JP5225806B2 - Insulation material and fairing, recovery capsule, and spacecraft including the same - Google Patents

Description

  The present invention is suitably applied to the outer walls of aircraft such as fairings such as rockets that fly while being exposed to aerodynamic heating in the atmosphere, and recovery capsules and space shuttles that are recovered by re-entering the atmosphere in the spacecraft system. Related to insulation that can be.

  The fairing outer surface at the tip of the rocket flying at high speed in the atmosphere is exposed to a severe aerodynamic heating environment due to collision with air molecules and adiabatic compression of air. In order to prevent heat from entering into the airframe due to such aerodynamic heating, the outer wall of the fairing is covered with a heat insulating material as a heat protection material.

As a typical heat insulating material, there is a silicone heat insulating material or a cork heat insulating material.
The thermal decomposition layer made of such a silicone-based heat insulating material or cork-based heat insulating material is subjected to aerodynamic heating, and the surface portion that is heated to cause thermal decomposition to generate pyrolysis gas, and the surface of the thermal decomposition layer The part itself carbonizes. Since this reaction is mainly an endothermic process, it is possible to prevent the temperature of the pyrolysis layer from rising.

  In addition, the pyrolysis gas generated in this process is ejected to the outside and flows away along with the external air flow along the surface of the pyrolysis layer. For this reason, it is prevented that the external high-temperature air current directly contacts the pyrolysis layer, and the amount of heat input can be reduced.

  Further, the surface portion of the pyrolysis layer that has undergone pyrolysis becomes a breathable carbide and becomes a passage for pyrolysis gas generated from the inside. This carbide is oxidized and burned by further aerodynamic heating to generate combustion gas and wear. The combustion gas generated at this time also has a function of shielding the high-temperature air stream together with the pyrolysis gas. By sequentially proceeding with such a process, the pyrolysis layer gradually wears away from the surface and functions to shield the high temperature air flow.

  At this time, some carbides may drift around the fairing due to the impact caused by the opening of the fairing, and may adhere to the mounted equipment after the opening of the fairing and cause contamination. It can be a factor that causes inconveniences.

  In addition, since the heat insulating material is exposed to the outside and provided on the fairing, there is a possibility of repeated collisions due to raindrops during stormy weather. Since repeated impact of raindrops causes erosion (rain erosion) on the surface of the heat insulating material, at least the outermost layer of the heat insulating material must be resistant to such erosion. Conventional silicone-based heat insulating materials and cork-based heat insulating materials require measures against this rain erosion, and a top coat having rain erosion resistance is applied to the outer surface of the heat insulating material.

  However, the top coat itself may deteriorate and become contaminated under the severe aerodynamic heating environment as described above. Furthermore, this conventional top coat has low air permeability, and the conventional heat insulating material on which the top coat is applied is a pyrolytic gas generated from the heat insulating material when heated when exposed to a severe aerodynamic heating environment. Could not be released to the outside. Therefore, there is a possibility that the pressure of the pyrolysis gas increases between the top coat layer and the airframe, and the heat insulating material itself delaminates from the airframe.

  Furthermore, when launching a rocket or the like, the heat insulating material exposed to the outside is exposed to an environment irradiated with sunlight. When a cork-based heat insulating material is used as the heat insulating material, the absorption of sunlight increases, and therefore the temperature of the outer surface of the heat insulating material and the inside of the fairing increases. When launching a rocket or the like, it is necessary to prevent the temperature rise inside the fairing as much as possible, and therefore it is necessary to reduce the absorption rate of sunlight. Therefore, when using a cork-based heat insulating material, it is necessary to make the outer surface of the heat insulating material white, and from this point of view, a top coat is indispensable for conventional heat insulating materials.

