration 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 iteration process is terminated, indicating that the photon is blocked by the solid medium on the transmission path, and setting a node closest to the stepping node in the gas side as a secondary electron emission node.

[0042] As an improvement of the present application, the secondary electron generated by the photon-induced ionization of the solid medium according to the secondary electron emission coefficient includes generating a random number uniformly distributed in the range of 0-1, if the random number is less than the secondary electron emission coefficient, a secondary electron generated by the photon-induced ionization of the solid medium is generated in the secondary electron emission node; if the random number is greater than the secondary electron emission coefficient, no operation is performed.

[0043] The present application provides a photon transmission process analysis device for complex structure medium flow injection simulation, comprising:

[0044] The first processing module is used for calculating the number of photons radiated by all the profiled nodes in the simulation region based on the photon radiation model of gas ionization;

[0045] The second processing module is used for randomly calculating the absorption distance and direction of all the photons, and determining the target absorption nodes of all the photons;

[0046] The third processing module is used for determining whether all the photons are blocked by the solid medium on the transmission path, if the photons are not blocked by the solid medium, a secondary electron generated by the photon-induced ionization of oxygen molecules is generated in the target absorption node; if the photons are blocked by the solid medium, a collision ionization process of the photons and the solid medium is processed, and a secondary electron generated by the photon-induced ionization of the solid medium is randomly generated according to the secondary electron emission coefficient;

[0047] The fourth processing module is used for obtaining the number of secondary electrons generated by the ionization of all the profiled nodes in the simulation region due to the photons, and updating the number of electrons of all the profiled nodes after the ionization by the photons.

[0048] The present application provides an electronic device, comprising a memory, a processor and a computer program stored in the memory, the processor executes the computer program to realize the steps of the above-mentioned photon transmission process analysis method for complex structure medium flow injection simulation.

[0049] The application provides a storage medium, which stores a computer program, and the computer program realizes the steps of the photon transport process analysis method for complex structure medium streamer simulation when executed by a processor.

[0050] The application can achieve the following beneficial effects by providing a photon transport process analysis method, device, electronic equipment and storage medium for complex structure medium streamer simulation.

[0051] 1. The photon transport process analysis method for complex structure medium streamer simulation can improve the accuracy of streamer simulation in the region blocked by the solid medium by judging whether the photon transport path passes through the solid medium and considering the blocking effect of the solid medium on the photon transport and the process of secondary electrons generated by the collision of the photon with the solid medium, so as to solve the problem that the streamer development process is not accurate enough due to the neglect of the blocking effect of the solid medium in the prior art.

[0052] 2. The photon transport process analysis method for complex structure medium streamer simulation can more accurately simulate the randomness in the electron density and development direction in the streamer development process by analyzing the photon radiation, transport and secondary electron emission process by using a discrete random method and fully considering the randomness of the photon radiation, transport and absorption process, so as to solve the problem that the randomness in the streamer development process cannot be simulated in the prior art.

[0053] 3. The photon transport process analysis method for complex structure medium streamer simulation can quickly judge whether the photon is blocked by the solid medium and obtain the secondary electron emission node, and then simulate the process of the secondary electrons generated by the ionization of the solid medium induced by the photon, thereby improving the accuracy of the streamer development process simulation.

[0054] 4. The photon transport process analysis method for complex structure medium streamer simulation can be combined with the fluid model, particle model and fluid-particle hybrid model of the streamer simulation, and has the advantages of wide applicability and simple calculation. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 FIG. 1 is a flowchart of the photon transport process analysis method for complex structure medium streamer simulation according to an embodiment of the application.

[0056] Figure 2 FIG. 2 is a schematic diagram of the photon transport path of the photon transport process analysis method for complex structure medium streamer simulation according to an embodiment of the application.

[0057] Figure 3 FIG. 3 is a flowchart of the complex structure medium streamer simulation.

[0058] Figure 4 is the electron density evolution graph of Example 1 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0059] Figure 5 is the photon density evolution graph of Example 1 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0060] Figure 6 is the electron density evolution graph of Comparative Example 1 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0061] Figure 7 is the photon density evolution graph of Comparative Example 1 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0062] Figure 8 is the electron density evolution graph of Example 2 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0063] Figure 9 is the electron density evolution graph of Comparative Example 2 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0064] Figure 10 is the electron density evolution graph of Example 3 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0065] Figure 11 is the electron density evolution graph of Comparative Example 3 simulated by the photon transport process analysis method for complex structure medium flow injection simulation based on the embodiment of the application.

