Gas diffusion fire inversion test device based on combustion traces

Abstract

The invention discloses a combustion trace-based gas diffusion fire inversion test device, which relates to the technical field of gas diffusion fire accident inversion, and comprises a positioning unit, an ignition unit, a gas injection unit, a recording unit and an analysis unit. The positioning unit comprises a positioning assembly, and the positioning assembly comprises two positioning pieces and a plurality of clamping pieces. The two positioning pieces are clamped and fixed by the clamping piece, so that the combustion sample can be clamped between the two positioning pieces. The positioning piece is a grid so as to provide meshes serving as a gas flowing channel. The ignition unit is used for remotely igniting the combustion sample. The gas injection unit is used for providing combustible gas or combustion-supporting gas for the combustion space. The recording unit is used for recording the gas diffusion process, the remote fire breakout process and the reverse combustion process. The analysis unit is electrically connected with the recording unit and used for receiving and analyzing the combustion process data. Compared with the prior art, the fire disaster inversion test device can provide a basis for inversion of a gas diffusion fire disaster accident through a simulation test mode.

Description

Technical Field

[0001] The present invention relates to the technical field of fire accident inversion, and in particular to a gas diffusion fire inversion test device based on combustion traces. Background Art

[0002] Combustion is an exothermic reaction between combustibles and oxidants. The occurrence of combustion requires three conditions: combustibles, combustion-supporting materials, and an ignition source. Fire investigation work revolves around how combustion occurs at the fire scene and is used to find the location of the fire. In some fire scenes, the location of the fire and the location with the heaviest burn marks are often not in the same location. Therefore, how to trace the source of the fire through the burn marks, analyze the diffusion process of the flammable gas that causes its combustion, the process of long-distance ignition and the spread of the flame from the ignition source to the edge, the process of the flame returning from the edge to the leak port, and the process of the flame continuing to burn at the leak port are technical problems that need to be solved urgently by those skilled in the art. Summary of the Invention

[0003] The purpose of the present invention is to provide a gas diffusion fire inversion test device based on combustion traces, so as to provide a basis for fire inversion through simulation testing.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention discloses a gas diffusion fire inversion test device based on combustion traces, which is characterized by comprising:

[0006] The positioning unit includes a positioning assembly, wherein the positioning assembly includes two positioning members and a plurality of clamping members; the clamping members clamp and fix the two positioning members so that the two positioning members can clamp the combustion sample in the middle; the positioning member is a grid to provide a mesh as a gas flow channel;

[0007] an ignition unit, for igniting the combustion sample;

[0008] A gas injection unit, used to provide combustible gas or combustion-supporting gas to the combustion space;

[0009] Recording unit, used to record gas diffusion, remote fire, and reverse combustion processes;

[0010] an analysis unit, electrically connected to the recording unit, for receiving and analyzing combustion process data;

[0011] The recording unit includes a high-speed camera, a speed and temperature synchronous measurement sensor and a gas concentration sensor to simultaneously collect images, gas flow velocity, gas temperature and gas concentration data; the number of the temperature sensors and the gas concentration sensors is multiple and evenly arranged.

[0012] Preferably, the positioning unit further comprises a column and a position adjustment assembly; the position adjustment assembly is mounted on the column and connected to the positioning member to adjust at least one of the height position and the horizontal position of the positioning member.

[0013] Preferably, the meshes of the upper and lower grilles are positioned opposite each other; the number of the combustion samples is multiple and they are arranged at intervals, and each combustion sample is arranged between the nodes of the two grilles.

[0014] Preferably, the ignition unit comprises a plurality of ignition heads, which are evenly distributed and individually controlled to adjust the ignition position.

[0015] Preferably, the gas injection unit includes a gas cylinder, a pressure reducing valve, a gas injection pipeline, a mass flow meter and a flame arrester; the pressure reducing valve is installed at the bottle mouth of the gas cylinder; the first end of the gas injection pipeline is connected to the pressure reducing valve, and the second end extends to the combustion space; the mass flow meter and the flame arrester are installed on the gas injection pipeline.

[0016] Preferably, the second end of the gas injection pipeline is located at the lower side of the two positioning members and is vertically downward or obliquely downward.

