Experimental device for combustion and explosion characteristics of hydrogen-blended natural gas and explosion prevention / suppression synergistic effect under the influence of multiple parameters and its performance testing method

Abstract

The invention discloses a test device for the explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters and a performance test method thereof, and belongs to the field of safety of petrochemical enterprises; the test device comprises: a visualization explosion system, an ignition system, an air supply system, a powder spray explosion suppression system, a pressure spray system, an explosion prevention system, an obstacle system, an image acquisition system, a schlieren acquisition system, an oil bath heating / cooling system, a flow field control system, a pressure acquisition system, a temperature acquisition system, an ion detection system, a humidity control system, a synchronous control system, and a program control and data acquisition system; the invention realizes the research on the suppression mechanism of the explosion, explosion suppression, explosion prevention and synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters and the evolution mechanism of the flame propagation dynamic characteristics by changing multiple working conditions, and fills the gap of the performance test device for the explosion characteristics, explosion suppression, explosion prevention and synergistic effect mechanism and the evolution mechanism of the flame propagation dynamic characteristics of hydrogen-blended natural gas under the influence of multiple factors.

Description

Technical Field

[0001] The invention belongs to the field of petrochemical enterprise safety, and in particular relates to a test device for the combustion and explosion characteristics of hydrogen-blended natural gas and the explosion prevention / suppression synergistic effect under the influence of multiple parameters and a performance testing technology thereof. Background Art

[0002] With the rapid transformation of the energy structure and the formulation of the dual carbon goals of energy conservation and emission reduction, hydrogen-blended natural gas technology has been widely used and developed. Because of its green and clean characteristics, it can reduce carbon emissions during natural gas combustion. The transportation technologies of hydrogen-blended natural gas include long tank trailers, liquid hydrogen tank trucks and pipelines. Pipeline transportation has the characteristics of large transportation volume, long distance and low energy loss, and is currently the main mode of transportation. However, the addition of hydrogen can easily cause hydrogen embrittlement to natural gas storage and transportation equipment, and even cause equipment failure and gas leakage. Both natural gas and hydrogen are flammable and explosive gases. It is of great significance to understand the combustion and explosion characteristics of hydrogen-blended natural gas and take effective protective measures to prevent hydrogen-blended natural gas explosion accidents.

[0003] At present, the research on hydrogen-blended natural gas explosion is mostly focused on the macroscopic combustion and explosion characteristics, and there are few studies on the microstructure of the explosion flow field and the flow field change characteristics. The research that has been carried out is not enough to reveal the dynamic characteristics and influencing mechanism of hydrogen-blended natural gas explosion under the influence of multiple parameters. This requires in-depth development of experimental equipment that can meet the combustion and explosion characteristics of hydrogen-blended natural gas and its influencing factors and mechanisms, which has theoretical and practical significance for improving the theory of gas explosion. At the same time, flame arresters are often used in gas pipeline transportation to block the explosion flame in the pipeline. Once they fail, they will cause explosion accidents and cause a large number of casualties and serious economic losses. The current research on flame arresters is still imperfect in terms of theory and testing equipment and technology, and it is difficult to meet the growing requirements for energy safety use. In the face of hydrogen-blended natural gas with higher equipment requirements, how to achieve effective suppression and master the influence law and mechanism of explosion-proof characteristics, and establish an accurate correspondence between the critical explosion rate and pressure and the structural parameters of the flame arrester is crucial. In addition, when the flame arrester fails to block the flame, it is necessary to take effective secondary protection measures. However, there are still deficiencies in the selection of hydrogen-blended natural gas explosion suppressants, the types of explosion suppressants and their physical parameters for the suppression law and mechanism of explosion flames, and no complete theoretical system standard has been formed. In addition, the current focus is on explosion suppression in a single protection method, and there is a lack of research on the synergistic suppression of explosion prevention / suppression. Therefore, it is difficult to form a relatively complete theoretical guidance, let alone reveal the mechanism of group suppression / explosion synergy and establish an effective physical model. This requires the mastery of accurate and detailed experimental data on the explosion characteristics, explosion prevention, explosion suppression, and synergistic effects of hydrogen-blended natural gas as theoretical support, and then improve the explosion suppression theory to provide scientific ideas and theoretical basis for the research and development of combustible gas explosion protection. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters and its performance testing technology, including a visualization explosion system, an ignition system, an air supply system, a powder spray explosion suppression system, a pressure spray system, an explosion prevention system, an obstacle system, an image acquisition system, a schlieren acquisition system, an oil bath heating / cooling system, a flow field control system, a pressure acquisition system, a temperature acquisition system, an ion detection system, a humidity control system, a synchronous control system, and a program control and data acquisition system.

[0005] The test device for the explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters and its performance testing technology are characterized by: including a visual explosion system, an ignition system, an air supply system, a powder spray explosion suppression system, a pressure spray system, an explosion prevention system, an obstacle system, an image acquisition system, a schlieren acquisition system, an oil bath heating / cooling system, a flow field control system, a pressure acquisition system, a temperature acquisition system, an ion detection system, a humidity control system, a synchronous control system, and a program control and data acquisition system.

[0006] The visualization explosion system is divided into two structural forms: closed and open. Under the closed structure: the visualization explosion system consists of a visualization explosion container 1, container end cover flanges 2-1, 2-2, a visualization window 3 and an exhaust valve 17, and is sealed by bolt connection. The visualization explosion container 1 is a vertical rectangular structure, and visualization windows 3 are installed in front and behind it to observe the flame propagation dynamics characteristics and flow field microstructure evolution process under the combustion, explosion prevention, explosion suppression and synergistic effect of hydrogen-blended natural gas. In particular, the precise flame propagation speed and morphological evolution process when entering the flame arrester, the flame propagation characteristics and re-ignition development process at the rear end of the flame arrester, the microstructural evolution process of the reverse propagation of the pressure wave under the action of the flame arrester, and the morphological evolution of the explosion flame and the change characteristics of the flow field microstructure under the action of the explosion suppressant. Under the open structure: the visualization explosion system consists of a visualization explosion container 1, a visualization window 3, an explosion relief membrane 39, a container end cover flange 2-2 and an end face explosion relief flange 40. The membrane breaking strength can be adjusted by changing the thickness, number of layers and material of the explosion relief membrane 39; the explosion relief area can be adjusted by changing the opening size of the end face explosion relief flange 40. The exhaust valve 17 is installed on the upper right wall of the visual explosion container 1 to discharge the explosion products. The vacuum pressure gauge 20-3 measures the internal pressure of the visual explosion container 1, is connected to it through a pipeline, and a ball valve is installed between the two for protection. The ball valve is connected to the left side of the vacuum pressure gauge 20-3 and is connected in parallel with the compressor 30 and the vacuum pump 31 respectively. The initial pressure (overpressure) at the time of detonation is regulated by the compressor 30; at the same time, the explosion products inside the visual explosion container 1 can also be purged to achieve the replacement of fresh air from the outside with the products inside the container. The initial pressure (vacuum degree) at the time of detonation inside the visual explosion container 1 is regulated by the vacuum pump 31.

[0007] The ignition system is composed of an ignition electrode 6, an adjustable high-voltage igniter 32, a synchronous controller 24 and a program control and data acquisition system 25. The ignition of the hydrogen-blended natural gas premix is ​​achieved by high-voltage arc discharge. The ignition electrode 6 is threadedly installed on the lower part of the left and right walls of the visual explosion container 1 and is 100 mm high from the container end cover flange 2-2. The ignition energy is controlled by the adjustable high-voltage igniter 32, and the influence of the ignition energy on the explosion parameters and flame propagation characteristics of hydrogen-blended natural gas is studied, and the minimum ignition energy of hydrogen-blended natural gas under different working conditions is determined; including the influence of different humidity, gas concentration, flow field turbulence intensity, inert gas mixing, initial pressure and temperature. The opening and closing of the ignition electrode (i.e., regulating the discharge time and duration) is achieved by the synchronous controller 24 and the program control and data acquisition system 25.

