Thermal radiation simulation analysis method and system for indoor fire of chemical plant building

Abstract

The invention discloses a thermal radiation simulation analysis method and system for an indoor fire of a chemical plant building, and belongs to the technical field of industrial fire safety, and the method comprises the following steps: building a model; highly layering; radiation calculation; danger grading; and performing visual display. According to the invention, highly layered discretization is carried out on an indoor space, a layered radiation calculation model is established, and a Unity 3D three-dimensional visualization platform is combined, so that the thermal radiation intensity distribution is superposed in a real building model in a cloud picture form, thereby dynamically displaying the change of a thermal radiation hazard area in a fire spreading process, and improving the fire hazard hazard effect. Scientific support is provided for evacuation path optimization, fireman safe operation area delimiting and emergency rescue decision making.

Description

Technical Field

[0001] This invention relates to the field of industrial fire safety technology, specifically to a method and system for simulating and analyzing thermal radiation in indoor fires in chemical plant buildings. Background Technology

[0002] Chemical plants, as typical high-risk production sites, generally contain large quantities of flammable, explosive, and toxic chemicals. A fire in such a plant can cause not only enormous economic losses but also trigger a series of explosions or environmental pollution, posing a serious threat to human life and public safety. The internal spaces of chemical plant buildings are typically complex and densely packed with equipment, leading to rapid fire spread and high thermal radiation intensity. Traditional fire assessment methods struggle to accurately describe the dynamic distribution of heat transfer within the fire zone. Currently, fire thermal radiation analysis methods mainly fall into two categories: one is refined numerical simulation based on computational fluid dynamics (CFD), and the other is simplified calculation methods based on empirical or semi-empirical models. While CFD models can accurately describe the temperature, velocity, and radiation fields in a fire, they are computationally intensive, time-consuming, and complex to build, making them unsuitable for rapid analysis and real-time prediction. Simplified models, on the other hand, offer advantages such as fast calculation speed and readily available parameters in engineering applications, and are therefore widely used in fire safety assessments.

[0003] Among numerous simplified models, the point source radiation model is widely used for fire radiation hazard analysis due to its high computational efficiency and simple form. This model treats the fire source as several radiation point sources and estimates the thermal radiation impact of a fire on surrounding objects or personnel by calculating the attenuation of radiation intensity with distance and direction. However, when applied to the complex indoor environment of chemical plants, traditional point source models often fail to adequately consider factors such as spatial stratification, equipment shielding effects, and smoke absorption attenuation, making it difficult to accurately reflect the spatiotemporal distribution of thermal radiation at different height levels.

[0004] Chemical plant buildings typically feature multi-level operating platforms, dense equipment layouts, and complex spatial structures, resulting in significant differences in thermal radiation at different height levels after a fire. To more realistically depict the spatial distribution characteristics of fire thermal radiation, it is necessary to introduce a height-layered discretization method based on the point source model to perform layered calculations and heat flux distribution analysis of the indoor space. Simultaneously, by combining modern 3D visualization technology, the calculation results can be overlaid onto the building model in real time as a thermal radiation cloud map, achieving a dynamic and visual representation of fire radiation hazards. Addressing the challenges of balancing computational efficiency and spatial accuracy in existing methods, and the fact that current fire simulation results are mostly presented as static charts or two-dimensional planes, lacking an integrated display mode with the 3D building model and failing to intuitively represent the dynamic evolution of fire spread and radiation hazard areas, this invention proposes a method and system for simulating and analyzing indoor fire thermal radiation in chemical plant buildings based on a point source radiation model. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to solve the problems of insufficient accuracy, poor real-time performance and limited visualization ability in the existing technology of thermal radiation analysis of indoor fires in chemical plant buildings. This invention provides a thermal radiation simulation analysis method for indoor fires in chemical plant buildings. By highly layered discretization of the indoor space, a layered radiation calculation model is established. Combined with the Unity3D three-dimensional visualization platform, the thermal radiation intensity distribution is superimposed on the real building model in the form of a cloud map, thereby dynamically displaying the changes in the thermal radiation hazard area during the fire spread process, providing scientific support for evacuation route optimization, firefighter safety work zone delineation and emergency rescue decision-making.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution, and the present invention includes the following steps:

