Gas-solid powder-based composite heat conductor, heat exchange device, preparation method and application

Abstract

The invention discloses a gas-solid powder-based composite heat conductor, a heat exchange device, a preparation method and application, and belongs to the technical field of heat transfer, and the gas-solid powder-based composite heat conductor is a packaging structure filled with high-heat-conductivity solid powder and high-heat-conductivity gas. The gas-solid powder-based composite heat conductor is divided into a bottom-layer heat conduction area, a middle-layer heat conduction area and a top-layer heat conduction area from bottom to top; the particle size of the bottom-layer heat-conducting-area high-heat-conducting solid powder is larger than that of the middle-layer heat-conducting-area high-heat-conducting solid powder; the porosity of the bottom heat conduction area is larger than the porosity of the middle heat conduction area is larger than the porosity of the top heat conduction area. According to the invention, electron-phonon-gas three-mode efficient heat transfer and intrinsically safe physical isolation can be realized, any high-temperature, high-pressure, flammable and explosive fluid is suitable for being adopted as heat-carrying fluid, and the device is suitable for heat exchange under severe working conditions of high temperature, high pressure and easy leakage reaction of a heat-transfer medium; the problem that safety and heat transfer performance of double-fluid and even multi-fluid heat exchange equipment cannot be considered at the same time under severe working conditions is solved.

Description

Technical Field

[0001] The present invention belongs to the field of heat transfer technology and relates to a heat conducting structure, in particular to a gas-solid powder-based composite heat conductor and a heat exchange device, a preparation method and an application. Background Art

[0002] In extreme industrial scenarios such as high temperature, high pressure, leakage, and severe corrosion, a safe and reliable heat transfer system is a core element to ensure the stable operation of the process. Advanced heat transfer structures can improve the energy efficiency of energy-intensive industries by 15-30%. At the same time, industrial accidents directly or indirectly related to the failure of heat transfer equipment account for a high proportion. For example, in the field of new energy, solar thermal power generation has a large-capacity heat storage and peak-shaving capacity, which can effectively alleviate the intermittent, volatile, and random defects of solar energy. It has significant advantages in grid adaptability and all-weather power generation, and is attracting much attention. However, existing solar thermal collectors have a key bottleneck: the high power and non-uniform heat flux density distribution of the concentrating system cause local overheating and bursting of the collector tubes, seriously threatening the safe operation of the system. The required high-precision concentrating equipment increases construction costs, restricting the economic feasibility and large-scale development of solar thermal power generation.

[0003] Furthermore, heat transfer structures used in demanding applications often face common challenges: balancing heat transfer efficiency and safety requirements. Leakage and contact between heat transfer media can easily lead to cross-contamination and runaway reactions. For example, in the nuclear energy industry, gas-cooled fast reactors and sodium-cooled fast reactors are plagued by leakage risks. Helium leaks and refills in gas-cooled fast reactors drive up costs, as helium, a strategic resource, is scarce globally and its supply chain is highly concentrated. In the latter, sodium metallic leaks can create unpredictable explosions. Summary of the Invention

[0004] The present invention provides a gas-solid powder-based composite heat conductor and heat exchange device, a preparation method and applications thereof, in order to overcome the defects of the prior art.

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

[0006] In a first aspect, the present invention provides a gas-solid powder-based composite thermal conductor. The gas-solid powder-based composite thermal conductor comprises a packaged structure filled with a high-thermal-conductivity solid powder and a high-thermal-conductivity gas. The high-thermal-conductivity solid powder has a thermal coefficient greater than 0.15 W / m·K, and the high-thermal-conductivity gas has a thermal coefficient greater than 300 W / m·K.

[0007] Furthermore, the gas-solid powder-based composite thermal conductor is divided into a bottom thermal conductive zone, a middle thermal conductive zone and a top thermal conductive zone from bottom to top; the particle size of the high thermal conductive solid powder in the bottom thermal conductive zone is greater than the particle size of the high thermal conductive solid powder in the middle thermal conductive zone and greater than the particle size of the high thermal conductive solid powder in the top thermal conductive zone; the porosity of the bottom thermal conductive zone is greater than the porosity of the middle thermal conductive zone and greater than the porosity of the top thermal conductive zone.

