Forest fire wind tunnel simulation experiment device and method

Abstract

The invention belongs to the field of fire simulation experiments, and provides a forest fire wind tunnel simulation experiment device and method, and the method comprises the steps: carrying out the combustion experiment of a self-designed combustion platform which fits the features of terrain and cover vegetation, so as to obtain the fire behavior duration, spreading trend, damage degree and the like of forest fire, and carrying out the data integration; according to the invention, wind tunnel simulation is utilized, influence factors of various forest fires are comprehensively considered for a simulation experiment, and the simulation experiment is closer to real forest fires through a series of methods; the fire behavior characteristics, the flame spreading rule, the fire influence range and the forest ecological vegetation damage condition after the forest fire is influenced by various factors are explored, and a powerful basis is provided for forest fire prevention and control.

Description

Technical Field

[0001] The present invention belongs to the field of fire simulation experiments, and particularly relates to a forest fire wind tunnel simulation experiment device and method. Background Art

[0004] Currently, research on the fire characteristics and flame spread law of forest fires includes: Patent No. CN202011564850.6 discloses an experimental method for simulating forest fire behavior characteristics and spread and diffusion mechanism using a wind tunnel, but the geomorphic feature data only considers some slope values, and the selected combustibles are relatively single. Patent No. CN202221435772.4 discloses a small wind tunnel experimental platform similar to a combustion chamber to simulate forest fires. The simulation of the airflow state of forest fires mainly studies by controlling the gas parameters blown into the combustion chamber, such as flow rate, temperature, humidity, etc., to simulate forest fires under different environmental conditions. The used combustion chamber is quite different from the actual combustion situation, and the reproduction degree of the actual behavior of forest fires is poor. Patent No. CN201711191426.X conducts combustion characteristic drills, mainly simulating the smoke flow and diffusion, and does not mention the characteristics of forests. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a forest fire wind tunnel simulation experiment device and method to solve the problems in the prior art. The technical solution adopted by the present invention is as follows:

[0006] A forest fire wind tunnel simulation experiment device is provided in a wind tunnel, and it includes a frame 1, a grid plate 3, columns 8, a filler 9, and a flame-retardant fabric;

[0007] A plurality of mesh holes are distributed on the grid plate 3, and the plurality of mesh holes together form a grid-like structure. A liftable column 8 is arranged in each mesh hole, and the heights of the plurality of columns 8 are different to simulate the terrain environment;

[0008] The filler 9 is filled between the plurality of columns 8. The flame-retardant fabric includes a root part, a flat part, and a branch and leaf part; the root part is inserted into the filler 9, the flat part is laid on the filler 9, and the branch and leaf part is erected on the flat part.

[0009] Further, it further includes a frame 1. The frame 1 is provided with a trough with an upward opening. The filler 9 is located in the trough, and the grid plate 3 is fixedly connected in the trough.

[0010] Further, the plurality of columns 8 are distributed in a rectangular array of multiple rows and multiple columns, and the bottoms of the columns 8 in each row are connected by a chain 7;

[0011] A plurality of rollers 6 are arranged below the grid plate 3. The axis of the roller 6 is perpendicular to the length direction of the chain 7. The roller 6 is located below the chain 7 and supports the chain 7, so that the chain 7 is bent, and the heights of the plurality of columns 8 are different.

[0012] Furthermore, the roller 6 is rotatably arranged on a bracket. The bottom of the bracket is fixedly connected to a lifting device 5, and the lifting device 5 is installed on a transverse movement device 4.

[0013] A method for simulating forest fire in a wind tunnel includes the following steps:

[0014] Step 1: Debug the wind field, temperature field, and velocity field in the wind tunnel according to the experimental requirements until the experimental requirements are met;

[0015] Step 2: Adjust the heights of a plurality of columns 8 according to the experimental requirements to simulate terrains such as mountains and hills, and fillings 9 are laid between the columns 8;

[0016] Step 3: Lay the flat part of the flame-retardant woven fabric on the filling 9 according to the experimental requirements, insert the root part into the filling 9, and connect the branch and leaf part above the root part;

[0017] Step 4: Conduct an ignition experiment and ignite the flame-retardant woven fabric in the experiment.

