Experimental platform and method for simulating the leakage and diffusion of toxic gases under obstacle movement conditions

Abstract

This invention discloses an experimental platform and method for simulating the leakage and diffusion of toxic gases under obstacle movement conditions. The experimental platform includes a toxic gas leakage model, a gas release system, and a data acquisition system. The toxic gas leakage model includes a gas diffusion chamber and a movable obstacle. The movable obstacle consists of obstacle components and a moving component, the moving component being a wirelessly controlled remote-controlled vehicle model whose speed can be controlled remotely. The gas release system includes a gas storage device, a flow control device, and a connecting conduit. The data acquisition system includes gas detection instruments, a camera, a thermometer, and a hygrometer for data acquisition within the diffusion chamber. This invention can effectively simulate the impact of turbulence generated by obstacle movement on the leakage and diffusion of toxic gases, thereby obtaining accurate experimental data. It can provide reliable experimental and data support for research on large-scale personnel evacuation and emergency rescue in toxic gas diffusion scenarios.

Description

Technical Field

[0001] This invention belongs to the field of environmental and industrial safety toxic gas diffusion simulation research technology, specifically involving an experimental platform and method for simulating the leakage and diffusion of toxic gases under obstacle movement conditions. Background Technology

[0002] my country is transitioning from a major chemical producer to a leading chemical power, leading to increasingly stringent requirements for chemical safety. Chemical production processes are complex, involving specialized materials and toxic substances such as hydrogen fluoride and chlorine. Due to human error, equipment failure, and weak safety management, toxic gas leaks can occur at any time. Accidental releases of toxic gases are typically accompanied by large-scale evacuations, and the traffic forces generated by large-scale population movement significantly disrupt the surrounding airflow. Therefore, research on the diffusion of toxic gases under obstacle movement conditions is essential, providing a basis for decision-making in evacuation and emergency response.

[0003] In related technologies, very few studies conduct full-scale diffusion experiments when conducting experiments on the diffusion of toxic gas leaks. This is mainly because large-scale experiments are costly, have poor repeatability, and the large-scale release of toxic gases can have unpredictable consequences for people and the environment. Furthermore, existing research primarily focuses on the diffusion of toxic gases under fixed obstacles or different terrain conditions, where the objects are stationary. There is little research on the impact of large-scale population movement caused by toxic gas leaks and the resulting traffic forces on surrounding airflow. Computational fluid dynamics (CFD) has been widely used to simulate fluid motion under complex conditions and can simulate gas diffusion over obstacles relatively well. However, when studying toxic gas diffusion using CFD, the numerical model needs to be validated first. Therefore, in this field, researchers mainly conduct small-scale experiments, scaling down the experimental model proportionally based on the principle of similarity. Based on the results of the small-scale experiments, the CFD model is then modified. Once the CFD simulation results pass the model evaluation criteria, more detailed flow information about gas diffusion can be obtained from the numerical model. Furthermore, based on this model, the model scale can be further expanded to study the diffusion patterns of different types of toxic gases under complex conditions. Therefore, establishing an experimental platform that can simulate the diffusion of toxic gas leaks under obstacle movement conditions, specifically for large-scale evacuations triggered by accidental toxic gas leaks in such industrial accidents, and studying the impact of traffic forces caused by moving objects on the diffusion of toxic gases, can provide technical guidance and data support for emergency rescue and personnel evacuation in such accidents. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an experimental platform and method for simulating the leakage and diffusion of toxic gases under obstacle movement conditions. Using this experimental platform, the impact of traffic forces generated by obstacle movement on the leakage and diffusion of toxic gases can be studied, thereby providing technical guidance for actual toxic gas leakage detection and personnel evacuation.

[0005] The technical solution of this invention is as follows:

[0006] An experimental platform for simulating the leakage and diffusion of toxic gases under obstacle movement conditions includes a toxic gas diffusion model, a gas release system, and a data acquisition system.

[0007] The toxic gas diffusion model includes a gas diffusion chamber with an air inlet at the bottom and openable doors on the front and rear sides for easy operation and gas exhaust. A movable obstacle is installed inside the gas diffusion chamber, which consists of obstacle components and moving components.

[0008] The gas release system includes a gas storage device, a conduit, and a flow control device. The gas storage device is used to store the gas used in the experiment. The flow control device is used to control the volumetric flow rate of the gas and thus control the initial flow rate of the nozzles inside the chamber. The conduit is used to connect the gas storage device, the flow control device, and the nozzles inside the gas diffusion chamber.

