A preparation method of a C / C composite active cooling system based on forced sweating technology

Abstract

The application discloses a preparation method of a C / C composite active cooling system based on a forced sweating technology, and aims at solving problems of low reliability and low cooling efficiency of inorganic non-metallic base active cooling structure.The preparation method comprises the following steps: first, high densification of C / C composite material is realized by using a densification process; second, the densified C / C composite material is fixed on a workbench of an electric spark high-speed perforating machine; third, high energy generated by pulse power discharge is used to process micro channels on the C / C composite material; fourth, the micro channel array is processed; fifth, the C / C composite active cooling workpiece and the metal active cooling die are assembled; and sixth, a cooling working medium is filled into the C / C composite active cooling assembly through a pumping device.In the application, the method of first densification and then construction of the cooling micro channels can guarantee the mechanical properties of the material, and meanwhile, the size and distribution of the micro structure can be quantitatively designed and constructed on demand, so that the type of the cooling working medium is widened, and the heatproof efficiency is remarkably improved.

Description

Technical Field

[0001] This invention relates to a method for preparing an active cooling system for C / C composite materials. Background Technology

[0002] Future high-speed aerospace vehicles will continue to evolve towards higher Mach numbers, longer service lives, and reusability. These extremely demanding service environments pose significant challenges to the temperature resistance of critical heat-resistant components. Research indicates that the temperatures of sharp parts such as the leading edge of future high-speed aerospace vehicles are expected to exceed 5000℃, far exceeding the temperature limits of existing heat-resistant materials such as nickel-based superalloys, refractory metals and their alloys, C / SiC composites, oxidation-modified C / SiC and C / C composites, ultra-high temperature ceramic matrix composites, and C / C composites.

[0003] Improving the temperature resistance limit of materials requires addressing their thermal protection mechanisms. After decades of research, scientists have categorized thermal protection materials into three types: passive thermal protection, a combination of active and passive thermal protection, and primarily active thermal protection. Passive thermal protection mechanisms mainly include heat sink and radiation types. Heat sink mechanisms utilize the material's high specific heat capacity to absorb large amounts of heat, primarily including copper, refractory metals, and their alloys. However, metallic materials have high density and limited specific heat capacity, thus limiting their applicability to aerodynamic thermal environments and making them unsuitable for future development needs. Radiation mechanisms utilize the material's high emissivity to rapidly radiate heat to the outside world, primarily including white oxide ceramics and their composites, C / SiC composites, oxidation-modified C / SiC and C / C composites, and ultra-high temperature ceramic matrix composites. Oxide ceramics are white and have a high melting point, allowing them to be used in high-temperature environments. After oxidation, C / SiC composites, oxidation-modified C / SiC and C / C composites, and ultra-high temperature ceramic matrix composites can form a sticky, yellowish-white ceramic oxide film on their surface. This film can prevent further erosion of the material by the oxidizing atmosphere and radiate heat to the outside, allowing them to be used at higher service temperatures. For example, C / SiC and ultra-high temperature ceramic matrix composites can be stably used at high temperatures of 1600℃ and 2500℃, respectively. With researchers' continuous exploration of elements and their compounds, it is difficult to develop heat-resistant materials with a temperature resistance limit above 3000℃. The development of heat-resistant materials based on passive heat protection mechanisms faces significant technical challenges. Active / passive combined heat protection methods mainly include ablation-type heat protection and conductive heat protection. Ablation-type heat protection utilizes the material's own vaporization and sublimation physical and chemical phenomena to absorb a large amount of aerodynamic heat. This mainly includes C / C composites, carbon / phenolic composites, and silicon / phenolic composites. These materials are widely used in the nose cones of strategic aircraft and the heat-resistant bases of manned aircraft, and can be used in environments above 3000℃, but they lack the ability to be reused multiple times. Thermal conductivity-based heat protection utilizes materials or structures with high thermal conductivity to achieve rapid heat transfer from a high-temperature end to a low-temperature end. This primarily includes high thermal conductivity C / C composite materials, diamond and its composites, and high-temperature heat pipe materials. However, the thermal conductivity of high thermal conductivity C / C composite materials decreases significantly with increasing temperature, thus limiting their thermal conductivity. High-temperature heat pipe structures typically use lithium metal as the cooling medium and high-temperature alloys as the outer shell material, making them unsuitable for extremely high temperatures. In the future, developing new materials and structures relying solely on these two heat protection methods will be challenging; alternative heat protection methods are needed to significantly improve the temperature resistance limits of heat protection materials.

