A small-scale visual hydrogen explosion monitoring system and a monitoring method

Abstract

The application discloses a small-scale visual hydrogen explosion monitoring system and a monitoring method, and belongs to the field of hydrogen explosion monitoring.The application comprises an explosion pipeline system, a gas distribution system, an ignition system, a test and data acquisition system.Through forming sodium chloride crystals in the pipeline, based on the flame color reaction of sodium, the invisible hydrogen flame in the ultraviolet wave stage is colored, further, the sodium lamp is used to deepen the flame color, the capture ability of a high-speed camera on the flame form and position is improved, the hydrogen flame propagation speed can be calculated more accurately, the relationship between the hydrogen flame form and the flame propagation speed is analyzed, and the propagation law of pressure and flame is quantitatively characterized; based on a semiconductor laser, the ignition and initiation at different positions in the pipeline can be realized by using the high-thermal-conductivity characteristics of copper, and the dynamic change characteristics of the bidirectional flame propagation with time are analyzed.The application can predict the space-time evolution law of hydrogen combustion and explosion in a confined space, and provide support for safety design, accident prevention and control and the like of hydrogen-related industries.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen explosion monitoring, specifically relating to a small-scale visualized hydrogen explosion monitoring system and method. Background Technology

[0002] Because hydrogen explosions occur in the ultraviolet band, they are invisible to the naked eye and conventional high-speed cameras, making them impossible to capture and hindering quantitative research on their propagation speed and morphology. Compared to other common flammable and explosive gases such as methane and propane, hydrogen has a wider explosion limit range, lower ignition energy, and faster flame propagation speed, making it highly susceptible to combustion and explosion accidents at all stages of production, storage, transportation, refueling, and use. Due to its small molecular weight, hydrogen combustion is highly susceptible to gravitational influences, resulting in strong instability and wrinkling of the flame surface, thus accelerating flame propagation. Especially in confined spaces, it can easily develop into supersonic propagation, leading to deflagration and detonation, causing even greater casualties. However, as a clean and renewable energy source, hydrogen energy has become an important direction for global energy development, and its safety has become a major bottleneck restricting the development of the hydrogen energy industry.

[0003] To address the issue of hydrogen flame propagation, current methods primarily rely on schlieren technology to monitor flame morphology. However, due to limitations in schlieren area, the monitoring range is less than 1 meter, and schlieren equipment is affected by focal length and optical path, placing significant demands on the test space. For hydrogen explosion propagation speed, pressure sensors are often used to measure the explosion wave velocity, while ultraviolet light sensors are used to calculate the hydrogen flame propagation speed. In addition, many experiments enhance the visualization of hydrogen flames by adding gases such as methane and ethylene, which are visible after combustion, but this alters the characteristic parameters of hydrogen combustion and explosion to some extent, increasing experimental errors. Therefore, conducting research on the mechanism and laws of hydrogen combustion and explosion, and establishing a hydrogen combustion and explosion monitoring experimental system, not only has significant academic value but also provides data support for the safe development of the hydrogen production, storage, and transportation industries, thus possessing important application value. Summary of the Invention

[0004] The main objective of this invention is to provide a small-scale visualized hydrogen explosion monitoring system and method, which can reduce the difficulty of measuring the flame velocity of hydrogen explosions, improve the accuracy of flame identification, and quantitatively monitor the relationship between the morphology and propagation speed of hydrogen flames.

[0005] The objective of this invention is achieved through the following technical solution.

[0006] The present invention discloses a small-scale visual hydrogen explosion monitoring system, including a pressure sensor, a sleeve, a glass tube, a laser carrier, a vacuum gauge, a semiconductor laser, a laser head, a sodium lamp, a high-speed camera, and a mixed gas cylinder.

[0007] A glass tube is placed in a sleeve with an observation window; a pressure sensor is connected to the sleeve to collect the pressure in the glass tube; a mixing cylinder is used to supply the glass tube with a hydrogen-air / oxygen mixture; the initial explosion pressure is recorded by a vacuum gauge; the laser carrier is placed in the glass tube and can slide freely on the side wall of the glass tube; a sodium lamp is used to irradiate the glass tube to deepen the flame color reaction of hydrogen combustion in the experiment; a high-speed camera is used to capture images of the shape and position of the hydrogen flame; the laser emitted by the semiconductor laser is irradiated onto the laser carrier by the laser head to achieve ignition.

[0008] Preferably, the sleeve is made entirely of Q235 steel.