[0007] S1: Model Building

[0008] Collect building data of chemical plant buildings, obtain fire design information, and create an interior geometric model of the chemical plant buildings that is consistent with the actual buildings in the modeling tool;

[0009] S2: High-level layering

[0010] Based on the building's floor height, the interior space is divided into multiple height levels along the vertical direction; a regular or irregular grid network is generated for each height level.

[0011] S3: Radiation Calculation

[0012] A mathematical expression for the thermal radiation energy density received by the surface of the target object is established, the heat release rate and radiation fraction of the fire source are set, the mathematical expression is extended to the three-dimensional world coordinate system, and then the thermal radiation flux data at any point on each height level is calculated.

[0013] S4: Hazard Classification

[0014] Statistical analysis was performed on the thermal radiation flux data at each altitude level, and hazard classification was carried out according to preset thresholds to obtain thermal radiation distribution maps and risk tables at each altitude level.

[0015] S5: Visual Display

[0016] The layered thermal radiation distribution map is mapped onto a 3D building model, and different intensities of thermal radiation distribution are displayed through color gradients. This is then presented on the Unity3D platform to provide a basis for emergency plans and on-site command.

[0017] Furthermore, in step S1, the specific processing procedure is as follows:

[0018] S11: Data Acquisition

[0019] Obtain floor plans and elevations of the chemical plant buildings; collect spatial coordinates and dimensional characteristics of indoor production equipment and platform structures to establish a type that accurately reflects the layout;

[0020] S12: Fire Settings

[0021] Based on fire hazard analysis, determine the location and number of potential ignition sources, set up fire scenarios, and define initial environmental conditions;

[0022] S13: Model Building

[0023] In the modeling software, construct the interior geometric model of the chemical plant building, retaining key structural features, including the material, thickness and spatial layout of the main load-bearing components, the installation location and external dimensions of the process equipment and piping system, and the location, size and fire resistance and heat insulation properties of the opening structures.

[0024] Furthermore, in step S11, the building's floor plan and elevation drawings include dimensions, floor height, beam and column locations, door and window distribution, and ventilation information.

[0025] Furthermore, in step S2, the specific processing procedure is as follows:

[0026] S21: Based on the building's floor height and the height of the flame characteristics, the entire interior space is divided into multiple height levels along the vertical direction;

[0027] S22: A two-dimensional sampling grid is established at each height level according to the principle of equal spacing. The grid size is set according to the calculation accuracy. By integrating the three-dimensional coordinates of the grid points in each layer, a spatial coordinate node matrix is ​​generated. Each grid represents a sampling point, which is used to record the thermal radiation flux received in the corresponding area.

[0028] S23: Assign a weight coefficient to each grid cell based on the spatial characteristics of the area where the grid is located, in order to reflect the accessibility of thermal radiation flux.

[0029] Furthermore, the specific calculation method for the flame characteristic height is as follows:

[0030] ;

[0031] in, It is the height of the flame characteristic. Where D is the heat release rate of the fire source, and D is the equivalent diameter of the fire source. For non-circular fire sources, the calculation is based on the principle of area equivalence. A represents the area of ​​the fire source.

[0032] Furthermore, in step S23, the distance between the grid and the fire source is negatively correlated with the weight coefficient of the grid.

[0033] Furthermore, in step S3, the specific processing procedure is as follows:

[0034] S31: According to the basic principle of radiative heat transfer, the thermal radiation flux density received at any distance r from the fire source is... The mathematical expression is:

[0035] ;

[0036] in, The effective radiant power of the fire source , The radiation fraction of the fire source. It is the heat release rate of the fire source. denoted as θ, where θ is the angle between the normal to the target object and the line connecting the fire source and the target object, and r is the straight-line distance in space from the fire source to the target receiving point.

