JP2017081285A - Missile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a missile with an ablator which is secured in heat protection characteristics while maintaining the strength.SOLUTION: A missile comprises a high fiber density ablator part 5 which is provided on an external surface S side of a body and is mainly composed of resin and a fiber matrix, and low fiber density ablator parts 7 which have a lower fiber density than that of the high fiber density ablator part 5 and are mainly composed of resin and a fiber matrix. The high fiber density ablator part 5 is formed with grooves 9, and the low fiber density ablator parts 7 are formed in the grooves 9. The grooves 9 are in communication with an external surface S.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a flying body having a heat insulating structure by an ablator material.

As for the flying body which performs high-speed flight, it is assumed that a front-end | tip part becomes high temperature by aerodynamic heating. Therefore, in order to protect the internal structure of the flying body from heat, it is necessary to take measures against heat.
Ablation is one of the heat protection measures. This is because the ablation material mainly composed of resin and fiber is placed on the outer surface of the flying body, and the ablation gas generated by sublimation, melting or carbonization of the heated ablator material covers the outer surface. This is a method of performing protection (see Patent Document 1).

Japanese Patent No. 5638271

  The tip of the flying body must have a high-strength structure due to the dynamic pressure during navigation, but the low fiber density ablator material, which has a high vaporization rate to vaporize the ablator material, has a relatively low strength, so it is necessarily It is necessary to employ an ablator material having high fiber density strength. However, since the ablator material having a high fiber density has a low vaporization rate, there is a problem that the heat insulation effect by ablation is low.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the flying body provided with the ablator material with which heat protection property was ensured, maintaining intensity | strength.

In order to solve the above problems, the flying body of the present invention employs the following means.
That is, the flying body according to the present invention is provided on the outer surface side of the main body, and includes a high fiber density ablator part having an ablator material mainly composed of a resin and a fiber matrix, and the ablator material of the high fiber density ablator part. A low fiber density ablator part having an ablator material mainly composed of a resin and a fiber matrix, and a groove is formed in the high fiber density ablator part. The groove is provided in the groove, and the groove communicates with the outer surface.

  The high fiber density ablator has a lower strength than the low fiber density ablator but has a lower vaporization rate of the ablator material. Therefore, a high fiber density ablator is disposed on the outer surface of the flying body. On the other hand, the low fiber density ablator part is provided in a groove formed in the high fiber density ablator part. Since the low fiber density ablator part has a higher vaporization rate of the ablator material than the high fiber density ablator part, it can be vaporized even if it is provided in the groove of the high fiber density ablator part. The ablation gas vaporized by the ablator material of the low fiber density ablator part can reach the outer surface and cover the outer surface by the groove communicating with the outer surface, thereby preventing heat.

  Furthermore, according to the flying body of the present invention, the entire surface of the groove on the outer surface side is open to the outer surface.

Since the entire surface on the outer surface side of the groove is open to the outer surface, the low fiber density ablator portion provided in the groove faces the main stream flowing along the outer surface. Thereby, it becomes easy to vaporize an ablator material, generation | occurrence | production of ablation gas can be accelerated | stimulated, and a heat-insulating effect can be improved.
Further, the groove serves as a cavity, and vaporized ablation gas can stay in the groove to improve heat insulation.

  Furthermore, according to the flying body of the present invention, the longitudinal cross-sectional shape of the groove viewed from a cut surface including the longitudinal axis of the main body is a quadrangle.

Many low fiber density ablator parts can be accommodated by making the longitudinal cross-sectional shape of a groove | channel into a square.
The ratio of the mainstream boundary layer thickness to the groove width at the upstream end of the groove is preferably 0.28 or more, and more preferably 0.28. Thereby, since the heat transfer coefficient at the bottom surface of the groove is suppressed to be relatively low, vaporization of the low fiber density ablator portion located at the groove bottom surface portion can be suppressed, and the strength can be maintained for a relatively long period.

  Furthermore, according to the flying body of the present invention, the longitudinal cross-sectional shape of the groove viewed from a cut surface including the longitudinal axis of the main body is a triangle.