[0066] Figure 12 is the structural schematic diagram of the photon transport process analysis device for complex structure medium flow injection simulation according to the second embodiment of the application.

[0067] Label explanation: 10, first processing module; 20, second processing module; 30, third processing module; 40, fourth processing module. DETAILED DESCRIPTION

[0068] The above description is only specific embodiments of the application. Obviously, those skilled in the art can make various modifications and changes without departing from the spirit and scope of the application. Therefore, the detailed description is intended to cover the modifications and changes of the application. Figures 1-12 The application is described in detail to enable those skilled in the art to more fully understand the purpose, features and effects of the application.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. If there is a conflict between the definitions of terms in this disclosure and the meanings of terms as understood by those skilled in the art, the definitions of terms in this disclosure control.

[0070] The present application provides a photon transport process analysis method, device, electronic equipment and storage medium for complex structure medium streamer simulation, on the one hand, considering the blocking effect of solid medium on photon transport, to solve the problem that the streamer development process simulation is not accurate caused by ignoring the blocking effect of solid medium in the prior art, on the other hand, using discrete random method to analyze photon radiation, transport and secondary electron emission process, fully considering the randomness of photon radiation, transport and absorption process, to solve the problem that the randomness phenomenon in the streamer development process cannot be simulated in the prior art.

[0071] Embodiment one

[0072] As a specific embodiment of the present application, the embodiment provides a photon transport process analysis method for complex structure medium streamer simulation, referring to Figure 1 、 Figure 2 , the specific steps are as follows:

[0073] S100, based on the photon radiation model of gas ionization, calculating the number of photons radiated by all profiled nodes in the simulation region;

[0074] S200, randomly calculating the absorption distance and direction of all photons, and determining the target absorption node of all photons;

[0075] S300, judging whether all photons are blocked by solid medium on the transmission path, if the photon is not blocked by the solid medium, generating secondary electrons caused by photon-induced oxygen molecule ionization at the target absorption node; if the photon is blocked by the solid medium, performing collision ionization process of photon and solid medium, and randomly generating secondary electrons caused by photon-induced solid medium ionization according to the secondary electron emission coefficient;

[0076] S400, obtaining the number of secondary electrons generated by ionization induced by photons at all profiled nodes in the simulation region, and updating the number of electrons at all profiled nodes after ionization induced by photons.

[0077] Further, in S100, for the simulation region, the simulation region in two-dimensional space is generally rectangular, and the simulation region in three-dimensional space is generally cuboid.

[0078] Optionally, when the simulation region is meshed, a perpendicular cross meshing method, a triangular meshing method or an adaptive density meshing method can be used. The photon transport process analysis method for complex structure medium flow injection simulation of the embodiment is calculated for the nodes of the meshed grid.

[0079] Specifically, the calculation of the number of photons radiated by all the meshed nodes in the simulation region includes obtaining the number of photons radiated by all the meshed nodes by using a discrete distribution to generate random numbers. Each meshed node generates a number of photons.

[0080] Preferably, the following discrete distribution formula is used:

[0081]

[0082] In the formula, is the base of natural logarithm, is the average number of photons radiated by the th meshed node, is the th power of , and represents the probability that the number of photons radiated is . The formula represents a photon radiation model based on gas ionization.

[0083] Further, the following formula is used for calculation:

[0084]

[0085] In the formula, is the gas pressure, is the quenching gas pressure, is the proportionality coefficient, is the electron collision ionization coefficient, is the electron mobility, is the electric field intensity of the th meshed node, is the electron density of the th meshed node, is the area or volume of a single meshed grid, is the simulation step length.

[0086] Photons mainly come from the photons radiated when the excited state nitrogen molecules de-excite to the ground state, and cause the ionization of oxygen molecules in the air. The number of photons radiated is closely related to the electron collision ionization coefficient, the electron density, the electric field intensity and the electron mobility.

[0087] The photon transport process analysis is part of the particle-in-cell simulation, which includes solving Poisson equation to calculate electric field distribution, solving electron and ion motion equations, solving surface charge accumulation model, and photon transport process analysis calculation, as shown in Figure 3

[0088] The electron density and electric field intensity are obtained by solving the particle-in-cell simulation model. Optionally, the particle-in-cell simulation model can be a fluid model, a particle model, or a fluid-particle hybrid model. The following is described by taking the fluid model and the fluid-particle hybrid model as examples.

