High-degree-of-freedom gas-dust explosion fidelity simulation device and experiment method

Abstract

The invention provides a high-degree-of-freedom gas-dust explosion fidelity simulation device and an experiment method. The high-degree-of-freedom gas-dust explosion fidelity simulation device comprises an experiment pipeline system, a ventilation system, a gas configuration system, a remote control ignition device, a roadway equipment model and a data analysis system. The pipeline system is formed by connecting pipeline sections of different structures, explosion venting pipelines and flange plates. The ventilation system and gas configuration system is composed of a small fan, a reduced-size automatic air door, an electromagnetic valve, an air compressor, a dust ejector, an intelligent pressure transmitter, a gas cylinder A and the like. The gas distribution system comprises a vacuum pump, an intelligent pressure transmitter, an air compressor, a gas storage tank and a gas cylinder. The remote control ignition device is formed by refitting an original small remote control car, a car body shell is an anti-explosion shell, an ignition electrode is additionally arranged on a car roof, and a direct-current stabilized power supply for supplying energy to the ignition electrode is installed in the car body. The roadway equipment model is a 1: 35 reduced-size conveyor belt model, a reduced-size coal mining machine model, a reduced-size heading machine model and a reduced-size hydraulic support model which are prepared through 3D printing. The data analysis system comprises a high-speed camera, a multi-parameter gas sensor, an overpressure sensor, a schlieren instrument and the like. According to the invention, the experiment research of the whole process of gas and dust diffusion-explosion based on the tunnel ventilation network is supported, the real scene of the mine explosion accident is effectively restored, the disaster source identification early warning and targeted prevention of the explosive gas are expected to be realized, and the explosion accident is prevented and controlled from the source.

Description

Technical Field

[0001] The present invention relates to the field of mine disaster prevention and control, and in particular to a high-freedom gas-dust explosion fidelity simulation device and an experimental method. Technical Background

[0002] Coal is my country's primary energy source. As shallow coal resources have been nearly depleted, coal mining depths are increasing annually, with mining at depths exceeding 1,000 meters becoming the norm. Mining deep coal seams is associated with high stress concentrations, high gas concentrations, and thermal hazards, making mine accidents more complex and more hazardous.

[0003] Among all coal mine accidents, gas-dust explosions are the most serious dynamic hazards. The shock waves generated by the rapid expansion of combustible gases within the semi-enclosed space of a coal mine working face pose a serious threat to the safety of underground workers, damage equipment such as shearers, and cause violent vibrations in the tunnel walls within a short period of time, severely impacting emergency rescue and production recovery after the accident. In addition to the highly destructive shock waves, the tunnel ventilation network conditions, the complex spatial structure of underground tunnels, and the presence of obstacles within the coal tunnels increase the complexity of gas explosion accidents, making breakthrough research difficult.

[0004] Existing experimental studies of mine gas-dust explosions often pre-fill a specific section of the explosion duct with a defined concentration and volume of premixed gas-air, or uniformly inject coal dust into it before the experiment begins. A thin membrane isolates the explosive gas / dust from the rest of the duct, followed by detonation using a fixed ignition electrode. Based on this, the tunnel structure is modified and various obstacles are placed to study the turbulent flame flow field, shock wave propagation behavior, and the positive feedback between the flame and shock wave. However, in actual mine gas-dust explosion scenarios, the gas-air mixture and dust often fail to achieve a consistent premixed concentration and uniform distribution within a specific area, influenced by ventilation conditions, tunnel structure, and mine equipment. Furthermore, when the mine ventilation system malfunctions, gas or dust often concentrates in a poorly ventilated tunnel space, with some dust depositing on the tunnel floor rather than being evenly distributed. It is necessary to investigate the effects of ventilation system failure, partial failure, and normal conditions on the diffusion and deflagration of explosive gas and dust within complex tunnel networks with obstacles. Therefore, the applicant proposed a high-degree-of-freedom gas-dust explosion fidelity simulation device and experimental method to further restore the real scene of the mine explosion accident, and carry out experimental research on the entire process of gas and dust diffusion-explosion based on the tunnel ventilation network, in order to realize the disaster source identification and early warning of explosive gas and targeted prevention, prevent the occurrence of explosion accidents from the root, and ensure the safe production of coal mines. Summary of the Invention

[0005] In response to the above-mentioned defects, the purpose of the present invention is to provide a high-degree-of-freedom gas-dust explosion fidelity simulation device and experimental method. The experimental device adopts a variety of structural tunnels including straight tunnels, forks, inclined tunnels, etc. and an adjustable ventilation network to improve the degree of freedom and functionality of the experimental device. It can conduct experimental research on the entire process of gas-dust diffusion to explosion under normal or faulty ventilation conditions, and solve the problems of previous mine explosion research methods being single, the system being imperfect, and the large difference between the mine explosion scenes under real tunnel ventilation conditions.

[0006] To solve the above problems, the high-degree-of-freedom gas-dust explosion fidelity simulation device consists of five parts: experimental pipeline system, ventilation system and gas configuration system, remote control ignition device, tunnel equipment model, and data analysis system.

