Active and semi-active coupling thermal protection structure

Abstract

The invention relates to an active and semi-active coupling thermal protection structure, and belongs to the technical field of thermal protection of high-speed aircrafts. The active / semi-active coupling thermal protection structure comprises a dredging structure shell, a dredging structure capillary core, a dredging working medium, an active cooling pipeline, an active cooling working medium, an active cooling pipeline inlet and an active cooling pipeline outlet. A semi-active thermal protection structure represented by a dredging thermal protection structure is adopted to quickly transmit heat to the tail end of a front edge structure or a large-area area from local hot spot parts such as a sharp front edge and an overflow port, and then an active cooling structure represented by a fuel active cooling structure is adopted in a large-space area to achieve effective energy dissipation. A composite heat-proof structure combining an active cooling structure and a semi-active thermal protection structure is formed, and by means of huge heat sink provided by the active thermal protection structure, long-time strong heat dissipation capacity is provided for a dredging thermal protection structure, and the heat-proof performance is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal protection of high-speed aircraft, and in particular relates to an active and semi-active coupled thermal protection structure. Background Art

[0002] In recent years, the flight speed of high-speed aircraft has gradually increased, the aerodynamic heating of the leading edge of the aircraft has increased, and the operating temperature has become higher and higher, reaching or even exceeding the upper temperature limit of the existing thermal protection material system.

[0003] Conduit thermal protection is an important way to protect local high heat flux areas of high-speed aircraft. Unlike passive thermal protection, semi-active thermal protection is based on the idea of ​​active thermal management. It achieves rapid heat transfer or efficient heat dissipation through innovative structures, and can effectively solve the problem of non-ablative thermal protection in extreme environments. Conduit thermal protection developed in recent years is a typical innovative way to solve the problem of non-ablative thermal protection in local high heat flux areas. It is a semi-active thermal protection method that embodies the idea of ​​internal heat transfer and dissipation, and shows extremely high application potential.

[0004] The basic principle of the drainage type: based on the idea of ​​active heat management, it abandons the method of simple heat blocking and local consumption, and realizes the rapid transmission and efficient dissipation of the incoming heat through the internal working fluid phase change and transportation, which can significantly improve the system's heat protection ability. The drainage type thermal protection generally uses high-temperature heat pipes as a heat drainage channel, and its main heat dissipation method is radiation heat dissipation, which has the problem of insufficient heat dissipation capacity. Summary of the invention

[0005] The technical problem solved by the present application is: to overcome the shortcomings of the prior art, to provide an active and semi-active coupled thermal protection structure, to use a semi-active thermal protection structure represented by a drainage-type thermal protection structure to quickly transfer heat from local "hot spots" such as a sharp leading edge and an overflow port to the tail end of the leading edge structure or a large area, and then to use an active cooling structure represented by a fuel active cooling structure in a large space area to achieve effective energy dissipation, to form a composite thermal protection structure combining an active cooling structure and a semi-active thermal protection structure, and to rely on the huge heat sink provided by the active thermal protection structure to provide the drainage-type thermal protection structure with a long-term strong heat dissipation capability, thereby further improving the thermal protection performance.

[0006] In order to improve its ability to cope with extreme environments, this patent proposes an active / semi-active coupled thermal protection structure. Among them, the active thermal protection structure represented by the fuel active cooling structure extracts the heat inside the drainage structure through the flow of fuel, further reducing the overall temperature of the semi-active drainage structure.

[0007] The technical solutions provided by this application are as follows:

[0008] An active semi-active coupled thermal protection structure comprises a drainage structure shell, a drainage structure capillary core, a drainage working medium, an active cooling pipe and an active cooling working medium. The interior of the drainage structure shell is a closed space. The drainage structure capillary core covers the entire inner wall of the drainage structure shell. The drainage structure capillary core has a porous capillary structure. The drainage working medium is in the porous capillary structure of the drainage structure capillary core. Both ends of the active cooling pipe are located outside the drainage structure shell, the middle part of the active cooling pipe extends into the interior of the drainage structure shell, and the active cooling working medium performs unidirectional movement in the active cooling pipe.

[0009] The housing of the drainage structure is made of high-temperature alloy.

[0010] The porous capillary structure of the capillary core of the drainage structure is formed by screen weaving, sintering or 3D printing.

[0011] The diversion working medium is an alkali metal.

[0012] The middle portion of the active cooling pipe is located inside the drainage structure in the form of a coil.

[0013] The active cooling medium is fuel oil or water.

