JP2023553767A - Heat shield structure and its manufacturing method - Google Patents

Abstract

[Abstract] The present invention provides a heat shield structure and a method for manufacturing the same, the heat shield structure including a heat insulating layer, a cavity layer, and a skin disposed in sequence, the heat insulating layer being an internal cabin of an air vehicle. The insulation layer includes a porous insulation structure, a temperature-sensitive hydrogel provided in the porous insulation structure, and a cooling working substance adsorbed in the temperature-sensitive hydrogel. When the heat shield structure does not perform heat shielding, the temperature sensitive hydrogel is in a swollen state, and the cooling substance is adsorbed in the form of a solid phase into the temperature sensitive hydrogel, and the heat shield structure When shielding is performed, the temperature-sensitive hydrogel absorbs the heat radiated inward from the skin and cavity layer, becomes a de-swelled state, and changes the existence form of the cooling substance from the solid phase to the liquid phase and gas phase sequentially. Then, the cooling working material in the gas phase is released into the cavity layer and then discharged. The heat shield structure provided by the present invention has excellent heat shield performance. [Selection diagram] Figure 1

Description

TECHNICAL FIELD The present invention relates to the field of heat shield technology, and more particularly to a heat shield structure and a method for manufacturing the same.

At present, high-speed flying vehicle technology has greatly improved humanity's abilities in space exploration, space entry, space control, and space utilization, and has special military strategic significance and important scientific value. However, whether it is a projectile approaching space hypersonic speeds or a spacecraft entering or returning for space exploration, when re-entering or flying at hypersonic speeds (>5 Mach) in the atmosphere, , After passing through the harsh aerodynamic heating environment, the flying object or spacecraft faces the key technical challenge of "new thermal barrier", so we develop the heat shield mechanism and guide the design and manufacturing of the flying object's heat shield system. This is an effective route to solving this difficult problem.

The heat shielding mechanism is a special mechanism dedicated to projectile heat shielding, and is a mechanism that includes a heat shielding mechanism (eg, based on material attributes, physicochemical effects, or structural principles, etc.), a system configuration structure, and its operating principle. Currently, the heat shield mechanisms employed by hypersonic vehicles in active duty or test flight (e.g., X-15, X-37B, Apollo Return Ship, (e.g. heat sinks, insulation structures), semi-passive types (e.g. ablation, heat pipes) and active types (e.g. working substances, cooling flows). These conventional heat shielding mechanisms have a common feature: they all accomplish their heat shielding function by depleting, dispersing, blocking, or counteracting the material or structure itself.

However, in the future, spacecraft approaching space hypersonic speeds will develop toward high velocity regions, wide spatial regions, long flight times, and reusability, and in the future, spacecraft will move toward the Moon, Mars, Jupiter, the Sun, etc. As the multiple critical deep space exploration missions of It will not be possible to satisfy the heat shield requirements of hypersonic flying vehicles.

Embodiments of the present invention provide a heat shield structure and method for manufacturing the same, and provide a heat shield structure that can meet the heat shield requirements of future hypersonic vehicles.

According to a first aspect, the invention provides:
an insulating layer, a cavity layer, and a skin disposed in sequence, the insulating layer being disposed on an exterior surface of an interior cabin of the vehicle;
The heat insulating layer includes a porous heat insulating structure, a temperature sensitive hydrogel provided in the porous heat insulating structure, and a cooling substance adsorbed in the temperature sensitive hydrogel,
When the heat shielding structure does not provide heat shielding, the temperature sensitive hydrogel is in a swollen state and the cooling agent is adsorbed into the temperature sensitive hydrogel in the form of a solid phase;
When the heat shielding structure performs heat shielding, the temperature-sensitive hydrogel absorbs the heat radiated inward from the skin and the hollow layer, becomes a de-swelled state, and converts the cooling working material into a solid phase. Provided is a heat shield structure in which the cooling substance in the vapor phase is sequentially transformed into a liquid phase and a gas phase, and is discharged after being discharged into the cavity layer.

The purpose of the present invention is to develop a heat shield mechanism in which active and passive types work together to meet the demand for a heat shield structure that can be reused over a long period of time required for the next generation of hypersonic flying vehicles. Specifically, it is to realize a heat shield by a heat shield mechanism that increases the cooperation between heat radiation that radiates inward (passive type) and heat radiation that transitions from solid phase to aqueous phase (active type). It is.