[0007] The experimental piping system, the main component of the experimental setup, consists of seven different pipe sections connected to the explosion relief pipe via bolted flanges. The pipes are constructed of steel with a wall thickness of at least 0.03m, a maximum length of over 120m, and a rectangular cross-section measuring 0.8 x 0.8m. The compressive strength exceeds 26MPa, ensuring that the high-intensity shockwave from a gas-coal dust explosion propagates and attenuates within the pipe, preventing the escape of combustible gases and post-explosion exhaust.

[0008] Furthermore, the seven different pipe segments include straight pipes, L-shaped pipes, T-shaped pipes, inclined pipes, 30° bifurcated pipes, 60° bifurcated pipes, and 120° bifurcated pipes. The long sides of the straight pipes, inclined pipes, and T-shaped pipes, as well as the length of each branch of the bifurcated pipes, are 6 meters long. The short sides of the L-shaped pipes and the short sides of the T-shaped pipes are 3 meters long. Each pipe segment can be fitted with a flange, ensuring stable connections between pipe segments to form a complex spatial network. Polyethylene film can be placed inside the pipes to isolate combustible gases or dust before the experiment begins.

[0009] The ventilation system and gas configuration system include a small fan, a reduced-size automatic damper, an electromagnetic valve, an air compressor, a dust ejector, an intelligent pressure transmitter, a gas cylinder, a vacuum pump, a gas premix tank, and an air cylinder.

[0010] Furthermore, the small fan and the reduced-size automatic damper as ventilation facilities of the entire experimental system can realize one-button start and stop, and real-time adjustment of the fan air volume and damper opening through remote control. The small fan is installed near the port of the experimental pipeline, with a blade diameter of 450mm and a maximum output air volume of 0.80m 3 / sm 3 Multiple reduced-size automated dampers can be simultaneously placed at different locations in the piping system, and closing them can completely block the laneway.

[0011] Furthermore, the air compressor, dust ejector, intelligent pressure transmitter, and gas cylinder are interconnected via solenoid valves to form a combustible gas-dust configuration system, used to inject a predetermined concentration of combustible gas and dust into the pipeline system. Furthermore, the air compressor, gas premix tank, gas cylinder, air bottle, and vacuum pump are interconnected via solenoid valves to form a gas-air premix system, which can inject a premixed gas-air mixture of the target concentration into the pipeline.

[0012] The remote-controlled ignition device is based on an explosion-proof remote-controlled vehicle that can be remotely operated. Based on an existing small remote-controlled vehicle, it features an internal DC regulated power supply, an external explosion-proof housing made of fiber-reinforced composite materials, and an ignition electrode mounted on the roof. To ignite combustible gas / dust, the remote-controlled vehicle is remotely driven to a designated location, and the ignition electrode is activated to detonate the combustible gas / dust.

[0013] The tunnel equipment models are 1:35 scale models of four common mining equipment: a roadheader, shearer, conveyor belt, and hydraulic support. These are produced using 3D printing, using high-hardness, high-temperature-resistant ceramic as the base material. One or two each of the roadheader, shearer, and conveyor belt are required, and at least 20 hydraulic support models are needed to serve as obstacles in the experimental pipeline.

[0014] The data analysis system includes a high-speed camera, a multi-parameter gas sensor, a dust concentration sensor, an overpressure sensor, a temperature sensor, a Schlieren instrument, and a control host. The high-speed camera is used to capture high-definition images of the turbulent explosion flame as it migrates through the tunnel and flows around obstacles. The multi-parameter gas sensor is used to monitor the gas concentration at different locations within the pipeline after gas is injected into the pipeline. It can also be used to measure the concentration of explosion product gases such as CO and CO2 after the explosion. The dust concentration sensor is used to monitor the concentration of dust at different locations before ignition due to the influence of the pipeline ventilation system. The overpressure sensor can be used to accurately monitor the temporal changes in the shock wave overpressure at different locations within the pipeline. The temperature sensor is used to measure changes in the explosion flame temperature. The Schlieren instrument is primarily used to observe the migration behavior of dust before and after ignition. The data collected by each data acquisition device is transmitted to the control host for analysis and processing.

[0015] Furthermore, the high-speed camera has ultra-high-speed capture, processing and analysis capabilities, with a maximum frame rate of 500,000 fps. The shutter adopts a global shutter with a processing capacity of 8.3 GP / s, and can capture the moment of change of the explosion turbulent flame in microsecond time units.

[0016] Furthermore, the multi-parameter gas sensor has a monitoring range of 0-1000ppm, a monitoring error of less than 5%, a response time of less than 30 seconds, and a measurement accuracy of 0.1ppm. The dust concentration sensor can be customized to the actual conditions of the mine, with an error of less than 0.1% and a response time of less than 20 seconds.

[0017] Furthermore, the overpressure sensor monitors the shock wave overpressure generated by gas and coal dust explosions, with a sensitivity of 0.1ms and an overpressure monitoring range of -0.06-3MPa.

[0018] Furthermore, the temperature sensor has a measuring range of 3m and a measuring temperature range of 0-1350°C.