[0008] The gas supply system is composed of gas cylinder sources 22-3, 22-4, 22-5, 22-6, a premixing tank 34, a vacuum pressure gauge 20-4 and pipelines. A vacuum pressure gauge 20-4 is installed on the top of the premixing tank 34 to measure the premixed gas pressure inside it. The gas supply system can be used to configure natural gas mixtures with different hydrogen concentrations, and adjust the hydrogen ratio of methane and the concentration of inert gas. In particular, different oxygen contents are added to study the combustion and explosion characteristics and minimum ignition concentration of hydrogen-added natural gas under different oxygen index conditions, the combustion and explosion characteristics and minimum ignition concentration of different hydrogen ratios, and the explosion suppression effect.

[0009] The powder spray explosion suppression system is composed of dust nozzles 19-1 and 19-2, a powder spray tank 23, a vacuum pressure gauge 20-2, a gas cylinder 22-2, a pneumatic two-phase valve, a synchronous controller 24, a program control and data acquisition system 25 and pipelines. The dust nozzles 19-1 and 19-2 are installed on the right inner wall below the container end cover flange 2-1, and are connected to the pneumatic two-phase valve and the powder spray tank 23 through pipelines and ball valves. The powder spray position and the length of the powder spray area can be regulated. The gas cylinder 22-2 provides air source power for the powder spray tank 23, thereby adjusting the powder spray pressure. The vacuum pressure gauge 20-2 measures the powder spray pressure inside the powder spray tank. The pneumatic two-phase valve is connected to the data acquisition system 25 through the synchronous controller 24 and program control to achieve the regulation of the powder spray time and duration.

[0010] The pressure spray system is composed of a spray device 16, a water tank 21, a gas cylinder 22-1, a vacuum pressure gauge 20-1, a solenoid valve, a ball valve, a one-way valve and a pipeline. The spray device 16 is installed on the inner wall of the container end cover flange 2-1 through a threaded connection, and is connected to the ball valve, the one-way valve, the solenoid valve and the water tank 21 in sequence through a pipeline. The vacuum pressure gauge 20-1 measures the internal pressure of the water tank 21, and adjusts the internal pressure of the water tank 21 through the gas cylinder 22-1 to adjust the spray pressure of the spray device 16. The solenoid valve is connected to the data acquisition system 25 through a synchronous controller 24 and program control to achieve the regulation of the spray time and duration. Different numbers of fine atomizing nozzles are installed on the upper end of the spray device to achieve the regulation of the spray working conditions (spray concentration, particle size and water mist speed, etc.). The water tank 21 is configured with aqueous solutions of different additives (including additives with physical and chemical effects) to achieve the study of the influence of different types, concentrations and multi-type ratios of additives on the explosion suppression effect.

[0011] The explosion-proof system is composed of four metal support rods 18 and a flame arrester 4. The four metal support rods 18 are threaded, inserted into the through holes at the corners of the flame arrester 4 and fixed by nuts at the top and bottom. The four metal support rods 18 are at the same height as the visual explosion container 1 and are pressed by the upper and lower container end cover flanges 2-1 and 2-2. The upper and lower pressure plates of the flame arrester are designed and processed according to the cross-sectional area of ​​the visual explosion container 1, and the gap between the upper and lower pressure plates and the wall is blocked with vacuum sealing mud to prevent the flame from passing through and igniting the premixed gas at the upper end. The position height of the flame arrester is adjusted by adjusting the position of the nut. The flame arrester can adopt a porous medium, a wire mesh structure and a corrugated pipe flame arrester structure. Here, the influence of the type of flame arrester and the structural parameters of the flame arrester (porosity, thickness of the flame arrester unit, material, etc.) on the fire-proof effect can be realized.

[0012] The obstacle system is composed of an obstacle 5 and four metal support rods 18. The obstacle 5 has a through hole near the end edge, and is fixed by nuts after passing through the metal support rods 18. The function of the obstacle is to change the flame front structure during the explosion process. By changing the structural parameters (shape, number, position, blocking ratio, etc.) of the obstacle, the flame propagation speed entering the flame arrester is regulated, and the flame arresting effect of the flame arrester structural parameters on different flame propagation speeds is studied.

[0013] The image acquisition system is composed of a high-speed camera 26, a synchronous controller 24 and a program control and data acquisition system 25. The high-speed camera acquisition system is used to collect images of the evolution and propagation process of the closed / open explosion flame morphology inside the visualization explosion container 1. The flame morphology evolution process of the hydrogen-blended natural gas explosion flame under the action of explosion prevention, explosion suppression and their synergy, especially the flame propagation speed entering the front end of the flame arrester, the front flow field under the action of the flame arrester and the flame structure change characteristics after passing through the flame arrester, is crucial for accurately establishing the critical flame arrester speed and clarifying the re-ignition mechanism at the rear end of the flame arrester, as well as establishing a physical model of the flame arrester explosion prevention process. At the same time, the transient evolution characteristics and extinguishing process of the hydrogen-blended natural gas explosion flame after being acted upon by the inhibitor are recorded.

[0014] The Schlieren acquisition system is composed of a high-speed camera 26, a Schlieren instrument 28, a synchronous controller 24, and a program control and data acquisition system 25. The Schlieren acquisition system is used to collect the evolution and development process of the microstructure of the explosion flow field inside and outside the visualization explosion container 1 under the combustion, explosion prevention, explosion suppression and synergistic effect of hydrogen-blended natural gas. In particular, the microstructure change process of the explosion flow field when the flame enters the front end of the flame arrester and passes through the rear end of the flame arrester, as well as the microstructure development and change characteristics of the explosion flow field under the action of the explosion suppressant.

[0015] The oil bath heating / cooling system is composed of an oil bath / cooling jacket 35 and a circulating heating / cooling pump 36. The circulating heating / cooling pump 36 controls the oil bath temperature inside the oil bath / cooling jacket 35, thereby changing the ambient temperature of the premixed gas inside the premixing tank 34, and regulating the initial explosion temperature (including high and low temperatures) of the gas entering the visual explosion container 1, so as to realize the combustion, explosion resistance, explosion suppression and synergistic characteristics of hydrogen-blended natural gas at different ambient temperatures.

[0016] The flow field control system is composed of a micro axial flow fan 7, an axial end sealing device 8, a variable frequency micro motor 9 and a variable frequency power regulator 10-1. The micro axial flow fan 7 is installed in the central area of ​​the container end cover flange 2-2, and the variable frequency micro motor 9 provides power for the micro axial flow fan 7. The two are sealed by the axial end sealing device 8. The rotation of the micro axial flow fan 7 causes the flow of the flow field inside the visualized explosion container 1. The variable frequency power regulator 10-1 adjusts the power of the variable frequency micro motor 9, thereby realizing the change of the turbulence intensity of the flow field inside the visualized explosion container 1.

[0017] The pressure acquisition system is composed of high-frequency pressure sensors 13-1 to 13-4, a synchronous controller 24 and a program control and data acquisition system 25. The high-frequency pressure sensor 13-1 is installed on the left container wall at the upper end of the dust nozzle 19-1 to collect the pressure change process of the flame after the explosion suppressant acts on it. High-frequency pressure sensors 13-2 and 13-3 are respectively installed on the left wall near the upper and lower ends of the flame arrester 4 to collect the transient pressure change process before and after the explosion. The high-frequency pressure sensor 13-4 is installed just above the explosion-proof membrane 39 to collect the pressure distribution changes after the flame passes through the explosion-proof membrane under the end explosion prevention / suppression and coordinated explosion suppression.

[0018] The temperature acquisition system is composed of high-frequency temperature thermocouples 12-1 to 12-4, a synchronous controller 24 and a program control and data acquisition system 25. The high-frequency temperature thermocouple 12-1 is installed on the left container wall at the upper end of the dust nozzle 19-1 to collect the temperature change of the flame inside the visualization explosion container 1 after being suppressed by the explosion suppressant. The high-frequency temperature thermocouples 12-2 and 12-3 are respectively installed on the left wall near the upper and lower ends of the flame arrester 4 to collect the local transient temperature change process before and after the explosion. The high-frequency temperature thermocouple 12-4 is installed just above the explosion-proof membrane 39 to collect the local temperature distribution changes after the flame passes through the explosion-proof membrane under the end explosion prevention / suppression and coordinated explosion suppression. At the same time, combined with the high-frequency infrared thermal imager 29, the distribution change characteristics of the temperature field inside / outside the visualization explosion container 1 during the explosion process under combustion, explosion prevention, explosion suppression and coordinated action are collected.

