Experimental device and method for simulating continuous explosion in limited space

Abstract

The invention discloses an experimental device and method for simulating continuous explosion in a confined space. The experimental device for simulating continuous explosion in the confined space comprises a confined space model; the main explosion container is arranged in the confined space model, is used for accommodating a first combustible medium and is provided with an exploder; the sub-container is arranged in the main explosion container and is used for accommodating a second combustible medium; wherein the main explosion container is configured to be broken during detonation and can tear the sub-container, so that the second combustible medium is thrown and ignited, and a secondary explosion process caused by initial detonation is simulated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of explosion disaster simulation and public safety engineering, and particularly relates to an experimental device and method for simulating continuous explosion in a confined space. BACKGROUND

[0002] With the continuous development of the transportation network, the risk of vehicle accidents of flammable and explosive goods (such as oil and natural gas) in tunnels is increasingly prominent. The explosion of an oil and gas tanker in a tunnel is a highly destructive disaster, and its process usually manifests as follows: in the early stage, the tank body is broken due to impact, the leaked flammable gas mixes with air to form a premixed gas, an initial detonation occurs, and a high-intensity shock wave is generated; in the later stage, the liquid or solid fuel thrown by the explosion is ignited or burns violently, forming a secondary energy release. This chain reaction of "initial detonation + secondary explosion" seriously threatens the safety of the tunnel.

[0003] Model tests are an important means to study the effects of such disasters. However, existing explosion simulation experimental devices mainly focus on the detonation simulation of single gas-phase fuel, and can only produce a single shock wave effect, making it difficult to simulate the chain explosion process of multiple forms of fuel participating and energy being released in sequence in real accidents, and unable to provide real and effective basis for tunnel blast-resistant design.

[0004] Therefore, it has become a technical problem to be solved by those skilled in the art to provide an experimental device and method that can accurately simulate the whole process of the initial detonation of an oil and gas tanker in a tunnel triggering a secondary explosion and reproduce its real damage effect. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide an experimental device and method for simulating continuous explosion in a confined space, which can better simulate the whole process of the explosion chain reaction and the real damage form to the confined space structure.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: In a first aspect, the present application provides an experimental device for simulating continuous explosion in a confined space, the core of which is a nested container design. The device includes a confined space model, a main explosion container placed in the model, and a sub-container arranged inside the main explosion container. The main explosion container is used to contain a first flammable medium and is provided with an initiator, and the sub-container is used to contain a second flammable medium.

[0007] The nested structure is designed to solve the problem that the prior art cannot simulate the chain explosion process of multiple forms of fuel participation and energy release in sequence. By configuring the main explosion container to rupture and tear the sub-container when initiated, the second combustible medium is scattered and ignited, thereby accurately simulating the complete disaster chain of "initial detonation → secondary explosion" under laboratory conditions.

[0008] In actual work, the main explosion container is placed inside the confined space model, and the initiator is connected to the remote control system through a wire. After triggering the initiation, the first combustible medium detonation produces a high-intensity shock wave and high temperature, causing the main explosion container to rupture and further tear the sub-container, ultimately triggering a secondary explosion. It should be noted that the confined space model in the device can be any closed or semi-closed structure, including but not limited to tunnels, mines, or ship cabins; the shapes of the main explosion container and the sub-container can also be designed as cylindrical, spherical, or other geometric shapes according to experimental needs.

[0009] On this basis, in order to more realistically simulate the explosion disaster in engineering scenarios, the confined space model is specified as a tunnel model, a roadway model, or a pipeline model. This specific design makes the experimental results more targeted and has engineering guidance value. These models are usually prepared according to geometric similarity ratio, using materials such as reinforced concrete, and the internal space accurately simulates the real confined environment. The main explosion container is placed inside the model, and the model has a sealing structure at both ends to ensure that the explosion energy is accumulated and reflected inside. Of course, in other embodiments, the tunnel model can also be replaced by other structures with similar spatial characteristics, such as underground shelters or large industrial containers.

[0010] Further, in order to ensure the safety and accuracy of the fuel filling process, the main explosion container is connected to the external fuel supply system through a sealed interface (such as a flange interface). At the same time, the sub-container is fixed inside the main explosion container through a clamping slot or bracket, and is wrapped with an anti-static sheath. This design effectively solves the two major safety hazards of fuel leakage and static ignition.