Passive type: The conventional heat shield structure mainly radiates to the outside through the external skin (outside) to achieve heat dissipation, and the present invention increases the cavity layer between the skin and the insulation material in addition to external radiation. By doing so, it is possible to dissipate heat inside the skin, and by modifying the surface layer inside the skin, the emissivity inside the skin can be significantly improved, reaching a maximum of 0.9. In addition to the heat shield, one increases the internal radiation heat dissipation and realizes the purpose of improving the heat shield efficiency of the heat shield structure.

Active type: Water has the highest latent heat of phase transition and is the most suitable cooling substance for cooling by phase transition. However, due to the fluidity and storability of water, water is used for sealing, storage, corrosion resistance, etc. in heat shield structures. A series of complex auxiliary structures need to be placed, and it cannot be applied to the actual project heat shield structure. In order to solve this problem, the present invention adopts solid phase water instead of conventional liquid phase water, and converts liquid phase water into small particles of solid phase water using temperature-sensitive hydrogel and inorganic-organic mounting technology. Transfer and fill the lower layer of inorganic insulation material, and select alumina porous insulation material by comparison. Solid phase water particles are immobilized in the microwells of the porous medium by chemical grafting. The solid phase hydrogel can be tightly bonded to the porous insulation after filling is complete. After the temperature inside the cavity increases due to radiation, the solid phase water is slowly released to form liquid phase water, and after the liquid phase water receives heat, it immediately evaporates as water vapor, and this liquid-vapor phase Removes heat through metastasis.

The mutual cooperation between internal radiation heat dissipation (passive type) and solid-water phase transition heat dissipation (active type) can greatly improve the heat shielding ability of the heat shield structure. Here, the thickness of the cavity between the skin and the porous medium, the distribution and pore size of the microwells inside the porous medium, and the content of solid water can be designed and adjusted according to the requirements of the heat shield. Can be done.

The heat shield mechanism of the present invention is an active-passive cooperative heat shield mechanism, which not only fully exerts external radiation heat dissipation, but also increases the internal radiation heat dissipation phase, and more importantly, solid phase water phase change heat dissipation. The heat dissipation is 30 to 50 times that of radiant heat dissipation, and its heat shielding effect is superior to other single active or passive types such as ceramic-based insulated heat shields, transpiration cooling, and film cooling. Superior to type heat shield equipment and structure.

The heat shield structure based on the active/passive cooperative heat shield mechanism of the present invention can be applied to heat shield structures such as the leading edge of the wing and nose cone of hypersonic flying vehicles, and can be applied to heat shield structures such as the leading edge of the wing and nose cone of hypersonic flying vehicles. It can also be applied to areas and can withstand a heat load of 100-10 MW/m ² and for 30 minutes.

According to different heat load conditions, the thickness of the heat shield structure provided by the present invention is 10-100 mm, the temperature of the back wall of the heat shield structure provided by the present invention is less than 100 °C, and the temperature provided by the present invention is The heat shield structure has the characteristics of integrating heat shield, insulation and loading.

Preferably, the heat shield structure further includes a screw and a nut, and the heat insulating layer and the skin are fixed on the outer surface of the interior cabin of the aircraft by engagement of the screw and the nut.

Preferably, both the screw and the nut are made from alumina ceramic.

Preferably, the porous insulation structure is made from alumina ceramic.

Preferably, the heat shield structure according to any of the first aspects above, wherein the cooling working substance includes water.

According to a second aspect, the invention provides a method of manufacturing a heat shield structure, the method comprising:
disposing a temperature-sensitive hydrogel and a porous insulation structure in a container containing a cooling working substance, and allowing the temperature-sensitive hydrogel to enter the porous insulation structure, the temperature of the cooling working substance increasing the temperature of the cooling working substance; is a first predetermined temperature, and the temperature-sensitive hydrogel is in a de-swelled state under the first predetermined temperature;
lowering the temperature of the cooling substance to a second predetermined temperature and adsorbing the cooling substance in the form of a solid phase into the temperature-sensitive hydrogel to obtain a heat insulating layer, the temperature-sensitive hydrogel is in a swollen state at a predetermined temperature;
fixing the heat insulating layer and the skin, and installing a hollow layer between the heat insulating layer and the skin to form a heat shield structure, the heat insulating layer being provided on an outer surface of the interior cabin of the aircraft; Includes steps and steps to be performed.

The purpose of the present invention is to provide a heat shield mechanism in which active and passive types work together to meet the demand for a heat shield structure that can be reused over a long period of time required for next-generation hypersonic flying vehicles. By realizing a heat shield using a heat shield mechanism that increases the cooperation between heat radiation that radiates inward (passive type) and heat radiation that transitions from the solid phase to the aqueous phase (active type). be.

