Modular Visual Experimental Apparatus and Methods for Studying the Explosion Characteristics and Protection of Hydrogen-Methane Mixed Fuels

Abstract

This invention discloses a modular, visualized experimental apparatus and method for studying the explosion characteristics and protection of hydrogen-methane mixed fuels. The apparatus includes a visualized experimental channel, a real-time automatic gas distribution system, a synchronous controller, an igniter, a high-speed camera system, and a sensor network and data acquisition system. This experimental apparatus constructs a comprehensive experimental platform integrating visualization and multi-channel synchronous operation through the aforementioned systems. It can systematically acquire explosion propagation characteristic data of hydrogen-methane mixed fuels under different hydrogen blending ratios and equivalence ratios on the same experimental platform. It features visualization, scalability, repeatability, safety protection, and multi-dimensional synchronous acquisition. It can collect key data such as transient pressure waves, flame propagation morphology, and dynamic characteristics during the explosion process, and based on this, reveal the coupling mechanism of flame propagation and pressure waves, and verify / depressurize optimization and explosion suppression / explosion-proof protection schemes.

Description

Technical Field

[0001] This invention relates to the field of experimental testing technology for safety and protection against combustible gas explosions, specifically to a modular and visualized experimental apparatus and method for studying the explosion characteristics and protection of hydrogen-methane mixed fuels, and in particular, a modular and visualized experimental apparatus and its control method for studying the explosion propagation, pressure relief, and explosion suppression / blocking mechanisms of hydrogen / methane / air premixed gas. Background Technology

[0002] Hydrogen energy, as a highly efficient and clean secondary energy source, is gradually becoming an important supporting component of the energy system. Large-scale transportation of hydrogen produced by electrolyzing renewable resources such as wind and solar power through existing natural gas pipeline networks can significantly reduce hydrogen transportation costs and contribute to achieving carbon neutrality. While natural gas pipeline safety assessment technology is relatively mature, the addition of hydrogen alters the physical properties and combustion characteristics of the gas, increasing the probability of pipeline failure and its consequences. The added hydrogen increases flame velocity, potentially leading to violent combustion or even explosions. The hazards primarily manifest as combustion and explosions in completely confined spaces, partially confined spaces, and open spaces, as well as high-speed jet flames generated by rapid pipeline leaks. Under varying hydrogen blending ratios and equivalence ratios, the explosion intensity, flame morphology, and pressure wave evolution of the mixed fuels exhibit significant differences.

[0003] Currently, experimental research on the explosion process of fuels such as hydrogen and methane, both domestically and internationally, mainly relies on two types of platforms: one is a sealed steel tank or cylindrical explosion container, suitable for measuring high-pressure combustion and pressure wave propagation in confined spaces; the other is a large-scale semi-open test field, used to simulate the explosion propagation characteristics in hydrogen refueling stations, vehicle cabins, or building spaces. The former has certain advantages in obtaining pressure parameters, but due to the limited metal enclosure structure, the flame propagation process and flow field evolution are difficult to observe intuitively, making it difficult to support the simultaneous analysis of the "flame propagation-pressure wave" coupling mechanism; the latter, although closer to actual engineering conditions, usually suffers from high experimental costs, high risks, high requirements for organization and protection, difficulty in data acquisition, and insufficient repeatability, making it difficult to meet the needs of parameter scanning and mechanism comparison studies.

[0004] Furthermore, existing experimental platforms mostly employ fixed-scale metal containers or single-structure channels, making it difficult to quickly reconstruct geometric boundaries, obstacle configurations, and pressure relief conditions. Interface specifications and installation methods lack unified standards, hindering the coordinated arrangement and reliable sealing of multiple sensors. Insufficient triggering and synchronization capabilities for high-speed imaging and multi-channel pressure / temperature / concentration signal acquisition result in temporal deviations and a lack of spatial correspondence among multi-source data, thus limiting systematic research and model verification of flame propagation-pressure wave coupling mechanisms, pressure relief dynamic responses, and explosion suppression / explosion-proofing strategies within mesoscale channels.

[0005] Therefore, there is an urgent need for an experimental device and method that is structurally reconfigurable, parameter-adjustable, highly visualized, and capable of multi-dimensional synchronous measurement, in order to obtain explosion characteristic data of hydrogen-methane mixed fuel under different hydrogen doping ratios and equivalence ratios, and to verify and optimize protection schemes such as pressure relief and explosion suppression / explosion blocking. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a modular, visualized experimental apparatus and method for studying the explosion characteristics and protection of hydrogen-methane mixed fuels.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, a modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels is provided, including: A visualization experimental channel, comprising multiple transparent pipe segment units, is modularly assembled via a sealed connection. Each transparent pipe segment unit is equipped with a universal interface of uniform specifications. This universal interface is used at least for sensor installation and for the reuse of pressure relief and protection systems. A real-time automatic gas mixing system, which is connected to the visualization experimental channel, is used to measure and mix hydrogen, methane and air online, and supply premixed gas into the visualization experimental channel; A synchronization controller, which is connected to an igniter, a high-speed camera system, and a sensor network and data acquisition system, is used to achieve synchronous start-up of ignition, imaging, and data acquisition under unified trigger signal control; The igniter is connected to the visualization experiment channel via an ignition wire, and the sensor network and data acquisition system are connected to the visualization experiment channel via several cables.