[0019] The present invention also provides a high-degree-of-freedom gas-dust explosion fidelity simulation experimental scheme, the steps of which are as follows:

[0020] a. Preparation Phase: A series of preparatory steps are required before the experiment begins. First, develop an experimental plan, draw a diagram of the experimental pipeline structure based on the specific experimental requirements, and prepare to assemble the experimental pipeline sections for the required pipeline structure. The pipeline structure diagram should indicate the locations of each ventilation structure and tunnel equipment model. Based on the ventilation structure and obstruction types, the experimental pipeline should be classified as a mining tunnel, an air supply / return tunnel, and a connecting tunnel. The locations of each monitoring point should also be clearly marked on the diagram. Then, a 1:35 scale model of the tunnel equipment is produced using 3D printing. According to the drawings, the tunnel equipment models, small fans, and scaled-down automated dampers are arranged within the experimental pipeline sections. The ventilation equipment is checked for proper operation, and the fan air volume output and damper opening accuracy meet the requirements. Various sensors are installed within the experimental pipeline sections according to the drawings. A high-speed camera and Schlieren instrument are placed outside the pipeline. The data acquisition system is checked for proper operation to ensure that all equipment, especially the pressure sensor, high-speed camera, and Schlieren instrument, are functioning properly at the start of the experiment. Next, each tunnel section is connected with flanges according to the drawings to form the required experimental pipeline structure. After the pipeline is connected, the air tightness of the entire pipeline is strictly checked using an intelligent pressure transmitter.

[0021] b. Gas Distribution Phase: Based on the previously prepared experimental plan, determine whether the subsequent experiment will be a combustible gas / dust diffusion-explosion test or a traditional premixed gas explosion test. The combustible gas / dust diffusion-explosion test requires a combustible gas-dust distribution system consisting of an air compressor, dust ejector, intelligent pressure transmitter, gas cylinder, and solenoid valve. This test does not require a pre-established gas-air mixture concentration. However, before introducing gas / dust into the piping system, ventilation conditions must be prepared for the test ducts. The output air volume of the small blower and the opening and closing of the reduced-size automated damper must be determined. For traditional premixed gas explosion tests, a detonation duct and a transmission duct should be separated by a 0.025mm thick polyethylene film. A vacuum pump, gas cylinder, air cylinder, gas premix tank, air compressor, and solenoid valve are connected to form the gas-air premix system. The vacuum pump extracts the gas from the detonation duct, and the value displayed by the intelligent pressure transmitter confirms the vacuum in the detonation duct. Then, the solenoid valves of the gas cylinder and the air cylinder are opened, the two gases are charged into the gas premix tank, and the gas-air premix gas is prepared in a certain ratio.

[0022] c. Ignition and Data Analysis: After the experimental duct ventilation system and combustible gas / dust are prepared, a predetermined volume or mass of combustible gas / dust is introduced into the experimental duct. After maintaining the duct ventilation conditions for a period of time, the remote-controlled vehicle is piloted to the location within the duct system where the multi-parameter gas concentration sensor or dust concentration sensor indicates the highest gas / dust concentration. The ignition electrode is then activated to ignite the gas / dust. Simultaneously, overpressure sensors, temperature sensors, a high-speed camera, and a schlieren device are activated to obtain an explosion overpressure-time curve, high-definition images of flame propagation, a flame temperature-time curve, and the trajectory of the entrained coal dust.

[0023] d. Cleaning of experimental pipelines: After the experiment, turn off the small fan and all data acquisition equipment, connect the pipeline and the air compressor, and flush fresh air into the pipeline so that the residual gas in the pipeline is discharged into the explosion venting pipeline.

[0024] e. Control Experiment: After the experimental pipeline is cleaned, a conventional premixed gas explosion experiment can be conducted as a control. This experiment should use the same volume or mass of gas / dust as the previous experiment and fully premix it with air. After the mixed gas / dust is prepared, the detonation pipeline is located around the detonation point of the previous experiment and polyester film is placed. The detonation pipeline is evacuated using a vacuum pump and then filled with the premixed gas / dust. It is then ignited for control experimental analysis.

[0025] Compared with other mine gas explosion test devices, the present invention has the following advantages:

[0026] The development of this device is closely centered around the core feature of "high degree of freedom", which is mainly reflected in the high degree of freedom of the experimental pipeline structure, the high degree of freedom of the ventilation network system, and the high degree of freedom of the ignition device. The experimental pipeline includes seven different structural pipeline sections: straight pipeline (1), L-shaped pipeline (2), T-shaped pipeline (3), inclined pipeline (4), 30° bifurcated pipeline (5), 60° bifurcated pipeline (6), and 120° bifurcated pipeline (7). The pipeline sections can be assembled through the flanges at the ports to form a complex pipeline network required for the experiment. At the same time, four typical tunnel equipment models can be arranged inside the pipeline as obstacles to simulate the mining space; before the experiment, the output air volume of the small fan and the opening and closing of the reduced-size automatic damper can be set to simulate the normal ventilation system or any abnormal ventilation system conditions including insufficient fan power, damper failure, etc., so that gas / dust can diffuse in the pipeline system under different ventilation conditions; under the influence of ventilation system abnormalities and obstacles, the gas / dust concentration in some local areas of the experimental pipeline may exceed the explosion threshold. By using an ignition device based on a remote-controlled vehicle, the fire source position is not fixed but can move freely in the experimental pipeline and ignite gas / dust as needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a layout diagram of the ventilation structure and monitoring points in the example experimental pipeline of the high-degree-of-freedom gas-dust explosion fidelity simulation experimental device.

