Multiplex heat shield for the bottom of a rocket substage

Abstract

The utility model provides a kind of multiplex heat protection device for rocket substage bottom, including heat-absorbing plate and heat-blocking plate, the heat-absorbing plate is fixed in the side of heat-blocking plate, and heat-blocking cavity is formed between the heat-blocking plate and the heat-absorbing plate, the heat-absorbing plate includes substrate, coating and heat radiation heat-blocking layer;The coating is arranged in the first surface of substrate, for absorbing heat when rocket flies;The heat radiation heat-blocking layer is arranged in the second surface of substrate, for reducing the heat radiation exchange amount between heat-absorbing plate and heat-blocking plate when rocket flies;The first surface and the second surface are the surface of the heat-absorbing plate each other opposite surface. Heat-absorbing plate can be replaced, repeatedly used for rocket launch, to reduce the purpose of cost.

Description

Technical Field

[0001] This utility model belongs to the field of rocket technology, and in particular relates to a reusable thermal protection device for the bottom of the first stage of a rocket. Background Technology

[0002] In recent decades, launch vehicle design and improvements have primarily focused on requirements such as high efficiency and high reliability. The adoption of reusable designs has significantly reduced space launch costs and has guided the technological development direction of the launch vehicle field. Countries and related companies have recognized that simply modifying existing expendable rockets using existing technological approaches is no longer sufficient for future needs. Reusable design has become a key technological feature of next-generation launch vehicles.

[0003] Currently, reusable rockets are partially reusable, meaning that after the first stage returns to Earth, it is inspected and then launched again. To increase payload capacity, the first stage often uses multiple engines in parallel. When multiple engines operate in parallel, the exhaust gases from the main engine and boosters shear and mix with each other, forming a complex flow field structure. This interference leads to uneven heat distribution in the bottom region, creating localized high-temperature areas. During the first stage's reentry, the interaction between the engine exhaust and the incoming airflow results in a significantly higher heat flux at the bottom of the reentry phase compared to the ascent phase.

[0004] Currently, heat protection at the bottom of the first stage of a rocket is based on the principle of ablation. When the jet impacts and radiates onto the surface of the heat absorber, high-temperature ablation occurs, carrying away a large amount of heat. Therefore, selecting an appropriate heat absorber thickness can ensure that the temperature on the back of the heat absorber remains below 110°C. However, such heat absorbers are expensive. For expendable rockets, the heat absorbers will burn up during reentry. But for reusable rockets, if such expendable heat absorbers are still used, they need to be completely removed and replaced with new heat absorbers after the first stage returns, increasing the reuse cost of reusable rockets. Utility Model Content

[0005] In view of the problems existing in the prior art, this utility model provides a reusable thermal protection device for the bottom of the first stage of a rocket, which at least partially solves the problem of high cost in the prior art.

[0006] This disclosure provides a reusable thermal protection device for the bottom of a rocket first stage, including a heat-absorbing plate and a heat-resistant plate. The heat-absorbing plate is fixed to one side of the heat-resistant plate, and a heat-resistant cavity is formed between the heat-resistant plate and the heat-absorbing plate. The heat-absorbing plate includes a substrate, a coating, and a heat radiation blocking layer; the coating is disposed on a first surface of the substrate and is used to absorb heat during rocket flight; the heat radiation blocking layer is disposed on a second surface of the substrate and is used to reduce the amount of heat radiation exchange between the heat-absorbing plate and the heat blocking plate during rocket flight; the first surface and the second surface are the surfaces of the heat-absorbing plate that are opposite to each other.

[0007] Optionally, the surface of the heat-insulating plate facing the heat-absorbing plate is covered with a heat radiation-insulating layer.

[0008] Optionally, the heat-insulating plate is a glass fiber composite plate.

[0009] Optionally, the heat-insulating plate has a groove on the side facing the heat-absorbing plate, and the groove area has vents that penetrate both sides of the heat-insulating plate in the thickness direction and communicate with the groove.

[0010] Optionally, the diameter of the pores is 1.5~2.5mm, multiple pores are arranged in an array, the spacing between adjacent pores is 15mm, and the porosity of the heat-insulating plate in its groove area is 0.73%.

