Experimental device and method for inhibiting spontaneous combustion of high-pressure hydrogen gas leakage by mixing with ammonia gas

Abstract

This invention discloses an experimental apparatus and method for suppressing spontaneous combustion of high-pressure hydrogen leaks by ammonia blending. It relates to the field of hydrogen leak spontaneous combustion experimental technology. The experimental apparatus includes: a high-pressure hydrogen supply module, an anti-liquefaction ammonia supply module, a staged blending module, and a recording module. The high-pressure hydrogen supply module provides high-pressure hydrogen as a venting gas source; the anti-liquefaction ammonia supply module maintains ammonia in a fully gaseous state before feeding it into the staged blending module; the staged blending module includes a venting guide section and an ammonia blending port circumferentially located at the inlet end of the venting guide section; the inlet end of the venting guide section is connected to the high-pressure hydrogen supply module; the anti-liquefaction ammonia supply module injects ammonia into the boundary of the high-pressure hydrogen jet during venting of high-pressure hydrogen; the recording module records the venting plume, pressure wave, and ignition delay time. This invention enables anti-liquefaction ammonia supply and dynamic boundary layer blending to support research on suppressing spontaneous combustion of high-pressure hydrogen leaks and provides experimental basis for subsequent engineering applications.

Description

Technical Field

[0001] This invention relates to the field of hydrogen leakage spontaneous combustion experimental technology, and in particular to an experimental device and method for suppressing high-pressure hydrogen leakage spontaneous combustion by mixing ammonia. Background Technology

[0002] High-pressure hydrogen is prone to spontaneous combustion during leakage, injection, and mixing with air due to impact compression, localized heating, turbulent entrainment, and increased reactivity. Introducing ammonia into the hydrogen system can raise the spontaneous combustion threshold and suppress spontaneous combustion through dilution, free radical competition, and reaction path modulation. Regarding the flame suppression mechanism of the ammonia / hydrogen system, published literature and patents have discussed issues such as ammonia blending to suppress high-pressure hydrogen spontaneous combustion, ammonia-hydrogen engine injection, and ammonia cracking. However, most schemes are more focused on fuel utilization or numerical mechanism analysis. The experimental setup itself often still uses the conventional combination of a high-pressure gas storage chamber, rupture disc, and downstream pipeline. It can only be used to study pre-mixing schemes, that is, mixing ammonia and hydrogen in a high-pressure container before venting, and then venting through the rupture disc.

[0003] However, in the pre-mixing scheme, ammonia is easily liquefied under high pressure, causing the actual mixing ratio to deviate significantly from the set value and making the metering uncontrollable.

[0004] For the reasons mentioned above, the inventors have proposed a novel technical approach: dynamically incorporating ammonia into the boundary layer of the hydrogen jet after a hydrogen injection or leak. This approach avoids the liquefaction of ammonia due to high-pressure hydrogen compression and more closely approximates actual leak scenarios. However, there is currently no dedicated device or method for experimental research on this "boundary ammonia incorporation" scenario.

[0005] Therefore, there is an urgent need to develop an experimental device and method that can achieve ammonia liquefaction prevention supply, dynamic boundary layer mixing, and multi-parameter synchronous recording, in order to support research on the suppression of spontaneous combustion of high-pressure hydrogen leakage and provide experimental basis for subsequent engineering applications. Summary of the Invention

[0006] The purpose of this invention is to provide an experimental device and method for suppressing spontaneous combustion of high-pressure hydrogen leakage by mixing ammonia gas, so as to solve the problems existing in the prior art. It can realize the supply of ammonia gas to prevent liquefaction, dynamic mixing of the boundary layer, and has the function of synchronous recording of multiple parameters, so as to support the research on suppressing spontaneous combustion of high-pressure hydrogen leakage and provide experimental basis for subsequent engineering applications.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides an experimental device for suppressing spontaneous combustion of high-pressure hydrogen leaks by mixing ammonia, comprising: a high-pressure hydrogen supply module, an anti-liquefaction ammonia supply module, a staged mixing module, and a recording module. The high-pressure hydrogen supply module provides high-pressure hydrogen as a venting gas source; the anti-liquefaction ammonia supply module maintains ammonia in a fully gaseous state before supplying it to the staged mixing module; the staged mixing module includes a venting guide section and an ammonia mixing port circumferentially located at the inlet end of the venting guide section; the inlet end of the venting guide section is connected to the high-pressure hydrogen supply module, and its outlet end is connected to the atmosphere; the anti-liquefaction ammonia supply module is connected to the ammonia mixing port and is used to inject ammonia into the boundary of the high-pressure hydrogen jet during venting of high-pressure hydrogen; the recording module records the venting plume, pressure wave, and ignition delay time.

