A high-efficiency heat-proof and heat-insulating load-integrated sandwich composite structure

Abstract

The application discloses a kind of high-efficiency heat-proof load integrated sandwich composite structures, including metal outer panel, intermediate sandwich layer and metal inner panel, intermediate sandwich layer includes heat insulation material layer, phase change material layer and core rod, heat insulation material layer is relatively phase change material layer and is outside, core rod passes through heat insulation material layer and phase change material layer, the inner and outer ends of core rod are connected with metal outer panel and metal inner panel respectively.The beneficial effects of the present application are: the orthogonal M-type rod structure design is used in the intermediate sandwich layer, which not only has the force transmission and strain isolation function of the inner and outer layers, but also greatly prolongs the heat conduction path from the outer panel to the inner panel, effectively alleviating the heat short circuit problem, and the phase change material layer is used to absorb the heat leakage of the sandwich layer rod, thereby further improving the heat-proof performance of the sandwich composite structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heat protection, and particularly relates to a sandwich composite structure with efficient heat insulation and load bearing integration. BACKGROUND

[0002] During high-speed flight in the atmosphere or the process of returning to the atmosphere, an aircraft usually faces a serious problem of aerodynamic heating, which requires that the surface structure of the aircraft meets the mechanical bearing conditions and has sufficient heat insulation capacity to minimize the transfer of aerodynamic heat to the interior of the aircraft, so as to ensure the shape of the aircraft, the integrity of the main bearing structure and the normal operation of the equipment in the cabin. Therefore, the outer fuselage panel of the high-speed aircraft needs to be designed into a structure with heat insulation and load bearing integration, i.e. a heat insulation and load bearing integrated structure.

[0003] The sandwich composite structure has high designability of structure-function integration, and is internationally recognized as the most promising heat insulation and load bearing integrated structure. The sandwich composite structure is usually composed of inner and outer panels and an intermediate sandwich layer, wherein the outer panel is located on the side with higher temperature, and the inner panel is located on the side with lower temperature; the inner and outer panels and the intermediate sandwich layer support part determine the strength and stiffness of the structure, and the intermediate sandwich layer cavity part achieves the purpose of heat insulation by filling functional materials. For the sandwich composite structure, a key problem to be solved at present is the heat short circuit problem caused by the intermediate sandwich layer support part. SUMMARY

[0004] The application aims to provide a sandwich composite structure with efficient heat insulation and load bearing integration, which better alleviates the heat short circuit problem of the intermediate sandwich layer support part of the sandwich composite structure.

[0005] The application aims to achieve the above-mentioned purpose by the following technical scheme.

[0006] The sandwich composite structure with efficient heat insulation and load bearing integration comprises a metal outer panel, an intermediate sandwich layer and a metal inner panel, the intermediate sandwich layer comprises a heat insulation material layer, a phase change material layer and a core rod for transferring load and prolonging the heat transfer path, the heat insulation material layer is located outward relative to the phase change material layer, the core rod penetrates through the heat insulation material layer and the phase change material layer, and the inner and outer ends of the core rod are connected with the metal outer panel and the metal inner panel respectively.

[0007] The sandwich composite structure with efficient heat insulation and load bearing integration can be used as an important part of the large-area heat protection system of the fuselage of the high-speed aircraft, and has the functions of heat protection and load bearing.

[0008] Preferably, the metal outer panel, the metal inner panel and the core rod are selected from aluminum alloy, titanium alloy or other high-temperature alloy according to the use temperature.

[0009] Preferably, the thermal insulation material layer can be selected from aerogel, glass / ceramic fiber thermal insulation felt, phenolic-based composite material and the like according to the use requirement.

[0010] Preferably, the phase change material layer is a solid-solid phase change material with high heat storage density, such as polyol, such as 3-propylene glycol, pentaerythritol, or high molecular solid-solid phase change material, such as high-density polyethylene.

[0011] Preferably, the core rod is an orthogonal M-shaped core rod.

