A heat pipe dredging coupling active sweating cooling self-adaptive heatproof structure

Abstract

The present application relates to a kind of heat pipe dredging coupling active perspiration cooling self-adapting heat protection structure, wherein: active cooling perspiration porous structure and heat pipe type dredging heat protection structure are mechanically connected, heat pipe type dredging heat protection structure cavity is embedded with working medium storage structure unit;Under the condition of pneumatic heating, heat pipe type dredging heat protection structure will the heat of outer wall surface pneumatic heating be evenly transported to inner wall surface, and the heat of inner wall surface of heat pipe type dredging heat protection structure is transferred to inside by high thermal conductivity medium by working medium storage structure unit, promote the evaporation phase change of liquid working medium stored in inside, and working medium gas is injected to the boundary layer of heat protection structure by active cooling perspiration porous structure;When the heating of pneumatic heating action weakens, the heat transmission of heat pipe type dredging heat protection structure is not enough to trigger the phase change of stored liquid working medium, and the injection action of working medium gas in active cooling perspiration porous structure stops;Such cyclic action, realize the self-adapting heat protection of stagnation point porous perspiration and heat pipe type dredging heat protection structure heat dredging.

Description

Technical Field

[0001] This invention belongs to the technical field of aerodynamic thermal protection systems in aerospace engineering, and provides a heat pipe-guided coupling active sweating cooling adaptive thermal protection structure. Background Technology

[0002] When high-speed aerospace vehicles fly through the Earth's atmosphere, the intense collisions and friction between their high-speed solid surfaces and atmospheric gas molecules cause a rapid increase in gas temperature. This heat is continuously transferred to the vehicle's surface, generating aerodynamic heating. To prevent the high temperatures caused by aerodynamic heating from damaging the vehicle's structural safety, specialized materials or structures are typically designed on the vehicle's surface to control the impact of surface heat transfer, thus ensuring the safety of the vehicle's internal structure. This is also known as a spacecraft thermal protection system. Spacecraft thermal protection systems typically employ active cooling structures that induce sweating and heat pipe-guided thermal protection structures.

[0003] The active cooling thermal protection structure uses an active supply system to spray the working fluid stored inside the aircraft through a porous structure under pressure to reduce the temperature of the thermal protection structure and form a boundary layer thermal blockage effect to reduce aerodynamic heating. This thermal protection method has high cooling efficiency, but in actual use, it requires a working fluid supply system, which has a large system compensation, and the system is complex and difficult to control the working fluid supply, thus limiting its application.

[0004] The heat pipe-guided thermal protection structure is based on the principle of heat pipe operation, integrally molding the thermal protection component into a vacuum-sealed cavity structure with an embedded capillary wick structure, working fluid, and reinforcing structure. Under pneumatic heating, the condensed working fluid inside the thermal protection structure undergoes a phase change, and the vapor structure circulates within the sealed cavity. In lower-temperature areas, the working fluid liquefies and condenses, and under the combined action of the capillary wick structure and vapor pressure, the liquid working fluid is transported to higher-temperature areas, where it undergoes another phase change upon heating. The working fluid, through the "gas phase change - gas vapor movement - liquefaction and condensation - capillary transport - gas phase change" cycle within the sealed cavity via the capillary wick structure, achieves rapid heat transfer within the thermal protection structure. This thermal protection structure is compact, requires no additional working fluid supply system, and can achieve adaptive heat balance within a certain pneumatic heating environment. However, limited by the operating temperature of the thermal protection structure shell and the physical limits of working fluid transport within the cavity, the adaptability of this thermal protection method to pneumatic heating heat flux density is weak. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a heat pipe-guided coupling active sweating cooling adaptive heat protection structure, which realizes adaptive heat protection by stagnant point porous sweating and heat pipe-type guided heat protection structure.

[0006] The solution of the present invention is: a heat pipe coupled active cooling adaptive heat protection structure, which includes an active cooling sweating porous structure, a heat pipe heat protection structure, and a working fluid storage structure unit; the active cooling sweating porous structure and the heat pipe heat protection structure are mechanically connected, and the working fluid storage structure unit is embedded inside the cavity of the heat pipe heat protection structure.