[0008] In some embodiments, the anti-liquefaction ammonia supply module includes: an ammonia source, a vaporization superheater, a membrane separator, a buffer pressure stabilizing tank, a dew point monitoring chamber, a first mass flow controller, and an electrically controlled valve with a check valve function; The ammonia source, vaporization superheater, membrane separator, buffer pressure stabilizing tank, first mass flow controller, and electric control valve are connected in sequence, and the outlet of the electric control valve is connected to the ammonia mixing port. The liquid outlet of the membrane separator is connected to the ammonia source or a separately installed reflux collection tank via a reflux valve. The dew point monitoring chamber is connected to the outlet of the buffer pressure stabilizing tank via a sampling branch, and is used to continuously extract gas for dew point measurement.

[0009] In some embodiments, the ammonia mixing port is composed of a plurality of injection micro-holes, the diameter of the injection micro-holes being 0.2 mm to 0.5 mm, and the injection direction of the injection micro-holes being inclined downstream along the axial direction of the discharge guide section, or radially inward towards the central axis of the discharge guide section.

[0010] In some embodiments, the high-pressure hydrogen supply module includes: a high-pressure hydrogen source, a pressure reducing valve, a second mass flow controller, and a high-pressure hydrogen main chamber; the high-pressure hydrogen source, the pressure reducing valve, the flow controller, and the high-pressure hydrogen main chamber are connected in sequence; the outlet of the high-pressure hydrogen main chamber is connected to the inlet end of the venting guide section, and a rupture disc is provided between the two.

[0011] In some embodiments, the pipeline upstream of the electrically controlled valve is pre-filled with pressurized ammonia; the electrically controlled valve automatically opens when releasing high-pressure hydrogen, allowing upstream ammonia to be injected into the release guide section through the ammonia mixing port; in the non-release state, the electrically controlled valve remains closed to prevent ammonia from flowing out.

[0012] In some embodiments, a nitrogen purging module is also included, which is connected to the venting guide section via a pipeline and is used to purge and purge the venting guide section.

[0013] In some embodiments, the anti-liquefaction ammonia supply module further includes a control module; the control module is used to collect the temperature of ammonia gas after vaporization and overheating in the anti-liquefaction ammonia supply module, the ammonia gas pressure at the outlet of the buffer pressure stabilizing tank, and the ammonia gas dew point temperature measured by the sampling branch, and to perform closed-loop control of the heating power, reflux valve and nitrogen purging valve according to the above-detected signals; when the ammonia supply side is detected to deviate from the full gas phase window, the module automatically performs reflux, pressure reduction, ammonia supply cut-off and nitrogen purging operations.

[0014] In some embodiments, the side wall of the discharge guide section is provided with a visual observation window; the recording module includes a high-frequency dynamic pressure sensor and a photoelectric probe installed on the wall of the discharge guide section, and a camera system disposed outside the discharge guide section; The response frequency of the high-frequency dynamic pressure sensor is not less than 100kHz; the camera system includes at least one of a schlieren imager, a high-speed camera, and a PLIF measurement system.

[0015] In some embodiments, the discharge guide section is provided with an optical diagnostic interface.

[0016] The present invention also provides a method for inhibiting spontaneous combustion of high-pressure hydrogen gas during leakage using the experimental apparatus described above, comprising the following steps: S1: Activate the anti-liquefaction ammonia supply module to heat the ammonia to a full gas phase state, and detect the temperature, pressure and dew point of the ammonia to ensure that the ammonia meets the preset superheat requirements; S2: Ammonia gas in its entire gas phase is set to the target flow rate through a mass flow controller and pre-charged into the upstream pipeline of the ammonia mixing port; S3: Fill the high-pressure hydrogen supply module with high-pressure hydrogen to the preset pressure; S4: Trigger the rupture disc to release high-pressure hydrogen into the release guide section, while ammonia is injected from the ammonia mixing port into the boundary layer of the high-pressure hydrogen jet. The two mix and then enter the test environment. S5: The recording module synchronously records the venting plume, pressure wave, and ignition delay time to evaluate the inhibitory effect of ammonia on spontaneous combustion of high-pressure hydrogen leaks.

