Simulation Evaluation Method for Sudden Flame Behavior Induced by Rigid Porous Materials in Gas Explosions

Abstract

This invention relates to a simulation evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions, belonging to the field of underground gas explosion protection technology in coal mines. The method includes the following steps: First, a two-dimensional slice image of the rigid porous material is obtained through X-ray CT scanning, and a high-precision three-dimensional digital model is reconstructed. Then, an FGM combustion model is constructed using the Chem1D tool combined with detailed chemical reaction mechanisms. During the simulation, key characteristics such as flame velocity, explosion overpressure, and flame temperature are acquired, and the flame propagation mode and abrupt change behavior are analyzed to evaluate the barrier performance of the porous material. This invention has significant advantages such as safety, efficiency, low cost, and no need for expensive experimental equipment. Through numerical simulation, the protective effect of different materials in gas explosions can be accurately evaluated, filling the gap in evaluating abrupt changes in flame behavior through numerical simulation, and providing reliable theoretical support and technical basis for mine safety prevention and control.

Description

Technical Field

[0001] This invention belongs to the field of underground gas explosion protection technology in coal mines, and relates to a simulation evaluation method for the sudden change in flame behavior induced by rigid porous materials in gas explosions. Background Technology

[0002] With the development of the coal industry, coal mine safety accidents have also occurred frequently, posing a serious threat to personal safety, property, and health. Among various safety accidents, gas explosions are particularly prominent, with high severity and a consistently high proportion of accidents and fatalities. The instantaneous temperature generated by a gas explosion can reach 1850°C to 2650°C, and the pressure can reach nine times the initial pressure. Gas near the explosion source is ejected at speeds of hundreds of meters per second, causing casualties, tunnel damage, and damage to equipment and facilities. In addition, the explosion also releases large amounts of toxic and harmful gases, such as carbon monoxide (CO), nitrogen oxides (NO), and carbon dioxide (CO2), posing a significant threat to personal safety and health.

[0003] The device provided by the invention patent with publication number CN115653668A relies on the adsorption properties of inert powder materials. However, the effectiveness of inert powder may not be consistent under different coal mine conditions and gas concentrations, posing a risk of limited applicability. The experimental system proposed by the invention patent with publication number CN107605527B relies on a fixed cavity structure and premixing acceleration section, and has strict regulations on parameters such as pipe length and diameter. This design is difficult to adapt to different geological conditions and gas concentration variations in actual mines. The invention patent with publication number CN109060882A proposes the concept of suppressing gas explosions through inert gas mixing and introduces a complex sensor and intelligent gas distribution system. However, this system has low accuracy in optimizing the dynamic response time of the gas and the gas mixing ratio. The utility model patent with publication number CN202693574U proposes a porous material gas explosion suppression simulation device, but it cannot provide in-depth analysis on how porous materials dynamically adjust their energy absorption, reflection, and scattering properties. The porous foam iron-nickel metal explosion-suppressing material proposed in invention patent CN102796911B lacks targeted mechanical testing to evaluate its actual performance. The one-dimensional porous media numerical simulation method proposed in invention patent CN111879818A can only simulate one-dimensional cases and is only applicable to porous media with simple shapes. It cannot simulate and evaluate three-dimensional porous media with complex pore structures.

[0004] Evaluating the explosion-proof performance and flame mutation behavior of porous materials through experimental testing has certain limitations. First, conducting experiments on real-scale underground gas explosions inevitably increases evaluation costs, and explosion experiments are inherently dangerous. Second, factors affecting the explosion-proof performance and flame mutation behavior of porous materials, such as the explosion flow field and flame temperature, are difficult to observe experimentally. In recent years, with the continuous improvement of computer performance, numerical simulation has become a more efficient, accurate, and cost-effective method for evaluating the flame mutation behavior and explosion-proof performance of porous materials. However, existing numerical simulation methods can only be applied to porous media with simple shapes and cannot accurately evaluate the explosion-proof performance and flame mutation behavior of real three-dimensional porous media. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a simulation evaluation method for the abrupt change in the flame behavior of a gas explosion induced by rigid porous materials.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A simulation evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions includes the following steps:

[0008] S1: Constructing a physical model of rigid porous materials: X-ray CT scans are performed on rigid porous materials to obtain two-dimensional slice images of the rigid porous materials. After image filtering and image segmentation, three-dimensional digital reconstruction technology is used to construct a three-dimensional digital model of the rigid porous materials.

