A honeycomb-filled multifunctional thermal protection structure and method of construction thereof

Abstract

This invention discloses a honeycomb-filled multifunctional thermal protection structure and its construction method, belonging to the technical field of aerospace materials. It includes a load-bearing heat dissipation layer and a load-bearing heat insulation layer, both of which have macroscopic and mesoscopic structures. The load-bearing heat dissipation layer is a thin layer of high thermal conductivity C / C composite material, and its mesoscopic structure is a three-dimensional woven structure. The load-bearing heat insulation layer is composed of low thermal conductivity C / C honeycomb and porous insulation material, and its mesoscopic structure is a plain weave structure. The invention includes the following steps: First, a dual-scale geometric model is established using 3D modeling software; second, a high-fidelity dual-scale mathematical model is established based on the actual usage environment and conditions; then, the heat protection, heat insulation, and mechanical properties of the honeycomb-filled multifunctional thermal protection structure are simulated using finite element software; finally, the final design is determined by comprehensively evaluating the heat protection, heat insulation, mechanical properties, and lightweight level of the honeycomb-filled multifunctional thermal protection structure.

Description

Technical Field

[0001] This invention belongs to the technical field of aerospace materials, and in particular relates to a honeycomb-filled multifunctional thermal protection structure and its construction method. Background Technology

[0002] The next generation of hypersonic vehicles will undertake missions with higher Mach numbers and longer flight times, which means facing more severe aerodynamic and thermal environments. This places higher demands on the high-temperature resistance, thermal insulation, mechanical properties, and ablation resistance of thermal protection materials. On the one hand, the high heat flux on the surface of thermal protection materials will cause the surface temperature to rise rapidly. To reduce the accumulation of energy on the surface and prevent material burn-out, high thermal conductivity materials are needed to dissipate surface heat, reduce surface temperature, and minimize surface ablation. On the other hand, to protect the safety of personnel and equipment inside the vehicle, the temperature on the back of the material cannot be too high, requiring the thermal insulation area of ​​the material to have good thermal insulation performance. In addition, traditional thermal protection materials account for too large a mass of the entire vehicle, reducing the weight of the payload. Lightweight thermal protection materials have always been a goal pursued by researchers. In the past, thermal protection materials usually only played a single protective function in thermal protection systems. If thermal protection materials could also serve as load-bearing structures, the overall weight of the system would be greatly reduced. Currently, there is an urgent need in engineering for lightweight and multifunctional integrated thermal protection materials. Few existing materials can simultaneously achieve a lightweight, multifunctional integrated design, and reports on thermal protection materials that also perform load-bearing functions are even rarer. Therefore, there is an urgent need for a honeycomb-filled multifunctional thermal protection structure and its construction method to overcome the problems of traditional thermal protection materials, such as high mass proportion and poor high-temperature resistance. Summary of the Invention

[0003] The purpose of this invention is to provide a honeycomb-filled multifunctional thermal protection structure and its construction method, which solves the problems of large mass ratio and poor high-temperature resistance of traditional thermal protection materials.

[0004] To achieve the above objectives, the present invention provides a honeycomb-filled multifunctional thermal protection structure, comprising a load-bearing heat dissipation layer and a load-bearing heat insulation layer, wherein both the load-bearing heat dissipation layer and the load-bearing heat insulation layer comprise macroscopic and microscopic structures.

[0005] The heat dissipation layer is made of a thin layer of C / C composite material with high thermal conductivity. The microstructure of the heat dissipation layer is a three-dimensional woven structure. The three-dimensional woven structure includes the warp yarns of the heat dissipation layer, the weft yarns of the heat dissipation layer that are intersected with the warp yarns of the heat dissipation layer, the connecting yarns of the heat dissipation layer that connect the warp yarns and the weft yarns of the heat dissipation layer, and the substrate of the heat dissipation layer.

[0006] The load-bearing heat insulation layer is composed of low thermal conductivity C / C honeycomb and porous heat insulation material. The microstructure of the load-bearing heat insulation layer is a plain weave structure, which includes the warp yarns of the load-bearing heat insulation layer, the weft yarns of the load-bearing heat insulation layer intersecting with the warp yarns of the load-bearing heat insulation layer, and the substrate of the load-bearing heat insulation layer.

[0007] Preferably, the high thermal conductivity C / C composite thin layer has both high in-plane thermal conductivity and high out-of-plane thermal conductivity, wherein the high in-plane thermal conductivity is above 300 W·m. -1 ·K -1 -600W·m -1 ·K -1 Between; the out-of-plane high thermal conductivity is between 100 W·m -1 ·K -1 -300W·m -1 ·K -1 between.