[0017] The present invention achieves the following technical effects compared to the prior art: This invention addresses the issue of ammonia injection by placing the ammonia inlet circumferentially at the inlet end of the venting guide section. This allows ammonia to be dynamically injected from the jet boundary layer during high-pressure hydrogen venting, rather than being pre-mixed with hydrogen within the high-pressure container. This technique avoids ammonia liquefaction due to compression under high pressure, ensuring the actual mixing ratio matches the set value and resolving the issue of uncontrollable metering in pre-mixing schemes. Furthermore, boundary layer ammonia injection more closely resembles the real-world scenario of ammonia being injected or leaked into the hydrogen jet edge from the outside, making the experimental data on spontaneous combustion suppression more valuable for engineering reference. Additionally, by simultaneously collecting plume, pressure wave, and ignition delay time using a recording module, the suppression effect on spontaneous combustion under different ammonia-injected conditions can be systematically evaluated. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; In the diagram: 1-High-pressure hydrogen source; 2-Pressure reducing valve; 3-Hydrogen shut-off valve; 4-Second mass flow controller; 5-High-pressure hydrogen main chamber; 6-Pressure sensor; 7-Ammonia blending port; 8-Visual observation window; 9-Release guide section; 10-Camera system; 11-Nitrogen cylinder; 12-Rupture disc; 13-Photoelectric probe; 14-Ammonia source; 15-Vaporization superheater; 16-Membrane separator; 17-Temperature sensor; 18-Buffer pressure stabilizing tank; 19-Electrically controlled valve; 20-Pressure sensor in the anti-liquefaction ammonia supply module; 21-Pressure stabilizing valve; 22-Reflux collection tank; 23-Dew point monitoring chamber; 24-Control module. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only 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.

[0021] The purpose of this invention is to provide an experimental device and method for suppressing spontaneous combustion of high-pressure hydrogen leakage by mixing ammonia gas, so as to solve the problems existing in the prior art. It can realize the supply of ammonia gas to prevent liquefaction, dynamic mixing of the boundary layer, and has the function of synchronous recording of multiple parameters, so as to support the research on suppressing spontaneous combustion of high-pressure hydrogen leakage and provide experimental basis for subsequent engineering applications.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The following is combined with Figure 1 The following describes embodiments of the present invention.

[0024] Example 1 This invention provides an experimental device for suppressing spontaneous combustion of high-pressure hydrogen leaks by mixing ammonia, comprising: a high-pressure hydrogen supply module, an anti-liquefaction ammonia supply module, a staged mixing module, and a recording module. The high-pressure hydrogen supply module provides high-pressure hydrogen as a venting gas source; the anti-liquefaction ammonia supply module maintains ammonia in a fully gaseous state before supplying it to the staged mixing module; the staged mixing module includes a venting guide section 9 and an ammonia mixing port 7 located circumferentially at the inlet end of the venting guide section 9; the inlet end of the venting guide section 9 is connected to the high-pressure hydrogen supply module, and its outlet end is connected to the atmosphere; the anti-liquefaction ammonia supply module is connected to the ammonia mixing port 7 and is used to inject ammonia into the boundary of the high-pressure hydrogen jet during venting of high-pressure hydrogen; the recording module records the venting plume, pressure wave, and ignition delay time.

[0025] This embodiment places the ammonia inlet 7 circumferentially at the inlet end of the venting guide section 9, allowing ammonia to be dynamically injected from the jet boundary layer during high-pressure hydrogen venting, rather than being pre-mixed with hydrogen within the high-pressure container. This technical solution avoids ammonia liquefaction due to compression under high pressure, ensuring the actual mixing ratio matches the set value and solving the problem of uncontrollable metering in pre-mixing schemes. Furthermore, boundary layer ammonia mixing more closely resembles the real-world scenario of ammonia being injected or leaked into the hydrogen jet edge from the outside in engineering practice, thus providing more valuable data for suppressing spontaneous combustion. In addition, by simultaneously collecting plume, pressure wave, and ignition delay time using the recording module, the suppression effect on spontaneous combustion under different ammonia mixing conditions can be systematically evaluated.

[0026] In some embodiments, the anti-liquefaction ammonia supply module includes: an ammonia source 14, a vaporization superheater 15, a membrane precipitator 16, a buffer pressure stabilizing tank 18, a dew point monitoring chamber 23, a first mass flow controller, and an electrically controlled valve 19 with a check valve function; the ammonia source 14, the vaporization superheater 15, the membrane precipitator 16, the buffer pressure stabilizing tank 18, the first mass flow controller, and the electrically controlled valve 19 are connected in sequence, and the outlet of the electrically controlled valve 19 is connected to the ammonia mixing port 7; the liquid accumulation outlet of the membrane precipitator 16 is connected to the ammonia source 14 or an independently set reflux collection tank 22 through a reflux valve; the dew point monitoring chamber 23 is connected to the outlet of the buffer pressure stabilizing tank 18 through a sampling branch, and is used to continuously extract gas for dew point measurement.