[0008] This experimental device constructs a comprehensive experimental platform integrating visualization and multi-channel synchronous operation through the aforementioned systems. It features visualization, scalability, repeatability, safety protection, and multi-dimensional synchronous acquisition. It can collect key data such as transient pressure waves, flame propagation patterns, and dynamic characteristics during the explosion process, and thereby reveal the coupling mechanism of flame propagation and pressure waves, as well as verify / depressurization optimization and explosion suppression-explosion-proof protection schemes.

[0009] Furthermore, the real-time automatic gas distribution system includes a dynamic gas distribution device connected to the visualization experimental channel, and a hydrogen supply unit, a methane supply unit, and an air supply unit connected to the dynamic gas distribution device. It also includes a concentration detection unit, which is located at the outlet of the real-time automatic gas mixing system and / or the outlet of the visualization experimental channel, for verifying the concentration of the premixed gas.

[0010] Furthermore, the transparent pipe segment unit is made of heat-shock resistant transparent material, and both ends are sealed and connected to the sealing ring through end plates to form a structurally stable sealed cavity; the side wall of the transparent pipe segment unit is provided with multiple universal interfaces, which are standardized threaded interfaces.

[0011] Furthermore, the visualization experimental channel also includes a transition section module, which is used to realize the change of the cross-sectional size or equivalent diameter of the experimental channel.

[0012] Furthermore, the middle of the visualization experimental channel is also equipped with a detachable obstacle module, a perforated plate module, or a filter structure to change the propagation and flow conditions within the experimental channel.

[0013] Furthermore, the pressure relief and protection system includes a replaceable pressure relief module and / or an explosion suppression module and / or an explosion-proof module, and the universal interface selectively mounts the pressure relief module, the explosion suppression module, and the explosion-proof module.

[0014] Furthermore, the sensor network and data acquisition system includes a multi-channel data acquisition module connected to the synchronization controller. The multi-channel data acquisition module is communicatively connected to the host computer. The multi-channel data acquisition module is also connected to a pressure sensor, a flame sensor, and a temperature sensor. The pressure sensor and the flame sensor are used to acquire the transient pressure signal and the flame arrival time signal generated during the explosion, respectively. The temperature sensor is used to record the temperature distribution and flame temperature rise characteristics before and after the explosion.

[0015] Furthermore, the high-speed camera system includes a high-speed camera connected to the synchronization controller. The high-speed camera is equipped with an optical lens and connected to a computer to continuously image the flame propagation process under high resolution and high frame rate conditions, recording the flame propagation morphology and transient structural evolution during the explosion.

[0016] On the other hand, a modular and visual experimental method for studying the explosion characteristics and protection of hydrogen-methane mixed fuels is provided, the experimental method comprising the following steps: Step 1: Construct the visualization experimental channel and complete the airtightness check; Specifically, the experimental platform is built and assembled according to the predetermined experimental content, and the modular cascading and end structure configuration of the visualized experimental pipeline are completed. Before each test, the pressure relief module is reset or replaced (e.g., the PE pressure relief membrane is replaced), and the flange connection, sealing ring and each threaded interface are checked for airtightness to confirm that there is no residual pressure and no residual combustible gas in the pipeline. Pressure sensors and photoelectric flame sensors are installed at the designated measuring points of the pipeline according to the target working conditions, and the sensor wiring, acquisition channels and signal integrity are verified.

[0017] Step 2: Prepare and fill the visualization experimental channel with premixed gas online through the real-time automatic gas mixing system; Specifically, the target mixed fuel component parameters are set through the automatic gas distribution system, including at least the hydrogen gas fraction, methane volume fraction, and total flow rate (or equivalent flow ratio / equivalent ratio parameter). The gas distribution device outputs a stable hydrogen-methane-air premixed gas. The pipeline inlet and outlet valves are opened, and the premixed gas is continuously introduced into the pipeline for replacement. The original air in the pipeline is replaced within a preset ventilation time, and the mixed fuel concentration (or hydrogen gas fraction) at the pipeline outlet is stabilized near the set value. The ventilation time is determined according to the channel length and volume.

[0018] Step 3: Seal the visualization experimental channel and let it stand to allow the premixed gas to homogenize; Specifically, after the gas replacement in the visualization experimental channel is completed, the inlet flow rate is gradually reduced and the inlet and outlet valves are closed, so that the pipeline (transparent pipe section unit) is in a closed state and left to stand for a predetermined time to promote further uniform mixing of the premixed gas; during or after the standing period, the gas concentration detection unit is used to conduct random sampling or online verification at representative locations to confirm that the concentration of the mixed fuel in the pipeline is consistent with the gas distribution set value or the deviation is within the allowable range.

[0019] Step 4: Build the optical environment, perform a pre-test of the synchronization controller, clear the cache and restore the actual acquisition settings after the pre-test is completed; Specifically, before ignition, an optical environment suitable for high-speed imaging is constructed (e.g., by turning off indoor lighting, shading, or setting dark field conditions). Without ignition, the high-speed camera system and data acquisition system are triggered and pre-run through the synchronization controller to check whether the trigger link and timing signals are normal. At the same time, the baseline outputs of the pressure sensor and flame sensor are read to confirm that they are stable and within the normal range under no-ignition conditions. After the pre-run is completed, the cache is cleared and the system is restored to the formal acquisition settings.

