First collision source determination method and device for shielding calculation

Abstract

The embodiment of the invention belongs to the field of numerical simulation, and particularly relates to a first collision source determination method and device for shielding calculation, and the method comprises the steps: obtaining the information of a source item of an emitted particle and the information of a preset first collision point of the particle, the preset first collision point represents the first collision position of the particles and the substance in the transportation process; determining one or more geometry models for representing a passing area according to the passing area when the particle reaches a preset first collision point; and calculating the passing distance of the particle in each geometry model, and determining a first collision source corresponding to a preset first collision point according to the passing distance and the material information corresponding to each geometry model. According to the embodiment of the invention, the problem of high calculation cost of the first collision source in the existing analog calculation is solved.

Description

Technical Field

[0001] The embodiments of this specification relate to the field of numerical simulation, and more particularly to a method and apparatus for determining a first collision source for shielding calculation. Background Art

[0002] In numerical simulations, a first collision source (FCS) is often used to mitigate the ray effect produced by the discrete ordinates method (SN) to achieve more accurate shielding calculations. Calculating the first collision source requires calculating the optical distance from the source to the first collision point, which is the most time-consuming part of the entire process.

[0003] At present, the grid-based ray tracing method is mainly used in engineering practice. This method has an acceptable computational cost when using structured grids. However, for unstructured grids, the computational cost of this method is too high. Since the structural information of unstructured grids is more diverse, more computing resources are required when calculating FCS, which limits its application value in actual engineering. If it is not combined with FCS, it is difficult to overcome the ray effect produced by the SN method, resulting in low accuracy of shielding calculation. Summary of the Invention

[0004] The embodiments of this specification provide a method and apparatus for determining a first collision source for shielding calculation, which are used to solve or at least partially solve the problem of high computational cost of the first collision source in existing shielding calculations.

[0005] In order to solve the above technical problems, a first aspect of an embodiment of this specification provides a method for determining a first collision source for shielding calculation, the method comprising:

[0006] Acquiring information about a source item of emitted particles and information about a preset first collision point of the particles, wherein the preset first collision point represents a position where the particles first collide with a substance during transport;

[0007] Determining one or more geometric models for representing the area passed by the particle when the particle reaches the preset first collision point;

[0008] The travel distance of the particle in each of the geometric models is calculated, and a first collision source corresponding to a preset first collision point is determined according to the travel distance and material information corresponding to each of the geometric models.

[0009] Furthermore, before obtaining the information of the source item of the emitted particles and the information of the preset first collision point of the particles, the method further includes:

[0010] Constructing a total grid area including a preset first collision point and the source term;

[0011] Generating a set of geometric models corresponding to the total grid area;

[0012] Determining the grid area that each computing core is responsible for based on each computing core and the total grid area;

[0013] The source item information, the geometric model set and the corresponding material information, and the grid area that each computing core is responsible for are sent to the corresponding computing core.

[0014] Furthermore, calculating the travel distance of the particle in each of the geometric models includes:

[0015] Determining the entry and exit positions of the particles in each of the geometric models according to the information of the source term and the information of the preset first collision point;

[0016] Each computing core calculates in parallel the travel distances of the particle corresponding to different first collision points based on the penetration position and the exit position.

[0017] Furthermore, determining a first collision source corresponding to a preset first collision point according to the travel distance and the material information corresponding to each of the geometric models includes:

[0018] Determining the total travel distance of the particles corresponding to the same material information according to the travel distance of the particles in each of the geometric models;

[0019] Get the total cross section of the geometric model corresponding to the same material information;

[0020] Determining the optical distance of the particle based on the total travel distance and total cross-section of the particle in different materials;

[0021] A first collision source corresponding to a preset first collision point is determined according to the optical distance.

[0022] Furthermore, the first collision source determination method for shielding calculation also includes:

[0023] Get information about reflection boundaries;

[0024] Constructing a virtual source term that takes the reflection boundary as the symmetry axis and is symmetrical to the source term;

[0025] Determining, based on the virtual source term and the preset first collision point, an intersection point between a travel path of an emitted particle of the virtual source term and the reflection boundary;

[0026] The travel distance of the emitted particles of the virtual source item in each of the geometric models is determined according to the area through which the emitted particles of the source item pass when reaching the preset first collision point via the intersection point after being emitted.

[0027] Furthermore, the first collision source determination method for shielding calculation also includes:

[0028] Determining an encryption threshold according to a preset grid refinement factor and a particle travel distance between a source term and the preset first collision point;

[0029] Encrypt the grid in the grid area where the source item is located according to the encryption threshold;

[0030] A first collision source corresponding to a preset first collision point is determined according to the travel distance, the grid of the grid area where the source item is located, and material information.

[0031] Furthermore, the grid of the grid area where the source item is located is encrypted according to the encryption threshold, including:

[0032] Determine whether the size of the grid in the grid area where the source item is located is greater than the encryption threshold;

[0033] If the answer is yes, recursively encrypt the grid in the grid area where the source item is located.

