Method and system for detecting thermal radiation shielding effect of plant leaves in forest fire

Abstract

The invention provides a method and system for detecting the thermal radiation effect of plant leaves in a forest fire, and is applied to the technical field of detection of the thermal radiation effect of the plant leaves and screening of fireproof tree species. The method comprises the steps that a heating device is used for simulating fire source heat radiation in a forest fire scene, a fan is used for simulating convection in the forest fire scene, and thermal attack is conducted on detected blades in a heat radiation and heat convection coupling mode; according to the original leaf area of the detected leaf and the leaf vertical projection area after the thermodynamic attack, determining the crimpness of the detected leaf; according to the crimpness, determining the thermal radiation shielding capability of the detected blade at the preset temperature; according to the leaf quality of the detected leaf after the thermal attack, determining the thermal stability of the detected leaf at the preset temperature; the heating device sets component turns to increase the preset temperature, detects the thermal radiation shielding capability and thermal stability of the blade in a continuously enhanced thermal attack scene, and quantifies the shielding thermal radiation effect of the detected blade.

Description

Technical Field

[0001] The present disclosure relates to the technical field of leaf fire resistance characteristics and effectiveness detection, specifically to the evaluation technology of plant leaf fire resistance and the impact on energy transfer during forest fires, especially to the application of the fire-retardant mechanism of biological fire-prevention forest belts and the screening and identification of key performance of fire-resistant tree species, and also to the quantitative assessment of the efficiency of plant leaves in suppressing and blocking the transmission of forest fire radiation energy during forest fires, and more broadly to a method and system for detecting the effect of plant leaves blocking thermal radiation during forest fires. Background Art

[0002] When evaluating the fire protection properties and effectiveness of plant leaves, the focus is usually on analyzing several key characteristics of plant leaves, such as differences in the chemical composition of plant leaves, flammability, and ignition characteristics after contact with flames.

[0003] Naturally grown plant leaves do not differ significantly in many physical and chemical properties. For example, some plant leaves have similar content of cellulose, lignin, and oil, along with nearly identical elemental compositions and ignition characteristics. Existing key property analysis methods fail to consider the energy transfer patterns in actual forest fire scenarios and the shielding properties of specific leaves, making them unable to accurately assess the fire-resistant properties and effectiveness of plant leaves. Summary of the Invention

[0004] In view of the above problems, the present disclosure provides a method and system for detecting the effect of plant leaves blocking heat radiation during forest fires.

[0005] According to a first aspect of the present disclosure, a method for detecting the effect of plant leaves blocking thermal radiation in a forest fire is provided, comprising: using a heating device to simulate fire source thermal radiation in a forest fire scenario in a detection environment, using a fan to simulate convection in the forest fire scenario, and subjecting the inspected leaves to a thermal attack in the form of coupled thermal radiation and thermal convection, wherein the heating device is set to increase a preset temperature in cycles to create a continuously intensified thermal attack scenario; determining the curl of the inspected leaves based on the original leaf area of ​​the inspected leaves and the vertical projection area of ​​the leaves after the thermal attack; determining the thermal radiation blocking ability of the inspected leaves at the preset temperature based on the curl; determining the thermal stability of the inspected leaves at the preset temperature based on the leaf mass of the inspected leaves after the thermal attack; and increasing the preset temperature according to a predetermined step size to determine the thermal radiation blocking ability and thermal stability of the inspected leaves at different preset temperatures, so as to determine the thermal radiation blocking effect of the inspected leaves based on the thermal radiation blocking ability and thermal stability of the inspected leaves at the different preset temperatures.

[0006] According to an embodiment of the present disclosure, the curl degree is determined by the following formula (1):

[0007] (1)

[0008] in, is the curling degree of the above-mentioned blade in the jth round, is the original leaf area of ​​the above-mentioned leaf under examination, is the vertical projection area of ​​the inspected blade in the jth wheel, j ≥ 1 and j is a positive integer.

[0009] According to an embodiment of the present disclosure, determining the thermal stability of the inspected blade at the preset temperature based on the leaf mass of the inspected blade after the thermal attack includes: determining the weight loss rate of the inspected blade based on the original leaf mass, the original water content, and the leaf mass after the thermal attack of the inspected blade, wherein the weight loss rate is determined by the following formula (2):

[0010] (2)

[0011] in, is the weight loss rate of the inspected blade in the jth round, is the original water content of the above-mentioned leaves, is the original leaf mass of the above-mentioned inspected leaf, is the blade mass of the inspected blade in the jth round; and according to the weight loss rate, the thermal stability of the inspected blade at the preset temperature is determined.

[0012] According to an embodiment of the present disclosure, the method for detecting the effect of plant leaves blocking heat radiation in forest fires further includes: when the preset temperature is in a first temperature range, determining the water retention of the inspected leaves at the preset temperature based on the weight loss rate; when the preset temperature is in a second temperature range, determining the anti-evaporation ability of the inspected leaves at the preset temperature based on the weight loss rate; and when the above-mentioned preset temperature is in a third temperature range, determining the thermal stability of the main material of the above-mentioned inspected leaves after the moisture is basically eliminated after multiple rounds of thermal attacks at the above-mentioned preset temperature based on the above-mentioned weight loss rate and the above-mentioned original water content. According to an embodiment of the present disclosure, the method for detecting the effect of plant leaves blocking heat radiation in forest fires further includes: adjusting the speed of the fan to adjust the intensity of heat convection.

[0013] According to a second aspect of the present disclosure, a system for detecting the effect of plant leaves blocking thermal radiation in a forest fire is provided. The system comprises: a housing for providing a detection environment; a heating device disposed on an inner wall of the housing for simulating the heat radiation from a fire source in the forest fire scenario; the heating device is set to increase a preset temperature in cycles to create a continuously intensifying thermal attack scenario; the heating device is adjusted to a preset temperature; a fan disposed on a top of the housing for simulating convection in the forest fire scenario; the heating device and the fan perform a thermal attack on the inspected leaves in the form of coupled thermal radiation and thermal convection; a processing device for determining the thermal radiation blocking capability of the inspected leaves at the preset temperature based on the vertical projection area of ​​the leaves after the thermal attack; determining the thermal stability of the inspected leaves at the preset temperature based on the leaf mass of the inspected leaves after the thermal attack; and adjusting the preset temperature and determining the thermal radiation blocking capability and thermal stability of the inspected leaves at different preset temperatures, so as to determine the thermal radiation blocking effect of the inspected leaves based on the thermal radiation blocking capability and thermal stability of the inspected leaves at the different preset temperatures.

[0014] According to an embodiment of the present disclosure, a guide rail is provided inside the box, and the system further includes: a fixing device for fixing the inspected blade; a sample transporting device, which is slidably provided on the guide rail, for clamping the fixing device and sliding along the guide rail to transport the fixing device from the outside of the box to the inside of the box, or to transport the fixing device from the inside of the box to the outside of the box.

[0015] According to an embodiment of the present disclosure, the fixing device includes: a fixing frame; and a clamp flexibly arranged on the fixing frame for fixing the inspected blade.

[0016] According to an embodiment of the present disclosure, the sample delivery device includes: a crossbeam for clamping the fixing device; and a baffle for reducing heat leakage in the box during the transportation of the fixing device.