[0004] Active thermal protection is a method that utilizes a second-phase cooling medium to absorb aerodynamic heat or push it away from the material surface. Theoretically, this method can significantly improve the temperature resistance of materials and has become a key area of ​​focus in recent years. Research on metallic material structures based on active thermal protection technology is extensive and in-depth, including particle-sintered metallic materials, metal laminates, and 3D-printed metallic materials. However, metallic materials have low melting points; once local temperatures exceed the melting point, it can lead to blockage of cooling channels and induce component failure. Inorganic non-metallic matrix composites possess excellent temperature resistance and are one of the key materials that should be considered for active thermal protection. However, research on active cooling structures for inorganic non-metallic matrix composites is limited. This is because composites composed of carbon fibers and inorganic non-metallic matrices cannot be microstructured through particle sintering and additive manufacturing like metallic materials, limiting the application of active cooling technology for this type of material. Currently, the preparation of active cooling structures for inorganic non-metallic matrix composites mainly involves controlling the impregnation efficiency of the matrix precursor and artificially creating openings, such as porous C / SiC composites and porous C / C composites with controlled precursor impregnation pyrolysis processes. However, composite materials that are not highly densified have weak mechanical properties, and the size and distribution of cooling channels cannot be precisely designed and controlled, which leads to poor reliability and low efficiency of active cooling structures. Summary of the Invention

[0005] The purpose of this invention is to address the significant technical challenge that the temperature resistance limits of existing inorganic non-metallic matrix composites cannot meet the future requirements of aircraft. It aims to solve the problems of low reliability and cooling efficiency of inorganic non-metallic matrix active cooling structures. The invention provides a C / C composite active cooling system based on forced sweating technology, which achieves efficient densification of C / C composite materials, in-situ construction of microstructures through electrical spark digital pulse discharge, and on-demand supply of liquid or gas phase cooling working fluid.

[0006] The preparation method of the C / C composite active cooling system based on forced sweating technology of the present invention is carried out according to the following steps:

[0007] I. The C / C composite material is highly densified by a densification process, and the porosity of the densified C / C composite material is 4-7 vol.%.

[0008] 2. Fix the densified C / C composite material onto the worktable of the high-speed EDM drilling machine;

[0009] 3. An electrode tube and a guide are assembled on an EDM high-speed drilling machine. The electrode tube passes through the guide and the vertical movement of the electrode tube is controlled. The high energy generated by the pulse power discharge is used to process microchannels on the densified C / C composite material. The pore size of the microchannel is 150-350μm.

[0010] IV. Control the worktable to move and change the perforation position. The electrode tube moves vertically up and down to perforate, and a microchannel array is processed on the densified C / C composite material to obtain an actively cooled C / C composite material workpiece.

[0011] 5. Assemble the C / C composite material actively cooled workpiece with the metal actively cooled mold to obtain the C / C composite material actively cooled assembly;

[0012] 6. The cooling working fluid is filled into the C / C composite material active cooling component by a pumping device to obtain the C / C composite material active cooling system.

[0013] Forced sweating technology is an advanced heat protection technology that utilizes a driving mechanism to controllably expel liquid or gaseous cooling media from within a composite material. This pushes the high-temperature flow away from the material surface and absorbs a large amount of heat through phase changes, maintaining a lower surface temperature and thus significantly reducing the ablation rate. This invention uses C / C composite materials as a carrier. Through efficient densification to ensure the mechanical strength of the composite material, it further utilizes digital pulse discharge via high-speed EDM to construct microchannels in situ on demand. These microchannels are combined with a high-temperature mold to form an active cooling structure. Simultaneously, the supply of liquid or gaseous cooling media is controlled, thus realizing the development of an active cooling system for C / C composite materials.

