Corrugated plate type integrated thermal protection system based on porous dot matrix composite phase change material

Abstract

The corrugated plate type integrated thermal protection system based on the porous dot matrix composite phase change material comprises an outer plate and an inner plate, the outer plate and the inner plate are arranged in a spaced mode, and a web, a thermal insulation material and the composite phase change material are arranged in a spaced cavity formed by the outer plate and the inner plate; the multiple web plates are arranged in the interval cavities in a penetrating mode and used for forming a supporting structure for connecting the outer plate and the inner plate, and the multiple web plates are inclined to one another; the spacing cavity comprises a first area and a second area, the first area is close to the outer plate and used for containing a heat insulation material, and the second area is close to the inner plate and used for containing a composite phase change material; wherein the composite phase change material is arranged in a porous dot matrix mode, and the porous dot matrix is adopted as a heat conduction reinforcing body. The high heat storage efficiency of the porous dot matrix composite phase change material is utilized to quickly absorb and store heat of the web, so that the heat transferred into the aircraft is reduced, and the system has higher heat insulation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft thermal protection, and in particular to a corrugated plate type integrated thermal protection system based on porous lattice composite phase change material. Background Art

[0002] With the development of near-space hypersonic vehicles, the aerodynamic thermal environment they face is becoming increasingly harsh, thus placing higher demands on future thermal protection systems. Figure 1 The corrugated plate integrated thermal protection system (ITPS) shown in the figure combines load-bearing and heat protection functions, has high structural efficiency, and conforms to the development trend of future thermal protection structures, so it has attracted widespread attention. However, the corrugated plate integrated thermal protection structure has an obvious thermal short-circuit effect, that is, heat is always transferred to the interior of the aircraft through the supporting structure with higher thermal conductivity, which increases the internal temperature and aggravates the temperature non-uniformity. Figure 2 shown. Summary of the invention

[0003] In view of this, the present invention provides a corrugated plate type integrated thermal protection system based on porous lattice composite phase change material to solve the above problems.

[0004] In order to solve the above technical problems, the present invention provides a corrugated plate type integrated thermal protection system based on porous lattice composite phase change material, comprising: The outer plate and the inner plate are arranged at intervals, and the interval cavity formed by the outer plate and the inner plate is provided with a web, a heat insulation material and a composite phase change material; The web is arranged in a penetrating manner in the spacer cavity to form a supporting structure connecting the outer plate and the inner plate. A plurality of webs are arranged and are inclined to each other. The spacer cavity includes a first area and a second area, the first area is close to the outer plate and is used to accommodate the heat insulation material, and the second area is close to the inner plate and is used to accommodate the composite phase change material; wherein, The composite phase change material is formed by combining a phase change material with a porous lattice.

[0005] As an option, the outer plate, the web plate and the inner plate are made of alumina ceramic or a high-temperature alloy.

[0006] As an option, any web is parallel to another web that is spaced apart from each other, and is not parallel to an adjacent web.

[0007] As an optional approach, the web is provided in a corrugated plate structure.

[0008] As an optional method, when the composite phase change material is filled, the Gibson–Ashby lattice is selected as the lattice pattern of the composite phase change material.

[0009] As an optional manner, the first area and the second area are separated by a partition.

[0010] The beneficial effects of the present invention are: The present invention utilizes the high thermal conductivity and large specific surface area of ​​the porous lattice to quickly transfer the heat of the web to the phase change material for storage, so that the temperature in the system can be more evenly distributed and there will be no thermal short circuit problems. The present invention utilizes the high heat storage efficiency of the porous lattice composite phase change material to quickly absorb and store the heat of the web, thereby reducing the amount of heat transferred to the interior of the aircraft, making the system have stronger heat insulation performance. In addition, by designing the geometric parameters of the porous lattice in the composite phase change material to control the heat storage performance of the composite phase change material, the heat insulation performance of the entire system can be finely regulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of an integrated thermal protection system in the prior art; Figure 2 It is a schematic diagram of thermal short circuit effect in the prior art; Figure 3 A schematic diagram of the structure of a corrugated plate-type integrated thermal protection system based on Gibson–Ashby lattice composite phase change material provided in an embodiment of the present invention; Figure 4 Schematic diagram of a porous lattice structure with different geometric parameters provided by an embodiment of the present invention; Figure 5 A schematic diagram of the structure of a corrugated plate-type integrated thermal protection system based on a body-centered cubic lattice composite phase change material provided in an embodiment of the present invention; Figure 6 A schematic diagram of the change of liquid phase ratio in composite phase change materials with different lattice configurations provided by an embodiment of the present invention; Figure 7 A temperature rise curve diagram of the lower surface of the integrated thermal protection system under different lattice structures provided by an embodiment of the present invention; Figure 8 Schematic diagram of temperature distribution of a corrugated plate integrated thermal protection system based on a body-centered cubic lattice composite phase change material at t=300s provided in an embodiment of the present invention.