[0009] S2: Constructing the computational grid and fluid domain for rigid porous materials: Based on the actual location of the porous material used for explosion containment, the three-dimensional digital model of the rigid porous material is embedded into the underground roadway model. Then, the computational grid of the porous material region and the gas enrichment region is drawn, and the boundary conditions of the region are named.

[0010] S3: Construct a numerical model for blocking explosions using rigid porous materials, including: constructing an FGM combustion model to solve the explosion reaction process; constructing a turbulence model to capture the turbulence characteristics of the gas explosion flame before and after passing through the rigid porous material; and constructing a flame thickening model to describe and simulate the flame thickness and its impact on the combustion process.

[0011] S4: Evaluation of numerical simulation solutions and flame propagation behavior: Solve the flame, flow field, and overpressure characteristics in a gas explosion using physical and mathematical models; record flame propagation speed, analyze flame behavior, and focus on the conditions for flame quenching and acceleration; monitor internal system pressure changes and evaluate pressure trends in different explosion scenarios; use data analysis to extract flame velocity, overpressure, and temperature characteristics, analyze flame stability, propagation modes, and abrupt change behavior, identify the influence of rigid porous materials on the gas explosion flame, and evaluate their barrier performance;

[0012] S5: Replace the porous material to be evaluated and repeat steps S1-S4. Select appropriate gas components and set the concentrations of oxygen and nitrogen components according to the enrichment level of gas to obtain the inhibitory effect of different types of rigid porous materials on gas explosions of various degrees and the influence of flame mutation behavior.

[0013] Furthermore, in step S1, the image is filtered using a median filtering method, which removes random noise by replacing the value of each pixel with the median of its neighboring pixels.

[0014] Furthermore, in step S1, the watershed algorithm is used for image segmentation. Based on the image gradient information, a threshold is set to distinguish the pore structure of the rigid porous material from the solid matrix and extract the microstructural features of the rigid porous material.

[0015] Furthermore, the three-dimensional digital reconstruction technology described in step S1 integrates the processed slice data using three-dimensional reconstruction software and generates a three-dimensional digital model using the Marching Cubes algorithm.

[0016] Furthermore, in step S2, a computational grid for the porous material region and the gas-rich region is drawn using a mesh drawing tool. The principle is to gradually refine and adapt the input geometry based on a pre-generated coarse grid.

[0017] Furthermore, step S3 specifically includes the following steps:

[0018] S31: Constructing an FGM combustion model: Combining the detailed chemical reaction mechanism of GRI-Mech3.0 and Chem1D to generate a one-dimensional PDF data table containing laminar combustion rate and component concentration; interpolating the one-dimensional PDF lookup table into a 4D FGM lookup table; importing the PDF lookup table into the simulation software, setting the type and component concentration of combustible gas according to different explosion states, and setting the component concentrations of oxygen and nitrogen according to the degree of oxygen enrichment during the explosion;

[0019] S32: A pressure-based transient solver is used to solve the explosion reaction process, and the energy equation, momentum equation and mass equation are solved. The SIMPLE pressure-velocity coupling algorithm is used to solve the simulation process, and a second-order upwind scheme is used to spatially discretize the energy, momentum, process variables and average mixing fraction.

[0020] S33: LES is used as the turbulence model in numerical calculation, and Smagorinsky-Lilly is used as the subgrid scale model to capture the turbulence characteristics of the gas explosion flame before and after passing through a rigid porous material.

[0021] S34: The flame thickness model is used to treat the flame as a reaction zone with a certain thickness, in order to describe and simulate the thickness of the flame and its effect on the combustion process.

[0022] Furthermore, the GRI-Mech3.0 chemical reaction mechanism described in step S31 includes reactants and products, and is used to simulate the combustion characteristics of various fuels; the Chem1D is used for one-dimensional combustion simulation, and by decoupling time and space variables, it uses numerical methods to simulate one-dimensional flame structure and combustion process, and analyzes the distribution of temperature, concentration and reaction rate.

[0023] Furthermore, in step S34, the flame thickness, adiabatic flame temperature, and laminar flame velocity of the gas or air mixture are first calculated to construct the flame thickening model.

