A similar simulation test device and method for visualizing coalfield fire evolution process

Abstract

The present invention belongs to the technical field of coalfield fire evolution analysis and specifically provides a similarity simulation test device and method for visualizing the evolution of coalfield fires. The test device includes a test bench, a physical similarity model, a fiber Bragg grating (FBG) integrated temperature and stress monitoring system, a multi-gas monitoring system, an image and video monitoring system, and a computer analysis system. Multiple open frames are sequentially fixed to form a test chamber, the physical similarity model is positioned within the chamber, and the chamber's inclination is adjusted via an inclination adjustment mechanism. The chambers are connected to a gas supply system and an ignition system, and the fiber Bragg grating integrated temperature and stress monitoring system, the multi-gas monitoring system, and the image and video monitoring system are each signal-connected to the computer analysis system. The present invention can visualize the evolution of coalfield fires under different conditions and enable real-time monitoring of the changing patterns of temperature, seepage, and fracture fields during the evolution of coalfield fires under different conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of coalfield fire evolution analysis, and in particular relates to a similar simulation test device and method for visualizing the evolution process of coalfield fire. Background Art

[0002] Coalfield fires are a prominent problem due to arid climate and geological conditions. In some areas, thick coal seams, shallow burial depths, widespread outcrops, short spontaneous combustion periods, and the indiscriminate mining and excavation of small coal mines have resulted in most coal seams being highly susceptible to oxidation and spontaneous combustion, making them difficult to completely control. Furthermore, existing fire-fighting technologies (such as stripping and grouting) face numerous limitations in field application, making them ineffective in addressing the complex combustion conditions and often lacking systematic and targeted control solutions. Therefore, in-depth research on the combustion evolution of coalfield fire zones under the influence of multiple fields, particularly the development of a simulated experimental device for visualizing the evolution of coalfield fires and proposing targeted control solutions, is crucial for understanding the evolution mechanisms of coalfield fire zones under the influence of multiple fields and guiding coalfield fire prevention and control.

[0003] At present, the research on the combustion evolution process of coalfield fire areas mainly includes:

[0004] 1) In terms of physical simulation, the researchers constructed a similar model consisting of an insulating base, a coal seam, and multiple layers of overburden within the experimental device, and used an electric heating system to simulate the actual combustion environment;

[0005] 2) In terms of numerical simulation, computational simulation technology is used to conduct coupled analysis of the temperature distribution in the fire zone, fracture seepage, and rock formation deformation to reveal the laws of combustion expansion;

[0006] 3) For on-site monitoring, a distributed temperature sensor network, gas composition analyzers, and stress monitoring devices are used to locate fire sources and assess combustion status;

[0007] 4) In terms of engineering control, fire zone control is implemented by combining comprehensive measures such as excavation, grouting and covering.

[0008] However, there are still the following shortcomings:

[0009] (1) Most existing studies have inferred the development process of cracks in coalfield fire areas by collecting stress data during the combustion evolution process. They have failed to truly and intuitively reflect the crack development process, establish a corresponding crack network, and achieve effective monitoring and visualization of crack development in coalfield fires.

[0010] (2) Currently, most studies on physical similarity simulation of coalfield fire areas monitor parameters such as temperature and gas concentration to infer the combustion evolution process of coalfield fire areas, but fail to observe and record the evolution process of coalfield fires and realize its visualization.

[0011] In summary, although the existing technology has accumulated a certain experimental and theoretical basis, it still lacks sufficient originality and comprehensiveness to realize the effective monitoring of crack development during the combustion evolution of coalfield fire areas and the visualization of the coalfield fire evolution process. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide a similar simulation test device and method for visualizing the evolution process of coalfield fire in order to solve the problems raised in the above-mentioned background technology.

[0013] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0014] The first aspect is a similar simulation test device for visualizing the evolution process of coalfield fire, including a test bench, a physical similarity model, a fiber Bragg grating temperature and stress integrated monitoring system, a multi-gas monitoring system, an image and video monitoring system, and a computer analysis system;

[0015] The test bench is connected to a test box, which is formed by assembling a plurality of open frames in sequence. The open frames are slidably mounted on the test bench, and slots for clamping the thermal insulation glass are provided on both sides of the open frames.

[0016] The physical similarity model is, from bottom to top, the first rock layer, the coal layer, the second rock layer, the third rock layer, the fourth rock layer and the fifth rock layer. The physical similarity model is arranged in a test box. The test bench is also connected to an inclination adjustment mechanism for adjusting the inclination of the test box.

[0017] The test bench is also provided with an air supply system and an ignition system connected to the test box. The air supply system is used to supply air to the test box, and the ignition system is used to ignite a physical similarity model to simulate a coalfield fire, which is used for a similar simulation test of the coalfield fire evolution process.