[0009] The data acquisition system includes a gas detection instrument, a camera, a thermometer, and a hygrometer. The thermometer and hygrometer are used to obtain the temperature and humidity conditions inside the diffusion chamber. The camera is used to record the experimental process. The gas detection instrument is used to detect the concentration of toxic gases inside the diffusion chamber and to monitor and record it in real time.

[0010] Preferably, the walls of the gas diffusion chamber are made of plexiglass panels, allowing personnel to observe the experimental conditions inside the chamber. The seams of the plexiglass panels are sealed with silicone sealant to prevent accidental gas leakage and reduce experimental accuracy.

[0011] Preferably, the movable obstacle is divided into two parts: an obstacle component and a moving component; the obstacle component is a high-density foam board, which can be perforated and shaped; the moving component is a wireless remote-controlled vehicle, which is placed inside the obstacle component. The movement and speed of the object can be controlled by a remote control terminal, and the shape and size of the foam board can be changed as required to study the effect of different windward areas on the diffusion of toxic gases.

[0012] Preferably, the height of the gas inlet can be adjusted according to experimental needs.

[0013] Preferably, the gas storage device in the gas release system is a pressure tank, which is equipped with a pressure gauge and a pressure reducing valve. The pressure gauge is used to observe the internal pressure of the tank, and the pressure reducing valve is used to open the pressure tank. Together with the pressure gauge, they ensure a reasonable pressure output from the gas storage device.

[0014] Preferably, the toxic gas in the gas release system is CO2, which is low in toxicity, easy to handle, and harmless to the environment.

[0015] Preferably, the flow control device in the gas release system includes a flow display and a flow controller. The flow display is used to display the current gas flow rate, and the flow controller is used to regulate the gas mass flow rate. The range of the flow control device is 0-30 L / min.

[0016] Preferably, the gas detection instrument monitors the gas concentration in the experimental platform by infrared detection. The infrared gas detector operates at a DC voltage of 7-24V, has a range of 400-5000ppm, a measurement accuracy of ±(50ppm + 5% of the reading), and a resolution of 1ppm.

[0017] Preferably, the gas detector is installed at the bottom, side and top of the gas diffusion chamber to obtain the gas concentration at different locations inside the diffusion chamber.

[0018] An experimental method based on the above-mentioned experimental platform for simulating the leakage and diffusion of toxic gases under obstacle movement conditions includes the following steps:

[0019] S1. Construct a gas leakage diffusion model and a movable obstacle. Place the movable obstacle at the bottom centerline, with a distance of 0.4m from the nozzle. Do not connect the duct to the nozzle inside the chamber at first.

[0020] S2. Open the gas release system, adjust the gas flow rate using the flow controller, and then close the gas release system.

[0021] S3. Connect the conduit to the nozzle and turn on the data acquisition system, including gas detection instruments, thermometer and hygrometer;

[0022] S4. Close the hatch, open the gas release system, observe and record the diffusion of toxic gases in the diffusion chamber and the ambient temperature and humidity; set the time for the obstacle to start moving. After 60 seconds of leakage, the obstacle will start moving at a constant speed and stop moving when it reaches the rear wall of the diffusion chamber.

[0023] S5. Set the gas release time. After the time requirement is met, save the collected data, shut down the gas release system, open the hatch, turn on the ventilation system, and keep the experimenters away from the experimental area. Monitor the gas concentration remotely. When the gas concentration drops to the range allowed by the environment, shut down the ventilation system and the data acquisition system.

[0024] The beneficial effects of this invention are:

[0025] This invention provides an experimental platform and method for simulating the leakage and diffusion of toxic gases under conditions of moving obstacles. The platform is simple in construction, easy to operate, and rationally designed, effectively simulating the leakage and diffusion of toxic gases to obtain valid experimental data. This invention studies the diffusion of toxic gases under conditions of moving obstacles, where the obstacles are no longer fixed. This provides sufficient data support for studying the impact of turbulence caused by movable obstacles on toxic gas leakage, thus providing technical guidance for actual emergency rescue and personnel evacuation. The toxic gas used in this invention is CO2, which has low toxicity, is easy to handle, and is harmless to the environment, ensuring the safety of experimental personnel. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0027] Figure 1 This is a schematic diagram of the structure of an experimental platform for simulating the leakage and diffusion of toxic gases under obstacle movement conditions, which includes a gas diffusion model, a gas release system, and a data acquisition system.

[0028] Figure 2 It refers to movable obstacles and their components;

[0029] The following are labeled in the diagram: 1. Gas storage device; 2. Pressure relief valve; 3. Pressure gauge; 4. Conduit; 5. Flow controller; 6. Flow display regulator; 7. Camera; 8. Nozzle; 9. Gas detector; 10. Rear door; 11. Data processor; 12. Front door; 13. Acrylic glass panel; 14. Support frame; 15. Wire; 16. Movable obstacle; 17. Moving part; 18. High-density foam board.