[0012] Reference numerals and their corresponding relationships: 1-outer plate, 2-inner plate, 3-web plate, 4-thermal insulation material, 51-porous lattice, 52-phase change material. DETAILED DESCRIPTION

[0013] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0014] With the development of near-space hypersonic vehicles, the aerodynamic thermal environment they face is becoming increasingly harsh, thus placing higher demands on future thermal protection systems. Figure 1 The corrugated plate integrated thermal protection system (ITPS) shown in the figure combines load-bearing and heat protection functions, has high structural efficiency, and conforms to the development trend of future thermal protection structures, so it has attracted widespread attention. However, the corrugated plate integrated thermal protection structure has an obvious thermal short-circuit effect, that is, heat is always transferred to the interior of the aircraft through the supporting structure with higher thermal conductivity, which increases the internal temperature and aggravates the temperature non-uniformity. Figure 2 shown.

[0015] Therefore, in this embodiment, in order to solve the thermal short circuit problem of the traditional corrugated plate integrated thermal protection system, a corrugated plate integrated thermal protection system (PCMs-ITPS) based on porous lattice 51 composite phase change material 52 is designed. The system is composed of outer plate 1, web 3, inner plate 2, thermal insulation material 4, porous lattice 51 and phase change material 52. Figure 3 As shown, the outer plate 1 and the inner plate 2 are spaced apart, and the spaced cavity formed therein is provided with a web 3, a heat insulating material 4 and a composite phase change material 52; the web 3 is arranged through the spaced cavity to form a supporting structure connecting the outer plate 1 and the inner plate 2, and a plurality of webs 3 are arranged, and are inclined to each other; the spaced cavity includes a first area and a second area, the first area is close to the outer plate 1, and is used to accommodate the heat insulating material 4, and the second area is close to the inner plate 2, and is used to accommodate the composite phase change material 52; wherein the composite phase change material 52 is arranged in a porous lattice 51. When filling the composite phase change material 52 of this embodiment, the Gibson-Ashby lattice is preferably used as the lattice pattern of the composite phase change material 52. You may also choose the following Figure 4 The other styles described above: wherein any web 3 is parallel to another web 3 spaced apart from each other, and is not parallel to the adjacent web 3; and the web 3 is arranged in a corrugated plate structure.

[0016] In this embodiment, the outer plate 1, the web 3 and the inner plate 2 are generally made of alumina ceramics or high-temperature alloys and are manufactured in an integrated manner by 3D printing. The positions and functions of each component are as follows: Outer plate 1: It is located at the outermost layer of the entire structure, in direct contact with the outside world, and is responsible for resisting external aerodynamic forces / thermal loads. During flight, the external thermal load will directly act on the outer plate 1, and then the outer plate 1 will transfer part of the heat to the external environment by radiation, and the remaining part of the heat will be transferred to the interior of the aircraft through the belly plate 3.

[0017] Web 3: Located between the inner panel 2 and the outer panel 1, and in contact with the heat insulating material 4 and the phase change material 52, it mainly bears the load-bearing function. However, since the thermal conductivity of the web 3 is usually several orders of magnitude higher than that of the heat insulating material 4, the heat of the outer panel 1 is mainly transferred to the interior of the aircraft through the web 3.

[0018] Inner panel 2: It is located in the innermost layer of the entire structure and is in direct contact with the environment inside the aircraft cabin. It is responsible for isolating the phase change material 52 from the environment inside the cabin.

[0019] Heat insulation material 4: located on the side close to the outer panel 1, its main function is to reduce the heat transfer from the outer panel 1 to the inside of the aircraft.

[0020] Composite phase change material 52 based on porous lattice 51: Located near the inner plate 2, its main function is to quickly absorb the heat transferred from the web 3. The pore size of the porous lattice 51 is in the order of millimeters, and has a large specific surface area, which can evenly transfer heat to the phase change material 52. The main function of the phase change material 52 is to store heat using its own latent heat. During the heat storage process, the phase change material 52 will change from solid to liquid.

[0021] Through the above design, when the system faces external heating, the heat is all concentrated on the outer plate 1. At this time, part of the heat is transferred to the outside through radiation, and the remaining heat will be transferred to the web 3 and the insulation material 4. However, since the thermal conductivity of the web 3 is much higher than that of the insulation material 4, the heat is mainly transferred to the interior of the aircraft through the web 3. In the process of heat transfer to the interior, the porous lattice 51 in the composite phase change material 52 will evenly transfer the heat transferred from the web 3 to the phase change material 52 for absorption, thereby greatly reducing the temperature of the inner plate 2 and maintaining good temperature uniformity of the overall structure. Therefore, the temperature of the inner plate 2 can be maintained near the phase change temperature of the phase change material 52 for a long time, thereby ensuring that the ambient temperature in the aircraft cabin is in a suitable temperature range.