[0009] Preferably, the glass tube is made of high borosilicate glass with a boron content of 12.5-13.5% and a silicon content of 78-80%.

[0010] As a preferred option, when performing a vacuum operation on the pipeline, the pipeline's airtightness is considered to have met the experimental requirements when the vacuum gauge reading is 0-1 kPa and remains stable.

[0011] Preferably, the laser carrier is composed of a combination of copper and iron sheets. The copper sheet has a high thermal conductivity and is used to receive laser radiation, while the iron sheet facilitates the movement of the laser carrier.

[0012] Preferably, the semiconductor laser has a wavelength of 915±10nm, the optical power radiated from the output head is greater than 80W, the laser fiber core diameter is 105μm, and the laser start time is adjusted by external control.

[0013] As a preferred option, the sodium lamp is a low-pressure sodium lamp with a power greater than 20W. During the experiment, it is placed in front of the explosion pipeline system so that the entire pipeline is under the sodium lamp light source. A high-speed camera is used to capture the explosion process and analyze the explosion flame velocity.

[0014] The present invention discloses a working method for a small-scale visualized hydrogen explosion monitoring system, comprising the following steps:

[0015] Step 1: Move the laser carrier to the set ignition position on the glass tube wall using a magnet and fix it in place;

[0016] Step 2: Sodium chloride crystals form on the inner wall of the glass tube;

[0017] Step 3: Place the glass tube into the sleeve and secure it with the bolts on the flange;

[0018] Step 4: Connect the pressure sensor to one end of the pipe through the internal thread (19) on the sleeve;

[0019] Step 5: Connect the valve to the other end of the pipeline, and connect the vacuum gauge and the mixing cylinder through the four-way valve for quantitative input of gas before the experiment;

[0020] Step 6: Place the semiconductor laser close to the ignition position, ensuring the laser head is perpendicular to the laser carrier;

[0021] Step 7: Place the sodium lamp in front of the glass tube so that its light can illuminate the entire explosion path;

[0022] Step 8: Place the high-speed camera in the designated location to ensure that the field of view can capture the entire process of the explosion flame propagation;

[0023] Step 9: Set up the pressure sensor and data acquisition system, then wait for triggering.

[0024] Step 10: After the experiment, record the images captured by the high-speed camera and the pressure sensor data. Then, open the valve at the end of the pipeline and remove the residual gas in the pipeline using a vacuum pump. Based on the images captured by the high-speed camera and the pressure sensor data, quantitatively analyze the relationship between the hydrogen flame morphology and the propagation speed.

[0025] Sodium chloride crystals are formed on the inner wall of a glass tube. Images of the hydrogen flame's shape and position are captured using a high-speed camera. The method is as follows:

[0026] Step 2.1: Dissolve 36.5g of sodium chloride in 100mL of water at room temperature to form a saturated sodium chloride solution;

[0027] Step 2.2: Spray the saturated sodium chloride solution from Step 2.1 evenly into the glass tube using a pressurized sprayer;

[0028] Step 2.3: Let stand at room temperature until the moisture evaporates and sodium chloride crystals form in the pipe;

[0029] Step 2.4: After ignition, sodium produces a yellow flame under the high temperature of the colorless hydrogen flame.

[0030] Step 2.5: Capture images of the hydrogen flame shape and position using a high-speed camera.

[0031] Beneficial effects:

[0032] 1. The present invention discloses a small-scale visualized hydrogen explosion monitoring system and method, which uses a steel sleeve combined with a high borosilicate glass pipe to achieve full-size visualization, improve the pressure-bearing capacity of the pipe, and solve the problem of difficult threading and drilling of glass containers.

[0033] 2. The present invention discloses a small-scale visualized hydrogen explosion monitoring system and monitoring method. The sodium flame color reaction is a physical reaction, which can avoid explosion test errors caused by the addition of other combustible gases.

[0034] 3. The present invention discloses a small-scale visualized hydrogen explosion monitoring system and method, which is based on a semiconductor laser and utilizes the high thermal conductivity of copper to achieve ignition and detonation at different locations in the pipeline. It analyzes the dynamic changes of the bidirectional flame propagation over time and can predict the spatiotemporal evolution of hydrogen combustion and explosion in confined spaces. By adjusting the semiconductor laser and the laser carrier, the detonation position can be changed to simulate pipeline explosion accidents at different locations in actual working conditions.