[0034] Furthermore, the grid in the grid area where the source item is located is recursively encrypted, including:

[0035] Divide the grid in the grid area where the source item is located into subgrids;

[0036] Calculating the distance between the center of the sub-grid and the preset first collision point;

[0037] Updating the encryption threshold according to a preset grid refinement factor and a distance between the center of the subgrid and the preset first collision point;

[0038] When the size of a subgrid is larger than the updated encryption threshold, the subgrid is sub-grid-divided, and the sub-grid division operation according to the encryption threshold is continuously performed until the number of divisions reaches the preset grid division threshold.

[0039] A second aspect of the embodiments of this specification provides a first collision source determination device for shielding calculation, the device comprising:

[0040] an acquisition module, configured to acquire information about a source item of emitted particles and information about a preset first collision point of the particles, wherein the preset first collision point represents a position where the particles first collide with a substance during transport;

[0041] A first determining module is used to determine one or more geometric models for representing the area passed by the particle when reaching the preset first collision point;

[0042] The second determining module is used to calculate the travel distance of the particle in each of the geometric models, and determine the first collision source corresponding to the preset first collision point according to the travel distance and the material information corresponding to each of the geometric models.

[0043] A third aspect of the embodiments of this specification provides a computer device, comprising a memory, a processor, and a computer program stored in the memory, wherein when the computer program is executed by the processor, the computer device executes instructions of the method for determining the first collision source for shielding calculation described in any of the aforementioned embodiments.

[0044] A fourth aspect of the embodiments of this specification provides a computer storage medium having a computer program stored thereon. When the computer program is executed by a processor of a computer device, the computer program executes the instructions of the method for determining the first collision source for shielding calculation described in any of the aforementioned embodiments.

[0045] A fifth aspect of the embodiments of this specification provides a computer program product, which includes a computer program. When the computer program is executed by a processor of a computer device, the computer program executes instructions of the method for determining the first collision source for shielding calculation described in any of the above embodiments.

[0046] The embodiments of this specification provide a method and apparatus for determining the first collision source for shielding calculations. By obtaining information about the source term of the emitted particles and information about the preset first collision point of the particles, the method and apparatus determine the area through which the particles pass when they reach the preset first collision point, and determine one or more geometric models representing the area based on the area passed, thereby directly calculating the particle travel distance based on the geometric model, bypassing the continuous grid, greatly reducing the computational complexity. Finally, the first collision source is determined based on the travel distance and the material information corresponding to the geometric model, thereby reducing the cost of shielding calculations.

[0047] In order to make the above and other purposes, features and advantages of the embodiments of this specification more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 A flow chart of a method for determining a first collision source for shielding calculation according to an embodiment of this specification is shown;

[0050] Figure 2 A flow chart showing an embodiment of this specification sending information to each computing core is shown;

[0051] Figure 3 A flow chart showing the calculation of particle travel distance according to an embodiment of this specification is shown;

[0052] Figure 4 A flowchart of determining the source of the first collision according to an embodiment of this specification is shown;

[0053] Figure 5 A flow chart of a method based on symmetric source terms according to an embodiment of this specification is shown;

[0054] Figure 6 A flow chart is shown when the particle travel distance between the source item and the preset first collision point in the embodiment of this specification is less than a first preset threshold;

[0055] Figure 7 A first flow chart of encrypting a grid according to an embodiment of this specification is shown;

[0056] Figure 8 A second flow chart of encrypting a grid according to an embodiment of this specification is shown;

[0057] Figure 9 A schematic plan view of a geometric model according to an embodiment of the present specification is shown;

[0058] Figure 10 A schematic diagram of a symmetric source term according to an embodiment of the present specification is shown;

[0059] Figure 11 A schematic diagram of an encrypted grid according to an embodiment of the present specification is shown;

[0060] FIG12( a ) shows a schematic diagram of the material distribution in the x,y plane of the environment where the source item is located according to an embodiment of this specification;

[0061] FIG12( b ) shows a schematic diagram of the material distribution in the x,z plane of the environment where the source item is located according to an embodiment of this specification;

[0062] Figure 13 A first schematic diagram showing angular fluxes at different positions according to an embodiment of this specification is shown;

[0063] Figure 14 A first schematic diagram showing the calculated deviation of angular flux at different positions according to an embodiment of this specification is shown;

[0064] Figure 15A second schematic diagram showing angular flux at different positions according to an embodiment of this specification is shown;

[0065] Figure 16 A second schematic diagram showing the calculated deviation of angular flux at different positions according to an embodiment of this specification is shown;

[0066] Figure 17 A first schematic diagram of angular flux distribution according to an embodiment of this specification is shown;

[0067] Figure 18 A second schematic diagram showing the angular flux distribution of an embodiment of this specification is shown;

[0068] Figure 19 A structural diagram of a first collision source determination device for shielding calculation according to an embodiment of this specification is shown;

[0069] Figure 20 The diagram shows the structure of the computer device according to the embodiment of the present specification.