[0017] According to an embodiment of the present disclosure, the system further includes a collection device, which includes: a leaf area analyzer for collecting the vertical projection area of ​​the inspected leaf; and a balance for collecting the leaf mass of the inspected leaf.

[0018] The method and system provided in this embodiment for detecting the effect of plant leaves blocking thermal radiation during forest fires have the following advantages:

[0019] (1) By constructing a heating mode that combines thermal radiation and thermal convection and using an increasingly advanced step-by-step heating method, the thermal attack scenario at an actual forest fire scene is simulated, which is highly consistent with the typical characteristics of the leaf surface heating at an actual fire scene.

[0020] (2) With the help of a leaf area analyzer and a high-precision balance, we can accurately extract the vertical projection area data of the leaves after the step-by-step thermal attack and track the changes in the leaf weight in real time. By recording this data, we can effectively obtain the cumulative effect of the leaves on the coupling of thermal radiation and thermal convection.

[0021] (3) During the experiment, the heating samples were selected from leaves in the same area and at the same time, and the same installation and heating methods were used. This ensured that the curling and weight loss of the leaves during the heating process were highly consistent and repeatable.

[0022] (4) Under continuously intensified heating conditions, the weight loss rate information obtained under different thermal levels and temperature ranges can be obtained, which can be used to calibrate the water retention at room temperature, the water evaporation characteristics at around 100°C, and the thermal stability at higher temperatures. Three different material properties can be extracted and calibrated simultaneously, with outstanding advantages in both detection efficiency and the range of properties covered by calibration.

[0023] (5) The detection method of this embodiment can evaluate the heat radiation resistance and fire resistance of any type of leaves. Whether it is a leathery leaf or a papery leaf, its ability to resist heat radiation and heat convection can be evaluated by observing its curling degree and weight loss after being heated.

[0024] (6) Extract the curling degree and weight loss rate of the parallel comparative experiments. These data can be directly used to compare the water retention capacity and radiation blocking capacity of different leaf types under thermal attack, providing important technical support for the selection of ideal tree species for biological fire prevention forests in specific forest areas.

[0025] (7) Compared with the traditional plant fire resistance test which requires the analysis of ash composition and other information, the extraction of leaf area and mass parameters in the detection method of this embodiment is simple, and the experimental phenomena are significant, which effectively improves the reliability of the test results and correspondingly expands the actual application scenarios.

[0026] (8) The entire detection method of this embodiment does not involve combustion. Compared with traditional combustion experiments, there is almost no pollutant emission, completely eliminating the potential harm to the environment caused by the testing process.

[0027] (9) The detection method and corresponding system of this embodiment are highly operable, easy to implement, and convenient for technical personnel to master and use.

[0028] (10) The detection method of this embodiment has a low implementation cost. For example, the preparation and testing costs of the samples such as the leaves to be tested are both at a low level. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0030] Figure 1 A flowchart of a method for detecting the effect of plant leaves blocking heat radiation in a forest fire according to an embodiment of the present disclosure is schematically shown;

[0031] Figure 2 A schematic diagram schematically illustrates a preset temperature according to an embodiment of the present disclosure;

[0032] Figure 3 The following schematically illustrates the technical principle and detection process diagram according to an embodiment of the present disclosure;

[0033] Figure 4 The following schematically shows a system for detecting the effect of plant leaves blocking heat radiation in forest fires according to a specific embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0035] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0036] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0037] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0038] Forest fires are characterized by the continuous expansion of energy waves generated by the burning of forest fuels. To prevent and control forest fires, scholars and experts in many forest-affected countries around the world have engaged in long and arduous research and efforts. Currently, a considerable amount of scientific knowledge has been developed regarding the mechanisms of fire spread and the behavior of plants during forest fires, including the main drivers of fire spread and the patterns of energy transfer. Research has shown that forest fires primarily spread through the diffusion of energy from thermal radiation from the flame zone to unburned areas. Simultaneously, convection contributes intermittently to the heating of unburned areas. Due to the influence of ambient airflow, the effects of thermal radiation and convection are largely discontinuous; only as the flames approach, the thermal attack on the unburned areas tends to intensify.

[0039] Forest fires are primarily categorized as surface fires and crown fires. Crown fires, marked by the ignition of the tree crown, release significant energy and are typically seen during large forest fires. Due to the diversity of forest vegetation, foliage varies significantly, ranging from coniferous to broadleaf, and from fresh to old. Coniferous crowns are generally susceptible to ignition, while broadleaf crowns are more difficult. This is because their water-retaining properties absorb and shield the transmission of thermal radiation energy during a fire. A well-known example is the widespread development of biological fire-prevention belts in my country's forests, a technique that utilizes broadleaf trees to block forest fires. These unique forest stands, formed through dense planting and years of maintenance, virtually eliminate surface fuel cover under the forest floor. Furthermore, their distance from nearby more flammable stands means that the external thermal attack they receive primarily comes from flame radiation from the already burned areas and occasional inbound heat waves. Under attack, leaves, with their high water-retention capacity, often continuously mitigate thermal damage by relying on their ability to float and form layers of shielding, ultimately blocking the fire's path. Past fires have shown that rows of firebreaks near the source of a fire experience varying degrees of burns and even localized combustion, but the fire ultimately stops deep within the belt. Long-term practice has confirmed that biological firebreaks can at least block moderate crown fires. However, when large amounts of flying fire are present, biological firebreaks are unable to fully absorb or prevent the spread of the fire due to factors such as its height and density.

[0040] Studies on the behavior of broadleaf leaves during fires have shown that they form a contact surface when receiving ambient thermal radiation, concentrating external thermal attack on naturally formed, loose surfaces. This phenomenon, defined as the surface effect, applies to all broadleaf trees. In a specific heat environment, how and how effectively leaves receive thermal radiation largely determines whether they will ignite and become a relay for the spread of fire. Frontline firefighters and engineering technicians often observe that the presence of broadleaf trees along a fire's path often acts as a barrier to the spread of the fire, a phenomenon closely related to the characteristics of their crowns and changes in the distribution of surface fuels. Because needles cannot form a receiving surface, external heat flux radiation produces a highly efficient field effect, which, combined with the influence of other properties, easily leads to the formation of crown fires.

[0041] Over the years, numerous fire prevention experts and engineers have devoted significant time and effort to conducting extensive and in-depth experimental research on fire-resistant tree species to further optimize the tree species configuration and enhance their fire prevention effectiveness. During this research, the testing and evaluation methods developed and employed primarily focused on analyzing key characteristics of plant leaves, including differences in chemical composition, flammability, and ignition characteristics upon flame exposure. In practice, researchers conducted tests based on current industry standards, such as the "LYJ127-2012 Forest Fire Prevention Engineering Technical Standard" and the "LY / T 5007 Forest Fire Barrier System Construction Standard." Furthermore, researchers also conducted ignition tests on leaf samples from various tree species, drawing on vertical burning standards such as GB / T 5455-2014, ISO 15025, ASTM D6413-15, and UL 94-V. By recording various data such as the time it takes for a single leaf to burst into flame, the burning speed, the flame height, and the presence of fly-fire, a comprehensive assessment of the fire-resistant properties and effectiveness of a specific tree species can be made. Some researchers have also conducted comparative tests using cone calorimeters to observe the ignition time and heat release rate of specific leaves, thereby calibrating differences in flammability between leaves. However, in actual screening, it has been found that naturally grown plant leaves do not differ significantly in many physical and chemical properties. For example, chemical composition analysis shows that some plant leaves contain similar levels of cellulose, lignin, and oil, with nearly identical elemental compositions and similar ignition characteristics. These previously obtained specious conclusions are extremely detrimental to strengthening the technical foundation of biological fire prevention standards and even ecological fire prevention. Existing testing methods and standards for material flammability and combustion characteristics were primarily developed for fire protection within factories, mines, commercial buildings, and residential buildings, and cannot provide reliable technical guidance for ecological fire prevention. As we all know, the proper selection of tree species with good fire resistance will help guide the subsequent planning and implementation of fire prevention forest belts, so that the forest belts can play a more effective barrier role when facing the threat of fire and reduce the damage caused by fire to resources and the environment.