[0035] 4. The present invention discloses a small-scale visualized hydrogen explosion monitoring system and method, which, based on the flame color reaction of sodium, makes the invisible hydrogen flame in the ultraviolet stage visible. Furthermore, sodium lamps are used to deepen the flame color, improve the ability of high-speed cameras to capture the flame shape and position, and can more accurately calculate the hydrogen flame propagation speed, analyze the relationship between the hydrogen flame shape and the flame propagation speed, and quantitatively characterize the propagation law of pressure and flame. In other words, the use of sodium lamps can greatly improve the capture of hydrogen flame shape and enhance the quantitative analysis of hydrogen flame and speed.

[0036] 5. The present invention discloses a small-scale visual hydrogen explosion monitoring system and method, wherein 36.5g of sodium chloride is dissolved in 100mL of water at room temperature to form a saturated sodium chloride solution; the saturated sodium chloride solution is evenly sprayed into a glass tube through a pressurized sprayer; after standing at room temperature, sodium chloride crystals are formed in the tube after the water evaporates, which can improve the accuracy of hydrogen explosion monitoring. Attached Figure Description

[0037] Figure 1 This is a diagram of a hydrogen explosion monitoring system according to an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of the high borosilicate glass tube structure according to an embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram of the steel sleeve used in implementing the present invention.

[0040] In the diagram: 1—Pressure sensor; 2—Sleeve; 3—Glass tube; 4—Laser carrier; 5—Bolt; 6—Valve; 7—Vacuum gauge; 8—Four-way valve; 9—First silicone gasket; 10—Flange; 11—Second silicone gasket; 12—Semiconductor laser; 13—Laser head; 14—Sodium lamp; 15—Computer; 16—High-speed camera; 17—Mixed gas cylinder; 18—Vacuum pump; 19—First internal thread; 20—Second internal thread. Detailed Implementation

[0041] This invention is mainly used to test and analyze the propagation law of hydrogen combustion flame and pressure in confined spaces with multiple ignition points, so as to quantitatively characterize the relationship between folding and acceleration in the hydrogen flame morphology, and provide data support for the design of safe distances, accident prevention and control and the formulation of emergency plans for the "hydrogen-related industry".

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] This embodiment of a small-scale visualized hydrogen explosion monitoring method includes the following steps:

[0044] Step 1: Dissolve 36.5g of sodium chloride in 100mL of water at room temperature to form a saturated sodium chloride solution;

[0045] Step 2: Evenly spray the saturated sodium chloride solution from Step 1 into the glass tube using a pressurized sprayer;

[0046] Step 3: Let stand at room temperature until the moisture evaporates and sodium chloride crystals form in the pipe;

[0047] Step 4: After ignition, sodium produces a yellow flame under the high temperature of the colorless hydrogen flame.

[0048] Step 5: Capture images of the hydrogen flame shape and position using a high-speed camera.

[0049] This embodiment discloses a small-scale visualized hydrogen explosion monitoring system, used to implement the small-scale visualized hydrogen explosion monitoring method of this embodiment. The small-scale visualized hydrogen explosion monitoring system includes a pressure sensor 1, a sleeve 2, a glass tube 3, a laser carrier 4, a bolt 5, a valve 6, a vacuum gauge 7, a four-way valve 8, a first silicone gasket 9, a flange 10, a second silicone gasket 11, a semiconductor laser 12, a laser head 13, a sodium lamp 14, a computer 15, a high-speed camera 16, a mixed gas cylinder 17, a vacuum pump 18, a first internal thread 19, a second internal thread 20, and a data acquisition system 21.

[0050] Sleeve 2 is 3mm thick, 1532mm long, and has an inner diameter of 40mm. The sleeve consists of two symmetrical parts, cut at both ends to provide an explosion observation window, 1500mm long and 20mm high. A flange 10 is welded in the middle and fixed with bolts 5. The sleeve has a first internal thread 19 and a second internal thread 20 welded to both ends. The nominal diameter is DN20, and the sleeve is 16mm long. Figure 3 As shown.

[0051] Glass tube 3 is made of high borosilicate glass, with a length of 1500mm, an inner diameter of 20mm, and a thickness of 10mm. Figure 2 As shown.

