Underground engineering thermal infrared characteristic suppression method based on thermal insulation and temperature control

Abstract

The invention provides an underground engineering thermal infrared characteristic suppression method based on thermal insulation and temperature control. The underground engineering thermal infrared characteristic inhibition method comprises the following steps that S1, a flue gas emission model used for an underground engineering target area is constructed, the flue gas emission model comprises a flue, and a thermal insulation layer and a rock-soil layer are sequentially arranged outside the flue; s2, acquiring parameters of a heat insulation layer through conjugate heat transfer analogue simulation, and enabling the temperature difference between an outlet of the flue and a surrounding rock-soil layer to be not greater than 2K; and S3, a temperature control system is arranged on the outer side of the heat insulation layer, the temperature of the flue is adjusted through the temperature control system, and the temperature difference between an outlet of the flue and the surrounding rock-soil layer is controlled to be not larger than 2K. The underground engineering thermal infrared characteristic inhibition method can well meet specific thermal insulation and temperature control requirements under different environment conditions, the underground engineering thermal infrared characteristic inhibition capability is remarkably improved, intelligent temperature control and dynamic adjustment are achieved, and good economic benefits and social benefits are achieved.

Description

Technical Field

[0001] The invention relates to the field of underground engineering safety technology, and in particular to a method for suppressing thermal infrared characteristics of underground engineering based on heat insulation and temperature control. Background Art

[0002] With the continuous development of infrared detection technology, the safety and concealment of underground projects such as underground military facilities, underground pipelines, underground transportation facilities, etc. are facing increasing challenges. Due to their special structure and operating environment, underground projects often generate a lot of heat and dissipate it through the surface, forming obvious thermal infrared characteristics that are easily discovered and identified by infrared detectors. Therefore, reducing the thermal infrared characteristics of underground projects and improving their concealment are of great significance to ensure the safety of underground projects.

[0003] Thermal insulation and temperature control technology is the core of thermal infrared feature suppression technology for underground projects. Thermal insulation and temperature control are mainly achieved by using thermal insulation materials, optimizing structural design, and using refrigeration equipment. The use of thermal insulation materials on the surface or inside of underground engineering structures can reduce the transfer and loss of heat, and the optimization of the design of underground engineering structures can improve the overall thermal insulation performance of the structure. Installing refrigeration equipment inside the underground project and lowering the temperature of the structure through active cooling can quickly reduce the temperature, but it usually consumes a lot of energy and maintenance costs.

[0004] Infrared feature suppression technology is a means of further reducing the infrared radiation characteristics of underground projects based on thermal insulation and temperature control technology. Infrared feature suppression is mainly achieved through surface radiation control technology, thermal camouflage pattern technology, and comprehensive control technology. By coating the surface of underground engineering structures with infrared low-emissivity materials, the infrared emissivity of the surface can be reduced, thereby reducing the infrared characteristics of underground projects. The thermal camouflage pattern prepared by combining high and low emissivity materials can segment large-area infrared thermal images, allowing underground engineering structures to merge with the background, which can effectively reduce the recognition rate of infrared detectors for target objects and improve the concealment of underground projects.

[0005] Although existing technologies have made some progress in thermal insulation, temperature control and infrared feature suppression, they still have certain limitations in terms of material performance limitations, cost and maintenance issues, and environmental adaptability. The performance of thermal insulation materials and infrared low-emissivity materials directly affects the effects of thermal insulation, temperature control and infrared feature suppression; however, the types and performance of materials currently available on the market are limited, and it is difficult to meet the needs of all underground projects. In addition, the environment of underground projects is complex and changeable, such as temperature, humidity, soil conditions, etc., which will affect thermal insulation, temperature control, and infrared feature suppression technology. Therefore, customized design and implementation are required for different environmental conditions.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a method for suppressing thermal infrared characteristics of underground engineering based on thermal insulation and temperature control, which significantly improves the ability to suppress thermal infrared characteristics of underground engineering and realizes intelligent temperature control and dynamic adjustment.

[0008] The present invention provides a method for suppressing thermal infrared characteristics of underground engineering based on heat insulation and temperature control, comprising the following steps:

[0009] S1: construct a smoke emission model for the target area of ​​the underground project, the smoke emission model includes a smoke duct, and an insulation layer and a rock and soil layer are sequentially arranged outside the smoke duct;

[0010] S2: Obtain the insulation layer parameters through conjugate heat transfer simulation so that the temperature difference between the flue outlet and the surrounding rock and soil layer is no more than 2K;

[0011] S3: A temperature control system is set on the outside of the insulation layer, and the temperature of the flue is adjusted by the temperature control system to control the temperature difference between the flue outlet and the surrounding rock and soil layer to be no more than 2K.