[0014] The active cooling system for C / C composite materials based on forced sweating technology of the present invention has the following beneficial effects:

[0015] 1. In this invention, C / C composite material is used as the carrier of the inorganic non-metallic matrix composite active cooling structure. The C / C composite material is an advanced ultra-high temperature heat protection material with excellent ablation resistance, and the service process will not involve major technical risks such as cooling microchannel closure.

[0016] 2. This invention adopts a method of densification followed by construction of cooling microchannels, which is completely different from the traditional method of controlling the impregnation process. It can quantitatively design and construct the size and distribution of microstructures as needed while ensuring the mechanical properties of the material, thereby significantly improving the heat protection efficiency.

[0017] 3. This invention broadens the types of cooling media, covering, but not limited to, liquid water, ethanol, liquid rocket propellants, liquid nitrogen, high-purity nitrogen, high-purity helium, and high-purity argon, thus enriching the application scenarios of active cooling systems for inorganic non-metallic composite materials. Attached Figure Description

[0018] Figure 1 These are macroscopic and microscopic photographs of the C / C composite material sample obtained in Example 1 of this invention;

[0019] Figure 2This is a macroscopic photograph of the C / C composite material actively cooled workpiece obtained in Embodiment 2 of the present invention;

[0020] Figure 3 This is a macroscopic photograph of the C / C composite material actively cooled workpiece obtained in Embodiment 4 of the present invention;

[0021] Figure 4 This is a macroscopic photograph of the C / C composite material actively cooled workpiece obtained in Embodiment 5 of the present invention;

[0022] Figure 5 This is a schematic diagram of the assembly structure of the C / C composite material active cooling component in Specific Implementation Method Six;

[0023] Figure 6 This is a schematic diagram of microchannel processing using an electrical discharge high-speed drilling machine in step three of the present invention;

[0024] Figure 7 This is a macroscopic photograph of the C / C composite material active cooling mechanism in operation as obtained in Embodiment 5 of the present invention;

[0025] Figure 8 This is a photograph of the C / C composite material active cooling mechanism during the oxyacetylene test obtained in Embodiment 5 of the present invention;

[0026] Figure 9 The graph shows the surface response temperature curves of the C / C composite active cooling mechanism obtained in Embodiment 5 of the present invention and the surface response temperature curves of conventional high-density C / C composite materials during the evaluation process.

[0027] Figure 10 This is a photograph of the C / C composite material obtained in Example 5 of the present invention after active cooling of the workpiece for oxyacetylene testing. Detailed Implementation

[0028] Specific Implementation Method 1: This implementation method, based on the C / C composite material active cooling system using forced sweating technology, is carried out according to the following steps:

[0029] I. The C / C composite material is highly densified by a densification process, and the porosity of the densified C / C composite material is 4-7 vol.%.

[0030] 2. Fix the densified C / C composite material onto the worktable of the high-speed EDM drilling machine;

[0031] 3. An electrode tube and a guide are assembled on an EDM high-speed drilling machine. The electrode tube passes through the guide and the vertical movement of the electrode tube is controlled. The high energy generated by the pulse power discharge is used to process microchannels on the densified C / C composite material. The pore size of the microchannel is 150-350μm.

[0032] IV. Control the worktable to move and change the perforation position. The electrode tube moves vertically up and down to perforate, and a microchannel array is processed on the densified C / C composite material to obtain an actively cooled C / C composite material workpiece.

[0033] 5. Assemble the C / C composite material actively cooled workpiece with the metal actively cooled mold to obtain the C / C composite material actively cooled assembly;

[0034] 6. The cooling working fluid is filled into the C / C composite material active cooling component by a pumping device to obtain the C / C composite material active cooling system.

[0035] The density of the ungraphitized C / C composite material in this embodiment is ≥1.50 g / cm³. 3 Graphitized C / C composite materials have a density ≥1.80 g / cm³. 3 .