[0037] Step S32: Assume the fire source is located at point If the target object is located at point P(x1,y1,z1), then the distance R is:

[0038] ;

[0039] Step S33: Extending the formula in step S31 to a three-dimensional world coordinate system, the thermal radiation flux density at any point (x, y, z) in space is:

[0040] ;

[0041] Step S34: Let the height of the indoor space be H, and divide it into i height levels. Let be the height of the i-th layer. For the i-th layer plane, then any point within the plane... The thermal radiation flux density is:

[0042] .

[0043] Furthermore, in step S4, the specific processing procedure is as follows:

[0044] S41: According to relevant standards, multiple thermal radiation intensity thresholds are set to distinguish different levels of dangerous areas and realize the classification of dangerous levels;

[0045] S42: Statistically summarize the thermal radiation flux density at each height level, and based on the hazard level threshold set in S41, which is expressed in terms of thermal radiation intensity value, extract the influence radius of each level at each height level, and obtain the heat intensity level and hazard area delineation data for each height level.

[0046] S43: Traverse the grid cells at each height level, determine the hazard level of their thermal radiation intensity, and add the corresponding hazard level label to the grid cells.

[0047] S44: Map hazard levels to colors, use gradient colors to identify different hazard level information, and generate corresponding distribution maps at each altitude level;

[0048] S45: Outputs thermal radiation flux data and hazard zone data for each floor and generates charts to guide evacuation route analysis, firefighter safety zone delineation, and emergency strategy optimization.

[0049] Furthermore, in step S41, the different levels of danger zones are as follows:

[0050] High-risk area: thermal radiation intensity >25kW / m²;

[0051] Medium-danger zone: thermal radiation intensity is 12.5 kW / m² to 25 kW / m²;

[0052] Low-risk area: thermal radiation intensity of 4kW / m²~12.5kW / m²;

[0053] Safe zone: Thermal radiation intensity <1.6kW / m².

[0054] This invention also provides a thermal radiation simulation analysis system for indoor fires in chemical plant buildings, applied to the above-mentioned method, comprising:

[0055] The model building module is used to collect building data of chemical plant buildings, obtain fire design information, and build an interior geometric model of the chemical plant buildings that is consistent with the actual buildings in the modeling tool.

[0056] The height layering module is used to divide the interior space into multiple height layers vertically according to the building's floor height; and to generate a regular or irregular grid network for each height layer.

[0057] The radiation calculation module is used to establish a mathematical expression for the thermal radiation energy density received by the surface of the target object, set the heat release rate of the fire source and the radiation fraction, extend the mathematical expression to the three-dimensional world coordinate system, and then calculate the thermal radiation flux data at any point on each height level.

[0058] The hazard classification module is used to perform statistical analysis on the thermal radiation flux data at each altitude level, and classify the hazard according to preset thresholds to obtain thermal radiation distribution maps and risk tables at each altitude level.

[0059] The visualization module is used to map layered thermal radiation distribution maps onto 3D building models, displaying thermal radiation distributions of different intensities through color gradients. It is displayed on the Unity3D platform, providing a basis for emergency plans and on-site command.

[0060] The present invention has the following advantages over the prior art:

[0061] (1) Based on the point source radiation model, this invention introduces spatial height stratification and grid discretization calculation formulas, which can refine the spatial resolution of indoor thermal radiation distribution without significantly increasing the amount of calculation, and overcome the problem that the traditional point source model does not adequately consider the spatial stratification features.

[0062] (2) The present invention uses a pixel visualization method to map the thermal radiation flux value into different colored grids, and uses color gradients to intuitively reflect the radiation intensity distribution. This enables the spatial characteristics of indoor fire thermal radiation to be presented quickly without complex CFD calculations, thus improving the real-time performance of simulation and application.