[0011] In specific work, the external fuel supply system (including a gas flow meter and a mixer) is connected to the sealed interface of the main explosion container through a pipeline, realizing accurate filling of the first combustible medium. The sub-container is fixed to the bottom or side wall of the main explosion container through a clamping slot or bracket, and is completely wrapped with an anti-static sheath (such as an anti-static bag) to avoid friction with the inner wall of the main explosion container to generate static sparks. In actual application, the sealed interface can be replaced by a quick connector or a threaded interface; the clamping slot can be a ring slot, a guide rail, or other positioning structures; and the anti-static sheath can also use an anti-static coating or wrapping film as an equivalent means.

[0012] Regarding the selection of container materials, the main explosion container is made of hard PVC or other brittle non-metallic materials, and the sub-container is made of borosilicate glass or other brittle materials. This material selection is to ensure that the container can effectively break and tear when the explosion occurs, while avoiding excessive flying of debris to cause experimental distortion. The bursting pressure of brittle materials is lower than the strength limit of the confined space model, which ensures the controllability and repeatability of the experiment.

[0013] During the explosion process, the shock wave generated by the rupture of the main explosion container can effectively act on the sub-container, causing it to tear and fully scatter the second combustible medium. Among them, the main explosion container material can use brittle plastics such as ABS or ceramics, and the sub-container material can choose ordinary glass, quartz glass or brittle polymers.

[0014] In order to improve the functionality of the experimental device, at least one of the sealing cover, adjustable pressure relief valve and explosion-proof observation window is provided on the confined space model. The coordinated work of these accessories effectively solves the problems of sealing, pressure relief and observation during the experiment: the sealing cover ensures that the explosion energy is fully accumulated in the model; the adjustable pressure relief valve prevents overpressure damage to the model; and the explosion-proof observation window provides a visual window for optical recording. In actual arrangement, the sealing cover is usually arranged at one end of the model and is fastened by flange and bolt; the adjustable pressure relief valve is arranged at the top of the model and is pre-set to relieve pressure; and the explosion-proof observation window is embedded in the side wall of the model and uses explosion-proof glass material. In other embodiments, the sealing cover can be designed as a hinged or sliding type; the adjustable pressure relief valve can be mechanically or electronically controlled; and the shape and material of the explosion-proof observation window can also be adjusted according to requirements.

[0015] In order to realize accurate monitoring of the explosion process, a sensor system including at least one of a pressure sensor, a thermocouple, a strain gauge and an acceleration sensor is arranged on the inner wall of the confined space model. This multi-dimensional monitoring design is to comprehensively capture various physical parameters under explosion load and provide complete data support for analyzing structural damage. These sensors are connected to external data acquisition instruments through wires and measure shock wave pressure time history, temperature change, lining strain and structural vibration response, respectively. The sensors are usually arranged at key positions (such as the top, side wall and bottom) of the model inner wall to capture the spatial distribution characteristics of the explosion effect. Among them, the sensor type can be extended to fiber optic sensors, piezoelectric sensors, etc.; the arrangement position and density can also be flexibly adjusted according to specific experimental requirements.

[0016] A transparent or translucent granular layer (such as a layer of quartz sand) was applied to the outer wall of the confined space model. This design cleverly solved the problems of surface reflection interference and excessive heat dissipation during high-speed camera recording. The transparent granular layer allows optical transmission, while its granular structure highlights the propagation trajectory of surface cracks, significantly improving the clarity of damage observation. This granular layer was uniformly adhered to the outer wall of the model using an adhesive, and it also provided some heat insulation during the explosion process, reducing the impact of external heat dissipation on the internal temperature field. In other embodiments, the granular layer material can be replaced with transparent particles such as glass beads, and its particle size and thickness can be adjusted according to optical requirements.

