Rock-like infrared camouflage material and design method and application thereof

Abstract

The invention belongs to the technical field of camouflage materials, and relates to an infrared camouflage material based on imitation rock and a design method and application thereof. According to the design method, any rectangular area in a rock background is selected as a target surface element, and the composition of the camouflage material is determined according to the absorbed solar energy flux density of the target surface element; and obtaining a temperature change curve A of the camouflage material according to the composition of the camouflage material, calculating a difference value between the temperature change curve A of the camouflage material and an environment temperature change curve B of the rock background, and if the difference value is smaller than a preset threshold value, completing the design of the rock-imitating infrared camouflage material. The rock-imitating infrared camouflage material designed and obtained through the method can be effectively applied to thermal infrared camouflage of military targets, the temperature of the designed rock-imitating infrared camouflage material is closer to the background environment temperature, and the background integration is better.

Description

Technical Field

[0001] The invention belongs to the technical field of camouflage materials and relates to a rock-imitation infrared camouflage material and a design method and application thereof. Background Art

[0002] With the development of modern military detection technology, especially the use of infrared forward-looking systems, infrared sensor systems, and passive infrared thermal imagers, thermal infrared stealth camouflage has become increasingly difficult, and the survival and safety of various military targets are seriously threatened. Therefore, it is imperative to develop new thermal infrared stealth camouflage technologies and materials. Thermal infrared stealth camouflage technology belongs to the field of interdisciplinary technology. Through the comprehensive application of various disciplines such as material science, color science, and optics, it eliminates or reduces the target's own real thermal infrared radiation characteristics, or changes the target's thermal infrared radiation to match the background thermal infrared radiation, thereby making it difficult for infrared detection equipment to detect the target, or effectively shortening the detection distance, thereby enhancing the survivability of military targets on the battlefield.

[0003] At present, the research focus in the field of thermal infrared camouflage has always been on low-emissivity materials, especially low-emissivity coatings, but they have the following shortcomings: 1) they are difficult to be compatible with visible light, especially radar band camouflage; 2) the coating has poor tolerance to pollution, and dust and moisture can significantly increase its emissivity, resulting in the application of low-emissivity coatings being greatly limited. Phase change materials, due to their unique temperature control ability, can control the target's thermal infrared radiation intensity by regulating the temperature of the target, while overcoming the shortcomings of low-emissivity coatings, and thus have shown certain application prospects in this field. However, there is little research on thermal infrared phase change camouflage materials in China, and the limited reports are mostly focused on the research of thermal infrared camouflage phase change textiles. Therefore, it is urgent to design a thermal infrared phase change camouflage material that can be used on military targets. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a rock-like infrared camouflage material and its design method and application, which can apply phase change materials to camouflage fixed military targets and expand the application scope of phase change materials.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] On the one hand, the present invention provides a design method for a rock-imitation infrared camouflage material, which selects any rectangular area in a rock background as a target surface element, and determines the component composition of the camouflage material according to the density of the solar energy flux absorbed by the target surface element; obtains a temperature change curve A of the camouflage material according to the component composition of the camouflage material, and calculates the difference between the temperature change curve A of the camouflage material and the ambient temperature change curve B of the rock background; if the difference is less than a preset threshold, the design of the rock-imitation infrared camouflage material is completed.

[0007] Specifically, the area where the rock-imitation infrared camouflage material is placed is defined as a rectangular area, and the rectangular area is a region selected with the location of the rock-imitation infrared camouflage material as the center; the environmental background where the rock-imitation infrared camouflage material is located is defined as a rock background.

[0008] Specifically, the design method comprises the following steps:

[0009] Step 1, obtaining multiple groups of heat exchange data, each group of heat exchange data including absorbed solar energy flux density and heat exchange index value;

[0010] Step 2: constructing a calculation model for calculating the absorbed solar energy flux density based on the multiple sets of heat exchange data;

[0011] Step 3, select any rectangular area in the rock background as the target surface element;

[0012] Step 4: obtaining the heat exchange index value of the target surface element, and obtaining the absorbed solar energy flux density of the target surface element through the calculation model based on the heat exchange index value of the target surface element;

[0013] Step 5: determining the composition of the camouflage material based on the solar energy flux density absorbed by the target surface element;

[0014] Step 6: Obtain a temperature change curve A of the camouflage material according to the composition of the camouflage material;

[0015] Step 7: Obtain the ambient temperature change curve B of the rock background, calculate the difference between the temperature change curve A of the camouflage material and the ambient temperature change curve B of the rock background, and if the difference is less than a preset threshold, the design of the rock-like infrared camouflage material is completed.

