Spacecraft programmable thermal protection ceramic metal dot array superstructure under extreme environment

Abstract

This invention relates to a programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments, belonging to the field of spacecraft thermal protection technology. It comprises multiple body-centered cubic lattice cells arranged periodically in three-dimensional space to form an isotropic three-dimensional network structure. Each body-centered cubic lattice cell includes eight lattice connecting rods, which are rod-shaped structures. The eight connecting rods intersect at a central point, and any two adjacent connecting rods have the same angle relative to the central point, forming a cubic unit configuration body-centered cubic lattice cell. This invention solves the problem of traditional thermal protection structures failing to simultaneously address heat dissipation capacity and thermal shock protection, providing an innovative solution for thermal protection of spacecraft in extreme space environments.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft thermal protection technology and relates to a programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments. Background Technology

[0002] As space missions become increasingly complex and the thermal environments they face become more severe, higher demands are being placed on advanced thermal protection technologies for spacecraft. These technologies must not only adapt to the high vacuum, large temperature variations, and strong radiation of the space environment, but also possess the ability to withstand potential short-term extreme thermal shocks. Traditional spacecraft protective structures offer limited protection capabilities and are bulky, making them unsuitable for the needs of future space missions. This necessitates that spacecraft protective structures move beyond simple thermal protection and transform into advanced structures with adjustable, programmable, thermodynamically coordinated, multifunctional, and lightweight properties.

[0003] Superstructures are special periodic structures meticulously designed by humans. By controlling cell size, topological configuration, and the arrangement of cells, extraordinary physical properties can be achieved. Simultaneously, superstructures can regulate complex physical processes involving thermo-mechanical coupling, and through innovative structural design, integrate multiple protective functions to meet the protection requirements of spacecraft in extreme thermal environments.

[0004] In recent years, researchers have conducted a great deal of research in the field of programmable thermal protection technology, but there are still problems such as difficulty in effectively balancing heat dissipation capacity and thermal shock protection. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments. This solves the problem that traditional thermal protection structures cannot simultaneously achieve both heat dissipation capacity and thermal shock protection, and provides an innovative solution for thermal protection of spacecraft in extreme space environments.

[0006] The solution of the present invention is: A programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments comprises multiple body-centered cubic lattice cells. These cells are periodically arranged in three-dimensional space to form an isotropic three-dimensional network structure. Each body-centered cubic lattice cell includes eight lattice connecting rods. These connecting rods are rod-shaped structures. The eight connecting rods intersect at the center point, and any two adjacent connecting rods have the same angle relative to the center point, forming a cubic unit configuration body-centered cubic lattice cell.

[0007] In the aforementioned space extreme environment, the spacecraft programmable thermal protection ceramic metal lattice superstructure has a hollow channel at the axis of the lattice connecting rod; the hollow channel is a columnar structure; all eight hollow channels are connected through the center point; and the hollow channels are filled with liquid alloy.

[0008] In the aforementioned space extreme environment, the spacecraft programmable thermal protection ceramic-metal lattice superstructure has the following characteristics: the side length of the cubic unit is L, which is 16-19 mm; the diameter of the lattice connecting rod is D, which is 3-5 mm; and the diameter of the hollow channel is d, which is 1.5-4.5 mm.

[0009] In the aforementioned space extreme environment, the spacecraft programmable thermal protection ceramic-metal lattice superstructure uses ZrO2 ceramic material for the lattice connecting rods and In51Bi32.5Sn16.5 alloy for the liquid alloy, thereby achieving synergistic enhancement between the ceramic and metal phases.

[0010] The fabrication method of the spacecraft programmable thermal protection ceramic-metal lattice superstructure for the aforementioned extreme space environment is as follows: A geometric model of a lattice superstructure was created using Solidworks and exported as an STL file. A stereolithography 3D printer, namely an SLA printer, is used to print according to the geometric model to generate a lattice superstructure green body; The lattice superstructure green body is placed in a high-temperature furnace for degreasing and sintering to obtain a lattice superstructure with hollow channels. Liquid alloy is injected into the hollow channels of a lattice superstructure; After injection, the material is placed in air to cool and solidify, thus obtaining a lattice superstructure.