[0042] The latest understanding of forest fire spread and the laws of energy transfer show that only by understanding the actual energy transfer mode can the function of biological fire prevention belts, especially their effectiveness in blocking flame radiation, be essentially explained. In fact, as early as around 1995, the famous forest fire expert, the late Professor Zheng Huanneng of Northeast Forestry University, made it clear that the fire-blocking effectiveness of biological fire prevention belts lies in their forest stand structure and the individual trees themselves that are planted and grown in three dimensions. However, this is only a statement based on intuitive understanding on the scene, and does not start from the basic principles of forest fire energy transfer. Based on the actual needs of the project, the embodiments of the present disclosure propose a new detection method to highlight the actual efficacy of fire-resistant tree species at the fire scene, laying a technical foundation for the functional confirmation and precise screening of fire-resistant tree species, and consolidating the actual role of fire prevention belts. The relevant detection technologies and systems also create conditions for revealing the laws of energy transfer during the spread of crown fires and carrying out reliable theoretical modeling. In the past, when modeling the fire behavior of forest fires, people were confined to traditional thinking patterns and ignored the actual role of a large number of scattered crown leaves in the transfer of radiant energy. In the vegetation fire resistance test, the method of directly laying fallen leaves and dead branches and burning them is adopted. Not only is the test method very different from the situation where living biological fire prevention forests are attacked by heat, the observed flame characteristics and spread characteristics are also quite different from the actual fire phenomena in the wild, resulting in biased prediction results.

[0043] An embodiment of the present disclosure provides a method for detecting the thermal radiation blocking effect of plant leaves in forest fires, characterized in that the method includes: using a heating device in a detection environment to simulate the heat radiation of a fire source in a forest fire scene, using a fan to simulate the convection in the forest fire scene, and performing a thermal attack on the inspected leaves in the form of coupled thermal radiation and thermal convection, wherein the heating device is set to increase the preset temperature in cycles to create a continuously intensified thermal attack scene; determining the curling degree of the inspected leaves based on the original leaf area of ​​the inspected leaves and the vertical projection area of ​​the leaves after the thermal attack; determining the thermal radiation blocking ability of the inspected leaves at a preset temperature based on the curling degree; determining the thermal stability of the inspected leaves at a preset temperature based on the leaf mass of the inspected leaves after the thermal attack; raising the preset temperature according to a predetermined step size, detecting the thermal radiation blocking ability and thermal stability of the leaves in the continuously intensified thermal attack scene, and quantifying the thermal radiation blocking effect of the inspected leaves.

[0044] The embodiments of the present disclosure create continuously intensified external thermal attack scenarios by setting different thermal environments, quickly move the inspected leaves into a thermal environment where thermal radiation and thermal convection coexist, observe the thermal response conditions within a specific period of time, extract the curling and weight loss information of the leaves, and the system sets up a step-by-step intensified thermal attack scenario to accumulate information on the degree of curling and the rate of weight loss. The thermal response performance and fire resistance of the inspected leaves are then calibrated with the constructed detection parameters, which can effectively demonstrate the energy transmission and reception methods during the spread of fire at an actual fire scene, and is highly consistent with the actual performance and efficacy of the biological fire prevention belt at the fire scene. Compared with traditional analysis and screening methods of fire-resistant tree species based on material composition, material flammability analysis and ignition characteristics, the detection method of this embodiment is more in line with engineering practice, highly consistent with the nature of energy transfer in forest fires, and can increase the reliability of screening fire-resistant tree species in specific forest areas and promote the efficiency of ecological fire prevention work. In addition, the detection method of this embodiment starts from the energy transfer pattern at the actual fire scene, explores the impact of leaves on energy transfer in forest fires and the classification of fire promotion effects, and accordingly provides key detection methods and data support for the precise modeling of forest fire behavior.

[0045] Figure 1 The flowchart of the method for detecting the effect of plant leaves blocking heat radiation in forest fire according to an embodiment of the present disclosure is schematically shown.

[0046] like Figure 1 As shown, the method of this embodiment includes operations S110 to S150.

[0047] In operation S110, a heating device is used in the detection environment to simulate the heat radiation of the fire source in the forest fire scene, and a fan is used to simulate the convection in the forest fire scene, and a thermal attack is applied to the inspected blade in the form of coupled heat radiation and heat convection.

[0048] In operation S120 , the curling degree of the inspected blade is determined according to the original blade area of ​​the inspected blade and the vertical projection area of ​​the blade after the thermal attack.

[0049] In operation S130 , the heat radiation shielding capability of the inspected blade at a preset temperature is determined based on the curl degree.

[0050] In operation S140 , the thermal stability of the inspected blade at a preset temperature is determined based on the blade mass of the inspected blade before and after the thermal attack.

[0051] In operation S150 , the preset temperature is increased, and the thermal radiation shielding capability and thermal stability of the inspected blade are tested in a continuously intensified thermal attack scenario, so as to quantify the thermal radiation shielding effect of the inspected blade.

[0052] According to the embodiments of the present disclosure, since forest fire energy transport is primarily by thermal radiation, supplemented by thermal convection, the detection environment can be a controllable, enclosed thermal environment that couples thermal radiation and convection. A heating device can create a thermal radiation environment, and the heating device and fan can jointly create a thermal convection environment, placing the inspected blade in a thermal environment that couples radiation and convection. The detection environment includes a heating device, and the heating device is configured to periodically raise a preset temperature to create a scenario of increasingly intensified thermal attack. Specifically, the heating device can be a heating plate.

[0053] According to the embodiments of the present disclosure, the inspected blade can be fixed on a fixing device to simulate the field distribution scenario of the blades. After adjusting the thermal attack environment, the fixing device together with the inspected blade can be quickly moved into the detection environment, and the inspected blade can be placed facing the heating device.

[0054] According to an embodiment of the present disclosure, after heating for a preset time, the inspected leaf is removed from the detection environment, and the leaf area and leaf mass of the inspected leaf are collected. Specifically, the preset time can be appropriately adjusted based on the historical development of local surface fires and vertical crown fires.

[0055] According to an embodiment of the present disclosure, the thermal radiation shielding capability can represent the thermal resistance of the inspected leaf. Specifically, the thermal radiation shielding capability is related to the vertical projection area of ​​the inspected leaf. The smaller the change in the vertical projection area of ​​the leaf compared to the original leaf area, the better the thermal radiation shielding capability.