[0089] For the fluid model, the motion process of electrons and ions is described by using the drift-diffusion equation, which has:

[0090]

[0091]

[0092]

[0093] In the formula, is the electron density in the simulation process, and are the densities of positive ions and negative ions in the simulation process, respectively, and ± represents the polarity of the ions, is the simulation time, is the electron mobility, is the electric field intensity vector, is the electron diffusion coefficient, , , , are the electron collision ionization source term, the electron attachment source term, the photoionization source term, and the solid medium surface secondary electron emission source term, respectively, and are the mobilities of positive ions and negative ions, respectively, is the mathematical symbol of partial derivative, is the gradient symbol, is the divergence operator.

[0094] Further, the electric field intensity is obtained by solving the Poisson equation, which has:

[0095]

[0096]

[0097] In the formula, is the dielectric constant, is the electric potential, is the space charge density.

[0098] ​The surface charge accumulation model is expressed by the following equation:

[0099]

[0100] In the formula, The surface charge density of the solid medium. This represents the charge flux on the surface of a solid dielectric.

[0101] For the fluid-particle mixing model, the motion of electrons is described by the particle motion equations, and the motion of ions is described by the drift-diffusion equations, namely:

[0102]

[0103]

[0104]

[0105] In the formula, The position vector of the electron. For simulating step size, for Electron displacement over time For the electron migration velocity vector, It is a standard normal distribution vector.

[0106] Furthermore, the electric field strength is obtained by solving the Poisson equation, as follows:

[0107]

[0108]

[0109] The surface charge accumulation model is represented by the following equation:

[0110]

[0111] By iteratively solving the equations of motion of electrons and ions, the Poisson equation, and the surface charge accumulation model, the electron density and electric field strength can be calculated.

[0112] Furthermore, electron mobility, diffusion coefficient, electron collision ionization coefficient, electron adhesion coefficient, and reaction coefficient were calculated using the Phelps collision cross-section dataset in BOLSIG+ software.

[0113] Further, in S200, the random calculation of the absorption distance and direction of all photons, and the determination of the target absorption node of all photons, includes:

[0114] Generate random numbers for photon frequencies;

[0115] The absorption distance of the photon is calculated based on the random number of the photon frequency;

[0116] The first random number and the second random number are generated as the azimuth angle and the zenith angle of the photon transmission;

[0117] The target absorption node of the photon is determined according to the absorption distance of the photon and the azimuth angle and the zenith angle of the photon transmission.

[0118] Optionally, the random number of the photon frequency is generated by using the following formula:

[0119]

[0120] In the formula, and are the minimum value and the maximum value of the photon frequency respectively, is a uniform random number in the range of 0-1.

[0121] In an example, the minimum value of the photon frequency and the maximum value of the photon frequency are 5.25 cm -1 and 300 cm -1 respectively.

[0122] The frequency of the photon has a certain randomness, and this phenomenon is simulated by generating a random frequency in the range of the photon frequency.

[0123] The absorption distance of the photon is calculated by using the following formula:

[0124]

[0125] In the formula, and are the minimum value and the maximum value of the oxygen absorption coefficient respectively, is a uniform random number in the range of 0-1.

[0126] In an example, the minimum value of the oxygen absorption coefficient and the maximum value of the oxygen absorption coefficient are 2.925×10 15 Hz and 3.059×10 15 Hz respectively.

[0127] The absorption distance of the photon is related to the frequency of the photon, and the absorption distance of the photon with different frequencies is calculated by using the above formula.

[0128] The first random number is generated as the azimuth angle of the photon transmission by using the following formula:

[0129]

[0130] In the formula, is a first random number, is a uniform random number in the range of 0-1.

[0131] The second random number is generated as the zenith angle of photon transmission by using the following formula:

[0132]

[0133] wherein, is a second random number, is a uniform random number in the range of 0-1.

[0134] The radiation process of the photon is regarded as isotropic, i.e. the probability of transmission in different directions is the same, so the randomness of the transmission direction is simulated by generating random angles.

[0135] Assuming that the photon is transmitted along a straight line, according to the absorption distance and direction of the photon, the target absorption node of the photon is determined by using the following formula:

[0136]

[0137]

[0138]

[0139] wherein, , , are the axis, axis and axis coordinates of the target absorption node of the photon respectively, , , are the axis, axis and axis coordinates of the initial node where the photon is located respectively, is the axis displacement when the photon is transmitted, is the axis displacement when the photon is transmitted, is the axis displacement when the photon is transmitted.