  In addition to the above-mentioned silicone-based heat insulating material or cork-based heat insulating material, it comprises a lightweight heat-insulating rubber composition having excellent adhesiveness and workability that can be applied without using an adhesive as other conventional heat insulating material. A heat insulating material is proposed in Patent Document 1, for example. However, when such a heat insulating material is used for, for example, the above-described fairing and the surface portion of the heat insulating material is carbonized by aerodynamic heating, a part of the carbide generated in the surface portion is opened to the fairing cranio Due to the accompanying impact, there is a possibility of drifting around the fairing. That is, even in such a heat insulating material, some carbides may adhere to the mounted equipment after the opening of the fairing, resulting in contamination.

  Further, as a heat insulating material of another prior art, a slurry containing SiC powder and / or SiC whisker in addition to the heat resistant inorganic fiber is dehydrated between the high temperature side skin material and the low temperature side skin material made of the heat resistant inorganic fiber fabric. For example, Patent Document 2 discloses a heat insulating material in which a molded core material is interposed and integrated. However, such a heat insulating material has high water absorption, and raindrops that collided permeate into the heat insulating material during stormy weather, resulting in a decrease in heat insulating performance. In order to prevent this, it is necessary to apply a top coat to the outermost layer. In this case, the top coat is made of glass that has the same heat resistance as that of the inorganic insulation. However, this top coat has high rigidity, low acoustic vibration resistance, and impact during fairing separation. May cause crushing and contamination.

Japanese Patent No. 2990534 Japanese Patent No. 3490628

  The present invention has been made in view of the above-described problems, and has heat resistance that is resistant to rain erosion and aerodynamic heating, and that can suppress the occurrence of contamination, and a fairing and recovery that includes the heat insulating material. The purpose is to provide a capsule and a space shuttle.

The present invention has heat resistance against aerodynamic heating and has a breathable surface layer;
The surface layer is laminated on one surface, the other surface is joined to the substrate, and saw including a thermally decomposing thermally decomposable layer by aerodynamic heating of the surface layer,
The surface layer and the pyrolysis layer are sewn by fibers having heat resistance equivalent to or higher than that of the surface layer,
The surface layer is made of glass cloth,
The thermal decomposition layer is a heat insulating material made of silicone foam or carbon foam .

  According to the present invention, the surface layer is provided on the surface of the pyrolysis layer on the side subjected to aerodynamic heating. This surface layer is formed so as to have heat resistance and breathability against assumed aerodynamic heating. The heat insulating material formed including the surface layer and the pyrolysis layer is bonded to the base on the pyrolysis layer side. As the base body to which the heat insulating material is bonded flies in the air at high speed, the heat insulating material is subjected to severe aerodynamic heating.

  The aerodynamic heating environment received by the heat insulating material is simulated in advance on the basis of flight conditions such as a mounted fairing, and the surface layer has heat resistance to at least the most severe aerodynamic heating environment. Therefore, it can be avoided that the surface layer itself deteriorates and becomes a contamination.

  In addition, the pyrolysis layer is pyrolyzed by heating accompanying aerodynamic heating to generate pyrolysis gas, and the surface portion of the pyrolysis layer itself is carbonized. Since the surface layer has air permeability as described above, the pyrolysis gas generated in the pyrolysis layer can be ejected to the outside through the surface layer. As described above, the heat absorption effect by the pyrolysis of the pyrolysis layer and the heat shielding effect by the ejection of the pyrolysis gas can improve the resistance to aerodynamic heating.

  Further, the surface layer prevents scattering of carbides generated with the pyrolysis of the pyrolysis layer to the outside. Accordingly, the carbide generated in the pyrolysis layer is prevented from scattering to the outside due to an impact applied to the substrate, and thus the carbide can be prevented from scattering to the outside and causing contamination. .

  Furthermore, since the surface layer is laminated on the pyrolysis layer, it is possible to prevent raindrops from directly colliding with the pyrolysis layer. Therefore, it is possible to suppress the thermal decomposition layer from being worn, and to prevent the thermal protection performance from being lowered due to the wear of the thermal decomposition layer.