[0007] Under pneumatic heating conditions, the heat pipe-type heat-resistant structure uniformly transports the heat from the outer wall to the inner wall. The working fluid storage unit rapidly transfers the heat from the inner wall of the heat pipe-type heat-resistant structure to the interior via a highly thermally conductive medium, further acting as a heat source to promote the evaporation and phase change of the stored liquid working fluid. The working fluid gas is then injected into the boundary layer of the heat-resistant structure through the porous structure in the active cooling and sweating porous structure, realizing the heat-resistant process of the active sweating and cooling mechanism. When the pneumatic heating effect weakens, the heat transferred by the heat pipe-type heat-resistant structure is insufficient to trigger the phase change of the stored liquid working fluid, and the injection of the working fluid gas in the active cooling and sweating porous structure stops. This cycle continues, achieving adaptive heat-resistant design through stagnation point porous sweating and heat conduction by the heat pipe-type heat-resistant structure.

[0008] Preferably, the maximum pore size in the active cooling and sweating porous structure is not greater than 0.2 mm and the porosity is not less than 30%.

[0009] Preferably, the forming process of the active cooling and sweating porous structure is: porous body sintering, stacking of wire meshes with different mesh counts, microstructure additive manufacturing, and template method CVD or PVD deposition.

[0010] Preferably, the heat pipe-type heat-insulating structure includes an encapsulated end cap, a working fluid channel, a vacuum chamber, a capillary wick structure, and an outer shell.

[0011] The outer shell is a double-layer hollow structure. The encapsulation end cap is sealed to the outer shell, encapsulating the double-layer hollow structure into a vacuum cavity. The vacuum cavity is filled with working fluid. The working fluid flow channels are evenly arranged on the inner wall of the vacuum cavity to promote the working fluid to flow back from the working fluid condensation area to the working fluid evaporation phase change area. The capillary wick structure is used for working fluid vapor condensation, adsorption and reflux.

[0012] After the heat pipe-type heat-insulating structure is aerodynamically heated on the outer wall, it starts to activate. Different regions within the vacuum chamber experience working fluid evaporation phase change, steam flow, and steam condensation. In the working fluid condensation region, the gaseous working fluid condenses in the capillary wick structure. Under the combined action of capillary force and gas pressure, the condensed working fluid is transported from the working fluid condensation region to the working fluid evaporation phase change region through the working fluid flow channel. After being transported to the working fluid evaporation phase change region, it evaporates into a gaseous working fluid. This cycle repeats, uniformly transporting the aerodynamic heating heat from the outer wall to the inner wall.

[0013] Preferably, the cross-section of the working fluid channel is circular, rectangular, "D" shaped, or "Ω" shaped.

[0014] Preferably, the maximum geometric dimension of the working fluid channel is less than 0.5 mm.

[0015] Preferably, the maximum void size of the capillary core structure is not greater than 0.2 mm and the porosity is not less than 30%.

[0016] Preferably, the material of the outer shell is: copper-based alloy, iron-based alloy, nickel-based high-temperature alloy, niobium-based high-temperature alloy, molybdenum-based high-temperature alloy, tantalum-based high-temperature alloy, tungsten-based high-temperature alloy, C / C composite material, C / SiC composite material, SiC / SiC composite material, or ultra-high temperature ceramic composite material.

[0017] Preferably, the working fluid storage unit structure includes a second encapsulation cap, an outer structural shell, and a thermally conductive medium;

[0018] The outer shell has a hollow cavity structure, which serves as a working fluid storage area to store the working fluid used for sweating and cooling.

[0019] The second encapsulation cap is sealed together with the outer shell at room temperature, making the working fluid storage area a closed area; it self-destructs under high temperature, providing an outlet for the working fluid storage area. This outlet is connected to the active cooling and sweating porous structure, allowing the working fluid to overflow from the outlet and dissipate heat through the active cooling and sweating porous structure.

[0020] A heat-conducting medium is filled in the working fluid storage area to increase the heating area of ​​the working fluid and to quickly export the working fluid to the outlet of the working fluid storage area.

[0021] Preferably, the heat-conducting medium is a fiber bundle formed by a directional array.

[0022] The advantages of this invention compared to the prior art are:

[0023] (1) The heat protection structure of the present invention, compared with the typical active sweating cooling technology, eliminates the complex working fluid supply system, has lower system compensation, can achieve thermally adaptive sweating cooling performance, avoids complex control process, and has higher reliability and engineering application feasibility; compared with the typical ventilated heat protection structure, it has a higher aerodynamic heating heat flux density adaptability, can cope with the extreme thermal environment of aerodynamic heating with higher heat flux density, and can be applied to areas with extremely high peak aerodynamic heating heat flux density and extremely uneven heat flow distribution, such as the nose cone and leading edge of aircraft, the leading edge of engine air intake, overflow port and fuel injection support plate.

