An experimental system and method for simulating smoke spread in tunnel fire

Abstract

The present invention discloses an experimental system and method for simulating the spread of smoke in a tunnel fire, comprising a water reservoir for containing an environmental fluid and an image sampling device arranged outside the water reservoir, wherein the water reservoir is made of a transparent material, a transparent tunnel model is arranged in the water reservoir, both ends of the tunnel model have openable and closable openings, a chamber for circulating fluid is formed inside the tunnel model, and a fluid supply hole for injecting a dyed working fluid is arranged on the tunnel model; the present invention simulates the spread of smoke in a tunnel fire by using a clean working fluid, thereby reducing the danger of the experiment and the pollution to the environment, improving the flow visibility in the experiment, and combining image processing to realize the global interference-free measurement of key parameters of the flow field, thereby obtaining the spatiotemporal distribution of the density and velocity of pollutants, and improving the accuracy of the experimental data.

Description

Technical Field

[0001] The invention relates to the field of tunnel fire safety experiments, and in particular to an experimental system and method for simulating smoke spread in a tunnel fire. Background Art

[0002] Tunnels are very common in modern production and life. They are long and narrow and are semi-enclosed gray box environments. Once a fire occurs in a tunnel or pollutants such as methane leak, high-temperature smoke or harmful gases will spread rapidly along the tunnel ceiling under the action of buoyancy, forming a ceiling jet, which seriously threatens the safety of people in the tunnel. The spread speed, thickness, temperature, and density distribution of the ceiling jet have a significant impact on the evacuation of personnel, and it is necessary to conduct in-depth research.

[0003] At present, when studying the spread of harmful gases such as smoke or methane in tunnel fires, a scaled-down tunnel is usually built and corresponding combustion or methane leakage experiments are carried out. However, this research method also has disadvantages: (1) It is somewhat dangerous; (2) The visibility of the flow field is poor, the number of sensors arranged is limited, and it is difficult to obtain the velocity and density distribution in the entire flow field, and the sensors will interfere with the flow field; (3) The heat release rate of the fire source in the combustion experiment is affected by the fuel combustion efficiency, and its quantification has certain uncertainties. Summary of the invention

[0004] The purpose of the present invention is to provide an experimental system and method for simulating the spread of smoke in a tunnel fire. The experimental system and method simulate the spread of smoke in a tunnel fire by using a working fluid and simulate the ambient air by using clean water, thereby reducing the risk of the experiment, and using image processing to achieve global interference-free measurement of the density and spread speed of pollutants in the tunnel, thereby improving the accuracy of the experimental data.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] An experimental system for simulating the spread of smoke in a tunnel fire comprises a water reservoir for containing an environmental fluid and an image sampling device arranged outside the water reservoir, wherein the water reservoir is made of a transparent material, a transparent tunnel model is arranged in the water reservoir, both ends of the tunnel model have openable and closable openings, a chamber for circulating fluid is formed inside the tunnel model, and a liquid supply hole for injecting a dyed working fluid is arranged on the tunnel model. During the experiment, the environmental fluid fills the water reservoir and both ends of the tunnel model are opened, the environmental fluid fills the tunnel model, and then the dyed working fluid is injected into the chamber of the tunnel model through the liquid supply hole to simulate the spread of smoke in a fire, and the flow of the dyed working fluid is recorded in real time by the image sampling device.

[0007] Furthermore, a light source is arranged outside the water reservoir to supplement the lighting of the tunnel model.

[0008] Furthermore, the light source is arranged outside the rear side of the water reservoir, and is a backlight panel that can emit scattered light with stable light intensity, and the size of the backlight panel is equal to the size of the rear wall of the water reservoir.

[0009] Furthermore, the image sampling device is arranged outside the front side of the water reservoir, and is a camera.

[0010] Furthermore, the liquid supply hole is arranged at the top or bottom of the tunnel model, and the liquid supply hole is connected to the liquid supply device outside the water reservoir through a pipeline.

[0011] Furthermore, the liquid supply device is arranged outside the water reservoir, and includes a peristaltic pump and a liquid storage tank connected to the input end of the peristaltic pump. The output end of the peristaltic pump is provided with a valve, and the valve is connected to the liquid supply hole on the tunnel model through a pipeline.