[0140] Further, in S300, the judging whether all the photons are blocked by the solid medium on the transmission path comprises:

[0141] The step length of transmission in the direction of the straight line formed by the initial node and the target absorption node is set as , and the axis coordinates of the step node are set as = + , Axis coordinates are = + , Axis coordinates are = + ,in This is the number of steps to move forward;

[0142] Determine whether the stepping node is located inside the solid medium. If the stepping node is located outside the solid medium, adjust the forward step count. Add 1, repeat the above steps, and determine whether the stepping node has reached the target absorption node. If the stepping node reaches the target absorption node, the above iterative process terminates, indicating that the photon is not blocked by the solid medium in the transmission path; if the stepping node is located inside the solid medium, the above iterative process terminates, indicating that the photon is blocked by the solid medium in the transmission path.

[0143] In this embodiment, the photon transmission path is considered as a straight line, that is, the straight line formed by the initial node and the target absorbing node. Preferably, the step size is... The mesh size should not exceed the size of the simulation area.

[0144] If the photon is not blocked by a solid medium in its transmission path, it is assumed that the photon can successfully transmit to the target absorption node. After the photon transmits to the target absorption node, it will cause the oxygen molecules at the target absorption node to ionize, thereby generating secondary electrons. Thus, the secondary electrons generated by the photon-induced ionization of oxygen molecules at the target absorption node are produced.

[0145] The emitted photons propagate in all directions and then fall on a target absorption node, causing the oxygen molecules at that node to ionize and generate secondary electrons. If the emitted photons fall on a target absorption node, the oxygen molecules at that node will ionize, and the number of secondary electrons will increase by 1.

[0146] Solid media play a two-fold role in photon transmission and absorption: Firstly, while streamer discharge is generally considered to occur on the gas side, most solid media are opaque, and photons emitted during the discharge process may be blocked by the solid media during transmission, resulting in absorption. Secondly, if photons are blocked by the solid media during transmission, they can trigger photoelectron emission upon collision with the solid media, generating secondary electrons that participate in the streamer discharge process on the gas side. Therefore, it is necessary to determine whether photons are blocked by the solid media during transmission. If so, a collision ionization process between the photons and the solid media is performed, and secondary electrons induced by photon ionization are randomly generated based on the secondary electron emission coefficient.

[0147] If the photon is blocked by the solid medium on the transmission path, the photon collision ionization process with the solid medium is processed. After the photon collides with the solid medium, the secondary electron generated falls on the node closest to the step node in the gas side, the node closest to the step node in the gas side is set as the secondary electron emission node, and the loop is exited. When it is judged that the photon transmission path will encounter the solid medium, the photon will be blocked by the solid medium and will inevitably not be transmitted to the target absorption node, so there is no need to continue the loop.

[0148] The secondary electron generated by the photon-induced ionization of the solid medium is randomly generated according to the secondary electron emission coefficient. A random number uniformly distributed in the range of 0-1 is generated. If the random number is less than the secondary electron emission coefficient, a secondary electron generated by the photon-induced ionization of the solid medium is generated in the secondary electron emission node. If the random number is greater than the secondary electron emission coefficient, no operation is performed.

[0149] The secondary electron emission coefficient is usually much smaller than 1, that is, multiple photons collide with the solid medium to generate one secondary electron, and the process of photon collision with the solid medium to generate secondary electron emission has randomness. The phenomenon can be better simulated by generating a random number.

[0150] The electron number of all the divided nodes after the photon-induced ionization is substituted into the simulation model describing the development of the streamer, and the electric field intensity and electron density of the next simulation step can be obtained.

[0151] The development of the positive streamer is mainly driven by photon radiation-ionization. The number of secondary electrons generated by photon-induced ionization in all the divided nodes in the simulation region is obtained, and then added to the existing electron number to obtain the electron number of all the divided nodes, which is substituted into the streamer simulation model to simulate the development process of the streamer. The final electron number is the sum of the existing electron number of some divided nodes and the number of secondary electrons generated by photon-induced ionization.

[0152] The photon transmission process analysis method for complex structure medium streamer simulation of the embodiment solves the problem that the development process of the streamer is not simulated accurately due to the neglect of the blocking effect of the solid medium in the prior art by judging whether the photon transmission path passes through the solid medium and considering the blocking effect of the solid medium on the photon transmission and the process of generating secondary electrons by the photon colliding with the solid medium. The randomness of the processes of photon radiation, transmission and absorption is fully considered by using a discrete random method to analyze the processes of photon radiation, transmission and secondary electron emission, so as to solve the problem that the randomness phenomenon in the development process of the streamer cannot be simulated in the prior art.