[0016] Specifically, the heat transfer index values ​​in step 1 and step 4 include the convection heat transfer coefficient, the radiation heat transfer coefficient, the surface temperature of the object and the background environment temperature of the object.

[0017] Specifically, in step 2, the formula of the calculation model is as follows:

[0018] q=(α c +αr )(t w -t 0 ) Formula (1)

[0019] In formula (1), q is the absorbed solar energy flux density, α c is the convective heat transfer coefficient, α r is the radiation heat transfer coefficient, t w is the surface temperature of the object, t 0 is the temperature of the rock background environment where the object is located.

[0020] Specifically, step 5 is as follows: inputting the absorbed solar energy flux density of the target surface element into a computer, and determining the composition of the camouflage material by a Taylor series expansion method of a discrete equation, including the following steps:

[0021] Step 501: discretize the cross-section of the target surface element to obtain n nodes, where n is an integer greater than or equal to 2; wherein the concrete and the phase change material in the target surface element are separated at the mth node, where m is a positive integer less than n;

[0022] Step 502: Assuming that the temperature of the mth node and the m+1th node are equal, according to the law of conservation of energy, the calculation model of the heat absorbed by the camouflage material in the phase change region within the Δτ time is as shown in the following formula (2):

[0023]

[0024] In formula (2), Q is the heat absorbed by the phase change region material, q is the absorbed solar energy flux density of the target surface element, is the temperature of the camouflage material after a time interval of Δτ, is the temperature of the camouflage material at the initial moment, ρ is the volume density of the camouflage material, c is the specific heat capacity of the camouflage material, and Δx is the length of the phase change region;

[0025] Step 503: When the heat Q absorbed by the phase change region camouflage material is greater than or equal to pΔx, the phase change of the phase change material is completed, and the phase change heat p of the phase change material is obtained;

[0026] Step 504: Determine the composition of the camouflage material according to the phase change heat p.

[0027] Specifically, in step 7, the process of obtaining the ambient temperature change curve B of the rock background includes:

[0028] Step 701: Collect multiple environmental temperature curves of the rock background in units of days to obtain the highest temperature curve and the lowest temperature curve of the rock background;

[0029] Step 702: Add and average the highest temperature curve of the rock background and the lowest temperature curve of the rock background to obtain a median temperature curve of the rock background, and use the median temperature curve of the rock background as the ambient temperature change curve B of the rock background.

[0030] Specifically, in step 7, the preset threshold is 2°C.

[0031] On the other hand, the present invention also provides a rock-like infrared camouflage material obtained by the design method described in part or in whole as above, and its application in thermal infrared camouflage products.

[0032] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0033] A calculation model is constructed based on multiple sets of heat exchange data, and the calculation model is used to accurately calculate the solar energy flux density absorbed by the target element, and then the component composition and ratio of the camouflage material used in the target element are accurately calculated; then, the temperature change curve A of the camouflage material can be accurately simulated according to the component composition and ratio of the camouflage material, and by comparing with the ambient temperature change curve B of the rock background, it can be quickly determined whether the component ratio of the camouflage material needs to be adjusted, and then the rock-like infrared camouflage material that meets the actual infrared camouflage needs can be quickly obtained.

[0034] The rock-like infrared camouflage material designed by the present invention can be effectively applied to the thermal infrared camouflage of military targets, so that the designed rock-like infrared camouflage material is closer to the background environment temperature and has better background integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 A flow chart of a design method for a rock-like infrared camouflage material provided by the present invention;

[0038] Figure 2 is a schematic diagram of a discretized cross-section of a camouflage material provided in Example 1 of the present invention;

[0039] Figure 3 is a schematic diagram of a discretized cross-section of another camouflage material provided in Example 1 of the present invention;

[0040] Figure 4 is a cross-sectional view of a target surface element provided in Example 2 of the present invention;

[0041] Figure 5 is a curve diagram of solar energy flux density absorbed by a target surface element provided in Example 2 of the present invention;

[0042] Figure 6 A comparison curve diagram of the surface temperature of a camouflage material provided in Example 2 of the present invention and the rock background environment temperature.