[0063] (3) By setting weight coefficients for grid cells, this invention can effectively consider the influence of building weight, equipment distribution and other factors on radiation transmission, making the calculation results closer to the real fire situation and making up for the lack of accuracy of traditional simplified models in complex spaces.

[0064] (4) The simulation results of the present invention can be dynamically superimposed with the three-dimensional building model to form a thermal radiation cloud map, making the range of fire hazard zone more visible and providing reliable technical support for the formulation of fire emergency plans, optimization of personnel evacuation routes and delineation of safe working areas for firefighters.

[0065] (5) The overall implementation process of this invention is simple, the calculation speed is fast, and the scalability is strong. It is suitable for complex scenarios such as indoor chemical plants, and has significant engineering practical value and promotion significance. Attached Figure Description

[0066] Figure 1 This is a flowchart illustrating a method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building, according to the present invention.

[0067] Figure 2 This is an overall modeling diagram of the chemical plant building in an embodiment of the present invention. Detailed Implementation

[0068] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0069] Example 1

[0070] like Figure 1 As shown, this embodiment provides a technical solution: a method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building, comprising the following steps:

[0071] S1: Model Building

[0072] Collect building data of chemical plant buildings, obtain fire design information, and create an interior geometric model of the chemical plant buildings that is consistent with the actual buildings in the modeling tool;

[0073] S2: High-level layering

[0074] Based on the building's floor height, the interior space is divided into multiple height levels along the vertical direction; a regular or irregular grid network is generated for each height level to form a "layer → grid" computational domain, providing a discrete carrier for subsequent radiative flux calculation;

[0075] S3: Radiation Calculation

[0076] A mathematical expression for the thermal radiation energy density received by the surface of the target object is established, the heat release rate and radiation fraction of the fire source are set, the mathematical expression is extended to the three-dimensional world coordinate system, and then the thermal radiation flux data at any point on each height level is calculated.

[0077] S4: Hazard Classification

[0078] Statistical analysis of thermal radiation flux data at each altitude level is performed, and hazard classification is carried out according to preset thresholds to generate a "layer → level" risk table to support the determination of evacuation and operation boundaries.

[0079] S5: Visual Display

[0080] Layered thermal radiation data is mapped onto a 3D building model, and thermal radiation cloud maps are generated using color gradients. These maps are then displayed on the Unity3D platform, providing a basis for emergency plans and on-site command.

[0081] In this embodiment, the specific processing procedure in step S1 is as follows:

[0082] S11: Data Acquisition

[0083] Obtain floor plans and elevations of the chemical plant buildings, including dimensions, floor height, beam and column locations, door and window distribution, ventilation openings, and other information; collect spatial coordinates and dimensional characteristics of indoor production equipment and platform structures to establish a type that accurately reflects the layout;

[0084] In this embodiment, spatial coordinates and dimensional features are used to construct a high-fidelity three-dimensional indoor geometric model. This model not only includes the building structure but also accurately reproduces the actual layout, occlusion relationship, and heat radiation propagation path of equipment and platforms in space. This geometric model is a necessary spatial foundation for subsequent fire scene modeling, heat radiation field calculation, personnel evacuation simulation, and safety risk assessment.

[0085] S12: Fire Settings

[0086] Based on fire hazard analysis, determine the location and number of potential ignition sources, set typical fire scenarios, and define initial environmental conditions;

[0087] Specifically, the initial environmental conditions include, but are not limited to, the following parameters: initial indoor air temperature, ambient pressure, ambient oxygen mass fraction, ambient carbon dioxide mass fraction, air density, relative humidity, ventilation status, and background wind speed.