[0008] Preferably, the low thermal conductivity C / C honeycomb has low in-plane thermal conductivity and low out-of-plane thermal conductivity, both of which are no greater than 15 W·m. -1 ·K -1 The equivalent density of the low thermal conductivity C / C honeycomb is 0.05-0.5 g / cm³. 3 The low thermal conductivity C / C honeycomb has a compressive strength of 5-15 MPa and a shear strength of 5-10 MPa, and the side length and thickness of the low thermal conductivity C / C honeycomb are adjustable.

[0009] Preferably, the porous thermal insulation material can be completely or partially filled inside the low thermal conductivity C / C honeycomb structure. The porous thermal insulation material is a lightweight porous aerogel material with a porosity greater than 90% and a thermal conductivity less than 0.5 W·m. -1 ·K -1 .

[0010] A method for constructing a honeycomb-filled multifunctional thermal protection structure includes the following steps:

[0011] Step 1: Use 3D modeling software to create a two-scale geometric model;

[0012] Step 2: Establish a high-fidelity dual-scale mathematical model based on the actual usage environment and conditions;

[0013] Step 3: Use finite element software to simulate the heat protection, insulation, and mechanical properties of the honeycomb-filled multifunctional thermal protection structure;

[0014] Step 4: Determine the final design by comprehensively evaluating the heat protection, thermal insulation, mechanical properties, and lightweight level of the honeycomb-filled multifunctional thermal protection structure.

[0015] Preferably, the dual-scale geometric model includes a microscopic model of the thermal protection structure and a macroscopic model of the thermal protection structure. The microscopic model of the thermal protection structure includes a microscopic three-dimensional woven unit cell model supporting the heat dissipation layer and a microscopic plain woven unit cell model supporting the heat insulation layer. The weaving parameters of the microscopic three-dimensional woven unit cell model supporting the heat dissipation layer and the microscopic plain woven unit cell model supporting the heat insulation layer are designable.

[0016] Preferably, the weaving parameters include the warp spacing, weft spacing, connecting yarn spacing, number of warp layers, number of weft layers, and the warp spacing, weft spacing, number of warp layers, and number of weft layers of the heat-insulating layer.

[0017] Preferably, in the macroscopic model of the thermal protection structure, the thickness of the heat dissipation layer is 1-5 mm, the thickness of the heat insulation layer is 20-60 mm, and the side length of the low thermal conductivity C / C honeycomb is 3.5-10 mm.

[0018] Preferably, the high-fidelity dual-scale mathematical model includes a high-temperature thermal convection model, a high-temperature thermal conduction model, a high-temperature thermal radiation model, a cavity thermal radiation model, a material tension / compression model, and a shear model.

[0019] Therefore, the present invention employs the above-mentioned honeycomb-filled multifunctional thermal protection structure and its construction method, which has the following beneficial effects:

[0020] (1) This invention discloses a honeycomb-filled multifunctional thermal protection structure, which consists of a load-bearing heat dissipation layer and a load-bearing heat insulation layer. The load-bearing heat dissipation layer is made of a high thermal conductivity C / C composite material, which can achieve heat dissipation and has excellent mechanical properties and load-bearing capacity. The load-bearing heat insulation layer is a heat insulation layer composed of a lightweight, high-strength, low thermal conductivity C / C honeycomb composite material, which has efficient heat insulation performance and can reduce the overall weight of the structure. The structure as a whole has the functions of heat protection, heat insulation, and load bearing, and has the characteristics of lightweight and multifunctional integrated design.

[0021] (2) The present invention also discloses a method for constructing a honeycomb-filled multifunctional thermal protection structure, which establishes a dual-scale geometric model and a mathematical model, and can design the thermal protection structure according to the usage conditions and requirements, so as to obtain a multifunctional integrated structure with excellent performance such as heat protection, heat insulation and load bearing, thereby reducing resource waste and R&D costs.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the microscopic three-dimensional woven unit cell geometry of the heat dissipation layer according to an embodiment of the present invention;

[0024] Figure 2This is a schematic diagram of the geometric model of the microstructure of the plain weave unit cell of the load-bearing heat insulation layer according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the macroscopic structure of the honeycomb-filled multifunctional thermal protection structure according to an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the composition of the honeycomb wall and filler of the load-bearing heat insulation layer according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the material composition of the honeycomb-filled multifunctional thermal protection structure according to an embodiment of the present invention;