[0018] The fiber Bragg grating temperature and stress integrated monitoring system is used to monitor in real time the temperature and stress of the physical similarity model in the test box during a similar simulation test of the coalfield fire evolution process; the multi-gas monitoring system is used to monitor the gas concentration value in the test box after the physical similarity model generates cracks in the similar simulation test of the coalfield fire evolution process; the image and video monitoring system is used to monitor the changes in the physical similarity model in the similar simulation test of the coalfield fire evolution process, and to extract the opening frame after the test is completed to collect two-dimensional slice images; the fiber Bragg grating temperature and stress integrated monitoring system, the multi-gas monitoring system, and the image and video monitoring system are respectively connected to the computer analysis system by signal. The computer analysis system has a built-in dynamic visualization model of multi-physical field coupling, and the visualization model has a three-dimensional crack field evolution model embedded in it. Data analysis and visualization processing operations are performed through the computer analysis system.

[0019] As a further illustration of the present invention, a plurality of screw holes are provided on the outer side of the open frame, and two adjacent open frames can be fixed by the cooperation of bolts and the screw holes. The open frame is also provided with a plurality of detection holes.

[0020] As a further explanation of the present invention, a group of pulleys are provided at the bottom of each open rack, and a plurality of parallel rail grooves are provided on the base. A group of pulleys are slidably connected in each rail groove, and the pulleys are self-locking pulleys. The inner surface of the open rack is also covered with high-temperature resistant fiber cotton.

[0021] As a further explanation of the present invention, the inclination adjustment mechanism includes a lifting hydraulic cylinder and a hydraulic pump. There are three lifting hydraulic cylinders, one of which is arranged at the side end of the base, and the other two lifting hydraulic cylinders are arranged below the test box on the base. The telescopic shafts of the lifting hydraulic cylinders are respectively connected to the test box, and the lifting hydraulic cylinders are powered by a hydraulic pump.

[0022] As a further illustration of the present invention, the gas supply system includes an oxygen cylinder, a nitrogen cylinder, a gas flow meter and an air compressor. The oxygen cylinder and the nitrogen cylinder are respectively connected to the air compressor. The gas outlet sections of the oxygen cylinder and the nitrogen cylinder are also respectively connected to a gas flow meter. The input gas is pressurized by the air compressor to reach a specified pressure and then input into the test chamber.

[0023] As a further explanation of the present invention, the ignition system includes a digital electronic temperature controller, a heating rod and a temperature sensor. The heating rod and the temperature sensor are respectively arranged in a physically similar model. The heating rod and the temperature sensor are connected to the digital electronic temperature controller. The temperature of the heating rod is set by the digital electronic temperature controller and monitored by the temperature sensor.

[0024] As a further illustration of the present invention, the fiber Bragg grating temperature and stress integrated monitoring system includes an ultra-high temperature fiber Bragg grating sensor, a fiber Bragg grating network analyzer and a terminal box;

[0025] The ultra-high temperature fiber Bragg grating sensor can monitor the temperature and stress of the physical similarity model in the test box during a similar simulation test of the coalfield fire evolution process. The ultra-high temperature fiber Bragg grating sensor is connected to a fiber Bragg grating network analyzer through a terminal box, and the fiber Bragg grating network analyzer is connected to a computer analysis system.

[0026] As a further explanation of the present invention, the multi-gas monitoring system consists of a multi-gas monitor and a signal line. The multi-gas monitor is connected to the air outlet at the top of the test box. When the physical similarity model in the test box produces cracks in a similar simulation test of the coalfield fire evolution process, the detection head of the multi-gas monitor is inserted into the crack to monitor and display the concentration values ​​of CO, C2H4, CH4, CO2, C2H6, C2H2, O2, H2, and H2S gases, and transmit the data to the computer analysis system through the signal line. The image and video monitoring system consists of a bracket and three dual-spectrum high-definition cameras arranged on the bracket. The dual-spectrum high-definition cameras record the similar simulation test process of the coalfield fire evolution process in the test box, and transmit the data to the computer analysis system.

[0027] As a further illustration of the present invention, the computer analysis system records data obtained by the fiber Bragg grating temperature and stress integrated monitoring system, the multi-gas monitoring system, and the image and video monitoring system.

[0028] In a second aspect, a similar simulation test method for visualizing the evolution process of a coalfield fire comprises the following steps:

[0029] S1. Calculate and design the dimensions and conditions of a physical similarity model of an actual experimental coalfield fire based on similarity criteria. Construct a test bench based on the dimensions and conditions of the physical similarity model. Assemble and secure multiple opening frames in sequence, insert insulating glass onto the outermost opening frame to form a test chamber. Place the physical similarity model within the chamber, and use the inclination adjustment mechanism to adjust the chamber to a set inclination angle.

