Active thermal protection system based on composite channel structure
By combining phase change heat transfer with controllable jet cooling through a composite channel structure, the thermal protection problem of high-speed aircraft under different aerodynamic heating conditions is solved, and flexible adjustment of cooling performance and reduction of working fluid consumption are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 浣江实验室
- Filing Date
- 2023-11-18
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies are insufficient to effectively adjust cooling modes at different flight stages, failing to meet the thermal protection requirements of high-speed aircraft under extreme aerodynamic heating conditions, and also resulting in significant coolant consumption.
An active thermal protection system based on a composite channel structure was designed, which combines phase change heat transfer and controllable jet cooling modes. By arranging phase change heat transfer microchannels and gas delivery microchannels in a cross pattern, the system achieves a combination of internal cooling and external jet cooling, allowing for flexible adjustment of cooling performance.
It achieves efficient thermal protection under different aerodynamic and thermal conditions, reduces the consumption of cooling working fluid, and improves the flexibility and stability of cooling performance.
Smart Images
Figure CN118083110B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of thermal protection technology for high-speed aircraft, and more specifically, to an active thermal protection system based on a composite channel structure. Background Technology
[0002] When an aircraft flies at hypersonic speeds for extended periods within the dense atmosphere, the temperature of its outer surface can reach or approach 3000 degrees Celsius due to aerodynamic heating. To ensure the aircraft's fuselage and internal environment operate normally within permissible temperature ranges, effective structural thermal protection design is necessary. The thermal protection requirements for critical components of the aircraft continuously change throughout the flight process with variations in parameters such as altitude and speed. Therefore, designing an efficient and rational active thermal protection scheme is of great significance to the development of hypersonic aircraft.
[0003] CN107150810A discloses a protection system for thermal components of an aircraft. This system utilizes cooling water for single-phase convective cooling of the aircraft's thermal components. After heating, the cooling water undergoes flash evaporation to separate into liquid water and water vapor. The liquid water returns to the circulation pipeline, while the water vapor is used for film cooling of other thermal components. This solution employs internal cooling and external film cooling for different aircraft thermal components, but lacks consideration for thermal protection of components subjected to extreme aerodynamic heating and for the significant variations in thermal protection requirements for the same thermal component during cross-domain flight. Under extreme aerodynamic heating conditions, a combination of internal cooling and external jet cooling is needed to ensure the safety of thermal components. Furthermore, during cross-domain flight, the same thermal component requires different thermal protection technologies under different thermal environments to achieve thermal protection while minimizing coolant consumption. Therefore, a thermal protection system and thermal protection structure with an adjustable cooling mode are needed to address these issues.
[0004] Under low to medium aerodynamic heating conditions, convection cooling is a suitable active thermal protection technology. It utilizes the convective heat transfer of the cooling medium within the internal piping of the thermal protection structure to achieve cooling. Under low heat flux conditions, the one-way convective heat transfer of the cooling medium can meet the thermal protection requirements. Under medium to high heat flux conditions, the cooling medium flows and boils within the channels, and the phase change endothermic energy of the cooling medium further enhances the thermal protection performance.
[0005] Under high heat flux conditions, convection cooling alone is insufficient to meet thermal protection requirements. More efficient evaporative cooling is needed to achieve effective thermal protection in high heat flux regions. Evaporative cooling utilizes a cooling medium injected through micropores in the wall into the near-wall region of the external flow field, forming a cooling gas film that alters the near-wall flow field. This reduces the input of aerodynamic heat and, to some extent, improves the stability of the cooling medium's flow boiling, achieving more efficient thermal protection. However, another difference between evaporative cooling and internal convection cooling is that evaporative cooling is an open system; the cooling medium enters the external flow field, resulting in its consumption.
[0006] Addressing the thermal protection needs of aircraft at different flight stages, and combining the characteristics and thermal protection performance of convection cooling and evaporative cooling, it is of significant engineering importance to develop a highly efficient and reasonable active thermal protection system for high-speed aircraft by integrating these two thermal protection technologies. Summary of the Invention
[0007] This invention addresses the thermal protection requirements of high-speed aircraft by designing an active thermal protection system that simultaneously incorporates phase change heat transfer and controllable jet cooling.