[0028] Figure 2 It is a schematic diagram of seven different pipeline sections, including straight lanes, L-shaped lanes, and T-shaped lanes.

[0029] Figure 3 Remote control ignition device, tunnel equipment model, and data analysis system diagram

[0030] In the figure: 1 - straight pipe, 2 - L-shaped pipe, 3 - T-shaped pipe, 4 - inclined pipe, 5 - 30° bifurcated pipe, 6 - 60° bifurcated pipe, 7 - 120° bifurcated pipe, 8 - flange, 9 - explosion relief pipe, 10 - small fan, 11 - reduced-size automatic damper, 12 - monitoring point, 13 - solenoid valve A, 14 - solenoid valve B, 15 - solenoid valve C, 16 - solenoid valve D, 17 - solenoid valve E, 18 - air compressor A, 19 - dust ejector, 20 - intelligent pressure transmitter A, 21 - gas cylinder A, 22 - polyethylene film, 23 - solenoid valve F, 24 - solenoid valve G, 25 - solenoid valve H, 26 - solenoid valve I, 27—Solenoid valve J, 28—Solenoid valve K, 29—Solenoid valve L, 30—Air compressor B, 31—Vacuum pump, 32—Intelligent pressure transmitter B, 33—Gas premix tank, 34—Gas cylinder, 35—Air cylinder, 36—High-speed camera, 37—Multi-parameter gas concentration sensor, 38—Dust concentration sensor, 39—Overpressure sensor, 40—Temperature sensor, 41—Schlieren instrument, 42—Conveyor belt scale model, 43—Coal mining machine scale model, 44—Tunneling machine scale model, 45—Hydraulic support scale model, 46—Control host, 47—Ignition electrode, 48—Remote control vehicle body, 49—Explosion-proof housing, 50—DC regulated power supply. DETAILED DESCRIPTION

[0031] In order to clearly illustrate the overall structure and technical process of the present invention, the inventive device is further described in detail with reference to the drawings in the specification. The specific examples described are only used to explain the present invention and are not used to limit the present invention.

[0032] As attached Figure 1 , Attachment Figure 2 and attached Figure 3 As shown, the present invention provides a high-degree-of-freedom gas-dust explosion fidelity simulation experimental device comprising five parts: an experimental piping system, a ventilation system and a gas configuration system, a remote control ignition device, a tunnel equipment model, and a data analysis system.

[0033] The experimental piping system is the core of the entire experimental device. It is a steel pipe with a wall thickness of at least 0.03m and a rectangular cross-section of 0.8×0.8m. Its compressive strength exceeds 26MPa. It is composed of seven different pipe sections (1-7) with different structures, an explosion relief pipe (9), and a flange (8) fixed by bolts. Its maximum length can reach 120m. The experimental pipe can withstand the pressure load of a 9.5% concentration gas-air mixture and a gas-dust explosion. The seven different pipe sections (1-7) with different structures are tightly connected to the explosion relief pipe and flange to ensure that combustible gas and exhaust gas after the explosion cannot leak from the pipe.

[0034] Furthermore, the seven different structural pipeline sections are straight pipeline (1), L-shaped pipeline (2), T-shaped pipeline (3), inclined pipeline (4), 30° bifurcated pipeline (5), 60° bifurcated pipeline (6), and 120° bifurcated pipeline (7). The length of the long sides of the straight pipeline (1), inclined pipeline (4), and T-shaped pipeline (3) and the bifurcated lengths of the 30° bifurcated pipeline (5), 60° bifurcated pipeline (6), and 120° bifurcated pipeline (7) is 6 meters, and the length of the two sides of the L-shaped pipeline (2) and the short side of the T-shaped pipeline (3) is 3 meters. A flange can be installed at the port of each pipeline section, so that the pipeline sections are stably connected to form a complex pipeline space network.

[0035] The ventilation system and gas configuration system are composed of a small fan (11), a reduced-size automatic damper (12), electromagnetic valves AL (13, 14, 15, 16, 17, 23, 24, 25, 26, 27, 28, 29), an air compressor A (18) and an air compressor B (30), a dust ejector (19), an intelligent pressure transmitter A (20) and an intelligent pressure transmitter A (32), a gas cylinder A (21) and a gas cylinder B (34), a vacuum pump (31), a gas premixing tank (33), and an air cylinder (35).

[0036] Furthermore, the ventilation system in the experimental pipeline mainly includes two ventilation structures, a small fan (11) and a reduced-size automatic damper (12), which can be installed at any position in the experimental pipeline according to actual experimental requirements. Before the gas / dust is detonated, the small fan (11) and the reduced-size automatic damper (12) can be remotely controlled by the control host (46) to achieve one-button start and stop, and real-time adjustment of the fan air volume and damper opening. The diameter of the small fan blade is 450mm, and the output air volume can reach 0.80m 3 / sm 3 The reduced-size automatic damper (12) is a small steel explosion-proof automatic door customized according to the size of the experimental pipeline. Wind flow and combustible gas cannot pass through the completely closed reduced-size automatic damper (12).