[0027] This embodiment, through the establishment of a multi-stage processing link including a vaporization superheater 15, a membrane precipitator 16, and a dew point monitoring chamber 23, can vaporize liquid ammonia before superheating, ensuring that the ammonia temperature is higher than its pressure-corresponding saturation temperature (i.e., in a fully gaseous state). The membrane precipitator 16 removes any potentially entrained micro-droplets, and the dew point monitoring chamber 23 continuously confirms the gaseous state. Logically, this scheme ensures that the ammonia remains in a stable single-phase gas state before entering the ammonia blending port 7, preventing droplets from entering and causing micropore blockage or unstable spraying. Simultaneously, the buffer pressure stabilizing tank 18 and the pressure stabilizing valve 21 smooth pressure fluctuations, allowing the mass flow controller to accurately control the ammonia flow rate, thus ensuring the repeatability of the target blending ratio. The reflux valve and reflux collection tank 22 can recover condensate, reducing ammonia waste and improving safety.

[0028] Alternatively, the sampling branch of the dew point monitoring chamber 23 can be directly led out from the outlet of the vaporization superheater 15, but the outlet of the buffer pressure tank 18 is more representative of the stable state before entering the mass flow controller. The reflux collection tank 22 can also be omitted, and the condensate can be directly discharged into the exhaust gas treatment system.

[0029] In some embodiments, the vaporization superheater 15 employs an electrically heated microchannel core, and its outlet ammonia temperature is controlled to be more than 20°C higher than the saturation temperature corresponding to the current pressure.

[0030] In some embodiments, the ammonia doping port 7 is composed of multiple injection micro-holes with a diameter of 0.2 mm to 0.5 mm. The injection direction of the injection micro-holes is inclined downstream along the axial direction of the discharge guide section 9, or radially inward towards the central axis of the discharge guide section 9.

[0031] In this embodiment, the injection direction is either axially tilted downstream or radially inward towards the central axis. Logically, this promotes sufficient contact and mixing of the boundary layer between the ammonia jet and the high-pressure hydrogen jet, while preventing ammonia from directly impacting the core region of the hydrogen jet and interfering with the core characteristics of the auto-ignition process. Both directions achieve the function of flame suppression through boundary layer intervention, rather than using ammonia as a premixed fuel. Therefore, the dilution, free radical competition, and reaction path modulation effects of ammonia at the edge of the hydrogen jet can be studied more precisely.

[0032] Alternatively, the micropore diameter can be increased to 0.6–1.0 mm. Furthermore, annular slits (single annular slits) can be used instead of multiple discrete pores, providing a more uniform circumferential ammonia distribution.

[0033] In some embodiments, the high-pressure hydrogen supply module includes: a high-pressure hydrogen source 1, a pressure reducing valve 2, a second mass flow controller 4, and a high-pressure hydrogen main chamber 5; the high-pressure hydrogen source 1, the pressure reducing valve 2, the flow controller, and the high-pressure hydrogen main chamber 5 are connected in sequence; the outlet of the high-pressure hydrogen main chamber 5 is connected to the inlet end of the venting guide section 9, and a rupture disc 12 is provided between the two.

[0034] This embodiment precisely controls the hydrogen entering the high-pressure hydrogen main chamber 5 through the pressure reducing valve 2 and the second mass flow controller 4, enabling the setting of hydrogen pressure and mass within the main chamber according to experimental requirements. The rupture disc 12 acts as a release trigger element, rupturing when the main chamber pressure reaches the set value, generating a near-instantaneous pulse release. This simulates leakage conditions caused by accidental rupture of the high-pressure hydrogen storage container or valve failure. The introduction of the mass flow controller allows for repeatable hydrogen filling amounts in each experiment, ensuring consistency in initial release conditions and facilitating comparison of spontaneous combustion suppression effects under different ammonia blending ratios. Logically, this module, in conjunction with the anti-liquefaction ammonia supply module, enables independent adjustment of hydrogen release parameters and ammonia injection parameters.

[0035] Alternatively, the pressure reducing valve 2 and the second mass flow controller 4 can be omitted, and the high-pressure hydrogen source 1 can be used to directly fill the main chamber with gas via a manual valve.

[0036] In some embodiments, the pipeline upstream of the solenoid valve 19 is pre-filled with pressurized ammonia; the solenoid valve 19 automatically opens when releasing high-pressure hydrogen, allowing upstream ammonia to be injected into the release guide section 9 through the ammonia mixing port 7; in the non-release state, the solenoid valve 19 remains closed to prevent ammonia from flowing out.

[0037] In this embodiment, pressurized ammonia is pre-filled in the upstream pipeline of the electronically controlled valve 19, and the electronically controlled valve 19 is automatically opened when high-pressure hydrogen is released, so that the ammonia injection and hydrogen release are automatically synchronized, and an ammonia flame-suppressing layer is formed in the boundary layer at the moment of hydrogen release.

