Simulation evaluation method for inducing gas explosion flame behavior mutation by rigid porous material

Abstract

The invention relates to a simulation evaluation method for inducing gas explosion flame behavior mutation by a rigid porous material, and belongs to the technical field of coal mine underground gas explosion protection, and the method comprises the following steps: firstly, obtaining a two-dimensional slice map of the rigid porous material through X-ray CT scanning, and reconstructing a high-precision three-dimensional digital model; constructing an FGM combustion model by using a Chem1D tool in combination with a detailed chemical reaction mechanism; in the simulation process, key characteristics such as flame speed, explosion overpressure and flame temperature are obtained, and flame propagation modes and mutation behaviors are analyzed so as to evaluate the barrier property of the porous material. The method has the remarkable advantages of safety, high efficiency, low cost, no need of building expensive experimental equipment and the like. Through numerical simulation, the protection effects of different materials in gas explosion can be accurately evaluated, the blank of evaluating flame behavior mutation through a numerical simulation means is filled, and reliable theoretical support and technical basis are provided for mine safety prevention and control.

Description

Technical Field

[0001] The invention belongs to the technical field of gas explosion protection in coal mines, and relates to a simulation evaluation method for rigid porous materials inducing sudden changes in gas explosion flame behavior. Background Art

[0002] With the development of the coal industry, coal mine 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 high proportion of accidents and deaths. The instantaneous temperature generated by a gas explosion can be as high as 1850℃ to 2650℃, and the pressure can reach nine times the initial pressure. The gas near the explosion source is ejected at a speed of hundreds of meters per second, resulting in casualties, tunnel damage, and damage to equipment and facilities. In addition, the explosion will also release a large amount of toxic and harmful gases, such as carbon monoxide (CO), nitrogen oxides (NO) and carbon dioxide (CO2), posing a major threat to personal safety and health.

[0003] The device provided by the invention patent with publication number CN115653668A relies on the adsorption characteristics of inert powder materials. However, under different coal mine conditions and gas concentrations, the effect of inert powder may not be generalized, and there is a risk of limited applicability. The test system proposed by the invention patent with publication number CN107605527B relies on a fixed cavity structure and a premixed acceleration section, and has strict regulations on parameters such as the length and diameter of the pipeline. This design is difficult to adapt to different geological conditions and changes in gas concentration in actual mines. The invention patent with publication number CN109060882A proposes the concept of suppressing gas explosions by inert gas blending, and introduces complex sensors and intelligent gas distribution systems, but the system has low dynamic response time for gas and low optimization accuracy for gas mixing ratio. The porous material gas explosion suppression simulation device proposed by the utility model patent with publication number CN202693574U cannot conduct relevant in-depth analysis on how porous materials dynamically adjust their energy absorption, reflection and scattering properties. The porous iron-nickel metal explosion suppression material proposed in the invention patent with publication number CN102796911B lacks targeted mechanical tests to evaluate its actual performance. The one-dimensional porous medium numerical simulation method proposed in the invention patent with publication number CN111879818A can only simulate one-dimensional situations and can only be applied to porous media with simple shapes, and cannot simulate and evaluate three-dimensional porous media with complex pore structures.

[0004] There are certain limitations in evaluating the explosion-proof performance and flame mutation behavior of porous materials through experimental testing. First, conducting experiments on real-scale underground tunnel gas explosions will inevitably increase the evaluation cost, and explosion experiments are very dangerous. Secondly, the explosion flow field and flame temperature that affect the explosion-proof performance and flame mutation behavior of porous materials are also difficult to observe through experimental means. In recent years, with the continuous improvement of computer performance, it is more efficient, accurate and cost-effective to evaluate the flame mutation behavior and explosion-proof performance of porous materials through numerical simulation. However, the existing numerical simulation methods can only be used for porous media with simple shapes, and cannot accurately evaluate the explosion-proof performance and flame mutation behavior under the action of real three-dimensional porous media. Summary of the invention

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

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A simulation evaluation method for a rigid porous material-induced gas explosion flame behavior mutation includes the following steps:

[0008] S1: Constructing a physical model of rigid porous materials: X-ray CT scanning of rigid porous materials is performed to obtain a two-dimensional slice image of the rigid porous materials. After image filtering and image segmentation, a 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 of rigid porous materials: According to the actual position of the porous material for explosion isolation, the three-dimensional digital model of the rigid porous material is embedded into the underground tunnel model, and then the computational grids of the porous material area and the gas-rich area are drawn, and the boundary conditions of the area are named;