[0012] For the scenario where the outside of the flue is mountain rock, when the high-temperature flue gas flows through the flue, the flue will have a strong heat exchange with the surrounding rock mass, causing the temperature of the surrounding rock mass to rise; on the one hand, under the action of the long-term high temperature field, the rock mass will undergo significant deformation, cracking, or even destruction, which will become a key issue affecting the safety of the project; on the other hand, the excessively high temperature of the external rock mass will become an important target for infrared detection. Therefore, by wrapping a certain thickness of insulation layer on the outer wall of the flue, the heat in the flue is prevented from being transferred to the rock mass, so as to produce a heat insulation effect.

[0013] The underground engineering thermal infrared feature suppression method of the present invention first designs and constructs a smoke emission model for the target area of ​​the underground engineering based on the above-mentioned method. After the smoke emission model reaches the design goal of making the temperature difference between the flue outlet and the surrounding rock and soil layer no more than 2K, construction is carried out in the target area of ​​the underground engineering according to the smoke emission model, which can well meet the specific thermal insulation and temperature control requirements under different environmental conditions.

[0014] In step S1, the flue gas emission model may include multiple flues arranged at horizontal intervals, and multiple flues arranged at horizontal intervals are conducive to reducing the thermal infrared characteristics of underground projects and improving the concealment of underground projects. The cross-sectional shape of the flue can be circular or straight-walled circular arched, and the straight-walled circular arched shape includes a rectangle and a semicircle located above the rectangle, and the upper side length of the rectangle constitutes the diameter of the semicircle; wherein the aspect ratio of the rectangle is 1:2. There is no strict restriction on the number and size of the flues, which can be reasonably determined based on relevant parameters such as the smoke exhaust volume.

[0015] When constructing a heat insulation model of a metal exhaust duct with a circular cross-section, the metal exhaust duct model includes a metal layer and a heat insulation layer, and the metal exhaust pipe is buried in the surrounding rock and soil layer. When constructing a heat insulation model of a straight wall round arch exhaust duct with a straight wall round arch cross-section, the upper part is a semicircular cylinder wall, which involves the heat conduction problem of the cylinder wall; the lower part is a rectangular flat wall, which involves the heat conduction problem of the flat wall; therefore, the heat insulation effect of the heat insulation layer of the outer wall of the flue can be theoretically analyzed by using the flat wall heat conduction and the cylindrical wall heat conduction methods respectively.

[0016] Step S2 specifically includes:

[0017] A) Parametric modeling of flue, insulation layer, and geotechnical layer;

[0018] B) Perform finite element meshing on the flue;

[0019] C) Perform conjugate heat transfer simulation based on material parameters and boundary conditions to extract temperature data of flue, insulation layer and rock and soil layer;

[0020] D) Analyze the temperature data. If the temperature difference requirements are met, the design is completed. If not, adjust the insulation layer parameters until the temperature difference requirements are met.

[0021] In step A), the flue, insulation layer, and rock and soil layer parameters include flue diameter, flue length, insulation layer thickness, insulation layer wrapping length, rock and soil layer thickness, rock and soil layer depth, and other parameters.

[0022] In step C), the material parameters include density, thermal conductivity, specific heat capacity, etc., and the boundary conditions include parameters such as inlet boundary conditions, outlet boundary conditions, and wall boundary conditions.

[0023] The insulation layer parameters include at least one of the insulation layer material, the insulation layer thickness and the insulation layer wrapping length. The insulation layer wrapping length refers to the length of the insulation layer wrapped outside the flue from the flue outlet to the flue gas inlet. The insulation layer material, insulation layer thickness and insulation layer wrapping length can be selected based on relevant parameters such as the exhaust volume, and then continuously optimized through conjugate heat transfer simulation until the temperature difference between the flue outlet and the surrounding rock and soil layer is no more than 2K.