[0038] Specifically, an electronically controlled valve 19 can be linked to the rupture signal of the rupture disc 12. In particular, a pressure sensor 6 or a fragment detection switch (such as a patch strain sensor or fiber optic fragment indicator) is installed in the high-pressure hydrogen main chamber 5 or the venting guide section 9 upstream of the rupture disc 12. When the rupture disc 12 ruptures, causing a sudden drop in pressure or generating a shock wave signal, the control module 24 sends an opening command to the electronically controlled check valve within a microsecond delay (e.g., ≤50μs), so that the pre-charged pressurized ammonia gas upstream is injected into the venting guide section 9 through the ammonia mixing port 7 within a very short time (e.g., ≤200μs) after the start of venting.

[0039] In some examples, the electrically controlled valve 19 with check function is an integrated set of electrically controlled shut-off valve and check valve. The two can be integrated in series or one valve can be set inside the other valve to achieve integration.

[0040] In some embodiments, a nitrogen purging module is also included, which is connected to the venting guide section 9 via a pipeline and is used to purge and purge the venting guide section 9.

[0041] This embodiment, by incorporating a nitrogen purging module, allows for the purging of the release guide section 9 and connecting pipelines before and after the experiment, removing residual hydrogen, ammonia, or reaction products. Logically, this prevents residual combustible gases from causing accidental premature ignition or altering the initial atmosphere in subsequent experiments, thereby improving experimental safety and data repeatability. Especially in experiments suppressing spontaneous combustion, residual combustion products or unreacted ammonia from previous experiments in the pipelines can interfere with ignition delay and flame morphology measurements in subsequent experiments. Therefore, nitrogen purging is a necessary step to ensure the reproducibility of experimental conditions.

[0042] Alternatively, argon or carbon dioxide can be used as purging gas. In addition, the nitrogen replacement module can be linked with the reflux valve of the anti-liquefaction ammonia supply module to achieve joint purging of the ammonia pipeline.

[0043] In some embodiments, the anti-liquefaction ammonia supply module further includes a control module 24; the control module 24 is used to collect the temperature of ammonia gas after vaporization and overheating in the anti-liquefaction ammonia supply module, the ammonia gas pressure at the outlet of the buffer pressure stabilizing tank 18, and the ammonia gas dew point temperature measured by the sampling branch, and to perform closed-loop control of the heating power, reflux valve and nitrogen purging valve according to the above-detected signals; when the ammonia supply side is detected to deviate from the full gas phase window, the reflux, pressure reduction, ammonia supply cut-off and nitrogen purging operations are automatically executed.

[0044] This embodiment uses control module 24 to monitor three key parameters—temperature, pressure, and dew point—in real time and calculates superheat (actual temperature minus saturation temperature). Logically, it can accurately determine whether ammonia is within the full gas phase window (e.g., ΔT ≥ 15℃). When insufficient superheat or abnormal dew point is detected, the system automatically increases heating power, opens the reflux valve, or reduces pressure. If the situation cannot be resolved, the ammonia supply is immediately cut off, and nitrogen purging is switched on. This closed-loop control scheme eliminates the risk of liquid ammonia entering downstream pipelines at the source, ensuring the consistency of ammonia phase in each experiment, thus making the control of the blending ratio repeatable. At the same time, the interlock protection significantly improves the safety of the device, preventing liquid ammonia from vaporizing and absorbing heat in the micropores, which could lead to freezing or blockage.

[0045] Alternatively, heating power and pressure can be manually adjusted, relying on operators to monitor dew point instruments for intervention. Control parameters can also be set using only temperature and pressure (for calculating superheat) without a dew point sensor; however, a dew point sensor provides a more reliable, direct verification method, detecting trace amounts of moisture or incompletely removed droplets in ammonia. Furthermore, a reflux valve can be omitted, and anomalies can be handled simply by cutting off the ammonia supply and purging.

[0046] In some embodiments, the sidewall of the discharge guide section 9 is provided with a visualization observation window 8; the recording module includes a high-frequency dynamic pressure sensor and a photoelectric probe installed on the wall of the discharge guide section 9, and a camera system 10 disposed outside the discharge guide section 9; the response frequency of the high-frequency dynamic pressure sensor is not less than 100kHz; the camera system 10 includes at least one of a schlieren imager, a high-speed camera, and a PLIF measurement system.