[0022] In the above-mentioned design process, the porous lattice 51 composite phase change material 52 is obtained by combining the porous lattice 51 with the phase change material 52. And by adjusting the geometric parameters (lattice configuration, porosity, pore size) of the porous lattice 51, the heat storage performance of the composite phase change material 52 can be changed, thereby affecting the heat insulation performance of the integrated thermal protection system. The PCMs-ITPS scheme proposed in this embodiment has excellent heat insulation effect, can effectively solve the thermal short circuit problem in the integrated thermal protection system, and improve the overall temperature uniformity of the system. More importantly, the PCMs-ITPS scheme can finely control the overall heat insulation performance of the system by adjusting the geometric parameters of the porous lattice 51.

[0023] Specifically, changing the geometric parameters (lattice configuration, porosity, pore size, etc.) of the porous lattice 51 can change the total amount of heat storage and the heat storage efficiency of the composite phase change material 52. Figure 4 Shown are seven common porous matrices 51 having different porosities. Figure 5 This is an optional method that adopts the structural style of this embodiment using a body-centered cubic lattice design.

[0024] Different lattice configurations have different specific surface areas and heat conduction paths, which will lead to significant differences in the heat storage efficiency of the composite phase change material 52. The larger the specific surface area, the faster the heat storage efficiency of the composite phase change material 52. For example, in different lattice configurations with a pore diameter of 6 mm and a porosity of 0.7, under the same heating conditions, the liquid phase rate of the composite phase change material 52 formed by them changes as follows: Figure 6 As shown, the body-centered cubic lattice with the largest specific surface area has the fastest heat storage efficiency.

[0025] Different porosities will result in different material proportions of the porous lattice 51 and the phase change material 52. For example, the smaller the porosity of the porous lattice 51, the greater the proportion of the phase change material 52, and the smaller the proportion of the porous lattice 51, which will increase the total heat storage of the composite phase change material 52, but the heat storage efficiency will be lower.

[0026] The porous lattices 51 with different apertures have different specific surface areas, and the porous lattices 51 also have different obstructions to the natural convection in the liquid phase change material 52. For example, the smaller the aperture, the larger the specific surface area of ​​the porous lattice 51, and the faster the heat storage efficiency of the composite phase change material 52, but the greater the obstruction of the porous lattice 51 to the natural convection of the phase change material 52, the lower the heat storage efficiency of the composite phase change material 52.

[0027] Therefore, in order to solve the problem of how to select the optimal porous lattice 51 as the composite phase change material 52, this embodiment provides the following verification scheme: Please refer again Figure 3-Figure 6 In this embodiment, a PCMs-ITPS solution based on a body-centered cubic lattice is first designed. The overall size of the model is 60 mm in length (L), 18 mm in width (W), and 40 mm in height (H). The model includes an outer plate 1, a web 3, an inner plate 2, a heat-insulating material 4, and a composite phase-change material 52 based on a porous lattice 51. The composite phase-change material 52 based on a porous lattice 51 is composed of a body-centered cubic lattice and a phase-change material 52.

[0028] The thickness of the outer plate 1 is 2 mm. This part is in direct contact with the outside world, and the external mechanical and thermal loads act directly on the outer plate 1. Part of the heat of the outer plate 1 is transferred to the external environment by radiation, and the remaining heat is transferred to the web 3 and the thermal insulation material 4. The web 3 is a traditional corrugated plate structure, connecting the outer plate 1 and the inner plate 2, with a thickness of 1.5 mm, and its main function is to bear. The thermal insulation material 4 is in direct contact with the outer plate 1, with a thickness of 18 mm, and its main function is to prevent the heat of the outer plate 1 from transferring inward. Since the thermal conductivity of the web 3 is much higher than that of the thermal insulation material 4, the heat is mainly transferred inward through the web 3.

[0029] The composite phase change material 52 based on the porous lattice 51 is located near the inner plate 2, has a thickness of 18 mm, and has a high heat storage efficiency. The porous lattice 51 adopts a body-centered cubic lattice with a pore size of 6 mm and a porosity of 0.75, which can quickly and evenly store the heat in the web 3 in the phase change material 52, avoiding the heat transfer to the inner plate 2 causing the temperature in the cabin to rise, and can effectively alleviate the thermal short circuit problem.