[0043] Among them: 1. Concrete; 2. Mixed phase change material; 3. Maximum ambient temperature curve of rock background; 4. Minimum ambient temperature curve of rock background; 5. Median ambient temperature curve of rock background; 6. Temperature change curve A of camouflage material. DETAILED DESCRIPTION

[0044] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0045] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0046] Explanation of related terms:

[0047] 1. Heat exchange data can be obtained through experiments. When the substances measured in the experiment are different, the heat exchange data obtained are also different, that is, one substance corresponds to a set of heat exchange data. In the embodiment of the present application, multiple substances can be experimentally measured to obtain multiple sets of heat exchange data.

[0048] 2. The energy flux density of solar light absorption represents the ability of a material to absorb light, which is the solar energy vertically projected onto a unit area of ​​material per unit time.

[0049] 3. The heat transfer index value includes the convection heat transfer coefficient, the radiation heat transfer coefficient, the surface temperature of the object and the temperature of the surrounding environment. The heat transfer index value corresponding to a certain substance can be obtained through experiments, or by field measurements of the area to which the substance belongs.

[0050] Example 1

[0051] See also Figure 1 As shown, this embodiment provides a design method for a rock-like infrared camouflage material, which specifically includes the following steps:

[0052] Step 1: Acquire multiple groups of heat exchange data, each group of heat exchange data includes absorbed solar energy flux density and heat exchange index value.

[0053] Step 2: Based on multiple sets of heat exchange data, a calculation model for calculating the absorbed solar energy flux density is constructed.

[0054] It should be noted that the calculation model is a model used to reflect the relationship between the heat exchange index value and the absorbed solar energy flux density. In other words, the input of the calculation model can be the heat exchange index value, and the output can be the absorbed solar energy flux density. Through the calculation model, the absorbed solar energy flux density corresponding to certain heat exchange index values ​​can be calculated, and the calculated absorbed solar energy flux density is the absorbed solar energy flux density of the substances to which these heat exchange index values ​​belong. It is worth noting that since the calculation model has been established, when the heat exchange index value of a substance is known, the absorbed solar energy flux density of the substance can be conveniently and quickly calculated through the calculation model.

[0055] In this embodiment, the calculation model for calculating the absorbed solar energy flux density constructed based on multiple sets of heat exchange data is shown in the following formula (1):

[0056] q=(α c +α r )(t ω -t 0 ) Formula (1)

[0057] In formula (1), q is the absorbed solar energy flux density, α c is the convective heat transfer coefficient, α r is the radiation heat transfer coefficient, t w is the surface temperature of the object, t 0 is the temperature of the rock background environment where the object is located.

[0058] Step 3, select any rock-like infrared camouflage material placed in the rock background as the target surface element;

[0059] Among them, the rock background refers to the environmental background where the rock-like infrared camouflage material is located.

[0060] Step 4: obtaining the heat exchange index value of the target surface element, and obtaining the absorbed solar energy flux density of the target surface element through a calculation model according to the heat exchange index value of the target surface element;

[0061] It should be noted that the heat exchange index value of the target surface element can be obtained by field exploration of the target surface element. Further, the operation of step 4 can be: inputting the heat exchange index value of the target surface element into the calculation model, and using the output value of the calculation model as the absorbed solar energy flux density of the target surface element.

[0062] Step 5: Input the absorbed solar energy flux density of the target surface element into the computer, and determine the composition of the camouflage material through the Taylor series expansion method of the discrete equation.

[0063] Specifically, the operation of step 5 may be:

[0064] Step 501: Combination Figure 2 , discretize the cross-section of the target element to obtain n nodes, where n is an integer greater than or equal to 2; wherein the concrete and the phase change material in the target element are separated at the mth node, where m is a positive integer less than n;

[0065] Step 502: Combination Figure 3 , assuming that the temperature of the mth node and the m+1th node are equal, according to the law of conservation of energy, the calculation model of the heat absorbed by the camouflage material in the phase change area within the Δτ time is shown in the following formula (2):

[0066]

[0067] In formula (2), Q is the heat absorbed by the phase change region material, q is the absorbed solar energy flux density of the target surface element, is the temperature of the camouflage material after a time interval of Δτ, is the temperature of the camouflage material at the initial moment, ρ is the volume density of the camouflage material, c is the specific heat capacity of the camouflage material, and Δx is the length of the phase change region;

[0068] Step 503: When the heat Q absorbed by the phase change region camouflage material is greater than or equal to pΔx, the phase change of the phase change material is completed, and the phase change heat p of the phase change material is obtained;

[0069] Step 504: Determine the composition of the camouflage material according to the phase change heat p.

