AU2015381974A1

AU2015381974A1 - Forest fire intensity simulator and use method thereof

Info

Publication number: AU2015381974A1
Application number: AU2015381974A
Authority: AU
Inventors: Shuifeng ZHANG; Siyu Zhang
Original assignee: Nanjing Forest Police College
Current assignee: Nanjing Forest Police College
Priority date: 2015-09-06
Filing date: 2015-09-06
Publication date: 2017-03-23
Anticipated expiration: 2035-09-06
Also published as: WO2017035830A1; AU2015381974B2; CN105723438A; CN105723438B

Abstract

Abstract The present invention discloses a forest fire intensity simulator and a use method thereof The simulator body includes a reaction chamber, a heating unit, a smoke collection unit and a temperature sensor, wherein the heating unit is arranged in the reaction chamber, temperature probes of the temperature sensor are placed in soil layers at different depths, and the smoke collection unit is arranged at the outside of the reaction chamber and is connected to the reaction chamber through a pipeline. The use method includes: inserting the bottom of the reaction chamber in a groove on the surface of undisturbed soil in an outdoor research area or indoors to carry out an experiment. Compared with the prior art, the present invention greatly reduces the cost of the forest fire simulation experiment and avoids atmospheric pollution caused by the smoke generated in the forest fire point burning experiment, and the experiment is operated in the simulator, so that the size of the fire can be controlled, the heating is uniform, and no fire escapes, so that data of heated soil can be obtained more safely and accurately, which is beneficial for the development of the soil erosion prevention and control and vegetation recovery works for the burned area after the forest fire.

Description

1

FOREST FIRE INTENSITY SIMULATOR AND USE METHOD THEREOF

Field of the Invention [0001] The present invention relates to a simulation device for study on secondary disasters of forest fires, and in particular, to a forest fire intensity simulator and a use method thereof.

Background of the Invention [0002] Around 4% of the global forest area suffers disaster loss each year, wherein forest resources destructed by forest fires accounts for nearly 1/3 of the loss of the forest resources. At present, the forest fires occur frequently around the world, about more than 220 thousand times of forest fires occur each year, and about more than 6.40 million hm2 of various forests are burnt, which accounts for about more than 0.23% of the global forest coverage. China is a country that has few forests, with the national forest coverage of only 20.36%, meanwhile, China is a country that is prone to forest fires, 16000 times of forest fires occur each year on average, and the average annual burned area is up to 9><105hm2.

[0003] Influences of fire on a forest ecological system are complex, ranging from the reduction of aboveground biomass to underground physical properties, chemical properties, microbial degradation processes and the growth of fine root systems. The fire can cause a violent change on environmental conditions within a short time, including quickly changing the physical properties and hydrological functions of forest soil, changing the C/N ratio, aggravating erosion, leaching and denitrification, resulting in the loss of soil nutrients and changing the number of microorganisms and related processes, so that the nutrient circulation and distribution of the entire forest ecological system are influenced. Whether it is beneficial or harmful to the ecological system mainly depends on the time and the intensity of the fire. In order to study the influence of burning on the forest soil, scientific experiments are necessary. 2 [0004] However, during existing scientific research on forest fire prevention, the influences of the forest fires on the soil are mainly studied in the following two ways: [0005] 1. Forest fire point burning control experiment: point burning is executed on an experimental field with a certain area (if combustibles are insufficient, combustibles need to be collected from areas with the same forest stand nearby and are spread in the point burning area), and the point burning intensity of the forest fire is estimated according to the smoked height of the forest and the amount (load) of the combustibles. After the point burning, soil and plant samples are collected, and then are analyzed in a lab. The defects of this method lie in that: the environmental pollution is relatively large, the burning intensity is hard to control, and the non-uniform soil heating intensity causes a large experimental error.

[0006] 2. The undisturbed soil in a forest land is taken out, transported to the lab and heated by a muffle furnace or other tool, the heating temperature is set according to the requirements of fire intensity, and after the heating, and the soil is cultivated in the lab by simulating the outdoor environment. The defect of the method lies in that: the original ecological system of the soil is broken to cause a relatively large experimental error.

Summary of the Invention [0007] Object of the invention: The object of the present invention is to make up the shortcomings in the prior art, and provide a forest fire intensity simulator and a use method thereof.

[0008] Technical solution: a forest fire intensity simulator includes a body, wherein the simulator body is composed of a reaction chamber, a heating unit, a smoke collection unit and a temperature sensor, the heating unit is arranged in the reaction chamber, the temperature sensor includes temperature probes, leads and a temperature display, the temperature probes are placed in soil layers at different depths, and the smoke collection unit is arranged at the outside of the reaction chamber and is connected to the reaction chamber through a pipeline. Preferably, the heating unit is a heating 3 wire arranged in the reaction chamber.