[0030] S2. Arrange the fiber Bragg grating temperature and stress integrated monitoring system in the physical similarity model to perform temperature and stress monitoring;

[0031] S3. After the physical similarity model is allowed to air dry and solidify, the fiber Bragg grating temperature and stress integrated monitoring system, the multi-gas monitoring system, and the image and video monitoring system are connected to the computer analysis system respectively;

[0032] S4. Supplying gas to the physical similarity model through the gas supply system and igniting the physical similarity model through the ignition system to conduct a similar simulation test of the coalfield fire evolution process. At this time, the fiber Bragg grating temperature and stress integrated monitoring system and the image and video monitoring system are activated to monitor data. When the coalfield fire area in the test chamber collapses and cracks are generated, the detection head of the multi-gas monitor of the multi-gas monitoring system is inserted into the crack to monitor the gas concentration value.

[0033] S5. After the combustion of the physical similarity model is completed, the test box is allowed to stand and cool naturally to room temperature. Insulation glass is inserted into the slots on both sides of each opening frame. The physical similarity model after combustion is sliced. The multiple opening frames are disassembled and assembled. The image and video monitoring system is used to record the two-dimensional slice image of each opening frame after it slides out. The two-dimensional slice image data set is obtained and transmitted to the computer analysis system. The computer analysis system uses Matlab to reconstruct the three-dimensional crack model of the two-dimensional slice image data set. ParaView is used to render and analyze the spatiotemporal distribution data measured by each system to construct a dynamic visualization model of multi-physical field coupling.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] 1. The present invention can realize the visualization of the evolution process of coalfield fires under different conditions. Through the fiber Bragg grating temperature and stress integrated monitoring system, multi-gas monitoring system, image and video monitoring system and computer analysis system, it can realize real-time monitoring of the changing laws of temperature field, seepage field and fracture field during the evolution process of coalfield fires under different conditions.

[0036] 2. After the experiment, the test bench in this invention can extract each open frame, collect a 2D slice image dataset, reconstruct the internal fracture field using Matlab, and construct a 3D fracture field evolution model. This allows visualization of the distribution and size of fractures within the coalfield fire zone during its evolution. This 3D fracture model can be imported into Fluent or Comsol software to provide data support for numerical simulations related to coalfield fire zone evolution. Using image and video monitoring systems to record surface fracture development and smoke diffusion patterns, the impact of fire on the internal structure of the coal body can be visually observed. The surface temperature distribution of the coalfield is captured in real time, indicating high-temperature areas and fire spread trends. ParaView is used to render and analyze the spatiotemporal distribution data measured by each system, constructing a dynamic visualization model coupled with multiple physical fields to visualize the evolution of coalfield fires. By superimposing high-temperature areas and fracture expansion, "critical states" such as temperature mutation points or fracture penetration zones can be located, providing a scientific basis for early warning. This more intuitively reveals the coupled mechanism of thermal-seepage-fracture interaction in fire evolution, deepening the understanding of the self-sustaining mechanism of coalfield fires. Providing a visual decision-making platform for proactive prevention and control, the visualization model can intuitively display the distribution of high-temperature areas and fissures in coalfields, helping researchers accurately locate fire risk areas and providing a basis for developing targeted prevention and control measures. Assessing the potential damage caused by coalfield fires, including the extent of fire spread and the degree of damage to the surrounding environment, can provide important reference for developing firefighting plans. For example, the location and amount of firefighting grouting can be determined based on the distribution of fissures, improving firefighting efficiency and guiding the targeted implementation of engineering measures such as grouting and barrier insulation. Furthermore, the large amount of accumulated data can provide training samples for machine learning predictive models, promoting the development of intelligent fire prevention and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0038] Figure 2 It is a schematic diagram of an open frame of the present invention.

[0039] Figure 3 It is a schematic diagram of the physical similarity model of the present invention after angle adjustment.

[0040] Figure 4 It is a schematic diagram of a single open frame of the present invention sliding out.

[0041] Figure 5 Schematic diagram of the gas supply system of the present invention.

[0042] Description of reference numerals:

[0043] 1-test bench; 11-base; 111-groove rail; 12-opening frame; 121-card slot; 122-pulley; 123-detection hole; 124-screw hole; 13-insulating glass; 14-hydraulic lifting system; 141-hydraulic pump; 142-lifting hydraulic cylinder; 151-oxygen cylinder; 152-nitrogen cylinder; 153-gas flow meter; 154-air compressor; 15-gas supply system; 16-ignition system; 161-digital display electronic temperature controller; 162-heating rod; 16 3-temperature sensor; 2-physical similarity model; 21-first rock layer; 22-coal layer; 23-second rock layer; 24-third rock layer; 25-fourth rock layer; 26-fifth rock layer; 3-fiber Bragg grating temperature and stress integrated monitoring system; 31-ultra-high temperature fiber Bragg grating sensor; 32-fiber Bragg grating network analyzer; 33-terminal box; 4-multi-gas monitoring system; 5-image and video monitoring system; 51-dual-spectrum high-definition camera; 52-bracket; 6-computer analysis system. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] like Figure 1-5 As shown, the present invention provides a technical solution: a visual coalfield fire evolution process similarity simulation test device, including a test bench 1, a physical similarity model 2, a fiber Bragg grating temperature and stress integrated monitoring system 3, a multi-gas monitoring system 4, an image and video monitoring system 5 and a computer analysis system 6.