[0020] Step 5: Parameter setting and synchronous ignition acquisition. The synchronous controller sends a unified trigger signal to start the igniter, the high-speed camera system, the sensor network and the data acquisition system synchronously. The unified trigger signal and / or the flame sensor signal are used as the time reference to perform time-domain aligned acquisition of flame images and pressure signals. Specifically, the exposure time, frame rate, and acquisition time window of the high-speed camera system are set, the sampling frequency and trigger mode of the data acquisition system are set, and the ignition device is put into standby mode. When the settling time meets the requirements, a unified trigger signal is issued through the synchronization controller to realize the synchronous start-up of the ignition device, the high-speed camera system, and the data acquisition system: the ignition device (igniter) ignites the premixed hydrogen-methane-air fuel mixture in the pipeline at the predetermined ignition position; the high-speed camera system records the image sequence of the flame propagation process; and the data acquisition system synchronously acquires the transient pressure time history, flame sensor photoelectric signal, and trigger signal at each measuring point.

[0021] Step 6: After the experiment, perform a venting procedure and save the experimental data; Specifically, after the explosion process ends and the pressure inside the pipeline is confirmed to have returned to near ambient pressure, the ignition device (igniter) and related power supply system are shut off. The vent valve or exhaust valve is slowly opened to introduce the residual gas into the exhaust gas treatment or ventilation system. Then the valve is closed and the integrity of the device is checked. The image sequence and sensor data of this test are saved and backed up using a high-speed camera system and data acquisition software. These data are used to extract characteristic parameters such as the flame front position, flame propagation speed, peak overpressure, pressure rise rate, and positive pressure duration, and are used to evaluate the effectiveness of the protective measures.

[0022] Furthermore, the criterion for completion of filling is that the concentration of the mixed gas at the outlet of the visualization experimental channel is stable within a set value range.

[0023] Furthermore, step 7 is included: operating condition switching and repeatability assurance; before conducting the next set of operating conditions, the airtightness of the visualization experimental channel and the general interface is checked to ensure that there is no leakage and no residual combustible gas; according to the test plan, the modules of the pressure relief and protection system are replaced, the sensor arrangement and gas distribution parameters are adjusted to complete the operating condition switching, thereby ensuring the comparability and data repeatability between different operating condition tests.

[0024] This experimental method, through a unified operating procedure, structural reset, and parameter configuration, ensures the comparability of test conditions and the repeatability of data between different working conditions. This results in good consistency of the obtained flame propagation characteristics and pressure response parameters, as well as their reliability for model verification. Consequently, it enhances the engineering applicability of this experimental platform in the study of the explosion mechanism of hydrogen-methane mixed fuels, the verification of protection schemes, and the optimization of pressure relief systems.

[0025] Compared with existing technologies, the beneficial effects of this invention are: 1. This experimental device constructs a comprehensive experimental platform integrating visualization and multi-channel synchronous operation, possessing features such as visualization, scalability, repeatability, safety protection, and multi-dimensional synchronous acquisition; it can acquire key data such as transient pressure waves, flame propagation morphology, and dynamic characteristics during the explosion process, and thereby reveal the coupling mechanism of flame propagation and pressure waves, and verify / depressurization optimization and explosion suppression-explosion-proof protection schemes; 2. This experimental device constructs the explosion channel into a modular structure formed by the cascading of multiple transparent pipe segment units, and adopts standardized sealing and connection methods, enabling rapid reconstruction of channel length, end boundaries, and local configurations on the same platform, supporting explosion propagation tests under different geometric and depressurization conditions, significantly improving the efficiency of operating condition switching and structural comparability; 3. By adopting a unified universal interface system, functional components such as sensors, depressurization, and sampling can be configured and replaced under consistent installation methods, achieving standardized integration of measurement and functional modules, reducing the layout limitations and insufficient sealing reliability problems caused by inconsistent interface specifications in traditional devices, and enabling repeated tests under multiple measurement points and multiple operating conditions. 4. The real-time automatic gas mixing system can accurately measure and mix hydrogen, methane, and air online. Combined with displacement filling, closed settling, and concentration verification mechanisms, it ensures good consistency and repeatability of the premixed environment under different hydrogen blending ratios and equivalence ratios, thereby reducing data dispersion caused by ratio fluctuations or insufficient displacement and improving the reliability of comparative analysis between different operating conditions. 5. By using a synchronous controller to integrate the igniter, high-speed imaging system, and multi-channel data acquisition system into a unified trigger and time reference, it achieves precise alignment of flame images and pressure signals on the same time axis, effectively avoiding time-domain deviation and signal mismatch problems caused by asynchronous multi-source data in existing platforms. 6. The experimental method, through a unified operation procedure, structural reset, and parameter configuration, ensures the comparability of experimental conditions and the repeatability of data between different operating conditions. This ensures that the obtained flame propagation characteristics and pressure response parameters have good consistency and reliability for model verification, enhancing the engineering applicability of this experimental platform in the study of hydrogen-methane mixed fuel explosion mechanisms, protection scheme verification, and pressure relief system optimization. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall experimental device for studying the explosion characteristics and protection of hydrogen-methane mixed fuel according to the present invention. Figure 2 This is a schematic diagram of the cross-sectional structure of the transparent pipe segment unit of the present invention; Figure 3 This is a schematic diagram of the T-shaped pipe module in the transparent pipe segment unit of the present invention; Figure 4 This is a schematic diagram of the side structure and explosion vent design of the transparent pipe section unit of the present invention; Figure 5 This is a schematic diagram of a perforated plate of different sizes used in the present invention to study explosion suppression and flame acceleration. Figure 6 This is a schematic diagram of the nozzle in the explosion suppression module of the present invention.