[0014] The two ends of the active cooling pipeline located outside the casing of the drainage structure are respectively an active cooling pipeline inlet and an active cooling pipeline outlet, and the active cooling pipeline inlet and the active cooling pipeline outlet are connected to an external circulation cooling system.

[0015] In summary, this application at least includes the following beneficial technical effects:

[0016] 1. High heat protection capability. The composite heat protection structure combining active cooling structure and semi-active heat protection structure can meet the leading edge heat protection requirements in extreme environments.

[0017] 2. Good designability. The drainage medium and active cooling medium can be changed according to the actual thermal environment of the leading edge, and the design range is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of an active and semi-active coupled thermal protection structure;

[0019] Figure 2 Embodiment calculation model;

[0020] Figure 3 Temperature field distribution results when the fuel flow rate is 0g / s;

[0021] Figure 4 Temperature field distribution results when the fuel flow rate is 5g / s;

[0022] Figure 5 Temperature field distribution results when the fuel flow rate is 10g / s. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] like Figure 1 As shown, the embodiment of the present application provides an active / semi-active coupled thermal protection structure, including a drainage structure shell 1, a drainage structure capillary core 2, a drainage medium 3, an active cooling pipe 4, an active cooling medium 5, an active cooling pipe inlet 6, and an active cooling pipe outlet 7. Among them, the drainage structure shell 1 is a part of the leading edge structure of the aircraft, and one end of the drainage structure shell 1 is a tip. The interior of the drainage structure shell 1 is a closed space, the drainage structure capillary core 2 is closely connected to the inner wall of the drainage structure shell 1, the drainage structure medium 3 is inside the drainage structure capillary core 2, the active cooling pipe 4 is located inside the drainage structure shell 1 in the form of a coil, and the two ends of the active cooling pipe 4 are located outside the drainage structure shell 1 and form an active cooling pipe inlet 6 and an active cooling pipe outlet 7, and the active cooling medium 5 moves unidirectionally in the active cooling pipe 4.

[0025] During operation, the drainage structure shell 1 is heated and the temperature of the tip part (i.e., the stagnation point) is the highest, and the drainage working fluid 3 in the capillary core 2 of the drainage structure is heated and vaporized to become the drainage working fluid 3 gas; at the same time, the cooling medium enters the active cooling pipe 4 through the active cooling pipe inlet 6, takes away the heat inside the drainage structure, and leaves the active cooling pipe 4 through the active cooling pipe outlet 7, thereby realizing the heat transfer inside the drainage structure. After the drainage working fluid 3 gas contacts the surface of the active cooling pipe 4, heat exchange occurs, and the drainage working fluid 3 gas is cooled and liquefied into drainage working fluid 3 liquid and falls back to the surface of the drainage structure capillary core 2. Through the capillary action of the drainage structure capillary core 2, the drainage working fluid 3 liquid is sucked to the tip position of the drainage structure shell 1, and the above-mentioned drainage working fluid 3 gasification-liquefaction-liquid redistribution cycle process under capillary action is repeated. In this process, the heat circulation of the high-temperature part is brought to the entire internal space of the drainage structure shell 1 by the drainage working fluid 3 gas, so that the heat distribution is uniform. At the same time, the active cooling pipe 4 continues to take out the heat, thereby achieving the heat of the drainage structure shell 1 being taken away and the heat being uniform.

[0026] The housing 1 of the drainage structure is made of high-temperature alloy, and its shape includes but is not limited to wedge-shaped, conical or special-shaped, and the minimum leading edge radius can be up to millimeter level.

[0027] The drainage structure shell 1 is formed into a hollow enclosed space by welding or 3D printing, preferably 3D printing.

[0028] The capillary core 2 of the drainage structure is formed into a porous capillary structure by screen weaving, sintering or 3D printing, preferably by 3D printing.

[0029] The working medium 3 of the drainage structure is an alkali metal.

[0030] The active cooling pipe 4 is located inside the drainage structure in the form of a coil. The material is a high-temperature alloy. The pipe diameter, length, coil form, etc. are determined according to actual conditions.

[0031] The active cooling medium 5 moves in one direction inside the active cooling pipe 4 .

[0032] The active cooling medium 5 can be fuel, water or other cooling medium, preferably fuel.

[0033] The active cooling pipe inlet 6 and the active cooling pipe outlet 7 are connected to the external circulation cooling system. If the active cooling medium 5 is fuel, it can also directly enter the combustion chamber.