[0070] Description of the accompanying symbols:

[0071] 1910, get module;

[0072] 1920, first determination module;

[0073] 1930, second determination module;

[0074] 2002, computer equipment;

[0075] 2004, processor;

[0076] 2006, Memory;

[0077] 2008, driving mechanism;

[0078] 2010, Input / Output Module;

[0079] 2012, Input Devices;

[0080] 2014, output devices;

[0081] 2016, Presentation Equipment;

[0082] 2018, Graphical User Interface;

[0083] 2020, Network Interface;

[0084] 2022, communication link;

[0085] 2024. Communication bus. DETAILED DESCRIPTION

[0086] The following will clearly and completely describe the technical solutions in the embodiments of this specification in conjunction with the drawings in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the embodiments of this specification.

[0087] It should be noted that the terms "first," "second," and the like in this specification, the claims, and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this specification described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0088] This specification provides method operation steps as described in the embodiments or flowcharts, but more or fewer operation steps may be included based on routine or non-creative work. The order of steps listed in the embodiments is only one way of executing the steps among many orderings and does not represent the only execution order. When a system or device product is actually executed, the method can be executed in the order shown in the embodiments or the drawings or in parallel.

[0089] It should be noted that the acquisition, storage, use, and processing of data in the technical solutions of the embodiments of this specification comply with the relevant provisions of national laws and regulations.

[0090] It should be noted that in the embodiments of this specification, certain software, components, models and other existing solutions in the industry may be mentioned. They should be regarded as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solutions of the embodiments of this specification, but it does not mean that the applicant has or will necessarily use the solution.

[0091] In the field of shielding calculations, the Discrete Ordinates Method (SN) is a widely used numerical method that solves the transport equation by discretizing the angular dimension. However, when dealing with isolated point source problems or large cavity structures, the SN method often produces ray effects at specific discrete angles, resulting in inaccurate calculation results. In order to mitigate the impact of this phenomenon, it is usually necessary to combine the First Collision Source (FCS) method. Compared with core calculations, shielding analysis involves more complex geometric features such as supporting structures, instruments and components, and therefore places higher demands on geometric description capabilities. Unstructured grid technology can meet this demand and provide more accurate geometric representation.

[0092] During the calculation of the first collision source, the optical distance from the source to the target mesh is calculated using ray tracing, which is the most time-consuming part of the entire process. The core of the ray tracing algorithm is to determine the distance that a ray travels through each material on its way from the source to the target.

[0093] Currently, grid-based ray tracing methods are primarily used in engineering practice. While this method offers acceptable computational complexity when using structured grids, its geometric description capabilities are limited. When using unstructured grids for spatial discretization, traditional ray tracing algorithms are computationally expensive and difficult to implement in parallel, limiting their practical application in engineering.

[0094] To this end, in one embodiment of this specification, a method for determining a first collision source for shielding calculation is provided to solve the problem of high computational cost of the first collision source in existing shielding calculation.

[0095] Specifically, such as Figure 1 As shown, the first collision source determination method for shielding calculation includes:

[0096] Step 110, obtaining information of a source term of emitted particles and information of a preset first collision point of the particles, wherein the preset first collision point represents a position where the particles first collide with a substance during transport;

[0097] Step 120, determining one or more geometric models for representing the area passed by the particle when it reaches the preset first collision point;

[0098] Step 130 : calculating the travel distance of the particle in each of the geometric models, and determining the first collision source corresponding to the preset first collision point based on the travel distance and the material information corresponding to each of the geometric models.

[0099] This embodiment obtains information about the source term of the emitted particles and the information about the preset first collision point of the particles to determine the area that the particles pass through when reaching the preset first collision point, and determines one or more geometric models representing the area based on the passed area, thereby directly calculating the particle travel distance based on the geometric model, bypassing the continuous grid, greatly reducing the calculation complexity. Finally, the first collision source is determined based on the travel distance and the material information corresponding to the geometric model, reducing the cost of shielding calculation.

[0100] The goal of shielding calculation is to solve the neutron transport equation. Considering the vacuum boundary and the multi-group transport equation of the isotropic point source at the target point, the equation is:

[0101]

[0102] Among them, r represents the spatial coordinate, Ω represents the discrete direction, g and g′ represent the energy group, represents the total cross section at position r, represents the scattering cross section at position r, that is, the scattering coefficient from energy group g′ to g at position r, Ψ is the angular flux, G is the number of energy groups, L is the maximum order of the spherical harmonic expansion, Y is the spherical harmonic function, n is the order of the spherical harmonic function, k is the azimuthal quantum number of the spherical harmonic function, φ is the flux moment, q fis is the fission source, δ represents the unit pulse function, q ext It is a fixed source.

[0103] When the first collision source is introduced, the shielding problem can be split into solving the uncolliding angular flux and the collision angular flux, that is, Among them, ψ u represents the uncolliding angular flux, ψ c represents the collision angular flux.