By making the longitudinal cross-sectional shape of the groove triangular, an inclined surface can be formed at the edge on the outer surface of the groove, so that separation of the mainstream flow can be suppressed as much as possible.
Since there are few corners compared to a square groove, the number of stress concentration points is reduced, and the strength can be relatively increased.
The low fiber density ablator part gradually disappears from the outer surface side due to heat from the mainstream, but since the groove is triangular, the surface area where the low fiber density ablator part is exposed to the mainstream side is the ablator material. It becomes smaller with vaporization. Therefore, a large amount of ablation gas is generated at the beginning of flight to demonstrate high heat insulation performance, and at the end of flight, the surface area of the low fiber density ablator is reduced, and the surface area of the high fiber density ablator is relatively increased. Can be kept high. Thus, it is effective for flying objects that require thermal protection in the early stage of flight.
In addition, the angle of each vertex of a triangle can be variously changed and is adjusted according to the flight plan of a flying body.

  Furthermore, according to the flying body of the present invention, the groove is formed inside the high fiber density ablator part separated from the outer surface and communicated by a hole part connecting the outer surface. It is characterized by being.

Since the groove is formed inside the high fiber density ablator part separated from the outer surface, and the low fiber density ablator part is arranged in this groove, the mainstream is mainly vaporized more than the low fiber density ablator part. It can be set as a difficult high fiber density ablator part, and the shape change of an outer surface can be suppressed as much as possible.
The low fiber density ablator part provided in the groove is heated and vaporized by heat input from the outer surface. The vaporized ablation gas is guided to the outer surface through a hole connecting the groove and the outer surface, and then covers the outer surface to prevent heat.
Since the ablation gas stays inside the groove after the low fiber density ablator is vaporized, the heat insulation effect can be improved.

  Furthermore, according to the flying body of the present invention, the hole portion is inclined toward the downstream side in the mainstream flow direction.

Since the hole portion is inclined downstream in the mainstream flow direction, the ablation gas can flow smoothly.
Furthermore, it is preferable that the flow path cross-sectional area of the hole gradually increases toward the downstream side in the mainstream flow direction on the downstream side of the outer surface of the hole. This can guide the ablation gas over a wide area of the outer surface.

  Furthermore, according to the flying body of the present invention, a plurality of the grooves are provided in the flow direction of the main flow flowing along the outer surface, and the groove width of the grooves in the flow direction of the main flow is closer to the upstream side of the main flow. It is characterized by being enlarged.

  Among the plurality of grooves, since the groove width is larger toward the upstream side of the main stream, a large amount of ablation gas can be generated from the upstream side grooves, and the heat insulation effect can be enhanced.

  Furthermore, according to the flying body of the present invention, only one groove is provided in the flow direction of the main flow that flows along the outer surface.

  Since the temperature rises due to heat input from the main stream on the tip side of the flying body, only one groove may be formed to guide the ablation gas from the low fiber density ablator part to the outer surface on the downstream side. As a result, less groove processing is required, and the material cost of the low fiber density ablator portion can be saved.

  Furthermore, according to the flying body of the present invention, the groove is provided so as to communicate with the joint portion where the high fiber density ablator portions are connected to each other.

  A groove was provided so as to communicate with a joint portion where the high fiber density ablator parts were attached to each other and connected, and the low fiber density ablator part was arranged. As a result, the ablation gas vaporized in the groove stays in the gap between the groove and the joint, and a thermal insulation effect is obtained, and the external high-temperature gas passes through the gap in the joint and enters the flying object. Can be prevented.

  The strength can be maintained by arranging the high fiber density ablator on the outer surface of the flying body. And by providing the low fiber density ablator part in the groove formed in the high fiber density ablator part, the ablation gas vaporized by the ablator material of the low fiber density ablator part is guided to the outer surface communicating with the groove, ensuring thermal protection can do.

It is the side view which showed the front-end | tip part of the flying body of this invention. FIG. 2 is a partially enlarged longitudinal sectional view showing the vicinity of the outer surface of FIG. 1 according to the first embodiment of the present invention. It is a longitudinal cross-sectional view which shows a cavity flow. It is the graph which showed the relationship between the cavity shape shown in FIG. 3, and the Nusselt number. It is the partial expanded longitudinal cross-sectional view which showed 2nd Embodiment of this invention. It is the partial expanded longitudinal cross-sectional view which showed 3rd Embodiment of this invention. It is the perspective view which showed the downstream part of the hole of FIG. It is the partial expansion longitudinal cross-sectional view which showed the modification of 3rd Embodiment. FIG. 4A is a partial longitudinal sectional view showing a tip of a flying object, and FIG. 5B is a transverse sectional view of the flying object according to a fourth embodiment of the present invention. It is sectional drawing which showed the A section detail of FIG.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, the tip 1 a of the flying body 1 is shown. The tip portion 1a has a tapered shape in which a cross section perpendicular to the longitudinal axis L is circular. The tip portion 1a is a portion that becomes high temperature by aerodynamic heating when the flying body 1 performs high-speed flight, and is a portion to which a load due to dynamic pressure during navigation is applied.