[0018] Step 5: Continuously use a high-definition camera to shoot the combustion and spread process of the flame to record the characteristics of the combustion fire, the law of flame spread, the scope of the fire impact, and the damage to the forest ecological vegetation after the disaster;

[0019] Step 6: Until the combustion ends and there is no obvious flame.

[0020] Furthermore, the flame-retardant woven fabric is prepared by soaking the woven material with a flame-retardant solution:

[0021] Put the woven material into the flame-retardant solution and soak it, while performing ultrasonic treatment for 15 minutes. Finally, divide the treated woven material into two parts and perform drying treatment respectively, so that the water content of the woven material reaches 50%-60% and 75%-85%, which are respectively used for weaving the branches and trunks of arbors, shrubs and herbs, and obtain a flame-retardant woven fabric with flame-retardant ability.

[0022] Furthermore, the flame-retardant solution is prepared by the following method: Weigh equal amounts of tris-isocyanuric acid ester and ammonium polyphosphate powder and put them into ionized water at a temperature of 40°C. Place them on a magnetic stirrer and stir for 40 minutes. Then put them into an ultrasonic cleaner and ultrasonicate for 10 minutes. Wait until the solvent is dissolved and mixed evenly to obtain the flame-retardant solution.

[0023] Furthermore, the flame retardant solution is prepared by the following method: Weigh 106 g of sodium hypophosphite monohydrate and dissolve it in 750 ml of water. Transfer the solution to a pressure-resistant reaction kettle equipped with an ultraviolet lamp at room temperature and introduce ethylene gas. Keep the pressure in the reaction kettle at 5 atm. Slowly and evenly drop 1.45 g of acetone within 6 hours. After the photoinitiator is completely dropped, react for another 1 h to obtain the flame retardant solution.

[0024] The present invention has the following beneficial effects:

[0025] The present invention designs an experimental scheme for simulating forest fires using a large wind tunnel. A combustion platform is built in the large wind tunnel environment to 3D simulate topographic features such as mountains and hills, as well as forest vegetation coverage features such as arbors, shrubs, humus, and herbs, reproducing the complex terrain of the forest. Compared with the previous method of simulating terrain conditions by the heights of multiple cylinders in research, the present invention uses flame-retardant treated woven materials to achieve 3D simulation of forest vegetation, enhancing the restoration of the actual situation of forest fires.

[0026] The present invention uses a large environmental wind tunnel to simulate the topographic features and forest-like growth appearance of the combustion platform, truly reflecting the impact of geological conditions, vegetation coverage, and atmospheric wind environment on forest fires during a fire, enhancing the restoration of the actual situation of forest fires. The degree of conformity between the obtained fire characteristics data such as the characteristics of the fire, the law of flame spread, the scope of fire impact, and the damage to forest ecological vegetation after the fire and the actual situation is greatly increased, providing a strong basis for the prevention and control of real forest fires. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the flame-retardant fabric;

[0028] Figure 2 It is a schematic diagram of the simulation experimental device;

[0029] Figure 3 It is a top view schematic diagram of the grid plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, in combination with the Figures 1 - 3 in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. If not specifically specified, the technical means used in the embodiments are conventional means well-known to those skilled in the art.

[0031] A forest fire wind tunnel simulation experimental device, which is arranged in a wind tunnel and includes a frame 1, a grid plate 3, columns 8, fillers 9, and a flame-retardant fabric;

[0032] A plurality of mesh holes are distributed on the mesh plate 3, and the plurality of mesh holes together form a grid-like structure. A liftable column 8 is arranged in each mesh hole, and the heights of the plurality of columns 8 are different to simulate the terrain environment;

[0033] The filler 9 is filled between the plurality of columns 8. The flame-retardant fabric includes a root part, a flat-laying part, and a branch-and-leaf part; the root part is inserted into the filler 9, the flat-laying part is laid on the filler 9, and the branch-and-leaf part is erected on the flat-laying part.