[0104] The uncollision angular flux is determined by the initial fixed source term and the optical distance. The first collision source is then determined from the uncollision angular flux. Solving the collision angular flux requires treating the first collision source as a new source term and solving it based on the SN method. To this end, when calculating the first collision source, shielding calculations typically divide the space containing the initial fixed source term and the first collision point into a total grid area consisting of multiple grids. The optical distance is calculated based on the particle's travel distance in each grid and the corresponding material properties of the grid, and the first collision source is then determined from the optical distance.

[0105] In the embodiments of this specification, considering that the particle does not collide with the material before reaching the first collision point, its travel direction during the transport process can be considered to remain unchanged. Therefore, in order to reduce the amount of calculation of the optical distance, the area through which the particle passes during the travel process is constructed as a geometric model. Therefore, when calculating the optical path, it is only necessary to consider the travel distance of the particle in the geometric model and the material information corresponding to the geometric model to determine the optical distance traveled by the particle in each geometric model, thereby determining the total optical distance when the particle reaches the first collision point, and then obtaining the first collision source. Figure 9 It is a planar schematic diagram of the unstructured grid area containing a fixed source item and the first collision point (the arrow in the figure indicates that the fixed source item points to the first collision point). The bold border area in the lower left corner is a schematic plane of the geometric model composed of multiple grids.

[0106] In some embodiments of this specification, Figure 2 As shown, before obtaining the information of the source item of the emitted particles and the information of the first collision point preset by the particles, it also includes:

[0107] Step 210 , constructing a total grid area including a preset first collision point and the source item;

[0108] Step 230, generating a set of geometric models corresponding to the total grid area;

[0109] Step 230, determining the grid area that each computing core is responsible for based on each computing core and the total grid area;

[0110] Step 240 : Send the source item information, the geometric model set and corresponding material information, and the grid area that each computing core is responsible for to the corresponding computing core.

[0111] This embodiment constructs a total grid area including target points and source items, and determines computing cores responsible for different grid areas. The optical distance calculation is completed in parallel by the computing cores, thereby improving the calculation efficiency of the first collision source.

[0112] In unstructured grids, to save computing resources, information is not shared between different computing cores. When calculating the optical distance of a particle, the previous computing core determines the particle's exit position before the next computing core in the adjacent grid area knows the particle's entry direction and continues to calculate the particle's optical distance in the grid area that the computing core is responsible for. Therefore, the total optical distance calculation requires continuous waiting time and information exchange between different computing cores, resulting in low computing efficiency.

[0113] In the embodiments of this specification, by dividing the total grid area into different sub-grid areas, and then distributing the source item information, the geometric model and material information corresponding to the total grid area, and the divided sub-grid areas to the corresponding computing cores, each computing core has a global view and can directly determine the movement of the particle when it reaches the first collision point in the grid area it is responsible for, thereby realizing parallel calculation of optical distances without the need for information exchange with the previous computing core. In addition, by constructing a geometric model to replace each small grid, the amount of computational information is greatly reduced, and low-cost parallel computing is achieved. The geometric model can be a CAD model, and the travel distance of the particle in the model is directly calculated by CAD, or it can be other types of models, which are not limited in this specification.

[0114] Specifically, in one embodiment of this specification, Figure 3 As shown, calculating the travel distance of particles in each of the geometric models includes:

[0115] Step 310: determining the entry and exit positions of the particle in each of the geometric models based on the source item information and the preset first collision point information;

[0116] In step 320 , each computing core concurrently calculates the travel distances of the particle corresponding to different first collision points based on the entry position and the exit position.

[0117] In this embodiment, each computing core can determine the particle's movement when it reaches the first collision point in the grid area it is responsible for (that is, the entry and exit positions of each geometric model that the particle passes through when it reaches the first collision point in the grid area it is responsible for after starting from the source item) based on the information of the source item and the information of the preset first collision point. This eliminates the need for information exchange with the previous computing core, thereby improving the efficiency of optical distance calculation.

[0118] Since each computing core stores source information, the geometric model of the total grid area and the corresponding material information, as well as the responsible sub-grid area information, each computing core can determine the first collision points in the grid area it is responsible for (each grid point in the grid area is regarded as the first collision point). The particle's travel direction can be determined based on the source term and the first collision point, thereby determining the particle's travel conditions when it passes through each geometric model and reaches the first collision point in the grid area it is responsible for. Afterwards, each computing core starts parallel calculations to obtain the optical distance of the particle corresponding to different first collision points.

[0119] In another embodiment of this specification, Figure 4 As shown, determining the first collision source corresponding to the preset first collision point according to the travel distance and the material information corresponding to each of the geometric models includes:

[0120] Step 410, determining the total travel distance of the particles corresponding to the same material information based on the travel distance of the particles in each of the geometric models;

[0121] Step 420 , obtaining the total cross-section of the geometric model corresponding to the same material information;

[0122] Step 430 , determining the optical distance of the particle based on the total travel distance and total cross-section of the particle in different materials;

[0123] Step 440: Determine a first collision source corresponding to a preset first collision point according to the optical distance.