[0010] S3: Construct a numerical model for explosion isolation of rigid porous materials, including: constructing a 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 thickness of the flame and its influence on the combustion process;

[0011] S4: Evaluate numerical simulation solutions and flame propagation behavior: Solve the flame, flow field and overpressure characteristics in gas explosions through physical and mathematical models; record flame propagation speed, analyze flame behavior, and pay attention to the conditions of flame quenching and acceleration; monitor the pressure changes inside the system and evaluate the pressure trends of different explosion scenarios; use data analysis to extract flame speed, overpressure and temperature characteristics, analyze the stability, propagation mode and mutation behavior of the flame, identify the influence of rigid porous materials on gas explosion flames, and evaluate their barrier properties;

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

[0013] Furthermore, in step S1, a median filtering method is used to perform image filtering, and random noise is removed by replacing each pixel value with the median value of pixels in its neighborhood.

[0014] Furthermore, in step S1, a watershed algorithm is used to perform 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 the microstructure characteristics of the rigid porous material are extracted.

[0015] Furthermore, the three-dimensional digital reconstruction technology in step S1 is to integrate the processed slice data using three-dimensional reconstruction software and generate a three-dimensional digital model using Marching Cubes algorithm.

[0016] Furthermore, in step S2, a grid drawing tool is used to draw the computational grids of the porous material area and the gas-enriched area. The principle is to gradually refine and adapt the input geometric shape based on a preliminarily generated coarse grid.

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

[0018] S31: Constructing FGM combustion model: combining GRI-Mech3.0 detailed chemical reaction mechanism and Chem1D to generate a one-dimensional PDF data table containing laminar combustion velocity and component concentration; interpolating the PDF query table with one-dimensional information into a 4D FGM query table; importing the PDF query 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 enrichment degree of oxygen 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 the second-order upwind scheme is used to spatially discretize energy, momentum, process variables, and average mixing fraction.

[0020] S33: LES is used as the turbulence model in numerical calculations, and Smagorinsky-Lilly is used as the sub-grid scale model to capture the turbulence characteristics of gas explosion flames before and after passing through rigid porous materials;

[0021] S34: The flame thickening model is used to regard the flame as a reaction zone with a certain thickness. It is used to describe and simulate the thickness of the flame and its influence on the combustion process.

[0022] Furthermore, in step S31, the GRI-Mech3.0 chemical reaction mechanism includes reactants and products, which are used to simulate the combustion characteristics of various fuels; the Chenm1D is used for one-dimensional combustion simulation, which decouples time and space variables, uses numerical methods to simulate the one-dimensional flame structure and combustion process, and analyzes the distribution of temperature, concentration and reaction rate.

[0023] Further, in step S34, the flame thickness, adiabatic flame temperature and laminar flame speed 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 in step S4 is reflected in the macroscopic characteristics of the flame; when the flame propagation speed is reduced and quenching occurs after passing through the porous medium area, it indicates that the porous material has a good suppression effect on the gas explosion; when the flame can pass through the porous medium area and is accompanied by flame acceleration, it indicates that the porous material has failed to suppress the gas explosion flame and cannot play a good suppression role.

[0025] The beneficial effects of the present invention are:

[0026] 1. Compared with experimental testing methods, the simulation evaluation method for the mutation of gas explosion flame behavior induced by rigid porous materials proposed in the present invention is safer and more efficient for the evaluation process of rigid porous medium explosion barrier performance and flame mutation behavior. In addition, the evaluation method does not require the construction of an expensive experimental platform, has a low investment cost, is simple and convenient to operate, and greatly simplifies the evaluation process of rigid porous material explosion barrier performance.

[0027] 2. The simulation evaluation method for the mutation of flame behavior of gas explosion induced by rigid porous materials proposed in the present invention has high practical value. The three-dimensional porous medium model is obtained by performing X-ray CT scanning on the rigid porous medium to be evaluated, and then a series of numerical calculation methods such as computational grid construction and combustion model construction are used to obtain the flame mutation behavior of this type of rigid porous medium for gas explosions of different types and scenarios and evaluate its explosion-proof performance.