[0012] Preferably, the orthogonal M-shaped core rod comprises a plurality of orthogonal M-shaped core rod units, each of which comprises a positive M rod body, a negative M rod body and a connecting rod body, the positive M rod body and the negative M rod body are arranged orthogonally, the middle concave part of the positive M rod body and the middle concave part of the negative M rod body are connected by the connecting rod body, the two foot parts of the positive M rod body are connected with the metal inner panel, and the two foot parts of the negative M rod body are connected with the metal outer panel.

[0013] Preferably, the plurality of orthogonal M-shaped core rod units are arranged in a horizontal and vertical lattice to form an orthogonal M-shaped core rod.

[0014] Preferably, the positive M rod body, the negative M rod body and the connecting rod body are all located in the phase change material layer, and the end of the two foot parts of the negative M rod body penetrates through the thermal insulation material layer and is connected with the metal outer panel.

[0015] The beneficial effects of the present application are as follows: the orthogonal M-shaped rod structure design of the intermediate sandwich layer can not only provide force transmission and strain isolation function of the inner and outer layers, but also greatly prolong the heat conduction path from the outer panel to the inner panel, effectively alleviate the heat short circuit problem, and utilize the phase change material layer to absorb the heat leakage of the sandwich layer rod, thereby further improving the heat protection performance of the sandwich composite structure.

[0016] Specifically, the thermal insulation material layer has a large thermal resistance, so that most of the heat cannot be transmitted from the metal outer panel to the inside. When the heat is transmitted in the orthogonal M-shaped core rod in the form of heat conduction, the heat conduction path is prolonged, on the one hand, the thermal resistance is increased, and on the other hand, the contact area between the core rod and the phase change material layer is increased, the heat diffusion power of the orthogonal M-shaped core rod to the phase change material layer is increased, thereby reducing the heat transmitted to the metal inner panel. Overall, the high-efficiency heat protection and load integrated sandwich composite structure can achieve good heat protection effect, has excellent instantaneous heat shock resistance, high mechanical load reliability, and can effectively solve the structure heat protection problem of high-speed aircraft.

[0017] The foregoing main scheme and each further selected scheme of the present application can be freely combined to form multiple schemes, all of which are the schemes that can be adopted and claimed by the present application; and the present application can also be freely combined between each non-conflicting selected scheme and between each non-conflicting selected scheme and other selected schemes. A person skilled in the art can understand that there are multiple combinations according to the prior art and common knowledge after understanding the schemes of the present application, all of which are the technical schemes claimed by the present application, and are not listed here. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the present application.

[0019] Figure 2 is a structural exploded view of the present application.

[0020] Figure 3 is a heat transfer schematic diagram of the present application.

[0021] Figure 4 is a heat transfer schematic diagram of the orthogonal M-shaped core rod of the present application.

[0022] In the figure: 1-metal outer panel, 2-intermediate core layer, 3-metal inner panel, 21-thermal insulation material layer, 22-phase change material layer, 23-orthogonal M-shaped core rod, 231-orthogonal M-shaped rod body, 232-reverse M-shaped rod body, 233-connection rod body. DETAILED DESCRIPTION

[0023] The following non-limiting examples are used to illustrate the present application.

[0024] Example 1:

[0025] Reference Figures 1-4 As shown in the figure, a high-efficiency heat insulation and load bearing integrated sandwich composite structure includes a metal outer panel 1, an intermediate core layer 2 and a metal inner panel 3. The intermediate core layer 2 includes a thermal insulation material layer 21, a phase change material layer 22 and a core rod for transferring load and extending the heat transfer path. The thermal insulation material layer 21 is relatively outside the phase change material layer 22. The core rod passes through the thermal insulation material layer 21 and the phase change material layer 22. The inner and outer ends of the core rod are connected to the metal outer panel 1 and the metal inner panel 3, respectively.

[0026] According to actual needs and service conditions, the sandwich composite structure can be used as a large-area skin of a high-speed aircraft alone, or can be an important part of a thermal protection system.

[0027] Reference Figure 3As shown, the outer surface of the high-speed aircraft is subjected to severe aerodynamic heating, which results in a temperature gradient along the thickness direction of the surface structure. The thermal insulation layer 21 hinders the transfer of most of the heat from the metal outer panel 1 to the interior with a low thermal conductivity, so that only a part of the heat 1 is transferred to the thermal insulation layer 21, and another part of the heat 2 is directly transferred from the metal outer panel 1 to the core rod connected thereto. If the metal outer panel 1 itself is the aerodynamic heating surface, it can also transfer heat to the external air through thermal radiation.

