Radiation heat flow calculation-oriented self-adaptive grid division method and radiation heat flow calculation-oriented self-adaptive grid division device

Abstract

The invention provides a radiation heat flow calculation-oriented adaptive grid division method and device, and relates to the technical field of thermal radiation performance simulation. Comprising the following steps: carrying out grid division on each component in a spacecraft geometric model; according to the direction of each energy beam emitted by the spacecraft, the mutual vision relation between the component grids is judged; for the units with mutual vision in the grid, determining a shielding relationship among the units in the grid; if the shielded unit is smaller than the shielding threshold value, grid division is ended; if the sheltered units are higher than the sheltering threshold value, grid division is carried out on the sheltered units, the operation is repeated and iterated until all the sheltered units are smaller than the sheltering threshold value, iteration is stopped, and the spacecraft grid model is obtained. Thus, intelligent self-adaptive mesh generation is performed on the spacecraft geometric model, accurate positioning and mesh refinement of the shielding shadow are realized, and the calculated amount is reduced and convergence becomes fast along with the improvement of the accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of thermal radiation performance simulation, and in particular to an adaptive grid division method and device for radiation heat flow calculation. Background Art

[0002] Thermal radiation is the phenomenon that matter radiates heat energy outward in the form of electromagnetic waves. Any object will transfer heat to the outside world in the form of thermal radiation as long as its temperature is higher than absolute zero (-273.15℃ or 0K). Thermal radiation is widely used in daily life, industrial production and scientific research.

[0003] Take the heat flux from outer space to which a spacecraft is subjected as an example: the heat flux from outer space is the main external factor affecting the temperature of an on-orbit spacecraft. Since the orbit of a spacecraft may have a shadow of the earth, when the spacecraft enters the shadow, it loses the direct solar radiation, which is the main heat flux from outer space, and the temperature drops sharply. When it leaves the shadow, it receives direct solar radiation, and the temperature rises sharply. The huge temperature difference will form a thermal shock, affecting the internal precision instruments of the spacecraft, and thus affecting the health of the on-orbit spacecraft. Therefore, thermal analysis of spacecraft is crucial.

[0004] At present, the calculation method of radiation heat flux is usually to use the Monte Carlo method. The Monte Carlo method decomposes the radiation source light into several rays and divides the radiated body into grids; by calculating the ratio of the number of radiation rays falling on the radiator unit to the total number of radiation rays, the heat flux density of the radiated unit is finally calculated. The calculation process of the Monte Carlo method is simple and can handle complex geometric shapes and occlusion problems, but as the number of simulated beams increases, the calculation amount of the Monte Carlo method increases dramatically, the convergence slows down, and the time consumed increases dramatically. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide an adaptive grid division method and device for radiation heat flow calculation, so as to solve the problem that the calculation amount of the traditional Monte Carlo method increases sharply and the convergence slows down as the calculation accuracy increases.

[0006] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of the present invention provides an adaptive grid generation method for radiation heat flow calculation, comprising:

[0008] Mesh each component in the spacecraft geometric model to obtain the first layer of mesh;

[0009] According to the directions of the energy beams emitted by the spacecraft, the mutual visibility relationship between the cells in the first layer of grid is determined, and the cells with mutual visibility and the cells without mutual visibility are recorded;

[0010] Divide the cells with mutual visibility into grids to obtain the second layer of grids;

[0011] According to the energy beam emission point position of each unit in the second layer grid, determine the occlusion relationship between the units in the second layer grid, and mark the occluded units and the unoccluded units;

[0012] Determine whether the occluded unit is smaller than the occlusion threshold. If so, end the grid division. If not, grid the occluded unit to obtain the third-layer grid, update the second-layer grid to the third-layer grid, return to the step of determining the occlusion relationship between the units in the second-layer grid according to the energy beam emission position of each unit in the second-layer grid, and mark the occluded unit and the unoccluded unit, until all the occluded units are smaller than the occlusion threshold, stop the iteration, and obtain the latest layer of grid;

[0013] The cells without mutual view and the unobstructed cells use the first layer of mesh, and the obstructed cells use the latest layer of mesh to obtain the spacecraft mesh model.