[0056] According to an embodiment of the present disclosure, the original leaf area can be the area of ​​the inspected leaf before the inspection operation is performed on the inspected leaf, and the leaf vertical projection area can be the vertical projection area of ​​the inspected leaf after the thermal attack. Specifically, the leaf area can be collected using an acquisition device such as a leaf area analyzer. When measuring the vertical projection area of ​​the heated leaf, the inspected leaf can be placed on the background plate of the leaf area analyzer after the inspected leaf cools down and photographed to ensure that the inspected leaf appears complete and clearly in the image. The position of the inspected leaf is repeatedly adjusted to ensure that the vertical projection area is maximized, and the leaf vertical projection area is measured using the leaf area analyzer.

[0057] According to embodiments of the present disclosure, the curl can be calculated from the original leaf area and the vertical projection area of ​​the leaf. The curl can be used to determine the thermal radiation shielding ability of the tree species under inspection. Specifically, the smaller the curl, the greater the thermal radiation shielding ability.

[0058] According to an embodiment of the present disclosure, thermal stability can characterize the heat resistance of the inspected blade. Specifically, thermal stability is related to the mass of the inspected blade after being subjected to thermal attack. The smaller the change in the mass of the blade, the better the thermal stability.

[0059] According to an embodiment of the present disclosure, after collecting the leaf area and leaf mass of the inspected leaf, the preset temperature can be increased, and the inspected leaf can be placed back into the inspection environment, and the inspected leaf can be subjected to a thermal attack using the preset temperature of the next round.

[0060] According to an embodiment of the present disclosure, when raising the preset temperature, the preset temperature can be increased according to a predetermined step size to obtain different preset temperatures. Specifically, the preset temperature can be increased in equal steps over J cycles, thereby increasing the thermal intensity of the thermal attack on the inspected blade. The inspected blade is then placed back into the inspection environment, and operations S110 through S140 are repeated, with the step-by-step increase reflecting the scenario where the blade is approaching the fire source. J is a positive integer.

[0061] According to the embodiments of the present disclosure, due to the influence of factors such as environmental wind, the thermal effect on a specific receptor is intermittent and continues to escalate as the flame zone approaches. Therefore, through step-by-step temperature increase, the thermal attack on the inspected blade is gradually upgraded, and a detection environment with a step-by-step increase in thermal intensity is constructed to simulate a scenario in which the inspected blade continues to approach the fire source.

[0062] According to an embodiment of the present disclosure, since the preset temperature needs to be increased in equal steps in each round, the preset temperature in round j is greater than the preset temperature in round j-1, where j is a positive integer and j ≤ J. For example, if J = 8, the predetermined step size is 20°C, and the preset temperatures for rounds 1 to 8 are 50°C, 70°C, 90°C, 110°C, 130°C, 150°C, 170°C, and 190°C, respectively, the cumulative attack time for J rounds can be 8 minutes, and the attack time for each round can be 1 minute.

[0063] According to the embodiments of the present disclosure, the heat radiation shielding effect of the inspected blade can be determined based on the heat radiation shielding capability and thermal stability of the inspected blade in each round. Specifically, the better the heat radiation shielding capability and the better the thermal stability, the stronger the heat radiation shielding effect.

[0064] According to an embodiment of the present disclosure, fire-resistant tree species for constructing a fire-resistant forest can be selected from among a plurality of tree species based on the fire-resistant performance of inspected leaves of the plurality of tree species.

[0065] According to the embodiments of the present disclosure, by setting a heating method that combines step-by-step temperature increase, thermal radiation and thermal convection, the energy transmission and reception methods during the spread of fire in an actual fire scene are effectively presented, which is highly consistent with the actual performance and efficacy of the biological fire prevention forest belt at the fire scene, conforms to the law of energy transmission in forest fires, and can find tree species with excellent thermal stability and thermal radiation shielding ability, thereby improving the accuracy of detecting the effect of plant leaves blocking thermal radiation.

[0066] Figure 2 A schematic diagram schematically illustrates a preset temperature according to an embodiment of the present disclosure.

[0067] like Figure 2 As shown, the preset temperatures for the first to eighth rounds are 50°C, 70°C, 90°C, 110°C, 130°C, 150°C, 170°C and 190°C respectively, and the thermal intensity is increased in a step-by-step manner to present a scene where the inspected blades are constantly approaching the fire source.

[0068] According to an embodiment of the present disclosure, the thermal stability of the inspected blade at a preset temperature is determined based on the leaf mass of the inspected blade after the thermal attack, including: determining the weight loss rate of the inspected blade based on the original leaf mass, original water content and leaf mass after the thermal attack of the inspected blade; and determining the thermal stability of the inspected blade at a preset temperature based on the weight loss rate.

[0069] According to an embodiment of the present disclosure, the original leaf mass may be the mass of the inspected leaf before the inspection operation is performed on the inspected leaf, and the original water content may be the water content of the inspected leaf before the inspection operation is performed on the inspected leaf. Specifically, before the inspected leaf is placed in the inspection environment, the original leaf mass of the inspected leaf can be collected using a collection device such as a balance, and the original water content of the inspected leaf can be measured.

[0070] According to embodiments of the present disclosure, the weight loss rate can be calculated from the original leaf mass, original water content, and the leaf mass after thermal stress. The weight loss rate can be used to determine the thermal stability of the tree species of the inspected leaves. Specifically, the lower the weight loss rate, the better the thermal stability.

[0071] According to an embodiment of the present disclosure, the thermal stability of the inspected blade is determined based on the mass change of the inspected blade, thereby improving the accuracy of determining the thermal stability.

[0072] According to an embodiment of the present disclosure, the j-th curling degree of the inspected blade at the j-th preset temperature can be determined based on the vertical projection area of ​​the j-th blade after the j-th round of thermal attack, and the thermal radiation shielding ability of the inspected blade at the j-th preset temperature can be determined based on the j-th curling degree.

[0073] According to an embodiment of the present disclosure, the j-th wheel curling degree can be calculated from the original leaf area and the j-th wheel leaf area. Specifically, the j-th wheel curling degree can be determined by the following formula (1):

[0074] (1)

[0075] in, is the curling degree of the inspected blade in the jth round, is the original leaf area of ​​the inspected leaf, is the vertical projection area of ​​the inspected leaf in the jth round, j ≥ 1 and j is a positive integer.

[0076] According to an embodiment of the present disclosure, the j-th round weight loss rate of the inspected blade can be determined based on the original blade mass, original water content and j-th round blade mass of the inspected blade, and the thermal stability of the inspected blade at the j-th round preset temperature can be determined based on the j-th round weight loss rate.

[0077] According to an embodiment of the present disclosure, the jth blade mass may be the mass of the inspected blade after undergoing j rounds of heating. Specifically, after the inspected blade undergoes the jth round of heating, the inspected blade is removed from the inspection environment and the mass of the inspected blade is measured using a balance to obtain the jth blade mass.

[0078] According to an embodiment of the present disclosure, the weight loss rate of the jth wheel can be calculated from the original blade mass, the original water content, and the jth wheel blade mass. Specifically, the weight loss rate is determined by the following formula (2):

[0079] (2)

[0080] in, is the weight loss rate of the inspected blade in the jth round, is the original water content of the inspected leaves, is the original leaf mass of the inspected leaf, is the leaf mass of the inspected leaf in the jth round.