[0024] Furthermore, the evaluation of the gas explosion suppression effect and flame mutation behavior of the porous material described in step S4 is reflected in the macroscopic characteristics of the flame; when the flame propagation speed decreases and is quenched after passing through the porous medium region, it indicates that the porous material has a good suppression effect on the gas explosion; when the flame can pass through the porous medium region and is accompanied by flame acceleration, it indicates that the porous material fails to suppress the gas explosion flame and cannot play a good suppression role.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. Compared to experimental testing methods, the simulation evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions proposed in this invention is safer and more efficient for evaluating the explosion-proof performance and flame abrupt change behavior of rigid porous media. Furthermore, this evaluation method does not require the construction of expensive experimental platforms, resulting in lower investment costs and simpler operation, greatly simplifying the evaluation process for the explosion-proof performance of rigid porous materials.

[0027] 2. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions proposed in this invention has high practical value. By obtaining a three-dimensional porous medium model through X-ray CT scanning of the rigid porous medium to be evaluated, and then through a series of numerical calculation methods such as computational mesh construction and combustion model construction, the flame abrupt change behavior of this type of rigid porous medium for different types and scenarios of gas explosions can be obtained, and its explosion-proof performance can be evaluated.

[0028] 3. This invention is mainly applied in the field of mine safety prevention and control. It can accurately, efficiently, and economically evaluate the explosion-proof performance and induced flame behavior mutations of different types of rigid porous materials. The simulation results are highly reliable and have strong practicality. This invention solves the technical problems of uncontrollable explosion risk and high evaluation cost in the current evaluation process of rigid porous materials, and fills the gap in evaluating the induced flame behavior mutations and explosion-proof performance of rigid porous materials through numerical simulation.

[0029] In summary, this invention has the advantages of simple operation and high prediction accuracy. By establishing a three-dimensional realistic geometric model of porous media, it is possible to accurately and efficiently evaluate the abrupt changes in flame behavior induced by different types of rigid porous media and their explosion-proof performance.

[0030] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0032] Figure 1 This is a flowchart of the simulation evaluation method for the sudden change in flame behavior induced by rigid porous materials in gas explosions, as described in the embodiments of the present invention.

[0033] Figure 2 This is a two-dimensional original slice image of a rigid porous medium obtained by X-ray CT scanning in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the geometric model of the porous medium after three-dimensional reconstruction in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the computational mesh for rigid porous materials in an embodiment of the present invention;

[0036] Figure 5This is a three-dimensional flame temperature rendering cloud map obtained from the simulation of this invention;

[0037] Figure 6 This is a two-dimensional flame temperature slice cloud map obtained from the simulation of this invention;

[0038] Figure 7 This is the explosion overpressure curve obtained from the simulation of this invention;

[0039] Figure 8 This is a simulation curve of the flame propagation position obtained by the present invention;

[0040] Figure 9 This is a curve of flame propagation speed obtained from the simulation of this invention. Detailed Implementation

[0041] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0042] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the figures only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0043] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0044] like Figure 1 As shown, this invention provides a simulation evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions, comprising the following steps:

[0045] Step 1: Construction of the physical model of the rigid porous material: X-ray CT scans are performed on the actual geometric model of the rigid porous material to be evaluated to obtain two-dimensional slice images of the rigid porous material. Then, image filtering and image segmentation techniques are combined with three-dimensional digital reconstruction techniques to obtain a high-precision three-dimensional digital model of the actual rigid porous material.

[0046] like Figure 2 As shown, a high-energy X-ray CT scanner was selected for X-ray CT scanning to ensure high-quality scanning at micron-level resolution. The equipment was calibrated before use, including adjustments to the voltage and current of the X-ray source and the detector sensitivity, to ensure data accuracy. The slice thickness was controlled at 0.1 mm to ensure high-resolution data acquisition. A 360-degree omnidirectional scan was performed to acquire multiple sets of two-dimensional slice data of the sample, ensuring coverage of all areas of the material. After each scan, the data was stored in DICOM format for subsequent processing and analysis.

[0047] In this step, the image filtering technique specifically employs median filtering. This method effectively removes random noise, particularly salt-and-pepper noise, by replacing each pixel value with the median value of its neighboring pixels. This approach preserves the image's edge features, thus providing an accurate model for subsequent processing stages.