[0052] The laser carrier 4 is composed of stacked copper and iron sheets, each 0.5mm thick, 10mm long, and 10mm wide, bonded together with JL-6218 metal adhesive. The laser head 13 is placed perpendicular to the copper sheet surface of the carrier. The first silicone pad 9 and the second silicone pad 11 are both 2mm thick. The pressure sensor 1 at the left end of the sleeve is connected to the steel sleeve via a fixture; the fixture's dimensions match the internal thread size, being DN20. The valve 6 at the right end of the sleeve is connected to the vacuum pump 18, the vacuum gauge 7, and the mixed gas cylinder 17 via a four-way valve 8. At this point, the inside of the pipeline is completely sealed. Figure 1 As shown;

[0053] Other devices include: a sodium lamp 14 for flame testing; a semiconductor laser 12; a data acquisition system 21; and a high-speed camera 16 connected to a computer 15 for data monitoring.

[0054] The implementation process of a small-scale visualized hydrogen explosion monitoring system disclosed in this embodiment is as follows:

[0055] If the ignition point is not at one end of the pipeline, two hydrogen explosions will occur. Since the initial conditions and ignition energy of the gas in the pipeline are the same, the two explosions are only affected by the propagation distance. The accumulated overpressure will interact with each other, producing different degrees of disturbance, resulting in differences in the overall explosion intensity.

[0056] First, select the detonation location, place the laser carrier 4 at the designated ignition position using a magnet, and fix it in place;

[0057] Prepare a saturated sodium chloride solution and evenly disperse the solution on the inner wall of glass tube 3 using a pressurized sprayer;

[0058] After the liquid evaporates and sodium chloride crystals cover the tube wall, place silicone gaskets 9 and 11 on both sides of the glass tube to prevent the glass tube from breaking due to the explosive impact vibration.

[0059] Place the glass tube 3 into the sleeve 2 and connect it through the flange 10 using bolts 5;

[0060] To ensure the airtightness of the pipeline, six bolts are installed on the flange, but this is not the only option; more bolts can be added depending on the structural stability.

[0061] Install pressure sensor 1, valve 6 and other components into internal thread 19 to form a sealed space in the pipeline;

[0062] Pressure sensor 1 is a piezoelectric wall sensor used to measure the overpressure during an explosion in the experiment;

[0063] The vacuum gauge 7, the mixed gas cylinder 17, and the vacuum pump 18 are connected via a four-way connector 8 for gas delivery.

[0064] Turn on vacuum pump 18 to evacuate the pipeline, observe the reading of vacuum gauge 7, and stop vacuum pump 18 when the pressure in the pipeline stabilizes at 0-1 kPa.

[0065] Open the mixed gas cylinder 17 and fill it with a hydrogen-air / oxygen mixture at a certain initial pressure through the vacuum gauge 7.

[0066] The movable semiconductor laser 12 is placed near the laser carrier 4, so that the laser head 13 is perpendicular to the copper sheet on the laser carrier to obtain higher thermal conductivity.

[0067] Turn on the low-pressure sodium lamp 14 to expose the entire pipeline to the sodium lamp light source, and simultaneously turn on the high-speed camera 16;

[0068] Connect the high-speed camera 16 to the computer 15 so that the camera can capture the entire pipe and produce a clear image.

[0069] The pressure sensor 1 is connected to the data acquisition system 21 and controlled by a computer.

[0070] Ignition and detonation are performed, and images captured by high-speed camera 16 and data from pressure sensor 1 are recorded. The flame propagation speed can be obtained by measuring the size of the captured image and the pixel size. At the same time, the relationship between the flame propagation speed and the explosion pressure can be obtained based on the pressure data.

[0071] After the test, open valve 6 at the end of the pipeline and remove the residual gas in the pipeline using vacuum pump 18.

[0072] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A small-scale visual hydrogen explosion monitoring system, characterized in that, Includes pressure sensor (1), sleeve (2), glass tube (3), laser carrier (4), vacuum gauge (7), semiconductor laser (12), laser head (13), sodium lamp (14), high-speed camera (16), and gas mixing cylinder (17). The glass tube (3) is placed in the sleeve (2) with an observation window; the pressure sensor (1) is connected to the sleeve (2) to collect the pressure in the glass tube (3); the mixed gas cylinder (17) is used to provide the glass tube (3) with a hydrogen-air / oxygen mixture; the initial explosion pressure is recorded by the vacuum gauge (7); the laser carrier (4) is placed in the glass tube (3) and can slide freely on the side wall of the glass tube (3); the saturated sodium chloride solution is sprayed evenly into the glass tube by a pressurized sprayer; after standing at room temperature, sodium chloride crystals are formed in the tube after the water evaporates, thus realizing the flame color reaction during the explosion process; the sodium lamp (14) is used to irradiate the glass tube (3) to deepen the flame color reaction of hydrogen combustion in the experiment; the high-speed camera (16) is used to collect images of the shape and position of the hydrogen flame; the laser emitted by the semiconductor laser (12) is irradiated onto the laser carrier (4) through the laser head (13) to realize ignition.