[0011] Optionally, a protruding heat-resistant pad is provided on the surface of the heat-resistant plate facing the heat-absorbing plate. The heat-resistant pad, the heat-resistant plate, and the heat-absorbing plate form the heat-resistant cavity in the groove. An installation component is provided inside the heat-resistant pad for installing the heat-absorbing plate.

[0012] Optionally, it also includes a structural crossbeam for mounting the protective device onto the rocket.

[0013] Optionally, the coating is an ablation-type heat-resistant coating, the substrate is a composite phenolic substrate, and the heat radiation insulation layer is stainless steel foil.

[0014] Optionally, the thickness of the composite phenolic substrate is 3~5mm, the thickness of the ablation-type heat-resistant coating is 3~6mm, and the thickness of the stainless steel foil is 0.05mm.

[0015] The present invention provides a reusable thermal protection device for the bottom of the first stage of a rocket. The heat-absorbing plate of the reusable thermal protection device for the bottom of the first stage of a rocket is set on the heat-insulating plate. After the rocket is recovered, the heat-absorbing plate can be disassembled and replaced for the next rocket launch, thereby achieving the purpose of reducing costs. Attached Figure Description

[0016] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0017] Figure 1 A schematic diagram of the structure of a reusable thermal protection device for the bottom of a rocket first stage provided in an embodiment of this disclosure; Among them, 1-coating; 2-substrate; 3-stainless steel foil; 4-heat-insulating plate; 5-structural beam; 6-pore; 7-groove; 8-heat-insulating pad. Detailed Implementation

[0018] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0019] It should be understood that the following specific examples illustrate the implementation of this disclosure, and those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0020] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways.

[0021] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The illustrations only show the components related to this disclosure and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0022] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0023] like Figure 1 As shown, this embodiment discloses a reusable thermal protection device for the bottom of the first stage of a rocket, including a heat-absorbing plate and a heat-blocking plate 4. The heat-absorbing plate is fixed to one side of the heat-blocking plate 4, and a heat-blocking cavity is formed between the heat-blocking plate 4 and the heat-absorbing plate. When the rocket is in flight, the heat-absorbing plate absorbs and isolates heat. After the rocket is recovered, the heat-absorbing plate is replaced and can be used for the next rocket launch. The heat-insulating cavity formed between the heat-insulating plate and the heat-absorbing plate is connected to the atmospheric environment. The gas in the heat-insulating cavity isolates the heat, thereby reducing the heat transferred to the heat-insulating plate and preventing the high temperature outside the rocket from damaging the heat-insulating plate.

[0024] The heat-absorbing plate includes a substrate 2, a coating 1, and a heat radiation blocking layer. The coating 1 is disposed on a first surface of the substrate 2 and is used to absorb heat during rocket flight. The heat radiation blocking layer is disposed on a second surface of the substrate 2 and is used to reduce the amount of heat radiation exchange between the heat-absorbing plate and the heat-blocking plate 4 during rocket flight. The first and second surfaces are arranged opposite to each other; the first and second surfaces are the surfaces of the heat-absorbing plate that are opposite to each other.

[0025] The surface of the heat-insulating plate 4 facing the heat-absorbing plate is covered with a heat radiation insulating layer. The heat-insulating plate 4 is a glass fiber composite board. A groove 7 is provided on the side of the heat-insulating plate facing the heat-absorbing plate, and air holes 6 are formed in the groove 7, penetrating both sides of the heat-insulating plate along its thickness direction and communicating with the groove. During rocket flight, the groove 7 is filled with air, which insulates against heat, and the air holes 6 reduce the pressure difference between the inside and outside of the groove 7. The diameter of the air holes 6 is 1.5~2.5mm, and multiple air holes 6 are arranged in an array with a spacing of 15mm between adjacent air holes 6. The porosity of the heat-insulating plate 4 in the groove 7 area is 0.73%.

[0026] A protruding heat-resistant pad 8 is provided on the surface of the heat-resistant plate 4 facing the heat-absorbing plate. The heat-resistant pad 8, the heat-resistant plate 4 and the heat-absorbing plate form the heat-resistant cavity in the groove 7. An installation component is provided in the heat-resistant pad 8, and the installation component is used to install the heat-absorbing plate.

[0027] The device also includes a structural beam 5, which is used to mount the protective device onto the rocket. The heat shield 4 is mounted to the structural beam 5 with bolts.