[0008] Furthermore, the particle size of the high thermal conductivity solid powder in the bottom thermal conductive zone is 150-200 μm, and the porosity of the bottom thermal conductive zone is 40-50%, preferably 45%; the particle size of the high thermal conductivity solid powder in the middle thermal conductive zone is 45-200 μm, and the porosity of the middle thermal conductive zone is 35-40%, preferably 38%; the particle size of the high thermal conductivity solid powder in the top thermal conductive zone is 20-45 μm, and the porosity of the top thermal conductive zone is 25-35%, preferably 30%.

[0009] Furthermore, the particle shape of the high thermal conductivity solid powder in the bottom thermal conductive zone is non-spherical, such as angular, flake, and rod-shaped; the particle shape of the high thermal conductivity solid powder in the middle thermal conductive zone includes spherical and non-spherical; the top thermal conductive zone is also filled with metal foam crumbs or graphene foam crumbs with a porosity greater than 90% and a thermal conductivity coefficient of 40 to 60 W / m·K, and the amount of metal foam crumbs or graphene foam crumbs added does not exceed 0.5wt%.

[0010] Furthermore, the high thermal conductivity solid powder is copper powder or graphite powder; and the high thermal conductivity gas is helium or hydrogen.

[0011] In a second aspect, the present invention further provides a heat exchange device characterized by comprising an encapsulated cavity and a heat exchange tube; the heat exchange tube passes through the encapsulated cavity, with a gap defined between the outer wall of the heat exchange tube and the inner wall of the encapsulated cavity, within which is disposed the aforementioned gas-solid powder-based composite heat conductor. Specifically, an encapsulated structure is formed between the outer wall of the heat exchange tube and the inner wall of the encapsulated cavity, the interior of which is filled with a highly thermally conductive solid powder and a highly thermally conductive gas. A heat transfer fluid is passed through the heat exchange tube, while a heat transfer medium circulates outside the encapsulated cavity.

[0012] Furthermore, the packaging cavity is a vertically arranged cylindrical cylinder; the heat exchange tube is a straight tube, which is arranged in the packaging cavity; the heat carrier fluid circulates in the heat exchange tube, and the heat transfer medium circulates outside the cylindrical cylinder of the packaging cavity; or, the packaging cavity is a vertically arranged annular cylinder; the heat exchange tube is a swirl tube, which is wound and arranged in the packaging cavity; the heat carrier fluid circulates in the heat exchange tube, and the heat transfer medium circulates inside / outside the annular cylinder of the packaging cavity, which can be used in tower-type solar thermal collectors, coke oven riser raw gas waste heat recovery and other scenarios; or, the packaging cavity is a vertically arranged rectangular plate; the heat exchange tube is a serpentine tube, which is arranged in the packaging cavity; the heat carrier fluid circulates in the heat exchange tube, and the heat transfer medium circulates on one side or both sides of the rectangular plate of the packaging cavity, which can be used in variable operating condition ship power systems, LNG gasifiers and other scenarios.

[0013] In a third aspect, the present invention also provides a preparation method for the above-mentioned heat exchange device, comprising the following steps: S1, pre-hanging the heat exchange tube in the packaging cavity and placing it in the center; S2, dividing the packaging cavity into three sections in the vertical direction as the bottom heat conduction zone, the middle heat conduction zone and the top heat conduction zone, and filling them with high thermal conductivity solid powder from bottom to top in sequence to fill the gap between the heat exchange tube and the packaging cavity; S3, after the high thermal conductivity solid powder is filled in the partitions, vacuuming the packaging cavity to remove excess air, injecting high thermal conductivity gas, and maintaining a slight negative pressure of 95 to 100 kPa.a at room temperature.

[0014] Furthermore, in S2, when filling the bottom thermal conductive area with high thermal conductive solid powder, no additional vibration is performed; when filling the middle thermal conductive area with high thermal conductive solid powder, low-frequency vibration of 15 to 30 Hz is used for compaction, and the vibration time is 10 to 30 s; the maximum filling volume fraction of the high thermal conductive solid powder in the packaging cavity is less than 0.7.

[0015] In a fourth aspect, the present invention further provides application of the above-mentioned heat exchange device in heat transfer.