In addition , since the surface layer and the pyrolysis layer are sewn, it is possible to reliably prevent the surface layer from peeling off from the pyrolysis layer due to generation of pyrolysis gas in the pyrolysis layer accompanying aerodynamic heating. Can do.

  In addition, the fibers used for sewing have the same heat resistance as the surface layer or higher heat resistance than the surface layer. Have heat resistance. Here, having heat resistance higher than the heat resistance of the surface layer means having a heat resistance temperature higher than the heat resistance temperature of the surface layer. Therefore, it can be avoided that the fiber itself used for sewing deteriorates and causes contamination.

Also, a silicone foam or carbon foam pyrolysis layer, by using glass cloth scan the surface layer, and having a resistance to rain erosion and aerodynamic heating, it is possible to suppress the occurrence of contamination, lightweight thermal insulation Can be realized.

Moreover, this invention is a fairing characterized by the said heat insulating material being joined.
According to the present invention, it is possible to realize a fairing that has resistance to rain erosion and aerodynamic heating and can suppress the occurrence of contamination.

Moreover, this invention is a collection | recovery capsule characterized by the said heat insulating material being joined to an outer wall.
According to the present invention, it is possible to realize a recovery capsule that has resistance to rain erosion and aerodynamic heating and can suppress the occurrence of contamination in outer space.

The present invention is also a spacecraft, wherein the heat insulating material is joined to an outer wall.
According to the present invention, it is possible to realize a spacecraft that has resistance to rain erosion and aerodynamic heating and can suppress the occurrence of contamination in outer space.

  According to the present invention, the pyrolysis gas generated in the pyrolysis layer can be released to the outside through the air permeable surface layer, so that the resistance to aerodynamic heating can be improved. Moreover, since the carbide | carbonized_material generated at the time of thermal decomposition can be capture | acquired by the surface layer, generation | occurrence | production of contamination can be suppressed. Therefore, it is possible to prevent the malfunction of the on-board equipment and the like due to the occurrence of contamination and to suppress the occurrence of contamination with respect to outer space. Moreover, since rain erosion due to raindrops and icedrops can be prevented, wear of the heat insulating material can be prevented, and high reliability with respect to an environment such as a fairing equipped with the heat insulating material can be achieved.

Also, even in severe aerodynamic heating environment, it is possible to reliably prevent the surface layer peeled off from the pyrolysis layer. Therefore, a highly reliable heat insulating material can be realized.

Also, because of the use of silicone foams or carbon foam thermal decomposition layer, it is possible to realize a lightweight thermal insulation material as much as possible.

  Moreover, according to this invention, the fairing which can be implemented suitably can be implement | achieved.

  Moreover, according to this invention, the collection | recovery capsule which can be implemented suitably can be implement | achieved.

  Further, according to the present invention, it is possible to realize a spacecraft that can be suitably implemented.

  FIG. 1 is a partial cross-sectional view showing a configuration of a heat insulating material 1 according to an embodiment of the present invention, and is an enlarged cross-sectional view of a section A in FIG. FIG. 2 is a side view of the rocket fairing according to the embodiment of the present invention, and a cross-sectional view is shown at the notched portion.

  A fairing 10 provided at the leading portion of the rocket, which is a high-speed flying object, is disposed upstream of the traveling direction, exposed to a high aerodynamic heating rate, and formed into a substantially hemispherical shape, and a nose cap portion 11. The cone portion 12 is formed in a substantially truncated cone shape, and the cylinder portion 13 is formed in a substantially cylindrical shape. In order to open the fairing 10 at the end of the cone part 12, the cylinder part 13 and the fairing 10 on the most downstream side in the traveling direction in order to release the device mounted in the fairing 10 into outer space. The separation mechanisms 14, 15, and 16 are provided.