[0028] Most of the heat 5 transferred in the core rod is absorbed by the phase change material layer 22, and the thermal insulation layer 21 transfers heat 4 to the phase change material layer 22. In addition, there is also a part of heat 3 exchanged between the thermal insulation layer 21 and the core rod. Finally, the phase change material layer 22 and the core rod transfer heat 10 and 9 to the metal inner panel 3.

[0029] The metal outer panel 1 and the metal inner panel 3 need to bear in-plane tensile, compressive, shear loads and out-of-plane bending loads. If the metal outer panel 1 itself is the outer surface, it also directly bears the aerodynamic pressure. The core rod in the intermediate sandwich layer not only connects the metal outer panel 1 and the metal inner panel 3, but also bears the out-of-plane shear and resists the buckling deformation of the panel.

[0030] The metal outer panel 1 needs to bear a large mechanical load at high temperature, and a material with good high-temperature mechanical properties needs to be selected. Preferably, the metal outer panel 1, the metal inner panel 3 and the core rod are made of aluminum alloy, titanium alloy or high-temperature alloy with low thermal expansion coefficient.

[0031] The thermal insulation layer 21 needs to select a thermal insulation material with high temperature resistance and low thermal conductivity. Preferably, the thermal insulation layer 21 is made of aerogel, glass / ceramic fiber thermal insulation felt or phenolic-based composite material.

[0032] The phase change material layer 22 is a solid-solid phase change material with high heat storage density, which can overcome the defects of liquid phase leakage, corrosion and high cost packaging of solid-liquid phase change materials. The solid-solid phase change material can be selected from 3-propylene glycol, pentaerythritol and other polyol-based or high-density polyethylene-based solid-solid phase change materials with large phase change enthalpy, moderate phase change temperature and long service life.

[0033] The core rod that prolongs the heat transfer path is an orthogonal M-type core rod 23, which not only has good load-bearing capacity, but also effectively prolongs the heat transfer path and increases the contact area with the phase change material layer 22. Similarly, the core rod can also be selected in other forms of core support that prolong the heat transfer and dissipation path.

[0034] The orthogonal M-shaped core rod 23 needs to connect the outer metal panel 1 and the inner metal panel 3, therefore its constituent materials require mature welding or additive manufacturing processes; it needs to withstand out-of-plane shear and resist buckling deformation of the panel, so its constituent materials must have good high-temperature mechanical properties, and since it needs to minimize thermal short-circuit problems, its thermal conductivity should be low. The material of the inner metal panel 3 needs to withstand high in-plane loads at relatively low temperatures, so it should have high heat capacity and good mechanical properties.

[0035] The orthogonal M-type core rod 23 includes several orthogonal M-type core rod units, as referenced. Figure 1 As shown, to more clearly demonstrate the details, the smallest repeating unit of the sandwich composite structure is listed. Several orthogonal M-shaped core rods are arranged in a horizontal and vertical lattice to form orthogonal M-shaped core rods 23, and adjacent orthogonal M-shaped core rod units are part of each other.

[0036] refer to Figure 4 As shown, each orthogonal M-shaped core rod unit includes a positive M-shaped rod 231, a negative M-shaped rod 232, and a connecting rod 233. The positive M-shaped rod 231 has its opening facing downwards, and the negative M-shaped rod 232 has its opening facing upwards. The positive M-shaped rod 231 and the negative M-shaped rod 232 are arranged orthogonally. The concave part of the positive M-shaped rod 231 (i.e., the lower middle part of the M-shape) and the concave part of the negative M-shaped rod 232 are connected by the connecting rod 233. The two legs of the positive M-shaped rod 231 are connected to the inner metal panel 3, and the two legs of the negative M-shaped rod 232 are connected to the outer metal panel 1.