[0008] The technical solution of the present invention is as follows:
[0009] An active thermal protection system based on a composite channel structure includes a liquid storage tank, a flow pump, a filter, a composite channel thermal protection structure, a gas-liquid separator, and a gas storage tank. The liquid storage tank, flow pump, filter, composite channel thermal protection structure, and gas-liquid separator are sequentially connected in a loop. Another path of the gas-liquid separator is connected to the composite channel thermal protection structure via the gas storage tank. A connection is provided between the gas storage tank and the composite channel thermal protection structure. second A regulating valve is installed between the liquid storage tank and the flow pump. First A shut-off valve; a back pressure valve is installed between the composite channel thermal protection structure and the gas-liquid separator; a gas-liquid separator is installed between the gas-liquid separator and the gas storage tank. No. one One-way valve; a valve is installed between the liquid storage tank and the gas-liquid separator. second One-way valve; First The regulating valve, the insulated pipeline, and the shut-off valve are connected in sequence to form a bypass between the back pressure valve and the gas storage tank; the gas storage tank is equipped with an insulated pipeline and a temperature-controlled heating belt.
[0010] The composite channel thermal protection structure comprises two parts: a phase change heat transfer channel array and a gas delivery channel array. The phase change heat transfer channel array is composed of a liquid inlet, a primary liquid distribution chamber, a liquid distribution hole, a secondary liquid distribution chamber, a phase change heat transfer microchannel, a collection chamber, and an outlet connected in sequence. The gas delivery channel array is composed of a gas inlet, a primary gas distribution chamber, a gas distribution hole, a secondary gas distribution chamber, a gas delivery microchannel, and a micropore array connected in sequence.
[0011] The liquid inlet of the composite channel thermal protection structure is connected to the filter, the outlet is connected to the back pressure valve, and the gas inlet is connected to... second The regulating valve is connected.
[0012] The aforementioned heat-insulating pipes and temperature-controlled heating strips are wrapped around the outer surface of the gas storage tank.
[0013] The composite channel thermal protection structure is arranged on the wall surface of the high-speed aircraft that requires thermal protection, and its outer surface is part of the aircraft wall surface.
[0014] The active thermal protection system based on the composite channel structure operates as follows: The system consists of a main loop and a gas branch. The liquid cooling medium in the main loop's storage tank is delivered by a flow pump and filtered for fine impurities via a first shut-off valve. It then enters the phase change heat exchange microchannel in the composite channel thermal protection structure, where it cools the thermal protection structure through phase change boiling heat exchange. The gas-liquid two-phase mixture after heat exchange passes through a back pressure valve. Part of it directly enters the gas-liquid separator, while the other part enters the insulation pipeline through a first regulating valve and then returns to the main loop through a second shut-off valve to enter the gas-liquid separator. The liquid cooling medium obtained by the gas-liquid separator flows back to the storage tank via a second one-way valve.
[0015] The gaseous working fluid transported by the gas branch is obtained by separating the gas and liquid two-phase mixture by a gas-liquid separator. The gaseous working fluid enters the gas storage tank through the first one-way valve, and the second regulating valve regulates the flow rate of the gaseous working fluid entering the composite channel thermal protection structure. The gaseous working fluid is transported in the gas transport microchannel in the composite channel thermal protection structure, and is injected into the near-wall flow field of the aircraft's external flow field in the form of micro-jet through the micro-hole array on the channel wall, changing the velocity and temperature boundary layer distribution in the near-wall region and reducing the wall heat flux.
[0016] The active thermal protection system based on the composite channel structure first insulates the gas tank by wrapping the gas tank with an insulated pipe to maintain a certain gas source pressure in order to maintain the gas pressure required for the micro-jet. When the temperature of the gas tank is difficult to reach the gas pressure requirement, the system uses electric heating to control the temperature and regulate the jet gas source pressure.
[0017] The phase change heat transfer microchannel and the gas transport microchannel in the composite channel thermal protection structure are not interconnected, and are arranged in a cross pattern.
[0018] This invention has the advantages of excellent cooling performance and flexible and adjustable cooling modes, which can meet the thermal protection requirements of high-speed aircraft for long-term cross-domain navigation. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the active thermal protection system based on a composite channel structure according to the present invention;
[0020] In the figure, there are: liquid storage tank 1, first shut-off valve 21, flow pump 2, filter 3, composite channel thermal protection structure 4, back pressure valve 22, first regulating valve 23, heat-insulated pipeline 7, second shut-off valve 24, gas-liquid separator 5, first check valve 25, second check valve 26, gas storage tank 6, second regulating valve 27, composite channel thermal protection structure 4, and temperature-controlled heating belt 8.