[0017] Regarding fuel selection, the first combustible medium is a premixed gas of combustible gas and air, and the second combustible medium is metal powder or coal powder. This configuration is designed to realistically simulate typical fuel types in oil and gas tanker accidents: the premixed combustible gas simulates a vapor cloud explosion, and the powdered fuel simulates a dust explosion, making the experiment closer to actual disaster scenarios. During operation, the first combustible medium is introduced into the main explosion container through the fuel supply system, generating an initial detonation after detonation; the second combustible medium is ejected after the sub-container tears, forming a dust cloud, which is ignited by high temperatures, resulting in a secondary explosion. The combination of the two media effectively replicates the coupling mechanism of sequential energy release. The first combustible medium can be acetylene, hydrogen, or other combustible gases; the second combustible medium can be replaced with sulfur powder, wood powder, or other combustible powders.

[0018] Secondly, this invention also provides a method for simulating continuous explosions within a confined space, using the aforementioned apparatus, comprising the following steps: first, filling a sub-container with a second flammable medium and fixing it inside a main explosion container; then placing the main explosion container inside a confined space model; next, filling the main explosion container with a first flammable medium; and finally, detonating the first flammable medium to generate an initial detonation that tears apart the main and sub-containers and scatters the second flammable medium, thereby triggering a secondary explosion. This method aims to systematically solve the problem that existing methods cannot simulate the entire process of continuous explosions, ensuring the standardization of experiments and the comparability of data. The steps in the method are executed sequentially to ensure experimental safety and controllability. Key aspects such as fixing the sub-container, sealing and filling the main explosion container, and remote detonation are all specially designed. In other embodiments, the order of some steps can be appropriately adjusted, such as filling the container before placing it; the detonation method can also be replaced by electric spark, laser ignition, or other alternative means.

[0019] Finally, before introducing the first flammable medium, an inert gas (such as nitrogen) is introduced into the main explosion container for purging. Simultaneously, a monitoring system records physical parameters and images during the explosion process to analyze the damage effects. This optimized design effectively solves the problem of incomplete combustion of the premixed gas caused by residual air in the main explosion container. The positive pressure protective environment created by inert gas purging significantly improves the explosion trigger rate. The complete monitoring system ensures the comprehensiveness of the experimental data and the accuracy of the analysis. In practice, inert gas is introduced into the main explosion container from a cylinder through pipelines to thoroughly purge residual air. The monitoring system includes various sensors and a high-speed camera, simultaneously recording pressure, temperature, strain, acceleration, and visual data during the explosion. Argon or carbon dioxide can be used as the inert gas; advanced equipment such as infrared cameras or 3D scanners can be added to the monitoring system.

[0020] The beneficial effects that the experimental apparatus and method disclosed in this application for simulating continuous explosions in a confined space may bring include, but are not limited to: This invention, through the collaborative design of a "main explosion container (gas phase fuel) + sub-container (powder fuel)," achieves for the first time a simulation experiment of a secondary explosion triggered by the initial detonation of an oil and gas tanker truck inside a tunnel under laboratory conditions. This device overcomes the limitations of traditional single-gas phase detonation experiments by introducing combustible powder as a secondary energy source, thus reproducing the coupling mechanism between shock wave load and high-temperature fireball load. This design allows the lining structure to exhibit a more realistic damage evolution in the experiment, including radial crack systems generated under shock wave action, shear slip deformation under quasi-static pressure, and concrete spalling and bursting phenomena under thermal stress coupling. The invention features a clear structural design, strong controllability of operating conditions, and good repeatability. It provides a reliable experimental device for systematically studying the dynamic response law, damage accumulation mechanism, and damage assessment method of tunnel lining under combined explosive loads, and is of great significance for improving the blast-resistant design level and disaster prevention capabilities of tunnel engineering. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall system layout for the simulation experiment of tunnel lining response and damage under explosion load in the embodiment, showing the connection relationship between the tunnel model, explosion source, monitoring equipment and safety devices; Figure 2 This is a cross-sectional structural diagram of the tunnel model and monitoring system in the embodiment, showing the positioning of the main explosive container inside the lining, the layout of sensors, and the structure of the external quartz sand layer and explosion-proof observation window; Figure 3 This is a schematic diagram of the process of aluminum powder filling and antistatic fixing of the container in the embodiment, which shows the operation process of filling the micron-sized aluminum powder sub-container, putting it into the antistatic sealing bag, and fixing it to the main explosion container slot in sequence. Figure 4This is a schematic diagram of the system connection for nitrogen positive pressure protection of the main explosion container in the embodiment, illustrating the pipeline connection and pressure monitoring method between the nitrogen cylinder, pressure reducing valve, gas flow meter and the main explosion container; Figure 5 This is a schematic diagram of the system connection for propane and air premixed gas filling in the embodiment, showing the pipeline connection and concentration monitoring process of propane cylinder, air cylinder, gas mixer and main explosion container.