[0011] In the aforementioned extreme space environment, for spacecraft programmable thermal protection ceramic-metal lattice superstructures, the SLA printer uses a laser wavelength of 355nm, a laser output power of 500mW, and a single-layer printing thickness of 50mm. The maximum size of the printed sample is 200mm×200mm×200mm; the solid content of the ZrO2 ceramic slurry is 52 vol.%, the particle size is 500nm, and the viscosity is 20000–25000cps.

[0012] In the aforementioned space programmable thermal protection ceramic-metal lattice superstructure for spacecraft under extreme space conditions, the degreasing process is as follows: in an air atmosphere, at a temperature of 650°C for two hours; the sintering process is as follows: in an air atmosphere, at a temperature of 1650°C for two hours; to achieve complete densification.

[0013] In the aforementioned extreme space environment, the method for injecting liquid alloys into the spacecraft's programmable thermal protection ceramic-metal lattice superstructure is as follows: The lattice superstructure with hollow channels and the In51Bi32.5Sn16.5 alloy block were placed on a constant temperature heating platform; the lattice superstructure with hollow channels was fully preheated to 100℃, and the In51Bi32.5Sn16.5 alloy block was melted into a liquid state. Liquid In51Bi32.5Sn16.5 was drawn into the hollow channel and injected using a syringe with a 34G needle. During the injection, a heating sleeve was placed on the outer wall of the syringe to stabilize the temperature at 70°C, ensuring that the In51Bi32.5Sn16.5 alloy remained completely liquid throughout the entire preparation process.

[0014] In the aforementioned extreme space environment, the In51Bi32.5Sn16.5 alloy of the spacecraft programmable thermal protection ceramic metal lattice superstructure changes from liquid to solid state. During this process, the temperature of the upper surface of the lattice superstructure is monitored from directly above using an infrared thermal imager. This allows for the extraction of temperature field data of the lattice superstructure during the heating process. The temperature data of the lattice superstructure is obtained by calculating the average temperature of the temperature field on the upper surface of the lattice superstructure.

[0015] In the aforementioned extreme space environment, the programmable thermal protection ceramic-metal lattice superstructure for spacecraft has a thermal conductivity of 2 W / m•K for the lattice connecting rods and 30 W / m•K for the liquid alloy. By controlling the ratio d / D of the diameter of the hollow channel in the programmable thermal protection ceramic-metal lattice superstructure to the diameter of the lattice connecting rods, the volume ratio of the liquid alloy can be adjusted. By controlling the ratio D / L of the diameter of the lattice connecting rods to the side length of the cubic unit, the relative density of the lattice superstructure can be adjusted. Based on these two adjustment methods, programmable thermal management is achieved.

[0016] The advantages of this invention compared to the prior art are: (1) By controlling the volume ratio of ceramic phase to metal phase and the overall size of cell in the lattice superstructure, the present invention can effectively adjust the heat transfer performance of the superstructure, improve the heat dissipation capacity of the spacecraft thermal protection sample under space thermal load and the buffering performance under thermal shock in extreme environments. (2) In the programmable thermal protection ceramic-metal lattice superstructure for spacecraft thermal protection in extreme environments manufactured by the present invention, the unit cell has periodic characteristics, which means it can be expanded in three orthogonal spatial directions; (3) By combining the effective adjustment of the heat transfer performance of the superstructure with the structural design of the lattice superstructure, this invention solves the problem that the heat dissipation capacity and thermal shock protection of traditional thermal protection structures are difficult to balance, and provides an innovative solution for the thermal protection of spacecraft in extreme space environments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the body-centered cubic lattice cell structure of the present invention; Figure 2 This is a flowchart illustrating the fabrication process of the lattice superstructure of the present invention. Figure 3 This is a schematic diagram of the heat transfer performance test of the lattice superstructure of the present invention; Figure 4 This is a phase change heat transfer time-temperature curve of the lattice superstructure of the present invention; Figure 5 This is a simulation cloud map of the temperature field of the lattice superstructure of the present invention under thermal load conditions; Figure 6 This is a simulation cloud diagram of the velocity field of the lattice superstructure of the present invention under thermal load conditions; Figure 7 This is a simulation cloud diagram of the liquid phase fraction of the lattice superstructure of the present invention under thermal load; Figure 8 This is a comparison of the time-temperature curves of the heat transfer process between the lattice superstructure and the single-phase ceramic lattice structure of the present invention. Figure 9 This is a comparison diagram of the equivalent heat transfer coefficients of the lattice superstructure and the single-phase ceramic lattice structure of the present invention. Figure 10 This is a schematic diagram illustrating the application of the periodic array of the lattice superstructure of this invention. Detailed Implementation

[0018] The present invention will be further described below with reference to the embodiments.