[0024] (2) The main principle of this invention is to use a porous structure in the stagnation area to achieve active sweating and cooling, and a heat pipe-type heat-conducting protective structure in the large area. Simultaneously, a high thermal conductivity working fluid and a liquid working fluid storage unit are embedded inside the heat-conducting protective structure cavity. Under the action of incoming airflow heating, the heat pipe-type heat-conducting protective structure induces a phase change in the stored liquid working fluid via the high thermal conductivity structure, and the heat is then guided to the boundary layer through the stagnation porous structure, further reducing the airflow heating effect. When the incoming airflow heating weakens, the heat transferred by the heat pipe-type heat-conducting protective structure is insufficient to trigger a phase change in the stored liquid working fluid, and the gas entrainment effect of the working fluid in the stagnation porous area stops. This cyclical action achieves adaptive heat protection through stagnation porous sweating and heat conduction by the heat pipe-type heat-conducting protective structure.

[0025] (3) The fiber bundle of the present invention has a designable directional high thermal conductivity according to the fiber orientation to meet the needs of rapid heat transfer; at the same time, the fiber bundle has a non-uniform arrangement density, forming a non-uniform porosity distribution, with higher porosity at the center to achieve a larger working fluid storage capacity, and lower porosity at the location far from the center to achieve higher capillary driving force and more effective working fluid flow control. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the heat pipe-type conductive coupling sweating active cooling adaptive conductive heat protection structure according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the heat pipe-type conductive coupling sweating active cooling adaptive conductive heat protection cross-sectional structure according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the active cooling and sweating porous structure according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the cross-sectional structure of the cone-shaped heat pipe-type heat-resistant structure according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic cross-sectional view of the high porosity and high thermal conductivity working fluid storage unit structure according to an embodiment of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the embodiments.

[0032] This invention provides a heat pipe coupled active cooling adaptive heat shield structure. Taking the nose cone heat shield structure commonly found in aerospace vehicles as an example, the encapsulated heat pipe coupled active evaporative cooling adaptive heat shield structure consists of two parts, such as... Figure 1As shown, the end cap is an active cooling and sweating porous structure 1, and the heat pipe-type heat-insulating structure 2 is a large-area heat-dissipating structure. The active cooling and sweating porous structure 1 and the heat pipe-type heat-dissipating structure 2 can be mechanically connected by threads, flanges, or by welding.

[0033] Figure 2 A schematic diagram of a heat pipe-coupled active transpiration cooling adaptive thermal protection structure is presented, which consists of three independent structural units: an active cooling transpiration porous structure 1, a heat pipe-type transpiration thermal protection structure 2, and a working fluid storage structure unit 3. The active cooling transpiration porous structure 1 and the heat pipe-type transpiration thermal protection structure 2 are mechanically connected, with the working fluid storage structure unit 3 embedded inside the cavity of the heat pipe-type transpiration thermal protection structure 2. Under pneumatic heating conditions, the working fluid storage structure unit 3 is connected to the active cooling transpiration porous structure 1. The connection between the heat pipe-type transpiration thermal protection structure 2 and the high-porosity, high-thermal-conductivity working fluid storage structure unit 3 needs to minimize contact thermal resistance, which can be achieved through high-precision mechanical connections, brazing with filler metal at the contact surface, or other connection methods that reduce thermal resistance.

[0034] Under pneumatic heating conditions, the heat pipe-type heat-resistant structure 2 in the region with relatively mild heat flux density uniformly transports the pneumatically heated heat from the outer wall to the inner wall. The working fluid storage structure unit 3 rapidly transfers the heat from the inner wall of the heat pipe-type heat-resistant structure 2 to the interior via a highly thermally conductive medium, further acting as a heat source to promote the evaporation and phase change of the stored liquid working fluid. The working fluid gas is then injected into the boundary layer of the heat-resistant structure through the porous structure in the active cooling and sweating porous structure 1, where it dissipates heat through active sweating and cooling. When the pneumatic heating effect weakens, the heat transferred by the heat pipe-type heat-resistant structure 2 is insufficient to trigger the phase change of the stored liquid working fluid, and the injection of the working fluid gas in the active cooling and sweating porous structure 1 stops. This cyclical action enables adaptive heat protection through stagnation point porous sweating and heat conduction by the heat pipe-type heat-resistant structure.