  The cone portion 12 includes, for example, a honeycomb panel 4 that is a base and a metal coat layer 6 that covers the inner surface 4b of the honeycomb panel 4, and the outer surface 4a of the honeycomb panel 4 is accompanied by high-speed flight of a rocket. In order to prevent heat from entering the inside of the fairing 10 by aerodynamic heating, the heat insulating material 1 is bonded via the adhesive layer 5.

  The heat insulating material 1 of the present embodiment includes a glass cloth 3 and a silicone foam 2. The glass cloth 3 is a surface layer having heat resistance and air permeability with respect to assumed aerodynamic heating. The silicone foam 2 is a pyrolysis layer that is thermally decomposed by aerodynamic heating to the glass cloth 3, and the thickness is set so that the temperature of the honeycomb panel 4 is equal to or lower than the heat resistant temperature for the assumed aerodynamic heating. Yes. The silicone foam 2 has a glass cloth 3 laminated on the surface 2a on the side subjected to aerodynamic heating, and the surface 2b opposite to the surface 2a is bonded to the honeycomb panel 4 of the fairing 10, for example, with silicone. It joins via the adhesive material layer 5 which consists of an agent. Such a heat insulating material 1 may be formed by foaming silicone on a glass cloth. By using the silicone foam 2 in which silicone is foamed as the thermal decomposition layer, the heat insulating material 1 itself can be reduced in weight.

  Moreover, in the heat insulating material 1, although not shown in figure, the glass cloth 3 and silicone foam 2 are used using the fiber which has heat resistance equivalent to the glass cloth 3, or higher heat resistance than the glass cloth 3 has. And are joined by sewing. As such fibers, glass fiber yarns may be used. As an example of sewing, it can be realized by sewing the above-described fibers in a lattice shape at a pitch of 20 mm.

  The fairing 10 to which such a heat insulating material 1 is joined rises to the outer surface of the cone portion 12, for example, at about 600 ° C. by aerodynamic heating accompanying high-speed flight of the rocket. FIG. 3 is a cross-sectional view showing the heat insulating material 1 in a state of receiving aerodynamic heating accompanying high-speed flight of the rocket. Since the glass cloth 3 used in the present embodiment has heat resistance even at 800 to 900 ° C., it is stably present in an aerodynamic heating environment that rises to about 600 ° C. Therefore, the glass cloth 3 can be used as a surface layer for the cone portion 12 of the fairing 10 that receives aerodynamic heating so that the outer surface rises to about 600 ° C.

  Moreover, the allowable temperature of the silicone foam 2 used suitably for weight reduction is 300-400 degreeC. That is, in an aerodynamic heating environment where the outer surface rises to about 600 ° C., the temperature of the outer surface exceeds the allowable temperature. Here, the allowable temperature in the silicone foam 2 is a temperature at which the silicone foam 2 is not thermally decomposed, that is, a temperature at which the silicone foam 2 does not deteriorate. Therefore, when the silicone foam 2 is used as the heat insulating material for the cone portion 12 as it is, the silicone foam 2 is heated to a temperature exceeding the allowable temperature by the aerodynamic heating, and thus pyrolyzes to generate pyrolysis gas. At the same time, the thermally decomposed silicone foam 2 is deteriorated by carbonization, which causes contamination.

  Since the heat insulating material 1 of the present embodiment is formed by laminating the glass cloth 3 on the silicone foam 2 as described above, the outer surface of the heat insulating material 1 is heated to around 600 ° C. by the assumed aerodynamic heating. Even so, the thickness of the silicone foam 2 is set so that the temperature on the honeycomb panel 4 side of the silicone foam 2 is equal to or lower than the heat-resistant temperature of the honeycomb panel 4. Therefore, the honeycomb panel 4 can be reliably thermally protected from the assumed aerodynamic heating. Moreover, since the glass cloth 3 has heat resistance against the surface temperature raised by the assumed aerodynamic heating, the form can be maintained even if the glass cloth 3 itself is carbonized or incinerated. There is no contamination.