[0028] 3. The present invention is mainly used in the field of mine safety prevention and control, and 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. The present invention solves the technical problems of uncontrollable explosion risks and high evaluation costs in the current rigid porous material evaluation process, and fills the gap in evaluating rigid porous materials induced flame behavior mutations and their explosion-proof performance through numerical simulation.

[0029] In summary, the present invention has the advantages of simple operation and high prediction accuracy. By establishing a three-dimensional real geometric model of porous media, accurate and efficient evaluation of the sudden change of flame behavior induced by different types of rigid porous media and their explosion-proof performance can be achieved.

[0030] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0032] Figure 1 It is a flow chart of a simulation evaluation method for a rigid porous material-induced gas explosion flame behavior mutation according to an embodiment of the present invention;

[0033] Figure 2 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 is a schematic diagram of a geometric model of a porous medium after three-dimensional reconstruction in an embodiment of the present invention;

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

[0036] Figure 5It is a three-dimensional flame temperature rendering cloud map obtained by simulation of the present invention;

[0037] Figure 6 It is a two-dimensional flame temperature slice cloud diagram obtained by simulation of the present invention;

[0038] Figure 7 is an explosion overpressure curve diagram obtained by simulation of the present invention;

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

[0040] Fig. 9 It is a flame propagation speed curve diagram obtained by simulation of the present invention. DETAILED DESCRIPTION

[0041] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways 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 only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0042] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, so the figures only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0043] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0044] like Figure 1 As shown, the present invention provides a simulation evaluation method for a rigid porous material-induced sudden change in gas explosion flame behavior, comprising the following steps:

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

[0046] like Figure 2 As shown, X-ray CT scanning technology selects a high-energy X-ray CT scanner to ensure that it can perform high-quality scans at micron-level resolution. The equipment is calibrated before use, including the adjustment of the voltage and current of the X-ray source and the sensitivity of the detector to ensure the accuracy of the data. The slice thickness is controlled at 0.1mm to ensure the acquisition of high-resolution data. A 360-degree full-range scan is applied to collect multiple sets of two-dimensional slice data of the sample to ensure that all areas of the material are covered. After each scan, the data is stored in DICOM format for subsequent processing and analysis.

[0047] The image filtering technology used in this step specifically adopts the median filtering method. This method effectively removes random noise, especially salt and pepper noise, by replacing each pixel value with the median value of the pixels in its neighborhood. This method can maintain the edge features of the image, thereby providing an accurate model in the subsequent processing stage.

[0048] The image segmentation technology in this step specifically uses the watershed algorithm. This method separates different areas in the image based on image gradient information. By setting an appropriate threshold, the pore structure of the rigid porous material can be clearly distinguished from the solid matrix, and the microstructural characteristics of the rigid porous material can be extracted. It can effectively capture small features and provide accurate shape information for subsequent three-dimensional digital reconstruction.

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

[0050] Step 2. Construction of computational grid and fluid domain for rigid porous materials: The underground tunnel is simplified into a rectangular structure according to a certain ratio. According to the actual position of the porous material for explosion isolation, the three-dimensional high-precision digital model of the porous material described in step 1 is embedded into the underground tunnel. The computational grid of the porous material area and the gas-rich area is drawn using the open source mesh drawing tool SnappyHexMesh, and the boundary conditions of the area are named to construct the computational grid and fluid domain for rigid porous materials. Figure 4 is a schematic diagram of the computational mesh of a rigid porous material drawn using the SnappyHexMesh tool in an embodiment of the present invention, and finally obtained 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 principle of the SnappyHexMesh mesh drawing tool is to gradually refine and adapt the input geometry based on an initially generated coarse mesh. It combines the advantages of hexahedral meshes with mesh refinement technology to generate smooth and consistent meshes on complex boundaries. This tool can accurately and efficiently construct high-quality computational meshes containing rigid porous materials.

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

[0053] Step 301, FGM combustion model construction: Combine the detailed chemical reaction mechanism of GRI-Mech3.0 and Chem1D to generate a one-dimensional PDF data table containing parameters such as laminar combustion velocity and component concentration. Use Python code to interpolate the PDF query table with one-dimensional information into a 4D FGM query table. Import the PDF query table into the simulation software, set the type and component concentration of combustible gas according to different explosion states, and set the component concentration of oxygen and nitrogen according to the enrichment degree of oxygen during the explosion.