[0014] A second aspect of the present invention provides an adaptive grid generation device for radiation heat flow calculation, comprising:

[0015] The first partitioning module is used to perform mesh partitioning on each component in the spacecraft geometric model to obtain a first layer of mesh;

[0016] A mutual visibility relationship determination module is used to determine the mutual visibility relationship between the units in the first layer of grids according to the directions of the energy beams emitted by the spacecraft, and record the units with mutual visibility and the units without mutual visibility;

[0017] The second division module is used to divide the cells with mutual visibility into grids to obtain a second layer of grids;

[0018] An occlusion relationship determination module is used to determine the occlusion relationship between the units in the second layer of grids according to the energy beam emission point positions of the units in the second layer of grids, and mark the occluded units and the unoccluded units;

[0019] A judgment module is used to judge whether the occluded unit is smaller than the occlusion threshold. If so, the grid division is terminated. If not, the occluded unit is grid-divided to obtain a third-layer grid, the second-layer grid is updated to the third-layer grid, and the occlusion relationship between the units in the second-layer grid is determined according to the energy beam emission position of each unit in the second-layer grid, and the steps of marking the occluded unit and the unoccluded unit are stopped until all the occluded units are smaller than the occlusion threshold, and the latest layer grid is obtained;

[0020] Using the module, the first layer of mesh is used for cells without mutual view and unoccluded cells, and the latest layer of mesh is used for occluded cells to obtain the spacecraft mesh model.

[0021] Compared with the prior art, the present invention provides an adaptive grid division method and device for radiation heat flux calculation, which divides the components in the spacecraft geometric model into grids to obtain a first-layer grid; determines the mutual visibility relationship between the units in the first-layer grid according to the directions of the energy beams emitted by the spacecraft, and records the units with mutual visibility and the units without mutual visibility; divides the units with mutual visibility into grids to obtain a second-layer grid; determines the occlusion relationship between the units in the second-layer grid according to the positions of the energy beam emission points of the units in the second-layer grid, and marks the occluded units and the unoccluded units; and determines the occluded units. Whether the blocking unit is smaller than the occlusion threshold, if so, the meshing is terminated, if not, the blocked unit is meshed to obtain the third-layer mesh, the second-layer mesh is updated to the third-layer mesh, and the energy beam emission position of each unit in the second-layer mesh is returned to determine the occlusion relationship between each unit in the second-layer mesh, and the steps of marking the blocked units and the unblocked units are marked until all blocked units are smaller than the occlusion threshold, and the iteration is stopped to obtain the latest layer of mesh; the units without mutual visibility and the unblocked units use the first layer of mesh, and the blocked units use the latest layer of mesh to obtain the spacecraft mesh model. In this way, the spacecraft geometric model is intelligently and adaptively meshed, and the blocked units and the unblocked units in the mesh are identified layer by layer, and the blocked units are adaptively and layer by layer. The units without mutual visibility are meshed only once, and the unblocked units under the units with mutual visibility are eliminated step by step, so as to achieve the precise positioning of the blocking shadow and mesh refinement, so that the amount of calculation is reduced and the convergence is faster as the accuracy is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By reading the detailed description below with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0023] Figure 1 A flowchart of an adaptive meshing method for radiation heat flow calculation is schematically shown;

[0024] Figure 2 The schematic diagram of the occlusion judgment principle is shown;

[0025] Figure 3 The iterative meshing flow chart of the adaptive meshing method for radiation heat flow calculation is schematically shown;

[0026] Figure 4 A diagram schematically shows the relationship between the occlusion threshold and the calculated heat flow;

[0027] Figure 5The schematic diagram of the spatial heat flow calculated by the grid-adaptive Monte Carlo method is shown schematically;

[0028] Figure 6 The schematic diagram of dividing the spacecraft geometric model into grids layer by layer according to an embodiment of the present invention is schematically shown;

[0029] Figure 7 A schematic diagram of a spacecraft grid model is shown schematically;

[0030] Figure 8 The structure diagram of the adaptive grid division device for radiation heat flow calculation is schematically shown. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0032] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present invention should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0033] The method in the embodiment of the present invention is described in detail below.