[0028] In a specific application, the heat shield plate 4 is located on top of the heat absorber plate. The heat shield plate 4 has a flat structure, and its surface facing the heat absorber plate has protruding heat shield pads 8. The heat shield pads 8 and the heat shield plate 4 are manufactured as a single unit. The heat shield pads 8 contain bolt mounting blocks for bolt fastening to the heat absorber plate. The height of the heat shield pads 8 is 8~12mm. Stainless steel foil 3 is adhered to the opposing surfaces of the heat shield plate 4 and the heat absorber plate.

[0029] Coating 1 is an ablation-type heat-resistant coating, substrate 2 is a composite phenolic substrate, and the heat radiation insulating layer is stainless steel foil 3. The thickness of the composite phenolic substrate is 3-5 mm, and the thickness can be 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc. The thickness of the ablation-type heat-resistant coating is 3-6 mm, and the thickness can be 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, etc. The stainless steel foil 3 is 0.05 mm thick. The stainless steel foil 3 is bonded to the back of the composite phenolic substrate (i.e., the second surface mentioned above) using high-temperature adhesive. In a specific embodiment, the thickness of the composite phenolic substrate is 3 mm, the thickness of the ablation-type heat-resistant coating is 4 mm, and the thickness of the stainless steel foil 3 is 0.05 mm. This embodiment is a preferred cost solution that satisfies high-temperature protection during rocket launch.

[0030] In one specific application, the substrate 2 is coated with an ablation-type heat-resistant coating, and a stainless steel foil 3 is adhered to its inner surface (i.e., the second surface of the substrate facing the heat shield). The stainless steel foil 3 is used to reduce heat radiation exchange. The heat shield 4 is made of a material with low thermal conductivity and is bolted to the substrate 2. The heat shield 4 is also bolted to the structural beam 5. Air inlet and outlet holes 6 are provided on the heat shield 4 to reduce the internal and external pressure difference. Stainless steel foil 3 is also adhered to the surface of the heat shield 4 adjacent to the heat absorber to further reduce heat radiation exchange.

[0031] During the entire flight of the first stage of the rocket, the first stage of heat protection is provided by the substrate 2 and the coating 1. After absorbing the heat flow, the coating 1 begins to ablate and decompose, thereby reducing the heat flow transferred to the substrate 2. After the substrate 2 is heated, the heat radiation is transferred to the surrounding structure. The heat radiation insulation layer provided on the second surface of the substrate 2 reduces the amount of heat radiation exchange. After the first stage of the rocket is recovered, the heat absorber is removed and replaced with a new one for the next flight launch mission.

[0032] This embodiment achieves graded thermal protection, forming two levels of protection at the bottom of the first stage. First, a heat-absorbing plate provides the first level of thermal protection, creating a high-temperature zone. Then, a heat-resistant plate further reduces the temperature of this zone. Simultaneously, the gas within the heat-resistant cavity isolates the temperature, and the low thermal conductivity of the heat-resistant plate itself further lowers the temperature to below 110°C. The heat-absorbing plate is disassembled and replaced after the first stage reentries, resulting in higher efficiency. The ablated heat-absorbing plate is then coated for reuse, achieving a reusable thermal protection system at the bottom of the first stage.

[0033] The first stage of the rocket's flight includes the ascent and reentry phases. First-stage heat protection relies on the substrate 2 and its ablative heat-resistant coating. The ablative coating absorbs heat and then undergoes ablation, reducing the heat transfer to the substrate 2. After heating up, the substrate 2 emits high-temperature thermal radiation, primarily transferred to surrounding structures such as the heat shield 4. Because stainless steel foil 3 is adhered to the surfaces of both the substrate 2 and the heat shield 4, the amount of heat radiation exchange is reduced, resulting in less heat transfer compared to solid-state heat conduction. During the ascent and reentry of the first stage, the air within the groove 7 further isolates the heat. The pressure difference between the inside and outside of the groove 7 is regulated by the air intake and exhaust ports 6.

[0034] After the first stage of the launch vehicle is recovered, the heat absorber plates are removed. Since heat shield 4 absorbs little heat, it will not suffer structural ablation damage. Only a new heat absorber plate needs to be replaced and reassembled to form a new first-stage bottom heat absorber plate for the next launch mission. The old heat absorber plates, after removing any remaining ablation-resistant thermal protection coating, can be recoated with a new ablation-resistant thermal protection coating and used on other recovered first stages for further rocket launches.