[0017] Preferably, the gas ejected from the second end of the gas injection pipeline contains colored smoke for tracing or ultra-fine non-combustible colored particles with a particle size of less than 30 μm.

[0018] Preferably, the gas diffusion fire inversion test device based on combustion traces further includes a blowing device for adjusting the direction of airflow in the combustion space.

[0019] Preferably, the combustible gas provided by the gas injection unit is methane or propane.

[0020] Preferably, the combustion sample is absorbent cotton.

[0021] Compared with the related art, the present invention has achieved the following technical effects:

[0022] 1) After the positioning unit locates the combustion sample, the ignition unit ignites the combustion sample, and then the combustion process data can be recorded by the recording unit and transmitted to the analysis unit for summary analysis.

[0023] When the gas injection unit supplies combustion-supporting gas to the combustion space, it can adjust the fire intensity through the combustion-supporting gas to simulate different gas circulation conditions, thus introducing the variable of gas circulation. When the gas injection unit supplies combustible gas to the combustion space, it can trigger an explosion when the combustible gas reaches a certain concentration, thus simulating the environmental conditions of a gas leak, thus introducing the variable of whether a gas leak has occurred.

[0024] Therefore, the present invention can explore the influence of changes in the gas circulation environment and whether gas leakage occurs on the combustion process through the provision of the gas injection unit.

[0025] 2) In the preferred embodiment of the present invention, the position of the grille is changed by the position adjustment component, thereby changing the position of the combustion sample sandwiched between the two grilles. The variable of the position of the ignition position can be introduced to explore the influence of the position of the ignition position on the combustion process.

[0026] 3) In a preferred embodiment of the present invention, by distributing multiple combustion samples in a discrete manner and combining them with high-speed camera photography, the ignition sequence of each combustion sample can be clearly observed, thereby facilitating the study of the direction of fire spread between different combustible materials. In actual use, combustion samples can be omitted near some nodes to introduce the variable of sample spacing, thereby exploring the impact of changes in the spacing between two adjacent combustion samples on the combustion process.

[0027] 4) In the preferred embodiment of the present invention, by selecting ignition heads with different firing positions, the variable of fire location can be introduced. This allows the influence of fire location on the combustion process to be investigated while maintaining the same layout of the combustion sample (identical to the fire scene). By combining simulation results with actual fire scene data, the true fire location can be analyzed.

[0028] 5) In the preferred embodiment of the present invention, since the second end of the gas injection pipeline faces the ground, the roughly horizontal ground can be used to achieve uniform dispersion of the airflow on the one hand, and the airflow can be prevented from flowing directly to the vicinity of the combustion position on the other hand.

[0029] 6) In a preferred embodiment of the present invention, the gas ejected from the second end of the gas injection pipeline contains tracer colored smoke or ultrafine non-combustible colored particles with a particle size of less than 30 μm. By comparing the color concentration of the colored smoke or the distribution of the colored particles in different areas of the combustion space, it is possible to determine whether the gas supplied by the gas injection unit is evenly distributed within the combustion space.

[0030] 7) In a preferred embodiment of the present invention, the air flow direction within the combustion space can be adjusted by adjusting the installation position of the blower; the air flow velocity within the combustion space can be adjusted by adjusting the blower's rotational speed. Furthermore, the blower can quickly exhaust toxic gases after combustion is complete, allowing operators to enter the combustion space and inspect for burn marks. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 Schematic diagram of a gas diffusion fire inversion test device based on combustion traces according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of a gas diffusion fire inversion test device based on combustion traces according to an embodiment of the present invention, viewed from above.

[0034] In the figure: 1-mass flow meter; 2-gas cylinder; 3-pressure reducing valve; 4-computer; 5-remote control; 6-blowing device; 7-high-speed camera; 8-gas injection pipeline; 9-flame arrester; 10-column; 11-position adjustment component; 12-grid; 13-gas concentration sensor; 14-speed and temperature synchronous measurement sensor; 15-ignition head; 16-combustion sample. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] The purpose of the present invention is to provide a gas diffusion fire inversion test device based on combustion traces, so as to provide a basis for fire inversion through simulation testing.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Reference Figure 1 、 Figure 2 , this embodiment provides a gas diffusion fire inversion test device based on combustion traces, including a positioning unit, an ignition unit, a gas injection unit, a recording unit and an analysis unit.