[0028] Figure 6 This is a simulation diagram of the thermal protection effect of the honeycomb-filled multifunctional thermal protection structure according to an embodiment of the present invention;

[0029] Among them, 1. Warp yarns supporting the heat dissipation layer; 2. Weft yarns supporting the heat dissipation layer; 3. Connecting yarns supporting the heat dissipation layer; 4. Matrix supporting the heat dissipation layer; 5. Matrix supporting the heat insulation layer; 6. Heat dissipation layer; 7. Heat insulation layer; 8. Low thermal conductivity C / C honeycomb; 9. Porous heat insulation material; 10. Thin layer of high thermal conductivity C / C composite material; 11. Air; 12. Carbon aerogel; 13. SiO2 aerogel; 14. Warp yarns supporting the heat insulation layer; 15. Weft yarns supporting the heat insulation layer. Detailed Implementation

[0030] Example

[0031] The following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0032] A honeycomb-filled multifunctional thermal protection structure includes a heat dissipation layer 6 and a heat insulation layer 7. Both the heat dissipation layer 6 and the heat insulation layer 7 include macroscopic and microscopic structures, and both the macroscopic and microscopic structures of the heat dissipation layer 6 and the heat insulation layer 7 are designable.

[0033] The heat dissipation layer 6 is made of a thin layer 10 of C / C composite material with excellent mechanical properties and high emissivity and high thermal conductivity. The microstructure of the heat dissipation layer 6 is a three-dimensional braided structure, which includes the warp yarns 1 of the heat dissipation layer, the weft yarns 2 of the heat dissipation layer that intersect with the warp yarns 1, the connecting yarns 3 of the heat dissipation layer that connect the warp yarns 1 and the weft yarns 2, and the substrate 4 of the heat dissipation layer. The three-dimensional braided structure has load-bearing capacity and ablation resistance. The thin layer 10 of C / C composite material with high thermal conductivity has high in-plane thermal conductivity and high out-of-plane thermal conductivity, with the in-plane thermal conductivity being 300 W·m. -1 ·K -1 -600W·m -1 ·K -1 Between; high out-of-plane thermal conductivity of 100 W·m -1 ·K -1 -300W·m -1 ·K -1 between.

[0034] The load-bearing insulation layer 7 is composed of lightweight, high-strength, low-thermal-conductivity C / C honeycomb 8 and porous insulation material 9. The microstructure of the load-bearing insulation layer 7 is a plain weave structure, which includes the load-bearing insulation layer warp yarns 14, the load-bearing insulation layer weft yarns 15 intersecting with the load-bearing insulation layer warp yarns 14, and the load-bearing insulation layer substrate 5. The low-thermal-conductivity C / C honeycomb 8 has low in-plane thermal conductivity and low out-of-plane thermal conductivity, both of which are no greater than 15 W·m. -1 ·K -1 The equivalent density of low thermal conductivity C / C honeycomb 8 is 0.05-0.5 g / cm³. 3 This significantly reduces the weight of the thermal protection system. The low thermal conductivity C / C honeycomb has a compressive strength of 5-15 MPa and a shear strength of 5-10 MPa, and its side length and thickness are adjustable. Its excellent thermal protection and mechanical properties allow it to simultaneously perform both thermal protection and load-bearing functions. The porous insulation material can be completely or partially filled inside the low thermal conductivity C / C honeycomb. This porous insulation material is a lightweight porous aerogel material with a porosity greater than 90% and a thermal conductivity less than 0.5 W·m. -1 ·K -1 The low thermal conductivity C / C honeycomb is tightly integrated with the porous insulation material, and will not detach or slip under ablation and external loads.

[0035] A method for constructing a honeycomb-filled multifunctional thermal protection structure includes the following steps:

[0036] Step 1: Establish a dual-scale geometric model using 3D modeling software. The dual-scale geometric model includes a mesoscopic model and a macroscopic model of the thermal protection structure. The mesoscopic model includes a mesoscopic three-dimensional woven unit cell model supporting the heat dissipation layer and a mesoscopic plain-weave unit cell model supporting the insulation layer. The weaving parameters of both models are designable. These parameters include the warp and weft spacing, connecting yarn spacing, number of warp layers, and number of weft layers for the heat dissipation layer, and the warp and weft spacing, number of warp layers, and number of weft layers for the insulation layer. In the macroscopic model of the thermal protection structure, the thickness of the heat dissipation layer is 1–5 mm, the thickness of the insulation layer is 20–60 mm, and the side length of the low thermal conductivity C / C honeycomb is 3.5–10 mm.