[0016] The beneficial effects of the present invention are as follows: the present invention provides a gas-solid powder-based composite heat conductor and heat exchange device, preparation method, and application. The gas-solid powder-based composite heat conductor is composed of high thermal conductivity solid powder and high thermal conductivity gas, and can achieve electron-phonon-gas trimodal efficient heat transfer and intrinsically safe physical isolation. The heat carrier fluid is suitable for any high-temperature, high-pressure, flammable and explosive fluid, and is suitable for heat exchange under harsh working conditions of high temperature, high pressure, and easy leakage and reaction of heat transfer medium. It solves the problem of the inability to balance the safety and heat transfer performance of dual-fluid or even multi-fluid heat exchange equipment under harsh working conditions. The gas-solid powder-based composite heat conductor can be encapsulated between packaging cavities and heat exchange tubes of different structures to be suitable for a variety of heat transfer applications such as tower solar thermal collectors, sodium-cooled fast neutron reactors, coke oven riser raw gas waste heat recovery, variable working condition ship power systems, and LNG gasifiers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of two cylindrical heat exchange devices;

[0018] Figure 2 It is a structural schematic diagram of an annular tube heat exchange device (the packaging cavity is partially cut away);

[0019] Figure 3 It is a schematic structural diagram of a rectangular plate heat exchange device;

[0020] Figure 4 This is a schematic diagram of the heat exchange device of Example 1 applied to an ultra-high parameter solar thermal collector;

[0021] Figure 5 This is a heat transfer effect diagram of Example 1;

[0022] Figure 6 This is a schematic diagram of the heat exchange device of Example 2 applied to the recovery of waste heat from raw coal gas in a coke oven riser;

[0023] The markings in the accompanying drawings are: 1. packaging cavity; 2. heat exchange tube; 3. gas-solid powder-based composite heat conductor; 31. bottom heat conduction area; 32. middle heat conduction area; 33. top heat conduction area; A. heat carrier fluid; B. heat transfer medium. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 As shown, the present invention provides a heat exchange device, including a packaging cavity 1 and a heat exchange tube 2. The heat exchange tube 2 passes through the packaging cavity 1, and there is a gap between the outer wall of the heat exchange tube 2 and the inner wall of the packaging cavity 1, and a gas-solid powder-based composite heat conductor 3 is provided in the gap. The gas-solid powder-based composite heat conductor 3 is a packaging structure filled with high thermal conductivity solid powder and high thermal conductivity gas. High thermal conductivity solid powder is a solid powder with a guiding thermal coefficient greater than 0.15W / m·K, and high thermal conductivity gas is a gas with a guiding thermal coefficient greater than 300W / m·K. The heat exchange tube 2 is used to pass the heat carrier fluid A, and the outside of the packaging cavity 1 is used to circulate the heat transfer medium B.

[0026] From bottom to top, the gas-solid powder-based composite thermal conductor 3 is divided into a bottom thermal conductive zone 31, a middle thermal conductive zone 32, and a top thermal conductive zone 33. The particle size of the high thermal conductive solid powder in the bottom thermal conductive zone 31 is greater than that in the middle thermal conductive zone 32, and greater than that in the top thermal conductive zone 33. The porosity of the bottom thermal conductive zone 31 is greater than that of the middle thermal conductive zone 32, and greater than that of the top thermal conductive zone 33.

[0027] Specifically, the particle size of the high-thermal-conductivity solid powder in the bottom heat-conducting zone 31 is 150-200 μm, and the porosity of the bottom heat-conducting zone 31 is 40-50%, preferably 45%. The particle size of the high-thermal-conductivity solid powder in the middle heat-conducting zone 32 is 45-200 μm, and the porosity of the middle heat-conducting zone 32 is 35-40%, preferably 38%. The particle size of the high-thermal-conductivity solid powder in the top heat-conducting zone 33 is 20-45 μm, and the porosity of the top heat-conducting zone 33 is 25-35%, preferably 30%.

[0028] The high-thermal-conductivity solid powder in the bottom heat-conducting zone 31 has non-spherical shapes, such as angular, flake, or rod-shaped particles. The high-thermal-conductivity solid powder in the middle heat-conducting zone 32 has both spherical and non-spherical shapes. The top heat-conducting zone 33 is also filled with metal foam crumbs or graphene foam crumbs with a porosity greater than 90% and a thermal conductivity of 40-60 W / m·K. The amount of metal foam crumbs or graphene foam crumbs added does not exceed 0.5 wt%.

[0029] The high thermal conductivity solid powder is copper powder or graphite powder, and the high thermal conductivity gas is helium or hydrogen.