[0030] Figure 3 (a) is a graph showing the trend of gas concentration over time detected at gas concentration monitoring point (a); Figure 3 (b) is a graph showing the trend of gas concentration over time detected at gas concentration monitoring point (b); Figure 3 (c) is a graph showing the trend of gas concentration over time detected at gas concentration monitoring point (c); Figure 3 (d) is a schematic diagram of the distribution of gas concentration monitoring points. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0032] like Figure 1-2 As shown, an experimental platform for simulating the leakage and diffusion of toxic gases under obstacle movement conditions includes a toxic gas diffusion model, a gas release system, and a data acquisition system.

[0033] The toxic gas diffusion model includes a gas diffusion chamber with an air inlet at the bottom and operable doors on the front and rear sides for easy operation and gas exhaust. For example, the front door 12 is located on the front side of the diffusion chamber, and the rear door 10 is located on the rear side. A movable obstacle 16 is installed inside the gas diffusion chamber, consisting of an obstacle component and a moving component 17. The obstacle component is a high-density foam board 18. Preferably, the high-density foam board 18 is made of EPS (polystyrene foam) with a foam density of 25K. The high-density foam board 18 can be perforated and shaped internally. The moving component 17 is a wireless remote-controlled vehicle. The moving component is placed inside the obstacle component, and its movement and speed can be controlled remotely. Furthermore, the shape and size of the high-density foam board 18 can be changed as needed to study the effect of different windward areas on the diffusion of toxic gases.

[0034] The gas release system includes a gas storage device 1, a pressure relief valve 2, a pressure gauge 3, a conduit 4, a flow controller 5, and a flow display regulator 6. The gas storage device 1 is connected to the flow controller 5 and a nozzle 8 via the conduit 4. The pressure relief valve 2 and the pressure gauge 3 are installed on the conduit 4. The flow controller is connected to the flow display regulator 6. The gas storage device 1 is a high-pressure gas cylinder containing high-purity carbon dioxide gas with a purity of 99.9%, and its normal operating pressure does not exceed 10 MPa. The pressure relief valve 2 is located at the top of the gas storage device 1. The gas storage device can be opened and closed via the pressure relief valve 2. After opening the pressure relief valve 2, the initial gas pressure will be displayed on the pressure gauge 3. The pressure gauge 3 allows observation of the internal gas pressure of the gas storage device, and the gas output pressure can be adjusted to a suitable value via the pressure relief valve 2. The gas ejected from the gas storage device 1 flows through the conduit 4 to the flow controller 5. The gas flow rate is controlled by the flow display regulator 6. By rotating the knob of the flow display regulator 6, the gas flow rate can be increased or decreased. The gas flow rate can be observed in real time on the display panel of the flow display regulator 6. The range of the flow control device is between 0-30L / min.

[0035] The toxic gas diffusion model includes a nozzle 8, a rear door 10, a front door 12, an acrylic plate 13, a support 14, and a movable obstacle 16. Gas flows through the flow regulator 5 to the nozzle 8. In this embodiment, the nozzle 8 has a diameter of 6.5 mm and a height of 10 mm, spraying carbon dioxide gas vertically upwards. The size of the nozzle 8 can be modified according to experimental design requirements, and nozzles with different leakage diameters and outlet heights can be used to achieve experimental conditions with different leakage volumes and heights. The nozzle 8 is installed at the centerline of the bottom of the diffusion chamber, 200 mm away from the front door 12, ensuring that the leakage direction and location are consistent in each experiment. Furthermore, in practice, leakage outlets can be placed at different locations at the bottom of the diffusion chamber as needed. The movable obstacle is placed 400 mm behind the nozzle, and its aspect ratio, height-to-width ratio, or geometry can be changed according to actual requirements and research content. The door closer to nozzle 8 is designated as the front door 12, and the door farther from nozzle 8 is designated as the rear door 10. Both doors can be opened and closed freely, and their height and width are both 1200mm. The front and rear doors facilitate the installation and design of the experimental apparatus within the diffusion chamber, and also accelerate gas exhaust. The main frame of the diffusion chamber consists of plexiglass panels 13 and a support frame 14. The support frame 14 is made of high-strength aluminum profiles, through which plexiglass panels 13 can be inserted. The top and left and right sides of the diffusion chamber are also constructed of plexiglass panels 13, allowing researchers to easily observe the experimental conditions inside. To ensure the airtightness of the diffusion chamber and reduce interference from unstable factors, silicone sealant is injected into both sides of the aluminum profile joints after the plexiglass panels 13 are installed.