[0153] In addition, the photon transmission process analysis method for complex structure medium streamer simulation of the embodiment can be combined with the fluid model, the particle model and the fluid-particle hybrid model of the streamer simulation, and has the advantages of wide applicability and simple calculation.

[0154] The following is further illustrated by specific examples 1-3 and comparative examples 1-3.

[0155] Example 1

[0156] A solid medium with a porous structure is used to simulate a complex structure medium, and streamer simulation is carried out. The size of the simulation region is 1 mm x 0.5 mm, the length and width of the porous solid medium are 1 mm and 0.25 mm respectively, the upper half of the model is air, and the medium in the air gap inside the porous solid medium is also air. The rod electrode has a length of 0.05 mm and a diameter of 0.01 mm. The electron mobility, diffusion coefficient, electron impact ionization coefficient, electron attachment coefficient, and reaction coefficient are calculated by using the BOLSIG+ software using the Phelps collision cross-section data set; the ion mobility is set to 2 x 10 -4 m 2 (Vs) -1 , and the diffusion coefficient is set to 0. The relative permittivity of the gas and solid medium is 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 15 kV 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 that the initial electrons are placed in a circular area with a radius of 7 mm at the head of the rod electrode, and the total number of electrons is 1000, which is placed according to a Gaussian distribution. The fluid particle mixing model is used to simulate the development process of the streamer, and the photon transport process considers the blocking effect of the solid medium on the photons, but ignores the secondary electron emission process when the photons collide with the solid medium.

[0157] The electron density distribution at different simulation times obtained by simulation is shown in Figure 4 , and the photon density distribution is shown in Figure 5 . As can be seen from the figure, since the electric field intensity at the head of the rod electrode is the highest, the collision ionization reaction in this area is intense, and therefore the streamer develops from the rod electrode; then, the streamer produced by the rod electrode develops towards 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 development of the streamer, part of the emitted photons will enter the pores, and the electric field intensity in the pores is high, and under the combined action of the two, a discharge process will also be formed in part of the pores. However, due to the blocking of the pore wall when the photons transmit to the inside of the pore, the discharge in the pore as a whole is weak, and the streamer mainly develops along the surface of the solid medium and causes breakdown.

[0158] Comparative Example 1

[0159] Using the same geometric model, simulation parameters, and initial conditions as in Example 1, the stream development process was simulated using a fluid particle mixing model. In Comparative Example 1, the photon transmission process neglected the blocking effect of the solid medium on photons, meaning that photons could directly pass through the solid medium for transmission.

[0160] The electron density distribution obtained from the simulation at different simulation times is as follows: Figure 6 As shown, the photon density distribution is as follows Figure 7 As shown in the figure, since Comparative Example 1 neglects the blocking effect of the solid medium on photon transmission, that is, photons can directly pass through the hole wall to reach the inside of the hole, the photon density inside the hole in Comparative Example 1 is... Significantly 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 onset time. For example, Comparative Example 1 exhibits a significant discharge within the pore at 0.238 ns, while Example 1 only begins to discharge within the pore at 0.304 ns. This analysis indicates that because Comparative Example 1 neglects the obstruction effect of the solid medium on photon transmission, the simulated streamer development process, particularly the discharge characteristics within the pore, shows a significant difference. Therefore, when simulating streamers in complex solid media, the obstruction effect of the solid medium on photon transmission must be considered.

[0161] Example 2

[0162] Using the same geometric model, simulation parameters, and initial conditions as in Example 1, the stream development process was simulated using a fluid particle mixing model. The photon transport process considered the blocking effect of the solid medium on photons, as well as the secondary electron emission process when photons collide with the solid medium. The secondary electron emission coefficient of photons colliding with the surface of the solid medium was set to 0.1.

[0163] The electron density distribution obtained from the simulation at different simulation times is as follows: Figure 8 As shown in the figure, considering the secondary electron emission process of photons colliding with the solid medium, the discharge intensity inside the pore is significantly enhanced. This is because photons colliding with the pore wall generate more secondary electrons, which promote the discharge. The discharge process can be roughly described as follows: after the rod electrode discharges, the streamer propagates towards the solid medium and develops along the surface of the solid medium; due to the high electric field intensity inside the pore, discharge also forms inside the pore at 0.221 ns. Under the influence of secondary electrons generated by photons colliding with the pore wall, the discharge inside the pore is strong; after developing to a certain extent, the discharge inside the pore reaches a saturation state, and will develop towards the outside of the pore, merging with the streamers along the surface of the solid medium and causing breakdown.