[0019] The ion detection system is composed of ion detectors 14-1 to 14-4, a signal converter 27, a synchronous controller 24 and a program control and data acquisition system 25. The ion detector 14-1 is installed on the left container wall at the upper end of the dust nozzle 19-1 to collect the changes in ion concentration after the flame inside the visual explosion container 1 is suppressed by the explosion suppressant. The ion detectors 14-2 and 14-3 are respectively installed on the left wall near the upper and lower ends of the flame arrester 4 to collect the transient ion concentration changes before and after the explosion. The ion detector 14-4 is installed just above the explosion-proof membrane 39 to collect the changes in ion concentration distribution after the flame passes through the explosion-proof membrane under the end explosion prevention / suppression and coordinated explosion suppression. The signal converter 27 converts the ion signal into an electrical signal and transmits it to the synchronous controller 24 and the program control and data acquisition system 25 for storage.

[0020] The humidity control system is composed of an atomizing sealed container 37, an ultrasonic atomizer 38, a variable frequency power regulator 10-2, a humidity sensor 15, a humidity display 33, a pipeline and a ball valve. The humidity of the gas in the local space flow field of the ignition electrode 6 in the visual explosion container 1 is regulated, and the influence of environmental humidity on the combustion and explosion characteristics and ignition conditions of hydrogen-blended natural gas is studied. The ultrasonic atomizer 38 in the atomizing sealed container 37 atomizes the water mist and merges it into the air inlet pipe through a branch pipe. The lower end branch pipe is installed on the container end cover flange 2-2 through a threaded connection to achieve the balance of the pressure inside the atomizing sealed container 37 after the water mist enters the inside of the visual explosion container 1. The variable frequency power regulator 10-2 realizes the opening and closing of the ultrasonic atomizer 38 and regulates the atomization speed. The humidity sensor 15 is installed above the air inlet of the visual explosion container 1 to detect the environmental humidity of the gas inside the visual explosion container 1 and display it on the humidity display 33.

[0021] The program control and data acquisition system 25 is written in C language and combined with the synchronous controller 24, it can realize the sequence of ignition, explosion suppressant spraying, water mist spraying, data acquisition and the corresponding moments and times.

[0022] By realizing the correlation and comprehensive analysis of the combustion and explosion characteristics of hydrogen-blended natural gas and explosion parameters (explosion pressure, pressure rise rate, flame temperature, explosion flame propagation characteristics, flow field microstructure, flame ion radical changes, minimum ignition energy, etc.) in a visual experimental device, the coupling process and transient evolution process of multiple physical fields such as pressure field, temperature field, velocity field, density field, etc. are clarified, and by changing the initial conditions and operating parameters, the combustion and explosion characteristics of hydrogen-blended natural gas under the influence of multiple factors and their influencing laws and mechanisms are studied.

[0023] It can realize the study of explosion-proof characteristics of two working conditions: inside a closed container and under the open end, and can realize the study of explosion-proof characteristics of hydrogen-blended natural gas explosion flame and influencing factors and mechanisms. In particular, the influence of flame arrester structural parameters (porosity, flame arrester unit thickness, type) and boundary conditions (hydrogen blending ratio, ignition position, ignition energy, initial pressure, initial temperature) on the flame arrester explosion-proof characteristic parameters. It realizes the study of the influence of flame arrester explosion-proof characteristics and key parameters, and establishes a calculation model for explosion-proof characteristic parameters under the influence of multiple factors; it realizes the process and transient change characteristics of the coupling of multiple physical fields such as the internal flow field (pressure field, temperature field, velocity field, density field) of the flame arrester. In particular, the processes of fluid flow state transformation, flow and heat transfer, shock wave attenuation when high-temperature flame enters the flame arrester, and the influencing mechanism of the coupling effect of flame and shock wave inside the flame arrester are studied. A quantitative relationship between the structural parameters of the flame arrester and the flame propagation velocity and shock wave pressure under the influence of multiple factors is established, and an optimization method for the flame arrester structure is proposed. At the same time, a critical criterion model for deflagration and detonation prevention and the re-ignition mechanism at the back end of the flame arrester are established, thereby providing a theoretical basis and technical support for the development of hydrogen explosion protection theory and the research and development of key flame arrester technologies.

[0024] The explosion suppression characteristics of two working conditions, inside a closed container and outside an open space at the end, can be studied. By spraying powder explosion suppressants along the pipeline and the open end of the container, the explosion flame of hydrogen-blended natural gas can be effectively suppressed, and the evolution characteristics and influencing factors of explosion suppression parameters and flame propagation dynamics can be clarified. By changing the working conditions and explosion suppression parameters, the explosion suppression characteristics of powder explosion suppressants under the influence of multiple parameters and the influence rules and mechanisms of their key parameters can be studied, and explosion suppression criteria can be proposed. At the same time, the explosion flame can be suppressed by spraying fine water mist. The explosion suppression characteristics of hydrogen-blended natural gas can be effectively studied by changing the water mist characteristic parameters.

[0025] The explosion suppression characteristics of hydrogen-blended natural gas under the synergistic effect of explosion prevention and suppression can be studied. By changing the working conditions and explosion prevention / suppression parameters, the explosion suppression characteristics of hydrogen-blended natural gas under the synergistic effect of explosion prevention and suppression under the influence of multiple parameters and the influence rules and mechanisms of key parameters can be studied. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the test device for the combustion and explosion characteristics of hydrogen-blended natural gas and the explosion prevention / suppression synergistic effect under the influence of multiple parameters;

[0027] Figure 2 Ignition electrode physical object and connection diagram;

[0028] Figure 3 Water mist particle size diagram corresponding to different nozzle models;

[0029] Figure 4 Diagram of different types of flame arrester units;

[0030] Figure 5 Flame propagation characteristics of hydrogen-mixed natural gas explosion under the action of corrugated flame arrester;

[0031] Figure 6 Curve diagram showing the effect of different rotation speeds on the flame propagation speed of gas explosion;

[0032] Figure 7 Explosion pressure curves at the upper and lower ends of the flame arrester;

[0033] Figure 8 Flame temperature variation curve at the upper and lower ends of the flame arrester;

[0034] Fig. 9 Curve diagram showing the effect of ambient humidity on the explosion pressure of premixed gas;

[0035] Fig.10 Schematic diagram of end explosion prevention / suppression test conditions.

[0036] In the figure: 1. Visual explosion container; 2-1, 2-2 container end cover flange; 3. Visual window; 4. Flame arrester; 5. Obstacle; 6. Ignition electrode; 7. Micro axial flow fan; 8. Shaft end sealing device; 9. Variable frequency micro motor; 10-1, 10-2 variable frequency power regulator; 11. Container bracket; 12-1~12-4 high frequency temperature thermocouple; 13-1~13-4 high frequency pressure sensor; 14-1~14-4, ion detector; 15, humidity sensor; 16, spray device; 17, exhaust valve; 18, metal support rod; 19-1, 19-2, dust nozzle; 20-1~20-4, vacuum pressure gauge; 21, water storage tank; 22-1~22-6 gas cylinder; 23, powder spray tank; 24, synchronous controller; 25, program control and data acquisition system; 26, high-speed camera; 27, signal converter; 28, schlieren; 29, high-frequency infrared thermal imager; 30, compressor; 31, vacuum pump; 32, adjustable high-pressure igniter; 33, humidity display; 34, premix tank; 35, oil bath / cooling jacket; 36, circulating heating / cooling pump; 37, atomizing closed container; 38, ultrasonic atomizer; 39, explosion-proof membrane; 40, end-face explosion-proof flange. DETAILED DESCRIPTION

[0037] The specific embodiments of the invention are described in detail below in conjunction with the accompanying drawings; this embodiment is applicable to a test device for the combustion and explosion characteristics and explosion suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters and its performance detection technology and method, and its device diagram is as follows Figure 1 As shown, including:

[0038] Visual explosion system, ignition system, air supply system, powder spray explosion suppression system, pressure spray system, explosion-proof system, obstacle system, image acquisition system, schlieren acquisition system, oil bath heating / cooling system, flow field control system, pressure acquisition system, temperature acquisition system, ion detection system, humidity control system, synchronous control system, program control and data acquisition system.