[0027] In the diagram: 1. Host computer; 2. Data acquisition card; 3. Ignition device; 4. High-speed camera; 5. Synchronization controller; 6. Computer; 7. Air compressor; 8. Hydrogen cylinder; 9. Methane cylinder; 10. Dynamic gas distribution device; 11. Explosion vent; 12-14. Pressure sensor; 15. Flame sensor; 16. Transparent pipe section unit; 17. T-shaped pipe module; 18. Perforated plate; 19. Nozzle. Detailed Implementation

[0028] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] Example 1: A modular, visualized experimental device for studying the explosion characteristics and protection of hydrogen-methane mixed fuels is provided, combined with... Figures 1-5 As shown, it includes: A visualization experimental channel includes multiple transparent pipe segment units 16, which are modularly assembled through a sealed connection. Each transparent pipe segment unit 16 is equipped with a universal interface of uniform specifications. The universal interface is used at least for sensor installation and reused installation of pressure relief and protection systems. A real-time automatic gas mixing system, which is connected to the visualization experimental channel, is used to measure and mix hydrogen, methane and air online, and supply premixed gas into the visualization experimental channel; Synchronization controller 5, which is connected to igniter 3, high-speed camera system and sensor network and data acquisition system, is used to realize the synchronous start of ignition, imaging and data acquisition under unified trigger signal control; The igniter 3 is connected to the visualization experiment channel via an ignition wire, and the sensor network and data acquisition system are connected to the visualization experiment channel via several cables.

[0031] This experimental device constructs a comprehensive experimental platform integrating visualization and multi-channel synchronous operation through the aforementioned systems. It features visualization, scalability, repeatability, safety protection, and multi-dimensional synchronous acquisition. It can collect key data such as transient pressure waves, flame propagation patterns, and dynamic characteristics during the explosion process, and thereby reveal the coupling mechanism of flame propagation and pressure waves, as well as verify / depressurization optimization and explosion suppression-explosion-proof protection schemes.

[0032] This experimental setup constructs the explosion channel as a modular structure formed by cascading multiple transparent pipe segment units 16, and employs standardized sealing and connection methods. This allows for rapid reconfiguration of the channel length, end boundaries, and local configuration on the same platform, thereby supporting explosion propagation tests under different geometric and depressurization conditions. This significantly improves the efficiency of operating condition switching and structural comparability, and solves the problem of inflexible adjustment of geometric boundaries and test parameters in existing devices. The transparent pipe segment unit 16 can also be configured as a T-shaped pipe module 17.

[0033] By adopting a unified and universal interface system, functional components such as sensors, pressure relief, and sampling can be configured and replaced under a consistent installation method, realizing the standardized integration of measurement and functional modules. This reduces the layout limitations and insufficient sealing reliability caused by inconsistent interface specifications in traditional devices, and provides a stable and consistent structural foundation for repeated tests under multiple measurement points and multiple operating conditions.

[0034] The real-time automatic gas mixing system can accurately measure and mix hydrogen, methane and air online. Combined with replacement filling, closed settling and concentration verification mechanisms, it can ensure good consistency and repeatability of the premixed environment under different hydrogen doping ratios and equivalence ratios. This reduces data dispersion caused by ratio fluctuations or insufficient replacement and improves the reliability of comparative analysis between different operating conditions.

[0035] By integrating the igniter, high-speed imaging system, and multi-channel data acquisition system into a unified trigger and time reference through a synchronous controller, precise alignment of flame images and pressure signals on the same time axis is achieved. This effectively avoids the time domain deviation and signal mismatch problems caused by the asynchronous nature of multi-source data in existing platforms, and provides a synchronous data foundation for quantitative analysis of the coupling mechanism of flame propagation and pressure wave evolution.

[0036] Preferably, the transparent pipe segment unit 16 of the visualization experimental pipeline is made of a transparent material with high mechanical strength and good thermal shock resistance. The preferred material is high borosilicate glass, which is primarily composed of silicon dioxide with a content in the range of 78-81%, and contains a certain proportion of boron oxides. This gives it a low coefficient of thermal expansion, high chemical stability, and good thermal shock resistance, enabling it to maintain structural stability under transient pressure shocks and thermal loads generated during explosion experiments. Both ends of the transparent pipe segment unit are sealed with stainless steel end plates and high-temperature resistant sealing rings, forming a structurally stable sealed cavity. Multiple transparent pipe segments can be cascaded and combined through stainless steel flange connections between adjacent transparent pipe segment units, thereby constructing visualization explosion channels with different total lengths, boundary conditions, and end shapes. This modular structure allows flame propagation, pressure wave evolution, and depressurization processes to be directly observed and recorded within the transparent channel.

[0037] Each transparent tube section unit 16 has a universal interface of M20×1.5 on its side wall. The interface can be selectively installed with pressure sensor, flame sensor, pressure relief device, blind plug or sampling port according to experimental requirements. The top plate is preferably equipped with a high-frequency pressure sensor mounting hole, and the bottom is equipped with a vent valve or drain valve to meet the requirements of filling, replacement and safe release after the experiment.

[0038] Furthermore, the real-time automatic gas distribution system includes a dynamic gas distribution device 10 connected to the visualization experimental channel, and a hydrogen supply unit, a methane supply unit, and an air supply unit connected to the dynamic gas distribution device 10, for achieving precise proportioning and stable supply of hydrogen, methane, and air.

[0039] In this embodiment, the dynamic gas mixing device 10 is preferably an automatic multi-component dynamic gas mixing device. The automatic multi-component dynamic gas mixing device includes a multi-channel mass flow control unit, a mixing manifold, a pressure stabilizing component, and a control display module, and is connected to the experimental pipeline via a standardized gas path interface. It can simultaneously supply at least hydrogen, air, and a third gas, enabling continuous preparation and dynamic adjustment of multi-component premixed gases.