[0048] In this step, the image segmentation technique specifically employs the watershed algorithm. This method, based on image gradient information, segments different regions within the image. By setting an appropriate threshold, the pore structure of rigid porous materials can be clearly distinguished from the solid matrix, extracting the microstructural features of the rigid porous material. It effectively captures fine features, providing accurate shape information for subsequent 3D digital reconstruction.

[0049] like Figure 3 As shown, the three-dimensional digital reconstruction technology uses the three-dimensional reconstruction software Avizo to integrate the processed slice data and uses the Marching Cubes algorithm to generate a high-precision three-dimensional digital model, ensuring the accurate representation of porosity and structural features.

[0050] Step Two: Construction of the Computational Mesh and Fluid Domain for Rigid Porous Materials: The underground roadway is simplified to a cuboid structure according to a certain scale. Based on the actual location of the porous material used for explosion containment, the high-precision 3D digital model of the porous material described in Step One is embedded into the underground roadway. The computational mesh for the porous material region and the gas-enriched region is drawn using the open-source meshing tool SnappyHexMesh, and the boundary conditions of these regions are named to construct the computational mesh and fluid domain for the rigid porous material. (Appendix) Figure 4 This is a schematic diagram of the computational mesh for rigid porous materials drawn using the SnappyHexMesh tool in an embodiment of the present invention, which ultimately yielded... Figure 5 The geometric model of the rigid porous material and the computational fluid domain in the embodiment of the present invention is shown.

[0051] The SnappyHexMesh meshing tool works by progressively refining and adapting a pre-generated coarse mesh to fit the input geometry. It combines the advantages of hexahedral meshes with mesh refinement techniques, enabling the generation of smooth and consistent meshes on complex boundaries. This tool allows for the accurate and efficient construction of high-quality computational meshes that incorporate rigid porous materials.

[0052] Step 3: Construction of the numerical model for explosion-proof rigid porous materials. The specific process is as follows:

[0053] Step 301: FGM Combustion Model Construction: A one-dimensional PDF data table containing parameters such as laminar combustion rate and component concentration is generated by combining the detailed chemical reaction mechanism of GRI-Mech3.0 and Chem1D. Python code is used to interpolate the one-dimensional PDF lookup table into a 4D FGM lookup table. The PDF lookup table is imported into the simulation software, and the types and concentrations of combustible gases are set according to different explosion states. The concentrations of oxygen and nitrogen are set according to the degree of oxygen enrichment during the explosion.

[0054] GRI-Mech3.0 chemical reaction mechanism is a detailed chemical mechanism for combustion and chemical reaction kinetics, widely used in flame modeling. It includes a large number of reactants and products, and can effectively simulate the combustion characteristics of various fuels. Chem1D is mainly used for one-dimensional combustion simulation. By decoupling time and space variables, it uses suitable numerical methods to simulate one-dimensional flame structure and combustion processes, and analyze the distribution of temperature, concentration, and reaction rate.

[0055] Step 302, Solution Algorithm: The pressure-based transient solver is used to solve the explosion reaction process. The solution mainly focuses on the energy equation, momentum equation, and mass equation. The SIMPLE pressure-velocity coupled algorithm is used to solve the simulation process, and a second-order upwind scheme is used to spatially discretize the energy, momentum, process variables, and average mixing fraction.

[0056] Step 303, Turbulence Model Selection: In order to more effectively capture the turbulence characteristics of the gas explosion flame before and after passing through the rigid porous material, and to accurately evaluate the sudden change behavior of the flame, LES is adopted as the turbulence model in the numerical calculation, and Smagorinsky-Lilly is used as the subgrid scale model.

[0057] Step 304: Flame Thickening Model Construction: The flame thickening model is written into a user-defined function using C++ to achieve accurate analysis of the flame surface structure at a relatively coarse mesh scale. Before building the flame thickening model, it is necessary to determine the flame thickness, adiabatic flame temperature, and laminar flame velocity of the gas / air mixture to be calculated. The calculation tool used is the open-source chemical reaction kinetics software Cantera. The core idea of ​​the flame thickening model is to treat the flame as a reaction zone with a certain thickness, mainly used to describe and simulate the flame thickness and its impact on the combustion process.