[0024] Specifically, the material of the thermal insulation layer (also called thermal insulation material) is selected from at least one of rock wool, foam glass, aerogel, porous ceramics, vacuum insulation panels and modified polypropylene insulation panels; the above-mentioned thermal insulation materials have extremely low thermal conductivity and high thermal resistance, which can effectively block the heat transfer path; according to the actual situation and needs of the underground project, the thermal insulation material is customized, such as adjusting the thickness, shape and size of the material to meet specific thermal insulation and temperature control requirements. The thickness of the thermal insulation layer is ≤100mm, and the thickness of the thermal insulation layer should not be too thick to avoid damage to the structure of the underground project. The insulation layer wrapping length can be 5-10m.

[0025] The thermal insulation layer can be made of a single thermal insulation material, or it can be formed into a composite thermal insulation layer (i.e., a multi-layer thermal insulation structure) by stacking thermal insulation materials with different properties to more effectively block the transfer of heat and improve the thermal insulation and temperature control effects; in addition, an air interlayer or a vacuum layer can be set in the multi-layer thermal insulation structure to further reduce the thermal conductivity and enhance the thermal insulation performance.

[0026] In addition, the thickness of the rock layer can be 80-120m, the depth can be 200-220m, and the depth of the external environment can be 80-120m.

[0027] The data obtained by conjugate heat transfer simulation can be fitted into the temperature distribution curve of each flue mouth, and then the temperature change law of the flue mouth can be obtained; on this basis, the optimal laying plan and parameters of the insulation layer can be obtained, and then the optimal insulation measures to control the temperature difference between the flue mouth and the surrounding rock mass to no more than 2K can be determined.

[0028] In step S3, the temperature control system includes a temperature monitoring unit and a temperature adjustment unit, and the temperature adjustment unit includes a refrigeration device and / or a heating device. An intelligent temperature control system is introduced to monitor the temperature and infrared radiation characteristics of the underground project in real time through the temperature monitoring unit, and automatically adjust the performance and state of the thermal insulation and temperature control materials through the temperature adjustment unit according to the monitoring results. The intelligent temperature control system can be combined with the ventilation, lighting and other systems of the underground project to achieve coordinated control and optimized operation.

[0029] Furthermore, the outer surface of the heat insulation layer may be coated with an infrared low emissivity material, which may be made of polyurethane, aluminum composite fiber, and other materials. By coating the surface of the underground engineering structure with an infrared low emissivity material, the infrared emissivity of the surface can be reduced; the infrared low emissivity material has a low emissivity and can reduce the emittance of infrared radiation. Selecting an infrared low emissivity material that matches the background environment of the underground engineering structure can achieve a better stealth effect.

[0030] According to the research status and existing problems of the temperature field and thermal insulation measures at the flue mouth, and combined with the actual project, the present invention constructs a metal exhaust duct insulation model and a straight wall arch exhaust duct insulation model, respectively adopts the flat wall heat conduction algorithm and the cylindrical wall heat conduction algorithm for the two models, and establishes a thermal insulation and temperature control technology simulation method; at the same time, through the parametric modeling of the flue, the insulation layer, and the rock and soil layer, the overall flue is meshed, and the simulation calculation is simulated by the CHT (conjugate heat transfer) method. By adjusting the parameters of the insulation layer, it is ensured that the temperature difference of the final rock and soil layer outlet section does not exceed 2K, and finally determines the material, thickness, wrapping length and other related parameters of the insulation layer. In addition, the temperature and infrared radiation characteristics of the underground project are monitored in real time through the intelligent temperature control system, and the performance and state of the thermal insulation and temperature control material are automatically adjusted according to the monitoring results. The temperature difference between the outlet of the flue and the surrounding rock and soil layer can be stably controlled to be no more than 2K, which not only realizes intelligent temperature control and dynamic adjustment, but also significantly improves the ability to suppress the thermal infrared characteristics of the underground project, and can well meet the specific thermal insulation and temperature control requirements under different environmental conditions.

[0031] The present invention can solve the following technical problems:

[0032] 1. Significant problems of thermal infrared characteristics of underground projects

[0033] Underground projects, especially underground continuous walls, tunnels and other structures, have significant thermal infrared characteristics due to their special geographical location and structural characteristics. These characteristics are easily captured and identified by infrared detectors, thereby exposing the location and status of the project and posing a threat to the safety and concealment of the project. Therefore, the present invention aims to effectively reduce the thermal infrared characteristics of underground projects and improve their concealment through thermal insulation and temperature control technology.

[0034] 2. Thermal insulation and temperature control materials and technology selection issues

[0035] In the process of solving the significant problem of thermal infrared characteristics of underground projects, it is crucial to choose suitable thermal insulation and temperature control materials and technologies. According to the actual situation and needs of underground projects, the present invention selects materials with excellent thermal insulation performance, good stability and convenient construction, designs reasonable thermal insulation and temperature control solutions, and takes into account factors such as material cost and environmental protection to ensure the economy and sustainability of the technology.