[0034] Figure 1 The flowchart of the adaptive grid division method for radiation heat flow calculation in the embodiment of the present invention is schematically shown. Figure 1 As shown, the adaptive grid division method for radiation heat flow calculation may include:

[0035] S101. Mesh each component in the spacecraft geometric model to obtain a first-layer mesh.

[0036] Specifically, for the transition area in each component, a triangular mesh is used for mesh division, and for the area except the transition area in each component, a quadrilateral mesh is used for mesh division.

[0037] The main function of the first layer of grid is to describe the boundary of the spacecraft geometric model, so it is the coarse grid layer L0.

[0038] Specifically, after meshing the components in the spacecraft geometric model to obtain the first layer of meshes, the following steps are also included:

[0039] Step A1: Determine the direction of sunlight according to the orbit and attitude of the spacecraft.

[0040] Specifically, before determining the direction of sunlight according to the orbital position and attitude of the spacecraft, it also includes: determining the operating orbit of the spacecraft according to the six elements of the orbit.

[0041] The six elements of an orbit include the semi-major axis, orbital eccentricity, orbital plane inclination, right ascension of the ascending node, argument of perigee and time of passing perigee.

[0042] The present invention takes the geosynchronous orbit as an example, the X-axis of the spacecraft is the running direction, and the Z-axis is perpendicular to the XOY plane and points upward.

[0043] Step A2: The direction opposite to the direction of sunlight and perpendicular to the surface of each component is determined as the direction of each energy beam emitted by the spacecraft.

[0044] S102. Determine the mutual visibility relationship between the units in the first layer of grids according to the directions of the energy beams emitted by the spacecraft, and record the units with mutual visibility and the units without mutual visibility.

[0045] The reason for mutual visibility judgment is that some surfaces are visible to each other due to the characteristics of the spacecraft structure. The mutually visible surfaces may be blocked, and the blocked parts will not be exposed to the heat flow outside the space. Therefore, after the grid is divided, it is necessary to first determine the mutual visibility relationship between the units in the first layer of the grid. Further determine the blocking relationship between two units.

[0046] Determine the mutual visibility relationship between the units in the first layer of the grid. Occlusion will occur only for the units with mutual visibility. Therefore, occlusion is only calculated for the units with mutual visibility. The mutual visibility relationship between the units in the first layer of the grid is determined as follows:

[0047] Assume that the energy beam emission points of unit x and unit y in the first layer of grid are P x and P y , where the external normal direction vectors of unit x and unit y in the first layer of grid are and Then we have:

[0048]

[0049]

[0050] in, Indicates that the starting point is the energy beam emission point P of unit x in the first layer of the grid x , the end point is the energy beam emission point P of unit y in the first layer of grid y The vector of Represents the external normal direction vector of unit y in the first layer of the grid The modulus value of .

[0051] If the cells x and y in the first layer of the grid satisfy formula (1) and formula (2), it means that the cells x and y have a mutual visibility relationship.

[0052] S103, meshing the cells with mutual visibility to obtain a second layer of meshes.

[0053] The cells with mutual visibility are meshed finely, and the second-layer mesh is K times finer than the first-layer mesh (K=4 in the embodiment), to obtain the second-layer mesh L1, in which each cell emits an energy beam outward.

[0054] The direction in which each unit in the second layer of grid emits an energy beam is opposite to the direction of sunlight and perpendicular to the surface of each component.

[0055] S104, determining the shielding relationship between the units in the second layer of grids according to the energy beam emission point positions of the units in the second layer of grids, and marking shielded units and unshielded units.