[0030] In a specific embodiment, Figure 1 As shown, the encapsulated cavity 1 is a vertically arranged cylindrical tube. The heat exchange tube 2 is a straight tube and is arranged in the encapsulated cavity 1. The heat transfer fluid A flows in the heat exchange tube 2, and the heat transfer medium B flows outside the cylindrical tube of the encapsulated cavity 1.

[0031] In another specific embodiment, Figure 2 As shown, the encapsulation cavity 1 is a vertically arranged annular cylinder. The heat exchange tube 2 is a vortex tube, which is wound and arranged in the encapsulation cavity 1. The heat-carrying fluid A circulates in the heat exchange tube 2, and the heat transfer medium B circulates in / outside the annular cylinder of the encapsulation cavity 1. It can be used in scenarios such as tower-type solar thermal collectors and coke oven riser raw gas waste heat recovery. When used in solar thermal collectors, the external heat transfer medium B is extremely active thermosiphon metal sodium, potassium, etc., which condenses on the outer wall of the annular cylinder to achieve rapid uniform heating of uneven solar energy concentration. Supercritical water, compressed air, etc. are used as heat-carrying fluid A. When used for coke oven riser raw gas waste heat recovery, the external heat transfer medium B raw gas flows through the inner wall of the annular cylinder, and some low-temperature coke adheres to the wall. The heat-carrying fluid A is circulating water, heat transfer oil, etc., which eliminates the risk of contact reaction.

[0032] In another specific embodiment, Figure 3 As shown, the encapsulation cavity 1 is a vertically arranged rectangular plate. The heat exchange tube 2 is a serpentine tube, disposed within the encapsulation cavity 1. Heat carrier fluid A flows through the heat exchange tube 2, while heat transfer medium B flows on one or both sides of the rectangular plate of the encapsulation cavity 1. This device can be used in scenarios such as variable operating conditions ship power systems and LNG vaporizers.

[0033] The preparation method of the heat exchange device of the present invention comprises the following steps:

[0034] S1. Pre-hang the heat exchange tube 2 into the packaging cavity 1 and place it in the center.

[0035] S2. The packaging cavity 1 is divided into three sections in the vertical direction as the bottom heat conduction area 31, the middle heat conduction area 32 and the top heat conduction area 33. High thermal conductivity solid powder is filled in sequence from bottom to top to fill the gap between the heat exchange tube 2 and the packaging cavity 1.

[0036] Among them, when filling the bottom thermal conductive area 31 with high thermal conductivity solid powder, bridging and interlocking phenomena occur between coarse particles of 150 to 200 μm and non-spherical shapes (angular, flake, rod-shaped, etc.), forming a large number of irregular gaps, with a target porosity of about 45% without additional vibration.

[0037] When filling the middle heat conduction zone 32 with high thermal conductivity solid powder, particles with a size of 45 to 200 μm and a mixed non-spherical and spherical shape are compacted using a low-frequency vibration of 15 to 30 Hz to ensure that the spherical particles slide into the gaps between the non-spherical particles, reducing the porosity to 38%. The vibration time is short (10 to 30 s) to prevent the particles from penetrating into the bottom layer.

[0038] When filling the top heat transfer zone 33 with a high thermal conductivity solid powder, fine particles of 20 to 45 μm are used, with a target porosity of approximately 30%. To prevent further porosity reduction caused by hexagonal close-packed or face-centered cubic particles, a trace amount of no more than 0.5 wt% of metal foam (porosity >90%, thermal conductivity of approximately 50 W / m·K) or honeycomb ceramic is added to guide airflow by utilizing its high permeability and thermal conductivity.

[0039] The non-spherical particles at the bottom layer disrupt the laminar boundary layer, while the small particles at the top increase the specific surface area. This arrangement of particles follows a permeability gradient, with high porosity and coarse particles at the bottom reducing resistance and low porosity and fine particles at the top enhancing heat transfer. This creates directional flow channels and increases natural convection intensity by 10-30%. The maximum filling volume fraction of the high thermal conductivity solid powder within the packaging cavity 1 is controlled to less than 0.7 to prevent accumulation and excessive compression of the high thermal conductivity gas space, which would weaken convective heat transfer.