[0088] S13: Model Building

[0089] Construct a 3D interior geometric model of the chemical plant building in modeling software (such as 3ds Max or Unity modeling platform), retaining key structural features, including the material, thickness and spatial layout of load-bearing components such as wall panels, floor slabs, beams and columns of the main building, the installation location and external dimensions of process equipment and piping systems, and the location, size and fire resistance and heat insulation properties of opening structures such as doors, windows and ventilation openings.

[0090] In this embodiment, the specific processing procedure in step S2 is as follows:

[0091] S21: Based on the building floor height and flame characteristic height, the entire indoor space is divided into multiple calculation layers along the vertical direction. The indoor building floor height is about 3 meters, which can be divided into 6 layers, each 0.5m high.

[0092] More specifically, the calculation method for flame feature height is as follows:

[0093] The calculation is performed using Heskestad's empirical formula, and its mathematical expression is as follows:

[0094] ;

[0095] in, It is the characteristic height of the flame, measured in meters (m). D is the heat release rate of the fire source, measured in kilowatts (kW), and D is the equivalent diameter of the fire source, measured in meters (m). For non-circular fire sources, the equivalent area principle can be used for calculation. A is the area of ​​the fire source (unit: ).

[0096] S22: A two-dimensional sampling grid is established at each height level according to the principle of equal spacing. The grid size can be set according to the calculation accuracy. By integrating the three-dimensional coordinates of the grid points in each layer, a spatial coordinate node matrix is ​​generated, where each grid represents a sampling point to record the thermal radiation flux received in that area.

[0097] S23: Assign a weight coefficient to each grid cell based on the spatial characteristics of the area where the grid is located (such as proximity to a fire source) to reflect the accessibility of thermal radiation flux. The weight of areas far from the fire source can be reduced proportionally to the distance.

[0098] In this embodiment, the specific processing procedure in step S3 is as follows:

[0099] S31: According to the basic principle of radiative heat transfer, the thermal radiation flux density received at any distance r from the heat source (using...) The mathematical expression for (represented by) is:

[0100] ;

[0101] in, It is the thermal radiation flux density on the receiving surface at a distance r from the fire source, in units of , The effective radiant power of the fire source, in units , , The radiation fraction of the fire source. It is the heat release rate of the fire source. The angle between the normal to the target object and the line connecting the fire source and the target object is r, which is the straight-line distance in space from the fire source to the target receiving point, in meters.

[0102] Step S32: Assume the fire source is located at If the target object is located at point P(x1,y1,z1), then the distance R is:

[0103] ;

[0104] Step S33: Extending the formula in step S31 to a three-dimensional world coordinate system, the thermal radiation flux density at any point (x, y, z) in space is:

[0105] ;

[0106] Step S34: Let the height of the indoor space be H, and divide it into i height levels. Let z be the height of the i-th layer. For the i-th layer plane (z= Then any point in the plane The thermal radiation flux density is:

[0107] .

[0108] In this embodiment, the specific processing procedure in step S4 is as follows:

[0109] S41: Based on national or industry standards, multiple radiation intensity thresholds are set to distinguish different levels of hazardous areas, thereby achieving hazard level classification.

[0110] High-risk area: Radiation intensity > 25 kW / m² (100% mortality within 1 minute, severe burns within 10 seconds);

[0111] Medium-risk zone: Radiation intensity 12.5kW / m²~25kW / m² (1% mortality rate within 1 minute, first-degree burns within 10 seconds);

[0112] Low-risk area: Radiation intensity 4kW / m²~12.5kW / m² (pain will occur after more than 20 seconds, but no blisters will form);

[0113] Safe zone: Radiation intensity <1.6kW / m² (no discomfort after prolonged exposure).

[0114] S42: Statistically summarize the thermal radiation flux data for each altitude level, and extract the influence radius of each level for each layer based on the hazard level threshold set in S41, which is expressed in terms of thermal radiation intensity value. Through these statistics, the heat intensity level of the altitude level can be determined, thereby completing the delineation of the hazard area.