[0046] The test bench 1 includes a base 11, an open frame 12, an insulating glass 13 and a tilt adjustment mechanism 14. The base 11 is provided with a plurality of mutually parallel rail grooves 111, and each of the rail grooves 111 is slidably connected to an open frame 12. A pulley 122 is provided at the bottom of the open frame 12, and the pulley 122 is slidably connected to the rail groove 111. The pulley 122 is a self-locking pulley.

[0047] The size of the base 11 is 4000mm×2000mm×150mm, the size of the rail groove 111 on the base 11 is 3600mm×100mm×100mm, and the size of the open frame 12 is 1800mm×120mm×1800mm.

[0048] The inner surface of the open frame 12 is also covered with high-temperature resistant fiber cotton. A plurality of screw holes 124 are also provided on the outer side of the open frame 12. The spacing between two adjacent screw holes 124 is 180 mm. Two adjacent open frames 12 can be fixed by the cooperation of bolts and screw holes 124. A plurality of open frames 12 are assembled and fixed in sequence to form a test box. The open frame 12 is a U-shaped frame, and a card slot 121 is further provided on both sides of the open frame 12. The thermal insulation glass 13 is carded in the card slot 121.

[0049] The physical similarity model 2 comprises, from bottom to top, a first rock layer 21 , a coal layer 22 , a second rock layer 23 , a third rock layer 24 , a fourth rock layer 25 and a fifth rock layer 26 , and the physical similarity model 2 is arranged in a test box.

[0050] The test bench 1 is also connected to a tilt adjustment mechanism 14, which includes a lifting hydraulic cylinder 142 and a hydraulic pump 141. Three lifting hydraulic cylinders 142 are provided, one of which is provided at the side end of the base 11, and the other two lifting hydraulic cylinders 142 are provided below the test box on the base 11. The telescopic shafts of the lifting hydraulic cylinders 142 are respectively connected to the test box, and the lifting hydraulic cylinders 142 are powered by the hydraulic pump 141. The tilt angle α of the test box is adjusted through the tilt adjustment mechanism 14, and the adjustment range is 0~90 degrees, thereby realizing the simulated evolution of coalfield fire zones with different tilt angles.

[0051] The test bench 1 is also provided with an air supply system 15 and an ignition system 16 connected to the test box;

[0052] The gas supply system 15 includes an oxygen cylinder 151, a nitrogen cylinder 152, a gas flow meter 153 and an air compressor 154. The oxygen cylinder 151 and the nitrogen cylinder 152 are respectively connected to the air compressor 154. The gas outlet sections of the oxygen cylinder 151 and the nitrogen cylinder 152 are also connected to the gas flow meter 153 respectively. The input gas is pressurized by the air compressor 154 to reach the specified pressure and then input into the test box.

[0053] The ignition system 16 includes a digital electronic temperature controller 161, a heating rod 162 and a temperature sensor 163. The heating rod 162 and the temperature sensor 163 are respectively arranged in the physical similarity model 2. The heating rod 162 and the temperature sensor 163 are connected to the digital electronic temperature controller 161. The temperature of the heating rod 162 is set by the digital electronic temperature controller 161 and monitored by the temperature sensor 163.

[0054] The fiber Bragg grating temperature and stress integrated monitoring system 3 is used to monitor in real time the temperature and stress of the physical similarity model 2 in the test box during a similar simulation test of the coalfield fire evolution process;

[0055] The multi-gas monitoring system 4 is used to monitor the gas concentration value in the test box after the physical similarity model 2 is cracked in a similar simulation test of the coalfield fire evolution process;

[0056] The image and video monitoring system 5 is used to monitor the changes of the physical similarity model 2 in the similarity simulation test of the coalfield fire evolution process, and to extract the opening frame 12 after the test to collect two-dimensional slice images;

[0057] The fiber Bragg grating temperature and stress integrated monitoring system 3, the multi-gas monitoring system 4, and the image and video monitoring system 5 are respectively connected to the computer analysis system 6 by signals. The computer analysis system 6 has a built-in dynamic visualization model of multi-physical field coupling, and a three-dimensional fracture field evolution model is embedded in the visualization model. Data analysis and visualization processing operations are performed through the computer analysis system 6.

[0058] The fiber Bragg grating temperature and stress integrated monitoring system 3 includes an ultra-high temperature fiber Bragg grating sensor 31, a fiber Bragg grating network analyzer 32 and a terminal box 33. The open frame 12 is also provided with a plurality of detection holes 123, and the spacing between two adjacent detection holes 123 is 180 mm. The ultra-high temperature fiber Bragg grating sensor 31 can monitor the temperature and stress in the test chamber. The ultra-high temperature fiber Bragg grating sensor 31 is connected to the fiber Bragg grating network analyzer 32 through the terminal box 33, and the fiber Bragg grating network analyzer 32 is connected to the computer analysis system 6.