[0081] In some embodiments, the curling degree of the jth wheel can be determined based on the original leaf area of ​​multiple inspected leaves of the same tree species and the leaf area of ​​the jth wheel. In this case, the curling degree calculation process can be shown as the following formula (3):

[0082] (3)

[0083] in, It can be the curling degree of the jth round of the kth inspected leaf of tree species i, can be the maximum original leaf area of ​​the kth inspected leaf of species i, It can be the maximum vertical projection area of ​​the jth leaf of the kth inspected leaf of tree species i.

[0084] According to an embodiment of the present disclosure, the heat radiation shielding capacity of tree species i can be determined based on the average maximum curl of multiple inspected leaves of tree species i. The smaller the curl, the better the heat radiation shielding capacity. Specifically, the process of determining the heat radiation shielding capacity can be shown in the following formula (4):

[0085] (4)

[0086] in, It can characterize the thermal radiation shielding ability.

[0087] In some embodiments, the j-th round weight loss rate can be determined based on the original leaf mass, original water content, and j-th round leaf mass of multiple inspected leaves of the same tree species. The number of inspected leaves of the same tree species can be five. The weight loss rate calculation process can be shown in the following formula (5):

[0088] (5)

[0089] in, is the j-th round weight loss rate of the k-th inspected leaf of species i, is the original water content of the tested leaves of species i, is the original leaf mass of the kth inspected leaf of species i, is the mass of the jth leaf wheel of the kth inspected leaf of tree species i.

[0090] According to an embodiment of the present disclosure, the thermal stability of tree species i can be determined based on the maximum average weight loss rate of multiple inspected leaves of tree species i. The smaller the weight loss rate, the better the stability. Specifically, the process of determining thermal stability can be shown in the following formula (6):

[0091] (6)

[0092] Where n is the number of inspected leaves of tree species i, Indicates thermal stability.

[0093] According to an embodiment of the present disclosure, the method for detecting the effect of plant leaves blocking heat radiation in forest fires also includes: when the preset temperature is in a first temperature range, determining the water retention of the inspected leaves at the preset temperature based on the weight loss rate; when the preset temperature is in a second temperature range, determining the anti-evaporation ability of the inspected leaves at the preset temperature based on the weight loss rate; when the preset temperature is in a third temperature range, determining the thermal stability of the main material of the inspected leaves after the moisture is basically eliminated through multiple rounds of thermal attacks at the preset temperature based on the weight loss rate and the original water content.

[0094] According to an embodiment of the present disclosure, the first temperature interval may be a temperature interval close to normal temperature, such as 50° C.–70° C., and the weight loss rate of the leaf within the first temperature interval may be used to evaluate the water retention capacity of the inspected leaf.

[0095] According to an embodiment of the present disclosure, the second temperature range can be 90°C–130°C, corresponding to the medium temperature section, which mainly highlights the thermal response of the blade under conditions close to the water evaporation temperature. Therefore, the blade weight loss rate in the second temperature range can be used to evaluate the anti-evaporation ability of the tested blade.

[0096] According to embodiments of the present disclosure, the third temperature range can be 150°C–190°C, where further weight loss can be observed. Previous studies have shown that after the blade reaches a temperature of 150°C, the chemical substances contained in the blade begin to undergo pyrolysis reactions. Based on the weight loss rate and the original moisture content, the thermal stability of the main material of the tested blade can be determined after multiple rounds of thermal attack at a preset temperature to substantially remove the moisture.

[0097] According to the embodiments of the present disclosure, by determining other characteristics of the inspected leaves in different temperature ranges, such as water retention and anti-evaporation ability, based on the characteristics of different temperature ranges, simultaneous extraction and calibration of different characteristics are achieved, thereby improving the detection efficiency and the range of characteristics covered by the calibration.

[0098] According to the embodiments of the present disclosure, to determine whether the inspected leaves are still losing water at higher temperatures, the cumulative water loss from each round of extraction can be compared with the original water content. If the former is less than the latter, it indicates that the water content of the inspected leaves has not been reduced throughout the testing process, proving that the tree species has strong water retention and excellent fire resistance.

[0099] According to an embodiment of the present disclosure, the method for detecting the effect of plant leaves blocking heat radiation in a forest fire further includes: adjusting the rotation speed of a fan to adjust the intensity of heat convection.

[0100] According to the embodiments of the present disclosure, the wind speed within the detection environment can be adjusted by adjusting the fan speed. Specifically, the wind speed is typically kept constant at 0.5 m / s to simulate a thermal wind field guided by natural convection. The wind speed can also be adjusted to adjust the intensity of thermal convection; the greater the wind speed, the greater the thermal convection intensity.

[0101] According to an embodiment of the present disclosure, the flexibility of detection is improved by controlling the intensity of heat convection using a fan.

[0102] Figure 3 The technical principle and detection process diagram according to the embodiment of the present disclosure are schematically shown.

[0103] like Figure 3 As shown, after the detection environment is adjusted, the fixing device and the inspected blade fixed by the fixing device can be moved into the detection environment using the sample delivery device, and the blade surface of the inspected blade faces the heating device.

[0104] like Figure 3 As shown, before the inspected blade is moved into the inspection environment, it can be pre-processed. Specifically, after the inspected blade is subjected to blade surface treatment, original moisture content measurement, and property parameter determination, the inspected blade is arranged in parallel on a fixing device.

[0105] like Figure 3As shown, the adjustment of the detection environment can include the setting of thermal radiation intensity and thermal convection intensity; wherein, the temperature of the thermal radiation wall and the thermal convection environment are made equal, and both can be set by the temperature control device. For example, the temperature of the heating device can be adjusted by controlling the temperature control device using a control computer to achieve a step-by-step increase in thermal intensity.

[0106] like Figure 3 As shown, after completing the jth round of heating of the test leaf, the fixture and the test leaf secured by the fixture can be quickly removed from the test environment, and the changes in the leaf's vertical projected area and mass can be measured. The test leaf can then be re-entered into the test environment at an increased thermal intensity for a cyclic test. Specifically, the duration of each heating round can be 1 minute, which can be adjusted appropriately based on the historical development of local surface fires and three-dimensional crown fires.

[0107] like Figure 3 As shown, comparative tests can be carried out on the inspected leaves of parallel groups of tree species and a detection database for storing leaf mass and leaf area can be established. The parameters of weight loss rate and curling can be calculated by computer based on the leaf area and leaf mass in the detection database. The thermal radiation shielding ability and thermal stability of the tree species can be evaluated based on the weight loss rate and curling. Accordingly, the best can be selected to find tree species with excellent shielding characteristics and thermal stability.

[0108] According to the embodiments of the present disclosure, needles exhibit a field radiation effect due to the lack of shielding effect, some broad leaves present a surface radiation with depth due to their more significant curling, and some leathery leaves will show a surface reception method from beginning to end during the invasion of forest fires, which will have a significant impact on the driving mechanism of forest fire development. The relevant tests and collected data will create conditions for major breakthroughs in the study of forest fire behavior.

[0109] According to the embodiments of the present disclosure, since a specific forest area is restricted by factors such as site conditions and climatic conditions, the broad-leaved trees that can grow do not have common characteristics. When screening relevant fire-prevention tree species, factors such as their growth habits and the density of the forest canopy must be taken into consideration, and then the detection method disclosed in this disclosure is used to accurately identify the relevant optional tree species to obtain more excellent and suitable tree species for the construction of fire-prevention forest belts. For example, comparative tests can be carried out on parallel groups of inspected leaves and a database of evaluation parameter results can be established, so that the best can be selected to find tree species with excellent shading properties and thermal stability.