[0056] According to the energy beam emission point position of each unit in the second layer grid, the occlusion relationship between each unit in the second layer grid is determined, as follows:

[0057] Assume that a cell E in the second-layer grid of the spacecraft geometry model s The three vertices are I, J, and M, and the center is O. m , computing unit O in the second layer grid r The normal vector is The energy beam emission point is O e (x e ,y e ,z e ), the geocentric coordinate is O E (x E ,y E ,z E ), the radius of the earth is R.

[0058] Computing Unit O r With unit E s The judgment formula is:

[0059]

[0060] in, The calculation unit O r With unit E s The angle of the energy beam.

[0061] Geocentric E To four rays The distance d N for:

[0062]

[0063] In order to exclude the distance from the center of the earth to the reverse extension line of the ray from satisfying the above formula, the following judgment is made:

[0064]

[0065] in, O E To computing unit O r With computing unit O r To Unit E s The energy beam angle.

[0066] If the center of the earth E If the positional relationship with any of the four rays satisfies formula (3), formula (4) and formula (5) at the same time, it means that there is an occlusion relationship between the two units in the second layer grid.

[0067] Figure 2 The schematic diagram of the occlusion judgment principle is shown. Figure 2 The medium orange is the blocked part of the spacecraft geometric model, the gray is the unblocked part, i.e. the unblocked unit, the red arrow is the direction of sunlight, the direction of the energy beam is the opposite of the direction of sunlight and is perpendicular to the surface of the object, i.e. the component. If they intersect, it is blocked, otherwise it is not blocked.

[0068] S105, determine whether the occluded unit is smaller than the occlusion threshold, if so, end the grid division, if not, grid the occluded unit to obtain the third layer grid, update the second layer grid to the third layer grid, return to the step of determining the occlusion relationship between the units in the second layer grid according to the energy beam emission position of each unit in the second layer grid, marking the occluded units and the unoccluded units, and stop the iteration when all the occluded units are smaller than the occlusion threshold to obtain the latest layer grid.

[0069] The condition for stopping iteration includes not only the condition that all the occluded units are smaller than the occlusion threshold, but also the condition that the number of iterations reaches a preset number.

[0070] Determine whether the occluded unit is smaller than the occlusion threshold. If so, end the grid division. If not, grid the occluded unit to obtain the third layer of grids, update the second layer of grids to the third layer of grids, and return to execute step S104 until all occluded units are smaller than the occlusion threshold, or the iteration number reaches the preset number and stops the iteration to obtain the latest layer of grids.

[0071] Specifically, the expression of the occlusion threshold is:

[0072]

[0073] in, is the occlusion threshold, St is the area of ​​each unit in each layer of the grid, S T is the surface area of ​​each component.

[0074] Specifically, the occlusion threshold is less than 0.01.

[0075] Figure 3 The iterative meshing flow chart of the adaptive meshing method for radiation heat flux calculation is shown schematically. Figure 3 As shown, the spacecraft geometric model is divided into a coarse grid layer L0, and the mutual visibility relationship of the components is determined. When the components do not see each other, the components without mutual visibility, that is, the units without mutual visibility, are recorded. When the components see each other, if it is the first round of iteration (i=0), the grid of the units with mutual visibility is refined as a whole. If it is an iteration greater than the first round (i>0), only the grid of the blocked units is refined K times. It is necessary to determine the occlusion relationship between the units in the grid. If there is no occlusion relationship between the units, the unblocked units are recorded. If there is an occlusion relationship between the units, the blocked units are marked. , determine whether the obscured unit is smaller than the occlusion threshold. If the obscured unit is smaller than the occlusion threshold, record the obscured unit and end the grid division. If the obscured unit is not smaller than the occlusion threshold, perform the next round of iteration (let i=i+1), return to the step of determining whether i is greater than 0, continue to determine the occlusion relationship between the units in the grid, stop iteration when all obscured units are smaller than the occlusion threshold, and obtain the latest layer of grid L. The unobstructed units use the coarse grid layer L0, and the obscured units use the latest layer of grid L. Then, the heat load of the radiated body is calculated and the entire operation is ended.