[0034] The filler 9 can be a base layer obtained by mixing gravel, plastic clay, diatomite, ceramsite, etc. in a certain proportion. The flame-retardant fabric is woven from a variety of fiber materials such as flame-retardant treated flax and cotton, realizing the 3D simulation design of trees, shrubs, humus, herbs, etc., and reproducing the actual combustion process of water-containing vegetation through the use of flame-retardant liquid. Specifically in implementation, the flame-retardant fabric is woven and wound into structures similar to trees, shrubs, humus, herbs, etc., and a root part is woven at its bottom, thereby simulating the plant structure. The root part is directly inserted into the filler 9, and the branch-and-leaf part is at a certain height from the flat-laying part.

[0035] In addition, a fire-spraying device, such as a flamethrower, a flame gun, etc., can be arranged on the mesh plate 3. The fire-spraying device is arranged at the front end of the mesh plate 3, and the wind direction in the wind tunnel is from front to back. After the fire-spraying device ignites for a period of time, when the filler 9 and the flame-retardant fabric on the mesh plate 3 form a flame, then start the wind tunnel to conduct the experiment, which can simulate the fire process.

[0036] The present invention uses wind tunnel simulation to comprehensively consider various influencing factors of forest fires for simulation experiments. Through a series of methods, the simulation experiments are made closer to real forest fires, realizing the exploration of the fire characteristics, flame spread law, fire influence range, and the damage situation of forest ecological vegetation after the fire when forest fires are affected by various factors, providing a strong basis for forest fire prevention and control.

[0037] Furthermore, it further includes a frame body 1. The frame body 1 is provided with a groove body with an upward opening, the filler 9 is located in the groove body, and the mesh plate 3 is fixedly connected in the groove body.

[0038] Furthermore, the plurality of columns 8 are distributed in a rectangular array of multiple rows and multiple columns, and the bottoms of the columns 8 in each row are connected by a chain 7;

[0039] A plurality of rollers 6 are arranged below the mesh plate 3. The axis of the roller 6 is perpendicular to the length direction of the chain 7. The roller 6 is located below the chain 7 and supports the chain 7, so that the chain 7 is bent, making the heights of the plurality of columns 8 different.

[0040] Further, the roller shaft 6 is rotatably arranged on the bracket, the bottom of the bracket is fixedly connected with a lifting device 5, and the lifting device 5 is installed on the transverse movement device 4.

[0041] The lifting device 5 is a prior art, such as a cylinder, a hydraulic cylinder, etc. By moving the roller shaft 6 back and forth, the heights of the cylinders 8 at different positions can be uniformly changed, so as to form cylinders 8 with different heights and levels, so as to simulate different terrain environments with undulating heights. And by adjusting the height of the roller shaft 6 through the lifting device 5, the maximum height of the cylinder 8 and the height difference between different cylinders 8 can be adjusted. The function of the chain 7 is to support a plurality of cylinders 8, and the part of the chain 7 not supported by the cylinders 8 forms a naturally drooping posture.

[0042] A forest fire wind tunnel simulation experiment method includes the following steps:

[0043] Step 1: Debug the wind field, temperature field, and velocity field in the wind tunnel according to the experimental requirements until the experimental requirements are met.

[0044] Step 2: Adjust the heights of a plurality of cylinders 8 according to the experimental requirements to simulate terrains such as mountains and hills. Fillers 9 are laid between the cylinders 8. The fillers 9 are a mixture obtained from quartzite gravel, plastic clay, diatomite, ceramsite, etc. according to a certain ratio.