[0039] The positioning unit includes a positioning assembly, which includes two positioning members and a plurality of clamping members. The clamping members clamp the two positioning members so that the two positioning members can sandwich the combustion sample 16. The positioning member is a grid 12 that provides a mesh as a gas flow channel.

[0040] The ignition unit is used to ignite the combustion sample 16. The gas injection unit is used to provide combustible gas or combustion-supporting gas to the combustion space. The recording unit is used to record gas diffusion, remote ignition, and reverse combustion processes. The analysis unit is electrically connected to the recording unit and is used to receive and analyze combustion process data.

[0041] The recording unit includes a high-speed camera 7, a synchronous velocity and temperature measurement sensor 14, and a gas concentration sensor 13 to simultaneously collect images, gas flow velocity, gas temperature, and gas concentration data. Multiple synchronous velocity and temperature measurement sensors 14 and gas concentration sensors 13 are uniformly arranged.

[0042] In the absence of ambient wind interference, the gas diffusion process is dominated by natural convection, making its path and velocity highly predictable. Consequently, sensor layout can be significantly simplified: the number of gas concentration sensors 13 can be significantly reduced, with placement limited to key areas such as the combustion sample's axis of symmetry, the direction of leak outlet radiation, and the flame's reverse path. The number of simultaneous velocity and temperature measurement sensors 14 can also be significantly reduced, with these sensors concentrated in areas with a high probability of flame spread.

[0043] Critical diffusion paths are determined through preliminary experiments. Specifically, before formal testing, preliminary experiments involve conducting ignition tests based on parameters such as leakage volume, wind direction, fire location, and combustion sample spacing specified under experimental conditions. Recording units record gas diffusion, remote ignition, and reverse combustion processes, recording gas diffusion and reverse combustion paths. Based on this preliminary data, the areas where gas and flames most frequently pass through are identified and used as key areas for sensor placement in subsequent experiments.

[0044] The time required for valid measurement of a single parameter is preferably less than 3 seconds. In particular, the gas concentration sensor 13 is preferably an optical gas concentration sensor that requires a relatively short time for valid measurement.

[0045] The recording unit can record the temperature, concentration and image of the flammable gas diffusion process before combustion, the long-distance ignition and flame spreading from the ignition source to the edge, the flame back from the edge to the leak port, and the flame continuing to burn at the leak port.

[0046] The working principle of the gas diffusion fire inversion test device based on combustion traces in this embodiment (hereinafter referred to as the fire inversion test device) is as follows:

[0047] After the positioning unit locates the combustion sample 16, the ignition unit ignites the combustion sample 16, and then the combustion process data can be recorded by the recording unit and transmitted to the analysis unit for summary analysis.

[0048] The key to this fire inversion test device lies in how to introduce variables to simulate different fire environments and explore the impact of the introduction of variables on the combustion process, thereby providing an inversion basis for various fire scenarios.

[0049] When the gas injection unit provides combustion-supporting gas to the combustion space, the fire intensity can be adjusted by the combustion-supporting gas to simulate different gas circulation conditions, that is, the variable of gas circulation condition is introduced.

[0050] When the gas injection unit provides combustible gas to the combustion space, it can trigger an explosion when the combustible gas reaches a certain concentration to simulate the environmental conditions of gas leakage, that is, introduce the variable of whether gas leakage occurs.

[0051] Therefore, the above embodiment can explore the influence of changes in the gas circulation environment and whether there is gas leakage on the combustion process by setting the gas injection unit.

[0052] As a possible example, in this embodiment, the positioning unit further includes a column 10 and a position adjustment assembly 11. The position adjustment assembly 11 is mounted on the column 10 and connected to the grille 12 to adjust at least one of the height position and the horizontal position of the grille 12.

[0053] By changing the position of the grid 12 through the position adjustment component 11, and then changing the position of the combustion sample 16 sandwiched between the two grids 12, the variable of the position of the ignition position can be introduced to explore the influence of the position of the ignition position on the combustion process.

[0054] Exemplarily, the portion of the position adjustment component 11 connected to the grid 12 has a melting point of not less than 1000° C.; the melting point of the grid 12 is not less than 1100° C. to avoid melting and deformation.