[0110] An embodiment of the present disclosure provides a system for detecting the heat radiation blocking effect of plant leaves in forest fires, comprising: a box body for providing a detection environment; a heating device, arranged on the inner wall of the box body, for simulating the heat radiation of the fire source in the forest fire scene; a fan, arranged on the top of the box body, for simulating the convection in the forest fire scene; and the heating device and the fan implement a thermal attack on the inspected leaves in the form of coupled thermal radiation and thermal convection; a processing device for determining the heat radiation blocking ability of the inspected leaves at a preset temperature based on the vertical projection area of ​​the leaves after the thermal attack; determining the thermal stability of the inspected leaves at a preset temperature based on the leaf mass of the inspected leaves after the thermal attack; and adjusting the preset temperature according to a predetermined step size, and determining the heat radiation blocking ability and thermal stability of the inspected leaves at different preset temperatures, so as to evaluate the heat radiation blocking effect of the inspected leaves based on the heat radiation blocking ability and thermal stability of the inspected leaves at different preset temperatures.

[0111] According to an embodiment of the present disclosure, the box can be used to provide a closed detection environment, the fan is arranged on the top of the box, and the heating device is arranged on the inner wall of the box, which can be used to construct a stepped thermal attack environment in which heat radiation and heat convection coexist in the closed detection environment.

[0112] According to an embodiment of the present disclosure, the processing device may be a computer. Specifically, the preset temperature for each round, as well as the vertical projection area and mass of the inspected blade at the preset temperature, may be stored in the processing device. The thermal radiation shielding capability and thermal stability of the inspected blade may be determined based on the vertical projection area and mass. Furthermore, the thermal radiation shielding effect of the inspected blade may be evaluated based on the thermal radiation shielding capability and thermal stability of the inspected blade.

[0113] According to the embodiments of the present disclosure, by constructing a heating mode that combines thermal radiation and thermal convection, and using a continuously improving step-by-step heating method, a thermal attack scenario at an actual forest fire scene is simulated, which is highly consistent with the surface heating shape of leaves with typical characteristics at an actual fire scene. Compared with traditional plant fire resistance tests that require analysis of information such as ash composition, the extraction of leaf area and mass parameters in this detection method is simple, and the experimental phenomena are significant, effectively improving the reliability of the test results. No combustion phenomenon is involved in the entire test process. Compared with traditional combustion experiments, there is almost no pollutant emission, which not only eliminates the potential harm to the environment caused by the test process, but also has strong operability and is easy to implement.

[0114] According to an embodiment of the present disclosure, a guide rail is provided inside the box, and the system for detecting the effect of plant leaves blocking heat radiation in forest fires also includes: a fixing device for fixing the inspected leaves; a sample sending device, which is slidably provided on the guide rail, for clamping the fixing device and sliding along the guide rail to transport the fixing device from the outside of the box to the inside of the box, or to transport the fixing device from the inside of the box to the outside of the box.

[0115] According to an embodiment of the present disclosure, when the inspected blade is fixed by using a fixing device, the inspected blade can be placed in parallel in a vertically suspended manner, simulating the actual growth environment of the inspected blade in the wild.

[0116] According to an embodiment of the present disclosure, the sample delivery device is connected and linked to the guide rail inside the box body, so as to accurately place, transport and remove the fixing device and the inspected blade.

[0117] According to an embodiment of the present disclosure, the fixing device includes: a fixing frame; and a clamp flexibly arranged on the fixing frame for fixing the inspected blade.

[0118] According to an embodiment of the present disclosure, the clamp may be a clamp, and the petiole portion of the inspected leaf may be clamped by the clamp.

[0119] According to an embodiment of the present disclosure, a plurality of clamps may be provided on the fixing frame, and the distance between the inspected blades may be adjusted or the installed inspected blades may be ensured to be in a parallel state by adjusting the positions between the clamps.

[0120] According to an embodiment of the present disclosure, the sample delivery device includes: a crossbeam for clamping the fixing device; and a baffle for reducing heat leakage in the box during the transportation of the fixing device.

[0121] According to an embodiment of the present disclosure, a fixing device can be fixed to a crossbeam of a sample delivery device, so that the fixing device moves with the sample delivery device, transporting the inspected leaf into the box for heating, or transporting the inspected leaf from the box to the outside for leaf mass and leaf area collection. Specifically, the sample delivery device can pass through a sample inlet in the side wall of the box to achieve the transport of the inspected leaf.

[0122] According to embodiments of the present disclosure, the baffle may include an inner baffle and an outer baffle. Specifically, when the sample delivery device is located outside the housing, the inner baffle can block the sample inlet; when the sample delivery device is located inside the housing, the outer baffle can block the sample inlet to reduce heat leakage. Furthermore, the outer baffle may be provided with a handle to facilitate movement of the sample delivery device.

[0123] According to an embodiment of the present disclosure, the sample delivery device may further include a guide rod and an asbestos insulation layer, wherein the guide rod is used to connect and link with the guide rail of the box, and the asbestos insulation layer is used to keep warm and reduce heat leakage.

[0124] According to the embodiments of the present disclosure, by providing a baffle in the sample delivery device, heat leakage in the box can be reduced and detection accuracy can be improved.

[0125] According to an embodiment of the present disclosure, the system for detecting the effect of plant leaves blocking thermal radiation in forest fires also includes a collection device, which includes: a leaf area analyzer for collecting the leaf area of ​​the inspected leaves; and a balance for collecting the leaf mass of the inspected leaves.

[0126] According to an embodiment of the present disclosure, a leaf area analyzer can be used to collect the original leaf area of ​​the inspected leaf and the vertical projection area of ​​the leaf after heat attack, and a balance can be used to collect the original leaf mass and the leaf mass after heat attack.

[0127] Figure 4 The following schematically shows a system for detecting the effect of plant leaves blocking heat radiation in forest fires according to a specific embodiment of the present disclosure.

[0128] like Figure 4 As shown, the box 1 can be placed on a base 6. A heating device 9 is installed inside the box 1 to simulate a heat radiation source. A fan 12 represents the thermal convection environment 2. The input voltage control device 7 and the temperature control device 8 are used to achieve combined temperature increase and constant temperature control, creating a step-by-step thermal attack scenario. The input voltage control device 7 is connected to a power supply, and the temperature control device 8 is connected to a processing device such as a computer. The computer can control the temperature of the heating device 9 by controlling the temperature control device 8, thereby controlling the intensity of the thermal attack within the detection environment.

[0129] like Figure 4 As shown, the inspected blades 19 are suspended from a fixed frame 18 in a pre-set arrangement, closely resembling their natural growth pattern. The upper and lower guide rods of the sample delivery mechanism are connected and linked to the upper and lower guide rails 17 within the housing. The mechanism, comprised of a crossbeam 16, inner baffles 10, asbestos insulation, outer baffles 14, and a handle 15, ensure precise positioning of the fixture and allow it to be transported and removed through the sample inlet 13. The inner and outer baffles and insulation minimize heat leakage from the sample inlet 13 after opening and transport.