[0045] Step 3: Lay a flat part of a flame-retardant woven material on the filler 9 according to the experimental requirements. Insert the root part into the filler 9. The upper part of the root part is connected to the branch and leaf part. The branch and leaf part extends upward from the flat part by a certain height, and a layer of soil just covering is covered on the flat part.

[0046] Step 4: Conduct an ignition experiment and ignite the flame-retardant woven material in the experiment.

[0047] Step 5: Continuously shoot the combustion and spread process of the flame with a high-definition camera to record the characteristics of the combustion fire, the law of flame spread, the scope of fire impact, and the damage to forest ecological vegetation after the disaster.

[0048] Step 6: Until the combustion ends, there is no obvious flame and no smoke, then turn off the fan and other adjustment devices, and tidy up the wind tunnel experiment environment to restore it to its original state.

[0049] Further, the flame-retardant woven fabric is prepared by soaking the woven material with a flame-retardant solution:

[0050] Put the woven material into the flame-retardant solution for soaking, and at the same time perform ultrasonic treatment for 15 minutes. Finally, divide the treated woven material into two parts and perform drying treatment respectively, so that the water content of the woven material reaches 50%-60% and 75%-85%, which are respectively used for weaving the branches and trunks of arbors, shrubs and herbs, to obtain a flame-retardant woven fabric with flame-retardant ability.

[0051] The woven material can be linen, cotton strips, straw fibers or a mixture thereof. It is kneaded and woven, and the weaving method draws on various Chinese knot braiding methods. A net with a grid area of about 1 dm 2 can be woven with the above-mentioned braided rope. At the same time, at the intersections of the grids, randomly weave upwards to obtain the shape of a tree, which includes tree trunks and branches of different diameters, and also weave relatively low shrubs and grass structures. At the places where the shapes of the trees and shrubs are woven, weave the downward root parts to simulate the rhizomes of forest vegetation growing underground. The woven forest vegetation simulation component is laid on the combustion platform and covered with a layer of soil that just covers the woven net.

[0052] Furthermore, the flame retardant solution is prepared by two methods:

[0053] (1) Weigh equal amounts of tris-isocyanuric acid ester and ammonium polyphosphate powder and put them into ionic water at a temperature of 40 °C. Place them on a magnetic stirrer and stir for 40 min. Then put them into an ultrasonic cleaner and ultrasonicate for 10 min. Wait until the solvent is dissolved and mixed evenly to obtain the flame retardant solution.

[0054] (2) Weigh 106 g of sodium hypophosphite monohydrate and dissolve it in 750 ml of water. Transfer the solution to a pressure-resistant reaction kettle with an ultraviolet lamp at room temperature and introduce ethylene gas. Keep the pressure in the reaction kettle at 5 atm. Slowly and evenly drop 1.45 g of acetone within 6 hours. After the photoinitiator is completely dropped, react for 1 h to obtain the flame retardant solution.

[0055] For the wind tunnel simulation technology of forest fires, it mainly focuses on the in-chamber simulation experiments of the characteristics of biomass combustion, fire behavior, smoke, and terrain. The shape of its combustion platform is simple, and most of them cannot be carried out in a large environmental wind tunnel, with a large gap from the combustion situation of the large-space spread of actual forest fires. The simulation of forest terrain only has the design of slope, and the terrain structure simulation parameters are single. Laying biomass on the platform for the combustion experiment of forest fires, its simulation method is rough. The present invention focuses on the application of a large environmental wind tunnel, simulates the growth appearance of a forest on the combustion platform, truly reflects the influence of geological conditions, vegetation cover, and atmospheric wind environment on forest fires during a fire, enhances the restoration of the actual situation of forest fires, and greatly increases the degree of conformity between the obtained fire characteristic data and the actual situation.