[0115] As a further step, the steps for extracting the radius of influence are as follows:

[0116] 1. For each height level, calculate the thermal radiation flux at all horizontal grid points;

[0117] 2. For each hazard level threshold, select all grid points in the current altitude layer whose thermal radiation flux is greater than or equal to the hazard level threshold. The set of these grid points constitutes the hazard area of ​​that level in that altitude layer.

[0118] 3. Calculate the horizontal distance from the grid points within each hazard level selected in step 2 to the projection point of the fire source on the plane at that height, and take the maximum value. This maximum value is the influence radius corresponding to the hazard level threshold at the current height. The influence radius can be calculated using the following formula:

[0119]

[0120] 4. Output the influence radius of each hazard level at each height level. By comparing the influence radius of the same level at different height levels, determine the vertical distribution of the heat intensity level (the larger the radius, the wider the influence range, and the higher the potential risk). By drawing the influence range boundary of each level, complete the delineation of the hazard area at that height level.

[0121] S43: Traverse the grid cells at each level, determine the danger level of their thermal radiation intensity, and add the corresponding danger level label (e.g., 1=Warning, 2=Danger, 3=Lethal).

[0122] S44: Map hazard levels to colors, use gradient colors to identify different hazard level information, and generate corresponding distribution maps at each altitude level;

[0123] S45: Outputs thermal radiation flux data and hazard zone data for each floor and generates charts to guide evacuation route analysis, firefighter safety zone delineation, and emergency strategy optimization.

[0124] Example 2

[0125] This embodiment provides a technical solution: a method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building, comprising the following steps:

[0126] Taking the indoor shipping containers of a chemical plant as the research object, each container is 12m long, 3m wide and 3m high. The interior material is conventional decoration material and there are several pieces of equipment inside. The bottom middle position of a certain container is selected as the fire source point, and the flame height is about half of the indoor height.

[0127] 1. Scene Modeling: Collect information such as the structural dimensions, floor height, material parameters, and equipment layout of the indoor building to create a 3D geometric model consistent with reality. The fire situation is determined by defining parameters such as the location of the fire source, fire power, and ventilation conditions. The model can be created using 3ds Max software and imported into the simulation analysis platform.

[0128] In this embodiment, the overall modeling effect diagram is as follows: Figure 2 As shown.

[0129] 2. Height Stratification: Based on the building's floor height and spatial function, the interior space is divided vertically into six height levels, each approximately 0.5m thick. A two-dimensional rectangular grid (square) is established for each level, with each square serving as a sampling unit to store radiant flux values. Weighting coefficients are assigned to each square based on its location, with weights proportionally reduced for squares farther from fire sources. After calculation, the flux values ​​of each square are mapped to a preset color table (blue-green-yellow-red), with color intensity representing varying levels of radiation intensity.

[0130] 3. Parameter Calculation: The actual fire source is equivalent to one or more point sources, and its heat release rate and effective radiation fraction are defined. For multi-fire source scenarios, the superposition method is used to calculate the overall radiation intensity. The received radiant flux is calculated for each grid cell at each level, using the following formula: The calculation is implemented using C# programming, traversing all grid cells.

[0131] 4. Classification by Risk Level: Based on the calculation results, the maximum radiation values ​​for each layer are as follows: Layer 1 > 25 kW / m², Layer 2 12.5 kW / m², Layer 3 4 kW / m², and the remaining layers < 1.6 kW / m². Based on threshold classification: High-risk zone (>25 kW / m²), Medium-risk zone (12.5~25 kW / m²), Low-risk zone (4~12.5 kW / m²), and Safe zone (<1.6 kW / m²), a graded thermal radiation cloud map is drawn, dividing the area into three levels: lethal, dangerous, and warning.

[0132] 5. Visualization Output: The graded thermal radiation cloud maps of each level are overlaid onto the 3D building model, using color gradients to display the distribution of thermal radiation at different intensities. Displayed through the Unity3D platform, it visually shows the fire spread and the intensity distribution of the thermal radiation area, ultimately exporting the thermal radiation cloud map and hazard classification statistics table for each level.