[0124] This embodiment determines the total travel distance of particles corresponding to the same material information based on the travel distance of the particles in each geometric model, and determines the total optical distance of the particles corresponding to the same material based on the total travel distance and the total cross-section of the geometric models corresponding to the same material information, further improving the efficiency of optical distance calculation.

[0125] In shielding calculations, the total cross-section refers to the sum of the cross-sections of various possible processes of interaction between particles and matter, that is, a physical quantity that characterizes the probability of interaction between particles and matter. After obtaining the travel distance of the particle in the geometric model, the total cross-section is used as the weight of the travel distance and combined with the travel distance to obtain the optical distance. Afterwards, the non-collision flux is determined based on the optical distance, and the first collision source is obtained after scattering (collision) calculation of the non-collision flux.

[0126] In another embodiment of this specification, Figure 5 As shown, the first collision source determination method for shielding calculation also includes:

[0127] Step 510, obtaining reflection boundary information;

[0128] Step 520, constructing a virtual source term that takes the reflection boundary as the symmetry axis and is symmetrical to the source term;

[0129] Step 530: determining the intersection of the travel path of the emitted particles of the virtual source term and the reflection boundary according to the virtual source term and the preset first collision point;

[0130] Step 540 : determining the travel distance of the emitted particles of the virtual source item in each of the geometric models according to the area through which the emitted particles of the source item pass when reaching the preset first collision point via the intersection point after being emitted.

[0131] This embodiment considers the problem of determining the travel distance of particles due to the reflection boundary problem. When the total grid area only contains partial spatial information due to the setting of the reflection boundary, the total travel distance of particles emitted from the source area grid representing all spatial information can be determined through equivalent substitution without expanding the grid, thereby reducing the computing resources required by each computing core.

[0132] Figure 10 It is a schematic diagram of the source term including the reflection boundary. The right end of the reflection boundary is the real source term. The real source term is mapped with the reflection boundary as the symmetry axis to obtain the virtual source term on the left end of the reflection boundary, and the intersection of the virtual source term and the first collision point at the reflection boundary is determined. According to the symmetry property, the line connecting the real source term and the intersection point, as well as the line connecting the intersection point and the first collision point are combined to equivalently replace the travel distance of the particle emitted from the virtual source term.

[0133] Considering the following relationship between the uncollision angular flux and the travel distance:

[0134]

[0135] Among them, ψ u represents the unimpacted angular flux, τ represents the optical distance, Represents the distance from the source item r to the first collision point r p travel distance.

[0136] From this we can see that when When it approaches 0, Ψ u That is, the shorter the travel distance, the higher the uncollision angular flux will be. Therefore, the calculation accuracy of short-distance travel has a significant impact on the calculation results.

[0137] To this end, in one embodiment of this specification, Figure 6 As shown, the first collision source determination method for shielding calculation also includes:

[0138] Step 610, determining an encryption threshold according to a preset grid refinement factor and a particle travel distance between a source term and the preset first collision point;

[0139] Step 620, encrypting the grid of the grid area where the source item is located according to the encryption threshold;

[0140] Step 630 : Determine a first collision source corresponding to a preset first collision point according to the travel distance, the grid and material information of the grid area where the source item is located.

[0141] This embodiment considers encrypting the grid in the grid area where the source item is located when the encryption threshold is met, subdividing the original grid into smaller grids, determining the travel distance through the encrypted grid, and determining the first collision source corresponding to the preset first collision point based on the travel distance, the encrypted grid, and the material information corresponding to the encrypted grid, thereby improving the calculation accuracy of particles traveling short distances.

[0142] In another embodiment of this specification, Figure 7 As shown, a method for mesh encryption is provided, including:

[0143] Step 710, determining whether the size of the grid in the grid area where the source item is located is greater than the encryption threshold, if so, executing step 720;

[0144] In the above step 710, if the size of the grid in the grid area where the source item is located is not greater than the encryption threshold, it means that the size of the grid area where the source item is located can meet the calculation accuracy requirement, and grid encryption may not be performed;

[0145] Step 720: recursively encrypt the grid in the grid area where the source item is located.

[0146] This embodiment compares the size of the grid in the grid area where the source item is located with an encryption threshold, and recursively encrypts the grid in the grid area where the source item is located when the encryption threshold is met, thereby realizing the association between the grid size and the travel distance and improving the effect of grid encryption.

[0147] The following formula is used to determine whether the grid is refined:

[0148]

[0149] in, Represents the distance from the source item r to the first collision point r p The travel distance, ε represents the grid refinement factor, v cell Represents the mesh volume.

[0150] In another embodiment of this specification, Figure 8 As shown in the figure, the grid in the grid area where the source item is located is recursively encrypted, including:

[0151] Step 810, dividing the grid in the grid area where the source item is located into subgrids;

[0152] Step 820, calculating the distance between the center of the sub-grid and the preset first collision point;

[0153] Step 830: updating the refinement threshold according to a preset grid refinement factor and the distance between the subgrid center and the preset first collision point;

[0154] Step 840 : When the size of the sub-grid is larger than the updated encryption threshold, the sub-grid is divided into sub-grids, and the sub-grid division operation according to the encryption threshold is continuously performed until the number of divisions reaches the preset grid division threshold.