[0036] 3. Balance between thermal infrared feature suppression effect and engineering safety

[0037] While reducing the thermal infrared characteristics of underground projects, the safety and stability of the projects must be ensured; while ensuring the thermal insulation and temperature control effects, the present invention avoids damage to the structure of the underground project, ensuring that it can withstand various loads and deformations; at the same time, the impact of thermal insulation and temperature control technology on the environment is taken into consideration to avoid pollution and damage to the ecological balance.

[0038] The implementation of the present invention has at least the following advantages:

[0039] 1. Significantly improve thermal infrared feature suppression capabilities

[0040] The present invention adopts high-performance insulation materials and a rationally designed insulation layer structure, which can significantly reduce the thermal infrared radiation characteristics of underground projects, thereby improving their concealment and safety; compared with traditional technologies, the present invention has a stronger ability to suppress thermal infrared characteristics and can more effectively prevent underground projects from being discovered by detection equipment such as infrared detectors.

[0041] 2. Realize intelligent temperature control and dynamic adjustment

[0042] The present invention introduces an intelligent temperature control system that can monitor the temperature and infrared radiation characteristics of underground projects in real time, and automatically adjust the performance and status of thermal insulation and temperature control materials according to the monitoring results. This intelligent temperature control and dynamic adjustment mechanism makes the temperature control of underground projects more precise and stable, and improves the overall thermal management efficiency.

[0043] 3. Improve construction efficiency and simplicity

[0044] The present invention can adopt a modular construction method to assemble thermal insulation and temperature control materials and equipment into standardized modules, which are convenient for rapid installation and disassembly. This not only reduces the construction difficulty and cost, but also improves the construction efficiency and quality, making the thermal infrared feature suppression technology of underground projects easier to promote and apply.

[0045] 4. Beneficial Economic Effects

[0046] Through efficient heat insulation and temperature control technology, the present invention can significantly reduce the energy consumption of underground projects, reduce the operating time and energy consumption of refrigeration equipment or heating equipment; at the same time, due to the use of high-performance heat insulation materials, it also reduces the consumption of raw materials and reduces the overall cost. The heat insulation and temperature control technology of the present invention can protect the structural stability of underground projects, reduce structural deformation and damage caused by temperature changes, and is conducive to extending the service life of underground projects and reducing maintenance and replacement costs.

[0047] V. Social Benefits

[0048] For military underground projects, the present invention can significantly improve their concealment and safety, help enhance national defense security, and is of great significance for maintaining national security and stability. By reducing the energy consumption of underground projects and reducing the operating time of refrigeration or heating equipment, it helps to reduce environmental pollution and carbon emissions, which is in line with the current global trend of environmental protection and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 It is a structural schematic diagram of the metal exhaust duct insulation model;

[0051] Figure 2 This is a structural diagram of a straight wall round arch flue;

[0052] Figure 3 This is a structural schematic diagram of the straight wall round arch smoke exhaust duct insulation model;

[0053] Figure 4 This is the flow chart of thermal insulation and temperature control analysis.

[0054] Description of reference numerals:

[0055] 11: metal layer; 12: insulation layer; 13: rock and soil layer; 14: flue gas; 21: straight wall arch flue; 22: insulation layer; 23: rock and soil layer; 24: flue gas. DETAILED DESCRIPTION

[0056] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0057] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0058] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Example 1

[0060] The method for suppressing thermal infrared characteristics of underground engineering based on heat insulation and temperature control in this embodiment includes the following steps:

[0061] S1: Constructing smoke emission model

[0062] The flue gas emission model includes a plurality of flues and a heat insulation layer and a rock and soil layer sequentially arranged outside each flue, and the plurality of flues are arranged at intervals horizontally.

[0063] like Figure 1 As shown, in one embodiment, the flue can adopt a metal smoke exhaust duct insulation model with a circular cross-section shape. At this time, the metal smoke exhaust duct model includes a metal layer 11 and an insulation layer 12. A rock and soil layer 13 is arranged outside the insulation layer 12, and the smoke 14 flows in the metal layer 11.