[0056] The above-described embodiments are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations, variations, modifications, and substitutions made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. Forest fire wind tunnel simulation experimental device, characterized in that: The experimental device is arranged in a wind tunnel and comprises a frame (1), a grid plate (3), a column (8), a filler (9) and a flame-retardant braid; The grid plate (3) is provided with a plurality of mesh holes, which together form a grid mesh structure, and a liftable column (8) is arranged in each mesh hole, and the plurality of columns (8) are arranged at different heights to simulate a terrain environment; The filler (9) is filled between the plurality of columns (8), and the flame-retardant woven fabric comprises a root part, a flat part and a branch part; the root part is inserted into the filler (9), the flat part is laid on the filler (9), and the branch part is erected on the flat part.

2. The forest fire wind tunnel simulation experimental device according to claim 1, characterized in that: It also comprises a frame (1), the frame (1) being provided with a slot with an opening facing upwards, the filler (9) being located in the slot, and the grid plate (3) being fixedly connected in the slot.

3. The forest fire wind tunnel simulation experimental device according to claim 1, characterized in that: The plurality of columns (8) are distributed in a rectangular array of multiple rows and columns, wherein the bottoms of the columns (8) in each row are connected by a chain (7); A plurality of rollers (6) are arranged below the grid plate (3), the axes of the rollers (6) being perpendicular to the length direction of the chain (7), and the rollers (6) being located below the chain (7) and supporting the chain (7), so that the chain (7) is distributed in a curved manner, so that the heights of the plurality of columns (8) are different.

4. The forest fire wind tunnel simulation experimental device according to claim 3 is characterized in that: The roller shaft (6) is rotatably arranged on a bracket, the bottom of the bracket is fixedly connected to a lifting device (5), and the lifting device (5) is installed on the transverse movement device (4).

5. A forest fire wind tunnel simulation test method, applied to the forest fire wind tunnel simulation test device according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Debug the wind field, temperature field, and velocity field in the wind tunnel according to the experimental requirements until they meet the experimental requirements; Step 2: adjusting the heights of the multiple columns (8) according to the experimental requirements to simulate terrain such as mountains and hills, and laying fillers (9) between the columns (8); Step 3: Lay the flat part of the flame-retardant woven fabric on the filler (9) according to the experimental requirements, insert the root part into the filler (9), and connect the branches and leaves part above the root part; Step 4: Conduct an ignition experiment to ignite the flame-retardant fabric in the experiment. Step 5: Use a high-definition camera to continuously shoot the burning and spreading process of the flames to record the characteristics of the burning fire, the law of flame spread, the scope of fire impact, and the damage to the forest ecological vegetation after the disaster; Step 6: Continue until the combustion is complete and there is no obvious flame.

6. The forest fire wind tunnel simulation experimental method according to claim 5, characterized in that: The flame retardant woven fabric is prepared by soaking the woven material in a flame retardant solution: The woven material is immersed in a flame retardant solution and ultrasonically treated for 15 minutes. Finally, the treated woven material is divided into two parts and dried separately so that the moisture content of the woven material reaches 50%-60% and 75%-85%, which are used for weaving trees, shrub branches and herbs respectively to obtain flame retardant woven fabrics with flame retardant ability.

7. The forest fire wind tunnel simulation experimental method according to claim 6, characterized in that: The flame retardant solution was prepared by the following method: equal amounts of triisocyanurate and ammonium polyphosphate powder were weighed and put into deionized water at 40°C, stirred on a magnetic stirrer for 40 minutes, and then put into an ultrasonic cleaner for 10 minutes, and the solvent was dissolved and mixed evenly to obtain a flame retardant solution.

8. The forest fire wind tunnel simulation experimental method according to claim 6, characterized in that: The flame retardant solution was prepared by the following method: 106 g of sodium hypophosphite monohydrate was weighed and dissolved in 750 ml of water. The solution was transferred to a pressure-resistant reactor equipped with an ultraviolet lamp at room temperature and ethylene gas was introduced. The pressure in the reactor was maintained at 5 atm. 1.45 g of acetone was evenly and slowly added within 6 hours. After the photoinitiator was completely added, the reaction was carried out for 1 hour to obtain a flame retardant solution.

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