[0164] Comparative Example 2

[0165] The same geometric model, simulation parameters, and initial conditions as in Example 1 are used, and the fluid particle mixing model is used to simulate the streamer development process. The photon transport process ignores the blocking effect of the solid medium on the photons, but considers the secondary electron emission process when the photons collide with the solid medium. The secondary electron emission coefficient of the photon collision with the surface of the solid medium is set to 0.1.

[0166] The electron density distribution at different simulation times obtained by simulation is shown in FIG. 2. Figure 9 As can be seen from the figure, the discharge intensity in the pore of Comparative Example 2 is weaker than that of Example 2. The main reason is that: both Example 2 and Comparative Example 2 consider the secondary electron emission process when the photons collide with the solid medium, and Comparative Example 2 ignores the blocking effect of the solid medium on the photons. Therefore, the photons in the pore of Comparative Example 2 will radiate to the external space, reducing the number of photons in the pore, i.e., weakening the secondary electron emission effect of the photon collision with the solid medium, and thus weakening the discharge intensity. It can be seen that Comparative Example 2 and Example 2 exhibit different discharge characteristics, further illustrating that the blocking effect of the solid medium on the photon transport process needs to be considered when simulating the streamer in a complex solid medium.

[0167] Example 3

[0168] A solid medium with a porous structure is used to simulate a complex structure medium, and a streamer simulation is carried out. The size of the simulation region is 1 mm x 0.5 mm, the length and width of the porous solid medium are 1 mm and 0.25 mm, respectively, the upper half of the model is air, and the medium in the air gap inside the porous solid medium is also air. The length of the rod electrode is 0.05 mm, and the diameter is 0.01 mm. The electron mobility, diffusion coefficient, electron impact ionization coefficient, electron attachment coefficient, and reaction coefficient are calculated by using the Phelps collision cross-section data set by using the BOLSIG+ software; the ion mobility is set to 2 x 10 -4 m 2 (Vs) -1 , and the diffusion coefficient is set to 0. The relative permittivity of the gas and the solid medium is set to 1 and 4, respectively, and the secondary electron emission coefficient caused by the photon collision with the surface of the solid medium is 0.1. The boundary conditions of the rod electrode and the left boundary are set to 15 kV potential, the right boundary condition is set to ground, and the upper and lower boundary conditions are set to the Neumann boundary condition. The initial conditions for simulation are: the background electron density is set to 10 10 / m 3 , the initial electrons are placed in a circular region with a radius of 7 mm at the head of the rod electrode, and the electron density is 10 14 / m 3 , which is placed according to the Gaussian distribution. The fluid model is used to simulate the streamer development process, and the photon transport process considers the blocking effect of the solid medium on the photons and the secondary electron emission process when the photons collide with the solid medium.

[0169] The electron density distribution obtained from the simulation at different simulation times is as follows: Figure 10 As shown in the figure, since background electrons are present throughout the entire gas medium region, the discharge tends to start from inside the gas gap. The discharge inside the pores merges with the surface discharge excited by the rod electrode, causing breakdown.

[0170] Comparative Example 3

[0171] Using the same geometric model, simulation parameters, and initial conditions as in Example 3, the stream development process was simulated using a fluid model. The photon transmission process neglected the blocking effect of the solid medium on photons, but the secondary electron emission process when photons collide with the solid medium was considered, and the secondary electron emission coefficient of photons colliding with the surface of the solid medium was set to 0.1.

[0172] The electron density distribution obtained from the simulation at different simulation times is as follows: Figure 11 As shown in the figure, the discharge intensity inside and outside the pore in Comparative Example 3 is greater than that in 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 region can be transmitted to each other, resulting in mutual reinforcement 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 illustrating that the blocking effect of the solid medium on photon transmission needs to be considered when simulating complex solid medium streamers.

[0173] Example 2

[0174] As a specific embodiment of the present invention, this embodiment provides a photon transport process analysis device for simulating streamer simulations in complex structural media, referring to... Figure 12 ,include:

[0175] The first processing module 10 is used to calculate the number of photons emitted by all partitioned nodes in the simulation area based on the photon radiation model of gas ionization.

[0176] The second processing module 20 is used to randomly calculate the absorption distance and direction of all photons and determine the target absorption node of all photons.