[0019] This invention provides a programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments. It can effectively adjust the heat transfer performance of the superstructure, improve the heat dissipation capacity of the thermal protection prototype for spacecraft under space thermal loads and the buffering performance under thermal shock in extreme environments.

[0020] Programmable thermal protection ceramic-metal lattice superstructures for spacecraft in extreme space environments, such as Figure 1 As shown, it includes multiple body-centered cubic lattice cells; these cells are periodically arranged in three-dimensional space, forming an isotropic three-dimensional network structure; each cell includes eight lattice connecting rods 1; each connecting rod 1 is a rod-shaped structure; the eight connecting rods 1 intersect at a central point, and any two adjacent connecting rods 1 have the same angle relative to the central point, forming a cubic unit configuration of the body-centered cubic lattice cell. The body-centered cubic lattice cell has a periodic characteristic, meaning it can expand in three orthogonal spatial dimensions to construct a three-dimensional protective structure.

[0021] A hollow channel 2 is provided at the axis of the lattice connecting rod 1; the hollow channel 2 is a columnar structure; all eight hollow channels 2 are connected through the center point; the hollow channels 2 are filled with liquid alloy. The specific dimensions of this invention are as follows: the side length of the cubic unit is L, where L is 16-19mm; the diameter of the lattice connecting rod 1 is D, where D is 3-5mm; and the diameter of the hollow channel 2 is d, where d is 1.5-4.5mm.

[0022] In terms of material selection, the lattice connecting rod 1 of the present invention is made of ZrO2 ceramic material; the liquid alloy is In51Bi32.5Sn16.5 alloy; thus achieving synergistic enhancement between the ceramic phase and the metal phase.

[0023] Each cubic element has eight vertices and a node at its geometric center. Vertex nodes and the body center node are connected by a connecting rod 1 with a circular cross-section and a diameter of D. The overall characteristic dimension of the cubic element is L. The feature of this design is the inclusion of a hollow channel 2 with a continuous inner cavity within the connecting rod 1, transforming the solid network into a continuous three-dimensional hollow channel network. This hollow channel is a circular cross-section channel connecting the vertex nodes and the body center node along the body diagonal. The inner diameter of the hollow channel is d, and it is filled with a functional liquid alloy.

[0024] like Figure 2 As shown, the fabrication method of the lattice superstructure is as follows: A geometric model of a lattice superstructure was created using Solidworks and exported as an STL file.

[0025] A stereolithography 3D printer, also known as an SLA printer, is used to print according to the geometric model, generating a lattice superstructure green body.

[0026] The SLA printer uses a laser wavelength of 355nm, a laser output power of 500mW, and a single-layer printing thickness of 50mm. The maximum size of the printed sample is 200mm×200mm×200mm; the solid content of the ZrO2 ceramic slurry is 52 vol.%, the particle size is 500nm, and the viscosity is 20000–25000cps.

[0027] The lattice superstructure green body is placed in a high-temperature furnace for degreasing and sintering to obtain a lattice superstructure with hollow channels 2.

[0028] The specific degreasing process is as follows: in an air atmosphere, the temperature is 650°C and the time is two hours; the sintering process is as follows: in an air atmosphere, the temperature is 1650°C and the time is two hours; in order to achieve complete densification.

[0029] Liquid alloy was injected into the hollow channel 2 of the lattice superstructure.

[0030] The method for injecting liquid alloy is as follows: The lattice superstructure with hollow channel 2 and the In51Bi32.5Sn16.5 alloy block are placed on a constant temperature heating platform; the lattice superstructure with hollow channel 2 is fully preheated to 100℃, and the In51Bi32.5Sn16.5 alloy block is melted into a liquid state.

[0031] A syringe with a 34G needle and an inner diameter of approximately 0.23 mm was used to draw liquid In51Bi32.5Sn16.5 and inject it into the hollow channel 2. During the injection process, a heating sleeve was placed on the outer wall of the syringe to stabilize the temperature at 70°C, ensuring that the In51Bi32.5Sn16.5 alloy remained completely liquid throughout the entire preparation process.