[0021] Figure 2 This is a schematic diagram of a microjet flow in a composite channel thermal protection structure.
[0022] In the figure, the micropore array is 4.9, and the arrow indicates the direction of the microjet flow.
[0023] Figure 3 The bottom surface of the composite channel thermal protection structure;
[0024] In the diagram, the liquid inlet is 4.1, the outlet is 4.5, and the gas inlet is 4.6.
[0025] Figure 4 The outer surface of the composite channel thermal protection structure;
[0026] The micropore array in the figure is 4.9.
[0027] Figure 5 This is a schematic diagram of the phase transformation heat transfer channel cross-section and flow of the composite channel thermal protection structure;
[0028] In the figure, the primary liquid distribution chamber is 4.2, the liquid distribution hole is 4.3, the secondary liquid distribution chamber is 4.12, the phase change heat transfer microchannel is 4.4, the collection chamber is 4.10, the primary gas distribution chamber is 4.11, the secondary gas distribution chamber is 4.13, and the black arrows indicate the direction of working fluid flow.
[0029] Figure 6 This is a schematic diagram of the cross-section and flow of the gas delivery channel in the composite channel thermal protection structure.
[0030] In the diagram, the liquid inlet is 4.1, the outlet is 4.5, the primary liquid distribution chamber is 4.2, the collection chamber is 4.10, the gas inlet is 4.6, the primary gas distribution chamber is 4.11, the gas distribution hole is 4.7, the secondary gas distribution chamber is 4.13, the gas delivery microchannel is 4.8, the micropore array is 4.9, and the white arrows indicate the direction of gas flow.
[0031] Figure 7 This is a cross-sectional view of the composite channel thermal protection structure;
[0032] In the diagram, the liquid inlet is 4.1; the primary liquid distribution chamber is 4.2; the liquid distribution orifice is 4.3; the secondary liquid distribution chamber is 4.12; the phase change heat transfer microchannel is 4.4; the collection chamber is 4.10; the outlet is 4.5; the gas inlet is 4.6; the primary gas distribution chamber is 4.11; the gas distribution orifice is 4.7; the secondary gas distribution chamber is 4.13; and the gas transport microchannel is 4.8. The black arrows indicate the direction of working fluid flow, and the white arrows indicate the direction of gas flow. Detailed Implementation
[0033] The present invention will be further described below with reference to specific embodiments and accompanying drawings.
[0034] like Figure 1 As shown, the active thermal protection system based on the composite channel structure includes an internal piping system and a composite channel thermal protection structure 4. The internal piping system is installed inside the aircraft, and the composite channel thermal protection structure 4 is installed on the surface of the aircraft as a thermal protection structure, with its outer surface being part of the aircraft wall. The liquid storage tank 1, flow pump 2, filter 3, composite channel thermal protection structure 4, and gas-liquid separator 5 are sequentially connected in a loop. Another path of the gas-liquid separator 5 is connected to the composite channel thermal protection structure 4 via a gas storage tank 6. The gas storage tank 6 and the composite channel thermal protection structure... A regulating valve 27 is provided between 4; a first shut-off valve 21 is provided between the liquid storage tank 1 and the flow pump 2; a back pressure valve 22 is provided between the composite channel thermal protection structure 4 and the gas-liquid separator 5; a first check valve 25 is provided between the gas-liquid separator and the gas storage tank 6; a second check valve 26 is provided between the liquid storage tank 1 and the gas-liquid separator 5; the first regulating valve 23, the heat-insulating pipeline 7, and the second shut-off valve 24 are connected in sequence, forming a bypass between the back pressure valve 22 and the gas storage tank 6; the gas storage tank 6 is provided with a heat-insulating pipeline 7 and a temperature-controlled heating belt, and the connecting arrows in the figure indicate the direction of medium transportation.
[0035] Before the aircraft takes off, the pressure-resistant liquid storage tank 1 is filled with a low-temperature liquid coolant. The coolant can be a liquid such as water with a phase change temperature lower than the target temperature for thermal protection cooling of the aircraft. At the same time, its physical properties need to meet the requirement that its gaseous micro-jet flow has heat-reducing flow characteristics.