[0064] like Figure 2 As shown, in another embodiment, the flue can be a straight-walled round-arch flue 21; Figure 3 As shown in the figure, a straight wall round arch smoke exhaust duct insulation model with a straight wall round arch cross-section is constructed. The straight wall round arch smoke exhaust duct insulation model includes a straight wall round arch smoke exhaust duct 21, an insulation layer 22 arranged outside the straight wall round arch smoke exhaust duct 21, and a rock layer 23 arranged outside the insulation layer 22. Smoke 24 flows in the straight wall round arch smoke exhaust duct 21. The upper part of the straight wall round arch smoke exhaust duct insulation model is a semicircular cylinder wall, which involves the problem of cylinder wall heat conduction; the lower part is a rectangular flat wall, and the aspect ratio of the rectangular flat wall is 1:2, which involves the problem of flat wall heat conduction. The heat insulation effect of the heat insulation layer of the outer wall of the smoke exhaust duct is theoretically analyzed by flat wall heat conduction and cylindrical wall heat conduction. In addition, since the straight wall round arch smoke exhaust duct is led out from the side of the smoke exhaust duct, the local resistance loss at the connection needs to be considered, so the smoke exhaust duct geometry at the connection needs to be retained (the retained length is 30m). There is no strict restriction on the number and size of smoke exhaust ducts, which can be reasonably determined according to relevant parameters such as smoke exhaust volume.

[0065] S2: Conjugate Heat Transfer Simulation

[0066] Combination Figure 4 As shown, firstly, the flue, insulation layer and rock soil layer are parametrically modeled, and the parameters include the thickness of the insulation layer, the length of the insulation layer wrapping, etc.; then, the flue is meshed by finite element; according to the material parameters and boundary conditions (including the conduction parameters of the insulation layer, etc.), the conjugate heat transfer simulation is carried out, and the temperature data of the flue, insulation layer and rock soil layer are extracted. The temperature data are analyzed, and if the temperature difference requirement is met (even if the temperature difference between the flue outlet and the surrounding rock soil layer is not greater than 2K), the design is completed; if the temperature difference requirement is not met, the insulation layer parameters are adjusted until the temperature difference requirement is met.

[0067] The insulation layer parameters include the insulation layer material, insulation layer thickness and insulation layer wrapping length. The insulation layer parameters are first selected and designed according to relevant parameters such as smoke exhaust volume, and then continuously optimized through conjugate heat transfer simulation until the insulation layer parameters can meet the temperature difference between the flue outlet and the surrounding rock and soil layer is no more than 2K.

[0068] The thermal insulation layer can be made of rock wool, foam glass, aerogel, porous ceramics, vacuum insulation panels, modified polypropylene insulation panels, etc. The thickness of the thermal insulation layer is controlled to be ≤100mm; the thermal insulation layer wrapping length is designed to be 5-10m. The thermal insulation layer can be formed into a composite thermal insulation layer by stacking thermal insulation materials with different properties (such as different thermal conductivity coefficients, etc.); in addition, an air interlayer or a vacuum layer can be set in the composite thermal insulation layer to further reduce the thermal conductivity and enhance the thermal insulation performance.

[0069] The thickness of the rock layer can be 80-120m, for example, 100m; the depth can be 200-220m, for example, 210m; the depth of the external environment can be 80-120m, for example, 100m, and the surface not wrapped by the rock mass is set as an insulating wall surface. The outlet rock layer can be set in two ways: full wrapping and semi wrapping; among them, the full wrapping method means that the outer surface of the flue is completely covered without leaving any unwrapped part; the semi wrapping method means that part of the outer surface of the flue is wrapped, while the other part remains naturally exposed.

[0070] In addition, a geometric model of the ambient space around the flue outlet can be added to eliminate the error caused by the unknown surface heat exchange coefficient between the rock mass, insulation layer and concrete flue at the outlet and the environment; the geometric model includes the flue outlet itself, determines the size and shape of the outlet cross section, and the direction of the outlet, and then expands a certain distance around to cover the area significantly affected by the flue outlet.

[0071] The data obtained by conjugate heat transfer simulation was fitted into the temperature distribution curves of each flue mouth, and the temperature change law of the flue mouth was obtained; on this basis, the optimal laying plan and parameters of the insulation layer were obtained, and then the optimal insulation measures were determined to control the temperature difference between the flue mouth and the surrounding rock mass to no more than 2K.

[0072] In addition, the outer surface of the thermal insulation layer can be coated with infrared low-emissivity materials, such as polyurethane, aluminum composite fiber, etc., and the coating thickness of the infrared low-emissivity materials is generally in the range of 0.05-2mm. Selecting infrared low-emissivity materials that match the background environment of underground projects can achieve better stealth effects.