[0058] Step 4: Numerical Simulation and Flame Propagation Behavior Assessment: After completing the relevant preprocessing steps, the constructed geometric and numerical models are solved to obtain the gas explosion flame, flow field, and overpressure characteristics under the action of rigid porous materials. During the simulation, the flame propagation velocity is recorded, and the flame behavior under different conditions is analyzed. Special attention is paid to the timing and conditions of flame quenching and flame acceleration. Pressure changes within the system are monitored, and the pressure variation trend under different explosion scenarios is analyzed. (Appendix) Figure 5 and attached Figure 6 These are, respectively, the three-dimensional flame temperature rendering cloud map and the two-dimensional flame temperature slice cloud map obtained from the simulation of this invention; the two sets of working conditions in the figures correspond to two different thicknesses of porous materials. The flame temperature evaluation results show that the thinner rigid porous material accelerates the flame, and the explosion-blocking effect of the porous material fails. Conversely, the thicker rigid porous material quenches the flame, and the explosion-blocking effect of the porous medium is successful. Therefore, the simulation evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions proposed in this invention can accurately assess the acceleration and quenching behavior of the flame.

[0059] Data analysis tools were used to extract key features such as flame location, explosion overpressure, and flame velocity from the simulated data to analyze the flame stability, propagation mode, and abrupt change behavior. This allowed for the determination of the abrupt change law of the flame behavior induced by rigid porous materials in gas explosions and the evaluation of the explosion-proof performance of rigid porous materials. (Appendix) Figure 7 Appendix Figure 8 and attached Figure 9This data, obtained through data analysis tools, includes explosion overpressure, flame propagation location, and flame propagation velocity data under different flame abrupt changes. Besides using the aforementioned 3D flame rendering cloud maps and 2D temperature cloud maps to determine flame behavioral abrupt changes, quantitative data on explosion overpressure, flame propagation location, and flame propagation velocity can also be used to determine the flame behavioral abrupt change pattern and further evaluate the explosion-blocking performance of rigid porous media. The evaluation of the gas explosion suppression effect of porous materials and flame abrupt change behavior is mainly reflected in the macroscopic characteristics of the flame. When the flame propagation velocity decreases and quenching occurs after passing through the porous media region, it indicates that the porous material has a good suppression effect on the gas explosion. When the flame can pass through the porous media region and is accompanied by flame acceleration, the suppression effect of the porous material on the gas explosion flame becomes ineffective, and it cannot play a good suppression role.

[0060] Step 5: Replace the porous material to be evaluated and repeat steps 1 to 4, selecting appropriate gas components and setting the concentrations of oxygen and nitrogen according to the gas enrichment level. This allows us to obtain the suppression effect of different types of rigid porous materials on gas explosions of various degrees and the influence of flame mutation behavior.

[0061] In the above embodiments, the reference to "this embodiment" in the specification indicates that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least some embodiments, but not necessarily all embodiments. Multiple appearances of "this embodiment" do not necessarily all refer to the same embodiment.

[0062] In the above embodiments, although the invention has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory structures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed. The embodiments of the invention are intended to cover all such substitutions, modifications, and variations falling within the broad scope of the appended claims.

[0063] This embodiment also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the methods in this embodiment.

[0064] This embodiment also provides an electronic terminal, including: a processor and a memory;

[0065] The memory is used to store computer programs, and the processor is used to execute the computer programs stored in the memory to cause the terminal to perform any of the methods in this embodiment.

[0066] As will be understood by those skilled in the art, the computer-readable storage medium described in this embodiment allows for the implementation of all or part of the steps in the above method embodiments by computer program-related hardware. The aforementioned computer program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0067] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver, and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication between them. The memory is used to store computer programs, the communication interface is used to perform communication, and the processor and the transceiver are used to run the computer programs, so that the electronic terminal performs the steps of the above method.

[0068] In this embodiment, the memory may include random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device.

[0069] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0070] This invention can be used in a wide range of general-purpose or special-purpose computing system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices, etc.