[0076] The grid of the present invention is an adaptive grid division, specifically refers to improving the computational efficiency by reducing the variance, and dividing the grid of the spacecraft geometric model into layers 0 to L according to the degree of refinement. The target value expectation is estimated by combining the grids of different layers of the model, thereby reducing the variance and improving the computational efficiency.

[0077] The present invention significantly reduces the amount of calculation and improves the calculation efficiency while ensuring the calculation accuracy. The focus is on the intelligent adaptive meshing of the spacecraft geometric model. By identifying the obscured units and unobscured units in the mesh layer by layer, the mesh of the obscured units is adaptively encrypted layer by layer, thereby achieving accurate positioning of the obscured shadows and mesh refinement. The present invention solves the problem that when the Monte Carlo method is used to calculate the thermal radiation heat flux density, the amount of calculation increases dramatically with the improvement of accuracy and the convergence deteriorates significantly.

[0078] S106. The cells without mutual visibility and the unobstructed cells use the first layer of grids, and the obstructed cells use the latest layer of grids to obtain a spacecraft grid model.

[0079] Specifically, after the cells without mutual visibility and the unobstructed cells use the first layer of grids and the obstructed cells use the latest layer of grids to obtain the spacecraft grid model, the method further includes:

[0080] Step B1: Determine the actual heat flux according to the heat flux density and the actual shaded unit.

[0081] Step B2: Determine and calculate the heat flux based on the surface area and heat flux density of the blocked unit and each component.

[0082] Specifically, Figure 4 The relationship between the occlusion threshold and the calculated heat flux is shown schematically. The horizontal axis is the ratio of the actual heat flux to the calculated heat flux, and the vertical axis is the inverse of the occlusion threshold. The blue line is an on-orbit spacecraft with an angle of 15°, the green line is an on-orbit spacecraft with an angle of 30°, the cyan line is an on-orbit spacecraft with an angle of 45°, and the purple line is an on-orbit spacecraft with an angle of 55°. For spacecraft on orbit at any angle, that is, no matter what the angle of the on-orbit spacecraft is, when the ratio of the area of ​​each unit in each grid layer to the surface area of ​​each component is 0.01, that is, the surface area of ​​each component / the area of ​​each unit in each grid layer is 100, the actual heat flux tends to be consistent with the calculated heat flux, and thus the occlusion threshold should be less than 0.01.

[0083] Figure 5 The schematic diagram of the extra-spatial heat flow calculated by the grid-adaptive Monte Carlo method is shown schematically, specifically, a diagram of the change in total heat jet density during one operating cycle of the satellite orbit. The horizontal axis is time, and the vertical axis is the total heat jet density. The extra-spatial heat flow includes actual heat flow and calculated heat flow.

[0084] The expression for the actual heat flow is:

[0085] Q a =qS a ;

[0086] The expression for calculating heat flow is:

[0087]

[0088] Among them, Q a is the actual heat flow, q is the heat flux density, S a is the actual blocked unit area, Q c To calculate the heat flow, S T is the surface area of ​​each component, S ci is the area of ​​the blocked unit divided in the i-th iteration, and n is the number of blocked units.

[0089] Combining grid layers of different levels for calculation can achieve high accuracy and fast calculation speed, or higher accuracy at the same calculation speed.

[0090] The spacecraft grid model finally obtained is a grid model of adaptive size, that is, the grid in the unobstructed area is coarse, which is convenient for rapid calculation, and the grid in the obstructed part is dense, which obtains accurate results. The present invention solves the problem that the calculation amount of the traditional Monte Carlo method increases sharply with the improvement of calculation accuracy.