[0040] Each gas channel preferably adopts the thermal mass flow control principle: after the gas forms a laminar flow through the distributor, it enters the capillary measurement channel. The mass flow signal is obtained by utilizing the heat transfer changes caused by the gas flow. The controller compares the real-time measured value with the set value and realizes real-time tracking of the output flow to the set value through the closed-loop regulating valve, thereby obtaining a stable component ratio and total flow at the outlet.

[0041] Preferably, the total flow rate of the automatic multi-component dynamic gas mixing device is 10 SLM, the control range of each channel is 0% to 80% of the range, the minimum control resolution can reach 0.1%, the gas mixing accuracy is preferably ±0.5%FS, and the repeatability is no greater than ±0.5%FS, thereby significantly reducing the mixing ratio fluctuation between different operating conditions.

[0042] The hydrogen supply unit includes a high-purity hydrogen cylinder 8 and a pressure reducing and stabilizing component connected thereto; the air supply unit includes an air compressor 7 and a corresponding pressure reducing and stabilizing component; and the methane supply unit includes a methane cylinder 9 and a pressure reducing and stabilizing component connected thereto. Hydrogen, methane, and air are all pressure-stabilized before entering the automatic gas distribution device to reduce the impact of upstream pressure fluctuations on the accuracy of mass flow control.

[0043] To ensure the accuracy of the premixed gas volume fraction and the consistency of experimental conditions, the real-time automatic gas mixing system also includes a concentration detection unit. The concentration detection unit is located at the outlet of the real-time automatic gas mixing system and / or the outlet of the visualization experimental channel. It is used to verify the premixed gas concentration and use the detection result as a criterion for gas mixing and replacement effects.

[0044] Furthermore, the visualization experimental channel also includes a transition section module, used to realize changes in the cross-sectional size or equivalent diameter of the experimental channel. For example, a multi-scale connection structure transitioning from 100 mm to 200 mm.

[0045] The visualization experimental channel also includes a detachable obstacle module, a perforated plate module, or a filter structure in the middle to alter the propagation and flow conditions within the channel. The perforated plate module can be a densely packed perforated plate 18 with varying pore sizes. This is used to study the flame refraction, reflection, and turbulence enhancement effects under complex geometric conditions.

[0046] Furthermore, based on the aforementioned modular system, powder spraying units, atomizing nozzles, or flame-retardant mesh modules can be introduced in series within the pipeline to construct various explosion suppression and explosion suppression experimental conditions, including powder explosion suppression, water mist explosion suppression, and multi-level explosion suppression combination structures. Each module can be replaced independently or used in combination, thereby forming a repeatable and comparable multi-level protection experimental platform, providing a reliable experimental basis for the performance evaluation of explosion-proof materials and the optimization of pressure relief structures.

[0047] Furthermore, the pressure relief and protection system includes a replaceable pressure relief module and / or an explosion suppression module and / or an explosion-proof module, and the universal interface selectively mounts the pressure relief module, the explosion suppression module, and the explosion-proof module. The pressure relief module can be configured as a T-shaped, circular, rectangular, or slit-shaped pressure relief port, and its installation position, opening area, and opening pressure are adjustable; the explosion suppression module can be a powder explosion suppression device or a water mist explosion suppression device, and the explosion-proof module can be a flame arrester or a porous structure.

[0048] By replacing the end modules or introducing different types of pressure relief modules into the channels, various flame propagation and pressure relief scenarios can be constructed to study the formation conditions and evolution characteristics of typical explosion flame morphologies such as finger flames, tulip flames, and twisted tulip flames. This structure breaks through the limitations of traditional fixed-geometry explosion devices, enabling the experimental platform to rapidly reconstruct different pressure relief boundaries while maintaining consistent measurement conditions, in order to systematically analyze the coupling relationship between flame morphology and pressure wave evolution.

[0049] Preferably, the explosion suppression module is used to actively suppress flame propagation, pressure increase, and secondary disturbances during the premixed hydrogen-methane-air explosion process. The explosion suppression module includes at least a water mist explosion suppression submodule and a powder explosion suppression submodule, both of which achieve rapid release and spatial dispersion of the medium through nozzle assemblies installed on the pipe / cavity wall, thereby intervening in the flame front and high-temperature reaction zone. The nozzle assembly is a replaceable structure (e.g., ...). Figure 6 The nozzle 19 shown can be detachably connected to the universal interface of the device, thereby realizing the rapid switching between water mist nozzle and powder nozzle; the nozzle assembly and the supply unit are connected through the pipeline assembly. The supply unit can be a combination of liquid storage tank / powder storage tank, pressurized air source, valve group and control unit, which is used to quickly establish the flow and spray of the medium after the trigger signal arrives.

[0050] Furthermore, the sensor network and data acquisition system includes a multi-channel data acquisition module (such as data acquisition card 2) connected to the synchronization controller. The multi-channel data acquisition module is communicatively connected to the host computer 1. The multi-channel data acquisition module is also connected to pressure sensors 12-14 (high-frequency pressure sensors), flame sensors 15, and temperature sensors, as well as a corresponding signal conditioning and communication module. The pressure sensors 12-14 and flame sensors 15 are used to acquire transient pressure signals and flame arrival time signals generated during the explosion, respectively. The temperature sensor is used to record the temperature distribution and flame temperature rise characteristics before and after the explosion.

[0051] Preferably, the multi-channel data acquisition module has a fully electrically isolated structure, and each channel can be configured as a bridge piezoresistive sensor input or a voltage / current input mode. The high-frequency pressure sensor is preferably connected in a full-bridge configuration, with a stable DC excitation provided by the multi-channel data acquisition module. Its output differential voltage signal is amplified, filtered, and converted from analog to digital at the front end for synchronous sampling.