Passive type: The conventional heat shield structure mainly radiates to the outside through the external skin (outside) to achieve heat dissipation, and the present invention increases the cavity layer between the skin and the insulation material in addition to external radiation. By doing so, it is possible to dissipate heat inside the skin, and by modifying the surface layer inside the skin, the emissivity inside the skin can be significantly improved, reaching a maximum of 0.9. In addition to the heat shield, one increases the internal radiation heat dissipation and realizes the purpose of improving the heat shield efficiency of the heat shield structure.

Active type: Water has the highest latent heat of phase transition and is the most suitable cooling substance for cooling by phase transition. However, due to the fluidity and storability of water, water is used for sealing, storage, corrosion resistance, etc. in heat shield structures. A series of complex auxiliary structures need to be placed, and it cannot be applied to the actual project heat shield structure. In order to solve this problem, the present invention adopts solid phase water instead of conventional liquid phase water, and converts liquid phase water into small particles of solid phase water using temperature-sensitive hydrogel and inorganic-organic mounting technology. Transfer and fill the lower layer of inorganic insulation material, and select alumina porous insulation material by comparison. Solid phase water particles are immobilized in the microwells of the porous medium by chemical grafting. The solid phase hydrogel can be tightly bonded to the porous insulation after filling is complete. After the temperature inside the cavity increases due to radiation, the solid phase water forms liquid phase water by slow release, and the liquid phase water immediately evaporates into water vapor after receiving heat, and further due to this liquid-vapor phase transition. Take away heat.

The mutual cooperation between internal radiation heat dissipation (passive type) and solid-water phase transition heat dissipation (active type) can greatly improve the heat shielding ability of the heat shield structure. Here, the thickness of the cavity between the skin and the porous medium, the distribution and pore size of the microwells inside the porous medium, and the content of solid water can be designed and adjusted according to the requirements of the heat shield. Can be done.

The heat shield mechanism of the present invention is an active-passive cooperative heat shield mechanism, which not only fully exerts external radiation heat dissipation, but also increases the internal radiation heat dissipation phase, and more importantly, solid phase water phase change heat dissipation. The heat dissipation is 30 to 50 times that of radiant heat dissipation, and its heat shielding effect is superior to other single active or passive types such as ceramic-based insulated heat shields, transpiration cooling, and film cooling. Superior to type heat shield equipment and structure.

The heat shield structure based on the active/passive cooperative heat shield mechanism of the present invention can be applied to heat shield structures such as the leading edge of the wing and nose cone of hypersonic flying vehicles, and can be applied to heat shield structures such as the leading edge of the wing and nose cone of hypersonic flying vehicles. It can also be applied to areas and can withstand a heat load of 100-10 MW/m ² and for 30 minutes.

According to different heat load conditions, the thickness of the heat shield structure provided by the present invention is 10-100 mm, the temperature of the back wall of the heat shield structure provided by the present invention is less than 100 °C, and the temperature provided by the present invention is The heat shield structure has the characteristics of integrating heat shield, insulation and loading.

Preferably, the step of fixing the thermal insulation layer and the skin comprises:
fixing the insulation layer and the skin by engagement with screws and nuts.

Preferably, both the screw and the nut are made from alumina ceramic.

Preferably, the porous insulation structure is made from alumina ceramic.

Preferably, in the method for manufacturing a heat shield structure according to any of the second aspects, the cooling substance contains water.

The present invention has at least the following beneficial effects compared to the prior art.

Excellent heat shield performance is provided by providing a heat shield structure including a heat insulating layer, a cavity layer, and a skin on the outer surface of a cabin inside a flying object.

The skin and cavity in the heat shield structure have a passive heat shield function, and the passive heat shield mechanism absorbs external heat by the skin, raises the temperature, and then uses heat radiation to absorb the absorbed heat. It is to release some of it. Here, there are two routes of skin heat radiation: one is external radiation emitted to the external environment of the skin, and the other is internal radiation emitted to the cavity. By providing a hollow layer, the present invention allows the skin to radiate heat to the outside while also dissipating inward heat to the hollow layer, thereby providing one inward radiation route in addition to the conventional heat shield. , and further improved the heat shield efficiency of the passive heat shield.

The insulation layer in the heat shield structure includes a porous insulation structure, a temperature-sensitive hydrogel provided in the porous insulation structure, and a cooling agent adsorbed in the temperature-sensitive hydrogel. The voids in the porous insulation structure can accommodate a temperature-sensitive hydrogel that can absorb a cooling working substance in a liquid phase and transfer it to a solid phase.