[0039] The visualization explosion system is divided into two structural forms: closed and open. Under the closed structure: the visualization explosion system consists of a visualization explosion container 1, container end cover flanges 2-1, 2-2, a visualization window 3 and an exhaust valve 17, and is sealed by bolt connection. The visualization explosion container 1 is a vertical rectangular structure, and visualization windows 3 are installed in front and behind it to observe the flame propagation dynamics characteristics and flow field microstructure evolution process under the combustion, explosion prevention, explosion suppression and synergistic effect of hydrogen-blended natural gas. In particular, the precise flame propagation speed and morphological evolution process when entering the flame arrester, the flame propagation characteristics and re-ignition development process at the rear end of the flame arrester, the microstructural evolution process of the reverse propagation of the pressure wave under the action of the flame arrester, and the morphological evolution of the explosion flame and the change characteristics of the flow field microstructure under the action of the explosion suppressant. Under the open structure: the visualization explosion system consists of a visualization explosion container 1, a visualization window 3, an explosion relief membrane 39, a container end cover flange 2-2 and an end face explosion relief flange 40. The membrane breaking strength can be adjusted by changing the thickness, number of layers and material of the explosion relief membrane 39; the explosion relief area can be adjusted by changing the opening size of the end face explosion relief flange 40. The exhaust valve 17 is installed on the upper right wall of the visual explosion container 1 to discharge the explosion products. The vacuum pressure gauge 20-3 measures the internal pressure of the visual explosion container 1, is connected to it through a pipeline, and a ball valve is installed between the two for protection. The ball valve is connected to the left side of the vacuum pressure gauge 20-3 and is connected in parallel with the compressor 30 and the vacuum pump 31 respectively. The initial pressure (overpressure) at the time of detonation is regulated by the compressor 30; at the same time, the explosion products inside the visual explosion container 1 can also be purged to achieve the replacement of fresh air from the outside with the products inside the container. The initial pressure (vacuum degree) at the time of detonation inside the visual explosion container 1 is regulated by the vacuum pump 31.

[0040] The ignition system is composed of an ignition electrode 6, an adjustable high-voltage igniter 32, a synchronous controller 24 and a program control and data acquisition system 25. The ignition of the hydrogen-doped natural gas premix is ​​achieved by high-voltage arc discharge. The ignition electrode 6 is installed on the lower part of the left and right walls of the visual explosion container 1 by threading and is 100 mm high from the container end cover flange 2-2. Figure 2As shown. The ignition energy is controlled by an adjustable high-voltage igniter 32, the influence of the ignition energy on the explosion parameters and flame propagation characteristics of hydrogen-blended natural gas is studied, and the minimum ignition energy of hydrogen-blended natural gas under different working conditions is determined; including the influence of different humidity, gas concentration, flow field turbulence intensity, inert gas mixing, initial pressure and temperature, etc. The opening and closing of the ignition electrode (i.e., regulating the discharge time and duration) is realized by a synchronous controller 24 and a program control and data acquisition system 25.

[0041] The gas supply system is composed of gas cylinder sources 22-3, 22-4, 22-5, 22-6, a premixing tank 34, a vacuum pressure gauge 20-4 and pipelines. A vacuum pressure gauge 20-4 is installed on the top of the premixing tank 34 to measure the premixed gas pressure inside it. Through the gas supply system and based on Dalton's law of partial pressure, natural gas mixtures with different hydrogen concentrations can be configured to adjust the hydrogen ratio of methane and the concentration of inert gas. In particular, different oxygen contents are added to study the combustion and explosion characteristics and minimum ignition concentration of hydrogen-added natural gas under different oxygen index conditions, the combustion and explosion characteristics and minimum ignition concentration of different hydrogen ratios, and the explosion suppression effect.

[0042] The powder spray explosion suppression system is composed of dust spray heads 19-1 and 19-2, a powder spray tank 23, a vacuum pressure gauge 20-2, a gas cylinder 22-2, a pneumatic two-phase valve, a synchronous controller 24, a program control and data acquisition system 25 and pipelines. The dust spray heads 19-1 and 19-2 are installed on the right inner wall below the flange 2-1 of the container end cover, and are connected to the pneumatic two-phase valve and the powder spray tank 23 through pipelines and ball valves. The powder spray position and the length of the powder spray area can be regulated. The gas cylinder 22-2 provides air source power for the powder spray tank 23, thereby adjusting the powder spray pressure. The vacuum pressure gauge 20-2 measures the powder spray pressure inside the powder spray tank. The pneumatic two-phase valve is connected to the data acquisition system (25) through the synchronous controller (24) and the program control to achieve the regulation of the powder spray time and duration.

[0043] The pressure spray system consists of a spray device 16, a water tank 21, a gas cylinder 22-1, a vacuum pressure gauge 20-1, a solenoid valve, a ball valve, a one-way valve and a pipeline. The spray device 16 is installed on the inner wall surface of the container end cover flange 2-1 through a threaded connection, and is connected to the ball valve, the one-way valve, the solenoid valve and the water tank 21 in sequence through pipelines. The vacuum pressure gauge 20-1 measures the internal pressure of the water tank 21, and adjusts the internal pressure of the water tank 21 through the gas cylinder 22-1 to adjust the spray pressure of the spray device 16. The solenoid valve is connected to the data acquisition system 25 through the synchronous controller 24 and the program control to realize the regulation of the spray time and duration. Different numbers of fine atomizing nozzles are installed on the upper end of the spray device to realize the regulation of the spray conditions (spray concentration, particle size and water mist speed, etc.), such as Figure 3The water storage tank 21 is provided with aqueous solutions of different additives (including additives with physical and chemical effects) to study the effects of different additive types, concentrations and multiple ratios on explosion suppression effects.

[0044] The explosion-proof system is composed of four metal support rods 18 and a flame arrester 4. The four metal support rods 18 are threaded, inserted into the through holes at the corners of the flame arrester 4 and fixed by nuts at the top and bottom. The four metal support rods 18 are at the same height as the visual explosion container 1 and are pressed by the upper and lower container end cover flanges 2-1 and 2-2. In the open state, the four metal support rods 18 are pressed by the end face explosion relief flange 40. The upper and lower pressure plates of the flame arrester are designed and processed according to the cross-sectional area of ​​the visual explosion container 1, and the gap between the upper and lower pressure plates and the wall is blocked with vacuum sealing mud to prevent the flame from passing through and igniting the premixed gas at the upper end. The position height of the flame arrester is adjusted by adjusting the position of the nut. The flame arrester can adopt a porous medium, a wire mesh structure and a corrugated pipe flame arrester structure. Here, the influence of the type of flame arrester and the structural parameters of the flame arrester (porosity, thickness of the flame arrester unit, material, etc.) on the fire-proof effect can be realized, such as Figure 4 At the same time, there is an obvious corresponding relationship between the critical flame arrester speed and the structural parameters of the flame arrester, as shown in formulas 1 and 2.

[0045] (1)

[0046] (2)

[0047] Where: V c is the critical fire arrest speed; P c is the critical fire arrest pressure; α is the flame arrester porosity; H is the thickness of the fire barrier unit.

[0048] The obstacle system is composed of an obstacle 5 and four metal support rods 18. The obstacle 5 has a through hole near the end edge, and after passing through the metal support rod 18, it is fixed by nuts. The role of the obstacle is to change the flame front structure during the explosion process. By changing the structural parameters of the obstacle (shape, number, position, blocking ratio, etc.), the corresponding relationship between the obstacle structural parameters and the flame propagation speed entering the flame arrester is established. As shown in Formula 3. The flame propagation speed entering the flame arrester is regulated, and then the flame arresting effect of the flame arrester structural parameters on different flame propagation speeds is studied.

[0049] (3)

[0050] Where: Vr The speed of flame propagation into the flame arrester; φ is the obstacle shape coefficient; n is the number of obstacles;l is the distance between the obstacle and the flame arrester; ε is the obstacle blocking ratio.

[0051] The image acquisition system is composed of a high-speed camera 26, a synchronous controller 24 and a program control and data acquisition system 25. The high-speed camera acquisition system is used to collect images of the evolution and propagation of the closed / open explosion flame morphology inside the visualization explosion container 1, such as Figure 5 As shown. The flame morphology evolution process of hydrogen-blended natural gas explosion flame under the action of explosion prevention, explosion suppression and their synergy, especially the flame propagation speed entering the front end of the flame arrester, the front flow field under the action of the flame arrester and the flame structure change characteristics after passing through the flame arrester, is crucial for accurately establishing the critical flame arrester speed and clarifying the re-ignition mechanism at the rear end of the flame arrester, as well as establishing the physical model of the flame arrester explosion prevention process. See formulas 4 and 5. At the same time, the transient evolution characteristics and extinguishing process of the hydrogen-blended natural gas explosion flame after being acted upon by the inhibitor are recorded.