[0012] An experimental method for simulating smoke spread in a tunnel fire comprises the following steps:

[0013] Step 1, calibration: clean water is injected into the reservoir, the tunnel model is sealed, and pictures of the dye working fluid with different concentrations are taken. The pictures are converted into grayscale images, and the grayscale values ​​at the same pixel of all grayscale images are fitted with polynomials to obtain a curve of the grayscale value at each pixel versus the dye concentration, and the calibration is completed;

[0014] Step 2, obtain the working fluid flow diagram:

[0015] (1) The tunnel model is placed in a water reservoir, with the openings at both ends opened, and the chamber inside the tunnel model is filled with clean water; (2) The dyed working fluid is injected through the liquid supply hole set at the bottom or top of the tunnel model, and the working fluid forms a ceiling jet in the tunnel, and the flow diagram of the dyed working fluid at different times is obtained by taking pictures;

[0016] Step 3, analyze the image:

[0017] (1) converting the dye working fluid flow diagram into a grayscale diagram, and obtaining a distribution diagram of the dye concentration in the tunnel model at different times according to the grayscale value at each pixel point and the calibration curve at each pixel point obtained in step 1;

[0018] (2) Based on the dye concentration distribution in the tunnel model, a distribution model of the working fluid's reduced gravitational acceleration is constructed;

[0019] (3) Detecting the distribution diagram of dye concentration to obtain the spreading speed of the working fluid;

[0020] (4) Construct the scale of reduced gravity acceleration and spreading velocity between the experimental model and the full-scale tunnel prototype;

[0021] (5) Use the scale to obtain the distribution of the reduced gravity acceleration and spreading velocity of the ceiling jet in the actual tunnel.

[0022] Furthermore, the step 2 of obtaining the working fluid flow diagram comprises the following steps:

[0023] (1) The tunnel model is placed in a water reservoir with both ends open, and the chamber inside the tunnel model is filled with clean water;

[0024] (2) The dyed working fluid is injected through the liquid supply hole set at the bottom or top of the tunnel model. The working fluid forms a ceiling jet in the tunnel, and the flow diagram of the dyed working fluid at different times is obtained by taking pictures.

[0025] Furthermore, in step 3, detecting the distribution diagram of the dye concentration comprises the following steps:

[0026] (1) Draw a vertical line parallel to the tunnel ceiling along the distribution diagram of dye concentration, and extract all pixel points at this height;

[0027] (2) Based on the distribution model of the reduced gravitational acceleration, the time-varying reduced gravitational acceleration of all pixel points on the vertical line is determined, and the corresponding change graph is obtained, thereby obtaining the transient displacement of different fluid micro-groups on the vertical line and the spreading speed of the working fluid.

[0028] Furthermore, in step 3, all the oblique lines representing the transient displacement on the variation diagram are extracted by Hough transform, and the average value of the slopes of all the oblique lines represents the spreading speed of the working fluid at the height.

[0029] Compared with the prior art, the technology of the present invention has the following advantages:

[0030] The experimental system and method of the present invention utilize clean water to simulate ambient air, and utilize working fluid to simulate the spread of fire smoke. There is no combustion, toxic smoke, methane or other dangerous gases in the experiment, thereby reducing the risk of the experiment and reducing environmental pollution. The buoyancy flux used to simulate the fire source or pollution source can be accurately controlled by a peristaltic pump. Since the working fluid is dyed, the flow conditions in the flow field can be intuitively observed without the need to arrange a large number of sensors. Combined with image processing, global and non-interference measurement of key flow field parameters can be achieved, and the spatiotemporal distribution of pollutant density and velocity can be obtained, thereby improving the accuracy of experimental data. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Figure 1 The invention is a schematic diagram of the structure of an experimental system for simulating the spread of smoke in a tunnel fire;

[0033] Figure 2Schematic diagram of the tunnel model with multiple closed injections during the calibration process;

[0034] Figure 3 It is a curve diagram of the change of gray value at a single pixel point with the dye concentration;

[0035] Figure 4 Color the working fluid flow diagram at different times in the tunnel model;

[0036] Figure 5 It is the distribution diagram of reduced gravity acceleration in the tunnel model;

[0037] Figure 6 It is a distribution diagram with a vertical line z=h minus the gravitational acceleration;

[0038] Figure 7 For detection Figure 6 A graph showing the change of the reduced gravitational acceleration over time at all pixels at z=h.