[0037] Furthermore, the gas configuration system has two modes. The first is a combustible gas-dust configuration system, which is composed of an air compressor A (18), a dust ejector (19), an intelligent pressure transmitter A (20), and a gas cylinder A (21) connected by electromagnetic valves AE (13, 14, 15, 16, 17), and is used to fill a certain volume or mass of gas / dust into an experimental pipeline equipped with a ventilation system without the need to pre-configure a certain concentration of methane-air premixed gas. The other is a traditional gas-air premixing system, which is composed of an air compressor B (30), a vacuum pump (31), an intelligent pressure transmitter B (32), a gas premixing tank (33), a gas cylinder B (34), and an air cylinder (35) connected by electromagnetic valves FL (23, 24, 25, 26, 27, 28, 29), and is mainly used to configure a target concentration of gas-air premixed gas before the start of the experiment.

[0038] The remote control ignition device includes a control host (46), an ignition electrode (47), a remote control vehicle body (48), an explosion-proof housing (49), and a DC regulated power supply (50). The device is modified based on an original small remote control vehicle. The vehicle body shell uses an explosion-proof housing (49) made of fiber-reinforced composite material, which is sufficient to ensure that the vehicle body at the center of the explosion is not severely damaged. An ignition electrode (47) is installed on the roof of the remote control vehicle, and a DC regulated power supply (50) for supplying energy to the ignition electrode (47) is installed inside. When it is necessary to ignite gas / dust, the remote control vehicle is remotely controlled by the control host (46) to travel to a predetermined position and turn on the ignition electrode (47) to perform ignition.

[0039] The tunnel equipment models are four types: a scaled-down conveyor belt model (42), a scaled-down coal mining machine model (43), a scaled-down roadheader model (44), and a scaled-down hydraulic support model (45). These four 1:35 scaled-down models of the most common equipment on the mining face are based on the STL three-dimensional models of the roadheader, coal mining machine, conveyor belt, and hydraulic support, and are made by 3D printing using high-hardness and high-temperature resistant ceramic as the base material. Among them, 1 to 2 scaled-down conveyor belt models (42), scaled-down coal mining machine models (43), and scaled roadheader models (44) are required, and more than 20 hydraulic support models are required to be made to be placed in the experimental pipeline as obstacles.

[0040] The data analysis system includes a high-speed camera (36), a multi-parameter gas sensor (37), a dust concentration sensor (38), an overpressure sensor (39), a temperature sensor (40) and a Schlieren instrument (41). The high-speed camera (36) and the Schlieren instrument (41) are arranged outside the experimental pipeline before the experiment, respectively used to capture high-definition images of the explosion turbulent flame moving in the tunnel and observe the migration behavior of dust before and after ignition. The multi-parameter gas sensor (37), the dust concentration sensor (38), the overpressure sensor (39) and the temperature sensor (40) are arranged at the monitoring point (12) in the experimental pipeline, respectively used to monitor the concentration of gas, CO, CO2 and dust at different positions in the experimental pipeline and the change process of shock wave overpressure and flame temperature at different positions in the pipeline over time.

[0041] The present invention also provides a high-degree-of-freedom gas-dust explosion fidelity simulation experimental scheme, the steps of which are as follows:

[0042] a. Experimental design: Based on the research needs and the spatial characteristics of the mine tunnel, ventilation facility parameters, on-site ventilation structures, and the distribution of tunnel equipment, a design diagram of the experimental pipeline structure is drawn. In addition to the experimental pipeline structure, the design diagram also includes the layout of the ventilation facilities and four tunnel equipment models, and the location information of the monitoring points (12). Subsequently, based on the ventilation structures and obstacle types, the experimental pipeline is defined as a mining tunnel, an air intake / return air tunnel, and a connecting tunnel. The initial ventilation conditions in the experimental pipeline, the volume or mass of gas / dust entering the experimental pipeline, and the installation locations of the external high-speed camera (36) and the schlieren (41) are determined, and a detailed experimental plan is formulated.

[0043] b. Preparation of tunnel equipment models: Simplified geometric models of four tunnel equipment were created through 3D modeling, omitting tiny components such as screws, buttons, and gears. These models were then imported into a 3D printer in STL format. Subsequently, ceramic materials were prepared for 3D printing, and scaled-down models of a shearer (43), a roadheader (44), and a hydraulic support (45) were produced, each at a 1:35 ratio to the actual tunnel equipment.

[0044] c. Preparation before the experiment: Arrange four types of tunnel equipment models, small fans (10), and reduced-size automatic dampers (11) in the experimental pipeline section according to the drawings. Check whether the ventilation facilities can operate normally and whether the fan air volume output and damper opening accuracy meet the requirements. At the same time, install various sensors according to the monitoring points (12) marked on the drawings, arrange high-speed cameras and Schlieren instruments on the outside of the pipeline, check whether the data acquisition system is in normal condition, and ensure that all equipment, especially pressure sensors, high-speed cameras and Schlieren instruments, can operate normally at the beginning of the experiment. After that, connect each tunnel section to each other through flanges according to the drawings to form the required experimental pipeline structure. After the pipeline is connected, strictly check the air tightness of the entire pipeline through the intelligent pressure transmitter.