As shown in FIG. 2, the flying body 1 includes a structural material 3 for housing and protecting internal equipment, and a high fiber density ablator 5 provided so as to surround the outer periphery of the structural material 3. ing.
A plurality of grooves 9 are formed on the outer surface of the high fiber density ablator portion 5 at predetermined intervals in the mainstream flow direction. Each groove 9 is an endless recess formed around the longitudinal axis L (see FIG. 1) of the tip 1 a of the flying body 1. As shown in FIG. 2, each groove 9 has a rectangular cross-sectional shape, and the entire surface on the outer surface S side is open. In addition, each groove 9 has a larger groove width in the flow direction of the main flow MF as the groove 9 on the upstream side.

  Each groove 9 is filled with a low fiber density ablator 7. In FIG. 2, the outer surface S side of the low fiber density ablator part 7 is partially vaporized and disappeared, but before the vaporization, the outer surface S of the flying object 1 is covered with the high fiber density ablator part 5. It is designed to form on a continuous surface.

  The high fiber density ablator part 5 and the low fiber density ablator part 7 are made of an ablator material mainly composed of a resin and a fiber matrix, and are formed by impregnating the fiber matrix with a resin. Examples of the resin include silicon resin, epoxy resin, and phenol resin. Examples of the fiber matrix include carbon fiber, glass fiber, and silica fiber. The ablator material used as the high fiber density ablator part 5 has a density about three times that of the ablator material used for the low fiber density ablator part 7 (for example, 0.6 g / cm 3).

  3 and 4 show appropriate values of the dimension of the groove width ω of the groove 9. These figures are taken from the Heat Transfer Handbook (Japan Society of Mechanical Engineers, 1993). As shown in FIG. 3, the groove 9 has a groove width ω and a depth D in the flow direction. The main flow that flows above the groove 9 has a velocity U, and the boundary layer thickness at the upstream end of the groove 9 is δ. Under such conditions, referring to FIG. 4, it can be seen that the heat transfer at the bottom surface of the groove 9 is low when δ / ω = 0.28 or more. Therefore, as the groove width ω of the groove 9, the ratio of the boundary layer thickness δ to the groove width ω is 0.28 or more, preferably 0.28.

When the flying body 1 configured as described above performs high-speed flight, first, the low fiber density ablator 7 facing the mainstream MF is vaporized by aerodynamic heating. The vaporized ablation gas flows downstream and covers the outer surface S of the flying body 1 to prevent heat. Thereby, the low fiber density ablator portion 7 gradually disappears from the outer surface S side and forms a space on the outer surface S side in the groove 9.
On the other hand, the high density fiber ablator 5 does not vaporize as much as the low fiber density ablator 7, but generates ablation gas little by little. Thereby, the high fiber density ablator part 5 keeps holding an outer shape.

According to this embodiment, there exist the following effects.
The high fiber density ablator part 5 has a lower strength than the low fiber density ablator part 7 but has a lower vaporization rate of the ablator material. Therefore, a high fiber density ablator 5 is disposed on the outer surface S of the flying body 1. On the other hand, the low fiber density ablator part 7 is provided in the groove 9 formed in the high fiber density ablator part 7. Since the low fiber density ablator part 7 has a higher vaporization rate of the ablator material than the high fiber density ablator part 5, it can be vaporized even if it is provided in the groove 9 of the high fiber density ablator part 5. The ablation gas vaporized by the ablator material of the low fiber density ablator portion 7 can cover the outer surface S to prevent heat.

Since the entire surface on the outer surface S side of the groove 9 is open to the outer surface S, the low fiber density ablator portion 7 provided in the groove 9 faces the main flow MF flowing along the outer surface S. Thereby, it becomes easy to vaporize an ablator material, generation | occurrence | production of ablation gas can be accelerated | stimulated, and a heat-insulating effect can be improved.
Further, the groove 9 serves as a cavity, and vaporized ablation gas can stay in the groove to improve heat insulation.