The thermal insulation layer and the cavity in the heat shield structure provide an active heat shield function. When the heat shield structure performs heat shielding, the temperature-sensitive hydrogel absorbs the heat radiated inward from the skin and cavity layer, becomes a de-swelled state, and changes the existence form of the cooling agent from the solid phase to the liquid phase. and transforms into a gas phase, and releases the cooling working substance in the gas phase into the cavity layer and then discharges it. When the heat insulating layer contains a temperature-sensitive hydrogel and the temperature of the heat-insulating layer is higher than the lower critical solution temperature (LCST) of the temperature-sensitive hydrogel, the temperature-sensitive hydrogel therein exhibits a swollen state, and the cooling process is performed. It absorbs the substance and transforms it into a solid phase to obtain a heat insulating layer, and in the process of using the heat shield structure, the use environment temperature is higher than the lower critical solution temperature (LCST) of the temperature-sensitive hydrogel. , the temperature-sensitive hydrogel absorbs heat and exhibits a de-swelling state, transferring the cooling substance from the solid phase to the liquid phase, and then the cooling substance in the liquid phase continues to absorb heat and further transforms into the gas phase. It metastasizes and is ejected into the cavity where it is discharged, thereby providing an excellent heat shielding function.

Additionally, the heat shield structure provided by the present invention can be used repeatedly. The temperature-sensitive hydrogel in the heat insulating layer has the property of reversibly swelling and de-swelling in response to changes in environmental temperature, making it possible to repeatedly use the heat shield structure. After use, the heat shield structure recovers its excellent heat shield performance by cooling the temperature and replenishing the cooling substance to swell the temperature-sensitive hydrogel therein and absorb the cooling substance.

In order to explain the technical solutions in the embodiments of the present invention or the prior art more clearly, the drawings that need to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious that the following: The described drawings are some embodiments of the invention, and a person skilled in the art can further derive other drawings from these drawings without any creative effort.

FIG. 1 is a schematic diagram of the principle of a heat shield structure provided by an embodiment of the present invention. FIG. 2 is a flowchart of a method for manufacturing a heat shield structure provided by an embodiment of the present invention. FIG. 3(a) is a perspective view of a heat shield structure provided by an embodiment of the present invention. FIG. 3(b) is a local cross-sectional view of a heat shield structure provided by an embodiment of the present invention. FIG. 4 is a comparison diagram of the heat shield effects of the heat shield structure provided by Example 1 of the present invention and the heat shield structure provided by Comparative Example 1. In the figure, 1: skin, 2: cavity layer, 3: heat insulation layer, 4: under plate, 5: screw, 6: nut.

In order to make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be explained clearly and completely with reference to the drawings in the embodiments of the present invention. It is clear that the described embodiments are some, but not all, embodiments of the invention and that a person skilled in the art could obtain them without creative effort based on the embodiments of the invention. All other embodiments mentioned above fall within the protection scope of the present invention.

As shown in FIGS. 1, 3(a) and 3(b), the present invention provides a heat shield structure, which includes a heat insulating layer 3 provided in sequence, a cavity layer 2, a skin 1; a heat insulating layer 3 is provided on the underplate 4;
The heat insulating layer 3 includes a porous heat insulating structure, a temperature sensitive hydrogel provided in the porous heat insulating structure, and a cooling substance adsorbed in the temperature sensitive hydrogel,
When the heat shielding structure does not perform heat shielding, the temperature-sensitive hydrogel is in a swollen state and the cooling working substance is adsorbed into the temperature-sensitive hydrogel in the form of a solid phase;
When the heat shield structure performs heat shielding, the temperature-sensitive hydrogel absorbs the heat radiated inward from the skin 1 and the cavity layer 2, becomes a de-swollen state, and changes the existence form of the cooling substance from the solid phase to the solid phase. It transforms into a liquid phase and a gas phase, and releases the cooling working substance in the gas phase into the cavity layer 2 and then discharges it.

Note that the underplate 4 is a part of the outer surface of the internal cabin of the flying object, and is made of aluminum alloy as a commonly used material.

In the present invention, by installing a heat shield structure including a heat insulating layer 3, a cavity layer 2, and a skin 1 on an underplate 4, excellent heat shield performance is achieved.