[0037] Step 2: Based on the actual usage environment and conditions, establish a high-fidelity dual-scale mathematical model; the high-fidelity dual-scale mathematical model includes a high-temperature heat convection model, a high-temperature heat conduction model, a high-temperature heat radiation model, a cavity heat radiation model, a material tension and compression model, and a shear model.

[0038] Step 3: Use finite element software to simulate the heat protection, insulation, and mechanical properties of the honeycomb-filled multifunctional thermal protection structure;

[0039] Step 4: Determine the final design by comprehensively evaluating the heat protection, insulation, mechanical properties, and lightweight level of the honeycomb-filled multifunctional thermal protection structure. The comprehensive performance evaluation of the honeycomb-filled multifunctional thermal protection structure assesses whether each of its indicators meets the predetermined design specifications and whether it satisfies the usage conditions.

[0040] Taking the application of a constant temperature to the material surface as an example, a honeycomb-filled multifunctional thermal protection structure is required, constructed using a high thermal conductivity mesophase bitumen-based C / C composite material as the load-bearing heat dissipation layer and a low thermal conductivity chemical vapor deposition C / C composite material as the load-bearing insulation layer. The structure surface is subjected to a constant temperature of 2000℃, requiring that the temperature rise on the back side of the material not exceed 15℃ after 300 seconds of heating, and that the structure's compressive strength reach at least 10 MPa and 5 MPa. The specific process is as follows:

[0041] First, a mesoscopic unit cell model of the thermal protection structure is established, including unit cells supporting the heat dissipation layer, such as... Figure 1 The three-dimensional braided C / C composite unit cell and the load-bearing insulation layer unit cell shown are as follows: Figure 2 The plain-weave C / C composite unit cell shown has the following initial structural parameters: Figure 1 The warp yarn spacing, weft yarn spacing, and connecting yarn spacing are all 1mm. Figure 2 The warp and weft yarn spacing is also 1mm, and then adjusted it iteratively multiple times based on the calculated structure. Additionally, a macroscopic model of the thermal protection structure is established, including two parts such as… Figure 3 These are the honeycomb and filler that support the heat dissipation layer skin and the heat insulation layer, respectively. The structural composition of the honeycomb and filler is as follows: Figure 4 The initial thickness of the heat dissipation layer is 1mm, the honeycomb thickness is 50mm, and the side length is 3.5mm. The established geometric model is then meshed.

[0042] A high-fidelity dual-scale mathematical model was established based on the design requirements, including a high-temperature heat conduction model, a high-temperature heat radiation model, a cavity heat radiation model, a material tension / compression model, and a shear model. Boundary conditions identical to those in the actual usage environment were set.

[0043] By using the finite element method combined with geometric and mathematical models, the material properties of the microstructure, such as thermal conductivity, specific heat capacity, elastic modulus, and Poisson's ratio, are first calculated. These calculation results are then passed as parameters to the macroscopic model, and the macroscopic heat protection, thermal insulation, and mechanical properties of the material are finally calculated.

[0044] Through continuous iterative adjustments, a final design was obtained, with the following parameters: High thermal conductivity C / C load-bearing heat dissipation layer, 5mm thick; warp pitch 1.5mm, weft pitch 1.5mm, connecting yarn pitch 1.5mm; 4 warp layers, 5 weft layers. Low thermal conductivity C / C load-bearing insulation layer honeycomb wall, 1mm warp pitch, 1mm weft pitch, 1 layer. The load-bearing insulation layer is 60mm thick and can be divided into three layers based on its internal filling structure, such as... Figure 5 The materials are 20mm thick air (11), 20mm thick carbon aerogel (12), and 20mm thick SiO2 aerogel (13). When the surface temperature is 2000℃ and heated for 300s, the temperature rise on the back side of the material is 13.21℃. The results are as follows... Figure 6 As shown, the material has a compressive strength of 11.3 MPa and a shear strength of 6.5 MPa, meeting the design requirements.