[0009] Preferably, the heating wire is composed of U-shaped heating wires which are connected in sequence.

[0010] Preferably, the heating unit is composed of combustion nozzles and an input pipeline connected with the same, the combustion nozzles are uniformly arranged at the top in the reaction chamber, one end of the input pipeline is connected with the combustion nozzles, and the other end of the input pipeline is connected with a gas cylinder or a liquid cylinder.

[0011] Preferably, a water bath spray head is arranged in the smoke collection unit for settling and adsorbing the smoke generated in the reaction chamber.

[0012] A use method of the forest fire intensity simulator includes the following use steps: [0013] 1) when being used outdoors or in a lab, digging a groove matched with the bottom edge of the reactor on the surface of undisturbed soil in an outdoor research area or indoors, the groove being about 3cm deep, inserting the bottom of the reaction chamber in the groove, and fixing the surrounding to prevent fire escape; [0014] 2) setting a heating temperature/intensity and a reaction time according to a fire level to carry out an experiment; [0015] 3) while carrying out the experiment, opening the smoke collection unit to collect the smoke; and [0016] 4) after the experiment, moving away the reaction chamber, taking out the soil samples in a layering manner according to experimental requirements, and analyzing physical properties, 4 chemical properties, biological properties and other properties.

[0017] Beneficial effects: the present invention adopts the simulator to carry out a point burning experiment, thereby greatly reducing the cost of the forest fire simulation experiment; the smoke collection unit is arranged at the outside of the reaction chamber to settle the smoke generated in the reaction, so as to avoid atmospheric pollution caused by the smoke generated in the forest fire point burning experiment, and the experiment is operated in the simulator, so that the size of the fire can be controlled; the heating wire or the combustion nozzle in the reaction chamber uniformly heats and generates no fire escape, so that experimental data of the soil can be obtained more safely and accurately, which is beneficial for the development of the soil erosion prevention and control and vegetation recovery works for the burned area after the forest fire.

Brief Description of the Drawings [0018] Fig.l is a schematic diagram of a structure of embodiment 1 of the present invention; and [0019] Fig.2 is a schematic diagram of a structure of embodiment 2 of the present invention.

Detailed Description of the Embodiments [0020] In the present invention, a reactor is made of a commercial inorganic non-metallic refractory material with refractoriness not lower than 1580°C, for example, a carbon composite refractory material, zircon refractory material and the like, and a heating wire mainly includes an aludirome electric stove wire and an iron-nickel alloy electric stove wire, which is strong in oxidation resistance, large in resistance and high in use temperature. Flammable gases are mainly adopted in gas heating, such as carbon monoxide and oxygen, hydrogen and oxygen or the like; and ethanol, gasoline and other organic liquid are mainly used in liquid heating. 5 [0021] Embodiment 1 [0022] As shown in Fig. 1, a forest fire intensity simulator includes a reaction chamber 1 with a unsealed bottom surface, a heating unit, a smoke collection unit 2 and a temperature sensor 4, wherein the heating unit is arranged in the reaction chamber 1, and the smoke collection unit 2 is arranged at the outside of the reaction chamber 1 and is connected to the reaction chamber 1 through a pipeline. In the embodiment, the heating unit is a heating wire 31 arranged at the middle of the reaction chamber 1, the heating wire is composed of U-shaped heating wires which are connected in sequence, the temperature sensor 4 is composed of temperature probes, leads and a temperature display, and a plurality of temperature probes are placed in soil layers at different depths for measuring soil temperatures.

[0023] Use method and working principle of the simulator: when the simulator in the embodiment is at work, a groove matched with the bottom edge of the reactor is dug on the surface of undisturbed soil in an outdoor research area or indoors, the groove being about 3cm deep, the bottom of the reaction chamber is inserted in the groove, the surrounding is fixed, the U-shaped heating wire switch is turned on for heating, a necessary temperature range and heating time are set according to experimental design, the temperature of the heating wire and the temperature of each soil layer are sensed by the temperature probes and are displayed on the temperature display, when the experiment is carried out, the switch of the smoke collection unit 2 needs to be turned on at the same time, and a water bath spray head 34 of the smoke collection unit 2 sprays water sprays to settle the smoke, in order to prevent the emission of harmful smoke. After the work is terminated, the reaction chamber 1 is moved away, soil samples are taken out in a layering manner according to experimental requirements, and physical properties, chemical properties, biological properties and other properties are analyzed.