[0036] In this embodiment, the preferred, but not limited, dimensions of the copper tube electrode are 0.10mm(D)×20cm(L), 0.15mm(D)×20cm(L), 0.20mm(D)×20cm(L), and 0.30mm(D)×50cm(L).

[0037] The sheet-like sample of the highly densified C / C composite material in this embodiment is as follows: Figure 1 As shown in the image, a physical diagram of a C / C composite material actively cooled workpiece is presented. Figure 2 As shown. This embodiment employs an active cooling structure capable of performing oxyacetylene testing, and its thickness is 10 mm, verifying that the perforation process can be applied to bulk structures with greater thickness.

[0038] This embodiment first utilizes a densification process to achieve high densification of C / C composite materials, then designs the pore size and distribution of active cooling microchannels for C / C composite materials, further processes the C / C composite materials using an EDM high-speed drilling machine, and finally assembles them with a mold to form a cooling structure and controls the active cooling system to discharge liquid or gaseous cooling medium from the inside of the microchannels as needed.

[0039] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that step one employs an ultra-high pressure impregnation carbonization process to highly densify the C / C composite material. The process is as follows:

[0040] Step a: Introduce the carbon source precursor into the carbon fiber preform using a vacuum impregnation method, control the vacuum degree to be no higher than 30 Pa and the holding time to be 3-5 h, to obtain a carbon fiber preform impregnated with the precursor.

[0041] Step b: The carbon fiber preform impregnated with the precursor is placed in a rubber sleeve and subjected to ultra-high pressure impregnation treatment by cold isostatic pressing. The impregnation pressure is controlled to be no less than 200 MPa and the holding time is 2 to 3 hours. Then it is placed in an oven for curing treatment to obtain the cured composite material.

[0042] Step c: Place the cured composite material system in a pyrolysis furnace and pyrolyze it at a temperature of 800-1500℃ for 1-2 hours to obtain C / C composite material;

[0043] Step d: Place the C / C composite material in a graphitization furnace and graphitize it at a temperature of 2000-2950℃ for 1-2 hours to obtain a dense C / C composite material.

[0044] Step e: Immerse the dense C / C composite material in the carbon source precursor and repeat steps a to d multiple times to obtain a highly dense C / C composite material.

[0045] The carbon source precursors in this embodiment include, but are not limited to, C / C composite carbon source materials such as phenolic resin, furfuryl ketone resin and polyaryl acetylene resin. The viscosity of the carbon source precursor can be adjusted to below 200 mPa·s by adding common solvents such as ethanol and acetone.

[0046] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 2 in that the carbon source precursor mentioned in step a is phenolic resin, furfuryl ketone resin, or polyaryl acetylene resin.

[0047] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the pore size of the microchannel in step three is 200-300 μm.

[0048] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that the diameter of the electrode tube in step 3 is 0.1 to 0.4 mm, and the length of the electrode tube is 20 to 50 cm.

[0049] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the metal active cooling mold in step five includes an outer mold 2, a pagoda bolt 3, an inner mold 4, and a washer 5. The outer mold 2 is cylindrical, with a through hole at one end and a pagoda bolt 3 at the other end. The C / C composite material active cooling workpiece 1 is inserted into the through hole of the outer mold 2. The cylindrical inner mold 4 is fitted onto the inner wall of the outer mold 2, and a washer 5 is placed between the inner mold 4 and the pagoda bolt 3.

[0050] The structural diagram of the C / C composite material active cooling component in this embodiment is as follows: Figure 5As shown. The materials of the active cooling mold include, but are not limited to, metallic copper, stainless steel, graphite and C / C composite materials. The general assembly gap is ≤0.10mm, and the gap is sealed with materials such as rubber rings or polytetrafluoroethylene tape.

[0051] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that the C / C composite material actively cooled workpiece 1 is in the shape of a frustum or cylinder, with a circular flange at the bottom of the frustum shape.

[0052] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that the thickness of the C / C composite material actively cooled workpiece 1 is 10-20 mm.