[0036] The data acquisition system includes a camera 7, gas detectors 9, a data processor 11, and wires 15. The camera 7, used to record the experimental process, is placed in front of the front door 12, at the center line of the door. Multiple gas detectors 9 are installed at the bottom and top of the diffusion chamber. The gas detectors 9 at the bottom of the diffusion chamber are placed in a straight line with the nozzles 8 at equal intervals, while the gas detectors 9 at the top of the diffusion chamber are placed at equal intervals. These gas detectors 9 are connected in series via wires 15 and connected to the data processor 11. The gas detectors 9 are sensors. The operating voltage of the gas detectors 9 is 7-24V DC. The gas detection instrument has a range of 400-5000ppm, a measurement accuracy of ±(50ppm + 5% of the reading), and a resolution of 1ppm. Each sensor needs to be connected to a DC power converter for power supply. The series connection prevents all sensors from simultaneously monitoring the real-time gas concentration at different locations. By setting the monitoring frequency, the next sensor will only monitor the concentration after the previous sensor has completed its monitoring. Finally, the data monitored by the gas detectors 9 cannot be used directly and needs to be imported into the data processor 11 for post-processing. In addition, the data acquisition system includes an environmental temperature and humidity meter to measure the temperature and humidity of the environment, ensuring the stability of experimental conditions. The temperature and humidity meter is located inside the diffusion chamber.

[0037] The gas used in the experiments of this invention is CO2. The toxic gas in the gas release system is CO2, which is low in toxicity, easy to handle, and harmless to the environment.

[0038] The experimental method based on the above-mentioned experimental platform for simulating the leakage and diffusion of toxic gases under obstacle movement conditions includes the following steps:

[0039] S1. Construct a gas leakage diffusion model and a movable obstacle. Place the movable obstacle 16 at the bottom centerline of the diffusion chamber, with a distance of 0.4m from the nozzle 8. Do not connect the conduit 4 to the nozzle 8 inside the chamber at first.

[0040] S2. Open the gas release system, adjust the gas flow rate through the flow controller 5, and close the gas release system;

[0041] S3. Connect the conduit 4 to the nozzle 8 and turn on the data acquisition system 11, which includes the gas detector 9, thermometer and hygrometer.

[0042] S4. Close the hatch, open the gas release system, observe and record the diffusion of toxic gas in the diffusion chamber and the ambient temperature and humidity; set the starting time for the movable obstacle 16 to move. After 60 seconds of leakage, the obstacle 16 will start to move at a constant speed and stop moving when it reaches the rear wall of the diffusion chamber.

[0043] S5. Set the gas release time. After the time requirement is met, save the collected data, shut down the gas release system, open the hatch, turn on the ventilation system, and keep the experimenters away from the experimental area. Monitor the gas concentration remotely. When the gas concentration drops to the range allowed by the environment, shut down the ventilation system and the data acquisition system.

[0044] To verify the reliability of the experimental platform, two coupled experiments involving obstacle movement and gas release at different speeds were conducted inside the chamber. Figure 3 (d) is a schematic diagram of the distribution of gas concentration monitoring points. Gas concentration monitoring points (a), (b) and (c) are set on the side wall near the bottom of the diffusion chamber. Gas detectors 9 are set on these three gas concentration monitoring points respectively. The distances of the three gas detectors 9 from the front side 12 are 380mm, 2015mm and 4390mm respectively, and the distances from the bottom are all 300mm. Figure 3 (a) is a graph showing the trend of gas concentration over time at monitoring point (a). Figure 3 (b) is a graph showing the trend of gas concentration over time as detected at gas concentration monitoring point (b). Figure 3 (c) is a graph showing the trend of gas concentration over time detected at gas concentration monitoring point (c). Figure 3 (a)- Figure 3 (c) It can be seen that the change in velocity has little effect on the concentration at each point, and the main effect is shown in the elliptical area in the figure (after the gas concentration rises to a certain level, there will be a period of slower concentration increase). In addition, the increase in moving speed advances the initial time of gas concentration increase to some extent. The main reasons for the small impact here are as follows: First, the change in velocity is small, and the turbulent kinetic energy it generates is not significant; second, the measuring point is on the wall rather than in the middle of the chamber, so the real-time change in concentration is not drastic.

[0045] Based on this data, a geometric and turbulence model can be established at a 1:1 scale in the CFD model. By comparing the simulation results with experimental values, a reliable CFD model can be established. This model can then be applied to full-scale environments to establish a reliable numerical relationship between the traffic forces generated by vehicles and personnel moving after the accidental release of toxic gases in urban environments or chemical plant scenarios and the diffusion and spread of toxic gases. This provides an important reference for personnel evacuation and emergency response.