  In addition, when the heat insulating material 1 is subjected to the assumed aerodynamic heating, the silicone foam 2 heated to exceed the allowable temperature causes thermal decomposition on the surface portion on the side subjected to the aerodynamic heating, and generates pyrolysis gas. Occur. At this time, since the glass cloth 3 is formed to have air permeability, the pyrolysis gas generated from the silicone foam 2 can pass through the glass cloth 3. Therefore, it is possible to reliably realize the heat shielding effect by the ejection of the pyrolysis gas. At the same time, it is possible to prevent the pressure between the glass cloth 3 and the honeycomb panel 4 from increasing, and to prevent the heat insulating material 1 from peeling from the honeycomb panel 4.

  Further, the surface portion of the pyrolysis layer is carbonized as the pyrolysis gas is generated to become the carbonized layer 7, and some carbides are separated from the carbonized layer 7 and exist as fine particles 8. However, since the glass cloth 3 is laminated on the silicone foam 2, it is possible to prevent the carbide particles 8 from scattering to the outside as much as possible. Here, the glass cloth 3 itself may be formed so as to have a finer mesh than the particle diameter of the carbide particles 8. By providing such a glass cloth 3, even when the silicone foam 2 is deteriorated, the generated carbide particles 8 can be attached to and captured by the glass cloth 3, so that the occurrence of contamination is suppressed as much as possible. can do. The trapping of the carbide particles 8 is performed by physical adsorption, and the trapped carbide particles 8 are entangled with the fibers on the surface of the glass cloth 3.

  In addition, the fairing 10 according to the present embodiment has a device mounted therein, and the fairing 10 is opened in order to release the mounted device to outer space. The opening of the fairing 10 is performed by operating the separation mechanisms 14 to 16, and the operation of the separation mechanisms 14 to 16 is accompanied by an impact. When the fairing 10 is opened after the carbonized layer 7 is formed on the silicone foam 2, a large amount of the carbide particles 8 are peeled off from the carbonized layer 7 with the separation impact. However, since the glass cloth 3 is provided as described above, the carbide particles 8 are captured by adhering to the glass cloth 3. For this reason, it is possible to prevent the occurrence of contamination that may cause a malfunction of the mounted device or the like.

  Moreover, since the heat insulating material 1 of the present embodiment is formed by foaming silicone on the glass cloth 3, the glass cloth 3 and the silicone foam 2 are bonded in advance, but with aerodynamic heating. By forming the carbonized layer 7 on the surface portion of the silicone foam 2, the interfacial adhesive force between the glass cloth 3 and the silicone foam 2 is reduced, and the glass cloth 3 may be peeled from the silicone foam 2. There is. However, since it is reinforced by the glass fiber yarn as described above, it is possible to reliably prevent the glass cloth 3 from peeling off.

  Moreover, since the glass cloth 3 is laminated on the silicone foam 2, it is possible to prevent raindrops from directly colliding with the silicone foam 2. Further, since the glass cloth 3 is made of a material harder than the silicone foam 2, it is possible to prevent the silicone foam 2 from being worn out by rain erosion. Therefore, high reliability with respect to the environment of the fairing 10 on which the heat insulating material 1 is mounted can be achieved.

  The glass cloth 3 has an emissivity ε of 0.8 to 0.9 and a sunlight absorption rate αs of 0.2 to 0.3. Since the solar absorptance αs is formed in this way, even when the heat insulating material 1 exposed to the outside is exposed to the environment irradiated with sunlight when the rocket is launched, the heat insulating material 1 temperature rise can be prevented. Therefore, a top coat for making the outer surface of the heat insulating material 1 white is unnecessary.

  Moreover, the silicone foam 2 with the glass cloth 3 has good moldability and excellent flexibility. Furthermore, it is possible to easily adhere to the substrate 4 using a silicone adhesive.