[0047] This embodiment, by incorporating a visualization observation window 8, a high-frequency dynamic pressure sensor, a photoelectric probe, and a high-speed camera system 10 into the discharge guidance section 9, can simultaneously capture shock wave propagation, pressure wave arrival time, self-luminous signals, and flame morphology evolution during the discharge process. The high-frequency dynamic pressure sensor (≥100kHz) can capture pressure spikes in milliseconds or even microseconds after the rupture disc 12 ruptures; the photoelectric probe can detect ultraviolet / visible radiation at the moment of spontaneous combustion; and schlieren or PLIF can visualize the jet boundary layer structure and ammonia distribution. Logically, multi-parameter synchronous recording can accurately determine the ignition delay time (the time difference from the start of discharge to the appearance of self-luminous emission) and the impact of ammonia on the shock wave structure and mixing layer, thereby quantitatively evaluating the ammonia suppression effect. This is something that cannot be achieved by traditional observation using only a single high-speed camera.

[0048] In some embodiments, the discharge guide section 9 is provided with an optical diagnostic interface.

[0049] This embodiment, by setting up a dedicated optical diagnostic interface (such as a standard threaded interface or flange interface), can easily connect to external optical equipment (such as laser sheet light sources, fiber optic probes, beam splitters, etc.) to achieve more advanced measurement methods, such as PLIF (planar laser-induced fluorescence) quantitative measurement of ammonia concentration distribution, PIV (particle image velocimetry) measurement of flow field velocity, or absorption spectroscopy measurement of temperature. Logically, this interface gives the experimental device good scalability, allowing the optical diagnostic module to be replaced or added according to different research needs without requiring secondary processing of the discharge guide section 9. At the same time, the standard interface ensures equipment interchangeability and comparability of experimental data between different laboratories.

[0050] Example 2 This invention also provides a method for suppressing spontaneous combustion of high-pressure hydrogen gas during leakage using the experimental apparatus described in the above embodiments, comprising the following steps: S1: Activate the anti-liquefaction ammonia supply module to heat the ammonia to a full gas phase state, and detect the temperature, pressure and dew point of the ammonia to ensure that the ammonia meets the preset superheat requirements; S2: Ammonia gas in its entire gas phase state is set to the target flow rate through a mass flow controller and pre-charged into the upstream pipeline of ammonia mixing port 7; S3: Fill the high-pressure hydrogen supply module with high-pressure hydrogen to the preset pressure; S4: Trigger the rupture disc 12 (specifically, the rupture disc 12 may break when the hydrogen pressure in the high-pressure hydrogen main chamber 5 reaches the preset pressure, or it may be broken by some other physical triggering means), so that the high-pressure hydrogen is released into the release guide section 9, and at the same time, ammonia is injected from the ammonia mixing port 7 into the boundary layer of the high-pressure hydrogen jet. The two are mixed and then enter the test environment. S5: The recording module synchronously records the venting plume, pressure wave, and ignition delay time to evaluate the inhibitory effect of ammonia on spontaneous combustion of high-pressure hydrogen leaks.

[0051] This embodiment provides a complete experimental procedure, the core of which lies in "first establishing a full-phase ammonia gas and pre-charging it into the pipeline, then filling it with hydrogen, and finally triggering the venting and recording simultaneously." Unlike existing pre-mixing methods (mixing before venting), in this method, ammonia and hydrogen do not come into contact before venting, avoiding the risk of ammonia liquefaction in a high-pressure hydrogen environment. The superheat detection in step S1 ensures that the ammonia is always a single-phase gas, and the pre-charging in step S2 allows the ammonia to be ejected from the micro-orifice with a millisecond-level response speed, synchronized with the hydrogen venting. The multi-parameter synchronous recording in step S5 can quantitatively provide key indicators such as ignition delay time, pressure wave peak value, and flame propagation speed. By changing the target flow rate (i.e., the ammonia doping ratio) in step S2, the suppression law of spontaneous combustion by different ammonia doping amounts can be systematically studied, thus providing experimental basis for engineering safety design. This method has good repeatability and high safety, filling the gap in experimental methods for suppressing spontaneous combustion of high-pressure hydrogen by boundary ammonia doping.

[0052] In some embodiments, based on the experimental method described in the above embodiments, this embodiment further includes a nitrogen purging step S0 before starting the anti-liquefaction ammonia supply module: opening the nitrogen replacement module to replace the gas supply pipeline with nitrogen.

[0053] Specifically, S0 includes: closing the ammonia shut-off valve of the anti-liquefaction ammonia supply module and the hydrogen valve of the high-pressure hydrogen supply module, opening the purge valve of the nitrogen replacement module, allowing nitrogen to flow sequentially through the high-pressure hydrogen main chamber 5, the venting guide section 9, and the ammonia pipeline upstream of the one-way valve in the anti-liquefaction ammonia supply module, with a purge time of not less than 30 seconds to completely replace the air, water vapor, or flammable gas remaining from the previous experiment in the pipeline; after the purge is completed, closing the purge valve of the nitrogen replacement module and performing a pressure check on the system, and proceeding to the next step only after confirming that there is no leakage.