[0091] Example: The spacecraft geometry model is divided into 4 levels (L=3), and the quadrilateral mesh of each level is 4 times finer than that of the previous level. Figure 6 The schematic diagram of dividing the spacecraft geometric model into grids layer by layer according to an embodiment of the present invention is schematically shown, wherein: Figure 6 (a) is a schematic diagram of the coarse grid layer division. Specifically, each component in the spacecraft geometric model is grid-divided to obtain the coarse grid layer L0, that is, the layer corresponding to L = 0, to determine the mutual visibility relationship between the components of the spacecraft geometric model, and to record the units with mutual visibility and the units without mutual visibility. Figure 6 (b) is a schematic diagram of meshing components with mutual visibility. Specifically, meshing is performed on units with mutual visibility, which is refined K times to obtain the second-layer mesh L1, that is, the layer corresponding to L=1. It is then calculated whether occlusion occurs between units in the second-layer mesh L1, and the occluded units and unoccluded units are marked. Figure 6 (c) is a schematic diagram of meshing the occluded unit. Specifically, the occluded unit is compared with the occlusion threshold. If the occluded unit is larger than the occlusion threshold, the occluded unit is meshed and refined K times to obtain a new occlusion mesh, i.e., the third layer mesh L2, which is the layer corresponding to L=2. Figure 6 (d) is a schematic diagram of meshing the obscured units in the third layer of grids. When the obscured units are larger than the occlusion threshold, the obscured units in the third layer of grids are meshed and refined K times to obtain the fourth layer of grids L3, that is, the layer corresponding to L=3. The obscured units in the fourth layer of grids are smaller than the occlusion threshold, and the mesh refinement ends. Comprehensively considering the grids of each layer, in this embodiment, the L that meets the occlusion threshold is the fourth layer of grids, that is, the four layers of grids L0, L1, L2, and L3. The unobstructed units are calculated using the coarse grid layer L0, and the obscured units are calculated using the high-level grid L3. The outer heat flow of the space is calculated by combining the coarse grid layer and the highest grid layer, which not only ensures the accuracy of the calculation but also solves the problems of increased calculation amount and slow convergence. The above-mentioned meshing refers to dividing the spacecraft geometric model into discrete grids. The original strength mainly adopts the quadrilateral grid division model, and the transition area uses the triangular grid. This embodiment can both describe the boundary surface of the spacecraft and become the calculation unit for subsequent occlusion judgment.

[0092] Figure 7 A schematic diagram of the spacecraft grid model is shown schematically, see Figure 7As shown, this is the final mesh of the spacecraft geometric model. It can be seen that the cells without mutual visibility and the unobstructed cells use the first layer of mesh, and the obstructed cells use the latest layer of mesh.

[0093] Based on the above Figure 1 It can be seen from the implementation method that the embodiment of the present invention meshes the components in the spacecraft geometric model to obtain the first layer of meshes; determines the mutual visibility relationship between the units in the first layer of meshes according to the directions of the energy beams emitted by the spacecraft, and records the units with mutual visibility and the units without mutual visibility; meshes the units with mutual visibility to obtain the second layer of meshes; determines the occlusion relationship between the units in the second layer of meshes according to the energy beam emission point positions of the units in the second layer of meshes, and marks the occluded units and the unoccluded units; and determines whether the occluded unit is smaller than the occlusion threshold If yes, meshing is terminated. If not, meshing is performed on the obscured cells to obtain the third-layer mesh, and the second-layer mesh is updated to the third-layer mesh. The steps of determining the occlusion relationship between the cells in the second-layer mesh according to the energy beam emission position of each cell in the second-layer mesh, and marking the obscured cells and the unobstructed cells are returned until all obscured cells are less than the occlusion threshold, and the iteration is stopped to obtain the latest layer of mesh; the cells without mutual visibility and the unobstructed cells use the first layer of mesh, and the obscured cells use the latest layer of mesh to obtain the spacecraft mesh model. In this way, the spacecraft geometric model is intelligently and adaptively meshed. By identifying the obscured cells and the unobstructed cells in the mesh layer by layer, the obscured cells are adaptively and layer by layer, and the cells without mutual visibility are meshed only once. The unobstructed cells under the cells with mutual visibility are eliminated step by step, so as to achieve the precise positioning of the obstructed shadows and mesh refinement, so that the amount of calculation is reduced and the convergence is faster as the accuracy is improved.