[0039] Markings on the accompanying drawings: 1-water reservoir, 2-tunnel model, 3-liquid supply hole, 4-image sampling device, 5-light source, 6-peristaltic pump, 7-liquid storage tank, 8-valve. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. The description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] See also Figure 1 The present invention provides an experimental system for simulating the spread of smoke in a tunnel fire. The experimental device includes a water reservoir 1 and a tunnel model 2 fixedly arranged in the water reservoir 1 and into which a fluid can pass; the water reservoir 1 and the tunnel model 2 are both made of transparent organic glass, wherein the water reservoir 1 has a rectangular side wall and a bottom wall, and a pool opening for the tunnel model 2 to be placed in the water reservoir 1, and the tunnel model 2 is detachably fixed in the water reservoir 1 by a bracket.

[0042] Specifically, the tunnel model 2 is a rectangular parallelepiped with openable and closable openings at both ends, and a chamber for fluid flow is formed inside the tunnel model; liquid supply holes 3 for simulating the location of fire sources or leakage pollution sources are arranged at the top and bottom of the tunnel model, and the liquid supply holes 3 are connected to the liquid supply device outside the water reservoir 1 through a pipeline; during the experiment, the environmental fluid fills the water reservoir 1 and the openings at both ends of the tunnel model 2 are opened, the environmental fluid fills the tunnel model, and the liquid supply device transports the dyed working fluid to the tunnel model 2, and the environmental fluid simulates the spread of fire smoke in the chamber of the tunnel model, and an image sampling device 4 is arranged on the front side of the water reservoir 1 to record the fluid flow in the chamber of the tunnel model 2, and a light source 5 is arranged on the back side of the water reservoir 1 to supplement the light of the tunnel model 2. The light source 5 is the only light source in the entire experimental environment to ensure that the image sampling device 4 obtains a clear fluid flow image.

[0043] In this embodiment, the liquid supply device is arranged outside the water reservoir 1, and includes a peristaltic pump 6 and a liquid storage tank 7 connected to the input end of the peristaltic pump 6. The output end of the peristaltic pump 6 is provided with a valve 8, and the valve 8 is connected to the liquid supply hole 3 on the tunnel model 2 through a pipeline; the peristaltic pump 6 extracts the dyeing working fluid stored in the liquid storage tank 7. After opening the valve, the dyeing working fluid flows along the pipeline and flows from the liquid supply hole 3 into the chamber inside the tunnel model 2. The rate of releasing the dyeing working fluid can be controlled by adjusting the rotation speed of the peristaltic pump 6.

[0044] Preferably, the image sampling device 4 is arranged on the outside of the front side of the water reservoir 1. It is a camera, which records the fluid flow images at different times through the camera. Compared with the existing solution of arranging sensors in the tunnel, this method can reduce the interference to the fluid flow and improve the accuracy of the experimental data.

[0045] Preferably, the light source 5 is arranged on the outside of the rear side of the water reservoir 1. It is a backlight panel that can scatter light with constant light intensity. The size of the backlight panel is equal to the size of the rear wall of the water reservoir to provide uniform and comprehensive fill light to the tunnel model 2 and improve the clarity of the fluid flow image.

[0046] The present invention also provides an experimental method for simulating the spread of smoke in a tunnel fire, comprising the following steps:

[0047] Step 1, Calibration:

[0048] (1) Fill the reservoir with clean water;

[0049] (2) The tunnel model was sealed and filled with clean water, then placed in a water reservoir and photographed to obtain picture P0;

[0050] (3) The secondary tunnel model was sealed and injected with liquid. The tunnel model was fixed and a dye working fluid with a dye concentration of 0.01 g / L was injected. Picture P1 was obtained by taking a picture.