Many low fiber density ablator parts 7 can be accommodated by making the longitudinal cross-sectional shape of the groove | channel 9 into a square.
The ratio of the mainstream boundary layer thickness δ to the groove width ω at the upstream end of the groove 9 is 0.28 or more, preferably 0.28. Thereby, since the heat transfer coefficient at the bottom surface of the groove 9 can be suppressed to be relatively low, vaporization of the low fiber density ablator portion 7 located at the groove bottom surface portion can be suppressed, and the strength can be maintained for a relatively long period of time. it can.
Of the plurality of grooves 9, the upstream side of the mainstream MF has a larger groove width, so that a large amount of ablation gas can be generated from the upstream side groove 9, and the heat insulation effect can be enhanced.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
This embodiment differs from the first embodiment in the shape of the groove, and the other points are the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 5, the longitudinal sectional shape of the groove 10 is a triangle. The entire bottom surface of the triangle opens to the outer surface S. Therefore, the groove width in the mainstream MF direction of the groove 10 is narrowed as it goes in the depth direction. Further, the groove width of the groove 10 is increased toward the upstream side of the mainstream MF.

According to this embodiment, there exist the following effects.
By making the longitudinal cross-sectional shape of the groove 10 triangular, an inclined surface can be formed at the edge of the outer surface S of the groove 10, so that separation of the flow of the main flow MF can be suppressed as much as possible.
Compared to the rectangular groove as in the first embodiment, there are fewer corners, so the number of stress concentration points is reduced, and the strength can be relatively increased.
The low fiber density ablator part 7 gradually disappears from the outer surface S side by the heat from the mainstream MF, but since the groove 10 has a triangular shape, the low fiber density ablator part 7 is exposed to the mainstream MF side. The surface area to be reduced becomes smaller as the ablator material is vaporized. Therefore, a high amount of ablation gas is generated at the beginning of flight to exhibit high heat insulation performance, and at the end of flight, the surface area of the low fiber density ablator part 7 is reduced, and the surface area of the high fiber density ablator part 5 is relatively increased. The strength can be kept high. Thus, it is effective for the flying body 1 that needs thermal protection in the early stage of flight.
In addition, the angle of each vertex of the triangle can be changed variously, and is adjusted according to the flight plan of the flying body 1.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
This embodiment is different from the above-described embodiments in the shape of the groove, and the other points are the same. Therefore, the same components as those in the above-described embodiments are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 6, the groove 11 is formed inside the high fiber density ablator 5 separated from the outer surface S. The longitudinal cross-sectional shape of the groove 11 is a square, and the groove width is increased toward the upstream side of the mainstream MF.

A hole 13 is formed between the groove 11 and the outer surface S, and the groove 11 communicates with the outer surface S side. The hole 13 is an elongated channel whose cross section is circular, for example, and is inclined toward the downstream side in the flow direction of the main flow MF. Specifically, the hole 13 has an acute inclination in the downstream direction with respect to the normal line of the outer surface S.
The upstream end (downward in the figure) of the hole 13 is connected to the upper surface (surface on the outer surface S side) of the groove 11. As shown in FIG. 7, the downstream end (upward in the drawing) of the hole portion 13 has a shape in which the cross-sectional area of the hole portion 13 gradually increases toward the downstream side in the flow direction of the main flow MF. In the same longitudinal section, the number of the holes 13 is two for the two grooves 11 from the upstream side of the main flow MF, and the number of the holes 13 is one for the third groove 11 from the upstream of the main flow MF. . However, the number of holes 13 is not particularly limited and can be set as appropriate. In addition, a plurality of holes 13 are also appropriately formed in the circumferential direction of the groove 11.
The groove 11 is provided with a low fiber density ablator 7, and the vaporized ablation gas is guided to the outer surface S through the hole 13.

According to this embodiment, there exist the following effects.
Since the groove 11 is formed inside the high fiber density ablator part 5 separated from the outer surface S, and the low fiber density ablator part 7 is disposed in the groove 11, the low fiber density mainly faces the mainstream MF. It can be set as the high fiber density ablator part 5 which is harder to vaporize than the ablator part 7, and the shape change of the outer surface S can be suppressed as much as possible.
The low fiber density ablator 7 provided in the groove 11 is heated and vaporized by heat input from the outer surface S. After the vaporized ablation gas is guided to the outer surface S through the hole 13 connecting the groove 11 and the outer surface S, the ablation gas can cover the outer surface and perform heat insulation.
Since the ablation gas stays inside the groove 11 after the low fiber density ablator 7 is vaporized, the heat insulation effect can be improved.
Since the hole 13 is inclined toward the downstream side in the flow direction of the main flow MF, the ablation gas can flow smoothly.
Further, the downstream side of the outer surface S of the hole 13 has a shape in which the flow path cross-sectional area of the hole 13 gradually increases toward the downstream side in the mainstream flow direction. Ablation gas can be guided over.