[0052] The multi-channel data acquisition module communicates with the host computer 1 via an Ethernet interface. The host computer is used to configure channel parameters, display in real time, trigger recording, and export data. Through a unified external trigger signal, the ignition system, high-speed camera system, and data acquisition system can be started synchronously, thereby ensuring the consistency of pressure signals and flame images on the time axis.

[0053] The high-frequency pressure sensor is a piezoresistive pressure sensor, which is directly mounted on the wall of a transparent pipe section via a threaded interface. It is used to measure transient pressure changes during an explosion. This type of sensor has a high natural frequency and good dynamic response characteristics, and can effectively capture the rapid rise edge and multiple reflection waveforms of the explosion pressure.

[0054] The flame sensor is a photoelectric flame detector with a response band covering the visible to near-infrared range, capable of rapidly responding to the light radiation signals generated during the combustion of hydrogen-methane mixed fuels. The flame sensor is integrated with a transparent tube section via a standard threaded interface to record the flame arrival time and provide a time reference signal.

[0055] The temperature sensor is a thermocouple array or an infrared temperature measurement module.

[0056] The high-frequency pressure sensor, flame sensor, and high-speed camera system are all connected to the synchronous control system to achieve temporal alignment and comprehensive analysis of flame propagation, light radiation, and pressure wave evolution during the explosion process.

[0057] Furthermore, the igniter 3 is a high-energy igniter, connected to an ignition rod and an ignition wire (cable). The ignition rod is threadedly installed at a designated position on the experimental pipeline to reliably ignite the premixed gas in the pipeline at a predetermined time. The front end of the ignition rod is made of a high-temperature resistant alloy material to withstand the high-temperature environment under explosion conditions.

[0058] The igniter 3 releases ignition energy through an external power supply and control switch. Its output spark energy can be selected according to experimental requirements, thereby ensuring stable ignition under different hydrogen doping ratios and equivalence ratios.

[0059] Furthermore, the high-speed camera system includes a high-speed camera 4 connected to the synchronization controller 5. The high-speed camera 4 is equipped with an optical lens and connected to a computer 6. It continuously images the flame propagation process under high resolution and high frame rate conditions, and supports further improvement of temporal resolution by cropping the imaging area or pixel merging, recording the flame propagation morphology and transient structural evolution during the explosion.

[0060] Preferably, the high-speed camera 4 has an imaging frame rate of not less than 10,000 fps, an exposure time of not more than 5 μs, and can be used with an ultraviolet band filter component to capture the propagation pattern of hydrogen-methane mixed fuel flame.

[0061] Example 2: Taking the static rupture pressure calibration test of PE film as an example, this experimental method is further explained in conjunction with the experimental apparatus in Example 1.

[0062] (1) Install the PE film at the explosion vent 11 of the transparent pipe section unit 16 (that is, the test pipe), adjust the tension of the PE film, and check the sealing of the explosion vent flange connection and each interface of the transparent pipe section unit to confirm that the system is in a state of no obvious leakage; at the same time, confirm that the data acquisition card 2 and the pressure sensors 12-14 are working properly.

[0063] (2) Only air is introduced into the transparent pipe section unit 16 through the intelligent gas distribution device 10. A suitable mass flow rate is set so that air continuously enters the pipe from the inlet end. At the same time, the outlet valve is closed so that the pressure in the pipe increases slowly under the condition of no obvious flow impact, thereby achieving uniform loading of static pressure in the pipe.

[0064] (3) Start the data acquisition card 2 and its supporting data acquisition and analysis software to collect and record the pressure signal in the transparent pipe section unit in real time until the PE film ruptures and the explosion vent 11 is opened, end the test, and record the pressure value corresponding to the moment the film ruptures.

[0065] (4) Repeat the above steps under different vent areas and different specifications of PE film to obtain multiple sets of film rupture pressure data; by comparing and analyzing the pressure curves of each measuring point under static slow pressurization conditions, determine the rupture pressure as the static activation pressure of the vent device for comparison and analysis of subsequent explosion test conditions.

[0066] Example 3: Taking the explosion test of premixed hydrogen-methane-air fuel as an example, this experimental method is further explained in conjunction with the experimental apparatus in Example 1.

[0067] Step 1: Build and assemble the experimental platform according to the test plan. Replace the PE explosion relief membrane before each test and check the flange connection and threaded interface sealing of the transparent pipe section unit 16 to confirm that there is no residual pressure and combustible gas in the pipeline. Arrange pressure sensors 12-14 and flame sensors 15 on the transparent pipe section unit according to the test conditions, and check the sensor wiring and data acquisition channel status.

[0068] Step 2: Set the target hydrogen gas integral number and corresponding flow ratio through the intelligent gas distribution device 10, and output a stable hydrogen-air premixed gas; open the inlet valve and outlet valve of the transparent pipe section unit 16, and use continuous ventilation replacement method to fill the pipeline with premixed gas, complete the replacement of the original air in the pipeline within the predetermined ventilation time, and stabilize the hydrogen gas integral number at the outlet end near the set value.

[0069] Step 3: After the gas replacement is completed, gradually reduce the intake flow rate and close the intake valve and outlet valve to keep the transparent pipe section unit 16 in a closed state and let it stand for a predetermined time to promote further uniform mixing of the premixed gas in the pipeline; during the standing period, representative locations are sampled using mixed fuel component / concentration detection methods to confirm that the gas concentration in the pipeline is close to the gas distribution set value.