[0052] (4)

[0053] (5)

[0054] Where: V f The speed of flame propagation into the flame arrester; P f The flame arresting pressure entering the flame arrester; C 0 is the combustible gas concentration; E 0 It is the ignition energy; P 0 is the initial pressure.

[0055] The Schlieren acquisition system is composed of a high-speed camera 26, a Schlieren instrument 28, a synchronous controller 24, and a program control and data acquisition system 25. The Schlieren acquisition system is used to collect the evolution and development process of the microstructure of the explosion flow field inside and outside the visualization explosion container 1 under the combustion, explosion prevention, explosion suppression and synergistic effect of hydrogen-blended natural gas. In particular, the microstructure change process of the explosion flow field when the flame enters the front end of the flame arrester and passes through the rear end of the flame arrester, as well as the microstructure development and change characteristics of the explosion flow field under the action of the explosion suppressant.

[0056] The oil bath heating / cooling system is composed of an oil bath / cooling jacket 35 and a circulating heating / cooling pump 36. The oil bath temperature inside the oil bath / cooling jacket 35 is controlled by the circulating heating / cooling pump 36, so that regulation and change can be achieved under low and high temperature environments, thereby changing the ambient temperature of the premixed gas inside the premixing tank 34, regulating the initial explosion temperature (including high and low temperatures) of the gas entering the visual explosion container 1, and realizing the combustion, explosion resistance, explosion suppression and synergistic characteristics of hydrogen-blended natural gas at different ambient temperatures.

[0057] The flow field control system is composed of a micro axial flow fan 7, an axial end sealing device 8, a variable frequency micro motor 9, and a variable frequency power regulator 10-1. The micro axial flow fan 7 is installed in the central area of ​​the container end cover flange 2-2, and the variable frequency micro motor 9 provides power for the micro axial flow fan 7. The two are sealed by the axial end sealing device 8. The rotation of the micro axial flow fan 7 causes the flow of the flow field inside the visualized explosion container 1. It mainly changes the turbulence intensity of the flow field inside the container. The turbulence intensity has a great influence on the propagation characteristics of the combustible gas explosion flame and the explosion parameters. The variable frequency power regulator 10-1 adjusts the power of the variable frequency micro motor 9, thereby realizing the change of the turbulence intensity of the flow field inside the visualized explosion container 1. Figure 6 The effect of different rotation speeds on the flame propagation speed of gas explosion.

[0058] The pressure acquisition system is composed of high-frequency pressure sensors 13-1 to 13-4, a synchronous controller 24 and a program control and data acquisition system 25. The high-frequency pressure sensor 13-1 is installed on the left container wall at the upper end of the dust nozzle 19-1 to collect the pressure change process of the flame after the explosion suppressant acts on it. The high-frequency pressure sensors 13-2 and 13-3 are respectively installed on the left wall near the upper and lower ends of the flame arrester 4 to collect the transient pressure change process before and after the explosion, such as Figure 7 As shown. Through the change of pressure curve, the suppression effect and mechanism of flame arrester on hydrogen-doped natural gas are analyzed. High-frequency pressure sensor 13-4 is installed just above explosion-proof membrane 39 to collect the pressure distribution change after the flame passes through the explosion-proof membrane under end explosion prevention / suppression and coordinated explosion suppression.

[0059] The temperature acquisition system is composed of high-frequency temperature thermocouples 12-1 to 12-4, a synchronous controller 24 and a program control and data acquisition system 25. The high-frequency temperature thermocouple 12-1 is installed on the container wall on the left side of the upper end of the dust nozzle 19-1 to collect the temperature change of the internal flame of the visualization explosion container 1 after being suppressed by the explosion suppressant. The high-frequency temperature thermocouples 12-2 and 12-3 are respectively installed on the left side wall near the upper and lower ends of the flame arrester 4 to collect the local transient temperature change process before and after the explosion. Figure 8The flame temperature change curves at the upper and lower ends of the flame arrester. The heat absorption and cooling effect of the flame arrester on the explosion flame is analyzed by the change law of the flame temperature. The high-frequency temperature thermocouple 12-4 is installed just above the explosion venting membrane 39 to collect the local temperature distribution changes after the flame passes through the explosion venting membrane under the end explosion prevention / suppression and coordinated explosion suppression. At the same time, combined with the high-frequency infrared thermal imager 29, the distribution change characteristics of the temperature field inside and outside the explosion container 1 under the effects of combustion, explosion prevention, explosion suppression and coordinated explosion are collected and visualized.

[0060] The ion detection system is composed of ion detectors 14-1 to 14-4, a signal converter 27, a synchronous controller 24 and a program control and data acquisition system 25. The ion detector 14-1 is installed on the left container wall at the upper end of the dust nozzle 19-1 to collect the changes in ion concentration after the flame inside the visual explosion container 1 is suppressed by the explosion suppressant. The ion detectors 14-2 and 14-3 are respectively installed on the left wall near the upper and lower ends of the flame arrester 4 to collect the transient ion concentration changes before and after the explosion. The ion detector 14-4 is installed just above the explosion-proof membrane 39 to collect the changes in ion concentration distribution after the flame passes through the explosion-proof membrane under the end explosion prevention / suppression and coordinated explosion suppression. The signal converter 27 converts the ion signal into an electrical signal and transmits it to the synchronous controller 24 and the program control and data acquisition system 25 for storage.

[0061] The humidity control system is composed of an atomizing sealed container 37, an ultrasonic atomizer 38, a variable frequency power regulator 10-2, a humidity sensor 15, a humidity display 33, a pipeline and a ball valve. The humidity of the gas in the local space flow field of the ignition electrode 6 in the visual explosion container 1 is controlled, and the influence of the ambient humidity on the combustion and explosion characteristics and ignition conditions of hydrogen-blended natural gas is studied. Fig. 9 As shown. The ultrasonic atomizer 38 in the atomizing sealed container 37 atomizes water mist into the air inlet pipe through the upper branch pipe, and the lower branch pipe is installed on the container end cover flange 2-2 through a threaded connection, so that the water mist enters the visual explosion container 1 and the pressure inside the atomizing sealed container 37 is balanced. The variable frequency power regulator 10-2 realizes the opening and closing of the ultrasonic atomizer 38 and regulates the atomization speed. The humidity sensor 15 is installed above the air inlet of the visual explosion container 1 to detect the ambient humidity of the gas inside the visual explosion container 1 and display it on the humidity display 33.

[0062] The program control and data acquisition system 25 is written in C language, and combined with the synchronous controller 24, it can realize the sequence of ignition, explosion suppressant spraying, water mist spraying, data acquisition and the corresponding moments and times. Under open working conditions, it can realize single explosion suppression, suppression and their synergistic suppression effects, see Fig.10As shown. Condition 1 is simple end explosion suppression, that is, only the flame arrester is used to suppress the end explosion, and neither water mist nor dust is sprayed; Condition 2 is end water mist explosion suppression, that is, spraying fine water mist to suppress the explosion flame; Condition 3 is end powder spraying explosion suppression, spraying inert dust on the outside of the container to suppress the explosion flame; Condition 4 is spraying powder explosion suppressant on the side wall of the container, that is, powder explosion suppression inside the container, and the powder spraying position and explosion suppression zone length can be adjusted according to experimental requirements; Conditions 5 and 6 are synergistic explosion suppression. In Condition 5, when the flame arrester is present, fine water mist is sprayed on the outside of the container, and powder explosion suppressant is sprayed inside the container to achieve synergistic suppression; Under Condition 6, fine water mist and inert dust are sprayed from the outside of the container, and synergistic suppression is achieved with the flame arrester.