[0022] Illustrations: 1. Tunnel model; 2. Sealing cap; 3. Adjustable pressure relief valve; 4. High-speed camera; 5. Explosion-proof observation window; 6. Strain gauge; 7. Data acquisition instrument; 8. Accelerometer; 9. Thermocouple; 10. Computer; 11. Crack width gauge; 12. Detonator; 13. Pressure sensor; 14. Metal heat-conducting baffle; 15. Transparent or translucent granular layer; 16. Flange interface; 17. Main explosion container; 18. Antistatic sleeve; 19. Sub-container; 20. Slot; 21. Insulating tweezers; 22. Nitrogen cylinder; 23. Pressure gauge; 24. Gas flow meter; 25. Pressure reducing valve; 26. Gas mixer; 27. Propane cylinder; 28. Air cylinder; 29. ​​Gas analyzer. Detailed Implementation

[0023] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] The following uses a confined space model, specifically a tunnel model, to illustrate this application. It provides an experimental apparatus and method for simulating the damage caused by an explosion of an oil and gas tanker truck inside a tunnel. This apparatus can better simulate the entire process of the explosion chain reaction and the actual damage morphology to the tunnel structure.

[0026] like Figures 1-3 As shown, an experimental apparatus for simulating the damage caused by an oil and gas tanker explosion in a tunnel according to the present invention includes a tunnel model 1, a main explosion container 17 placed inside the tunnel model 1, and a sub-container 19 disposed inside the main explosion container 17. The tunnel is made of reinforced concrete. One end of the tunnel model 1 is equipped with an openable and closable sealing cover 2 with a sealing flange, and the top is equipped with an adjustable pressure relief valve 3. The model is fitted with an explosion-proof observation window 5, and the outer wall of the tunnel model 1 is covered with a transparent quartz sand layer to facilitate the recording of the tunnel surface damage process by a high-definition camera. The main explosion container 17 is a rigid PVC container, which is connected to an external fuel supply system via a sealed flange interface 16. This fuel supply system includes a gas flow meter 24 and a gas mixer 26, used to precisely fill the main explosion container 17 with a premixed gas of combustible gas and air to simulate the vapor cloud of an oil and gas tank. Before filling with the premixed gas, nitrogen can be filled into the main explosion container 17 through the interface to create a "positive pressure protection" environment, preventing the risk of external air entering when opened. The main explosion container 17 is equipped with an initiator 12, which can be a remote electric initiator 12, used to detonate the premixed gas to simulate the initial detonation; see details below. Figure 4 , Figure 4 This is a schematic diagram of the system connection for nitrogen positive pressure protection of the main explosion container 17 in this embodiment, illustrating the pipeline connection and pressure monitoring method between the nitrogen cylinder 22, pressure reducing valve 25, gas flow meter 24 and the main explosion container 17. This structure enables the main explosion container 17 to be filled with nitrogen to create a "positive pressure protection" environment. Details are as follows: First, connect the nitrogen cylinder 22 to the main explosion container 17 via the pressure reducing valve 25 and the gas flow meter 24 in a sealed manner. Use 0.1 MPa nitrogen gas with soapy water to check the sealing of each interface. After confirming there is no leakage, introduce 0.2 MPa nitrogen gas and maintain purging for 3 minutes. Use nitrogen gas to replace the gas inside the container and create a positive pressure protective environment. Purging involves continuously introducing nitrogen gas into the container to "drive out" the original air, other gases, or impurities.

[0027] The sub-container 19 is a borosilicate glass container encapsulated with combustible solids. Before being placed into the main explosion container 17, the sub-container 19 is first placed in an anti-static sealed bag to prevent the risk of static electricity generated by scratching during operation. It is then placed into a pre-set slot 20 inside the main explosion container 17 using insulated tweezers 21 to ensure its fixed position. The detonation effect of the main explosion container 17 can effectively tear apart the sub-container 19 and fully scatter the combustible powder inside, forming a combustible dust cloud that is ignited by a high-temperature fireball to simulate a secondary explosion.