[0053] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the pumping device described in step six is ​​a peristaltic pump or a high-pressure gas cylinder.

[0054] In this embodiment, the liquid-phase cooling medium is pumped using a peristaltic pump. The gas-phase cooling medium is supplied from a high-pressure gas cylinder with an internal pressure of 15 MPa. The gas pressure and flow rate are reduced by a pressure-reducing valve, thereby controlling the supply of the gaseous cooling medium. The peristaltic pump flow rate is ≤100 mL / min, and the high-pressure gas cylinder flow rate is ≤100 mL / min.

[0055] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the cooling medium mentioned in step 6 is water, ethanol, liquid rocket propellant, liquid nitrogen, high-purity nitrogen, high-purity helium, or high-purity argon.

[0056] In this embodiment, the purity of high-purity nitrogen, high-purity helium, or high-purity argon is higher than 99%.

[0057] Example 1: This example demonstrates an active cooling system for C / C composite materials based on forced sweating technology, implemented according to the following steps:

[0058] I. The C / C composite material is highly densified by using an ultra-high pressure impregnation carbonization densification process, and the porosity of the densified C / C composite material is 6 vol.%.

[0059] 2. Fix the densified C / C composite material onto the worktable of the high-speed EDM drilling machine;

[0060] 3. An electrode tube and guide are assembled on the high-speed EDM drilling machine. A copper tube electrode with a diameter of Ф=0.20mm is selected. The electrode tube passes through the guide, and the vertical movement of the electrode tube is controlled. The high energy generated by the pulse power supply discharge is used to process microchannels on the densified C / C composite material. The pore size of the microchannel is about 250μm. The high-pressure cooling water in the electrode tube is used to promptly discharge the processing products inside the microchannel and cool the electrode tube. The pulse power supply is controlled with pulse width at level 1-2 (this parameter is related to the surface roughness of the processed hole and the degree of electrode consumption. The larger the pulse width, the greater the electrode consumption and the rougher the processed surface), pulse interval at level 1-5 (this parameter is related to the processing stability and the ease of waste discharge. The larger the resin, the easier the discharge, but the longer the processing time), and power amplifier at level 1-2 (the larger this parameter, the greater the processing current and the higher the efficiency, but the greater the electrode consumption). This achieves a processing voltage of 40V-50V and a processing current of 6A-10A.

[0061] 4. Control the worktable to move and change the perforation position. The electrode tube moves vertically up and down to perforate, and a microchannel array (66 microchannels in total) with a "HIT" pattern is processed on the densified C / C composite material to obtain an actively cooled C / C composite material workpiece.

[0062] 5. Assemble the C / C composite material actively cooled workpiece with the metal actively cooled mold. The metal actively cooled mold includes an outer mold 2, a pagoda bolt 3, an inner mold 4, and a washer 5. The outer mold 2 is cylindrical, with a through hole at one end and a pagoda bolt 3 at the other end. The C / C composite material actively cooled workpiece 1 is inserted into the through hole of the outer mold 2. The cylindrical inner mold 4 is fitted onto the inner wall of the outer mold 2. A washer 5 is placed between the inner mold 4 and the pagoda bolt 3 to obtain the C / C composite material actively cooled assembly.

[0063] VI. Using a peristaltic pump as a pumping device for liquid phase cooling medium, and controlling the flow rate of the peristaltic pump to supply liquid phase cooling medium water as needed, an active cooling system for C / C composite materials is obtained.

[0064] The high-speed EDM drilling machine used in this embodiment is the MS-DZ430A model drilling machine from Suzhou Amazone Machine Tool Co., Ltd.

[0065] The process of achieving high densification of C / C composite materials using ultra-high pressure impregnation carbonization in this embodiment is as follows:

[0066] Step a: The carbon source precursor is introduced into the carbon fiber preform by vacuum impregnation. The vacuum degree is controlled at 100 Pa and the holding time is 3 h to obtain the carbon fiber preform impregnated with the precursor. The carbon source precursor is polyarylene acetylene resin, the solvent is acetone, and the acetone content is 10 vol.%.