[0051] (4) performing multiple closed water injections into the tunnel model according to the above operation (3), and gradually increasing the dye concentration of the dyeing working fluid to obtain r images;

[0052] (5) All images are converted into grayscale images, and each image has m × n grayscale values, where m and n are the number of rows and columns of pixels in the tunnel model area in the image (see Figure 2 );

[0053] (6) Perform polynomial fitting on the grayscale values ​​at the same pixel of all grayscale images to obtain a curve of the grayscale value at the pixel as a function of dye concentration (see Figure 3 ), a total of m×n calibration curves are obtained, and the calibration is completed;

[0054] Step 2, obtain the fluid flow diagram:

[0055] (1) The tunnel model is fixed in the water reservoir, with both ends open, and the chamber inside the tunnel model is filled with clean water; (2) The dyed working fluid is injected through the liquid supply hole set at the bottom or top of the tunnel model, and the working fluid forms a ceiling jet in the tunnel. The flow diagram of the dyed working fluid at different times is obtained by taking pictures (see Figure 4 );

[0056] Step 3, analyze the image:

[0057] (1) Convert the dye working fluid flow diagram into a grayscale diagram, and obtain the dye concentration C in the tunnel model at different times according to the grayscale value at each pixel and the calibration curve at each pixel obtained in step 1. d / C d0 The distribution diagram (see Figure 5 );

[0058] (2) The initial density of the dyeing working fluid is ρ0, and the initial dye concentration is C d0 , according to the following formula:

[0059]

[0060]

[0061] Where m0 is the mass of the working fluid; m d0 is the mass of the dye; V0 is the volume of the working fluid; the working fluid absorbs clean water during the flow process, and its density and the concentration of the dye change accordingly:

[0062]

[0063]

[0064] Where V1 is the volume of clean water sucked, ρ is the density of the working fluid after the clean water is sucked, C d is the concentration of the dye after the water is entrained; since the total mass of the dye remains unchanged during the flow process, combining equations (2) and (4) yields:

[0065] (V1+V0)C d =C d0 V0 (5)

[0066] Combining equation (1), equation (3) and equation (5), we can get:

[0067]

[0068] After sorting, we can get:

[0069]

[0070] In formula (7), Δρ0 and Δρ are the density differences between the working fluid and the clean water before and after dilution, respectively. Since the working fluid reduced gravity acceleration is defined as g' = gΔρ / ρ water , the relationship between the reduced gravity acceleration of the working fluid and the dye concentration can be obtained, g' / g0'=C d / C d0 ; The distribution of dye concentration obtained by experiment and image processing can be converted into the distribution of key parameters of ceiling jet minus gravity acceleration through this formula;

[0071] (3) Along Figure 5 Draw a vertical line z=h parallel to the tunnel ceiling, and extract all the pixels at this height in the tunnel (see Figure 6 );

[0072] (4) Based on the spatiotemporal distribution of the reduced gravitational acceleration, determine Figure 6 The reduced gravity acceleration at all pixel points at z = h changes with time to obtain a change graph (see Figure 7 ), there are multiple oblique lines in the variation diagram, representing the transient displacement of different fluid micro-groups at the height; all oblique lines representing the transient displacement in the variation diagram are extracted by Hough transform, and the average slope of all oblique lines represents the spreading speed of the working fluid at the height; by changing the height h, the speed at different heights can be obtained;

[0073] (5) The distribution of key parameters such as the reduced gravity acceleration and propagation velocity obtained by the experimental system and method needs to be converted into the magnitude of the reduced gravity acceleration and propagation velocity in the full-scale tunnel through the similarity criterion. This conversion process complies with the following criteria; according to the Froude number formula:

[0074]

[0075] Where Fr is the Froude number, u is the characteristic velocity, g' is the reduced gravitational acceleration, and H is the characteristic length. The buoyancy flux is a key parameter of the buoyancy-driven flow. The buoyancy flux of the working fluid in the liquid experimental system can be calculated by the following formula:

[0076] B=g'Q (9)

[0077] In the formula, B is the buoyancy flux of the working fluid per unit width of the tunnel, and Q is the flow rate of the working fluid per unit width of the tunnel. If a harmful gas leakage accident occurs in the tunnel, its buoyancy flux can be directly calculated by formula (9); if a fire accident occurs in the tunnel, the buoyancy flux of the fire source can be calculated by the following formula:

[0078]

[0079] Where E is the convective heat release power of the fire source, C p is the specific heat of air, ρ a and T a are the ambient air density and temperature, respectively; W is the tunnel width; the scale of the buoyancy flux in this experimental system and the full-scale tunnel is n B =B s / B f are known, the subscripts s and f represent the parameters in the experiment and prototype respectively; during the experiment, it is necessary to ensure that Fr s Number and prototype Fr f The numbers are equal, so we can construct the scale of the reduced gravity acceleration in the experiment and the prototype:

[0080]

[0081] Where n L Represents the scale of length. Combining equation (8) and equation (11), we can get the scale of speed n V .