[0070] It should be noted that the composition of the camouflage material is determined according to the phase change heat p, specifically:

[0071] Solve by hypothesis method and equation group, that is, establish multiple equation groups based on the law of conservation of energy to solve; or, you can use professional software to assist analysis such as Materials Studio to analyze. These software can simulate and analyze the composition of materials based on the input phase change heat data and other related physical and chemical properties, combined with the built-in material database and algorithm of the software.

[0072] For example, the measured material phase change heat, temperature range and other parameters are input into the software, and the software will search for matching component combinations in its material library and give possible component compositions and corresponding proportion ranges. This method can greatly improve the efficiency and accuracy of analysis, especially for complex multi-component materials.

[0073] Combined with the experience in the actual design process, preferably, this embodiment also uses computer programming calculation + software analysis, that is, using C++ and Matlab to obtain possible component compositions and corresponding proportion ranges that meet the conditions.

[0074] Step 6: Obtain a temperature variation curve A of the camouflage material according to the composition of the camouflage material.

[0075] Step 7, obtaining the ambient temperature change curve B of the rock background, calculating the difference between the temperature change curve A of the camouflage material and the ambient temperature change curve B of the rock background, and if the difference is less than a preset threshold, the design of the rock-imitation infrared camouflage material is completed;

[0076] Specifically, the operation of step 7 may be:

[0077] Step 701: Collect multiple environmental temperature curves of the rock background in units of days to obtain the highest temperature curve and the lowest temperature curve of the rock background;

[0078] Step 702: Add and average the highest temperature curve of the rock background and the lowest temperature curve of the rock background to obtain a median temperature curve of the rock background, and use the median temperature curve of the rock background as the ambient temperature change curve B of the rock background;

[0079] Step 703, calculate the difference between the temperature change curve A of the camouflage material and the ambient temperature change curve B of the rock background. When the difference is less than 2°C, it indicates that there is a small temperature difference between the surface temperature of the camouflage material and the rock background, and the design of the rock-like infrared camouflage material is completed.

[0080] Example 2

[0081] This embodiment provides another design method of a rock-like infrared camouflage material. The design principle is the same as that of Embodiment 1, except that:

[0082] ① Select any rock-like infrared camouflage material in the rock background as the target surface element, see Figure 4 The surface layer is a 2cm thick concrete 1, and below the concrete 1 is a layer of mixed phase change material 2, and below the mixed phase change material 2 is thermally insulated. Among them, the thermal conductivity of concrete 1 is 1.33W / (m·k) and the specific gravity is 2.3g / cm 3 , heat capacity is 960 J / (kg·K); the thermal conductivity of the mixed phase change material 2 is 0.496 W / (m·k) and the density is 1.2 g / cm 3 , the heat capacity is 1.25kJ / (kg·K).

[0083] ②The absorption solar energy flux density curve of the above target surface element is shown in Figure 5 , the calculation time is from 6 am to 6 pm. Figure 5 It can be found that the change of solar energy flux density absorbed by the target surface element during the day can be approximated by a quartic curve.

[0084] ③ Through the Taylor series expansion method of the discrete equation, the composition of the mixed phase change material 2 used in the target element is determined as shown in Table 1.

[0085] Table 1 Properties and contents of various components in camouflage materials

[0086] serial number Phase change temperature / ℃ Phase change heat / (J / g) Content / wt% (weight percentage) 1 24 190 20 2 26.5 205 15 3 29.2 243.5 12 4 32.6 156 8

[0087] ④ Figure 6 The figure is a comparison curve of the surface temperature of the camouflage material and the ambient temperature change; among them, 3 is the highest ambient temperature curve of the rock background (the solid line curve 3 is marked with "□"); 4 is the lowest ambient temperature curve of the rock background (the solid line curve 4 is marked with "△"); 5 is the median ambient temperature curve of the rock background (dashed line curve); 6 is the temperature change curve A of the camouflage material. Figure 6 It can be seen that the surface temperature of the camouflage material in this embodiment varies around the middle value of the rock background ambient temperature, with a variation deviation of no more than 2°C, and the surface temperature of the camouflage material is all between the highest and lowest temperatures of the rock background, meeting the infrared camouflage requirements.

[0088] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0089] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A design method for rock-like infrared camouflage material, characterized in that: An arbitrary rectangular area in the rock background is selected as the target surface element, and the composition of the camouflage material is determined according to the density of the solar energy flux absorbed by the target surface element; the temperature change curve A of the camouflage material is obtained according to the composition of the camouflage material, and the difference between the temperature change curve A of the camouflage material and the ambient temperature change curve B of the rock background is calculated. If the difference is less than a preset threshold, the design of the rock-like infrared camouflage material is completed.