[0071] This invention can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This invention can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions, characterized in that: Includes the following steps: S1: Constructing a physical model of rigid porous materials: X-ray CT scans are performed on rigid porous materials to obtain two-dimensional slice images of the rigid porous materials. After image filtering and image segmentation, three-dimensional digital reconstruction technology is used to construct a three-dimensional digital model of the rigid porous materials. S2: Constructing the computational grid and fluid domain for rigid porous materials: Based on the actual location of the porous material used for explosion containment, the three-dimensional digital model of the rigid porous material is embedded into the underground roadway model. Then, the computational grid of the porous material region and the gas enrichment region is drawn, and the boundary conditions of the region are named. S3: Construct a numerical model for blocking explosions using rigid porous materials, including: constructing an FGM combustion model to solve the explosion reaction process; constructing a turbulence model to capture the turbulence characteristics of the gas explosion flame before and after passing through the rigid porous material; and constructing a flame thickening model to describe and simulate the flame thickness and its impact on the combustion process. S4: Evaluation of numerical simulation solutions and flame propagation behavior: Solve the flame, flow field, and overpressure characteristics in a gas explosion using physical and mathematical models; record flame propagation speed, analyze flame behavior, and focus on the conditions for flame quenching and acceleration; monitor internal system pressure changes and evaluate pressure trends in different explosion scenarios; use data analysis to extract flame velocity, overpressure, and temperature characteristics, analyze flame stability, propagation modes, and abrupt change behavior, identify the influence of rigid porous materials on the gas explosion flame, and evaluate their barrier performance; S5: Replace the porous material to be evaluated and repeat steps S1-S4. Select appropriate gas components and set the concentrations of oxygen and nitrogen components according to the enrichment level of gas to obtain the inhibitory effect of different types of rigid porous materials on gas explosions of various degrees and the influence of flame mutation behavior.

2. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 1, characterized in that: In step S1, the image is filtered using the median filtering method, which removes random noise by replacing the value of each pixel with the median value of its neighboring pixels.

3. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 1, characterized in that: In step S1, the watershed algorithm is used for image segmentation. Based on the image gradient information, a threshold is set to distinguish the pore structure of rigid porous materials from the solid matrix and extract the microstructural features of rigid porous materials.

4. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 1, characterized in that: The three-dimensional digital reconstruction technology described in step S1 involves integrating the processed slice data using three-dimensional reconstruction software and generating a three-dimensional digital model using the Marching Cubes algorithm.

5. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 1, characterized in that: In step S2, the computational grid of the porous material region and the gas enrichment region is drawn using a mesh drawing tool. The principle is to gradually refine and adapt to the input geometry based on a pre-generated coarse grid.

6. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 1, characterized in that: Step S3 specifically includes the following steps: S31: Constructing an FGM combustion model: Combining the detailed chemical reaction mechanism of GRI-Mech3.0 and Chem1D to generate a one-dimensional PDF data table containing laminar combustion rate and component concentration; interpolating the one-dimensional PDF lookup table into a 4D FGM lookup table; importing the PDF lookup table into the simulation software, setting the type and component concentration of combustible gas according to different explosion states, and setting the component concentrations of oxygen and nitrogen according to the degree of oxygen enrichment during the explosion; S32: A pressure-based transient solver is used to solve the explosion reaction process, and the energy equation, momentum equation and mass equation are solved. The SIMPLE pressure-velocity coupling algorithm is used to solve the simulation process, and a second-order upwind scheme is used to spatially discretize the energy, momentum, process variables and average mixing fraction. S33: LES is used as the turbulence model in numerical calculation, and Smagorinsky-Lilly is used as the subgrid scale model to capture the turbulence characteristics of the gas explosion flame before and after passing through a rigid porous material. S34: The flame thickness model is used to treat the flame as a reaction zone with a certain thickness, in order to describe and simulate the thickness of the flame and its effect on the combustion process.

7. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 6, characterized in that: The GRI-Mech3.0 chemical reaction mechanism described in step S31 includes reactants and products and is used to simulate the combustion characteristics of various fuels; Chem1D is used for one-dimensional combustion simulation, which uses numerical methods to simulate one-dimensional flame structure and combustion process by decoupling time and space variables, and analyzes the distribution of temperature, concentration and reaction rate.

8. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 6, characterized in that: In step S34, the flame thickness, adiabatic flame temperature, and laminar flame velocity of the gas or air mixture are first calculated to construct the flame thickening model.

9. The simulation and evaluation method for the abrupt change in flame behavior induced by rigid porous materials in gas explosions according to claim 1, characterized in that: The evaluation of the gas explosion suppression effect and flame mutation behavior of the porous material described in step S4 is reflected in the macroscopic characteristics of the flame. When the flame propagation speed decreases and is quenched after passing through the porous medium region, it indicates that the porous material has a good suppression effect on the gas explosion. When the flame can pass through the porous medium region and is accompanied by flame acceleration, it indicates that the porous material fails to suppress the gas explosion flame and cannot play a good suppression role.

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