[0063] Based on the main functions of the device of the present invention, experimental research on the combustion and explosion dynamics characteristics, explosion prevention, explosion suppression and their synergistic effects of hydrogen-doped natural gas under the influence of multiple parameters can be realized. (1) Factors affecting the combustion and explosion characteristics, including: hydrogen doping ratio, hydrogen-doped natural gas concentration, inert gas concentration, oxygen index, turbulence intensity, initial temperature, initial pressure, humidity, ignition energy, obstacle parameters (shape, size, position, number, spacing and blocking ratio, etc.); (2) Factors affecting the explosion characteristics, including: flame arrester type (corrugated flame arrester, wire mesh flame arrester, foam ceramic flame arrester), flame arrester unit characteristics (corrugated flame arrester: porosity, flame arrester unit thickness, corrugation height and angle; wire mesh flame arrester: material, number of layers, mesh size, etc.; foam ceramic flame arrester: porosity, flame arrester medium thickness, etc.), flame arrester installation position, etc., as well as the factors affecting the combustion and explosion characteristics in (1). (3) Factors affecting explosion suppression characteristics, including: ① Powder explosion suppressants include types of explosion suppressants, dust concentration, powder particle size, explosion suppressant type ratio, powder spraying pressure, powder spraying gas type (air or inert gas), powder spraying position, etc. ② Water mist explosion suppressants include water mist particle size, water mist volume, water mist velocity, additive type, additive concentration, additive ratio, spraying time and duration, etc., as well as factors affecting the explosion characteristics mentioned in (1). (4) Factors affecting the synergistic explosion suppression characteristics, including: the synergistic suppression effect of closed and open spaces, and including the factors affecting the explosion, explosion suppression and explosion suppression characteristics mentioned in (1), (2) and (3).

[0064] Experimental and performance testing technical process:

[0065] (1) Experimental device inspection: Check whether the experimental device is well connected and working properly. Start the program control and data acquisition system 25 and check whether the high-frequency pressure sensor, high-frequency temperature thermocouple, ion detector, ignition electrode, solenoid valve and other devices are operating normally.

[0066] (2) Adjust the image acquisition system: fix the position of the high-speed camera 26 and the high-frequency infrared thermal imager 29, adjust the shooting angle, and ensure that the required image is presented in the shooting area. Adjust the aperture and focal length to obtain the best shooting clarity and set the acquisition parameters, test whether the synchronous controller 24 is working properly, and adjust the Schlieren instrument 28 to the appropriate position.

[0067] (3) Adjusting the ignition system: The ignition energy is adjusted by the adjustable high-voltage igniter 32. The high-voltage discharge is turned on and off by the program control and data acquisition system 25 and the synchronous controller 24.

[0068] (4) Adjusting the program control system: Setting the corresponding startup control program in the program control and data acquisition system 25, determining the parameter settings such as data acquisition, powder spraying time, ignition duration, etc.; adjusting the synchronization controller 24 to make each system execute synchronously.

[0069] (5) Premixed gas configuration: Before the premixed gas is distributed, the visual explosion container 1 is first evacuated to a certain vacuum degree by the vacuum pump 31. Then, the gas cylinders 22-3~22-6 are filled with a certain concentration of premixed gas into the premix tank 34, and enter the visual explosion container 1 through the pipeline. The initial pressure (overpressure or vacuum degree) inside the visual explosion container 1 during detonation is then regulated by the compressor 30 and the vacuum pump 31. The oil bath temperature inside the oil bath / cooling jacket 35 is controlled by the circulating heating / cooling pump 36 to change the ambient temperature of the premixed gas inside the premix tank 34, thereby achieving the regulation of the explosion ambient temperature of the combustible medium. Water vapor is generated by the ultrasonic atomizer 38 in the atomizing closed container 37. The water vapor enters the visual explosion container 1 through the pipeline along with the premixed gas in the premix tank, and the gas humidity at the air inlet is measured by the humidity sensor 15. Then, the humidity of the premixed gas is regulated by adjusting the atomization speed of the ultrasonic atomizer 38 by the variable frequency power regulator 10-2.

[0070] (6) Flow field control: The power of the variable frequency micro motor 9 is controlled by the variable frequency power regulator 10 - 1 , and the variable frequency micro motor 9 drives the micro axial flow fan 7 to rotate, generating radial wind field disturbances to visualize the flow field inside the explosion container 1 .

[0071] (7) The program control and data acquisition system 25 and the synchronous controller 24 control the powder spraying, spraying, ignition, image and data acquisition and storage.

[0072] (8) After the experiment is completed, the explosion products inside the experimental device should be purged and cleaned.

[0073] The beneficial effects of the present invention are:

[0074] (1) The present invention can realize the visualization of the explosion dynamics characteristics of hydrogen-blended natural gas inside / outside the explosion container and the influence rules and mechanism testing research of its explosion characteristic parameters, and the key technology research of the performance testing of the dynamics characteristics of hydrogen-blended natural gas explosion flame and its influence mechanism under multi-parameter working conditions.

[0075] (2) The present invention can combine the explosion prevention, explosion suppression and their synergistic effects to conduct mechanism analysis on the coupling process of multiple physical fields such as pressure field, temperature field, density field, velocity field inside and outside the container, and can more accurately, intuitively and deeply obtain the dynamic characteristics of hydrogen-blended natural gas explosion suppression, explosion prevention and their synergistic effects and the influence mechanism of multiple parameters on their coupling process.

[0076] (3) The present invention can realize the research of multi-parameter, multi-condition explosion prevention / suppression and their synergistic effects. Through the visual synchronous control system, the transient transformation correlation between explosion parameters and flame propagation under different suppression conditions can be realized, which can further reveal and describe the mechanism of explosion prevention and suppression.

[0077] (4) Compared with traditional experimental devices, the present invention has the characteristics of novel design scheme and diverse experimental content, namely, multiple variable parameters, good visualization effect, and intuitive display of experimental results, which can provide theoretical guidance and technical support for the explosion safety protection design of petrochemical enterprises.

[0078] (5) The present invention has a reasonable structure, stable performance, and is easy to operate, making it convenient to carry out performance testing of explosion-proof and explosion-suppressing devices and their coordinated devices on explosion-related containers and pipelines in industrial and trade enterprises, as well as research on influencing factors and mechanisms.