[0070] Step 4: After completing the static premixing, construct a dark field environment suitable for high-speed imaging; without starting the igniter 3, perform a synchronous trigger test on the ultra-high-speed camera 4 and data acquisition card 2 through the synchronous controller 5 to check whether the trigger signal is normal, and confirm that the baseline output of the pressure sensors 12-14 and the flame sensor 15 is stable under the condition of no ignition.

[0071] Step 5: Reset the exposure time, frame rate, and acquisition time window parameters of the ultra-high-speed camera 4, and set the sampling frequency and trigger mode of the data acquisition card 2 to put the igniter 3 into standby mode; when the settling time meets the requirements, the trigger command is issued through the synchronization controller 5 to realize the synchronous start of the igniter 3, the ultra-high-speed camera 4, and the data acquisition card 2. The igniter 3 ignites the premixed hydrogen-air in the transparent tube section unit 16 at the predetermined position, the high-speed camera 4 records the flame propagation process image, and the data acquisition card 2 synchronously acquires the pressure signal and flame light signal of each measuring point.

[0072] Step Six: After the explosion process ends and the pressure inside the transparent tube unit 16 is confirmed to have returned to near ambient pressure, shut off the igniter 3 and related power supply system, slowly open the vent or exhaust valve to introduce the residual gas into the ventilation or exhaust gas treatment system, then close the valve and check the integrity of the device; save and back up the image data and sensor data of this test through the ultra-high speed camera 4 and the data acquisition system.

[0073] Step 7: Before conducting the next set of test conditions, check the airtightness of the transparent pipe section unit 16 and each interface to confirm that there is no leakage and residual combustible gas. Replace the explosion relief membrane, adjust the sensor arrangement and gas distribution parameters according to the test plan to ensure the comparability and repeatability of data between different test conditions.

[0074] Example 4: This example is based on the modular visualization hydrogen-methane mixed fuel explosion characteristics and protection research system experimental device described in the previous examples. A hydrogen-methane-air premixed gas with an equivalence ratio of 1 and a hydrogen doping ratio of 20% is selected as the research object, and its explosion propagation characteristics in the visualization experimental channel are experimentally studied.

[0075] (I) Experimental Operating Conditions In this embodiment, the hydrogen doping ratio is defined as the volume fraction of hydrogen in the fuel composition, i.e. ϕH2=VH2 / (VH2+VCH4)=20% ϕH2 is the proportion of hydrogen in the mixed fuel, VH2 is the volume of hydrogen, and VCH4 is the volume of methane.

[0076] The equivalence ratio ER is defined as the ratio of the actual fuel-air ratio to the theoretical stoichiometric fuel-air ratio. In this embodiment, ER is set to 1, corresponding to stoichiometric combustion conditions. Based on the hydrogen blending ratio and the equivalence ratio, the intelligent gas distribution device 10 calculates and sets the volume fraction and flow rate ratio of hydrogen, methane, and air to generate the target hydrogen-methane-air premixed gas composition.

[0077] (II) Construction and preparation of the experimental platform An experimental platform was constructed according to the method described in the aforementioned embodiment. Multiple transparent pipe segment units 16 were modularly cascaded to form a visual experimental channel, and an explosion vent 11 was installed at the end of the channel. Before the test, a new explosion vent diaphragm was replaced, and the flange connections, sealing rings, and various interfaces of the transparent pipe segment units 16 were checked for airtightness to confirm that the system had no leaks and that there was no residual pressure or combustible gas in the pipeline.

[0078] According to the experimental plan, pressure sensors 12-14 and flame sensors 15 were installed at designated positions along the transparent pipe section unit 16, and their connection with the data acquisition card 2 and the synchronous controller 5 was completed and their functions were checked.

[0079] (III) Premixed gas preparation and displacement filling The intelligent gas distribution device 10 sets the mass flow control parameters for hydrogen, methane, and air, allowing them to mix online to form a hydrogen-methane-air premixed gas with an equivalence ratio of 1 and a hydrogen doping ratio of 20%. The inlet and outlet valves of the transparent pipe section unit 16 are opened, and the premixed gas is continuously ventilated to replace the existing air in the pipe within a preset ventilation time.

[0080] During the replacement process, the concentration of the premixed gas is verified by the concentration detection units set at the outlet of the intelligent gas distribution device 10 and the outlet of the transparent pipe section unit 16. When the concentration of the mixed fuel at the outlet of the transparent pipe section unit is stable within the set value allowable deviation range, the replacement is determined to be complete.

[0081] (iv) Preparation for closed-loop static setting and experimental triggering After the replacement is completed, the intake air flow rate is gradually reduced and the intake and exhaust valves are closed, so that the transparent pipe section unit 16 is in a closed state and left to stand for a predetermined time to promote further homogenization of the hydrogen-methane-air premixed gas in the pipeline. After the standing period, the concentration of the mixed gas at representative locations is measured again using the concentration detection unit to confirm that it is consistent with the set operating conditions.

[0082] Subsequently, an optical environment suitable for high-speed imaging was constructed. Without ignition, the igniter 3, the ultra-high-speed camera 4, and the data acquisition card 2 were synchronously triggered and pre-run through the synchronous controller 5 to check the correctness of the trigger link and signal timing, and to confirm that the baseline output of the pressure sensors 12-14 and the flame sensor 15 was stable.