[0059] The multi-gas monitoring system 4 consists of a multi-gas monitor and a signal line. The multi-gas monitor model is GREENG7000. The multi-gas monitor is connected to the air outlet on the top of the test box. When a crack occurs in the test box, the detection head is inserted into the crack to monitor and display the concentration values ​​of CO, C2H4, CH4, CO2, C2H6, C2H2, O2, H2, and H2S gases, and transmit the data to the computer analysis system 6 through the signal line. The image and video monitoring system 5 consists of a bracket 52 and three dual-spectrum high-definition cameras 51 arranged on the bracket 52. The three dual-spectrum high-definition cameras 51 are respectively arranged on the side and directly above the two insulating glasses of the test box. The test process in the test box is recorded by the dual-spectrum high-definition camera 51, and the data is transmitted to the computer analysis system 6. The dual-spectrum high-definition camera model 51 can be the intrinsically safe thermal imaging dual-spectrum integrated camera HB-8501R-F9432-T9310. It combines visible light and infrared thermal imaging technology to capture the temperature distribution on the coal field surface in real time, generate a thermal map, and superimpose it with the visible light video to intuitively display the high-temperature area and fire spread trend, and record the development of surface cracks and the law of smoke diffusion.

[0060] The computer analysis system 6 is used to record the temporal and spatial distribution of temperature, stress, cracks, gas concentration values, images and other data obtained by the fiber Bragg grating temperature and stress integrated monitoring system 3, the multi-gas monitoring system 4, and the image and video monitoring system 5. The computer analysis system 6 has a built-in dynamic visualization model of multi-physical field coupling, and a three-dimensional crack field evolution model is embedded in the visualization model.

[0061] The multi-physics field coupling dynamic visualization model uses ParaView to dynamically render the collected stress, temperature, crack and gas concentration multi-physics field time series data, ensures the consistency of the time step and spatial grid of each physical field through data alignment and fusion, and uses Temporal Interpolator or Resample filter to process non-uniform data; adopts a multi-field coupling visualization strategy, such as using Volume Rendering to highlight the high-temperature area of ​​the temperature field, displaying the displacement deformation of the crack field through Warp by Vector, generating dynamic streamlines of gas concentration with Stream Tracer, and adjusting the transparency of each field through Opacity to achieve superimposed display.

[0062] Then, use the timeline control to drag the slider or write a Python script to accurately retrace the state at any time, and use Animation View to record the measured evolution process and export it as an interactive HTML report or high-resolution animation to achieve dynamic visualization of its multi-physics field coupling.

[0063] The three-dimensional crack field evolution model uses Matlab to reconstruct a three-dimensional crack model on the two-dimensional slice image data set measured by the image and video monitoring system, and reversely deduces the dynamic development process of the crack through finite element or discrete element methods, such as PFC and UDEC, to generate a time-series three-dimensional crack field evolution model;

[0064] The following is the process of constructing the three-dimensional fracture field evolution model.

[0065] ① Load image data: First, load the two-dimensional slice image dataset into Matlab. You can use the imread or dicomread function to read the image data.

[0066] ② Image preprocessing: Binarization preprocessing is performed on the loaded two-dimensional slice image, with black representing coal rock layers and white representing cracks, to improve the subsequent reconstruction effect.

[0067] ③ Create spatial voxels: Based on the size and resolution of the image, create a matching three-dimensional voxel space in Matlab to store the reconstructed image data.

[0068] ④ Implementation of the reconstruction process: Use the trained attention-based generative adversarial network SAGAN model for 3D reconstruction.

[0069] ⑤ 3D visualization and analysis: Use the 3D visualization tools in Matlab to display and analyze the reconstructed 3D images. Use functions such as isosurace or slice to display images from different perspectives and calculate the crack ratio. You can also use voxel data for other related analyses.

[0070] ⑥ Dynamic crack evolution simulation and reverse modeling: Using the final 3D reconstructed model as the boundary condition, combined with the surface crack expansion law recorded in the video and internal monitoring data, temperature gradient, and stress changes, a correlation model between crack development and internal stress field and temperature field is established. Through finite element or discrete element methods such as PFC and UDEC, the dynamic crack development process is reversely deduced to generate a time-series 3D crack field evolution model, providing data for the dynamic visualization model of multi-physics field coupling.

[0071] The dynamic visualization model of multi-physics field coupling can automatically update the rendering screen according to the real-time updated data and record the entire process. After the experiment is completed, it can be traced back to any time in real time for visualization.