  Further, the environmental resistance of the silicone foam 2 with the glass cloth 3 will be described. Since only the glass cloth 3 absorbs water or absorbs moisture, the heat insulating material 1 has extremely low water absorption and hygroscopicity. With respect to the rain erosion resistance and weather resistance (tested by salt spray), the glass cloth 3 is provided, so that it has good properties. Moreover, since the rigidity of the heat insulating material 1 is low and flexible with respect to acoustic vibration resistance, it has favorable properties.

  The applicant is testing the silicone foam 2 with the glass cloth 3 which is the heat insulating material 1 of the present embodiment by an arc heating test. In this test, the surface of the heat insulating material 1 on the glass cloth 3 side is heated, and the temperature of the surface is heated to about 540 ° C. The back surface temperature of the heat insulating material 1 at this time was 107 ° C. In response to such heating, although the glass cloth 3 had a slightly discolored surface, deterioration due to heat was not a problem.

  A test for separation impact resistance is performed on the heat insulating material 1 to which a heating load is applied by an arc heating test. That is, a test for examining the amount of contamination with respect to the separation impact associated with the opening of the fairing as described above has been conducted. Specifically, it is performed by dropping the heat insulating material 1 after the heating load from a height of 60 cm. For this test, almost no generation of contamination was confirmed from the heat insulating material 1 after the heating load.

  As described above, the silicone foam 2 with the glass cloth 3, which is the heat insulating material 1 of the present embodiment, has resistance to rain erosion and aerodynamic heating, and is suitable as a heat insulating material that can suppress the occurrence of contamination. Can be implemented.

  In another embodiment of the present invention, the above-described heat insulating material 1 may be bonded to the recovery capsule and the outer wall of the spacecraft. Recovery capsules and spacecraft are subject to severe aerodynamic heating during navigation in the atmosphere. Therefore, by providing the heat insulating material 1, it has resistance to aerodynamic heating and can suppress the occurrence of contamination in outer space and the like. It can also be provided with resistance to rain erosion.

  In another embodiment of the present invention, carbon cloth may be used instead of glass cloth, and carbon foam may be used instead of silicone foam. Moreover, you may use combining these freely. Even when the combination is changed, it can be suitably implemented as a heat insulating material having resistance to rain erosion and aerodynamic heating and capable of suppressing the occurrence of contamination. Moreover, since it can combine freely, material can be suitably selected according to various design conditions.

  In another embodiment of the present invention, the heat insulating material 1 and the base 4 may be joined with a bolt or a stapler instead of the adhesive. By doing in this way, peeling with the heat insulating material 1 and the base | substrate 4 can be prevented reliably. At the same time, peeling between the glass cloth 3 and the silicone foam 2 can be reliably prevented without sewing with the glass fiber thread.

FIG. 3 is a partial cross-sectional view illustrating a configuration of a heat insulating material 1 according to an embodiment of the present invention, and is an enlarged cross-sectional view of a section A in FIG. 2. It is a side view of the rocket fairing of one Embodiment of this invention, and has shown sectional drawing in the notch location. It is sectional drawing which shows the heat insulating material 1 of the state which has received the aerodynamic heating accompanying the high-speed flight of a rocket.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat insulating material 2 Silicone foam 3 Glass cloth 4 Honeycomb panel 5 Adhesive layer 10 Fairing

Claims (4)

A heat-resistant surface layer for aerodynamic heating, and a breathable surface layer;
The surface layer is laminated on one surface, the other surface is joined to the substrate, and saw including a thermally decomposing thermally decomposable layer by aerodynamic heating of the surface layer,
The surface layer and the pyrolysis layer are sewn by fibers having heat resistance equivalent to or higher than that of the surface layer,
The surface layer is made of glass cloth,
The thermal decomposition layer is made of silicone foam or carbon foam . A fairing, wherein the heat insulating material according to claim 1 is joined. 2. A recovery capsule, wherein the heat insulating material according to claim 1 is bonded to an outer wall. A spacecraft, wherein the heat insulating material according to claim 1 is joined to an outer wall.

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