[0045] d. Ventilation system setup: Based on the experimental plan developed in the previous steps, adjust the output air volume of the small fan (10) and the opening of the reduced-size automatic damper (11) to simulate normal ventilation and different types of faults that cause ventilation system abnormalities. For example, to simulate a mechanical failure of the fan, the output air volume of the small fan (10) can be significantly reduced before the experiment. To simulate a damper abnormality, the reduced-size automatic damper (11) needs to be continuously closed in advance. After the ventilation system is set up, start the air distribution system to deliver the set amount of gas / dust into the experimental pipeline.

[0046] e. Gas distribution preparation: When conducting a gas diffusion-explosion experiment, open the electromagnetic valve A (13), electromagnetic valve D (16) and electromagnetic valve E (17), open the gas cylinder A (21) and send the gas into the experimental pipeline. During this process, the volume of the gas introduced is confirmed by reading the intelligent pressure transmitter A (20). After reaching the predetermined value, the gas cylinder A (21) and the electromagnetic valve A (13), electromagnetic valve D (16) and electromagnetic valve E (17) are closed, and the gas introduction is stopped and the gas in the pipeline is affected by the ventilation system to diffuse. When conducting a dust diffusion-explosion experiment, open the electromagnetic valve A (13) and electromagnetic valve C (15), open the dust ejector (19) and pay attention to its surface reading. After the predetermined mass of dust is introduced into the experimental pipeline, close the electromagnetic valve A (13), electromagnetic valve C (15) and dust ejector (19) and stop introducing dust. When conducting a traditional premixed gas explosion experiment, a detonation pipe and a transmission pipe should be selected, and the detonation pipe and the transmission pipe should be separated by a polyethylene film (22) with a thickness of 0.025 mm. Open the electromagnetic valve F (23), electromagnetic valve H (25) and electromagnetic valve I (26), start the vacuum pump (31) to extract the gas in the detonation pipe, and confirm whether the detonation pipe is in a vacuum state according to the value displayed by the intelligent pressure transmitter (32). Subsequently, close the electromagnetic valve H (25) and the vacuum pump (31), open the electromagnetic valve J (27), electromagnetic valve K (28), and electromagnetic valve L (29), open the gas cylinder B (34) and the air cylinder (35), and fill the two gases into the gas premix tank (33). A gas-air premix gas of a certain concentration is prepared by the partial pressure method.

[0047] f. Ignition: After the gas / dust is fed into the experimental pipeline, the pipeline ventilation condition is maintained for a certain period of time, and the remote control vehicle (48) is controlled by the control host (46) to travel to the position where the multi-parameter gas concentration sensor (37) or the dust concentration sensor (38) in the pipeline system shows the highest gas / dust concentration value, and the ignition electrode (37) is activated to ignite the gas / dust.

[0048] g. Data analysis. At the moment of ignition, the high-speed camera (36), multi-parameter gas concentration sensor (37), dust concentration sensor (38), overpressure sensor (39), temperature sensor (40), and schlieren (41) are all fully operational at the same time to obtain high-definition images of flame propagation, gas / dust explosion overpressure-time curves, gas / dust / explosion product concentration-instantaneous curves, flame temperature-time curves, and the trajectory of the entrained coal dust. These data are transmitted to the control host for unified analysis.

[0049] h. Cleaning the experimental pipeline. After the experiment is completed, turn off all small fans (10) and data acquisition equipment in the experimental pipeline, open the electromagnetic valve A (13) and electromagnetic valve B (14) and start the air compressor A (18), or open the electromagnetic valve B (23) and electromagnetic valve G (24) and start the air compressor B (30), and send fresh air into the experimental pipeline. At the same time, adjust the opening and closing of the automatic damper (11) in the pipeline until the residual gas in the pipeline is discharged into the explosion venting pipeline (9).

Claims

1. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device consists of five parts: experimental pipeline system, ventilation system and gas configuration system, remote control ignition device, tunnel equipment model, and data analysis system.

2. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device according to claim 1 is characterized in that: The experimental pipeline system is the core part of the entire experimental device. It is a steel pipeline with a rectangular cross-section and a compressive strength of more than 26MPa. It is composed of seven different structural pipeline sections (1-7), explosion-proof pipelines (9) and flanges (8) fixed by bolts. Its maximum length can reach more than 120m. The experimental pipeline can withstand the pressure load of 9.5% concentration gas-air mixture and gas-dust explosion, and the seven different structural pipeline sections (1-7) are tightly connected with the explosion-proof pipeline and flanges to ensure that combustible gas and exhaust gas after explosion cannot leak from the pipeline. The seven different structural pipeline sections (1-7) are connected with the explosion-proof pipeline and flanges to ensure that combustible gas and exhaust gas after explosion cannot leak from the pipeline. The pipeline sections are straight pipeline (1), L-shaped pipeline (2), T-shaped pipeline (3), inclined pipeline (4), 30° bifurcated pipeline (5), 60° bifurcated pipeline (6), and 120° bifurcated pipeline (7); the length of the long sides of the straight pipeline (1), inclined pipeline (4), and T-shaped pipeline (3) and the length of each bifurcation of the 30° bifurcated pipeline (5), 60° bifurcated pipeline (6), and 120° bifurcated pipeline (7) is 6 meters, and the length of both sides of the L-shaped pipeline (2) and the short side of the T-shaped pipeline (3) is 3 meters. A flange can be installed at the port of each pipeline section to ensure stable connection between the pipeline sections to form a complex pipeline space network.

3. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device according to claim 1 is characterized by: The ventilation system and gas configuration system are composed of a small fan (11), a reduced-size automatic damper (12), electromagnetic valves AL (13, 14, 15, 16, 17, 23, 24, 25, 26, 27, 28, 29), an air compressor A (18) and an air compressor B (30), a dust ejector (19), an intelligent pressure transmitter A (20) and an intelligent pressure transmitter A (32), a gas cylinder A (21) and a gas cylinder B (34), a vacuum pump (31), a gas premixing tank (33), and an air cylinder (35).

4. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device according to claim 1 is characterized in that: The ventilation system in the experimental pipeline mainly includes two ventilation structures, a small fan (11) and a reduced-size automatic damper (12), which can be installed at any position in the experimental pipeline according to actual experimental requirements; before the gas / dust is detonated, the small fan (11) and the reduced-size automatic damper (12) can be remotely controlled by a control host (46) to achieve one-button start and stop, and real-time adjustment of the fan air volume and damper opening; the reduced-size automatic damper (12) is a small steel explosion-proof automatic door customized according to the size of the experimental pipeline, and airflow and combustible gas cannot pass through the completely closed reduced-size automatic damper (12).

5. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device according to claim 1 is characterized in that: The gas configuration system has two modes; the first is a combustible gas-dust configuration system, which is composed of an air compressor A (18), a dust ejector (19), an intelligent pressure transmitter A (20), and a gas cylinder A (21) connected by electromagnetic valves AE (13, 14, 15, 16, 17), and is used to fill a determined volume or mass of gas / dust into an experimental pipeline equipped with a ventilation system without the need to configure a certain concentration of methane-air premixed gas in advance; the other is a traditional gas-air premixing system, which is composed of an air compressor B (30), a vacuum pump (31), an intelligent pressure transmitter B (32), a gas premixing tank (33), a gas cylinder B (34), and an air cylinder (35) connected by electromagnetic valves FL (23, 24, 25, 26, 27, 28, 29), and is mainly used to configure a target concentration of gas-air premixed gas before the start of the experiment.

6. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device according to claim 1 is characterized in that: The remote control ignition device comprises a control host (46), an ignition electrode (47), a remote control car body (48), an explosion-proof shell (49) and a DC regulated power supply (50); the device is modified based on an original small remote control car, and the car body shell uses an explosion-proof shell (49) made of fiber-reinforced composite material, which is sufficient to ensure that the car body at the center of the explosion is not seriously damaged; an ignition electrode (47) is installed on the roof of the remote control car, and a DC regulated power supply (50) for supplying energy to the ignition electrode (47) is installed inside; when it is necessary to ignite gas / dust, the remote control car is remotely controlled by the control host (46) to travel to a predetermined position and turn on the ignition electrode (47) to perform ignition.

7. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device according to claim 1 is characterized by: The tunnel equipment models are four types: a reduced-size conveyor belt model (42), a reduced-size coal mining machine model (43), a reduced-size roadheader model (44), and a reduced-size hydraulic support model (45); the 1:35 reduced-size models of the four most common equipment on the mining face are based on the STL three-dimensional models of the roadheader, coal mining machine, conveyor belt and hydraulic support, and are made of high-hardness and high-temperature resistant ceramics as the basic material and are made by 3D printing; among them, 1 to 2 reduced-size conveyor belt models (42), reduced-size coal mining machine models (43), and reduced-size roadheader models (44) are required to be prepared, and more than 20 hydraulic support models are required to be prepared to be placed in the experimental pipeline as obstacles.

8. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental device according to claim 1 is characterized by: The data analysis system includes a high-speed camera (36), a multi-parameter gas sensor (37), a dust concentration sensor (38), an overpressure sensor (39), a temperature sensor (40) and a schlieren instrument (41); wherein the high-speed camera (36) and the schlieren instrument (41) are arranged outside the experimental pipeline before the experiment, and are respectively used to take high-definition images of the explosion turbulent flame moving in the tunnel and observe the migration behavior of dust before and after ignition; the multi-parameter gas sensor (37), the dust concentration sensor (38), the overpressure sensor (39) and the temperature sensor (40) are arranged at the monitoring point (12) in the experimental pipeline, and are respectively used to monitor the concentration of gas, CO, CO2 and dust at different positions in the experimental pipeline and the change process of shock wave overpressure and flame temperature at different positions in the pipeline over time.