[0177] The third processing module 30 is used to determine whether all photons are blocked by a solid medium in the transmission path. If the photons are not blocked by a solid medium, secondary electrons generated by photon-induced oxygen molecule ionization are generated at the target absorption node. If the photons are blocked by a solid medium, the collision ionization process of photons and solid medium is processed, and secondary electrons generated by photon-induced solid medium ionization are randomly generated according to the secondary electron emission coefficient.

[0178] The fourth processing module 40 is configured to obtain the number of secondary electrons generated by photoionization of all the dissection nodes in the simulation region, and update the number of electrons of all the dissection nodes after photoionization.

[0179] Embodiment three

[0180] As a specific embodiment of the present application, the embodiment provides an electronic device, comprising a memory, a processor and a computer program stored in the memory, the processor executes the computer program to realize the steps of the method for analyzing the photon transport process of the complex structure medium flow injection simulation in embodiment one:

[0181] S100, based on a photon radiation model of gas ionization, calculating the number of photons radiated by all the dissection nodes in the simulation region;

[0182] S200, randomly calculating the absorption distance and direction of all the photons, and determining the target absorption nodes of all the photons;

[0183] S300, judging whether all the photons are blocked by the solid medium in the transmission path, if the photons are not blocked by the solid medium, generating secondary electrons generated by photoionization of oxygen molecules in the target absorption nodes; if the photons are blocked by the solid medium, performing a collision ionization process of the photons and the solid medium, and randomly generating secondary electrons generated by photoionization of the solid medium according to the secondary electron emission coefficient;

[0184] S400, obtaining the number of secondary electrons generated by photoionization of all the dissection nodes in the simulation region, and updating the number of electrons of all the dissection nodes after photoionization.

[0185] Embodiment four

[0186] As a specific embodiment of the present application, the embodiment provides a storage medium, which stores a computer program, the computer program is executed by a processor to realize the steps of the method for analyzing the photon transport process of the complex structure medium flow injection simulation in embodiment one:

[0187] S100, based on a photon radiation model of gas ionization, calculating the number of photons radiated by all the dissection nodes in the simulation region;

[0188] S200, randomly calculating the absorption distance and direction of all the photons, and determining the target absorption nodes of all the photons;

[0189] S300, judging whether all photons are blocked by the solid medium on the transmission path, if the photons are not blocked by the solid medium, generating secondary electrons generated by photon-induced oxygen molecule ionization at the target absorption node; if the photons are blocked by the solid medium, performing a collision ionization process of the photons and the solid medium, and randomly generating secondary electrons generated by photon-induced solid medium ionization according to a secondary electron emission coefficient;

[0190] S400, obtaining the number of secondary electrons generated by photon-induced ionization at all profiled nodes in the simulation region, and updating the number of electrons of all profiled nodes after photon-induced ionization.

[0191] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in any other form, and any modification or equivalent change made according to the technical essence of the present application still falls within the scope of the present application.

Claims

1. A method of analysis of photon transport processes for complex structured media flow injection simulation, characterized by, The method comprises: calculating the number of photons radiated by all the profiled nodes in the simulation region based on a photon radiation model of gas ionization; randomly calculating the absorption distance and direction of all the photons to determine the target absorption nodes of all the photons; judging whether all the photons are blocked by the solid medium on the transmission path, if the photons are not blocked by the solid medium, generating secondary electrons generated by the ionization of oxygen molecules induced by the photons at the target absorption nodes; if the photons are blocked by the solid medium, performing a collision ionization process of the photons and the solid medium, and randomly generating secondary electrons generated by the ionization of the solid medium induced by the photons according to a secondary electron emission coefficient; obtaining the number of secondary electrons generated by the ionization induced by the photons at all the profiled nodes in the simulation region, and updating the number of electrons at all the profiled nodes after the ionization induced by the photons; wherein the randomly calculating the absorption distance and direction of all the photons to determine the target absorption nodes of all the photons comprises: generating a random number of photon frequency; calculating the absorption distance of the photons based on the random number of photon frequency; generating a first random number and a second random number as the azimuth angle and the zenith angle of the photon transmission; determining the target absorption nodes of the photons according to the absorption distance of the photons and the azimuth angle and the zenith angle of the photon transmission.

2. The method for photon transport process analysis of complex structured media flow-focusing simulation according to claim 1, characterized in that, The calculating the number of photons radiated by all the profiled nodes in the simulation region based on a photon radiation model of gas ionization comprises obtaining the number of photons radiated by all the profiled nodes by generating a random number using a discrete distribution.