[0030] In addition, there is a 0.5 mm partition between the heat insulating material 4 and the phase change material 52, which can not only isolate the heat insulating material 4 from the phase change material 52, but also transfer the heat of the web 3 to the phase change material 52. The thickness of the inner panel 2 is 1.5 mm, and its main function is to isolate the heat protection structure from the aircraft cabin. The materials of the inner and outer panels, the web 3 and the porous lattice 51 are all alumina ceramics, the heat insulating material 4 is aerogel, and the phase change material 52 is paraffin.

[0031] Numerical simulation methods were used to verify the heat transfer characteristics of the PCMs-ITPS scheme. Adiabatic boundary conditions were used on the four sides and the bottom surface of the model. The temperature of the top surface was constant at 373.15 K, while the ambient temperature was 288.15 K. The temperature response of the bottom surface of the model was obtained through numerical simulation and compared with the bottom surface temperature rise curve of the traditional corrugated plate integrated thermal protection system. The results are shown in Figure 2. Figure 7 As shown. The lower surface temperature of the inner plate 2 of the body-centered cubic lattice PCMs-ITPS model is significantly reduced. For example, at t=500 s, the lower surface temperature of the inner plate 2 of the body-centered cubic lattice PCMs-ITPS is 40 K lower than that of the traditional corrugated plate integrated thermal protection system. And this model effectively alleviates the thermal short circuit problem of the corrugated plate integrated thermal protection system. For example, at t=300 s, the temperature distribution of the model is as follows Figure 8 As shown, the temperature shows an obvious hierarchical distribution from the outside to the inside, and there is no thermal short circuit phenomenon.

[0032] Finally, in order to verify the feasibility of changing the thermal protection performance of PCMs-ITPS by changing the geometric parameters of the porous lattice 51, the porous lattice 51 was changed to a Gibson–Ashby lattice with a porosity of 0.9, and the pore size was kept unchanged. The schematic diagram of the structure is shown in FIG. Figure 3 The temperature rise curve of the lower surface of this model is shown as Figure 7 As shown in the figure, the results show that the temperature control time of this model is prolonged, which is due to the increase in porosity, resulting in an increase in the total amount of heat storage. At the same time, the temperature of the lower surface of the model is also reduced. For example, at t=500 s, the temperature of the lower surface of the model is reduced by 3 K. This is because the change in the lattice configuration reduces the contact area with the inner plate 2, so the heat transferred to the inside of the model through the porous lattice 51 is reduced.

[0033] Through the above verification, this embodiment uses Gibson-Ashby lattice as the porous lattice 51 structure of the composite phase change material 52 to solve the problem of thermal short circuit in the corrugated plate integrated thermal protection system. And not only provides a more preferred solution, but also provides an idea of ​​finely designing the PCMs-ITPS anti-insulation performance by adjusting the geometric parameters of the porous lattice 51 in the composite phase change material 52. Let this embodiment use the high heat storage efficiency of the porous lattice 51 composite phase change material 52 to quickly absorb and store the heat of the web 3, so that the heat transferred to the interior of the aircraft is reduced, so that the system has stronger anti-insulation performance. And provide a new idea, by designing the geometric parameters of the porous lattice 51 in the composite phase change material 52 to control the heat storage performance of the composite phase change material 52, so as to finely regulate the anti-insulation performance of the entire system.

[0034] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A corrugated plate integrated thermal protection system based on porous lattice composite phase change materials, characterized in that: include: The outer plate and the inner plate are arranged at an interval, and a web, a heat insulating material and a composite phase change material are arranged in the interval cavity formed by the outer plate and the inner plate; The web is arranged in the spacer cavity to form a supporting structure connecting the outer plate and the inner plate. A plurality of webs are arranged and are inclined to each other. The spacer cavity includes a first area and a second area, the first area is close to the outer plate and is used to accommodate the heat insulation material, and the second area is close to the inner plate and is used to accommodate the composite phase change material; wherein, The composite phase change material is composed of a phase change material and a porous lattice.

2. The corrugated plate type integrated thermal protection system based on porous lattice composite phase change material according to claim 1 is characterized in that: The outer plate, the web plate and the inner plate are made of alumina ceramics or high-temperature alloy.

3. The corrugated plate integrated thermal protection system based on porous lattice composite phase change material according to claim 1 is characterized in that: Any of the webs is parallel to another web that is spaced apart from each other, and is not parallel to an adjacent web.

4. The corrugated plate type integrated thermal protection system based on porous lattice composite phase change material according to claim 3 is characterized in that: The web is arranged in a corrugated plate structure.

5. The corrugated plate type integrated thermal protection system based on porous lattice composite phase change material according to claim 1, characterized in that: When the composite phase change material is filled, the Gibson-Ashby lattice is selected as the lattice pattern of the composite phase change material.

6. The corrugated plate type integrated thermal protection system based on porous lattice composite phase change material according to claim 1, characterized in that: The first area is separated from the second area by a partition.

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