The skin 1 and the cavity in the heat shield structure have a passive heat shield function, and the passive heat shield mechanism is such that after the skin 1 absorbs external heat and raises its temperature, the skin 1 absorbs it by heat radiation. The idea is to release some of the heat. Here, there are two routes by which the skin 1 radiates heat: one is external radiation, in which the skin 1 emits heat to the external environment, and the other is internal radiation, in which the skin 1 emits heat to the cavity. . By installing the hollow layer 2, the present invention allows the skin 1 to radiate heat to the outside and at the same time radiate heat to the inside to the hollow layer 2, thereby providing a single internal radiation in addition to the conventional heat shield. The number of routes has been increased, and the heat shield efficiency of the passive heat shield has been further improved.

The heat insulating layer 3 in the heat shield structure includes a porous heat insulating structure, a temperature sensitive hydrogel provided in the porous heat insulating structure, and a cooling substance adsorbed in the temperature sensitive hydrogel. The voids in the porous insulation structure can accommodate a temperature-sensitive hydrogel that can absorb a cooling working substance in a liquid phase and transfer it to a solid phase.

The heat insulating layer 3 and the cavity in the heat shield structure provide an active heat shield function. When the heat shield structure performs heat shielding, the temperature-sensitive hydrogel absorbs the heat radiated inward from the skin 1 and the cavity layer 2, becomes a de-swollen state, and changes the existence form of the cooling substance from the solid phase to the solid phase. It transforms into a liquid phase and a gas phase, and discharges the cooling working substance in the gas phase into the cavity layer 2 and then discharges it. When the heat insulating layer 3 contains a temperature-sensitive hydrogel, and the temperature of the heat-insulating layer 3 is lower than the lower critical melting temperature (LCST) of the temperature-sensitive hydrogel, the temperature-sensitive hydrogel therein exhibits a swollen state, It absorbs the cooling substance and transforms it into a solid phase to obtain the heat insulation layer 3, and in the process of using the heat shield structure, the operating environment temperature is higher than the lower critical solution temperature (LCST) of the temperature-sensitive hydrogel. , At this time, the temperature-sensitive hydrogel absorbs heat and exhibits a de-swelling state, transferring the cooling substance from the solid phase to the liquid phase, and then the cooling substance in the liquid phase continues to absorb heat and further It transforms into a gas phase and is discharged into the cavity, thereby providing an excellent heat shielding function.

Additionally, the heat shield structure provided by the present invention can be used repeatedly. Due to the property of the temperature-sensitive hydrogel in the heat insulating layer 3 that undergoes reversible swelling and de-swelling in response to changes in environmental temperature, the heat shield structure can be used repeatedly. After use, the heat shield structure can swell the temperature-sensitive hydrogel therein and absorb the cooling substance by cooling the temperature and replenishing the cooling substance, thereby restoring the excellent heat shielding performance. . In the present invention, the heat shield structure achieves excellent heat shield performance through an active-passive cooperative heat shield mechanism. After fully demonstrating external radiation heat dissipation, internal radiation heat dissipation (passive heat shield) is increased, and in addition to this, phase change heat dissipation of solid phase water (active heat shield) is increased, and the heat dissipation is This is 30 to 50 times the external radiation heat dissipation. The heat shield structure provided by the present invention can reduce the temperature of the outer surface of the cabin of the hypersonic vehicle to less than 100°C in an aerodynamic heating environment, and the heat shielding effect is clearly demonstrated by the ceramic-based heat insulation type. It is superior to other single active or passive heat shielding mechanisms such as shielding, translation cooling and film cooling.

In addition, during the de-swelling process of the temperature-sensitive hydrogel in the heat insulating layer 3, the cooling substance continues to absorb heat through the phase transition process of solid phase, liquid phase, and gas phase. - Due to the existence of a gas phase balance, the temperature of the insulation layer 3 is maintained below the boiling point temperature of the cooling working substance until the solid phase cooling working substance is exhausted and the effect of the active heat shielding mechanism disappears.

In the present invention, the time of the active heat shielding mechanism can be adjusted by the pore size of the porous insulation structure, the pore distribution, the controlled release rate of water of the temperature-sensitive hydrogel, and the mass of the cooling agent.

In addition, the cooling material selected by the conventional active heat shield structure is in a liquid phase, and since the liquid phase cooling material has fluidity, it must be sealed, stored, and corrosion-resistant in order to be left in the heat shield structure. It is necessary to install a series of complex auxiliary structures, such as, and is difficult to apply in actual heat shield structures. In order to solve this problem, the present invention adds a temperature-sensitive hydrogel to the heat insulation layer 3, since the temperature-sensitive hydrogel can absorb the cooling working substance and transfer it to the solid phase. , it is avoided to provide the heat shield structure with auxiliary structures for storing cooling working substances in liquid phase. In addition to this, the active heat shield mechanism in the heat shield structure of the present invention is completely automatically triggered by temperature change, absorbs heat through the phase transition of the cooling working substance to realize heat shield, and the whole process No sensors and control devices are required.