[0035] Figure 3 This is a cross-sectional schematic diagram of the active cooling nasal cone structure. The main function of the active cooling and sweating porous structure 1 is to provide a porous channel for sweating and cooling. It is made of materials with high temperature resistance. The materials of the active cooling and sweating porous structure 1 can be copper-based alloys, iron-based alloys, nickel-based high-temperature alloys, niobium-based high-temperature alloys, molybdenum-based high-temperature alloys, tantalum-based high-temperature alloys, tungsten-based high-temperature alloys, C / C composite materials, C / SiC composite materials, SiC / SiC composite materials, and ultra-high temperature ceramic composites (UHTCs). The pore structure can be ordered or pore-free. Generally, the maximum pore size is required to be no greater than 0.2 mm and the porosity is no less than 30%. The forming process can be porous body sintering, wire mesh stacking with different mesh sizes, microstructure additive manufacturing, template method CVD or PVD deposition, etc.

[0036] Figure 4The diagram shows a detailed composition of the heat pipe-type heat-insulating structure 2, which includes an encapsulation cap 2-1, a working fluid channel 2-2, a vacuum chamber 2-3, a capillary wick structure 2-4, and an outer shell 2-5.

[0037] The outer shell 2-5 is a double-layer hollow structure. The encapsulation cap 2-1 is a heat pipe encapsulation structure, which is sealed and connected to the outer shell 2-5 to encapsulate the double-layer hollow structure into a vacuum chamber 2-3. The vacuum chamber 2-3 is filled with working fluid. The working fluid flow channel 2-2 is evenly arranged on the inner wall of the vacuum chamber 2-3 to promote the return of the working fluid from the working fluid condensation area to the working fluid evaporation phase change area. The capillary wick structure 2-4 is used for the condensation, adsorption and return of working fluid vapor.

[0038] After the heat pipe-type heat-resistant structure 2 is aerodynamically heated on the outer wall, it starts to activate. Different regions in the vacuum chamber 2-3 experience working fluid evaporation phase change, steam flow, and steam condensation. In the working fluid condensation region, the gaseous working fluid condenses in the capillary core structure 2-4. Under the combined action of capillary force and gas pressure, the condensed working fluid is transported from the working fluid condensation region to the working fluid evaporation phase change region through the working fluid flow channel 2-2. After being transported to the working fluid evaporation phase change region, it evaporates into a gaseous working fluid. This cycle repeats, uniformly transporting the aerodynamic heating heat from the outer wall to the inner wall.

[0039] Preferably, in a high vacuum environment (generally requiring a vacuum level better than 10), -4 After filling the vacuum cavity 2-3 of the heat pipe-type heat-resistant structure with an appropriate working fluid, it is welded or plastically deformed and sealed. The sealing cap 2-1 is made of the same material as the outer shell 2-5.

[0040] Preferably, the main considerations for the working fluid flow channel 2-2 are to improve the capillary force of the working fluid adsorption and reduce the flow resistance of the working fluid returning to the heating section, and its cross-section is circular, rectangular, "D" shaped or "Ω" shaped.

[0041] To ensure good capillary force, the maximum geometric dimension of the working fluid channel 2-2 is less than 0.5 mm.

[0042] The vacuum chamber 2-3 inside the heat pipe-type heat-insulating structure is filled with a working fluid, which can be appropriately selected according to the operating temperature of the heat-insulating structure. The temperature can be selected from high to low, such as thermally conductive metals, molten salts, alkali metals, alkaline earth metals, base metals, heavy metals, precious metals, rare metals, etc.

[0043] Preferably, the capillary wick structure 2-4 is a specially designed porous capillary structure that improves the condensation, adsorption and reflux design of the working fluid vapor. The material can be: copper-based alloy, iron-based alloy, nickel-based high-temperature alloy, niobium-based high-temperature alloy, molybdenum-based high-temperature alloy, niobium-based high-temperature alloy, C / C composite material, C / SiC composite material, SiC / SiC composite material or ultra-high temperature ceramic composite material.

[0044] Preferably, the maximum void size of the capillary core structure 2-4 is not greater than 0.2 mm and the porosity is not less than 30%.

[0045] Preferably, the forming process of the capillary core structure 2-4 is porous body sintering, wire mesh stacking with different mesh counts, microstructure additive manufacturing, and mold CVD or PVD deposition.