[0036] When the aircraft flies at high speed, its walls are subjected to severe aerodynamic heating. When the monitored wall temperature reaches the threshold, the active thermal protection system's cooling cycle is activated. The cooling medium in the storage tank 1 is pumped by the flow pump 2 into the composite channel thermal protection structure. The cooling medium utilizes convective heat transfer and phase change endothermic processes within the microchannels to cool the solid structure. Under certain heat flux conditions, by changing the cooling medium flow rate, the convective heat transfer performance and vaporization rate can be altered, thereby changing the cooling performance to meet thermal protection requirements. Simultaneously, by adjusting the system pressure through the back pressure valve 22, the saturation temperature and vaporization rate of the medium can be changed, achieving a certain degree of temperature regulation of the structure. After the phase change, the two-phase flow medium enters the gas-liquid separator 5. The liquid medium returns to the storage tank 1 for circulation, while the gaseous medium enters the gas storage tank 6.
[0037] like Figure 2 As shown, the outer surface of the composite channel thermal protection structure 4 is provided with micro-jet flow holes. When phase change heat transfer is difficult to achieve cooling of the structure under severe aerodynamic heating, the gaseous working fluid in the gas storage tank enters the gas delivery microchannel 4.8 in the composite channel thermal protection structure 4, and enters the near-wall outer flow field in the form of micro-jet flow from the micro-hole array 4.9 to form a cooling gas film to reduce aerodynamic heat. Effective thermal protection of the aircraft under severe aerodynamic heating conditions is achieved by combining external cooling and internal cooling.
[0038] like Figure 3 As shown, the composite channel thermal protection structure 4 has a liquid inlet 4.1, an outlet 4.5, and a gas inlet 4.6 on its inner side. The liquid inlet 4.1 is connected to the filter 3, the outlet 4.5 is connected to the back pressure valve 22, and the gas inlet 4.6 is connected to the second regulating valve 27.
[0039] like Figure 4 As shown, the micropore array 4.9 region on the outer wall of the composite channel thermal protection structure 4 and the smooth, non-porous wall region are arranged in an alternating pattern, corresponding to the alternating pattern of the phase change heat transfer microchannel 4.4 and the gas transport microchannel 4.8 inside the structure.
[0040] like Figure 5 and Figure 6 As shown, the composite channel thermal protection structure 4 contains two parts: a phase change heat transfer channel array and a gas delivery channel array. The phase change heat transfer channel array is composed of a liquid inlet 4.1, a primary liquid distribution chamber 4.2, a liquid distribution hole 4.3, a secondary liquid distribution chamber 4.12, a phase change heat transfer microchannel 4.4, a collection chamber 4.10, and an outlet 4.5 connected in sequence. The gas delivery channel array is composed of a gas inlet 4.6, a primary gas distribution chamber 4.11, a gas distribution hole 4.7, a secondary gas distribution chamber 4.13, a gas delivery microchannel 4.8, and a micropore array 4.9 connected in sequence.
[0041] like Figure 7As shown, the phase change heat transfer microchannel 4.4 and the gas delivery microchannel 4.8 are arranged in a cross pattern to realize internal and external circulation paths in the same composite channel thermal protection structure 4, and to make the two functional areas reasonably distributed. This allows the system to combine the internal phase change cooling and external jet cooling functions in the active thermal protection process. By controlling the circulation of the system pipeline, the internal phase change cooling and external jet work separately to achieve effective thermal protection under different aerodynamic thermal conditions and improve the efficient utilization of the cooling medium.
[0042] The composite channel thermal protection structure 4 can be processed and shaped using additive manufacturing technology to achieve complex flow channel structure. At the same time, the specific structural features can be designed according to the specific application scenario. Its main function is to achieve efficient phase change cooling of internal circulation and efficient micro-jet cooling of external circulation through the reasonable layout of micro-flow channels, while the two functional flow channels are isolated from each other.
[0043] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. An active thermal protection system based on a composite channel structure, characterized in that: The system includes a liquid storage tank (1), a flow pump (2), a filter (3), a composite channel thermal protection structure (4), a gas-liquid separator (5), and a gas storage tank (6). The liquid storage tank (1), flow pump (2), filter (3), composite channel thermal protection structure (4), and gas-liquid separator (5) are sequentially connected in a loop. Another path of the gas-liquid separator (5) is connected to the composite channel thermal protection structure (4) via the gas storage tank (6). A second regulating valve (27) is provided between the gas storage tank (6) and the composite channel thermal protection structure (4). The liquid storage tank (1), flow pump (2), filter (3), composite channel thermal protection structure (4), and gas-liquid separator (5) are connected in a loop. 2) A first shut-off valve (21) is provided between the composite channel thermal protection structure (4) and the gas-liquid separator (5); a back pressure valve (22) is provided between the gas-liquid separator (5) and the gas storage tank (6); a first check valve (25) is provided between the liquid storage tank (1) and the gas-liquid separator (5); a second check valve (26) is provided between the liquid storage tank (1) and the gas-liquid separator (5); the first regulating valve (23), the heat-insulating pipeline (7) and the second shut-off valve (24) are connected in sequence, forming a bypass between the back pressure valve (22) and the gas storage tank (6); the gas storage tank (6) is provided with a heat-insulating pipeline (7) and a temperature-controlled heating belt (8).