The heat shield structure provided by the present invention can be applied to parts such as the leading edge of the wing and nose cone of a hypersonic flying vehicle, and can also be applied to a large area of the wind blowing surface, and can generate up to 100 kW/ It can withstand a heat load of m ² to 10 MW/m ² and the loading time can reach up to 30 min. Here, the loading time is the effective time of the active heat shield mechanism.

According to some preferred embodiments, the heat shield structure further includes screws 5 and nuts 6, and the insulation layer 3 and the skin 1 are fixed on the underplate 4 by engagement of the screws 5 and nuts 6. ing.

According to some preferred embodiments, both screw 5 and nut 6 are made from alumina ceramic.

According to some preferred embodiments, the porous insulation structure is made from alumina ceramic.

As shown in FIGS. 3(a) and 3(b), the heat shield structure employs a method in which screws 5 and nuts 6 are engaged to integrate the skin 1, the heat insulating layer 3, and the underplate 4. The nuts 6 can be fixed on both sides of the skin 1, retaining the hollow layer 2 between the insulation layer 3 and the skin 1.

In the present invention, a high temperature alloy plate is used as the skin 1, and an alumina ceramic material is used as the porous heat insulating structure, the screws 5 and the nuts 6, and the alumina ceramic material has excellent heat insulation properties. Alumina ceramic materials have a lower unit cost and a more uniform void distribution compared to other porous insulation materials (eg, zirconia ceramic materials).

According to some preferred embodiments, in the heat shield structure of any of the first aspects above, the cooling working substance comprises water.

It should be noted that water is selected as the optimal cooling working material for cooling by phase transition, since the latent heat of change of the water phase is the highest.

As shown in FIG. 2, the present invention further includes a method of manufacturing a heat shield structure, the method comprising:
disposing the temperature-sensitive hydrogel and the porous insulation structure in a container containing a cooling material, and advancing the temperature-sensitive hydrogel into the porous insulation structure such that the temperature of the cooling material reaches a first temperature; 1, and the temperature-sensitive hydrogel is in a de-swollen state under the first predetermined temperature;
lowering the temperature of the cooling material to a second predetermined temperature and adsorbing the cooling material in the form of a solid phase into the temperature-sensitive hydrogel to obtain a heat insulating layer, the step of: lowering the temperature of the cooling material to a second predetermined temperature; a step in which the temperature-sensitive hydrogel is in a swollen state;
fixing the heat insulating layer and the skin and installing a hollow layer between the heat insulating layer and the skin to form a heat shield structure, the heat insulating layer being provided on the underplate; include.
Note that the first predetermined temperature is slightly higher than the LCST (lower critical melting temperature of the temperature-sensitive hydrogel in the heat insulating layer), and the second predetermined temperature is lower than the LCST. When the temperature of the temperature-sensitive hydrogel is higher than LCST, it exhibits a de-swollen state, and at this time, there is no water inside it, and when the temperature of the temperature-sensitive hydrogel is lower than LCST, it exhibits a swollen state and liquid phase water can be absorbed to form solid phase water within it.

In the present invention, when the cooling material is at the first predetermined temperature, the temperature-sensitive hydrogel in the container is in a liquid phase decomposition swelling state, and at this time, the temperature-sensitive hydrogel is in the voids inside the porous insulation structure. The temperature-sensitive hydrogel macromolecules are bonded to the inner walls of the voids of the porous insulation structure by a grafting method.

In the present invention, when the temperature of the cooling material decreases to a second predetermined temperature, the temperature-sensitive hydrogel in the voids of the porous heat-insulating structure exhibits a swollen state during the cooling process, and a large amount of the high polymer of the hydrophilic mesh structure is formed. When the temperature-sensitive hydrogel absorbs distilled water and swells, and as the temperature decreases, the rate of swelling increases until a second predetermined temperature is reached in the container, the temperature-sensitive hydrogel reaches a swelling balance and the thermal insulation layer get. By lowering the temperature inside the container and causing the temperature-sensitive hydrogel in the porous insulating structure to absorb water and swell, the liquid phase water in the container is converted to solid phase water, and the solid phase water is converted into bound water. and is present in the temperature-sensitive hydrogel in the form of free water.