[0034] Example

[0035] In order to illustrate the feasibility of this method, we designed an active / semi-active coupled thermal protection structure and calculated its active cooling performance. The relevant parameters are set as follows: The active / semi-active coupled thermal protection structure includes a drainage structure shell, a drainage structure capillary core, a drainage working fluid, an active cooling pipeline, an active cooling working fluid, an active cooling pipeline inlet, and an active cooling pipeline outlet. Among them, the interior of the drainage structure is a closed space, the drainage structure capillary core is closely connected to the drainage structure shell, the drainage structure working fluid is inside the drainage structure capillary core, the active cooling pipeline is located inside the drainage structure in the form of a coil, and the active cooling working fluid moves unidirectionally in the active cooling pipeline. When working, it enters the active cooling pipeline through the active cooling pipeline inlet, takes away the heat inside the drainage structure, and leaves the active cooling pipeline through the active cooling pipeline outlet, thereby realizing heat transfer inside the drainage structure.

[0036] In this embodiment, the casing of the drainage structure is made of nickel-based high-temperature alloy, sodium is selected as the drainage medium, the fuel cooling pipe is made of nickel-based high-temperature alloy material, and fuel is selected as the active cooling medium. The calculation model is as follows: Figure 2 The working principle is as follows: in the working state, the stagnation point and large area of ​​the drainage structure are heated, and the heat is transferred from the stagnation point area to the inside of the heat pipe cavity, the drainage working medium evaporates and gradually starts to work, the local high-heated stagnation point is the evaporation point, the local low-heated part and the fuel pipeline are the condensation part, and the steam in the cavity transfers the heat of the local high heat flow part to the local low heat flow part and the surface of the fuel pipeline through convection and phase change heat transfer, so that the entire heat protection structure is isothermal, and the heat is effectively dissipated by cooling the fuel, reducing the thermal protection pressure of the sharp leading edge stagnation point area and improving the thermal protection performance.

[0037] Figure 3The temperature field distribution result when the fuel flow rate is 0g / s, that is, there is no active fuel cooling, pure drainage semi-active cooling scheme, Figure 4 and Figure 5 These are the results when the flow rate is 5g / s and 10g / s, that is, the active / semi-active composite scheme. In the pure diversion scheme, relying on the rapid heat transfer characteristics of the heat pipe, the stagnation temperature is about 1600℃, and the tail cover is 1000℃. After adding fuel active cooling, the stagnation temperature is significantly reduced to 1200℃, and the tail cover also has a significant decrease to varying degrees, which is specifically related to the fuel flow rate. Correspondingly, the stagnation temperature of the non-drainage scheme is about 1871℃, and the cooling efficiency of the diversion fuel cooling composite scheme is 36%.

[0038] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0039] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. An active and semi-active coupled thermal protection structure, characterized in that: The invention comprises a drainage structure shell (1), a drainage structure capillary core (2), a drainage working medium (3), an active cooling pipe (4) and an active cooling working medium (5); the interior of the drainage structure shell (1) is a closed space; the drainage structure capillary core (2) covers the entire inner wall of the drainage structure shell (1) and is tightly connected thereto; the drainage structure capillary core (2) has a porous capillary structure; the drainage working medium (3) is in the porous capillary structure of the drainage structure capillary core (2); both ends of the active cooling pipe (4) are located outside the drainage structure shell (1); the middle part of the active cooling pipe (4) extends into the interior of the drainage structure shell (1); and the active cooling working medium (5) moves unidirectionally in the active cooling pipe (4).

2. The active and semi-active coupled thermal protection structure according to claim 1, characterized in that: The drainage structure shell (1) is made of high-temperature alloy.

3. The active and semi-active coupled thermal protection structure according to claim 1, characterized in that: The porous capillary structure of the drainage structure capillary core (2) is formed by screen weaving, sintering or 3D printing.

4. The active and semi-active coupled thermal protection structure according to claim 1, characterized in that: The drainage working medium (3) is an alkali metal.

5. The active and semi-active coupled thermal protection structure according to claim 1, characterized in that: The middle part of the active cooling pipe (4) is located inside the drainage structure in the form of a coil.

6. The active and semi-active coupled thermal protection structure according to claim 1, characterized in that: The active cooling medium (5) is fuel oil or water.

7. The active and semi-active coupled thermal protection structure according to claim 1, characterized in that: The two ends of the active cooling pipe (4) located outside the drainage structure shell (1) are respectively an active cooling pipe inlet (6) and an active cooling pipe outlet (7), and the active cooling pipe inlet (6) and the active cooling pipe outlet (7) are connected to an external circulation cooling system.

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