[0035] Compared to existing first-stage bottom heat absorbers, the thermal protection device in this embodiment utilizes the characteristic that thermal radiation has a smaller heat flux than solid-state heat transfer. It employs graded thermal protection based on the temperature tolerance of the heat-resistant materials, dividing the protection range into high-temperature and medium-temperature zones. High-temperature thermal protection is achieved using heat absorbers and an ablative thermal coating applied to the surface, while medium-temperature thermal protection is achieved using heat-insulating plates 4. The high-temperature and medium-temperature thermal protection zones are separated by a thermal radiation insulating layer. After the rocket reentries, only the heat absorbers in the high-temperature thermal protection zone need to be replaced.

[0036] The thermal protection device in this embodiment utilizes the gradual temperature change from high to low at the bottom of the rocket's first stage thermal protection system, dividing it into high-temperature and medium-temperature thermal protection zones. For reusable rockets, only the high-temperature ablation parts need to be replaced, abandoning the conventional rocket's overall bottom heat absorption plate solution. This aligns with the flight and operational characteristics of reusable rockets, reducing the reuse cost and assembly time of reusable rockets.

[0037] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0038] In this disclosure, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0039] Additionally, as used herein, the "or" used in a list of items beginning with "at least one" indicates a separate list, such that a list of, for example, "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word "exemplary" does not imply that the described example is preferred or better than other examples.

[0040] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0041] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A reusable thermal protection device for the bottom of a rocket first stage, characterized in that, It includes a heat-absorbing plate and a heat-resistant plate, wherein the heat-absorbing plate is fixed to one side of the heat-resistant plate, and a heat-resistant cavity is formed between the heat-resistant plate and the heat-absorbing plate; The heat-absorbing plate includes a substrate, a coating, and a heat radiation blocking layer; the coating is disposed on a first surface of the substrate and is used to absorb heat during rocket flight; the heat radiation blocking layer is disposed on a second surface of the substrate and is used to reduce the amount of heat radiation exchange between the heat-absorbing plate and the heat blocking plate during rocket flight; the first surface and the second surface are the surfaces of the heat-absorbing plate that are opposite to each other.

2. The reusable thermal protection device for the bottom of the first stage of a rocket according to claim 1, characterized in that, The surface of the heat-insulating plate facing the heat-absorbing plate is covered with a heat radiation-insulating layer.

3. The reusable thermal protection device for the bottom of the first stage of a rocket according to claim 2, characterized in that, The heat-insulating plate is a glass fiber composite plate.

4. The reusable thermal protection device for the bottom of the first stage of a rocket according to claim 1, characterized in that, The heat-insulating plate has a groove on the side facing the heat-absorbing plate, and the groove area has air holes that penetrate both sides of the heat-insulating plate in the thickness direction and communicate with the groove.

5. The reusable thermal protection device for the bottom of the first stage of a rocket according to claim 4, characterized in that, The diameter of the pores is 1.5~2.5mm, and multiple pores are arranged in an array with a spacing of 15mm between adjacent pores. The porosity of the heat-insulating plate in its groove area is 0.73%.

6. The reusable thermal protection device for the bottom of the first stage of a rocket according to claim 4, characterized in that, A protruding heat-resistant pad is provided on the surface of the heat-resistant plate facing the heat-absorbing plate. The heat-resistant pad, the heat-resistant plate, and the heat-absorbing plate form the heat-resistant cavity in the groove. An installation component is provided in the heat-resistant pad, and the installation component is used to install the heat-absorbing plate.

7. The reusable thermal protection device for the bottom of a rocket first stage according to claim 1, characterized in that, It also includes structural beams for mounting protective devices onto the rocket.

8. The reusable thermal protection device for the bottom of a rocket first stage according to claim 1, characterized in that, The coating is an ablation-type heat-resistant coating, the substrate is a composite phenolic substrate, and the heat radiation insulation layer is stainless steel foil.

9. The reusable thermal protection device for the bottom of the first stage of a rocket according to claim 8, characterized in that, The thickness of the composite phenolic substrate is 3~5mm, the thickness of the ablation-type heat-resistant coating is 3~6mm, and the thickness of the stainless steel foil is 0.05mm.

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