In addition, as shown in FIG. 8, only one groove 11 may be provided. The hole 13 may be connected to the downstream side surface of the main flow MF of the groove 11. As shown in FIG. 7, the shape of the hole 13 is such that the cross-sectional area of the channel gradually increases toward the downstream side in the flow direction of the main flow MF.
According to such a configuration, the tip side of the flying body 1 becomes high temperature due to heat input from the mainstream MF, and therefore, only one groove 11 is formed to remove the ablation gas from the low fiber density ablator 7 on the downstream side. Can lead to the surface. Thereby, the groove processing can be reduced, and the material cost of the low fiber density ablator portion 7 can be saved.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS.
This embodiment is different from the above-described embodiments in the shape of the groove, and the other points are the same. Therefore, the same components as those in the above-described embodiments are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 9A, the tip 1a of the flying body 1 has a tapered shape as in the above-described embodiments. And this flying body 1 is divided | segmented into half along the y-axis in the cross section shown in FIG.9 (b). In other words, the flying body 1 has a vertically divided structure.

FIG. 10 shows an enlarged view of a portion A shown in FIG. As shown in the figure, the joint part of the flying body 1 having a vertically split structure has a structure in which high fiber density ablator parts 5 are associated with each other in an inlay structure. Therefore, the joint portion has a stepped shape as shown in FIG. A gap 15 is formed on the mating surface of the joint.
Grooves 12 are formed in the protruding portions 5a constituting the stepped shape. The longitudinal cross-sectional shape of the groove | channel 12 is made into the rectangle, and the low fiber density ablator part 7 is provided in the groove | channel 12. The groove 12 communicates with the outer surface S through a gap 15 in the mating surface of the joint.

According to this embodiment, there exist the following effects.
Since the groove 12 is provided so as to communicate with the joint part where the high fiber density ablator parts 5 are connected to each other and the low fiber density ablator part 7 is disposed, the ablation gas vaporized in the groove 12 is grooved. 12 and the gap 15 on the mating surface of the joint portion, a heat insulation effect is obtained, and external high-temperature gas can be prevented from entering the flying body 1 through the gap 15 of the joint portion.

DESCRIPTION OF SYMBOLS 1 Ascending body 1a Tip part 3 Structural material 5 High fiber density ablator part 5a Projection part 7 Low fiber density ablator parts 9, 10, 11, 12 Groove 13 Hole part 15 Clearance L Longitudinal axis S Outer surface MF Mainstream

Claims (9)

A high fiber density ablator part provided on the outer surface side of the main body and having an ablator material mainly composed of a resin and a fiber matrix;
A low fiber density ablator part having a low fiber density than the ablator material of the high fiber density ablator part, and having an ablator material mainly composed of a resin and a fiber matrix;
With
A groove is formed in the high fiber density ablator part,
The low fiber density ablator part is provided in the groove,
The flying body according to claim 1, wherein the groove communicates with the outer surface.   The flying object according to claim 1, wherein an entire surface of the groove on the outer surface side is open to the outer surface.   The flying body according to claim 2, wherein a longitudinal cross-sectional shape of the groove viewed from a cut surface including a longitudinal axis of the main body is a quadrangle.   The flying body according to claim 2, wherein a longitudinal cross-sectional shape of the groove viewed from a cut surface including a longitudinal axis of the main body is a triangle.   The groove is formed in the high fiber density ablator part separated from the outer surface, and communicated by a hole part connecting the groove to the outer surface. Flying body.   The flying body according to claim 5, wherein the hole portion is inclined toward the downstream side in the mainstream flow direction. A plurality of the grooves are provided in the flow direction of the main flow that flows along the outer surface,
The flying object according to any one of claims 1 to 6, wherein a groove width of the groove in the flow direction of the mainstream is increased toward an upstream side of the mainstream.   The flying body according to any one of claims 1 to 6, wherein only one groove is provided in a flow direction of a main flow that flows along the outer surface.   The flying body according to claim 1, wherein the groove is provided so as to communicate with a joint portion where the high fiber density ablator portions are connected to each other.

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