The heat shield structure provided by the present invention has a thickness of 10 to 100 mm (thickness includes the underplate) and has integrated functions of heat shield, heat insulation, and loading.

In addition, the manufacturing method provided by the present invention has a simple structure, low cost, convenient installation, and strong designability, and the thickness of the insulation layer can be adjusted according to the flight time and the heat load of the flight track. By designing the microfluidic path and distribution and mass of the cooling working material, the demands of different flight missions can be met.

According to some preferred embodiments, securing the insulation layer and the skin comprises:
fixing the insulation layer and the skin through engagement with screws and nuts;

According to some preferred embodiments, both the screw and nut are made from alumina ceramic.

According to some preferred embodiments, the porous insulation structure is made from alumina ceramic.

As shown in Fig. 3, the heat shield structure adopts a method of engaging screws and nuts to integrally fix the skin, the heat insulating layer, and the underplate. is fixed on both sides of the insulation layer and retains a hollow layer between the insulation layer and the skin.

In the present invention, a high temperature alloy plate is used as the skin, and an alumina ceramic material is used as the porous heat insulation structure and the screws and nuts, and the alumina ceramic material has excellent heat insulation properties. Alumina ceramic materials have a lower unit cost and a more uniform void distribution compared to other porous insulation materials (eg, zirconia ceramic materials).

According to some preferred embodiments, in any of the above methods of manufacturing a heat shield structure, the cooling working substance includes water.

It should be noted that water is selected as the optimal cooling working material for cooling by phase transition, since the latent heat of phase transition of water is the highest.

In order to more clearly explain the technical solutions and advantages of the present invention, the heat shield structure and its manufacturing method will be described in detail below with some embodiments.

Example 1
The temperature-sensitive hydrogel and the 100 mm x 100 mm x 8 mm porous alumina ceramic plate are placed in a container containing distilled water, and the temperature-sensitive hydrogel enters the porous alumina ceramic plate, where the distillation The temperature of the water is 36°C, and the temperature-sensitive hydrogel is in a de-swollen state;
The temperature of the distilled water is lowered to 25° C., and the distilled water is adsorbed into the temperature-sensitive hydrogel in the presence of a solid phase to obtain a heat-insulating layer, where the temperature-sensitive hydrogel is in a swollen state;
The heat insulating layer, the skin and the underplate are fixed by screws and nuts to obtain an underplate having a heat shield structure. Here, a high temperature alloy plate of 100 mm x 100 mm x 5 mm is used as the skin, an aluminum alloy plate of 100 mm x 100 mm x 5 mm is used as the underplate material, and M4 alumina ceramic screws and nuts are used as the screws and nuts. is used. Here, nuts are fixed on both sides of the skin, retaining an 8 mm cavity layer between the insulation layer and the skin.
The manufactured underplate with heat shield structure was placed on a heat insulating blanket, thermocouples were glued to the outer surface of the skin and the outer surface of the heat insulating layer, respectively, and it was placed under a high-power quartz lamp, and the heat flux was controlled by the high-power quartz lamp. was adjusted to 0.9 MW/ ^m2 , a thermal check test was performed, and the measured external surface temperature of the skin was 865°C, the external surface temperature of the insulation layer was 100°C or less, and 3 min (the effectiveness of the active heat shield mechanism) was determined. time) was maintained.

Example 2
Example 2 is almost the same as the manufacturing method of Example 1, but differs in the following points.
The heat flux was 0.1 MW/m ² and the thickness of the porous alumina ceramic plate was 5 mm.
The measured outer surface temperature of the skin was 420° C., and the effective time of the active heat shield mechanism was 30 min.

Example 3
Example 3 is almost the same as the manufacturing method of Example 1, but differs in the following points.
The heat shield structure is placed in a high frequency plasma wind tunnel, the heat flux is adjusted to 5 MW/ ^m2 , and the thickness of the porous alumina ceramic plate is 15 mm.
The measured outer surface temperature of the skin was 870° C., and the effective time of the active heat shield mechanism was 15 min.

Example 4
Example 4 is almost the same as the manufacturing method of Example 1, but differs in the following points.
The heat shield structure is placed in a high frequency plasma wind tunnel, the heat flux is adjusted to 10 MW/ ^m2 , and the thickness of the porous alumina ceramic plate is 30 mm.
The measured outer surface temperature of the skin was 910° C., and the effective time of the active heat shield mechanism was 20 min.