[0046] Preferably, the material of the outer shell 2-5 is: copper-based alloy, iron-based alloy, nickel-based high-temperature alloy, niobium-based high-temperature alloy, molybdenum-based high-temperature alloy, tantalum-based high-temperature alloy, tungsten-based high-temperature alloy, C / C composite material, C / SiC composite material, SiC / SiC composite material, or ultra-high temperature ceramic composite material.

[0047] Figure 4 A detailed schematic diagram of the high porosity and high thermal conductivity working fluid storage unit structure 3 is shown. The working fluid storage unit structure 3 includes a second encapsulation cap 3-1, an outer structural shell 3-2, and a thermally conductive medium 3-2.

[0048] The outer shell 3-2 has a hollow structure inside, which serves as the working fluid storage area 3-4 to store the working fluid used for sweating and cooling.

[0049] The second encapsulation cap 3-1 is encapsulated together with the outer shell 3-2 at room temperature, making the working fluid storage area 3-4 a closed area; it self-destructs under high temperature, providing an outlet for the working fluid storage area 3-4. This outlet is connected to the active cooling sweating porous structure 1, which facilitates the overflow of the working fluid from the outlet and the sweating heat dissipation through the active cooling sweating porous structure 1.

[0050] The heat-conducting medium 3-3 is filled in the working fluid storage area 3-4 to increase the heating area of ​​the working fluid and quickly export the working fluid to the outlet of the working fluid storage area 3-4.

[0051] The encapsulation cap 3-1 should preferably be made of a material that can seal at room temperature and is prone to self-destruction at high temperatures, ensuring that the working fluid can quickly escape from the encapsulation structure under high temperatures. Common materials available include various thermoplastic polymers with low melting or flow points, such as PE, PA, PP, and PVC. The outer shell 3-2 can be made of metals, non-metals, or other composite materials with high thermal conductivity, such as aluminum, copper, aluminum alloys, copper alloys, high thermal conductivity graphene composites, and high thermal conductivity carbon fiber composites. The high thermal conductivity medium 3-3 is a type of high specific surface area and high thermal conductivity material chosen to increase the heating area of ​​the working fluid without excessively occupying the effective volume within the cavity. It is typically prepared by directional arraying of fibers with high thermal conductivity, such as... Figure 5As shown. Commonly used materials available include high thermal conductivity carbon fiber, fine aluminum wire, fine copper wire, and graphene composite high thermal conductivity fibers. The fiber bundles possess designable directional high thermal conductivity based on fiber orientation, meeting the requirements for rapid heat transfer. Simultaneously, the fiber bundles have a non-uniform arrangement density, forming a non-uniform porosity distribution. Higher porosity at the center allows for greater working fluid storage, while lower porosity further away from the center enables higher capillary drive and more effective working fluid flow control. Working fluid storage areas 3-4 are used to store the working fluid for sweating and cooling; commonly used working fluids include water, ethanol, acetone, ethylene glycol, and glycerol.

[0052] The working process of the heat pipe-type conductive coupling sweating active cooling adaptive conductive heat protection structure is as follows: Under pneumatic heating conditions, the heat pipe-type conductive heat protection structure 2 in the region with relatively mild heat flux density transfers heat through the highly conductive medium in the high-porosity, high-thermal-conductivity working fluid storage structure unit 3, causing a phase change in the stored liquid working fluid. The working fluid gas is then guided to the boundary layer through the porous structure in the active cooling sweating porous structure 1. This not only directly reduces the heat transfer efficiency of the active cooling sweating porous structure 1 but also further reduces the pneumatic heating effect in the most severely affected area of ​​the pneumatic heating environment. When the incoming pneumatic heating effect weakens, the heat transferred by the heat pipe-type conductive heat protection structure 2 is insufficient to trigger a phase change in the stored liquid working fluid, and the working fluid gas entrainment effect within the active cooling sweating porous structure 1 ceases. This cyclical action achieves adaptive heat protection through stagnation point porous sweating and heat pipe-type conductive heat protection structure heat dissipation.

[0053] The heat pipe-type conductive coupling sweating active cooling adaptive conductive heat protection structure realizes that the heat from pneumatic heating is used as the active cooling working fluid to drive the heat source. This not only improves the pneumatic heating tolerance of the heat pipe-type conductive heat protection structure, but also overcomes the working fluid supply system required for the sweating cooling active heat protection structure, thereby improving the overall operating efficiency and reliability of the thermal protection system.