[0072] In this embodiment, the attention-based generative adversarial network SAGAN model inputs Gaussian noise into the generator G to generate a fake three-dimensional image, and inputs the two-dimensional slice image into the discriminator D. During the training process, the generator G and the discriminator D are trained alternately. The generator G attempts to generate increasingly realistic fake three-dimensional images to "cheat" the discriminator D, while the discriminator D attempts to become smarter to better identify fake data. When the current epoch does not exceed the predetermined maximum number of epochs, the SAGAN model is saved, a more realistic three-dimensional model is constructed, and the image is reconstructed. When the current epoch exceeds the predetermined maximum number of epochs, Gaussian noise is again input into the generator G to generate a fake three-dimensional image, and the training is repeated until the previous epoch does not exceed the predetermined maximum number of epochs.

[0073] The generator G consists of four 3D transposed convolutional layers, eight residual blocks, a channel attention module (CTAM), and a 3D convolutional layer. The discriminator D consists of four 2D convolutional layers with ReLUs and a 2D convolutional layer. The residual blocks can mitigate the possibility of degradation. The CTAM helps the model focus on important features of the 2D slice image.

[0074] The Gaussian noise shape is 8×32×4×4×4 (batch size: 8; number of channels: 32; depth, width, and height are all 4).

[0075] The input 2D image shape of the discriminator D is 8×2×64×64 (batch size: 8; number of phases: 2; width and height are both 64).

[0076] The loss function of the SAGAN model based on the attention mechanism is as follows:

[0077] (1)

[0078] Where, represents the loss function;

[0079] Represents all false 2D slice images in the current batch The discriminator output The average value of

[0080] Represents all real 2D slice images in the current batch The discriminator output The average value of

[0081] Represents the gradient penalty term corresponding to all interpolation samples k in the current batch The average value of

[0082] is the actual data distribution;

[0083] is the generated data distribution;

[0084] represents a false two-dimensional slice image extracted from the generated false three-dimensional image;

[0085] Represents a real two-dimensional slice image;

[0086] is the distribution of the interpolated samples;

[0087] Involving and Sampling points are evenly distributed on the straight line between the paired sampling points;

[0088] is relative to k gradient;

[0089] is the weight, which is set to 10 by default.

[0090] To test the performance of the learned model, the FID value is used to measure the similarity between the two image distributions and thus evaluate the quality of the reconstructed image.

[0091] The method for conducting a similar simulation test of a coalfield fire evolution process using the above-mentioned similar simulation test device for a coalfield fire evolution process comprises the following steps:

[0092] S1. Calculate and design the dimensions and conditions of a physical similarity model 2 for an actual experimental coalfield fire based on similarity criteria. Construct a test bench 1 based on the dimensions and conditions of the physical similarity model 2. Assemble and secure multiple opening frames 12 in sequence, insert insulating glass 13 onto the two outermost opening frames 12 to form a test chamber. Place the physical similarity model 2 within the test chamber. Secure another piece of insulating glass 13 to the top of the test chamber. Use an inclination adjustment mechanism 14 to adjust the test chamber to a set inclination angle.

[0093] S2, placing the fiber Bragg grating temperature and stress integrated monitoring system 3 in the physical similarity model 2 to perform temperature and stress monitoring;

[0094] S3, after the physical similarity model 2 is allowed to air dry and solidify, the fiber Bragg grating temperature and stress integrated monitoring system 3, the multi-gas monitoring system 4 and the image and video monitoring system 5 are respectively connected to the computer analysis system 6;

[0095] S4. Supply gas to the physical similarity model 2 through the gas supply system 15, and open the ignition system 16 to ignite the physical similarity model 2 to conduct a similar simulation test of the coalfield fire evolution process. At this time, the fiber Bragg grating temperature and stress integrated monitoring system 3 and the image and video monitoring system 5 are started to monitor data. When the coalfield fire area in the test chamber collapses and cracks are generated, the detection head of the multi-gas monitor of the multi-gas monitoring system 4 is inserted into the crack to monitor the gas concentration value;

[0096] S5. After the combustion of the physical similarity model 2 is completed, the test box is allowed to stand and cool naturally to room temperature. The thermal insulation glass 13 on the top of the test box is first removed, and the thermal insulation glass 13 is inserted into the slots on both sides of each opening frame 12. The physical similarity model 2 after combustion is sliced, and the multiple assembled opening frames 12 are disassembled. The image and video monitoring system 5 is used to record the two-dimensional slice image of each opening frame 12 after sliding out, and a two-dimensional slice image data set is obtained. The two-dimensional slice image data set is transmitted to the computer analysis system 6. The computer analysis system 6 uses Matlab to reconstruct a three-dimensional crack model of the two-dimensional slice image data set, and uses ParaView to render and analyze the spatiotemporal distribution data measured by each system to construct a dynamic visualization model of multi-physical field coupling.