[0045] Therefore, the present invention adopts the above-mentioned honeycomb-filled multifunctional thermal protection structure and its construction method, using a thin layer of C / C composite material with high thermal conductivity as the heat dissipation layer and C / C honeycomb and porous thermal insulation material with low thermal conductivity as the thermal insulation layer. The structure as a whole has functions such as heat protection, thermal insulation and load bearing, and has the design features of lightweight and multifunctional integration. It promotes the development of aerospace thermal protection materials and provides thermal protection solutions for the next generation of hypersonic vehicles in harsh and complex environments.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A honeycomb-filled multifunctional thermal protection structure, characterized in that: It includes a load-bearing heat dissipation layer and a load-bearing heat insulation layer, both of which include macroscopic and microscopic structures. The heat dissipation layer is made of a thin layer of C / C composite material with high thermal conductivity. The microstructure of the heat dissipation layer is a three-dimensional woven structure. The three-dimensional woven structure includes the warp yarns of the heat dissipation layer, the weft yarns of the heat dissipation layer that are intersected with the warp yarns of the heat dissipation layer, the connecting yarns of the heat dissipation layer that connect the warp yarns and the weft yarns of the heat dissipation layer, and the substrate of the heat dissipation layer. The load-bearing insulation layer is composed of air, low thermal conductivity C / C honeycomb, and porous insulation material. The microstructure of the load-bearing insulation layer is a plain weave structure, which includes the warp yarns of the load-bearing insulation layer, the weft yarns of the load-bearing insulation layer intersecting with the warp yarns of the load-bearing insulation layer, and the substrate of the load-bearing insulation layer.

2. The honeycomb-filled multifunctional thermal protection structure according to claim 1, characterized in that: The high thermal conductivity C / C composite thin layer has both high in-plane and high out-of-plane thermal conductivity, with the in-plane thermal conductivity being around 300 W·m. -1 ·K -1 -600W·m -1 ·K -1 Between; the out-of-plane high thermal conductivity is between 100 W·m -1 ·K -1 -300W·m -1 ·K -1 between.

3. The honeycomb-filled multifunctional thermal protection structure according to claim 1, characterized in that: The low thermal conductivity C / C honeycomb has low in-plane thermal conductivity and low out-of-plane thermal conductivity, both of which are no greater than 15 W·m. -1 ·K -1 The equivalent density of the low thermal conductivity C / C honeycomb is 0.05-0.5 g / cm³. 3 The low thermal conductivity C / C honeycomb has a compressive strength of 5-15 MPa and a shear strength of 5-10 MPa, and the side length and thickness of the low thermal conductivity C / C honeycomb are adjustable.

4. The honeycomb-filled multifunctional thermal protection structure according to claim 1, characterized in that: The porous thermal insulation material can be completely or partially filled inside the low thermal conductivity C / C honeycomb structure. The porous thermal insulation material is a lightweight porous aerogel material with a porosity greater than 90% and a thermal conductivity less than 0.5 W·m. -1 ·K -1 .

5. A method for constructing a honeycomb-filled multifunctional thermal protection structure as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Use 3D modeling software to create a two-scale geometric model; Step 2: Establish a high-fidelity dual-scale mathematical model based on the actual usage environment and conditions; Step 3: Use finite element software to simulate the heat protection, insulation, and mechanical properties of the honeycomb-filled multifunctional thermal protection structure; Step 4: Determine the final design by comprehensively evaluating the heat protection, thermal insulation, mechanical properties, and lightweight level of the honeycomb-filled multifunctional thermal protection structure.

6. The method for constructing a honeycomb-filled multifunctional thermal protection structure according to claim 5, characterized in that: The dual-scale geometric model includes a microscopic model of the thermal protection structure and a macroscopic model of the thermal protection structure. The microscopic model of the thermal protection structure includes a microscopic three-dimensional woven unit cell model supporting the heat dissipation layer and a microscopic plain woven unit cell model supporting the heat insulation layer. The weaving parameters of the microscopic three-dimensional woven unit cell model supporting the heat dissipation layer and the microscopic plain woven unit cell model supporting the heat insulation layer are designable.

7. The method for constructing a honeycomb-filled multifunctional thermal protection structure according to claim 6, characterized in that: The weaving parameters include the warp and weft spacing of the heat dissipation layer, the connecting yarn spacing, the number of warp layers, the number of weft layers, and the warp and weft spacing of the heat insulation layer.

8. The method for constructing a honeycomb-filled multifunctional thermal protection structure according to claim 6, characterized in that: In the macroscopic model of the thermal protection structure, the thickness of the heat dissipation layer is 1-5 mm, the thickness of the heat insulation layer is 20-60 mm, and the side length of the low thermal conductivity C / C honeycomb is 3.5-10 mm.

9. The method for constructing a honeycomb-filled multifunctional thermal protection structure according to claim 5, characterized in that: The high-fidelity dual-scale mathematical model includes a high-temperature heat convection model, a high-temperature heat conduction model, a high-temperature heat radiation model, a cavity heat radiation model, a material tension / compression model, and a shear model.

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