[0155] This embodiment implements dynamic updating of the encryption threshold and recursive encryption of the grid based on the encryption threshold. The grid encryption effect is further improved by continuously correlating the grid size with the travel distance.

[0156] The meshing threshold can be 5, 6, 7, etc. (indicating a maximum number of meshing divisions of 5, 6, 7, etc.), determined based on actual conditions and not limited in this specification. The meshing threshold is set here because the inventors found during experiments that when the mesh is encrypted to a certain number of times, the computational accuracy does not improve significantly, but the computational effort increases significantly. Therefore, the meshing threshold is set to balance the actual application effect.

[0157] Figure 11 The diagram shows the meshing process, where the center of the large grid is the first collision point, and the source grid is located in the lower left quarter. Initially, the travel distance is calculated using the center of the source grid as the source item. The decision to resize the source grid is based on its size and travel distance. If resize is necessary, the source grid is decomposed into four subgrids by connecting the midpoints of its four sides. The center distances of the newly generated subgrids (i.e., the travel distances between the subgrid center and the first collision point) are iteratively determined layer by layer (i.e., comparing the subgrid's resize threshold with the subgrid's size). Based on the determination, the subgrids are further divided until the number of mesh divisions reaches the preset meshing threshold. The small black dots in the diagram are the subgrid center points.

[0158] In some embodiments of this specification, specific experimental data are provided. Figure 12 (a) and Figure 12 (b) respectively show the material distribution diagrams of the x, y plane and x, z plane of the space under vacuum boundary conditions. The horizontal axis and vertical axis are reflection boundaries (taking into account the case of symmetric source terms), "Vacuum" represents the vacuum boundary, and "Reflective" represents the reflection boundary. The spatial regions (Reg) "1", "2", and "3" represent the source region (Source), the cavity region (Void), and the shield region (Shield), respectively. The corresponding source intensity and material key information are shown in Table 1 below. Among them, case 1 represents the case where there is no scattering reaction between the particles and the shielding material, and case 2 represents the case where there is a 50% probability of scattering between the particles and the shielding material.

[0159] Table 1

[0160]

[0161] In Table 1, the source term is located in region 1, so the source intensity in region 1 is set to 1 cm -3 ·s -1 , and other areas are 0.

[0162] Next, for the calculation of the first collision source, a grid-based ray tracing algorithm on an unstructured grid was compared with the geometric model-based ray tracing algorithm of this scheme. The experimental results are shown in Table 2. The total number of grid cells is 215,024, the number of grid cells in the source region is 253, and the total number of grid points is 39,021. The number of rays to be calculated is: 8 (number of reflections) × 253 (number of source points) × 39,021 (number of target grid points) = 78,978,504.

[0163] Table 2

[0164] method Ray tracing time / s Number of rays calculated per second Grid-based ray tracing algorithm 12325.0 6408 Ray tracing algorithm based on geometric model 68.4 1154656

[0165] As shown in Table 2, the ray tracing algorithm based on the geometric model (this solution) takes only 68.4 seconds and can calculate 1,154,656 rays per second, which greatly improves the computational efficiency compared to the grid-based ray tracing algorithm.

[0166] Set the angle discretization order to S16, the first collision source mesh refinement factor to 0.013, and select points with XYZ coordinates of (5cm, 5cm, 5cm), (15cm, 15cm, 15cm), ..., (95cm, 95cm, 95cm) as measurement points for comparison with the analytical solution. Figure 13 and Figure 14 Respectively represent the angular flux and maximum relative deviation of each position in the case 1 scene, Figure 15 and Figure 16 Respectively represent the angular flux and maximum relative deviation of each position in the case 2 scene.

[0167] Figures 13 to 16In the data, "Flux" represents flux, "Position" represents position, "Ref" represents the reference solution, "FCSOFF" represents the calculation result based on an unstructured grid without a first collision source, and "FCS ON" represents the calculation result of this solution using a first collision source based on a geometric model. In the case 1 scenario, the maximum relative deviations of "FCS OFF" and "FCS ON" are 132.82% and -13.32%, respectively. In the case 2 scenario, the maximum relative deviations of "FCS OFF" and "FCS ON" are 76.65% and 26.43%, respectively. This shows that this solution, based on the geometric model, successfully achieves flux calculation after introducing a first collision source. Furthermore, because this solution is based on a geometric model, the computational cost is greatly reduced, making it possible to introduce a first collision source to improve the accuracy of shielding calculations.

[0168] Figure 17 and Figure 18 The figures represent the angular flux distribution of the existing unstructured grid ray tracing algorithm and the geometric model-based method of this solution in the case 2 scenario. The deepest color at the bottom is the source area where the source term is located. Figure 17 In the source region, there are jagged rays pointing outwards, while in Figure 18 In the middle, the transition from the source region to the outer side is smoothed, and the ray effect is not obvious.