[0073] S3: Setting the temperature control system

[0074] A temperature control system is set outside the insulation layer, and the temperature control system includes a temperature monitoring unit and a temperature regulating unit, and the temperature regulating unit includes a refrigeration device and / or a heating device. The temperature and infrared radiation characteristics of the underground project are monitored in real time by the temperature monitoring unit, and the performance and state of the thermal insulation and temperature control material are automatically adjusted by the temperature regulating unit according to the monitoring results, so that the temperature difference between the flue outlet and the surrounding rock and soil layer is stably controlled to be no more than 2K.

[0075] Example 2

[0076] This embodiment is a specific example of the method of embodiment 1; specifically, the cross-sectional shape of the flue is a straight wall round arch, the height of the straight wall round arch rectangle is 1.75m, the width is 3.5m, and the diameter of the semicircle above the rectangle is consistent with the width of the rectangle. The rock layer is fully wrapped, the total length of the flue is 200m, the insulation layer material is rock wool, the thickness of the insulation layer is preferably 14.4mm, the insulation layer wrapping length is consistent with the total length of the flue, the rock layer radius is 100m, the rock layer depth is 210m, the infrared low emissivity material is polyurethane, and the coating thickness of the infrared low emissivity material is 0.1mm.

[0077] The test results show that the underground engineering thermal infrared feature suppression method of this embodiment can stably control the temperature difference between the flue outlet and the surrounding rock and soil layer to no more than 2K, and has an excellent underground engineering thermal infrared feature suppression effect.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for suppressing thermal infrared characteristics of underground engineering based on thermal insulation and temperature control, characterized in that: The steps include: S1: construct a smoke emission model for the target area of ​​the underground project, the smoke emission model includes a smoke duct, and an insulation layer and a rock and soil layer are sequentially arranged outside the smoke duct; S2: Obtain the insulation layer parameters through conjugate heat transfer simulation so that the temperature difference between the flue outlet and the surrounding rock and soil layer is no more than 2K; S3: A temperature control system is set on the outside of the insulation layer, and the temperature of the flue is adjusted by the temperature control system to control the temperature difference between the flue outlet and the surrounding rock and soil layer to be no more than 2K.

2. The method for suppressing thermal infrared characteristics of underground engineering according to claim 1, characterized in that: The flue gas emission model includes a plurality of flues arranged at intervals horizontally; the cross-sectional shape of the flue is circular or straight-walled circular arch.

3. The method for suppressing thermal infrared characteristics of underground engineering according to claim 1, characterized in that: Step S2 includes: A) Parametric modeling of flue, insulation layer, and geotechnical layer; B) Perform finite element meshing on the flue; C) Perform conjugate heat transfer simulation based on material parameters and boundary conditions to extract temperature data of flue, insulation layer and rock and soil layer; D) Analyze the temperature data. If the temperature difference requirements are met, the design is completed. If not, adjust the insulation layer parameters until the temperature difference requirements are met.

4. The method for suppressing thermal infrared characteristics of underground engineering according to claim 1, characterized in that: The insulation layer parameters include at least one of the insulation layer material, the insulation layer thickness and the insulation layer wrapping length.

5. The method for suppressing thermal infrared characteristics of underground engineering according to claim 4, characterized in that: The material of the heat insulation layer is selected from at least one of rock wool, foam glass, aerogel, porous ceramics, vacuum insulation board and modified polypropylene insulation board.

6. The method for suppressing thermal infrared characteristics of underground engineering according to claim 4, characterized in that: The thickness of the insulation layer is ≤100mm.

7. The method for suppressing thermal infrared characteristics of underground engineering according to claim 4, characterized in that: The insulation wrap length is consistent with the total length of the flue.

8. The method for suppressing thermal infrared characteristics of underground engineering according to claim 1, characterized in that: The thickness of the rock layer is 80-120m, the depth is 200-220m, and the depth of the external environment is 80-120m.

9. The method for suppressing thermal infrared characteristics of underground engineering according to claim 1, characterized in that: The temperature control system includes a temperature monitoring unit and a temperature regulating unit. The temperature regulating unit includes a refrigeration device and / or a heating device.

10. The method for suppressing thermal infrared characteristics of underground engineering according to claim 1, characterized in that: The outer surface of the thermal insulation layer is coated with infrared low emissivity material.

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