[0028] The tunnel model 1 is also equipped with a pressure sensor 13 and a thermocouple 9, which are used to measure the time history changes of the pressure and temperature of the explosion shock wave, respectively; a metal heat-conducting baffle 14 is installed on the inner wall of the tunnel model 1 to guide heat circulation and prolong the high temperature action time. The tunnel model 1 is equipped with a damage monitoring system on the lining surface to collect the dynamic response of the lining structure under explosive load. The damage monitoring system includes strain gauges 6 and acceleration sensors 8, both of which are connected to the data acquisition instrument 7.

[0029] Preferably, the main explosion container 17 is made of a brittle material, and its burst pressure is lower than the strength limit of the tunnel model 1. The combustible powder is a metal powder, preferably aluminum powder. The combustible gas is liquefied petroleum gas, which is more realistic. The tunnel model 1 is prepared on a scaled-down basis according to a similarity ratio.

[0030] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0031] The experimental setup and methods described in this application are detailed below: I. Composition of the Experimental Apparatus Tunnel Model 1 System: Includes a C30 reinforced concrete tunnel model 1 (inner diameter 30cm, length 2m, wall thickness 5cm) prepared at a geometric similarity ratio of 1:20, with an internal Φ6mm steel mesh (spacing 10cm×10cm), and 20cm wide sealing flanges (with 6 bolt holes) at both ends; an adjustable pressure relief valve 3 (preset pressure relief 0.8MPa) is installed on the top of the model, and explosion-proof observation windows 5 with embedded high-strength tempered glass (thickness 12mm) are provided on the side walls, and a layer of transparent quartz sand with a particle size of 0.5-1mm is pasted on the outer wall.

[0032] The explosion source generation system includes a 500mL borosilicate glass sub-container 19 (filled with 5-10μm spherical aluminum powder), a 5L rigid PVC main explosion container 17, a nitrogen cylinder 22, a gas mixer 26 (preparing a 4% concentration of propane and air premixed gas), and a remote electric spark detonator 12 to trigger the composite explosion load.

[0033] Monitoring and acquisition system: includes pressure sensor 13, thermocouple 9, acceleration sensor 8, strain gauge 6 and other sensing devices; data acquisition instrument 7, high-speed camera 4, crack width meter 11. The data acquisition instrument 7 and crack width meter 11 are connected to an external computer 10 to complete the synchronous acquisition of multiple physical quantities and damage detection during the explosion process.

[0034] Safety protection system: including grounded workbench (grounding resistance ≤4Ω), anti-static equipment (gloves, sealed bags, clothing), 50m radius warning tape, and 3 emergency adjustable pressure relief valves, to ensure the safety and controllability of the experimental process.

[0035] Experimental methods and procedures Step 1: Tunnel Model 1 Preparation and Basic Assembly Based on the actual tunnel lining structure, a C30 reinforced concrete tunnel model 1 was constructed using a 1:20 geometric similarity ratio. The model has an inner diameter of 30cm, a length of 2m, and a wall thickness of 5cm. It contains an internal Φ6mm steel mesh (10cm x 10cm spacing), and 20cm sealing flanges (6 bolt holes) are pre-installed at both ends. Standard curing time is 28 days. An adjustable pressure relief valve 3 is installed at the top, and 12mm tempered glass explosion-proof observation windows 5 are embedded in the side walls. A transparent quartz sand layer is adhered to the outer wall. Pressure sensors 13, thermocouples 9, accelerometers 8, and strain gauges 6 are installed along the tunnel axis and circumferentially around the lining. The sensor wires are connected to a data acquisition instrument 7, completing the initial construction of the monitoring and sensing system.

[0036] Step 2: Filling and anti-static fixing of sub-container 19 Calibrate the electronic balance, ground the workbench, and have the operator wear anti-static gloves. Inspect and clean the 500mL borosilicate glass sub-container 19. Weigh 50.00g of 5-10μm spherical aluminum powder and accurately fill it into the sub-container 19. After sealing with a silicone stopper (soaking in clean water to remove air bubbles), place it in an anti-static sealed bag. Use PTFE tweezers to insert them into the bottom annular groove 20 of the main explosion container 17 (a 5L rigid PVC container) to secure the aluminum powder sub-container 19.