[0097] In summary, the present invention can realize the visualization of the evolution process of coalfield fires under different conditions. Through the fiber Bragg grating temperature and stress integrated monitoring system 3, the multi-gas monitoring system 4, the image and video monitoring system 5, and the computer analysis system 6, it can realize real-time monitoring of the changing laws of the temperature field, seepage field, and fracture field during the evolution process of coalfield fires under different conditions.

[0098] At the same time, after the experiment is completed, the test bench of the present invention can pull out each opening frame 12, reconstruct the internal crack field through Matlab, and use finite element or discrete element methods such as PFC and UDEC to reversely deduce the dynamic development process of the cracks to generate a time-series three-dimensional crack field evolution model, so that the internal crack distribution and size during the combustion evolution of the coalfield fire zone can be visualized. The three-dimensional crack model can be imported into Fluent or Comsol software to further provide data support for numerical simulation related to the evolution of coalfield fire zones; the surface crack development and smoke diffusion laws are recorded through the image and video monitoring system 5, so that the impact of the fire on the internal structure of the coal body can be intuitively observed, the temperature distribution on the coalfield surface can be captured in real time, and the high-temperature area and fire spread trend can be displayed.

[0099] ParaView renders and analyzes the spatiotemporal data measured by various systems, constructing a dynamic visualization model coupled with multiple physical fields to visualize the evolution of coalfield fires. By overlaying high-temperature areas with fracture expansion, critical states, such as temperature mutation points or fracture interpenetration, can be located, providing a scientific basis for early warning. This more intuitively reveals the coupled thermal, seepage, and fracture mechanisms in fire evolution, deepening our understanding of the self-sustaining mechanisms of coalfield fires. Providing a visual decision-making platform for proactive prevention and control, the visualization model visually displays the distribution of high-temperature areas and fractures within the coalfield, helping researchers precisely locate fire risk areas and providing a basis for developing targeted prevention and control measures. Assessing the potential hazard of coalfield fires, including the extent of fire spread and the degree of damage to the surrounding environment, provides crucial insights for developing firefighting plans. For example, the distribution of fractures can be used to determine the location and volume of firefighting grouting, improving firefighting efficiency and guiding the targeted implementation of engineering measures such as grouting and barrier injection. Furthermore, the accumulated data provides training samples for machine learning predictive models, driving the development of intelligent fire prevention and control.

[0100] Furthermore, the present invention can achieve the introduction of oxygen in a concentration range of 0-100% by adjusting the gas flow meter of the oxygen supply system, thereby simulating the on-site gas environment.

[0101] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0102] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A visual simulation test device for the evolution of coalfield fire, characterized by: It includes a test bench (1), a physical similarity model (2), a fiber Bragg grating temperature and stress integrated monitoring system (3), a multi-gas monitoring system (4), an image and video monitoring system (5) and a computer analysis system (6); The test bench (1) is connected to a test box, and the test box is formed by assembling a plurality of open frames (12) in sequence. The open frames (12) are slidably mounted on the test bench (1), and the open frames (12) are movably connected to the base (11). A group of pulleys (122) are provided at the bottom of each open frame (12). The base (11) is also provided with a plurality of mutually parallel rail grooves (111). A group of pulleys (122) are slidably connected in each of the rail grooves (111). The pulleys (122) are self-locking pulleys. The inner surface of the open frame (12) is also attached with high-temperature resistant fiber cotton. Slots (121) for clamping the thermal insulation glass (13) are also provided on both sides of the open frame (12). The physical similarity model (2) is arranged in the test box, and the test bench (1) is also connected to an inclination adjustment mechanism (14) for adjusting the inclination angle of the test box, the inclination adjustment mechanism (14) includes a lifting hydraulic cylinder (142) and a hydraulic pump (141), and three lifting hydraulic cylinders (142) are provided, one of which is arranged at the side end of the base (11), and the other two lifting hydraulic cylinders (142) are arranged below the test box on the base (11), the telescopic shafts of the lifting hydraulic cylinders (142) are respectively connected to the test box, and the lifting hydraulic cylinders (142) are powered by the hydraulic pump (141); The test bench (1) is also provided with an air supply system (15) and an ignition system (16) connected to the test box. Air is supplied to the test box through the air supply system (15), and the ignition system (16) ignites the physical similarity model (2) to simulate a coalfield fire, and is used for a similar simulation test of the coalfield fire evolution process. The fiber Bragg grating temperature and stress integrated monitoring system (3) comprises an ultra-high temperature fiber Bragg grating sensor (31), a fiber Bragg grating network analyzer (32) and a terminal box (33); The ultra-high temperature fiber Bragg grating sensor (31) can monitor the temperature and stress of the physical similarity model (2) in the test box during a similar simulation test of the coalfield fire evolution process, and the ultra-high temperature fiber Bragg grating sensor (31) is connected to a fiber Bragg grating network analyzer (32) through a terminal box (33), and the fiber Bragg grating network analyzer (32) is connected to a computer analysis system (6); The computer analysis system (6) has a built-in dynamic visualization model of multi-physical field coupling, and a three-dimensional fracture field evolution model is embedded in the visualization model. Data analysis and visualization processing operations are performed through the computer analysis system (6).