[0133] In this embodiment, the method can accurately reflect the variation of fire heat radiation at different heights and in different areas, and can also effectively take into account the influence of complex factors such as building structure. Furthermore, this method is universally applicable and can be widely used in indoor fire safety analysis scenarios such as chemical plants, warehouses, and power facilities, providing a scientific basis for fire hazard assessment, emergency evacuation design, and fire prevention plans, and has high engineering application value.

[0134] In summary, the thermal radiation simulation analysis method for indoor fires in chemical plant buildings described in the above embodiments achieves rapid calculation and intuitive display of fire thermal radiation distribution through steps such as 3D scene modeling, highly layered discretization, model radiation calculation, and hazard classification. This method does not rely on complex fluid dynamics solutions and obtains high-precision thermal radiation distribution results through point source radiation calculation and pixel visualization, significantly improving computational efficiency and practicality.

[0135] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for simulating and analyzing thermal radiation in indoor fires in chemical plant buildings, characterized in that, Includes the following steps: S1: Model Building Collect building data of chemical plant buildings, obtain fire design information, and create an interior geometric model of the chemical plant buildings that is consistent with the actual buildings in the modeling tool; S2: High-level layering Based on the building's floor height, the interior space is divided into multiple height levels along the vertical direction; a regular or irregular grid network is generated for each height level. S3: Radiation Calculation A mathematical expression for the thermal radiation energy density received by the surface of the target object is established, the heat release rate and radiation fraction of the fire source are set, the mathematical expression is extended to the three-dimensional world coordinate system, and then the thermal radiation flux data at any point on each height level is calculated. S4: Hazard Classification Statistical analysis was performed on the thermal radiation flux data at each altitude level, and hazard classification was carried out according to preset thresholds to obtain thermal radiation distribution maps and risk tables at each altitude level. S5: Visual Display The layered thermal radiation distribution map is mapped onto a 3D building model, and different intensities of thermal radiation distribution are displayed through color gradients. This is then presented on the Unity3D platform to provide a basis for emergency plans and on-site command.

2. The method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building according to claim 1, characterized in that, In step S1, the specific processing procedure is as follows: S11: Data Acquisition Obtain floor plans and elevations of the chemical plant buildings; collect spatial coordinates and dimensional characteristics of indoor production equipment and platform structures to establish a type that accurately reflects the layout; S12: Fire Settings Based on fire hazard analysis, determine the location and number of potential ignition sources, set up fire scenarios, and define initial environmental conditions; S13: Model Building In the modeling software, construct the interior geometric model of the chemical plant building, retaining key structural features, including the material, thickness and spatial layout of the main load-bearing components, the installation location and external dimensions of the process equipment and piping system, and the location, size and fire resistance and heat insulation properties of the opening structures.

3. The method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building according to claim 2, characterized in that, In step S11, the building's floor plan and elevation plan include dimensions, floor height, beam and column locations, door and window distribution, and ventilation information.

4. The method for thermal radiation simulation analysis of indoor fires in chemical plant buildings according to claim 2, characterized in that, In step S2, the specific processing procedure is as follows: S21: Based on the building's floor height and the height of the flame characteristics, the entire interior space is divided into multiple height levels along the vertical direction; S22: A two-dimensional sampling grid is established at each height level according to the principle of equal spacing. The grid size is set according to the calculation accuracy. By integrating the three-dimensional coordinates of the grid points in each layer, a spatial coordinate node matrix is ​​generated. Each grid represents a sampling point, which is used to record the thermal radiation flux received in the corresponding area. S23: Assign a weight coefficient to each grid cell based on the spatial characteristics of the area where the grid is located, in order to reflect the accessibility of thermal radiation flux.