[0037] Step 3: Sealing and fuel filling of the main explosion container 17 A high-pressure resistant rubber gasket was installed and tightened at the flange interface 16 of the main explosion container 17. After connecting the stainless steel pipeline, a leak test was performed using soapy water, and 0.1 MPa nitrogen gas was introduced without any bubbles. Then, 0.2 MPa nitrogen gas was introduced to purge for 3 minutes to create a positive pressure protective environment. Subsequently, 4.0% ± 0.1% propane and air premixed gas was filled to 0.3 MPa using a gas mixer 26, and the concentration was verified using a portable gas analyzer 29. The sealing of the main explosion container 17 and the precise fuel filling were completed.

[0038] See details Figure 5 , Figure 5 This is a schematic diagram of the propane and air premixed gas filling system in this embodiment, illustrating the pipeline connections and concentration monitoring process between the propane cylinder 27, air cylinder 28, gas mixer 26, and main explosion container 17. Details are as follows: Using a gas mixer 26, the gases from propane cylinder 27 and air cylinder 28 are mixed in a ratio of 4.0% ± 0.1% to form a propane-air premixed gas. The flow rate is precisely controlled by a gas flow meter 24 and then injected into the main explosion container 17 until the pressure gauge 23 on the container shows a pressure of 0.3 MPa. Finally, a gas analyzer 29 connected to the container is used to detect and confirm that the premixed gas concentration meets the requirements, thus completing the sealing and fuel filling process of the main explosion container 17.

[0039] Step 4: Monitoring System Integration and Debugging Complete the connection between the sensor wires and the data acquisition device 7, and simultaneously install the high-speed camera 4 outside the tunnel model 1; start the data acquisition device 7 and preheat it for 30 minutes, verifying the sensor signal is free of noise and has a sensitive response by tapping and pressing. Start the high-speed camera 4 to record a 10-second blank video, check the image clarity and confirm that the external hard drive has sufficient storage space; fix the main explosive container 17 to the midpoint of the central axis inside the tunnel model 1 with expansion bolts, ensuring that it is placed horizontally and that the distance between it and the tunnel wall is uniform in all directions.

[0040] Step 5: Tunnel Sealing and Detonation Preparation After closing the sealing caps 2 at both ends of the tunnel and installing the high-pressure resistant rubber sealing gaskets, the flanges are symmetrically tightened with bolts. 0.1MPa air is introduced and pressurized for 10 minutes to confirm no leakage. At the same time, the opening flexibility and preset pressure of the adjustable pressure relief valve 3 are checked. A warning tape with a radius of 50m is set up in the experimental area. After the operators wear anti-static clothing, protective masks, and impact-resistant gloves, they are evacuated to the safety control room. The connection between the remote electric detonator 12 and the electrodes inside the main explosive container 17 is checked. The detonation signal is tested by remote control to ensure that the connection is normal.

[0041] Step 6: Explosion Triggering and Data Acquisition The operator presses the remote control detonation button in the safety control room, triggering the electric detonator 12 inside the main explosion container 17 to detonate the premixed gas. The initial detonation tears the main explosion container 17 and then further tears the sub-container 19. Aluminum powder is scattered to form a dust cloud, which is ignited by the high-temperature fireball, causing a secondary explosion. The data acquisition instrument 7 simultaneously records the shock wave pressure time history, temperature field change curve, and lining strain / acceleration dynamic signal for 30 minutes. The high-speed camera 4 captures 60 seconds of the entire process of the initial detonation flame propagation, secondary explosion dust cloud formation and combustion, and lining surface damage. During the explosion, the status of the tunnel model 1 is monitored in real time through the explosion-proof observation window 5 in the safety control room. If abnormal deformation or leakage occurs, the emergency adjustable pressure relief valve 3 is immediately activated.