[0067] Step b: The carbon fiber preform impregnated with the precursor is placed in a rubber sleeve and subjected to ultra-high pressure impregnation treatment by cold isostatic pressing. The impregnation pressure is controlled at 100 MPa and the holding time is 2 hours. Then it is placed in an oven for curing treatment to obtain the cured composite material.

[0068] Step c: Place the cured composite material system in a pyrolysis furnace and pyrolyze it at 1200℃ for 2 hours to obtain C / C composite material;

[0069] Step d: Place the C / C composite material in a graphitization furnace and graphitize it at 2850℃ for 2 hours to obtain a dense C / C composite material.

[0070] Step e: Immerse the dense C / C composite material in the carbon source precursor and repeat steps a to d multiple times to obtain a highly dense C / C composite material.

[0071] Example 2: This example differs from Example 1 in that the C / C composite material is processed into a frustum-shaped sample of 15mm (Ф1)×7mm (H1)@20mm (Ф2)×3mm (H2), and a single microchannel is processed on the densified C / C composite material.

[0072] Example 3: This example differs from Example 1 in that the C / C composite material is processed into a frustum-shaped sample of 15mm (Ф1)×7mm (H1)@20mm (Ф2)×3mm (H2). A double-hole microchannel is processed on the densified C / C composite material, and liquid nitrogen, the liquid phase cooling medium, is supplied as needed by controlling the flow rate of the peristaltic pump.

[0073] Example 4: This example differs from Example 1 in that the C / C composite material is processed into a frustum-shaped sample of 15mm (Ф1)×7mm (H1)@20mm (Ф2)×3mm (H2). Three-hole microchannels are processed on the densified C / C composite material, and the liquid cooling working medium ethanol is supplied as needed by controlling the flow rate of the peristaltic pump.

[0074] Example 5: This example differs from Example 1 in that the C / C composite material is processed into a frustum-shaped sample of 15mm (Ф1)×7mm (H1)@20mm (Ф2)×3mm (H2). Seven microchannels are processed on the densified C / C composite material, and the liquid phase cooling medium is supplied as needed by controlling the flow rate of the peristaltic pump.

[0075] Oxyacetylene ablation tests were conducted on the C / C composite cooling mechanism and the C / C composite material in Example 5 for comparison. The tests showed that under the same oxygen and acetylene flow rates, the high-density C / C composite material (1.90 g / cm³) without active cooling design... 3The surface response temperature of the high-density C / C composite active cooling structure exceeded 1700℃, while the surface response temperature of the high-density C / C composite active cooling structure did not exceed 1300℃. The peak temperature difference between the two exceeded 400℃, demonstrating excellent cooling effect. After the experiment, the ablation resistance of the C / C composite was quantitatively characterized. The linear ablation rate of the high-density C / C composite designed for active cooling was approximately 8.1 × 10⁻⁶. -3 The surface structure of the C / C composite active cooling structure remained intact and exhibited non-ablative characteristics, while the speed was measured in mm / s. The experimental results verified the advanced non-ablative capability of the C / C composite active cooling technology.

[0076] This invention develops an active cooling system for C / C composite materials based on forced sweating technology. Using small-aperture copper tubes as electrodes and digital pulse discharge, the invention achieves on-demand design and construction of active cooling microchannels for C / C composite materials. The controlled overflow of gaseous or liquid cooling media pushes the high-temperature inflow away from the boundary layer, thus significantly reducing the material's surface temperature and greatly improving its ablation resistance. This invention features an advanced heat protection concept, simple implementation technology, excellent heat protection effect, and customizable structure. Furthermore, this method has excellent versatility and can be applied to other inorganic non-metallic matrix composite materials, significantly improving their ablation resistance. This technology is expected to be widely used in the heat protection structures of new high-speed aircraft, contributing to higher speeds, longer service life, better thermal stealth performance, and reusability.