[0054] Example:

[0055] This embodiment takes the SR10, with a semi-cone angle of 7° and a height of 100mm as an example to design and fabricate a heat pipe-type conductive coupling sweating active cooling adaptive conductive heat protection structure.

[0056] The active cooling and sweating porous structure 1 is made of nickel-based high-temperature alloy, grade GH4169, and is formed by SLM laser printing. The lattice structure unit cell is a simple cubic (SC) + body-centered (BCC) structure with a lattice constant of 0.7 mm, a lattice connecting rod diameter of 0.2 mm, a nominal pore size of 0.25 mm, and a nominal porosity of 43%.

[0057] The heat pipe-type heat-resistant structure encapsulation cap 2-1 is made of nickel-based high-temperature alloy, grade GH4169.

[0058] The outer shell of the heat pipe-type heat-dissipating and heat-insulating structure (2-5) is made of nickel-based high-temperature alloy, grade GH4169.

[0059] The working fluid flow channel 2-2 in the heat pipe type heat pipe heat-insulating structure adopts an "Ω" shaped channel design, in which the diameter of the "Ω" shaped flow channel is 0.4mm and the column height is 0.2mm.

[0060] The working medium in the vacuum chamber 2-3 of the heat pipe-type heat-insulating structure is selected as NaK alloy with an alloy mass ratio of 0.5:0.5. The working medium is filled in a vacuum environment, and the vacuum degree is controlled to be better than 10-4 Pa during filling.

[0061] The capillary core structure 2-4 of the heat pipe-type heat-conducting and heat-insulating structure is selected as a nickel-based high-temperature alloy, grade GH4169, and adopts a spherical powder sintered capillary core with a nominal pore size of 0.15mm and a nominal porosity of 52%.

[0062] In the high-porosity, high-thermal-conductivity working fluid storage unit structure 3, the encapsulation end cap 3-1 is made of PP plastic and encapsulated by high-temperature welding; the outer shell 3-2 can be made of copper with a wall thickness of 0.5mm; the high thermal conductivity medium 3-3 is made of pure copper wire array with a diameter of 0.1mm, and the copper wire accounts for 50% of the total volume in the working fluid storage area 3-4; the working fluid storage area 3-4 is filled with deionized water working fluid.

[0063] Figure 4 The diagram shows the detailed structure of the high-porosity, high-thermal-conductivity working fluid storage unit 3, which consists of a packaging cap 3-1, an outer structural shell 3-2, a high-thermal-conductivity medium 3-2, and a working fluid storage area 3-4.

[0064] The active cooling and sweating porous structure 1 and the heat pipe-type heat-insulating structure 2 are connected by electron beam welding; the heat pipe-type heat-insulating structure 2 and the high porosity and high thermal conductivity working fluid storage structure unit 3 are coated with tin-based brazing filler metal of grade HL600 on the connecting cone surface, brazed at 190℃, and the thickness of the welding filler is not greater than 0.2mm.

[0065] After encapsulation, the heat pipe-type conductive coupling sweating active cooling adaptive conductive heat protection structure was tested in a wind tunnel under conditions of 800kW / m². 2 (Heat flux density), the heat pipe-type heat-resistant structure 2 works smoothly, and the high-porosity, high-thermal-conductivity working fluid storage structure unit 3 works normally at 800kW / m 2 After 30 seconds of pneumatic heating based on heat flux density, the working fluid is successfully discharged. The temperature of the active cooling and sweating porous structure 1 drops to 600℃. The entire system continues to work for 300 seconds without structural damage.

[0066] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A heat pipe-guided coupling active sweating cooling adaptive heat protection structure, characterized in that... It includes an active cooling and sweating porous structure (1), a heat pipe-type heat-resistant structure (2), and a working fluid storage structure unit (3); the active cooling and sweating porous structure (1) and the heat pipe-type heat-resistant structure (2) are mechanically connected, and the working fluid storage structure unit (3) is embedded inside the cavity of the heat pipe-type heat-resistant structure (2); Under pneumatic heating conditions, the heat pipe-type heat-resistant structure (2) uniformly transports the pneumatic heating heat from the outer wall surface to the inner wall surface. The working fluid storage structure unit (3) rapidly transfers the heat from the inner wall surface of the heat pipe-type heat-resistant structure (2) to the interior via a highly thermally conductive medium, further serving as a heat source to promote the evaporation and phase change of the internally stored liquid working fluid. The working fluid gas is injected into the boundary layer of the heat-resistant structure through the porous structure in the active cooling and sweating porous structure (1), realizing the heat-resistant process of the active sweating and cooling mechanism. When the pneumatic heating effect weakens, the heat transferred by the heat pipe-type heat-resistant structure (2) is insufficient to trigger the phase change of the stored liquid working fluid, and the injection of the working fluid gas in the active cooling and sweating porous structure (1) stops. This cycle is repeated to achieve adaptive heat-resistant design of stagnation point porous sweating and heat pipe-type heat-resistant structure heat conduction.

2. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 1, characterized in that... The maximum pore size of the active cooling and sweating porous structure (1) is no greater than 0.2 mm and the porosity is no less than 30%.

3. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 1, characterized in that... The forming process of the active cooling and sweating porous structure (1) is as follows: porous body sintering, wire mesh stacking with different mesh counts, microstructure additive manufacturing, template method CVD or PVD deposition.

4. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 1, characterized in that... The heat pipe-type heat-insulating structure (2) includes an encapsulation end cap (2-1), a working fluid channel (2-2), a vacuum chamber (2-3), a capillary wick structure (2-4), and an outer shell (2-5); The outer shell (2-5) is a double-layer hollow structure. The encapsulation end cap (2-1) is sealed and connected to the outer shell (2-5), encapsulating the double-layer hollow structure into a vacuum cavity (2-3). The vacuum cavity (2-3) is filled with working fluid. The working fluid flow channel (2-2) is evenly arranged on the inner wall of the vacuum cavity (2-3) to promote the working fluid to flow back from the working fluid condensation area to the working fluid evaporation phase change area. The capillary wick structure (2-4) is used for working fluid vapor condensation, adsorption and reflux. After the heat pipe-type heat-resistant structure (2) is heated by aerodynamics on the outer wall, it starts to start. Different regions in the vacuum cavity (2-3) experience working fluid evaporation phase change, steam flow, and steam condensation. In the working fluid condensation region, the gaseous working fluid condenses in the capillary core structure (2-4). Under the combined action of capillary force and gas pressure, the condensed working fluid is transported from the working fluid condensation region to the working fluid evaporation phase change region through the working fluid flow channel (2-2). After being transported to the working fluid evaporation phase change region, the evaporation phase changes into gaseous working fluid. This cycle repeats, and the aerodynamic heating heat of the outer wall is evenly transported to the inner wall.

5. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 4, characterized in that... The cross-section of the working fluid channel (2-2) is circular, rectangular, "D" shaped, or "Ω" shaped.

6. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 4, characterized in that... The maximum geometric dimension of the working fluid channel (2-2) is less than 0.5 mm.

7. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 4, characterized in that... The maximum void size of the capillary core structure (2-4) is not greater than 0.2 mm and the porosity is not less than 30%.

8. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 4, characterized in that... The outer shell (2-5) is made of the following materials: copper-based alloy, iron-based alloy, nickel-based high-temperature alloy, niobium-based high-temperature alloy, molybdenum-based high-temperature alloy, tantalum-based high-temperature alloy, tungsten-based high-temperature alloy, C / C composite material, C / SiC composite material, SiC / SiC composite material, or ultra-high temperature ceramic composite material.

9. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 1, characterized in that... The working fluid storage structure unit (3) includes a second encapsulation cap (3-1), an outer structural shell (3-2), and a thermally conductive medium (3-3); The outer shell (3-2) has a hollow structure inside, which serves as a working fluid storage area (3-4) to store the working fluid used for sweating and cooling. The second encapsulation cap (3-1) is encapsulated together with the outer shell (3-2) at room temperature, making the working fluid storage area (3-4) a closed area; it self-destructs under high temperature, providing an outlet for the working fluid storage area (3-4), which is connected to the active cooling sweating porous structure (1), so that the working fluid can overflow from the outlet and dissipate heat through sweating by the active cooling sweating porous structure (1); The heat-conducting medium (3-3) is filled in the working fluid storage area (3-4) to increase the heating area of ​​the working fluid and quickly export the working fluid to the outlet of the working fluid storage area (3-4).

10. The heat pipe conductive coupling active sweating cooling adaptive heat protection structure according to claim 9, characterized in that... The thermally conductive medium (3-3) is a fiber bundle formed by a directional array.

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