5. The method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building according to claim 4, characterized in that, The specific calculation method for flame characteristic height is as follows: ； in, It is the height of the flame characteristic. Where D is the heat release rate of the fire source, and D is the equivalent diameter of the fire source. For non-circular fire sources, the calculation is based on the principle of area equivalence. A represents the area of ​​the fire source.

6. The method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building according to claim 4, characterized in that, In step S23, the distance between the grid and the fire source is negatively correlated with the weight coefficient of the grid.

7. The method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building according to claim 4, characterized in that, In step S3, the specific processing procedure is as follows: S31: According to the basic principle of radiative heat transfer, the thermal radiation flux density received at any distance r from the fire source is... The mathematical expression is: ； in, The effective radiant power of the fire source , The radiation fraction of the fire source. It is the heat release rate of the fire source. denoted as θ, where θ is the angle between the normal to the target object and the line connecting the fire source and the target object, and r is the straight-line distance in space from the fire source to the target receiving point. Step S32: Assume the fire source is located at point If the target object is located at point P(x1,y1,z1), then the distance R is: ； Step S33: Extending the formula in step S31 to a three-dimensional world coordinate system, the thermal radiation flux density at any point (x, y, z) in space is: ； Step S34: Let the height of the indoor space be H, and divide it into i height levels. Let be the height of the i-th layer. For the i-th layer plane, then any point within the plane... The thermal radiation flux density is: 。 8. The method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building according to claim 7, characterized in that, In step S4, the specific processing procedure is as follows: S41: According to relevant standards, multiple thermal radiation intensity thresholds are set to distinguish different levels of dangerous areas and realize the classification of dangerous levels; S42: Statistically summarize the thermal radiation flux density at each height level, and based on the hazard level threshold set in S41, which is expressed in terms of thermal radiation intensity value, extract the influence radius of each level at each height level, and obtain the heat intensity level and hazard area delineation data for each height level. S43: Traverse the grid cells at each height level, determine the hazard level of their thermal radiation intensity, and add the corresponding hazard level label to the grid cells. S44: Map hazard levels to colors, use gradient colors to identify different hazard level information, and generate corresponding distribution maps at each altitude level; S45: Outputs thermal radiation flux data and hazard zone data for each floor and generates charts to guide evacuation route analysis, firefighter safety zone delineation, and emergency strategy optimization.

9. The method for simulating and analyzing the thermal radiation of an indoor fire in a chemical plant building according to claim 8, characterized in that, In step S41, the different levels of danger zones are as follows: High-risk area: thermal radiation intensity >25kW / m²; Medium-danger zone: thermal radiation intensity is 12.5 kW / m² to 25 kW / m²; Low-risk area: thermal radiation intensity of 4kW / m²~12.5kW / m²; Safe zone: Thermal radiation intensity <1.6kW / m².

10. A thermal radiation simulation analysis system for indoor fires in chemical plant buildings, characterized in that, The method applied to any one of claims 1 to 9 includes: The model building module is used to collect building data of chemical plant buildings, obtain fire design information, and build an interior geometric model of the chemical plant buildings that is consistent with the actual buildings in the modeling tool. The height layering module is used to divide the interior space into multiple height layers vertically according to the building's floor height; and to generate a regular or irregular grid network for each height layer. The radiation calculation module is used to establish a mathematical expression for the thermal radiation energy density received by the surface of the target object, set the heat release rate of the fire source and the radiation fraction, extend the mathematical expression to the three-dimensional world coordinate system, and then calculate the thermal radiation flux data at any point on each height level. The hazard classification module is used to perform statistical analysis on the thermal radiation flux data at each altitude level, and classify the hazard according to preset thresholds to obtain thermal radiation distribution maps and risk tables at each altitude level. The visualization module is used to map layered thermal radiation distribution maps onto 3D building models, displaying thermal radiation distributions of different intensities through color gradients. It is displayed on the Unity3D platform, providing a basis for emergency plans and on-site command.

Images