2. The design method of the rock-like infrared camouflage material according to claim 1 is characterized in that: The area where the rock-like infrared camouflage material is placed is defined as a rectangular area, and the rectangular area is a region selected with the location of the rock-like infrared camouflage material as the center; the environmental background where the rock-like infrared camouflage material is located is defined as a rock background.

3. The design method of the rock-like infrared camouflage material according to claim 2 is characterized in that: The specific steps include: Step 1, obtaining multiple groups of heat exchange data, each group of heat exchange data including absorbed solar energy flux density and heat exchange index value; Step 2: constructing a calculation model for calculating the absorbed solar energy flux density based on the multiple sets of heat exchange data; Step 3, select any rectangular area in the rock background as the target face element; wherein the area where the rock-like infrared camouflage material is placed is defined as a rectangular area, and the rectangular area is a region selected with the location of the rock-like infrared camouflage material as the center; define the environmental background where the rock-like infrared camouflage material is located as the rock background; Step 4: obtaining the heat exchange index value of the target surface element, and obtaining the absorbed solar energy flux density of the target surface element through the calculation model based on the heat exchange index value of the target surface element; Step 5: determining the composition of the camouflage material based on the solar energy flux density absorbed by the target surface element; Step 6: Obtain a temperature change curve A of the camouflage material according to the composition of the camouflage material; Step 7: Obtain the ambient temperature change curve B of the rock background, calculate the difference between the temperature change curve A of the camouflage material and the ambient temperature change curve B of the rock background, and if the difference is less than a preset threshold, the design of the rock-like infrared camouflage material is completed.

4. The design method of the rock-like infrared camouflage material according to claim 3 is characterized in that: The heat transfer index values ​​in step 1 and step 4 include the convection heat transfer coefficient, the radiation heat transfer coefficient, the surface temperature of the object and the background environment temperature of the object.

5. The design method of the rock-like infrared camouflage material according to claim 3 is characterized in that: In step 2, the formula of the calculation model is as follows: q = (α c + α r )(t w - t0) Equation (1) In formula (1), q is the absorbed solar energy flux density, α c is the convective heat transfer coefficient, α r is the radiation heat transfer coefficient, t w is the surface temperature of the object, and t0 is the background temperature of the rock where the object is located.

6. The design method of the rock-like infrared camouflage material according to claim 3 is characterized in that: Step 5 is specifically: inputting the absorbed solar energy flux density of the target surface element into a computer, and determining the composition of the camouflage material by the Taylor series expansion method of the discrete equation, including the following steps: Step 501: discretize the cross-section of the target element to obtain n nodes, where n is an integer greater than or equal to 2; wherein the concrete and the phase change material in the target element are separated at the mth node, where m is a positive integer less than n; Step 502: Assuming that the temperature of the mth node and the m+1th node are equal, according to the law of conservation of energy, the calculation model of the heat absorbed by the camouflage material in the phase change region within the Δτ time is as shown in the following formula (2): In formula (2), Q is the heat absorbed by the phase change region material, q is the absorbed solar energy flux density of the target surface element, is the temperature of the camouflage material after a time interval of Δτ, is the temperature of the camouflage material at the initial moment, ρ is the volume density of the camouflage material, c is the specific heat capacity of the camouflage material, and Δx is the length of the phase change region; Step 503: When the heat Q absorbed by the phase change region camouflage material is greater than or equal to pΔx, the phase change of the phase change material is completed, and the phase change heat p of the phase change material is obtained; Step 504: Determine the composition of the camouflage material according to the phase change heat p.

7. The design method of the rock-like infrared camouflage material according to claim 3 is characterized in that: Step 7, the process of acquiring the ambient temperature variation curve B of the rock background includes: Step 701: Collect multiple environmental temperature curves of the rock background in units of days to obtain the highest temperature curve and the lowest temperature curve of the rock background; Step 702: Add and average the highest temperature curve of the rock background and the lowest temperature curve of the rock background to obtain a median temperature curve of the rock background, and use the median temperature curve of the rock background as the ambient temperature change curve B of the rock background.

8. The design method of the rock-like infrared camouflage material according to claim 3 is characterized in that: In step 7, the preset threshold is 2°C.

9. A rock-like infrared camouflage material, characterized in that: Obtained by applying the design method described in any one of claims 1 to 8 above.

10. Use of the rock-like infrared camouflage material designed based on the design method described in any one of claims 1 to 8 in thermal infrared camouflage products.

Images