[0169] Based on the same inventive concept, embodiments of this specification also provide a device for determining a first collision source for shielding calculations, as described in the following embodiments. Because the principles underlying the problem solved by the device for determining a first collision source for shielding calculations are similar to those of the method for determining a first collision source for shielding calculations, the implementation of the device for determining a first collision source for shielding calculations can be referenced to the method for determining a first collision source for shielding calculations, and any repetitions will not be repeated.

[0170] Specifically, such as Figure 19 As shown, the first collision source determination device for shielding calculation includes:

[0171] An acquisition module 1910 is configured to acquire information about a source term of emitted particles and information about a preset first collision point of the particles, where the preset first collision point represents a location where the particles first collide with matter during transport.

[0172] A first determining module 1920 is configured to determine one or more geometric models representing the area that the particle passes through when reaching a preset first collision point;

[0173] The second determination module 1930 is configured to calculate the travel distance of the particle in each of the geometric models, and determine a first collision source corresponding to a preset first collision point based on the travel distance and material information corresponding to each of the geometric models.

[0174] The embodiments of this specification provide a method and apparatus for determining the first collision source for shielding calculations. By obtaining information about the source term of the emitted particles and information about the preset first collision point of the particles, the method and apparatus determine the area through which the particles pass when they reach the preset first collision point, and determine one or more geometric models representing the area based on the area passed, thereby directly calculating the particle travel distance based on the geometric model, bypassing the continuous grid, greatly reducing the computational complexity. Finally, the first collision source is determined based on the travel distance and the material information corresponding to the geometric model, thereby reducing the cost of shielding calculations.

[0175] It should be noted that the embodiments of this specification achieve the following technical effects:

[0176] (1) Improved computational efficiency. By replacing the traditional mesh traversal algorithm with ray tracing based on the geometric model, the strong correlation between the computational effort and the mesh density is eliminated, and the complexity of optical distance calculation is reduced in complex geometric scenes (from O(N) to O(1)), significantly reducing the time consumption of single ray tracing.

[0177] (2) Parallel computing optimization. The regional decomposition parallel architecture combined with the lightweight geometry model distribution mechanism breaks through the bottlenecks of global data redundancy or high-frequency communication in unstructured grid parallelism, making memory usage and communication overhead independent of the grid encryption scale and maintaining high load balancing.

[0178] (3) Optimization of computational accuracy in the near-source region. Based on the distance criterion, an adaptive mesh refinement strategy is used to dynamically implement multi-level recursive subdivision in the near-source region (i.e., the grid region where the source term is located) to achieve directional improvement of local accuracy. At the same time, the maximum refinement depth constraint is used to avoid excessive computational resource consumption.

[0179] (4) Enhanced compatibility with complex geometries. It can efficiently analyze geometric models constructed using Boolean operations, avoid discretization errors in structural mesh surfaces, and improve the geometric fidelity of complex assemblies in shielding calculations.

[0180] In one embodiment of this specification, a computer device is further provided for implementing the method described in any of the above embodiments, such as Figure 20The diagram shows a schematic diagram of the structure of a computer device according to an embodiment of the present specification. The computer device 2002 may include one or more processors 2004, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. The computer device 2002 may also include any memory 2006 for storing any type of information, such as code, settings, data, etc. For example, and without limitation, the memory 2006 may include any one or more combinations of the following: any type of RAM, any type of ROM, a flash memory device, a hard disk, an optical disk, etc. More generally, any memory may use any technology to store information. Furthermore, any memory may provide volatile or non-volatile retention of information. Furthermore, any memory may represent a fixed or removable component of the computer device 2002. In one embodiment, when the processor 2004 executes associated instructions stored in any memory or combination of memories, the computer device 2002 may perform any operation of the associated instructions. The computer device 2002 also includes one or more drive mechanisms 2008, such as a hard disk drive mechanism, an optical disk drive mechanism, etc., for interacting with any memory.

[0181] The computer device 2002 may further include an input / output module 2010 (I / O) for receiving various inputs (via input devices 2012) and for providing various outputs (via output devices 2014). A specific output mechanism may include a presentation device 2016 and an associated graphical user interface (GUI) 2018. In other embodiments, the input / output module 2010 (I / O), input devices 2012, and output devices 2014 may not be included, and the computer device 2002 may simply serve as a computer device in a network. The computer device 2002 may further include one or more network interfaces 2020 for exchanging data with other devices via one or more communication links 2022. One or more communication buses 2024 couple the components described above together.

[0182] The communication link 2022 may be implemented in any manner, for example, via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 2022 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0183] Corresponding to Figures 1 to 8 The method in this specification also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the above method are executed.

[0184] The embodiment of this specification also provides a computer-readable instruction, wherein when the processor executes the instruction, the program therein causes the processor to execute the following Figures 1 to 8 The method shown.