[0094] Based on the same inventive concept, as an implementation of the above-mentioned adaptive meshing method for radiation heat flux calculation, an embodiment of the present invention further provides an adaptive meshing device for radiation heat flux calculation. Figure 8 FIG. 1 is a structural diagram of an adaptive grid division device for radiation heat flow calculation in an embodiment of the present invention, see Figure 8 As shown, the device may include:

[0095] The first division module 801 is used to divide the components in the spacecraft geometric model into grids to obtain a first layer of grids;

[0096] The mutual visibility relationship determination module 802 is used to determine the mutual visibility relationship between the units in the first layer of grids according to the directions of the energy beams emitted by the spacecraft, and record the units with mutual visibility and the units without mutual visibility;

[0097] The second division module 803 is used to divide the cells with mutual visibility into grids to obtain a second layer of grids;

[0098] The occlusion relationship determination module 804 is used to determine the occlusion relationship between the units in the second layer of grids according to the energy beam emission point positions of the units in the second layer of grids, and mark the occluded units and the unoccluded units;

[0099] The judgment module 805 is used to judge whether the blocked unit is smaller than the blocking threshold. If so, the grid division is terminated. If not, the blocked unit is grid-divided to obtain a third-layer grid, and the second-layer grid is updated to the third-layer grid. The blockage relationship between the units in the second-layer grid is determined according to the energy beam emission position of each unit in the second-layer grid, and the steps of marking the blocked units and the unblocked units are stopped until all the blocked units are smaller than the blocking threshold, and the latest layer grid is obtained.

[0100] Using module 806, the first layer grid is used for cells without mutual view and unobstructed cells, and the latest layer grid is used for obstructed cells to obtain the spacecraft grid model.

[0101] The device may also include: a first determination module, used to determine the direction of sunlight exposure according to the spacecraft's orbit and attitude after meshing the components in the spacecraft's geometric model to obtain the first layer of meshes; a second determination module, used to determine the direction opposite to the direction of sunlight exposure and perpendicular to the surface of each component as the direction of each energy beam emitted by the spacecraft.

[0102] In the judgment module 805, the expression of the occlusion threshold is:

[0103]

[0104] in, is the occlusion threshold, 2 t is the area of ​​each unit in each layer of the grid, S T is the surface area of ​​each component.

[0105] The device may also include: a third determination module, which is used to use the first layer of grids for units without mutual visibility and unobstructed units, and the latest layer of grids for obstructed units to obtain a spacecraft grid model, and then determine the actual heat flux according to the heat flux density and the actual obstructed units; a fourth determination module, which is used to determine the calculated heat flux according to the surface area and heat flux density of the obstructed units and components.

[0106] It should be pointed out here that the above description of the embodiment of the adaptive meshing device for radiation heat flow calculation is similar to the description of the embodiment of the adaptive meshing method for radiation heat flow calculation, and has similar beneficial effects as the embodiment of the adaptive meshing method for radiation heat flow calculation. For technical details not disclosed in the embodiment of the adaptive meshing device for radiation heat flow calculation of the embodiment of the present invention, please refer to the description of the embodiment of the adaptive meshing method for radiation heat flow calculation of the present invention for understanding.

[0107] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An adaptive grid generation method for radiation heat flux calculation, characterized in that: include: Mesh each component in the spacecraft geometric model to obtain the first layer of mesh; According to the directions of the energy beams emitted by the spacecraft, the mutual visibility relationship between the units in the first layer of grids is determined, and the units with mutual visibility and the units without mutual visibility are recorded; Dividing the cells with mutual visibility into grids to obtain a second layer of grids; Determine the shielding relationship between the units in the second layer of grids according to the positions of the energy beam emission points of the units in the second layer of grids, and mark the shielded units and the unshielded units; Determine whether the blocked unit is smaller than the blocking threshold, if so, end the grid division, if not, grid the blocked unit to obtain a third-layer grid, update the second-layer grid to the third-layer grid, return to the step of determining the blocking relationship between the units in the second-layer grid according to the energy beam emission position of each unit in the second-layer grid, and mark the blocked units and the unblocked units, until all blocked units are smaller than the blocking threshold, stop iteration, and obtain the latest layer grid; The cells without mutual visibility and the unblocked cells use the first layer of grids, and the blocked cells use the latest layer of grids, so as to obtain a spacecraft grid model.