[0042] Step 7: Post-experiment processing and data analysis After the explosion, the tunnel was left to stand for 2 hours until the temperature inside the tunnel dropped to room temperature and the pressure returned to normal. Operators, wearing protective gear, entered the experimental area, opened the tunnel sealing cover 2 and the adjustable pressure relief valve 3, and used an anti-static vacuum cleaner to clean away any remaining aluminum powder and concrete debris. Container remains were collected and stored separately. A crack width meter 11 was used to measure the length, width, and depth of cracks on the lining surface. A measuring tape was used to measure the area of ​​the spalled-off region. High-resolution photographs were taken, and the location and size of the damage were marked. Simultaneously, the condition of the sensors was checked. All monitoring equipment was removed, and the wiring and data acquisition instrument 7 were organized. Pressure, temperature, strain, and acceleration data from the data acquisition instrument 7 were exported, and time-history curves were plotted. The pressure peak, arrival time, and temperature duration of the initial and secondary detonations were analyzed. Combined with high-speed camera footage to track crack propagation speed and flame propagation paths, the failure mode and damage degree of the tunnel lining were finally assessed. Comparative analysis of experimental results under different working conditions: I. Different types of premixed gas in the main explosion container

[0043] II. The premixed gas pressure in the main explosion container is different (gas type: propane, concentration 4%).

[0044] III. The types and qualities of powders in the sub-containers differ (Main explosion container: propane 0.3MPa)

[0045] IV. Different tunnel system parameters (Main explosion container: propane + 0.3MPa; Sub-container: aluminum powder 50g)

[0046] V. Different initial environmental parameters (Main explosion container: propane + 0.3 MPa; Sub-container: 50 g aluminum powder)

[0047] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An experimental apparatus for simulating continuous explosions in a confined space, characterized in that, include: Constrained space model; The main explosion container (17) is placed inside the confined space model to contain the first flammable medium and is equipped with an initiator (12). Sub-container (19), disposed inside the main explosion container (17), is used to contain a second flammable medium; The main explosion container (17) is configured to rupture upon detonation and tear apart the sub-container (19), causing the second flammable medium to spill out and be ignited, thereby simulating the secondary explosion process triggered by the initial detonation.

2. The apparatus according to claim 1, characterized in that, The confined space model is a tunnel model (1), a lane model, or a pipeline model.

3. The apparatus according to claim 1 or 2, characterized in that, The main explosion container (17) is connected to the external fuel supply system through a sealed interface; the sub-container (19) is fixed inside the main explosion container (17) through a slot (20) or a bracket, and the sub-container (19) is covered with an antistatic sleeve (18).

4. The apparatus according to claim 3, characterized in that, The main explosion container (17) is made of rigid PVC or other brittle non-metallic materials; the sub-container (19) is made of borosilicate glass or other brittle materials.

5. The apparatus according to claim 1, characterized in that, The confined space model is equipped with at least one of the following: a sealing cover (2), an adjustable pressure relief valve (3), and an explosion-proof observation window (5).

6. The apparatus according to claim 5, characterized in that, The confined space model is equipped with a sensor system for monitoring explosive loads. The sensor system includes at least one of a pressure sensor (13), a thermocouple (9), a strain gauge (6), a high-speed camera (4), and an acceleration sensor (8).

7. The apparatus according to claim 6, characterized in that, The outer wall of the confined space model is covered with a transparent or translucent granular layer (15) to assist in preventing damage to the surface of the optical recording structure.

8. The apparatus according to claim 1, characterized in that, The first combustible medium is a premixed gas of combustible gas and air; the second combustible medium is metal powder or coal powder.

9. A method for simulating continuous explosions in a confined space, characterized in that, Using the apparatus as described in any one of claims 1-8, and comprising the following steps: The second flammable medium is filled into the sub-container (19) and fixed inside the main explosion container (17); The main explosion container (17) is placed within a confined space model; The first flammable medium is introduced into the main explosion container (17); The first flammable medium is detonated to generate an initial detonation that tears apart the main and sub-containers (19) and spills the second flammable medium, thereby triggering a secondary explosion.

10. The method according to claim 9, characterized in that, Before filling the first combustible medium, inert gas is first filled into the main explosion container (17) for purging; and physical parameters and images during the explosion process are recorded by a monitoring system to analyze the damage effect of the explosion on the confined space model.

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