[0040] After the high-thermal-conductivity solid powder is filled in the partitions, the packaging cavity 1 is evacuated to remove excess air. High-thermal-conductivity gas is then injected through the top opening. A slight negative pressure of 95 to 100 kPa is maintained at room temperature to enhance buoyancy-driven natural convection, reduce the thermal resistance at the gas-solid interface, and ensure low-pressure safety after heating. Electron-phonon-gas trimodal heat transfer ensures efficient heat exchange between heat carrier fluid A and external heat transfer medium B, keeping the temperature difference within 10°C.

[0041] After the high-thermal-conductivity gas is filled, the filling port is welded and sealed, enabling natural convection circulation within the enclosed, small cavity. This eliminates potential leaks, requires no refilling or maintenance throughout the lifecycle, and prevents oxidation of the high-thermal-conductivity solid powder. Furthermore, the high-thermal-conductivity gas physically isolates the heat transfer fluid A within the heat exchange tubes 2 from the heat transfer medium B outside the encapsulated cavity 1. Even if one leaks, the atmosphere within the fully enclosed area prevents direct contact and reaction between the two.

[0042] Example 1

[0043] like Figure 4 As shown, this embodiment provides a heat exchange device for ultra-high parameter solar thermal collectors. The gas-solid powder-based composite heat conductor 3 is encapsulated between the annular cylindrical encapsulation cavity 1 and the swirl heat exchange tube 2. The thermosiphon metal for concentrated heat collection is metallic sodium, potassium, etc. The high-power heat transfer medium B is condensed and released on the outer wall surface of the encapsulation cavity 1 (>5000W / m 2), and then transferred to the packaging cavity 1. The outer wall of the packaging cavity 1 is stamped with dotted protrusions and irregular wavy lines and wrinkles to prevent the condensate from gathering on the outer wall of the packaging cavity 1 to form a liquid film. The gas-solid powder-based composite thermal conductor 3 includes a high thermal conductivity gas (such as helium) and a high thermal conductivity solid powder (such as copper powder). The swirl state heat exchange tube 2 is placed in a fully enclosed area in an inert gas atmosphere to physically isolate the thermosiphon metal. The heat-carrying fluid A in the heat exchange tube 2 is supercritical water, compressed air, etc., which completely eliminates the risk of sodium-water / fire explosion reaction with thermosiphon metal sodium, etc., while improving the outlet temperature (up to 800°C) and the collector efficiency. The high thermal conductivity gas circulates naturally in a small, closed space, eliminating the pumping unit, valve group and connecting pipeline, and there is no dynamic sealing point. Unlike the gas-cooled reactor that needs continuous gas replenishment due to helium leakage, this structure establishes a completely independent closed-domain inflation system, and no gas replenishment maintenance is required throughout its life cycle. Finally, the density of the heat transfer medium B is optimized and distributed to the surface of the heat exchange tube 2. like Figure 5 As shown, compared with the traditional packed bed heat transfer structure, the gas-solid powder-based composite heat conductor 3 greatly improves the heat transfer efficiency while ensuring intrinsic safety.

[0044] Example 2

[0045] like Figure 6 As shown, this embodiment provides a heat exchange device for recovering waste heat from raw coal gas in a coke oven riser, and a gas-solid powder-based composite heat conductor 3 is encapsulated between an annular cylindrical encapsulation cavity 1 and a swirl-shaped heat exchange tube 2. The gas-solid powder-based composite heat conductor 3 includes filled high thermal conductivity solid powder graphite powder and filled high thermal conductivity gas hydrogen. The heat transfer medium B, raw coal gas, flows through the cylinder of the annular cylindrical encapsulation cavity 1. The coke formed after the tar vapor is cooled will only partially remain on the inner wall of the cylinder and be physically isolated from the heat exchange tube 2, thus avoiding the possibility of contact with the heat-carrying fluid A (heat transfer oil or water). It is also very convenient to clean the coke, solving the problems of medium leakage, high temperature resistance, dry burning resistance, low steam production pressure (≤0.8MPa), and low efficiency. The gas-solid powder-based composite heat conductor 3 efficiently and high-quality recovers approximately 36% of the medium-temperature waste heat (raw gas) from the coking industry, producing 5.0 MPa saturated steam, high-temperature thermal oil above 270°C, or superheated steam above 400°C. This heat recovery is ≥20% higher than existing technologies, significantly reducing waste gas emissions. This heat exchange device enables the safe circulation of heat transfer fluid A (thermal oil, water), eliminating the risk of condensation from tar vapor. It can be integrated with chemical production processes, offering a wider range of applications and higher efficiency.