2. A visual coalfield fire evolution process similarity simulation test device according to claim 1, characterized in that: The outer side of the open frame (12) is also provided with a plurality of screw holes (124), and two adjacent open frames (12) can be fixed by the cooperation of bolts and the screw holes (124). The open frame (12) is also provided with a plurality of detection holes (123).

3. A visual coalfield fire evolution process similarity simulation test device according to claim 1, characterized in that: The gas supply system (15) includes an oxygen cylinder (151), a nitrogen cylinder (152), a gas flow meter (153) and an air compressor (154). The oxygen cylinder (151) and the nitrogen cylinder (152) are respectively connected to the air compressor (154). The gas outlet sections of the oxygen cylinder (151) and the nitrogen cylinder (152) are also respectively connected to the gas flow meter (153). The input gas is pressurized by the air compressor (154) to reach a specified pressure and then input into the test chamber.

4. A visual coalfield fire evolution process similarity simulation test device according to claim 1, characterized in that: The ignition system (16) includes a digital electronic temperature controller (161), a heating rod (162) and a temperature sensor (163), wherein the heating rod (162) and the temperature sensor (163) are respectively arranged in the physical similarity model (2), and the heating rod (162) and the temperature sensor (163) are connected to the digital electronic temperature controller (161), and the temperature of the heating rod (162) is set by the digital electronic temperature controller (161) and monitored by the temperature sensor (163).

5. The device for visualizing similar simulation of coalfield fire evolution process according to claim 1 is characterized in that: The multi-gas monitoring system (4) is composed of a multi-gas monitor and a signal line. The multi-gas monitor is connected to the gas outlet on the top of the test box. When the physical similarity model (2) in the test box generates cracks in a similar simulation test of the coalfield fire evolution process, the detection head of the multi-gas monitor is inserted into the crack to monitor and display the gas concentration value, and transmit the data to the computer analysis system (6) through the signal line. The image and video monitoring system (5) is composed of a bracket (52) and three dual-spectrum high-definition cameras (51) arranged on the bracket (52). The dual-spectrum high-definition cameras (51) record the similar simulation test process of the coalfield fire evolution process in the test box and transmit the data to the computer analysis system (6).

6. A visual coalfield fire evolution process similarity simulation test device according to claim 1, characterized in that: The computer analysis system (6) records data obtained by the fiber Bragg grating temperature and stress integrated monitoring system (3), the multi-gas monitoring system (4), and the image and video monitoring system (5).

7. A method for visualizing a similarity simulation test of a coalfield fire evolution process, using the device for visualizing a similarity simulation test of a coalfield fire evolution process according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Calculate and design the size and conditions of the physical similarity model (2) of the actual experimental coalfield fire according to the similarity criterion, build a test bench (1) according to the size and conditions of the physical similarity model (2), assemble and fix a plurality of opening frames (12) in sequence, and insert a heat-insulating glass (13) on the outermost opening frame (12) to form a test box, arrange the physical similarity model (2) in the test box, and use the inclination adjustment mechanism (14) to adjust the test box to a set inclination angle; S2, placing the fiber Bragg grating temperature and stress integrated monitoring system (3) in the physical similarity model (2) to perform temperature and stress monitoring; S3, after the physical similarity model (2) is allowed to air dry and solidify, the fiber Bragg grating temperature and stress integrated monitoring system (3), the multi-gas monitoring system (4) and the image and video monitoring system (5) are respectively connected to the computer analysis system (6); S4, supplying gas to the physical similarity model (2) through the gas supply system (15), and opening the ignition system (16) to ignite the physical similarity model (2), and conducting a similar simulation test of the coalfield fire evolution process. At this time, the fiber Bragg grating temperature and stress integrated monitoring system (3) and the image and video monitoring system (5) are started to monitor data. When the coalfield fire area in the test box collapses and cracks are generated, the detection head of the multi-gas monitor of the multi-gas monitoring system (4) is inserted into the crack to monitor the gas concentration value; S5. After the combustion of the physical similarity model (2) is completed, the test box is allowed to stand and cool naturally to room temperature. Insulation glass (13) is inserted into the slots on both sides of each opening frame (12). The physical similarity model (2) after combustion is sliced. The multiple opening frames (12) assembled are disassembled. The image and video monitoring system (5) is used to record the two-dimensional slice image of each opening frame (12) after sliding out. The two-dimensional slice image data set is obtained and the two-dimensional slice image data set is transmitted to the computer analysis system (6). The computer analysis system (6) uses Matlab to reconstruct the three-dimensional crack model of the two-dimensional slice image data set. ParaView is used to render and analyze the spatiotemporal distribution data measured by each system to construct a dynamic visualization model of multi-physical field coupling.

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