[0024] Embodiment 2 [0025] As shown in Fig.2, a forest fire intensity simulator includes a body, wherein the body 6 includes a reaction chamber 1 with a unsealed bottom surface, a heating unit, a smoke collection unit 2 and a temperature sensor 4, the temperature sensor 4 is composed of temperature probes, leads and a temperature display, and a plurality of temperature probes are placed in soil layers at different depths for measuring soil temperatures. The heating unit is arranged in the reaction chamber 1, and the smoke collection unit 2 is arranged at the outside of the reaction chamber 1 and is connected to the reaction chamber 1 through a pipeline. In the embodiment, the heating unit includes combustion nozzles 32 and an input pipeline 33 connected with the same, the combustion nozzles 32 are uniformly arranged at the top in the reaction chamber, one end of the input pipeline 33 is connected with the combustion nozzles, the other end of the input pipeline is connected with a gas cylinder or a liquid cylinder, and a water bath spray head 34 is arranged in the smoke collection unit 2 for settling and adsorbing the smoke generated in the reaction chamber 1.

[0026] When in use, a groove matched with the bottom edge of the reactor is dug on the surface of undisturbed soil in an outdoor research area or indoors, the groove being about 3cm deep, the bottom of the reaction chamber is inserted in the groove, and the surrounding is fixed. Gas or liquid is input by the input pipeline, the input reaction amount of the gas or liquid is calculated and set according to the fire intensity necessary for the experiment and the calorific value of the gas or liquid in a unit volume (the standard of the fire intensity see Table 1).

Table 1 Grading standard of surface fire and crown fire intensities

Fire intensity level Low intensity Medium intensity High intensity Super-high intensity Flame height (m) Smaller than 1 1-3 3-5 Larger than 5 Fire intensity (kw/m) Smaller than 300 300-2700 2700-7000 Larger than 7000 7 [0027] The relation of the fire intensity and the calorific value of combustion can be seen from Table 1, and the input reaction rate of the gas or liquid can be calculated through two formulas.

[0028] Formula 1: (threshold of an intensity level)/ (edge length of the simulator) =(total calorific value of combustibles) [0029] Formula 2: (total calorific value of combustibles)/ (calorific value of gas or liquid in the unit volume) =(gas/liquid fuel volume) [0030] Ignition is carried out by the combustion nozzles to point burn the undisturbed soil at the bottom of the reactor, the flame temperature and the temperature of each soil layer are sensed by the temperature probes and are displayed on the temperature display. When the experiment is carried out, the switch of the smoke collection unit 2 needs to be turned on at the same time, and the water bath spray heads 34 of the smoke collection unit 2 sprays water sprays to settle the smoke, in order to prevent the emission of harmful smoke, after the work is terminated, the reaction chamber 1 is moved away, soil samples are taken out in a layering manner according to experimental requirements, and physical properties, chemical properties, biological properties and other properties are analyzed.

[0031] Compared with the prior art, the embodiment greatly reduces the cost and is safer; the heating wire or the combustion nozzles are used as the heating unit, so that the heating is uniform, which is conducive to carrying out the experiment more accurately and better analyzing the experimental result, and moreover, the design of the present invention greatly reduces the possibility of environmental pollution, thereby being beneficial for environmental protection.

Claims

Claims

1. A forest fire intensity simulator, comprising a body, wherein the simulator body comprises a reaction chamber (1), a heating unit, a smoke collection unit (2) and a temperature sensor (4), the heating unit is arranged in the reaction chamber (1), the temperature sensor (4) comprises temperature probes, leads and a temperature display, the temperature probes are placed in soil layers at different depths, and the smoke collection unit (2) is arranged at the outside of the reaction chamber (1) and is connected to the reaction chamber (1) through a pipeline.
2. The forest fire intensity simulator of claim 1, wherein the heating unit is a heating wire (31) arranged in the reaction chamber (1).
3. The forest fire intensity simulator of claim 2, wherein the heating wire (31) is composed of U-shaped heating wires which are connected in sequence.
4. The forest fire intensity simulator of claim 1, wherein the heating unit comprises combustion nozzles (32) and an input pipeline (33) connected with the combustion nozzles (32), the combustion nozzles (32) are uniformly arranged at the top in the reaction chamber (1), and the input pipeline (33) is connected with the combustion nozzles (32) at one end and connected with a gas cylinder or a liquid cylinder at the other end.
5. The forest fire intensity simulator of claim 2 or 4, wherein a water bath spray head (34) is arranged in the smoke collection unit (2) for settling and adsorbing the smoke generated in the reaction chamber (1).
6. A use method of the forest fire intensity simulator of claim 1, comprising the following use steps: 1) when being used outdoors or in a lab, digging a groove matched with the bottom edge of the reactor on the surface of undisturbed soil in an outdoor research area or indoors, the groove being about 3cm deep, inserting the bottom of the reaction chamber in the groove, and fixing the surrounding to prevent fire escape; 2) setting a heating temperature/fuel volume and reaction time according to a fire level to carry out an experiment; 3) while carrying out the experiment, opening the smoke collection unit to collect the smoke; and 4) after the experiment, moving away the reaction chamber, taking out the soil samples in a layering manner according to experimental requirements, and analyzing physical properties, chemical properties, biological properties and other properties.