[0046] In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art.

[0047] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. cited in the invention are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0048] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A gas-solid powder-based composite thermal conductor, characterized by: The gas-solid powder-based composite thermal conductor is a packaging structure filled with high thermal conductivity solid powder and high thermal conductivity gas.

2. The gas-solid powder-based composite thermal conductor according to claim 1, characterized in that: The gas-solid powder-based composite heat conductor is divided into a bottom heat conduction zone, a middle heat conduction zone and a top heat conduction zone from bottom to top; The particle size of the high thermal conductivity solid powder in the bottom thermal conductive area is greater than the particle size of the high thermal conductivity solid powder in the middle thermal conductive area and greater than the particle size of the high thermal conductivity solid powder in the top thermal conductive area; The porosity of the bottom heat conduction zone > the porosity of the middle heat conduction zone > the porosity of the top heat conduction zone.

3. The gas-solid powder-based composite thermal conductor according to claim 2, characterized in that: The particle size of the high thermal conductivity solid powder in the bottom thermal conductive area is 150 to 200 μm, and the porosity of the bottom thermal conductive area is 40 to 50%; The particle size of the high thermal conductivity solid powder in the middle thermal conductive zone is 45 to 200 μm, and the porosity of the middle thermal conductive zone is 35 to 40%; The particle size of the high thermal conductivity solid powder in the top thermal conductive area is 20 to 45 μm, and the porosity of the top thermal conductive area is 25 to 35%.

4. The gas-solid powder-based composite thermal conductor according to claim 3, characterized in that: The particle shape of the high thermal conductivity solid powder in the bottom thermal conductive area is non-spherical; The particle shapes of the high thermal conductivity solid powder in the middle thermal conductive zone include spherical and non-spherical; The top heat conducting area is further filled with metal foam crumbs or graphene foam crumbs, and the amount of metal foam or honeycomb ceramic added does not exceed 0.5 wt %.

5. The gas-solid powder-based composite thermal conductor according to claim 1, characterized in that: The high thermal conductivity solid powder is copper powder or graphite powder; The high thermal conductivity gas is helium or hydrogen.

6. A heat exchange device, characterized in that: It includes a packaging cavity and a heat exchange tube; the heat exchange tube passes through the packaging cavity, and there is a gap between the outer wall of the heat exchange tube and the inner wall of the packaging cavity, and the gas-solid powder-based composite heat conductor according to any one of claims 1 to 5 is arranged in the gap.

7. The heat exchange device according to claim 6, characterized in that: The packaging cavity is a vertically arranged cylindrical tube; the heat exchange tube is a straight tube, which is arranged in the packaging cavity; Alternatively, the packaging cavity is a vertically arranged annular cylinder; the heat exchange tube is a vortex tube, which is wound and arranged in the packaging cavity; Alternatively, the packaging cavity is a vertically arranged rectangular plate; the heat exchange tube is a serpentine tube, which is arranged in the packaging cavity.

8. The method for preparing a heat exchange device according to claim 6 or 7, wherein: The following steps are involved: S1. Pre-hanging the heat exchange tube into the packaging cavity and placing it in the center; S2. Divide the packaging cavity into three sections in the vertical direction as the bottom heat conduction area, the middle heat conduction area, and the top heat conduction area, and fill them with high thermal conductivity solid powder from bottom to top to fill the gap between the heat exchange tube and the packaging cavity; S3. After the high thermal conductivity solid powder is filled in different areas, the packaging cavity is evacuated to remove excess air, and high thermal conductivity gas is injected, and a slight negative pressure of 95 to 100 kPa.a is maintained at room temperature.

9. The method for preparing a heat exchange device according to claim 8, characterized in that: In S2, when filling the bottom heat conducting area with the high thermal conductivity solid powder, no additional compaction is performed; When filling the middle heat-conducting zone with high thermal conductivity solid powder, low-frequency vibration of 15 to 30 Hz is used for compaction, and the vibration time is 10 to 30 seconds; The maximum filling volume fraction of the high thermal conductivity solid powder in the packaging cavity is less than 0.

7.

10. Use of the heat exchange device according to claim 6 or 7 in heat transfer.

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