[0055] It should be noted that if there is only one positioning component, only the spread of fire on a plane can be simulated. If you need to study the spread of fire in space, you can choose to set the number of positioning components to multiple, and place them at different heights and horizontal positions.

[0056] As a possible example, in this embodiment, the meshes of the upper and lower grilles 12 are positioned opposite each other. There are multiple combustion samples 16 arranged at intervals, and each combustion sample 16 is arranged between nodes of two grilles 12.

[0057] By distributing the plurality of combustion samples 16 in a discrete manner and combining the shooting with the high-speed camera 7 , the ignition sequence of each combustion sample 16 can be clearly observed, thereby facilitating the study of the direction of fire spread between different combustibles.

[0058] In actual use, it is not necessary to arrange the combustion sample 16 near every node of the grid 12. The combustion sample 16 may be arranged without being arranged near some nodes to introduce the variable of the spacing between the combustion samples 16, so as to explore the impact on the combustion process when the spacing between two adjacent combustion samples 16 changes.

[0059] As a possible example, in this embodiment, the ignition unit includes a plurality of ignition heads 15 , which are evenly distributed and individually controlled to adjust the ignition position.

[0060] By selecting different positions for the ignition heads 15, the variable of fire location can be introduced. This allows the influence of fire location on the combustion process to be investigated while maintaining the layout of the combustion sample 16 (identical to the layout at the fire scene). By combining simulation results with actual fire scene data, the true fire location can be analyzed.

[0061] For example, the ignition head 15 is mounted on an arc igniter, and remote ignition control is performed via a remote controller 5. The remote control diameter of the remote controller 5 is not less than 10m to ensure the safety of the operator.

[0062] For example, uniform distribution of the multiple ignition heads 15 refers to uniform distribution along the circumference to adjust the ignition position along the circumference. The multiple ignition heads 15 are distributed radially in multiple circles to adjust the ignition position along the radial direction. The central angle between two adjacent ignition heads 15 on the same circumference is 45°, and the spacing between two adjacent ignition heads 15 on the same diameter is no less than 10 cm to prevent adjacent ignition heads 15 from interfering with each other.

[0063] As a possible example, in this embodiment, the gas injection unit includes a gas cylinder 2, a pressure reducing valve 3, a gas injection pipeline 8, a mass flow meter 1, and a flame arrester 9. The pressure reducing valve 3 is mounted at the mouth of the gas cylinder 2. The gas injection pipeline 8 has a first end connected to the pressure reducing valve 3 and a second end extending to the combustion space. The mass flow meter 1 and the flame arrester 9 are mounted on the gas injection pipeline 8.

[0064] The high-pressure gas stored in gas cylinder 2 is reduced in pressure by pressure reducing valve 3 and then enters gas injection pipeline 8. It is then transported to the combustion space through mass flowmeter 1 and flame arrester 9. Mass flowmeter 1 records the gas flow rate, assisting the operator in accurately controlling the amount of gas released from gas cylinder 2, avoiding the introduction of multiple variables and maintaining a single variable. Flame arrester 9 prevents flashback caused by negative pressure in gas cylinder 2.

[0065] For example, the mass flow meter 1 has an accuracy of at least 1.67×10 -5 m 3 / s (under standard conditions of temperature 273.15K and pressure 101.325kPa), the mass flowmeter 1 has preset parameters to adjust the flow rate of the gas output from the gas cylinder 2.

[0066] As a possible example, in this embodiment, the second end of the gas injection pipeline 8 is located on the lower side of the two grids 12, and is vertically downward or obliquely downward, so that the gas supplied by the gas injection unit is used as ambient gas, eliminating the influence of the initial velocity of gas leakage on gas diffusion, distant fire, and combustion process in a miniature experimental environment.

[0067] Since the second end of the gas injection pipeline 8 faces the ground, on the one hand, the substantially horizontal ground can be used to achieve uniform dispersion of the airflow, and on the other hand, the airflow can be prevented from directly flowing to the vicinity of the combustion position.

[0068] Exemplarily, the portion of the gas injection line 8 located within the combustion space includes a first vertical segment, a horizontal segment, and a second vertical segment. The first vertical segment is located outside the positioning assembly, meaning it does not pass through the mesh of the grid 12. The lower end of the first vertical segment is connected to the first end of the horizontal segment via a 90-degree elbow. The second end of the horizontal segment is located at the center below the positioning assembly and is connected to the upper end of the second vertical segment via a 90-degree elbow.