[0054] This embodiment effectively removes oxygen, water vapor, and residual combustible gases (such as hydrogen or ammonia not completely purged from the previous experiment) from the gas supply pipeline and test chamber by introducing a nitrogen purging step before the experiment begins. Logically, the presence of oxygen and water vapor may interfere with the measurement of the critical conditions for spontaneous combustion of high-pressure hydrogen leakage (e.g., water vapor is endothermic or participates in free radical reactions), while residual hydrogen or ammonia may change the initial mixing ratio of this experiment or lead to accidental ignition. Nitrogen purging ensures that the initial experimental atmosphere is a pure nitrogen environment (or close to air but without any combustible residue), so that the spontaneous combustion process of the hydrogen jet mixing with air after the rupture disc 12 is broken is only affected by the ammonia injected this time, improving the repeatability and reliability of experimental data. In addition, the pressure holding check after purging can detect potential pipeline leaks in advance, ensuring the safety of the high-pressure experiment.

[0055] In some embodiments, before step S2, the method further includes: establishing a target blending ratio. Specifically, the control module 24 calculates the required ammonia mass flow rate based on the experimentally set ammonia blending ratio (e.g., 5% by volume or mass) and the mass flow rate during high-pressure hydrogen release. The mass flow rate during high-pressure hydrogen release is indirectly calculated using the critical flow formula after measuring the initial pressure and initial temperature in the high-pressure hydrogen main chamber before the rupture disc breaks, and after introducing a compressibility factor Z to correct for the actual gas effect. Alternatively, the mass flow rate during hydrogen release can be obtained through other means, such as installing a high-frequency dynamic pressure sensor and a Venturi nozzle upstream of the release guide section, and directly calculating the transient flow rate by combining real-time differential pressure measurement; or using a pre-calibrated method to establish an empirical mapping curve between hydrogen mass flow rate and initial parameters through multiple release experiments for different rupture disc specifications and initial pressure conditions, for subsequent experimental reference. The control module 24 sends the calculated ammonia mass flow rate as a set value to the mass flow controller in the anti-liquefaction ammonia supply module, so that the ammonia pipeline is stabilized at the target flow rate before the release, thereby realizing the pre-establishment of the blending ratio.

[0056] In some embodiments, at any time during steps S1 to S5, if the control module 24 detects any of the following abnormalities: ΔT < 0°C, dew point temperature close to T actual If the pressure in buffer pressure tank 18 is >0.8MPa, the pressure in venting guide section 9 fluctuates abnormally, or an unexpected flame is detected by the photoelectric probe, the following actions should be taken immediately: close the ammonia shut-off valve, open the nitrogen purge valve, close the hydrogen valve, trigger the alarm, and record the abnormal data.

[0057] In some embodiments, step S2: Ammonia supply preparation to prevent liquefaction. The ammonia shut-off valve is opened, and the vaporization superheater 15 is started to heat to the set temperature (e.g., 80°C). The control module 24 reads the temperature T after the outlet of the membrane separator 16. actual and pressure P NH3Calculate the saturation temperature T sat(PNH3) (Using the Antoine equation or by looking up a table), the superheat ΔT = T is obtained. actual -T sat(PNH3) Simultaneously, the dew point sensor value is read. If ΔT ≥ 15℃ and the dew point is normal, proceed to the next step; if 5℃ ≤ ΔT < 15℃, the control module 24 increases the heating power of the vaporization superheater 15; if ΔT < 5℃ or the dew point is abnormal, the control module 24 opens the return channel valve and slightly reduces the set pressure of the mass flow controller (through the pressure regulating valve 21). If it does not recover after 5 seconds, the ammonia shut-off valve is closed and the nitrogen purge valve is opened, triggering an alarm.

[0058] In some embodiments, step S2 employs double confirmation: first, a small amount of ammonia gas (the mass flow controller is set to 5% of full scale) is introduced into the venting guide section 9, and after stabilization, ΔT and dew point are detected. Only after confirming that there is no droplet signal is the formal test allowed to proceed.

[0059] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An experimental device for suppressing spontaneous combustion of high-pressure hydrogen gas through ammonia mixing, characterized in that, include: The high-pressure hydrogen supply module is used to provide high-pressure hydrogen as a venting gas source; The anti-liquefaction ammonia supply module is used to maintain ammonia in a fully gaseous state before sending it into the staged blending module. The staged blending module includes a venting guide section and an ammonia blending port located circumferentially at the inlet end of the venting guide section; the inlet end of the venting guide section is connected to the high-pressure hydrogen supply module, and its outlet end is connected to the atmosphere; the anti-liquefaction ammonia supply module is connected to the ammonia blending port and is used to inject ammonia into the boundary of the high-pressure hydrogen jet when venting high-pressure hydrogen. The recording module is used to record the venting plume, pressure wave, and ignition delay time.