2. The adaptive grid generation method for radiation heat flow calculation according to claim 1 is characterized in that: For the transition area in each component, a triangular mesh is used for mesh division, and for the area in each component except the transition area, a quadrilateral mesh is used for mesh division.

3. The adaptive grid generation method for radiation heat flow calculation according to claim 1, characterized in that: After meshing the components in the spacecraft geometric model to obtain a first layer of meshes, the method further includes: Determine the direction of sunlight according to the orbit and attitude of the spacecraft; The direction opposite to the sunlight irradiation direction and perpendicular to the surface of each component is determined as the direction of each energy beam emitted by the spacecraft.

4. The adaptive grid generation method for radiation heat flow calculation according to claim 3 is characterized in that: Before determining the sunlight irradiation direction according to the orbital position and the attitude of the spacecraft, the method further includes: The operating orbit of the spacecraft is determined based on the six elements of the orbit.

5. The adaptive grid generation method for radiation heat flow calculation according to claim 1, characterized in that: The expression of the occlusion threshold is: in, is the occlusion threshold, S t is the area of ​​each unit in each layer of the grid, S T is the surface area of ​​each component.

6. The adaptive grid generation method for radiation heat flow calculation according to claim 5, characterized in that: The occlusion threshold is less than 0.

01.

7. The adaptive grid generation method for radiation heat flow calculation according to claim 1, characterized in that: After the cells without mutual visibility and the unobstructed cells use the first layer of grids, and the obstructed cells use the latest layer of grids to obtain a spacecraft grid model, the method further includes: Determine the actual heat flux based on the heat flux density and the actual shaded unit; The heat flux is determined and calculated according to the surface areas of the blocked unit and the components and the heat flux density.

8. The adaptive grid generation method for radiation heat flow calculation according to claim 7, characterized in that: The actual heat flow expression is: Q a =qS a ; The expression for calculating the heat flow is: Among them, Q a is the actual heat flow, q is the heat flux density, S a is the actual blocked unit area, Q c Calculate the heat flow for the T is the surface area of ​​each component, S ci is the area of ​​the occluded unit divided in the i-th iteration, and n is the number of occluded units.

9. An adaptive grid generation device for radiation heat flow calculation, characterized in that: include: The first partitioning module is used to perform mesh partitioning on each component in the spacecraft geometric model to obtain a first layer of mesh; A mutual visibility relationship determination module, used to determine the mutual visibility relationship between the units in the first layer of grids according to the directions of the energy beams emitted by the spacecraft, and record the units with mutual visibility and the units without mutual visibility; A second division module is used to divide the cells with mutual visibility into grids to obtain a second layer of grids; An occlusion relationship determination module, used to determine the occlusion relationship between the units in the second layer of grids according to the energy beam emission point positions of the units in the second layer of grids, and mark the occluded units and the unoccluded units; A judgment module, used to judge whether the obscured unit is smaller than an obscuration threshold, if so, terminate the grid division, if not, perform grid division on the obscured unit to obtain a third-layer grid, update the second-layer grid to the third-layer grid, return to the step of determining the obscuration relationship between the units in the second-layer grid according to the energy beam emission position of each unit in the second-layer grid, and marking the obscured unit and the unobscured unit, until all obscured units are smaller than the obscuration threshold, and stop iteration to obtain the latest layer grid; Using the module, the first layer grid is used for the cells without mutual visibility and the unobstructed cells, and the latest layer grid is used for the obstructed cells, so as to obtain the spacecraft grid model.

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