Comparative example 1
A high temperature alloy plate of 100 mm x 100 mm x 5 mm is selected as the skin, a thermocouple is glued on the outer surface of the skin, and it is left under a high power quartz lamp, and the heat flux is set to 0.9 MW/ ^m2 by the high power quartz lamp. A thermal check test was conducted, and the measured external temperature of the skin was 1170°C.

The thermal check test data of Examples 1 to 4 and Comparative Example 1 are summarized as shown in Table 1.

As can be seen from Examples 1 to 4, the heat shield structure provided by the present invention can withstand a heat load of up to 10 W/ ^m2 , and the effective time of the active heat shield mechanism can reach 30 min. .

From Examples 1 to 4, the active heat shield mechanism in the heat shield structure of the present invention has an excellent heat shield effect, and can control the outer surface temperature of the internal cabin of the flying object to 100°C or less, Moreover, it was further clarified that the time of the active heat shield mechanism can be adjusted by changing the thickness and heat flux of the porous insulation structure.

From Example 1 and Comparative Example 1 (for example, FIG. 4), it is found that the outer surface temperature of the skin of Example 1 is 865° C., and the outer surface temperature of the skin of Comparative Example 1 is 1170° C., and the present invention provides It has been proven that the heat shielding structure can improve the heat shielding effect of the material by internal radiation in passive heat shielding mechanism.

As mentioned above, the above embodiments do not limit the technical solutions of the present invention, but are intended to explain them, and the present invention has been explained in detail with reference to the above embodiments, but those skilled in the art will understand. As such, it can still modify the technical solutions described in each of the above embodiments, or equivalently replace some constituent elements thereof, and these modifications or replacements may The essence of the technical solution does not depart from the spirit and scope of the technical solution of each embodiment of the present invention.

Claims (10)

an insulating layer, a cavity layer, and a skin disposed in sequence, the insulating layer being disposed on an exterior surface of an interior cabin of the vehicle;
The heat insulating layer includes a porous heat insulating structure, a temperature sensitive hydrogel provided in the porous heat insulating structure, and a cooling substance adsorbed in the temperature sensitive hydrogel,
When the heat shielding structure does not provide heat shielding, the temperature sensitive hydrogel is in a swollen state and the cooling agent is adsorbed into the temperature sensitive hydrogel in the form of a solid phase;
When the heat shielding structure performs heat shielding, the temperature-sensitive hydrogel absorbs the heat radiated inward from the skin and the hollow layer, becomes a de-swelled state, and converts the cooling working material into a solid phase. A heat shield structure characterized in that the cooling substance in the vapor phase is sequentially transformed into a liquid phase and a gas phase, and is discharged after being released into the cavity layer. The heat shield structure further includes a screw and a nut, and the heat insulating layer and the skin are fixed on an outer surface of the internal cabin of the aircraft by engagement of the screw and the nut. The heat shield structure according to item 1. 3. The heat shield structure of claim 2, wherein the screw and the nut are both made of alumina ceramic. Heat shield structure according to any one of claims 1 to 3, characterized in that the porous insulation structure is made of alumina ceramic. The heat shield structure according to any one of claims 1 to 4, wherein the cooling substance contains water. disposing a temperature-sensitive hydrogel and a porous insulation structure in a container containing a cooling working substance, and allowing the temperature-sensitive hydrogel to enter the porous insulation structure, the temperature of the cooling working substance increasing the temperature of the cooling working substance; is a first predetermined temperature, and the temperature-sensitive hydrogel is in a de-swelled state under the first predetermined temperature;
lowering the temperature of the cooling substance to a second predetermined temperature and adsorbing the cooling substance in the form of a solid phase into the temperature-sensitive hydrogel to obtain a heat insulating layer, the temperature-sensitive hydrogel is in a swollen state at a predetermined temperature;
fixing the heat insulating layer and the skin, and installing a hollow layer between the heat insulating layer and the skin to form a heat shield structure, the heat insulating layer being provided on an outer surface of the interior cabin of the aircraft; and the steps
A method of manufacturing a heat shield structure, comprising: The step of fixing the heat insulating layer and the skin includes:
7. The method of manufacturing a heat shield structure according to claim 6, further comprising fixing the heat insulating layer and the skin using engagement between screws and nuts. 8. The method of manufacturing a heat shield structure according to claim 7, wherein the screw and the nut are both made of alumina ceramic. A method for manufacturing a heat shield structure according to any one of claims 6 to 8, characterized in that the porous heat insulation structure is made of alumina ceramic. The method for manufacturing a heat shield structure according to any one of claims 6 to 9, wherein the cooling substance contains water.

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