[0069] The above layout enables the gas injection pipeline 8 to bypass the positioning assembly from the outside, which not only ensures that the gas provided by the gas injection unit diffuses outward in a central radiation manner, but also reduces the impact of combustion and explosion processes on the gas injection pipeline 8.

[0070] For example, the inner diameter of the nozzle of the gas injection pipeline 8 does not exceed 20 mm. The gas injection pipeline 8 is an explosion-proof pipe with a minimum pressure resistance of 0.85 MPa.

[0071] As a possible example, in this embodiment, the gas ejected from the second end of the gas injection pipeline 8 contains tracer colored smoke or ultrafine non-combustible colored particles with a particle size of less than 30 μm. By comparing the color concentration of the colored smoke in different areas of the combustion space, it can be determined whether the gas supplied by the gas injection unit is evenly distributed within the combustion space.

[0072] The colored smoke can be pre-stored in the gas cylinder 2 or introduced into the second end of the gas injection pipeline 8 in an ejection manner.

[0073] As a possible example, in this embodiment, the gas diffusion fire inversion test device based on combustion traces further includes a blowing device 6 for adjusting the airflow direction in the combustion space. Exemplarily, the blowing device 6 can be a fan or a blower.

[0074] By adjusting the installation position of the blowing device 6, the variable of the air flow direction in the combustion space can be introduced; by adjusting the rotation speed and wind direction of the blowing device 6, the variables of the air flow speed and flow direction in the combustion space can be introduced.

[0075] In addition, the blowing device 6 can also quickly discharge toxic gases after the combustion is completed, so that operators can enter the combustion space to check the combustion traces on site.

[0076] As a possible example, in this embodiment, the combustible gas provided by the gas injection unit can be quickly and accurately measured in seconds using an optical gas concentration sensor, and can meet the lower explosion limit in air of not less than 2% to avoid premature explosion, preferably methane or propane.

[0077] Exemplarily, the combustible gas provided by the gas injection unit is further preferably methane, which has a lower explosion limit of 5.3% in air.

[0078] As a possible example, in this embodiment, the combustion sample 16 is determined according to the actual fire scene. The experiment recommends using absorbent cotton, which is solid at room temperature and can reflect carbonization and burning marks after encountering fire, avoiding the production of toxic gases and causing environmental damage.

[0079] As a possible example, in this embodiment, the high-speed camera 7 is located at the top window of the combustion space, with the lens facing the positioning assembly, and can capture the traces of combustion of the combustion sample 16 after combustion. The focal length range is 10mm to 35mm, the frame rate is not less than 1000 frames per second, and the resolution is not less than 1920x1080 pixels.

[0080] The above parameters are selected to ensure that the high-speed camera 7 can capture subtle changes in the rapid combustion process, so that researchers can observe the details and dynamic behavior of the flame.

[0081] As a possible example, in this embodiment, the height of the pillars 10 is no less than 3 meters. The grille 12 is 1.1 meters long, 0.8 meters wide, and 0.01 meters thick. The number of meshes in the grille 12 is 7×10, and the meshes are squares with a side length of 0.1 meters. The number of nodes in the grille 12 is 6×9.

[0082] As a possible example, in this embodiment, the gas concentration sensor 13 has a range of 0 to 100% and an accuracy of 0.1%. There are 16 gas concentration sensors 13, distributed in a rectangular shape directly above the grid 12, with the center of the rectangle being the center of the grid 12. The rectangle has a side length of 1 m x 0.7 m, with five gas concentration sensors 13 distributed along each side of the rectangle.

[0083] It is not difficult to obtain that the outline of the distribution rectangle of the gas concentration sensor 13 in the top view direction is close to the edge area of the grille (the length and width of the two are similar), and the actual combustion range is mainly the range covered by the grille. Therefore, the edge distribution method of the gas concentration sensor 13 can reduce the impact on the combustion process.

[0084] As a possible example, in this embodiment, the analysis unit is a computer 4. The computer 4 has built-in image analysis software, gas concentration analysis software, and temperature analysis software to analyze the image data captured by the high-speed camera 7, the concentration data monitored by the gas concentration sensor 13, and the temperature data monitored by the speed and temperature synchronous measurement sensor 14, respectively.