[0083] (v) Synchronous ignition and data acquisition After parameter reset, a unified trigger signal is sent through the synchronization controller 5 to synchronously start the igniter 3, the ultra-high-speed camera 4, and the data acquisition card 2. The igniter 3 ignites the hydrogen-methane-air premixed gas in the pipeline at a designated position in the transparent pipe section unit 16. The ultra-high-speed camera 4 records the propagation morphology and evolution process of the flame in the transparent pipe section unit 16. The data acquisition card 2 synchronously acquires the transient pressure signal and flame arrival time signal at each measuring point, and uses the trigger signal and the flame sensor signal as the time reference to achieve time-domain alignment of multi-source data.

[0084] (vi) End of Experiment and Data Processing After the explosion process ended and the pressure inside the transparent tube unit 16 was confirmed to have returned to near ambient pressure, the igniter 3 and related power supply systems were shut off, and the vent valve was slowly opened to safely release the residual gas inside the transparent tube unit 16. The experimental setup was then inspected to confirm that all components were intact.

[0085] The flame image sequence and pressure data obtained in this experiment were saved and backed up by the ultra-high-speed camera 4 and the data acquisition card 2. These data will be used for subsequent analysis of the flame propagation speed, flame morphology evolution characteristics, peak overpressure and pressure wave propagation law of hydrogen-methane-air premixed gas under the conditions of equivalence ratio of 1 and hydrogen doping ratio of 20%. The data will also provide an experimental data basis for the comparative study of pressure relief and explosion suppression / explosion arrest protection effects.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels, characterized in that, include: A visualization experimental channel, comprising multiple transparent pipe segment units, is modularly assembled via a sealed connection. Each transparent pipe segment unit is equipped with a universal interface of uniform specifications. This universal interface is used at least for sensor installation and for the reuse of pressure relief and protection systems. A real-time automatic gas mixing system, which is connected to the visualization experimental channel, is used to measure and mix hydrogen, methane and air online, and supply premixed gas into the visualization experimental channel; A synchronization controller, which is connected to an igniter, a high-speed camera system, and a sensor network and data acquisition system, is used to achieve synchronous start-up of ignition, imaging, and data acquisition under unified trigger signal control; The igniter is connected to the visualization experiment channel via an ignition wire, and the sensor network and data acquisition system are connected to the visualization experiment channel via several cables.

2. The modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 1, characterized in that, The real-time automatic gas distribution system includes a dynamic gas distribution device connected to the visualization experimental channel, and a hydrogen supply unit, a methane supply unit, and an air supply unit connected to the dynamic gas distribution device. It also includes a concentration detection unit, which is located at the outlet of the real-time automatic gas mixing system and / or the outlet of the visualization experimental channel, for verifying the concentration of the premixed gas.

3. The modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 1, characterized in that, The transparent pipe section unit is made of heat-shock resistant transparent material, and both ends are sealed and connected to the sealing ring through end plates to form a structurally stable sealed cavity; the side wall of the transparent pipe section unit is provided with multiple universal interfaces, which are standardized threaded interfaces.

4. The modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 1, characterized in that, The visualization experimental channel also includes a transition section module, which is used to realize the change of the cross-sectional size or equivalent diameter of the experimental channel.

5. The modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 1, characterized in that, The visualization experimental channel is also equipped with a detachable obstacle module, a perforated plate module, or a filter structure in the middle to change the propagation and flow conditions within the experimental channel.

6. The modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 1, characterized in that, The pressure relief and protection system includes a replaceable pressure relief module and / or an explosion suppression module and / or an explosion-proof module, and the universal interface is used to selectively install the pressure relief module, the explosion suppression module and the explosion-proof module.

7. The modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 1, characterized in that, The sensor network and data acquisition system includes a multi-channel data acquisition module connected to the synchronization controller. The multi-channel data acquisition module is communicatively connected to a host computer. The multi-channel data acquisition module is also connected to a pressure sensor, a flame sensor, and a temperature sensor. The pressure sensor and the flame sensor are used to acquire transient pressure signals and flame arrival time signals generated during the explosion, respectively. The temperature sensor is used to record the temperature distribution and flame temperature rise characteristics before and after the explosion.

8. The modular, visualized experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 1, characterized in that, The high-speed camera system includes a high-speed camera connected to the synchronization controller. The high-speed camera is equipped with an optical lens and connected to a computer. It continuously images the flame propagation process under high resolution and high frame rate conditions, and records the flame propagation morphology and transient structural evolution during the explosion.

9. The experimental method of the modular visualization experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to any one of claims 1 to 8, characterized in that, The experimental method includes the following steps: The visualization experimental channel was constructed and its airtightness was checked. The premixed gas is prepared online and filled into the visual experimental channel through the real-time automatic gas mixing system. The visualization experimental channel was sealed and left to stand to allow the premixed gas to homogenize. Build the optical environment, perform a pre-test of the synchronization controller, clear the cache and restore the actual acquisition settings after the pre-test is completed; The synchronization controller sends a unified trigger signal to synchronously start the igniter, the high-speed camera system, the sensor network, and the data acquisition system, and uses the unified trigger signal and / or the flame sensor signal as a time reference to perform time-domain aligned acquisition of flame images and pressure signals. After the experiment, the wastewater was released and the experimental data was saved.

10. The experimental method of the modular visualization experimental apparatus for studying the explosion characteristics and protection of hydrogen-methane mixed fuels according to claim 9, characterized in that, The criterion for completion of filling is that the concentration of the mixed gas at the outlet of the visualization test channel is stable within a set value range. Before carrying out the next set of working conditions, the airtightness of the visualization test channel and the general interface is checked to ensure that there is no leakage and no residual combustible gas. The pressure relief and protection system modules are replaced, the sensor arrangement and gas distribution parameters are adjusted according to the test plan to complete the working condition switch.

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