2. The experimental apparatus according to claim 1, characterized in that, The anti-liquefaction ammonia supply module includes: an ammonia source, a vaporization superheater, a membrane precipitator, a buffer pressure stabilizing tank, a dew point monitoring chamber, a first mass flow controller, and an electrically controlled valve with a check valve function. The ammonia source, vaporization superheater, membrane separator, buffer pressure stabilizing tank, first mass flow controller, and electric control valve are connected in sequence, and the outlet of the electric control valve is connected to the ammonia mixing port. The liquid outlet of the membrane separator is connected to the ammonia source or a separately installed reflux collection tank via a reflux valve. The dew point monitoring chamber is connected to the outlet of the buffer pressure stabilizing tank via a sampling branch, and is used to continuously extract gas for dew point measurement.

3. The experimental apparatus according to claim 2, characterized in that, The ammonia mixing port is composed of multiple injection micro-holes with a diameter of 0.2 mm to 0.5 mm. The injection direction of the injection micro-holes is inclined downstream along the axial direction of the discharge guide section, or radially inward towards the central axis of the discharge guide section.

4. The experimental apparatus according to claim 1, characterized in that, The high-pressure hydrogen supply module includes: a high-pressure hydrogen source, a pressure reducing valve, a second mass flow controller, and a high-pressure hydrogen main chamber; the high-pressure hydrogen source, pressure reducing valve, flow controller, and high-pressure hydrogen main chamber are connected in sequence; the outlet of the high-pressure hydrogen main chamber is connected to the inlet end of the venting guide section, and a rupture disc is provided between the two.

5. The experimental apparatus according to claim 2, characterized in that, The pipeline upstream of the electrically controlled valve is pre-filled with pressurized ammonia gas; the electrically controlled valve automatically opens when releasing high-pressure hydrogen gas, allowing upstream ammonia gas to be injected into the release guide section through the ammonia mixing port; in the non-release state, the electrically controlled valve remains closed to prevent ammonia gas from flowing out.

6. The experimental apparatus according to claim 2, characterized in that, It also includes a nitrogen purging module, which is connected to the venting guide section via a pipeline and is used to purge and purge the venting guide section.

7. The experimental apparatus according to claim 6, characterized in that, The anti-liquefaction ammonia supply module also includes a control module; the control module is used to collect the temperature of ammonia gas after vaporization and overheating in the anti-liquefaction ammonia supply module, the ammonia gas pressure at the outlet of the buffer pressure stabilizing tank, and the ammonia gas dew point temperature measured by the sampling branch, and to perform closed-loop control of the heating power, reflux valve and nitrogen purging valve based on the above-detected signals; when the ammonia supply side is detected to deviate from the full gas phase window, the module automatically performs reflux, pressure reduction, ammonia supply cut-off and nitrogen purging operations.

8. The experimental apparatus according to claim 1, characterized in that, The side wall of the discharge guide section is provided with a visual observation window; the recording module includes a high-frequency dynamic pressure sensor and a photoelectric probe installed on the wall of the discharge guide section, as well as a camera system set outside the discharge guide section; The response frequency of the high-frequency dynamic pressure sensor is not less than 100kHz; the camera system includes at least one of a schlieren imager, a high-speed camera, and a PLIF measurement system.

9. The experimental apparatus according to claim 8, characterized in that, The discharge guide section is equipped with an optical diagnostic interface.

10. A method for suppressing spontaneous combustion of high-pressure hydrogen leakage using the experimental apparatus described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Activate the anti-liquefaction ammonia supply module to heat the ammonia to a full gas phase state, and detect the temperature, pressure and dew point of the ammonia to ensure that the ammonia meets the preset superheat requirements; S2: Ammonia gas in its entire gas phase is set to the target flow rate through a mass flow controller and pre-charged into the upstream pipeline of the ammonia mixing port; S3: Fill the high-pressure hydrogen supply module with high-pressure hydrogen to the preset pressure; S4: Trigger the rupture disc to release high-pressure hydrogen into the release guide section, while ammonia is injected from the ammonia mixing port into the boundary layer of the high-pressure hydrogen jet. The two mix and then enter the test environment. S5: The recording module synchronously records the venting plume, pressure wave, and ignition delay time to evaluate the inhibitory effect of ammonia on spontaneous combustion of high-pressure hydrogen leaks.

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