Claims

1. Test device for the combustion and explosion characteristics of hydrogen-blended natural gas and the synergistic effect of explosion prevention / suppression under the influence of multiple parameters, the device includes: Visual explosion system, ignition system, air supply system, powder spray explosion suppression system, pressure spray system, explosion prevention system, obstacle system, image acquisition system, schlieren acquisition system, oil bath heating / cooling system, flow field control system, pressure acquisition system, temperature acquisition system, ion detection system, humidity control system, synchronous control system, program control and data acquisition system; The program control and data acquisition system is combined with a synchronous controller, and is respectively connected with the ignition system, the powder spray explosion suppression system, the pressure spray system, the image acquisition system, the schlieren acquisition system, the pressure acquisition system, the temperature acquisition system, and the ion detection system; The visualization explosion system is divided into two structural forms: closed and open. In the closed structure, the visualization explosion system is composed of a visualization explosion container (1), a first container end cover flange (2-1), a second container end cover flange (2-2) and a visualization window (3). The visualization explosion container (1) is a vertical rectangular structure, and the upper and lower ends of the visualization explosion container are respectively fixed with the first container end cover flange (2-1) and the second container end cover flange (2-2) by bolts to achieve sealing. The visualization windows (3) are installed at the front and rear to observe the combustion, explosion resistance, explosion suppression and flame propagation dynamics characteristics and flow field microstructure evolution process under the synergistic effect of hydrogen-blended natural gas. In the opening structure: the visualization explosion system is composed of a visualization explosion container (1), a visualization window (3), an explosion relief membrane (39), a second container end cover flange (2-2) and an end face explosion relief flange (40); the visualization explosion container (1) is a vertical rectangular structure, the lower end of which is fixed to the second container end cover flange (2-2) by bolts, and the upper end of which is fixed to the end face explosion relief flange (40) by bolts; the explosion relief membrane (39) is arranged on the end face explosion relief flange (40); the membrane breaking strength is adjusted by changing the thickness, number of layers and material of the explosion relief membrane (39); the explosion relief area is adjusted by changing the opening size of the end face explosion relief flange (40); The visual explosion system further comprises: an exhaust valve (17), a third vacuum pressure gauge (20-3), a compressor (30) and a vacuum pump (31); wherein the exhaust valve (17) is installed on the upper right wall of the visual explosion container (1) to discharge the explosion products; the compressor (30) and the vacuum pump (31) are respectively connected to the third vacuum pressure gauge (20-3) through a ball valve and a pipeline, and the third vacuum pressure gauge (20-3) is further connected to the lower left wall of the visual explosion container (1) through a ball valve and a pipeline; The explosion-proof system is composed of four metal support rods (18) and a flame arrester (4); the four metal support rods (18) are threaded, inserted into the through holes at the corners of the flame arrester (4) and fixed by nuts at the top and bottom; the four metal support rods (18) are at the same height as the visual explosion container (1) and are pressed by the upper and lower container end cover flanges; in the open state, the four metal support rods (18) are pressed by the end face explosion relief flange (40); the upper and lower pressure plates of the flame arrester are designed and processed according to the cross-sectional area of ​​the visual explosion container (1), and the gap between the upper and lower pressure plates and the wall surface is blocked by vacuum sealing mud, and the position height of the flame arrester is adjusted by adjusting the position of the nut; the influence of the type of flame arrester, the structural parameters of the flame arrester, i.e., the porosity, the thickness of the flame arrester unit, and the material on the flame arrester effect is studied, and the corresponding relationship between the critical flame arrester speed and the structural parameters of the flame arrester exists, as shown in formulas (1) and (2): （1） （2） Where: V c is the critical fire arrest speed; P c is the critical fire arrest pressure; α is the flame arrester porosity; H is the thickness of the fire barrier unit; The obstacle system is composed of an obstacle (5) and four metal support rods (18); a through hole is opened near the end edge of the obstacle (5), and after passing through the metal support rods (18), nuts are used to press and fix them up and down; the function of the obstacle is to change the flame front structure during the explosion process, and by changing the structural parameters of the obstacle, namely the shape, number, position, and blocking ratio, a corresponding relationship between the obstacle structural parameters and the flame propagation speed entering the flame arrester is established; as shown in formula (3); the flame propagation speed entering the flame arrester is regulated, and then the flame arresting effect of the flame arrester structural parameters on different flame propagation speeds is studied; （3） Where: Vr The speed of flame propagation into the flame arrester; φ is the obstacle shape coefficient; n is the number of obstacles; l is the distance between the obstacle and the flame arrester; ε is the obstacle blocking ratio; The image acquisition system is composed of a high-speed camera (26), a synchronous controller (24) and a program control and data acquisition system (25); the high-speed camera acquisition system is used to acquire images of the evolution and propagation process of the closed / open explosion flame inside the visualization explosion container (1), the flame morphology evolution process of the hydrogen-blended natural gas explosion flame under the action of explosion prevention, explosion suppression and their synergistic effects, the flame propagation speed entering the front end of the flame arrester, the front flow field under the action of the flame arrester and the flame structure change characteristics after passing through the flame arrester, which is crucial for accurately establishing the critical flame arrester speed and clarifying the re-ignition mechanism at the rear end of the flame arrester, as well as establishing a physical model of the flame arrester explosion prevention process; see formulas (4) and (5): （4） （5） Where: V f The speed of flame propagation into the flame arrester; P f The flame arresting pressure entering the flame arrester; C 0 is the combustible gas concentration; E 0 It is the ignition energy; P 0 is the initial pressure; The powder spray explosion suppression system comprises a first dust spray head (19-1), a second dust spray head (19-2), a powder spray tank (23), a second vacuum pressure gauge (20-2), a second gas cylinder (22-2), a pneumatic two-phase valve, a synchronous controller (24), a program control and data acquisition system (25) and a pipeline; the first dust spray head (19-1) and the second dust spray head (19-2) are installed on the right inner wall below the end cover flange (2-1) of the first container, and are connected to the pneumatic two-phase valve through the pipeline and the ball valve. The valve is connected to the powder spraying can (23); the powder spraying position and the length of the powder spraying area are regulated; the second gas cylinder (22-2) is connected to the powder spraying can (23) through a pipeline and a ball valve, and provides gas source power for the powder spraying can (23), thereby adjusting the powder spraying pressure; the second vacuum pressure gauge (20-2) is arranged on the powder spraying can (23) to measure the powder spraying pressure inside the powder spraying can; the pneumatic two-phase valve is connected to the data acquisition system (25) through a synchronous controller (24) and program control, thereby achieving the regulation of the powder spraying time and duration; The pressure spray system comprises a spray device (16), a water storage tank (21), a first gas cylinder (22-1), a first vacuum pressure gauge (20-1), a solenoid valve, a ball valve, a one-way valve and a pipeline; the spray device (16) is installed on the inner wall surface of the first container end cover flange (2-1) through a threaded connection, and is connected to the ball valve, the one-way valve, the solenoid valve and the water storage tank (21) in sequence through a pipeline; the first vacuum pressure gauge (20-1) is arranged on the water storage tank (21) and is used to measure the internal pressure of the water storage tank (21); the first gas cylinder (22-1) is connected to the water storage tank (21) through a pipeline and a ball valve. The spray device (16) is connected to a water tank (21), and the internal pressure of the water tank (21) is adjusted through the first gas cylinder (22-1) to thereby adjust the spray pressure of the spray device (16); the electromagnetic valve is connected to the data acquisition system (25) through a synchronous controller (24) and program control to achieve regulation of the spraying time and duration; different numbers of fine atomizing nozzles are installed on the upper end of the spray device to achieve regulation of the spraying conditions, i.e., spray concentration, particle size and water mist speed; aqueous solutions of different additives are configured inside the water tank (21) to achieve research on the influence of different additive types, concentrations and multi-type ratios on the explosion suppression effect.

2. The test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 1, characterized in that: The ignition system is composed of an ignition electrode (6), an adjustable high-voltage igniter (32), a synchronous controller (24) and a program control and data acquisition system (25); the ignition of the hydrogen-doped natural gas premix is ​​achieved by high-voltage arc discharge; the ignition electrode (6) is installed on the lower part of the left and right walls of the visual explosion container (1) through threads, the ignition energy is controlled by the adjustable high-voltage igniter (32), and the ignition electrode is turned on and off by the synchronous controller (24) and the program control and data acquisition system (25), that is, the discharge time and duration are regulated; The gas supply system comprises a third gas cylinder (22-3), a fourth gas cylinder (22-4), a fifth gas cylinder (22-5), a sixth gas cylinder (22-6), a premixing tank (34), a fourth vacuum pressure gauge (20-4) and pipelines; the fourth vacuum pressure gauge (20-4) is installed on the top of the premixing tank (34) to measure the premixed gas pressure inside the premixing tank (34); the third gas cylinder (22-3), the fourth gas cylinder (22-4), the fifth gas cylinder (22-5) and the sixth gas cylinder (22-6) are respectively connected to the premixing tank (34) through pipelines and ball valves; and natural gas mixtures with different hydrogen concentrations are configured through the gas supply system based on Dalton's law of partial pressure.

3. The test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 2, characterized in that: The schlieren acquisition system is composed of a high-speed camera (26), a schlieren instrument (28), a synchronous controller (24), and a program control and data acquisition system (25); the schlieren acquisition system is used to collect the evolution and development process of the microstructure of the explosion flow field inside and outside the visual explosion container (1) under the combustion, explosion resistance, explosion suppression and synergistic effect of hydrogen-blended natural gas; The oil bath heating / cooling system is composed of an oil bath / cooling jacket (35) and a circulating heating / cooling pump (36); the oil bath temperature inside the oil bath / cooling jacket (35) is controlled by the circulating heating / cooling pump (36) to achieve regulation and change under low and high temperature environments, thereby changing the ambient temperature of the premixed gas inside the premixing tank (34), regulating the initial explosion temperature of the gas entering the visual explosion container (1), and realizing the study of the combustion, explosion resistance, explosion suppression and synergistic characteristics of hydrogen-blended natural gas under different ambient temperatures.

4. The test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 3, characterized in that: The flow field control system is composed of a micro axial flow fan (7), an axial end sealing device (8), a variable frequency micro motor (9) and a first variable frequency power regulator (10-1); the micro axial flow fan (7) is installed in the central area of ​​the second container end cover flange (2-2); the variable frequency micro motor (9) provides power for the micro axial flow fan (7), and the two are sealed and connected via the axial end sealing device (8), and the rotation of the micro axial flow fan (7) causes the flow of the internal flow field of the visualized explosion container (1); the turbulence intensity of the flow field inside the container is changed, and the first variable frequency power regulator (10-1) adjusts the power of the variable frequency micro motor (9), thereby realizing the change of the turbulence intensity of the internal flow field of the visualized explosion container (1).