[0082] n V =V s / V f =n B 1 / 3 (12)

[0083] (6) Use the scale to obtain the distribution of key parameters such as the reduced gravity acceleration and spreading velocity of the ceiling jet in the full-scale tunnel.

[0084] In this experimental method, when the dye working fluid is ethanol or hot water (with a lower density than pure water), the valve connected to the liquid supply hole at the top of the tunnel model through a pipe is closed, and the liquid is injected from the liquid supply hole at the bottom of the tunnel model; when the dye fluid is salt water (with a higher density than pure water), the valve connected to the liquid supply hole at the bottom of the tunnel model through a pipe is closed, and the liquid is injected from the liquid supply hole at the top of the tunnel model.

[0085] The above embodiments of the present invention are not intended to limit the protection scope of the present invention, and the implementation modes of the present invention are not limited thereto. All other various forms of modifications, replacements or changes made to the above structures and methods of the present invention based on the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, should all fall within the protection scope of the present invention.

Claims

1. An experimental method for simulating the spread of smoke in a tunnel fire, using an experimental system for simulating the spread of smoke in a tunnel fire, the experimental system comprising a water reservoir for containing an environmental fluid and an image sampling device arranged outside the water reservoir, the water reservoir is made of a transparent material, a transparent tunnel model is arranged in the water reservoir, both ends of the tunnel model have openable and closable openings, the interior of the tunnel model forms a chamber for circulating fluid, and the tunnel model is provided with a liquid supply hole for injecting a dyed working fluid, characterized in that: The following steps are involved: Step 1, calibration: close the openings at both ends of the tunnel model to seal the tunnel model, inject clean water into the reservoir, inject clean water into the tunnel model, take pictures, drain the clean water from the tunnel model, and take pictures of injecting dye working fluids of different concentrations into the tunnel model, convert the pictures into grayscale images, perform polynomial fitting on the grayscale values ​​at the same pixel point of all grayscale images, obtain a curve diagram of the grayscale value at each pixel point versus dye concentration, and the calibration is completed; Step 2, obtaining a working fluid flow diagram; Step 3, analyze the image: (1) converting the dye working fluid flow diagram into a grayscale diagram, and obtaining a distribution diagram of the dye concentration in the tunnel model at different times according to the grayscale value at each pixel point and the calibration curve at each pixel point obtained in step 1; (2) Based on the dye concentration distribution in the tunnel model, a distribution model of the working fluid's reduced gravitational acceleration is constructed; The initial density of the dyeing working fluid is ρ0, and the initial dye concentration is C d0 , according to the following formula: Where m0 is the mass of the working fluid; m d0 is the mass of the dye; V0 is the volume of the working fluid; the working fluid absorbs clean water during the flow process, and its density and the concentration of the dye change accordingly: Where V1 is the volume of clean water sucked, ρ is the density of the working fluid after the clean water is sucked, C d is the concentration of the dye after the water is entrained; since the total mass of the dye remains unchanged during the flow process, combining equations (2) and (4) yields: (V1+V0)C d =C d0 V0 (5) Combining equation (1), equation (3) and equation (5), we can get: After sorting, we can get: In formula (7), Δρ0 and Δρ are the density differences between the working fluid and the clean water before and after dilution, respectively. Since the working fluid reduced gravity acceleration is defined as g' = gΔρ / ρw, the relationship between the working fluid reduced gravity acceleration and the dye concentration can be obtained as g' / g0' = C d / C d0 ; The distribution of dye concentration obtained by experiment and image processing can be converted into the distribution of key parameters of ceiling jet minus gravity acceleration through this formula; (3) Detecting the distribution diagram of dye concentration to obtain the spreading speed of the working fluid; (4) Construct the scale of reduced gravity acceleration and spreading velocity between the experimental model and the full-scale tunnel prototype; The distribution of key parameters such as reduced gravity acceleration and spreading velocity obtained by the experimental system and method needs to be converted into the magnitude of reduced gravity acceleration and spreading velocity in the full-scale tunnel through similarity criteria. This conversion process complies with the following criteria; according to the Froude number formula: Where Fr is the Froude number, u is the characteristic velocity, and H is the characteristic length. The buoyancy flux is a key parameter of the buoyancy-driven flow. The buoyancy flux of the working fluid in the liquid experimental system can be calculated by the following formula: B=g'Q(9) Where B is the buoyancy flux of the working fluid per unit width of the tunnel, and Q is the flow rate of the working fluid per unit width of the tunnel. If a harmful gas leakage accident occurs in the tunnel, its buoyancy flux can be directly calculated by formula (9). If a fire accident occurs in the tunnel, the buoyancy flux of the fire source can be calculated by the following formula: Where E is the convective heat release power of the fire source, C p is the specific heat of air, ρ a and T a are the ambient air density and temperature, respectively; W is the tunnel width; the scale of the buoyancy flux in this experimental system and the full-scale tunnel is n B =B s / B f are known, the subscripts s and f represent the parameters in the experiment and prototype respectively; during the experiment, it is necessary to ensure that Fr s Number and prototype Fr f The numbers are equal, so we can construct the scale of the reduced gravity acceleration in the experiment and the prototype: Where n L represents the scale of length; Combining equation (8) and equation (11), we can get the scale of speed n V ; n V =V s / V f =n B 1 / 3 (12) (5) Use the scale to obtain the distribution of the reduced gravity acceleration and spreading velocity of the ceiling jet in the actual tunnel.