[0046] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A platform capable of simulating the leakage and diffusion of toxic gas under the condition of obstacle movement, characterized in that, The system comprises a toxic gas diffusion model, a gas releasing system and a data acquisition system. The toxic gas diffusion model comprises a gas diffusion cabin, which is provided with an air inlet at the bottom and cabin doors at the front and back sides, which can be opened and closed for the convenience of personnel operation and gas discharge; a movable barrier is arranged in the gas diffusion cabin, which is composed of a barrier component and a moving component. The gas releasing system comprises a gas storage device, a pressure relief valve, a pressure gauge, a conduit, a flow controller and a flow display regulator; the gas storage device is connected with the flow controller and the nozzle in sequence through the conduit; the pressure relief valve and the pressure gauge are arranged on the conduit; the flow controller is connected with the flow display regulator; the gas storage device is a high-pressure gas cylinder, which stores high-purity carbon dioxide gas with a purity of 99.9%, and the normal working pressure is not higher than 10 MPa; the upper part of the gas storage device is provided with a pressure relief valve, which can be opened and closed; after the pressure relief valve is opened, the initial pressure of the gas can be displayed on the pressure gauge; the pressure inside the gas storage device can be observed through the pressure gauge, and the gas output pressure can be adjusted to a suitable value through the pressure relief valve; the gas discharged from the gas storage device flows to the flow controller through the conduit; the gas flow is set by the flow display regulator; the gas flow can be increased or decreased by rotating the flow display regulator knob; the gas flow can be observed in real time on the display disc of the flow display regulator; the range of the flow control device is between 0-30L / min. The data acquisition system comprises a gas detection instrument, a camera, a thermometer and a hygrometer; the thermometer and the hygrometer are used to obtain the temperature and humidity in the diffusion cabin; the camera is used to record the experimental process; the gas detection instrument is used to detect the concentration of toxic gas in the diffusion cabin and to monitor and record it in real time. 2.The platform of simulating the leakage and diffusion of toxic gas under the condition of moving obstacles according to claim 1, wherein, The wall of the gas diffusion cabin is composed of organic glass plates, which can enable personnel to observe the experimental conditions in the cabin; the joints of the organic glass plates are sealed by glass glue. 3.The platform of claim 1, wherein, The barrier component is a foam plate, which can be drilled and shaped inside; the moving component is a wireless remote control car; the moving component is placed inside the barrier component; the movement and speed control of the object can be realized through the remote control end; the shape and size of the foam plate can be changed according to requirements to study the influence of different wind areas on the diffusion of toxic gas. 4.The platform of claim 1, wherein, The height of the gas inlet of the nozzle can be adjusted according to experimental needs. 5.The platform of simulating the leakage and diffusion of toxic gas under the moving obstacle condition according to claim 1, wherein, The gas detection instrument monitors the gas concentration in the experimental platform by infrared detection; the working voltage of the gas detection instrument is 7-24v DC; the range of the gas detection instrument is 400-5000ppm; the measurement accuracy of the gas detection instrument is ±(50ppm+5% of the reading value); the resolution is 1ppm. 6.The platform of simulating the leakage and diffusion of toxic gas under the moving obstacle condition according to claim 1, wherein, The gas detector is installed at the bottom, side and upper part of the gas diffusion cabin to obtain the gas concentration at different positions in the diffusion cabin.

7. An experimental method based on the experimental platform for simulating the leakage and diffusion of toxic gas under the condition of obstacle movement according to any one of claims 1-6, characterized in that, The method comprises the following steps: S1, build gas leakage diffusion model, build movable obstacles, place the movable obstacles at the bottom center line, the distance between the nozzle and the movable obstacles is 0.4m, the conduit is not connected with the nozzle in the cabin at first; S2, open the gas release system, adjust the gas flow through the flow controller, close the gas release system; S3, connect the conduit with the nozzle, open the data acquisition system, including gas detection instrument, thermometer and hygrometer; S4, close the cabin door, open the gas release system, observe and record the diffusion of toxic gas in the diffusion cabin and the environmental temperature and humidity; set the start time of the movement of the obstacles, when the leakage is 60s, the obstacles start to move at a constant speed, and stop when reaching the back wall of the diffusion cabin; S5, set the gas release time, save the collected data after reaching the time requirement, close the gas release system, open the ventilation system, the experimenters leave the experimental area, monitor the gas concentration through remote control, when the gas concentration is reduced to the allowable concentration range of the environment, close the ventilation system, close the data acquisition system.

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