5. The test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 4, characterized in that: The pressure acquisition system is composed of a first high-frequency pressure sensor (13-1), a second high-frequency pressure sensor (13-2), a third high-frequency pressure sensor (13-3), a fourth high-frequency pressure sensor (13-4), a synchronous controller (24) and a program control and data acquisition system (25); the first high-frequency pressure sensor (13-1) is installed on the left container wall at the upper end of the first dust nozzle (19-1) to collect the pressure change process of the flame after the flame is acted upon by the explosion suppressant; the second high-frequency pressure sensor (13-2) and the third high-frequency pressure sensor (13-3) are respectively installed on the left wall near the upper and lower ends of the flame arrester (4) to collect the transient pressure change process before and after the explosion; the fourth high-frequency pressure sensor (13-4) is installed directly above the explosion-proof membrane (39) to collect the pressure distribution change after the flame passes through the explosion-proof membrane under the end explosion prevention / suppression and coordinated explosion suppression.

6. The test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 5, characterized in that: The temperature acquisition system is composed of a first high-frequency temperature thermocouple (12-1), a second high-frequency temperature thermocouple (12-2), a third high-frequency temperature thermocouple (12-3), a fourth high-frequency temperature thermocouple (12-4), a synchronous controller (24) and a program control and data acquisition system (25); the first high-frequency temperature thermocouple (12-1) is installed on the left container wall at the upper end of the first dust nozzle (19-1) to collect temperature changes of the internal flame of the visualization explosion container (1) after being suppressed by the explosion suppressant; the second high-frequency temperature thermocouple (12-2) and the third high-frequency temperature thermocouple (12-3) are installed on the left container wall at the upper end of the first dust nozzle (19-1) to collect temperature changes of the internal flame of the visualization explosion container (1) after being suppressed by the explosion suppressant; the second high-frequency temperature thermocouple (12-2) and the third high-frequency temperature thermocouple (12-4) are installed on the left container wall at the upper end of the first dust nozzle (19-1) to collect temperature changes of the internal flame of the visualization explosion container (1) after being suppressed by the explosion suppressant; the -3) are respectively installed on the left wall surface near the upper and lower ends of the flame arrester (4) to collect the local transient temperature change process before and after the explosion, and analyze the heat absorption and cooling effect of the flame arrester on the explosion flame through the flame temperature change law; the fourth high-frequency temperature thermocouple (12-4) is installed just above the explosion-proof membrane (39) to collect the local temperature distribution changes after the flame passes through the explosion-proof membrane under the end explosion prevention / suppression and coordinated explosion suppression; at the same time, combined with the high-frequency infrared thermal imager (29), the distribution change characteristics of the temperature field inside / outside the explosion container (1) during the explosion process under the action of combustion, explosion prevention, explosion suppression and coordinated action are collected and visualized.

7. The test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 6, characterized in that: The ion detection system comprises a first ion detector (14-1), a second ion detector (14-2), a third ion detector (14-3), a fourth ion detector (14-4), a signal converter (27), a synchronous controller (24) and a program control and data acquisition system (25); the first ion detector (14-1) is installed on the left container wall surface at the upper end of the first dust nozzle (19-1) to collect the change in ion concentration of the flame inside the visual explosion container (1) after being suppressed by the explosion suppressant; the second ion detector (14-2) and the third ion detector (14-3) are respectively installed on the left wall surface near the upper and lower ends of the flame arrester (4) to collect the transient ion concentration change before and after the explosion prevention; the fourth ion detector (14-4) is installed directly above the explosion relief membrane (39) to collect the change in ion concentration distribution after the flame passes through the explosion relief membrane under the end explosion prevention / suppression and coordinated explosion suppression; the signal converter (27) converts the ion signal into an electrical signal and transmits it to the synchronous controller (24) and the program control and data acquisition system (25) for storage.

8. The test device for the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 7, characterized in that: The humidity control system is composed of an atomizing sealed container (37), an ultrasonic atomizer (38), a second variable frequency power regulator (10-2), a humidity sensor (15), a humidity display (33), a pipeline and a ball valve; the humidity control system is used to realize the control of the gas humidity in the local space flow field of the ignition electrode (6) in the visual explosion container (1), and then study the influence of environmental humidity on the combustion and explosion characteristics and ignition conditions of hydrogen-blended natural gas; the ultrasonic atomizer (38) in the atomizing sealed container (37) generates atomized water mist through the upper end branch pipe and flows into the The air inlet pipe and the lower branch pipe are installed on the second container end cover flange (2-2) through threaded connection to achieve the balance of pressure between the water mist entering the visual explosion container (1) and the internal pressure of the atomization closed container (37); the second variable frequency power regulator (10-2) realizes the opening and closing of the ultrasonic atomizer (38) and regulates the atomization speed; the humidity sensor (15) is installed above the air inlet of the visual explosion container (1) to detect the environmental humidity of the gas inside the visual explosion container (1) and display it on the humidity display (33).

9. A method for conducting an experiment using the test device for the combustion and explosion characteristics of hydrogen-blended natural gas and the explosion prevention / suppression synergistic effect under the influence of multiple parameters as claimed in claim 8, characterized in that: The experimental steps are as follows: (1) Experimental device inspection: Check whether the experimental device is well connected and working properly; start the program control and data acquisition system (25) and check whether the high-frequency pressure sensor, high-frequency temperature thermocouple, ion detector, ignition electrode and solenoid valve device are operating normally; (2) Adjusting the image acquisition system: fixing the positions of the high-speed camera (26) and the high-frequency infrared thermal imager (29), adjusting the shooting angle, and ensuring that the desired image is presented within the shooting area; obtaining the best shooting clarity and setting the acquisition parameters by adjusting the aperture and focal length, testing whether the synchronization controller (24) is working properly, and adjusting the schlieren (28) to an appropriate position; (3) Adjusting the ignition system: adjusting the ignition energy through the adjustable high-voltage igniter (32); realizing the opening and closing of the high-voltage discharge through the program control and data acquisition system (25) and the synchronous controller (24); (4) Adjusting the program control system: Setting the corresponding startup control program in the program control and data acquisition system (25) to determine the parameter settings for data acquisition, powder spraying time, and ignition duration; and adjusting the synchronization controller (24) to synchronize the execution of each system.

10. The method for testing the combustion and explosion characteristics and explosion prevention / suppression synergistic effect of hydrogen-blended natural gas under the influence of multiple parameters according to claim 9, characterized in that: The experimental steps also include: (5) Premixed gas configuration: Before premixing the gas, the visual explosion container (1) is first evacuated to a certain vacuum degree by a vacuum pump (31), and then the third gas cylinder (22-3), the fourth gas cylinder (22-4), the fifth gas cylinder (22-5), and the sixth gas cylinder (22-6) are filled with a predetermined concentration of premixed gas into the premix tank (34), and the premixed gas enters the visual explosion container (1) through a pipeline; the initial pressure inside the visual explosion container (1) is then regulated by a compressor (30) and a vacuum pump (31) during detonation; and the circulating heating / cooling pump (36) is used to heat the visual explosion container (1) and cool the visual explosion container (1) to a certain concentration. The temperature of the oil bath inside the oil bath / cooling jacket (35) is controlled to change the ambient temperature of the premixed gas inside the premixing tank (34) to achieve the regulation of the explosion ambient temperature of the combustible medium; water vapor is generated by an ultrasonic atomizer (38) in an atomizing closed container (37), and the water vapor enters the visual explosion container (1) through a pipeline along with the premixed gas in the premixing tank, and the gas humidity at the air inlet is measured by a humidity sensor (15), and then the atomization speed of the ultrasonic atomizer (38) is adjusted by a second variable frequency power regulator (10-2) to adjust the humidity of the premixed gas; (6) Flow field control: the power of the variable frequency micro motor (9) is controlled by the first variable frequency power regulator (10-1), and the variable frequency micro motor (9) drives the micro axial flow fan (7) to rotate, thereby generating radial wind field disturbances to visualize the flow field inside the explosion container (1); (7) Controlling powder spraying, spraying, ignition, image and data collection and storage through a program control and data acquisition system (25) and a synchronous controller (24); (8) After the experiment is completed, the explosion products inside the experimental device should be purged and cleaned.

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