9. The high-degree-of-freedom gas-dust explosion fidelity simulation experimental scheme according to any one of claims 1 to 6, characterized in that: The following steps are involved: a. Experimental design: Based on the spatial characteristics of the mine tunnel, ventilation facility parameters, on-site ventilation structures, and the distribution of tunnel equipment, a design diagram of the experimental pipeline structure is drawn. In addition to the experimental pipeline structure, the design diagram also includes the layout of the ventilation facilities and four tunnel equipment models, and the location information of the monitoring points (12). Subsequently, based on the ventilation structures and obstacle types, the experimental pipeline is defined as a mining tunnel, an air supply / return tunnel, or a connecting tunnel. The initial ventilation conditions in the experimental pipeline, the volume or mass of gas / dust introduced into the experimental pipeline, and the installation locations of the external high-speed camera (36) and the schlieren (41) are determined, and a detailed experimental plan is formulated. b. Preparation of tunnel equipment models: Simplified geometric models of four tunnel equipment are created through 3D modeling, ignoring tiny components such as screws, buttons, and gears, and imported into a 3D printing device in STL format. Subsequently, ceramic materials required for 3D printing are prepared to produce a scaled-down coal mining machine model (43), a scaled-down roadheader model (44), and a scaled-down hydraulic support model (45) that are 1:35 scaled to the actual tunnel equipment. c. Preparation before the experiment: Arrange four types of tunnel equipment models, small fans (10), and reduced-size automatic dampers (11) in the experimental pipeline section according to the drawings; check whether the ventilation facilities can operate normally, and whether the fan air volume output and damper opening accuracy meet the requirements; at the same time, install various sensors according to the monitoring points (12) marked on the drawings, arrange high-speed cameras and Schlieren instruments on the outside of the pipeline, check whether the data acquisition system is in normal condition, and ensure that all equipment, especially pressure sensors, high-speed cameras and Schlieren instruments, can operate normally at the beginning of the experiment; after that, connect each tunnel section to each other through flanges according to the drawings to form the required experimental pipeline structure; after the pipeline is connected, strictly check the air tightness of the pipeline as a whole through the intelligent pressure transmitter; d. Ventilation system setup: According to the experimental plan developed in the previous steps, the output air volume of the small fan (10) and the opening of the reduced-size automatic damper (11) are adjusted to simulate normal ventilation and different types of faults causing abnormal ventilation system scenarios. For example, to simulate a mechanical failure of the fan, the output air volume of the small fan (10) can be significantly reduced before the experiment. To simulate a damper abnormality, a reduced-size automatic damper (11) needs to be continuously closed in advance. After the ventilation system is set up, the gas distribution system is started to deliver the gas / dust into the experimental pipeline according to the set amount. e. Gas distribution preparation: When conducting gas diffusion-explosion experiments, open the electromagnetic valve A (13), electromagnetic valve D (16) and electromagnetic valve E (17), open the gas cylinder A (21) and send the gas into the experimental pipeline; during this process, confirm the volume of the gas introduced by reading the intelligent pressure transmitter A (20), and after reaching the predetermined value, close the gas cylinder A (21) and the electromagnetic valve A (13), electromagnetic valve D (16), and electromagnetic valve E (17), stop the gas introduction, and allow the gas in the pipeline to diffuse under the influence of the ventilation system; when conducting dust diffusion-explosion experiments, open the electromagnetic valve A (13) and electromagnetic valve C (15), open the dust ejector (19) and pay attention to its surface reading. After the predetermined mass of dust is introduced into the experimental pipeline, close the electromagnetic valve A (13), electromagnetic valve C (15), and open the dust ejector (19) and pay attention to its surface reading. C (15) and the dust ejector (19), stop introducing dust; when conducting a conventional premixed gas explosion experiment, the detonation pipe and the transmission pipe should be selected, and the detonation pipe and the transmission pipe should be separated by a polyethylene film (22); open the electromagnetic valve F (23), the electromagnetic valve H (25) and the electromagnetic valve I (26), start the vacuum pump (31) to extract the gas in the detonation pipe, and confirm whether the detonation pipe is in a vacuum state according to the value displayed by the intelligent pressure transmitter (32); then, close the electromagnetic valve H (25) and the vacuum pump (31), open the electromagnetic valve J (27), the electromagnetic valve K (28), the electromagnetic valve L (29), open the gas cylinder B (34) and the air cylinder (35), fill the two gases into the gas premix tank (33), and prepare a gas-air premix gas of a certain concentration by the partial pressure method; f. Ignition: After the gas / dust is fed into the experimental pipeline, the pipeline ventilation condition is maintained for a certain period of time, and the remote control vehicle (48) is controlled by the control host (46) to travel to the position where the multi-parameter gas concentration sensor (37) or the dust concentration sensor (38) in the pipeline system shows the highest gas / dust concentration value, and the ignition electrode (37) is activated to ignite the gas / dust; g. Data analysis: At the moment of ignition, the high-speed camera (36), the multi-parameter gas concentration sensor (37), the dust concentration sensor (38), the overpressure sensor (39), the temperature sensor (40) and the schlieren (41) are all fully operational at the same time to obtain high-definition images of flame propagation, gas / dust explosion overpressure-time curves, gas / dust / explosion product concentration-instantaneous curves, flame temperature-time curves and the motion trajectory of the entrained coal dust. These data will be transmitted to the control host for unified analysis; h. Cleaning of experimental pipelines: After the experiment is completed, turn off all small fans (10) and data acquisition equipment in the experimental pipelines, open the electromagnetic valve A (13) and electromagnetic valve B (14) and start the air compressor A (18) or open the electromagnetic valve B (23) and electromagnetic valve G (24) and start the air compressor B (30) to send fresh air into the experimental pipelines, and at the same time adjust the opening and closing of the automatic damper (11) in the pipeline until the residual gas in the pipeline is discharged into the explosion venting pipeline (9).

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