2. The experimental method for simulating smoke spread in a tunnel fire according to claim 1, characterized in that: The step 2 of obtaining the working fluid flow diagram comprises the following steps: (1) The tunnel model is placed in a water reservoir with both ends open, and the chamber inside the tunnel model is filled with clean water; (2) The dyed working fluid is injected through the liquid supply hole set at the bottom or top of the tunnel model. The working fluid forms a ceiling jet in the tunnel, and the flow diagram of the dyed working fluid at different times is obtained by taking pictures.

3. The experimental method for simulating the spread of smoke in a tunnel fire according to claim 2, characterized in that: In the step 3, the distribution diagram of the dye concentration is detected, comprising the following steps: (1) Draw a vertical line parallel to the tunnel ceiling along the distribution diagram of dye concentration, and extract all pixel points at this height; (2) Based on the distribution model of the reduced gravitational acceleration, the time-varying reduced gravitational acceleration of all pixel points on the vertical line is determined, and the corresponding change graph is obtained, thereby obtaining the transient displacement of different fluid micro-groups on the vertical line and the spreading speed of the working fluid.

4. The experimental method for simulating smoke spread in a tunnel fire according to claim 3, characterized in that: In step 3, all the oblique lines representing the transient displacement on the variation diagram are extracted by Hough transformation, and the average value of the slopes of all the oblique lines represents the spreading speed of the working fluid at the height.

5. The experimental method for simulating smoke spread in a tunnel fire according to claim 1, characterized in that: A light source is arranged outside the water reservoir to supplement the lighting of the tunnel model.

6. The experimental method for simulating smoke spread in a tunnel fire according to claim 5, characterized in that: The light source is arranged outside the rear side of the water reservoir and is a backlight plate capable of scattering light. The size of the backlight plate is equal to the size of the rear wall of the water reservoir.

7. The experimental method for simulating smoke spread in a tunnel fire according to claim 1, characterized in that: The image sampling device is arranged outside the front side of the water reservoir and is a camera.

8. The experimental method for simulating smoke spread in a tunnel fire according to claim 1, characterized in that: The liquid supply hole is arranged at the top or bottom of the tunnel model, and the liquid supply hole is connected with the liquid supply device outside the water storage tank through a pipeline.

9. The experimental method for simulating the spread of smoke in a tunnel fire according to claim 8, characterized in that: The liquid supply device is arranged outside the water reservoir, and comprises a peristaltic pump and a liquid storage tank connected to the input end of the peristaltic pump. The output end of the peristaltic pump is provided with a valve, and the valve is connected to the liquid supply hole on the tunnel model through a pipeline.

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