[0054] GRI-Mech3.0 chemical reaction mechanism is a detailed chemical mechanism for combustion and chemical reaction kinetics, which is widely used in flame modeling. It contains 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 process, and analyzes 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 energy equation, momentum equation and mass equation are mainly solved. The SIMPLE pressure-velocity coupling algorithm is used to participate in the solution of the simulation process, and the second-order upwind format 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, so as to accurately evaluate the flame mutation behavior, LES is used as the turbulence model in the numerical calculation, and Smagorinsky-Lilly is used as the sub-grid scale model.

[0057] Step 304, flame thickening model construction: The flame thickening model is written into a user-defined function using C++ language to accurately analyze the flame surface structure at a relatively coarse grid scale. Before the flame thickening model is established, the flame thickness, adiabatic flame temperature and laminar flame speed of the gas / air mixture to be calculated need to be calculated using the open source chemical reaction kinetics software Cantera. The core idea of ​​the flame thickening model is to regard the flame as a reaction zone with a certain thickness, which is mainly used to describe and simulate the thickness of the flame and its influence on the combustion process.

[0058] Step 4. Numerical simulation solution and flame propagation behavior evaluation: After completing the relevant pre-processing steps, solve the constructed geometric model and numerical model to obtain the gas explosion flame, flow field and overpressure characteristics under the action of rigid porous materials. During the simulation solution process, record the flame propagation speed and analyze the flame behavior under different conditions. Pay special attention to the occurrence time and conditions of flame quenching and flame acceleration. Monitor the pressure changes inside the system and analyze the pressure change trend under different explosion scenarios. Appendix Figure 5 and attached Figure 6 They are respectively a three-dimensional flame temperature rendering cloud map and a two-dimensional flame temperature slice cloud map obtained by the simulation of the present invention; the two groups of working conditions in the figure correspond to two different porous material thicknesses. From the flame temperature evaluation results, it can be seen that the thinner rigid porous material causes the flame to accelerate, and the explosion barrier effect of the porous material fails. The thicker rigid porous material quenches the flame, and the porous medium successfully blocks the explosion. It can be seen that the simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation proposed in the present invention can well carry out accurate evaluation of the acceleration and quenching behavior of the flame.

[0059] Data analysis tools are used to extract key features such as flame position, explosion overpressure, flame speed, etc. in the simulation data, and analyze the stability, propagation mode and mutation behavior of the flame. The mutation law of the flame behavior induced by the rigid porous material in gas explosion can be obtained and the explosion barrier performance of the rigid porous material can be evaluated. Figure 7 , Attachment Figure 8 and attached Fig. 9It is the explosion overpressure, flame propagation position and flame propagation speed data under different flame mutation behaviors obtained by data analysis tools. In addition to judging the flame behavior mutation through the above-mentioned flame three-dimensional rendering cloud map and two-dimensional temperature cloud map, the flame behavior mutation mode can also be judged through the quantitative data such as explosion overpressure, flame propagation position and flame propagation speed, and the explosion barrier performance of the rigid porous medium can be further evaluated. The evaluation of the gas explosion suppression effect and flame mutation behavior of porous materials is mainly reflected in the macroscopic characteristics of the flame. When the flame propagation speed decreases and quenching occurs when passing through the porous medium area, it shows that the porous material has a good suppression effect on the gas explosion. When the flame can pass through the porous medium area and is accompanied by flame acceleration, the suppression effect of the porous material on the gas explosion flame fails and cannot play a good suppression role.

[0060] Step 5: Replace the porous material to be evaluated and repeat steps 1 to 4, select the appropriate gas component and set the oxygen and nitrogen component concentrations according to the gas enrichment level. The inhibitory effect of different types of rigid porous materials on various degrees of gas explosion and the influence of flame mutation behavior can be obtained.

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

[0062] In the above-described embodiments, although the invention has been described in conjunction with specific embodiments of the invention, many substitutions, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. For example, other storage structures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed. Embodiments of the invention are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of the appended claims.

[0063] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, any one of the methods in this embodiment is implemented.

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

[0065] The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes any one of the methods in this embodiment.

[0066] The computer-readable storage medium in this embodiment can be understood by ordinary technicians in this field: all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

[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 with each other. The memory is used to store computer programs, the communication interface is used to communicate, and the processor and the transceiver are used to run computer programs so that the electronic terminal executes each step of the above method.

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

[0069] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0070] The present invention can be used in many general or special computing system environments or configurations, such as personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and the like.