2. The active thermal protection system based on a composite channel structure according to claim 1, characterized in that: The composite channel thermal protection structure (4) consists of two parts: a phase change heat transfer channel array and a gas delivery channel array. The phase change heat transfer channel array is composed of a liquid inlet (4.1), a primary liquid distribution chamber (4.2), a liquid distribution hole (4.3), a secondary liquid distribution chamber (4.12), a phase change heat transfer microchannel (4.4), a collection chamber (4.10), and an outlet (4.5) connected in sequence. The gas delivery channel array is composed of a gas inlet (4.6), a primary gas distribution chamber (4.11), a gas distribution hole (4.7), a secondary gas distribution chamber (4.13), a gas delivery microchannel (4.8), and a micropore array (4.9) connected in sequence.
3. The active thermal protection system based on a composite channel structure according to claim 1, characterized in that: The liquid inlet (4.1) of the composite channel thermal protection structure (4) is connected to the filter (3), the outlet (4.5) is connected to the back pressure valve (22), and the gas inlet (4.6) is connected to the second regulating valve (27).
4. The active thermal protection system based on a composite channel structure of claim 1, wherein: The heat-insulating pipe (7) and the temperature-controlled heating belt (8) are wrapped around the outer surface of the gas storage tank (6).
5. The active thermal protection system based on a composite channel structure according to claim 1, characterized in that: The composite channel thermal protection structure (4) is arranged on the wall surface of the high-speed aircraft that requires thermal protection, and its outer surface is part of the aircraft wall surface.
6. The active thermal protection system based on a composite channel structure according to claim 1, characterized in that: The working process is as follows: The system consists of two parts: a main loop and a gas branch. The liquid cooling medium in the storage tank (1) of the main loop is transported by the first shut-off valve (21) through the flow pump (2) and filtered by the filter (3) for fine impurities. Then, it enters the phase change heat exchange microchannel (4.4) in the composite channel heat protection structure (4) and cools the heat protection structure through phase change boiling heat exchange. After heat exchange, the gas-liquid two-phase mixed medium passes through the back pressure valve (22). Part of it directly enters the gas-liquid separator (5), and part of it enters the heat preservation pipeline (7) through the first regulating valve (23) and then returns to the main loop through the second shut-off valve (24) to enter the gas-liquid separator (5). The gas-liquid separator (5) separates the liquid cooling medium and flows back to the storage tank (1) through the second one-way valve (26). The gaseous working medium transported by the gas branch is obtained by separating the gas and liquid two-phase mixed working medium by the gas-liquid separator (5). The gaseous working medium enters the gas storage tank (6) through the first one-way valve (25). The second regulating valve (27) regulates the flow rate of the gaseous working medium entering the composite channel thermal protection structure (4). The gaseous working medium is transported in the gas transport microchannel (4.8) in the composite channel thermal protection structure (4) and injected into the near-wall flow field of the aircraft's external flow field in the form of micro-jet through the micro-hole array (4.9) on the channel wall, changing the velocity and temperature boundary layer distribution in the near-wall region and reducing the wall heat flux.
7. The active thermal protection system based on a composite channel structure according to claim 6, characterized in that: To maintain the gas pressure required for the micro-jet flow, the gas storage tank (6) is first insulated by the heat-insulating pipe (7) wrapped around the surface of the gas storage tank (6) to maintain a certain gas source pressure. When the temperature of the gas tank is difficult to reach the gas pressure requirement, the temperature is controlled by electric heating through the temperature-controlled heating belt (8) to regulate the jet gas source pressure.
8. The active thermal protection system based on a composite channel structure according to claim 2, characterized in that: The phase change heat transfer microchannel (4.4) and gas transport microchannel (4.8) in the composite channel heat protection structure (4) are not interconnected and are arranged in a cross pattern.