[0037] The positive M-shaped rod 231, the negative M-shaped rod 232, and the connecting rod 233 are all located within the phase change material layer 22. Only the two ends of the negative M-shaped rod 232 pass through the heat insulation material layer 21 and connect to the metal outer panel 1. Due to the structure of the orthogonal M-shaped core rod unit, the heat transfer path is extended, and the contact area with the phase change heat-absorbing material is increased, thereby improving the overall thermal insulation efficiency of the composite structure.

[0038] The key point and protection point of this invention is the orthogonal M-shaped core rod structure and its combined use with phase change material. Its function is to: increase the thermal resistance by extending the heat dissipation path, effectively alleviating the thermal short circuit problem; and increase the heat diffusion power of the core rod to the phase change material layer, reducing the heat transferred to the lower panel.

[0039] However, it should be noted that the present invention is not limited to the above-described embodiment. Within the knowledge of those skilled in the art, various changes can be made. For example, the orthogonal M-shaped core rod can be replaced with other core support forms that extend the heat dissipation path. As long as the thermal protection structure includes a core support form that extends the heat dissipation path, it falls within the protection scope of the present invention.

[0040] The foregoing basic example and each of the further selected examples of the present application can be freely combined to form a plurality of embodiments, all of which are employable and claimed embodiments of the present application. In the present application, each of the selected examples can be arbitrarily combined with any of the basic examples and the selected examples.

[0041] The above descriptions are only the preferred embodiment of the application, not intended to limit the application and any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A high-efficiency heat-insulation load-carrying integrated sandwich composite structure comprising a metal outer face sheet (1), an intermediate sandwich core (2) and a metal inner face sheet (3), characterized in that: The intermediate sandwich layer (2) comprises a heat insulation material layer (21), a phase change material layer (22) and a core rod for transferring load and prolonging heat transfer path, the heat insulation material layer (21) is located outside the phase change material layer (22), the core rod passes through the heat insulation material layer (21) and the phase change material layer (22), and the inner and outer ends of the core rod are connected with the metal outer panel (1) and the metal inner panel (3) respectively; The core rod is a right-angle M-shaped core rod (23); The right-angle M-shaped core rod (23) comprises a plurality of right-angle M-shaped core rod units, each right-angle M-shaped core rod unit comprises a right M-shaped rod body (231), an inverse M-shaped rod body (232) and a connecting rod body (233), the right M-shaped rod body (231) and the inverse M-shaped rod body (232) are arranged in a right angle, the middle concave part of the right M-shaped rod body (231) and the middle concave part of the inverse M-shaped rod body (232) are connected through the connecting rod body (233), the two foot parts of the right M-shaped rod body (231) are connected with the metal inner panel (3), and the two foot parts of the inverse M-shaped rod body (232) are connected with the metal outer panel (1).

2. The high-performance thermally protective load-bearing integrated sandwich composite structure of claim 1, wherein: The metal outer panel (1), the metal inner panel (3) and the core rod are made of aluminum alloy, titanium alloy or high-temperature alloy.

3. The high performance thermally protective load bearing integrated sandwich composite structure of claim 1, wherein: The heat insulation material layer (21) is made of aerogel, glass fiber heat insulation felt or phenolic-based composite material.

4. The high performance thermally protective load bearing integrated sandwich composite structure of claim 1, wherein: The phase change material layer (22) is a solid-solid phase change material with high heat storage density.

5. The high performance thermally protective load bearing integrated sandwich composite structure of claim 1, wherein: The phase change material layer (22) is a 3-propylene glycol, pentaerythritol polyol or high-density polyethylene polymer solid-solid phase change material.

6. The high performance thermally protective load bearing integrated sandwich composite structure of claim 1, wherein: The plurality of right-angle M-shaped core rod units are arranged in a horizontal and vertical lattice to form the right-angle M-shaped core rod (23).

7. The high performance thermally protective load bearing integrated sandwich composite structure of claim 1 or 6, wherein: The right M-shaped rod body (231), the inverse M-shaped rod body (232) and the connecting rod body (233) are located in the phase change material layer (22), and the end heads of the two foot parts of the inverse M-shaped rod body (232) pass through the heat insulation material layer (21) and are connected with the metal outer panel (1).

Images