[0071] The present invention may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located 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 solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A simulation evaluation method for the sudden change of gas explosion flame behavior induced by rigid porous materials, characterized by: The following steps are involved: S1: Constructing a physical model of rigid porous materials: X-ray CT scanning of rigid porous materials is performed to obtain a two-dimensional slice image of the rigid porous materials. After image filtering and image segmentation, a 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 of rigid porous materials: According to the actual position of the porous material for explosion isolation, the three-dimensional digital model of the rigid porous material is embedded into the underground tunnel model, and then the computational grids of the porous material area and the gas-rich area are drawn, and the boundary conditions of the area are named; S3: Construct a numerical model for explosion isolation of rigid porous materials, including: constructing a 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 thickness of the flame and its influence on the combustion process; S4: Evaluate numerical simulation solutions and flame propagation behavior: Solve the flame, flow field and overpressure characteristics in gas explosions through physical and mathematical models; record flame propagation speed, analyze flame behavior, and pay attention to the conditions of flame quenching and acceleration; monitor the pressure changes inside the system and evaluate the pressure trends of different explosion scenarios; use data analysis to extract flame speed, overpressure and temperature characteristics, analyze the stability, propagation mode and mutation behavior of the flame, identify the influence of rigid porous materials on gas explosion flames, and evaluate their barrier properties; S5: Replace the porous material to be evaluated and repeat steps S1-S4, select appropriate gas components and set the component concentrations of oxygen and nitrogen according to the enrichment degree of the gas, and obtain the inhibitory effect of different types of rigid porous materials on various degrees of gas explosion and the influence of flame mutation behavior.

2. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 1 is characterized by: In step S1, a median filtering method is used to filter the image, and random noise is removed by replacing each pixel value with the median value of the pixels in its neighborhood.

3. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 1 is characterized by: In step S1, a watershed algorithm is used to perform 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 the microstructure characteristics of the rigid porous material are extracted.

4. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 1 is characterized by: The three-dimensional digital reconstruction technology in step S1 is to integrate the processed slice data using three-dimensional reconstruction software and generate a three-dimensional digital model using the Marching Cubes algorithm.

5. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 1 is characterized by: In step S2, a grid drawing tool is used to draw the computational grids of the porous material area and the gas-enriched area. The principle is to gradually refine and adapt the input geometric shape based on a preliminarily generated coarse grid.

6. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 1 is characterized by: Step S3 specifically includes the following steps: S31: Constructing FGM combustion model: combining GRI-Mech3.0 detailed chemical reaction mechanism and Chem1D to generate a one-dimensional PDF data table containing laminar combustion velocity and component concentration; interpolating the PDF query table with one-dimensional information into a 4D FGM query table; importing the PDF query 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 enrichment degree of oxygen 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 the second-order upwind scheme is used to spatially discretize energy, momentum, process variables, and average mixing fraction. S33: LES is used as the turbulence model in numerical calculations, and Smagorinsky-Lilly is used as the sub-grid scale model to capture the turbulence characteristics of gas explosion flames before and after passing through rigid porous materials; S34: The flame thickening model is used to regard the flame as a reaction zone with a certain thickness. It is used to describe and simulate the thickness of the flame and its influence on the combustion process.

7. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 6 is characterized by: In step S31, the GRI-Mech3.0 chemical reaction mechanism includes reactants and products, and is used to simulate the combustion characteristics of various fuels; the Chenm1D is used for one-dimensional combustion simulation, which decouples time and space variables, uses numerical methods to simulate the one-dimensional flame structure and combustion process, and analyzes the distribution of temperature, concentration and reaction rate.

8. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 6 is characterized by: In step S34, the flame thickness, adiabatic flame temperature and laminar flame speed of the gas or air mixture are first calculated to construct the flame thickening model.

9. The simulation evaluation method for the rigid porous material-induced gas explosion flame behavior mutation according to claim 1 is characterized by: The evaluation of the gas explosion suppression effect and flame mutation behavior of the porous material in step S4 is reflected in the macroscopic characteristics of the flame; when the flame propagation speed is reduced and quenching occurs when passing through the porous medium area, it indicates that the porous material has a good suppression effect on the gas explosion; when the flame can pass through the porous medium area and is accompanied by flame acceleration, it indicates that the porous material has failed to suppress the gas explosion flame and cannot play a good suppression role.

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