[0032] After injection, the material is placed in air to cool and solidify, thus obtaining a lattice superstructure.

[0033] like Figure 3 As shown, the method for testing the heat transfer performance of the lattice superstructure is as follows: the temperature of the upper surface of the lattice superstructure is monitored from directly above using an infrared thermal imager to extract the temperature field data of the lattice superstructure during the heating process, and the temperature data of the lattice superstructure is obtained by calculating the average temperature of the temperature field on the upper surface of the lattice superstructure.

[0034] The thermal conductivity of lattice connecting rod 1 is 2 W / m•K; the thermal conductivity of the liquid alloy is 30 W / m•K. The volume ratio of the liquid alloy is adjusted by controlling the ratio d / D of the diameter of the hollow channel in the programmable thermally protective ceramic-metal lattice superstructure to the diameter of lattice connecting rod 1. The relative density of the lattice superstructure is adjusted by controlling the ratio D / L of the diameter of lattice connecting rod 1 to the side length of the cubic unit. Based on these two adjustment methods, programmable thermal management is achieved. Through various cell geometric parameter control methods, the performance design space of the programmable thermally protective ceramic-metal lattice superstructure can be greatly enriched, giving it the advantages of wide adjustability and strong adaptability.

[0035] Figure 4 This study demonstrates the phase change heat transfer process of a programmable thermally protective ceramic-metal lattice superstructure rod under thermal load. The introduction of liquid alloys endows the lattice superstructure with phase change heat storage capabilities, enabling buffering against thermal shock. Figures 5-7The temperature field changes, velocity field evolution, and volume fraction during the melting process of the programmable thermal protective ceramic-metal lattice superstructure under thermal load are demonstrated. Under thermal conditions, when the load temperature is below the melting point of the liquid alloy, the superstructure does not undergo a phase transition and maintains high thermal conductivity to accelerate the dissipation of heat accumulated on the surface of the solar array. When subjected to transient thermal shock or rapid fluctuations in ambient temperature, the liquid alloy undergoes a solid-liquid phase transition and absorbs a large amount of overload heat energy, achieving a thermal buffering effect and maintaining the temperature stability of the protective structure itself.

[0036] Figure 8 and Figure 9 The time-temperature curves and equivalent thermal conductivity of the heat transfer process of a programmable thermal protective ceramic-metal lattice superstructure with a volume fraction of 50% and a single-phase ceramic lattice superstructure are compared under similar cell sizes, strut diameters, and thermal loads. It can be seen that the high thermal conductivity of the liquid alloy can significantly improve the heat dissipation capacity of the ceramic lattice, helping to solve the problem of insufficient heat dissipation in spacecraft protective components.

[0037] Figure 10 This diagram illustrates the application of the programmable thermally protective ceramic-metal lattice superstructure of this invention in spacecraft skin structures under extreme environments. It should be noted that the superstructure filling method shown in the diagram is only illustrative. In practice, the filling method can be flexibly adjusted according to the spacecraft's shape under extreme environments, as well as the specific application scenarios and mission requirements.

[0038] This invention enables effective adjustment of the heat transfer performance of a lattice superstructure by controlling the volume ratio of the ceramic phase to the metal phase and the overall size of the cell. This improves the heat dissipation capacity of the spacecraft thermal protection prototype under space thermal load and its buffering performance under thermal shock in extreme environments.

[0039] In the programmable thermal protection ceramic-metal lattice superstructure for spacecraft thermal protection in extreme environments manufactured by this invention, the unit cell has periodic characteristics, which means it can be expanded in three orthogonal spatial directions.

[0040] This invention solves the problem of traditional thermal protection structures being unable to simultaneously address heat dissipation capacity and thermal shock protection by combining effective adjustment of the heat transfer performance of the superstructure with the structural design of the lattice superstructure, providing an innovative solution for thermal protection of spacecraft in extreme space environments.