[0130] like Figure 4 As shown, the box 1 includes a front door 3. During the test, the front door 3 is always closed to ensure that the temperature and heat convection of the closed environment are stable. The front door window 5 on the front door 3 can be used to observe the installation status of the blades and the thermal response after the thermal attack. In addition, the front door 3 can also be provided with an insulation layer 4.

[0131] According to the embodiments of the present disclosure, Figure 4The sample delivery device currently depicts two sets, upper and lower, but this could be increased to three to increase the number of leaves tested in a single cycle. Because naturally grown leaves vary greatly in shape and size, the clamp position on the sample holder can be adjusted appropriately to ensure that all installed leaves are parallel and that their surfaces are fully aligned with the heating device 9 on the rear wall of the thermal environment.

[0132] In some embodiments, the input power of the temperature control device is 2.3 kW, the dimensions of the box are 500 mm (width) × 800 mm (height) × 360 mm (depth), the dimensions of the heating device are 490 mm (width) × 790 mm (height), the dimensions of the front door and window are 200 mm (width) × 440 mm (height), and the dimensions of the injection port are 100 mm (width) × 600 mm (height).

[0133] In a specific embodiment, several leaves are taken from different directions in a mature forest of the inspected tree species. The original moisture content of the inspected leaves is measured after wiping off dust and drying the surface moisture. Five leaves of similar shape and size are selected, numbered with a marker, tested for original leaf area, maximum leaf area and original leaf mass, and then naturally spread on a fixed bracket. The detection system is turned on and the thermal intensity is set, and the sample delivery device then delivers the inspected leaf comparison group to the correct position to create a scene where the leaves are attacked by heat under a specific intensity. After the timer 11 counts for 1 minute, the fixed bracket is removed and the inspected leaves are removed. The maximum vertical projection area and leaf mass of the inspected leaves of different tree species are detected with the help of a leaf area analyzer 20 and a precision balance 21, and the data are entered into a computer for standby use.

[0134] According to the embodiments of the present disclosure, a continuously intensifying thermal attack scenario generates heat transport in response to an approaching fire source. The temperature of the heating device and the thermal convection environment are simultaneously increased to ensure a stable attack environment. The thermal convection wind field can be regulated by a top-mounted fan. To simplify the actual fire scene, the internal wind speed is typically kept constant at 0.5 m / s to simulate the thermal wind field guided by natural convection. Thermal attack tests were repeatedly conducted on the blade assembly using the enclosed thermal environment temperature set at 50°C, 70°C, 90°C, 110°C, 130°C, 150°C, 170°C, and 190°C. A leaf area analyzer and precision balance were used to extract data on the vertically projected area and mass change of the blades under different thermal intensities. The derived calculation parameters (Formulas 1-4) were used to measure and determine the thermal radiation shielding effectiveness and fire protection characteristics of the tested samples under stepped thermal attack. The range of 50°C–70°C corresponds to near-ambient water retention; the mid-range temperature range of 90°C–130°C highlights the thermal response of leaves near water evaporation temperatures; and at higher temperatures of 150°C–190°C, further weight loss is observed, indicating the thermal stability of specific leaf chemical components. Previous studies have shown that at temperatures above 150°C, the chemical substances contained in leaves begin to undergo thermal decomposition reactions.

[0135] In one specific example, comparative testing was conducted on batches of leaves from over ten broadleaf species, including holly (Ilex chinensis), chinaberry (Melia azedarach L.), osmanthus fragrans (Thunb.) Lour.), heather (Photinia serratifolia (Desf.) Kalkman), Japanese evening cherry (Prunus serrulata var. lannesiana (Carri.) Makino), and soapberry (Sapindus saponaria Linnaeus). The collected leaves were wiped clean of dust and dried dry. Several samples were first taken from each species for moisture content testing. Then, five fresh, mature leaves from each tree species were collected and numbered 1–5. Raw leaf area and raw leaf mass were calculated. The petioles of the tested leaves were then clamped between five staggered metal clamps to maintain a parallel orientation. After the leaves were mounted, they were placed on a fixed support. Preheat the radiation and convection systems to their preset temperatures. Then quickly place the leaf under test into the chamber, automatically seal the sample inlet, and after heating for one minute, quickly remove the holder and remove the leaf sample. After cooling, place the leaf under test on the background plate of the leaf area analyzer and photograph it, ensuring that the leaf is fully and clearly visible in the image. Repeatedly adjust its position to maximize its vertical projection area. Calculate the leaf area using the leaf area analyzer. Record the mass after one minute of heating using a 1 mg precision balance.

[0136] In a specific embodiment, the preset temperatures of the testing environment are set to 50°C, 70°C, 90°C, 110°C, 130°C, 150°C, 170°C, and 190°C, respectively, and the heating time is adjustable. The disclosed embodiments can be directly used to test the radiation shielding effectiveness of leaves of different materials. Comparative experiments can be conducted on different types of tested leaves under the same site conditions and heating conditions to observe changes in curling and weight loss parameters, as well as pyrolysis, thereby determining the thermal response of the material. During the testing process, it was observed that when the thermal temperature was low, the water loss of the leaves was similar, evaporating slowly, and the leaves basically did not curl. When the temperature was slightly higher, the water in papery leaves evaporated rapidly, accompanied by rapid curling of the leaves, while leathery leaves had a stronger water retention capacity and a significantly lower curl than papery leaves. Among them, the water release period of Heather leaves was prolonged during the step-by-step thermal attack, and the water was basically evaporated at the highest temperature. The leaf shape remained basically firm and unchanged, demonstrating excellent resistance to thermal effects and the ability to shield thermal radiation. Using observed changes in leaf area and mass, as well as leaf curl and weight loss before and after testing, the radiation shielding capacity and fire resistance of leaves are measured. This allows for a clear and efficient identification and ranking of the fire-resistant properties and effectiveness of corresponding tree species. Existing tests have further confirmed that leathery wood properties offer superior fire resistance. Currently recommended fire-resistant tree species, such as Schima superba Gardner & Champ., Ilexlatifolia Thunb., and Camellia sinensis (L.) Kuntze, all fall into this same category. This understanding aligns perfectly with the recommended tree species in the industry's Forest Fire Prevention Engineering Technical Standard (LYJ 127-2012), providing a scientific basis for the selection of these species and an effective tool for further screening.

[0137] The testing site utilizes a combustion chamber with exhaust air volume in accordance with ISO 9705-1: 2016 (E) international standards. Protective equipment such as goggles, dust masks, and heat-insulating gloves are required during equipment operation and testing.

[0138] This detection method, which combines a stepped heating system with convection and radiation, effectively demonstrates the energy transfer and reception during fire spread at actual fire scenes, highly consistent with the actual performance and efficacy of biological fire prevention belts at fire scenes. Compared to traditional analysis and screening of fire-resistant tree species based on material composition, flammability, and ignition characteristics, this method is more practical for engineering practice. Based on the fundamental causes of energy transfer in forest fires, this proposed detection method and system will greatly increase the reliability of selecting fire-resistant tree species in specific forest areas and effectively improve the efficiency of ecological fire prevention efforts.

[0139] By leveraging the significant leaf area measurement and easily tracked mass, the system enables quantitative assessment of the radiation shielding effectiveness of different leaves and reliable screening of fire-resistant tree species, resulting in high scalability and applicability. Of course, the suitability of specific forestland for planting specific fire-resistant tree species depends on prior knowledge of growth and afforestation conditions, as well as the ability to achieve dense canopy formation of broad-leaved fire-resistant forest belts. High canopy density inhibits the growth of understory vegetation, automatically clearing surface combustibles.