Claims

1. A method for preparing a C / C composite material active cooling system based on forced sweating technology, characterized in that... The preparation method is carried out according to the following steps: I. The C / C composite material is highly densified by an ultra-high pressure impregnation carbonization densification process, resulting in a porosity of 4~7 vol.% for the densified C / C composite material.

2. Fix the densified C / C composite material onto the worktable of the high-speed EDM drilling machine; 3. An electrode tube and a guide are assembled on an EDM high-speed drilling machine. The electrode tube passes through the guide and the vertical movement of the electrode tube is controlled. The high energy generated by the pulse power discharge is used to process microchannels on the densified C / C composite material. The pore size of the microchannel is 150~350 μm. IV. Control the worktable to move and change the perforation position. The electrode tube moves vertically up and down to perforate, and a microchannel array is processed on the densified C / C composite material to obtain an actively cooled C / C composite material workpiece.

5. Assemble the C / C composite material actively cooled workpiece with the metal actively cooled mold to obtain the C / C composite material actively cooled assembly; 6. The cooling working fluid is filled into the C / C composite material active cooling component by a pumping device to obtain the C / C composite material active cooling system; The process of using ultra-high pressure impregnation carbonization densification technology to highly densify the C / C composite material in step one is as follows: Step a: Introduce the carbon source precursor into the carbon fiber preform using a vacuum impregnation method, control the vacuum degree to be no higher than 30 Pa and the holding time to be 3~5 h, to obtain a carbon fiber preform impregnated with the precursor. Step b: The carbon fiber preform impregnated with the precursor is placed in a rubber sleeve and subjected to ultra-high pressure impregnation treatment by cold isostatic pressing. The impregnation pressure is controlled to be no less than 200 MPa and the holding time is 2 to 3 hours. Then it is placed in an oven for curing treatment to obtain the cured composite material. Step c: Place the cured composite material in a pyrolysis furnace and pyrolyze it at a temperature of 800~1500℃ for 1~2 hours to obtain C / C composite material; Step d: Place the C / C composite material in a graphitization furnace and graphitize it at a temperature of 2000~2950℃ for 1~2 hours to obtain a dense C / C composite material. Step e: Immerse the dense C / C composite material in the carbon source precursor and repeat steps a to d multiple times to obtain a highly dense C / C composite material. In step five, the metal active cooling mold includes an outer mold (2), a pagoda bolt (3), an inner mold (4), and a washer (5). The outer mold (2) is cylindrical, with a through hole at one end and a pagoda bolt (3) at the other end. The C / C composite material active cooling workpiece (1) is inserted into the through hole of the outer mold (2), and the cylindrical inner mold (4) is fitted on the inner wall of the outer mold (2). A washer (5) is provided between the inner mold (4) and the pagoda bolt (3). The C / C composite material active cooling workpiece (1) is frustum-shaped or cylindrical, with a circular flange at the bottom of the frustum shape.

2. The preparation method of the C / C composite active cooling system based on forced sweating technology according to claim 1, characterized in that... The carbon source precursor mentioned in step a is phenolic resin, furfuryl ketone resin, or polyaryl acetylene resin.

3. The preparation method of the C / C composite active cooling system based on forced sweating technology according to claim 1, characterized in that... In step three, the pore size of the microchannel is 200~300 μm.

4. The preparation method of the C / C composite material active cooling system based on forced sweating technology according to claim 1, characterized in that... In step three, the diameter of the electrode tube is 0.1~0.4 mm and the length of the electrode tube is 20~50 cm.

5. The preparation method of the C / C composite active cooling system based on forced sweating technology according to claim 1, characterized in that... The thickness of the C / C composite material actively cooled workpiece (1) is 10~20 mm.

6. The preparation method of the C / C composite material active cooling system based on forced sweating technology according to claim 1, characterized in that... The pumping device mentioned in step six is ​​a peristaltic pump or a high-pressure gas cylinder.

7. The preparation method of the C / C composite active cooling system based on forced sweating technology according to claim 1, characterized in that... The cooling medium mentioned in step six is ​​water, ethanol, liquid rocket propellant, liquid nitrogen, high-purity nitrogen, high-purity helium, or high-purity argon.

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