[0041] 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 programmable thermal protection ceramic metal dot array superstructure for spacecraft in extreme environments, characterized in that: It includes multiple body-centered cubic lattice cells; the multiple body-centered cubic lattice cells are arranged periodically in three-dimensional space to form an isotropic three-dimensional network structure; the body-centered cubic lattice cells include 8 lattice connecting rods (1). The lattice connecting rod (1) is a rod-shaped structure; the eight lattice connecting rods (1) intersect each other at the center point, and any two adjacent lattice connecting rods (1) have the same angle relative to the center point, forming a body-centered cubic lattice cell with a cubic unit configuration.

2. The programmable thermal protection ceramic-metallic dot-lattice superstructure for spacecraft in extreme environments of space according to claim 1, characterized in that: A hollow channel (2) is provided at the axis of the dot matrix connecting rod (1); the hollow channel (2) is a columnar structure; all eight hollow channels (2) are connected through the center point; the hollow channels (2) are filled with liquid alloy.

3. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments according to claim 2, characterized in that: Let the side length of the square unit be L, where L is 16-19mm; let the diameter of the lattice connecting rod (1) be D, where D is 3-5mm; let the diameter of the hollow channel (2) be d, where d is 1.5-4.5mm.

4. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments according to claim 2, characterized in that: The lattice connecting rod (1) is made of ZrO2 ceramic material; the liquid alloy is In51Bi32.5Sn16.5 alloy; thus achieving synergistic enhancement between the ceramic phase and the metal phase.

5. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments according to claim 4, characterized in that: The fabrication method of lattice superstructures is as follows: A geometric model of a lattice superstructure was created using Solidworks and exported as an STL file. A stereolithography 3D printer, namely an SLA printer, is used to print according to the geometric model to generate a lattice superstructure green body; The lattice superstructure green body was placed in a high-temperature furnace for degreasing and sintering to obtain a lattice superstructure with hollow channels (2). Liquid alloy was injected into the hollow channel (2) of the lattice superstructure; After injection, the material is placed in air to cool and solidify, thus obtaining a lattice superstructure.

6. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments according to claim 5, characterized in that: The SLA printer uses a laser wavelength of 355nm, a laser output power of 500mW, and a single-layer printing thickness of 50mm. The maximum size of the printed sample is 200mm×200mm×200mm; the solid content of the ZrO2 ceramic slurry is 52 vol.%, the particle size is 500nm, and the viscosity is 20000–25000cps.

7. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft under extreme space environments according to claim 5, characterized in that: The degreasing process is carried out in an air atmosphere at a temperature of 650°C for two hours; the sintering process is carried out in an air atmosphere at a temperature of 1650°C for two hours. To achieve complete densification.

8. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments according to claim 5, characterized in that: The method for injecting liquid alloy is as follows: The lattice superstructure with hollow channels (2) and the In51Bi32.5Sn16.5 alloy block were placed on a constant temperature heating platform; heated to 100°C, the lattice superstructure with hollow channels (2) was fully preheated, and the In51Bi32.5Sn16.5 alloy block was melted into liquid. Liquid In51Bi32.5Sn16.5 was drawn into the hollow channel (2) using a syringe with a 34G needle. During the injection process, a heating sleeve was placed on the outer wall of the syringe to stabilize the temperature at 70°C. This ensured that the In51Bi32.5Sn16.5 alloy remained completely liquid throughout the entire preparation process.

9. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft under extreme space environments according to claim 8, characterized in that: The method for testing the heat transfer performance of lattice superstructures is as follows: The temperature of the upper surface of the lattice superstructure is monitored from directly above using an infrared thermal imager, enabling the extraction of temperature field data during the heating process. The temperature data of the lattice superstructure is obtained by calculating the average temperature of the upper surface temperature field.

10. The programmable thermal protection ceramic-metal lattice superstructure for spacecraft in extreme space environments according to claim 2, characterized in that: The thermal conductivity of the lattice connecting rod (1) is 2 W / m•K; the thermal conductivity of the liquid alloy is 30 W / m•K; the volume ratio of the liquid alloy can be adjusted by controlling the ratio d / D of the diameter of the hollow channel in the programmable thermal protection ceramic metal lattice superstructure to the diameter of the lattice connecting rod (1); the relative density of the lattice superstructure can be adjusted by controlling the ratio D / L of the diameter of the lattice connecting rod (1) to the side length of the cubic unit; based on the above two adjustment methods, programmable thermal management is realized.

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