[0185] It should be understood that in the various embodiments of this specification, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0186] It should also be understood that in the embodiments of this specification, the term "and / or" is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " in this specification generally indicates that the associated objects are in an "or" relationship.

[0187] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the embodiments of this specification can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of this specification.

[0188] Those skilled in the art will clearly understand that, for the sake of convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0189] In the several embodiments provided in this specification, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or can be an electrical, mechanical or other form of connection.

[0190] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of this specification.

[0191] In addition, the functional units in the various embodiments of this specification may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0192] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of this specification is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of this specification. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0193] Specific embodiments are used in this specification to illustrate the principles and implementation methods of this specification. The description of the above embodiments is only used to help understand the methods and core ideas of the embodiments of the specification. At the same time, for those skilled in the art, based on the ideas of the embodiments of this specification, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the embodiments of this specification.

Claims

1. A method for determining the first collision source for shielding calculation, characterized in that: The method comprises: Acquiring information about a source item of emitted particles and information about a preset first collision point of the particles, wherein the preset first collision point represents a position where the particles first collide with a substance during transport; Determining one or more geometric models for representing the area passed by the particle when the particle reaches the preset first collision point; The travel distance of the particle in each of the geometric models is calculated, and a first collision source corresponding to a preset first collision point is determined according to the travel distance and material information corresponding to each of the geometric models.

2. The method according to claim 1, wherein Before obtaining the information of the source item of the emitted particles and the information of the first collision point preset by the particles, it also includes: Constructing a total grid area including a preset first collision point and the source term; Generating a set of geometric models corresponding to the total grid area; Determining the grid area that each computing core is responsible for based on each computing core and the total grid area; The source item information, the geometric model set and the corresponding material information, and the grid area that each computing core is responsible for are sent to the corresponding computing core.

3. The method according to claim 2, wherein Calculating the travel distance of the particle in each of the geometric models, including: Determining the entry and exit positions of the particles in each of the geometric models according to the information of the source term and the information of the preset first collision point; Each computing core calculates in parallel the travel distances of the particle corresponding to different first collision points based on the penetration position and the exit position.

4. The method according to claim 1, wherein Determining a first collision source corresponding to a preset first collision point according to the travel distance and material information corresponding to each of the geometric models includes: Determining the total travel distance of the particles corresponding to the same material information according to the travel distance of the particles in each of the geometric models; Get the total cross section of the geometric model corresponding to the same material information; Determining the optical distance of the particle based on the total travel distance and total cross-section of the particle in different materials; A first collision source corresponding to a preset first collision point is determined according to the optical distance.

5. The method according to claim 1, wherein The method further comprises: Get information about reflection boundaries; Constructing a virtual source term that takes the reflection boundary as the symmetry axis and is symmetrical to the source term; Determining, based on the virtual source term and the preset first collision point, an intersection point between a travel path of an emitted particle of the virtual source term and the reflection boundary; The travel distance of the emitted particles of the virtual source item in each of the geometric models is determined according to the area through which the emitted particles of the source item pass when reaching the preset first collision point via the intersection point after being emitted.

6. The method according to claim 2, wherein The method further comprises: Determining an encryption threshold according to a preset grid refinement factor and a particle travel distance between a source term and the preset first collision point; Encrypt the grid in the grid area where the source item is located according to the encryption threshold; A first collision source corresponding to a preset first collision point is determined according to the travel distance, the grid of the grid area where the source item is located, and material information.

7. The method according to claim 6, wherein The mesh in the source area is refined based on the refinement threshold, including: Determine whether the size of the grid in the grid area where the source item is located is greater than the encryption threshold; If the answer is yes, recursively encrypt the grid in the grid area where the source item is located.

8. The method according to claim 7, wherein Recursively refine the grid in the source area, including: Divide the grid in the grid area where the source item is located into subgrids; Calculating the distance between the center of the sub-grid and the preset first collision point; Updating the encryption threshold according to a preset grid refinement factor and a distance between the center of the subgrid and the preset first collision point; When the size of a subgrid is larger than the updated encryption threshold, the subgrid is sub-grid-divided, and the sub-grid division operation according to the encryption threshold is continuously performed until the number of divisions reaches the preset grid division threshold.

9. A first collision source determination device for shielding calculation, characterized in that: The device comprises: an acquisition module, configured to acquire information about a source item of emitted particles and information about a preset first collision point of the particles, wherein the preset first collision point represents a position where the particles first collide with a substance during transport; A first determining module is used to determine one or more geometric models for representing the area passed by the particle when reaching the preset first collision point; The second determining module is used to calculate the travel distance of the particle in each of the geometric models, and determine the first collision source corresponding to the preset first collision point according to the travel distance and the material information corresponding to each of the geometric models.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

11. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor of a computer device, the method according to any one of claims 1 to 8 is implemented.

12. A computer program product, comprising a computer program, characterized in that: When the computer program is executed by a processor of a computer device, the method according to any one of claims 1 to 8 is implemented.

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