[0140] According to the embodiments of the present disclosure, based on the construction of a standard detection method that can quantitatively identify the fire resistance of different tree species, the embodiments of the present disclosure can provide a new detection method for the fire resistance characteristics of various types of plants through observation, recording and analysis of the experimental process and experimental results. For example, digital cameras are used to capture the leaf morphology before and after heating, leaf area analyzers are used to accurately extract leaf area data, high-precision balances are used to record mass changes at different heating temperatures, comparative experiments and quantitative evaluation of fire resistance are carried out, etc.

[0141] Based on the conditions of wildfires and the design concept of non-contact fire barriers for biological fire prevention forests, different thermal attack scenarios were set up. Through multiple rounds of step-by-step thermal attack experiments, the material properties at different heating stages can be extracted and calibrated simultaneously, with outstanding advantages in both detection efficiency and the range of properties covered by calibration. Among them, 50°C–70°C corresponds to water retention near room temperature; 90°C–130°C corresponds to the medium temperature range, showing the thermal response of leaves under conditions close to the evaporation temperature of water; at the higher temperature range of 150°C–190°C, further weight loss can be observed, representing the thermal stability of the chemical components of a specific leaf group. Previous studies have shown that when leaves reach a temperature of 150°C, the chemical substances they contain begin to undergo pyrolysis reactions.

[0142] Furthermore, the inspected leaves were arranged in a vertically suspended arrangement, more closely resembling the actual leaf arrangement in fire-prevention forests. A leaf area analyzer accurately extracts leaf area at different temperatures, while a high-precision balance simultaneously records the dynamic changes in mass at different temperatures. This allows analysis of the curl and weight loss rate of leaves at specific radiation intensities. Based on the energy transport patterns observed at actual fire scenes, this study explores the impact of leaves on energy transport during forest fires and the classification of fire propulsion mechanisms, providing key detection methods and data support for the precise modeling of forest fire behavior.

[0143] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the above-mentioned module, program segment, or a part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart and the combination of boxes in the block diagram or flowchart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0144] Those skilled in the art will appreciate that the features described in the various embodiments of the present disclosure may be combined and / or coupled in various ways, even if such combinations or couplings are not explicitly described in the present disclosure. In particular, the features described in the various embodiments of the present disclosure may be combined and / or coupled in various ways without departing from the spirit and teachings of the present disclosure. All such combinations and / or couplings fall within the scope of the present disclosure.

[0145] The above describes the embodiments of the present disclosure. However, these embodiments are for illustration only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for detecting the effect of plant leaves blocking heat radiation during forest fires, characterized in that: The method comprises: Within the testing environment, a heating device is used to simulate the heat radiation from a forest fire source, and a fan is used to simulate the convection in the forest fire scenario. A thermal attack is applied to the inspected blades in a coupled form of thermal radiation and convection. The heating device is set to increase the preset temperature in cycles to create a continuously intensifying thermal attack scenario. determining the curling degree of the inspected leaf according to the original leaf area of ​​the inspected leaf and the vertical projection area of ​​the leaf after the thermal attack; determining, based on the curl degree, a heat radiation shielding capability of the inspected blade at the preset temperature; determining the thermal stability of the inspected leaf at the preset temperature according to the leaf mass of the inspected leaf after the thermal attack; According to a predetermined step size, the preset temperature is increased to determine the thermal radiation shielding ability and thermal stability of the inspected blade at different preset temperatures, so as to determine the thermal radiation shielding effect of the inspected blade based on the thermal radiation shielding ability and thermal stability of the inspected blade at the different preset temperatures.

2. The method according to claim 1, characterized in that The curl is determined by the following formula (1): （1）， in, is the curling degree of the inspected blade in the jth round, is the original leaf area of ​​the inspected leaf, is the vertical projection area of ​​the inspected blade in the jth wheel, j≥1 and j is a positive integer.

3. The method according to claim 1, characterized in that The step of determining the thermal stability of the blade to be subjected to the thermal attack at the preset temperature according to the mass of the blade to be subjected to the thermal attack comprises: The weight loss rate of the inspected leaf is determined based on the original leaf mass, the original water content, and the leaf mass after the thermal attack. The weight loss rate is determined by the following formula (2): （2）， in, is the weight loss rate of the inspected blade in the jth round, is the original water content of the inspected leaf, is the original leaf mass of the inspected leaf, is the mass of the inspected blade in the jth round; and The thermal stability of the inspected blade at the preset temperature is determined according to the weight loss rate.

4. The method according to claim 3, characterized in that The method further comprises: When the preset temperature is within a first temperature range, determining the water retention capacity of the inspected leaf at the preset temperature according to the weight loss rate; When the preset temperature is within a second temperature range, determining the anti-evaporation capability of the inspected blade at the preset temperature according to the weight loss rate; and When the preset temperature is within the third temperature range, the thermal stability of the main material of the inspected blade after the moisture is substantially eliminated after multiple rounds of thermal attacks at the preset temperature is determined based on the weight loss rate and the original moisture content.

5. The method according to claim 1, wherein The method further comprises: The speed of the fan is adjusted to adjust the intensity of the heat convection.

6. A system for detecting the effect of plant leaves blocking heat radiation during forest fires, characterized in that: The system comprises: The box is used to provide a testing environment; A heating device is provided on the inner wall of the box, and is used for radiating heat from the fire source in the simulated forest fire scene; wherein the heating device is set to increase the preset temperature in turns to create a scene of continuously intensified thermal attack; A fan is provided on the top of the box to simulate convection in a forest fire scene; and the heating device and the fan implement a thermal attack on the inspected blade in the form of coupled thermal radiation and thermal convection; A processing device is used to determine the heat radiation shielding ability of the inspected blade at the preset temperature based on the vertical projection area of ​​the leaf after the thermal attack; determine the thermal stability of the inspected blade at the preset temperature based on the leaf mass of the inspected blade after the thermal attack; and increase the preset temperature according to a predetermined step size, and determine the heat radiation shielding ability and thermal stability of the inspected blade at different preset temperatures, so as to determine the heat radiation shielding effect of the inspected blade based on the heat radiation shielding ability and thermal stability of the inspected blade at the different preset temperatures.

7. The system according to claim 6, characterized in that A guide rail is provided inside the box, and the system further comprises: A fixing device for fixing the inspected blade; The sample delivery device is slidably disposed on the guide rail, and is used to clamp the fixing device and slide along the guide rail to transport the fixing device from the outside of the box to the inside of the box, or to transport the fixing device from the inside of the box to the outside of the box.

8. The system according to claim 7, characterized in that The fixing device comprises: Fixed frame; A clamp is flexibly arranged on the fixing frame and is used to fix the inspected blade.

9. The system according to claim 7, wherein: The sample delivery device comprises: a crossbeam for fixing the fixing device; The baffle is used to reduce heat leakage in the box during the transportation of the fixing device.

10. The system according to claim 6, wherein: The system further includes a collection device, which includes: A leaf area analyzer, used for collecting the vertical projection area of ​​the inspected leaf; A balance is used to collect the leaf mass of the inspected leaf.

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