2. The small-scale visual hydrogen explosion monitoring system as described in claim 1, characterized in that: The sleeve (2) is made of Q235 steel.

3. The small-scale visual hydrogen explosion monitoring system as described in claim 1, characterized in that: The glass tube is made of high borosilicate glass with a boron content of 10-15% and a silicon content of 78-80%.

4. The small-scale visual hydrogen explosion monitoring system as described in claim 1, characterized in that: When a vacuum is applied to the pipeline, the pipeline is considered to have met the experimental requirements when the reading of the vacuum gauge (7) is 0~1KPa and remains stable.

5. The small-scale visualized hydrogen explosion monitoring system as described in claim 1, characterized in that: The laser carrier is composed of copper and iron sheets. The copper sheets have a high thermal conductivity and are used to receive laser radiation, while the iron sheets facilitate the movement of the laser carrier.

6. The small-scale visual hydrogen explosion monitoring system as described in claim 1, characterized in that: The semiconductor laser (12) has a wavelength of 915±10nm, and the optical power emitted by the output head is greater than 80W. The laser fiber core diameter is 105μm, and the laser start time can be adjusted by external control.

7. The small-scale visual hydrogen explosion monitoring system as described in claim 1, characterized in that: The sodium lamp is a low-pressure sodium lamp with a power greater than 20W. During the experiment, it is placed in front of the explosion pipeline system so that the entire pipeline is under the sodium lamp light source. A high-speed camera is used to film the explosion process and analyze the explosion flame velocity.

8. A method for monitoring hydrogen explosions using a small-scale visual hydrogen explosion monitoring system as described in any one of claims 1 to 7, characterized in that: Includes the following steps, Step 1: Move the laser carrier (4) to the set ignition position on the wall of the glass tube (3) using a magnet and fix it in place; Step 2: Sodium chloride crystals are formed on the inner wall of the glass tube (3); Step 3: Place the glass tube (3) into the sleeve (2) and fix it with bolts (5) on the flange (10); Step 4: Connect the pressure sensor (1) to one end of the pipe through the internal thread (19) on the sleeve (2); Step 5: Connect valve (6) to the other end of the pipeline, and connect vacuum gauge (7) and gas mixing cylinder (17) through four-way valve (8) for quantitative input of gas before experiment; Step 6: Place the semiconductor laser (12) close to the ignition position, and position the laser head (13) perpendicular to the laser carrier (4); Step 7: Place the sodium lamp (14) in front of the glass tube (3) so that its light can illuminate the entire explosion channel; Step 8: Place the high-speed camera (16) in the designated position to ensure that the field of view can capture the entire process of the explosion flame propagation; Step 9: Set up the pressure sensor and data acquisition system, then wait for triggering; Step 10: After the experiment, record the images captured by the high-speed camera and the pressure sensor data. Then, open the valve at the end of the pipeline and remove the residual gas in the pipeline using a vacuum pump. Based on the images captured by the high-speed camera and the pressure sensor data, quantitatively analyze the relationship between the hydrogen flame morphology and the propagation speed.

9. The method for monitoring hydrogen explosion as described in claim 8, characterized in that: Sodium chloride crystals are formed on the inner wall of the glass tube (3). The method to achieve this is as follows: Step 2.1: Dissolve 36.5g of sodium chloride in 100mL of water at room temperature to form a saturated sodium chloride solution; Step 2.2: Spray the saturated sodium chloride solution from Step 2.1 evenly into the glass tube using a pressurized sprayer; Step 2.3: Let stand at room temperature until the moisture evaporates and sodium chloride crystals form in the pipe.

10. A small-scale visualization method for monitoring hydrogen explosions, comprising the following steps: Step 1: Dissolve 36.5g of sodium chloride in 100mL of water at room temperature to form a saturated sodium chloride solution; Step 2: Evenly spray the saturated sodium chloride solution from Step 1 into the glass tube using a pressurized sprayer; Step 3: Let stand at room temperature until the moisture evaporates and sodium chloride crystals form in the pipe; Step 4: After ignition, sodium produces a yellow flame under the high temperature of the colorless hydrogen flame. Step 5: Capture images of the hydrogen flame shape and position using a high-speed camera.

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