3. The method for photon transport process analysis of complex structured media flow injection simulation according to claim 2, characterized in that, The formula of the discrete distribution is: In the formula, The base of the natural logarithm, For the first The average number of photons emitted by each partition node for of Power of 1 The number of photons emitted is The probability of one; wherein, The following formula is used for the calculation: wherein is the gas pressure, is the quenching gas pressure, is the proportionality coefficient, is the electron impact ionization coefficient, is the electron mobility, is the electric field strength of the th split node, is the electron density of the th split node, is the area or volume of a single split grid, is the simulation step.

4. The method of claim 1, wherein, The following formula is used to generate a random number of photon frequency: wherein and are the minimum and maximum values of the photon frequency, respectively, is a uniform random number in the range 0-1; The following formula is used to calculate the absorption distance of the photons: wherein and are the minimum value of the oxygen absorption coefficient and the maximum value of the oxygen absorption coefficient, respectively, is a uniform random number in the range 0-1; The following formula is used to generate a first random number as the azimuth angle of the photon transmission: wherein is a first random number, is a uniform random number in the range 0-1; The following formula is used to generate a second random number as the zenith angle of the photon transmission: wherein is a second random number, is a uniform random number in the range 0-1; The following formula is used to determine the target absorption nodes of the photons according to the absorption distance and direction of the photons, assuming that the photons are transmitted along a straight line: wherein , , are the axis, axis and axis coordinates of the target absorption node of the photon, , , are the axis, axis and axis coordinates of the initial node where the photon is located, is the axis displacement when the photon is transmitted, is the axis displacement when the photon is transmitted, is the axis displacement when the photon is transmitted.

5. The method for photon transport process analysis of complex structured media flow-focusing simulation according to claim 4, wherein, The judging whether all the photons are blocked by the solid medium on the transmission path comprises: The step size is set to be the distance along the straight line formed by the initial node and the target absorbing node. Set step nodes Axis coordinates are = + , Axis coordinates are = + , Axis coordinates are = + ,in This is the number of steps to move forward; determining whether the stepping node is located inside the solid medium, if the stepping node is located outside the solid medium, adding 1 to the step number adding 1, repeating the foregoing steps, and determining whether the stepping node reaches the target absorption node, if the stepping node reaches the target absorption node, the iteration 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 iteration process is terminated, indicating that the photon is blocked by the solid medium on the transmission path, and the node closest to the stepping node in the gas side is set as a secondary electron emission node.

6. The method of claim 1, wherein, The randomly generating secondary electrons generated by the ionization of the solid medium induced by the photons according to a secondary electron emission coefficient comprises generating a random number with uniform distribution in the range of 0-1, if the random number is less than the secondary electron emission coefficient, generating secondary electrons generated by the ionization of the solid medium induced by the photons at the secondary electron emission nodes; if the random number is greater than the secondary electron emission coefficient, not performing any operation.

7. A photon transport process analysis device for complex structured media flow injection simulation, characterized in that, comprise: a first processing module (10) configured to calculate the number of photons radiated by all the profiled nodes in the simulation region based on a photon radiation model of gas ionization; a second processing module (20) configured to randomly calculate the absorption distance and direction of all the photons to determine the target absorption nodes of all the photons; a third processing module (30) configured to judge whether all the photons are blocked by the solid medium on the transmission path, if the photons are not blocked by the solid medium, generate secondary electrons generated by the ionization of oxygen molecules induced by the photons at the target absorption nodes; if the photons are blocked by the solid medium, perform a collision ionization process of the photons and the solid medium, and randomly generate secondary electrons generated by the ionization of the solid medium induced by the photons according to a secondary electron emission coefficient. A fourth processing module (40) is configured to obtain the number of secondary electrons generated by the photoionization of all the split nodes in the simulation region, and update the number of electrons of all the split nodes after the photoionization; The method comprises the following steps: generating a random number of photon frequency; calculating the absorption distance of the photon based on the random number of photon frequency; generating a first random number and a second random number as the azimuth angle and zenith angle of the photon transmission; determining the target absorption node of the photon according to the absorption distance of the photon and the azimuth angle and zenith angle of the photon transmission.

8. An electronic device comprising a memory, a processor, and a computer program stored on the memory, wherein the computer program comprises instructions that, when executed by the processor, cause the electronic device to perform the method of any one of claims 1-7. The processor executes the computer program to implement the steps of the method of any one of claims 1-6.

9. A storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the steps of the method of any one of claims 1-6.

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