[0085] As a possible example, in this embodiment, the speed and temperature synchronous measurement sensor 14 uses a K-type armored thermocouple with a temperature measurement range of -200°C to 1300°C. There are eight speed and temperature synchronous measurement sensors 14, evenly distributed along the circumference, with the center of the circle being the center of the grid 12.

[0086] One method of using the fire inversion test device (the actual method of use is not limited to this) is as follows:

[0087] Step 1: Fix the combustion sample 16 and adjust the height of the positioning component to a preset height position and a horizontal position.

[0088] Step 2: Adjust the mass flow meter 1 to the target flow rate;

[0089] Step 3: The gas injection unit starts injecting gas. When the gas concentration sensor 13 shows that the concentration of the injected gas reaches a preset value, the high-speed camera 7 starts recording and the ignition unit starts ignition.

[0090] Step 4: After the flame is formed, the timing starts. When the preset burning time is reached, the gas injection unit stops injecting gas and waits for the remaining flame to go out.

[0091] Step 5: Turn on the blowing device 6 and turn off the blowing device 6 after a period of time.

[0092] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A gas diffusion fire inversion test device based on combustion traces, characterized in that: include: The positioning unit includes a positioning assembly, wherein the positioning assembly includes two positioning members and a plurality of clamping members; the clamping members clamp and fix the two positioning members so that the two positioning members can clamp the combustion sample in the middle; the positioning member is a grid to provide a mesh as a gas flow channel; an ignition unit, for igniting the combustion sample; A gas injection unit, used to provide combustible gas or combustion-supporting gas to the combustion space; Recording unit, used to record gas diffusion, remote fire, and reverse combustion processes; an analysis unit, electrically connected to the recording unit, for receiving and analyzing combustion process data; The recording unit includes a high-speed camera, a speed and temperature synchronous measurement sensor and a gas concentration sensor to simultaneously collect images, gas flow velocity, gas temperature and gas concentration data; the number of the speed and temperature synchronous measurement sensor and the gas concentration sensor is multiple and evenly arranged.

2. The gas diffusion fire inversion test device based on combustion traces according to claim 1 is characterized in that: The positioning unit further includes a column and a position adjustment component; the position adjustment component is installed on the column and connected to the grille to adjust at least one of the height position and the horizontal position of the grille.

3. The gas diffusion fire inversion test device based on combustion traces according to claim 1 is characterized in that: The meshes of the upper and lower grilles are positioned opposite each other; the number of the combustion samples is multiple and they are arranged at intervals, and each combustion sample is arranged between the nodes of the two grilles.

4. The gas diffusion fire inversion test device based on combustion traces according to claim 3 is characterized in that: The ignition unit includes a plurality of ignition heads, which are evenly distributed and individually controlled to adjust the ignition position.

5. The gas diffusion fire inversion test device based on combustion traces according to claim 1 is characterized in that: The gas injection unit includes a gas cylinder, a pressure reducing valve, a gas injection pipeline, a mass flow meter and a flame arrester; the pressure reducing valve is installed at the bottle mouth of the gas cylinder; the first end of the gas injection pipeline is connected to the pressure reducing valve, and the second end extends to the combustion space; the mass flow meter and the flame arrester are installed on the gas injection pipeline.

6. The gas diffusion fire inversion test device based on combustion traces according to claim 5 is characterized in that: The second end of the gas injection pipeline is located at the lower side of the two grids and is vertically downward or obliquely downward.

7. The gas diffusion fire inversion test device based on combustion traces according to claim 5 is characterized in that: The gas ejected from the second end of the gas injection pipeline contains colored smoke or ultra-fine non-combustible colored particles with a particle size of less than 30 μm for tracing.

8. The gas diffusion fire inversion test device based on combustion traces according to claim 1 is characterized in that: It also includes a blowing device for adjusting the direction of airflow in the combustion space.

9. The gas diffusion fire inversion test device based on combustion traces according to claim 1 is characterized in that: The combustible gas provided by the gas injection unit is methane or propane.

10. The gas diffusion fire inversion test device based on combustion traces according to claim 1, characterized in that: The combustion sample is absorbent cotton.

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