Active thermal protection system for high-speed aircraft and use method of active thermal protection system

Abstract

The invention discloses an active thermal protection system for a high-speed aircraft and a using method of the active thermal protection system. The system comprises a liquid storage tank, an active thermal protection plate, a gas high-pressure storage tank and a thrust engine. The liquid storage tank, the active thermal protection plate and the gas high-pressure storage tank are connected in sequence to form a loop; a first electromagnetic valve and a fourth electromagnetic valve are respectively arranged on a connecting pipeline between the liquid storage tank and the active thermal protection plate and a connecting pipeline between the gas high-pressure storage tank and the liquid storage tank; the gas high-pressure storage tank is further provided with two gas paths, one gas path is connected with the thrust engine through a third electromagnetic valve, and the other gas path is communicated with the outside through a second electromagnetic valve. The liquid storage tank is used for storing a liquid heat-absorbing working medium; and the active thermal protection plate is filled with a catalyst. The active thermal protection system is high in heat absorption capacity, high-temperature and high-pressure gas can be generated through aerodynamic heat to do work, waste heat utilization is achieved, the thickness of a thermal insulation layer of the aircraft is reduced, the effective load of the system is increased, and the maneuverability of the aircraft is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-speed aircraft, and more specifically, to an active thermal protection system for a high-speed aircraft and a method of using the system. Background Art

[0002] When an aircraft is flying at high speed, the temperature of its outer wall and nearby areas rises rapidly due to shock wave compression, viscous friction and other effects. In order to ensure that internal components work normally within the allowable temperature range and maintain their aerodynamic shape, effective structural thermal protection design must be carried out.

[0003] Thermal protection technology can be mainly divided into passive and active thermal protection technology. Passive thermal protection that uses thermal protection materials for insulation or ablative materials for phase change absorption of heat is the most widely used aerodynamic heat treatment measure and is used in many high-speed aircraft (such as the US X-30 and X-47). This type of thermal protection technology has a relatively simple structure, but the preparation process is complex and the cost is high. When the ablative thermal protection system is flying at high speed, the material will gradually be ablated as the temperature rises, which can easily change the overall aerodynamic shape and cause accidents. At the same time, due to the weak heat absorption capacity of the passive thermal protection system, the thickness and weight of the materials required in long-flight applications are large, which seriously compresses the payload of the aircraft. Active thermal protection technology is mainly divided into two categories, namely sweat cooling and convection cooling. The commonly used cooling medium for sweat cooling is water. It draws on the way organisms sweat to dissipate heat, using the latent heat of vaporization of water to absorb heat and form a thermal insulation barrier, but the system reliability is poor. Convection cooling is often used in aerospace vehicles or aviation vehicles. Generally, circulating liquid hydrocarbon fuel is used as a coolant, and the heat from the surface of the structure is removed by the physical heat capacity of the fuel. Due to the limitation of fuel coking, this heat absorption mode is only suitable for supersonic flight at speeds below Mach 5 and cannot meet the thermal protection requirements of higher speeds.

[0004] In recent years, with the further improvement of high-speed aircraft performance, especially the development of long-endurance global strike aircraft, its aerodynamic thermal environment has become more complex and harsh. Therefore, it is of great significance to develop an efficient and reliable aerodynamic thermal protection method for high-speed aircraft. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and to provide an active thermal protection system for high-speed aircraft and a method of using the same. The active thermal protection system not only has a strong heat absorption capacity, but can also use aerodynamic heat to generate high-temperature and high-pressure gas to do work, thereby realizing waste heat utilization, thereby reducing the thickness of the aircraft's thermal insulation layer, increasing the system's payload, and effectively improving the aircraft's maneuverability.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] An active thermal protection system for a high-speed aircraft, the system comprising: a liquid storage tank 1, an active thermal protection plate 3, a gas high-pressure storage tank 4 and a thrust engine 7; the liquid storage tank 1, the active thermal protection plate 3 and the gas high-pressure storage tank 4 are sequentially connected to form a loop; a first solenoid valve 2 and a fourth solenoid valve 8 are respectively provided on the connecting pipeline between the liquid storage tank 1 and the active thermal protection plate 3, and on the connecting pipeline between the gas high-pressure storage tank 4 and the liquid storage tank 1; the gas high-pressure storage tank 4 is also provided with two gas paths, one of which is connected to the thrust engine 7 through a third solenoid valve 6, and the other is connected to the outside through a second solenoid valve 5; the liquid storage tank 1 is used to store liquid heat-absorbing working fluid; the active thermal protection plate 3 is filled with a catalyst.

[0008] Optionally, when the liquid endothermic working fluid includes one of water, aqueous ammonia and a mixed solution of alcohol and water, the catalyst is a carbon-based material.

[0009] Optionally, when the liquid endothermic working fluid is ammonia water or an alcohol-water mixed solution, the catalyst is a double-bed catalytic system consisting of a front-bed catalyst and a rear-bed catalyst; the front-bed catalyst is a supported catalyst; and the rear-bed catalyst is a carbon-based material.

[0010] Optionally, the filling volume of the front bed catalyst accounts for 5% to 25% of the total volume of the active heat protection plate 3 ; the filling volume of the rear bed catalyst accounts for 75% to 95% of the total volume of the active heat protection plate 3 .

[0011] Optionally, the mass concentration of the ammonia water is 1% to 25%.

[0012] Optionally, the mass concentration of the alcohol component in the alcohol-water mixed solution is 1% to 75%; the alcohol-water mixed solution includes an aqueous solution containing at least one of methanol, ethanol, ethylene glycol, propanol, and isopropanol.

[0013] Optionally, the carbon-based material is at least one of metal-modified wood activated carbon, coconut shell charcoal, almond charcoal or two-dimensional carbon material.

[0014] Optionally, the metal includes at least one of K, Mg, Ca, La, Fe, Ni, Co, Cu and Ru.

[0015] Optionally, in the carbon-based material, the mass content of the modified metal accounts for 0wt% to 15wt% of the carbon-based material.

[0016] Optionally, the supported catalyst includes silicon-modified alumina and an active component supported on the silicon-modified alumina.

[0017] Optionally, the active component includes at least one of Ru, Cu, Ni, and Pt.

[0018] Optionally, the mass fraction of the active component in the supported catalyst is 10 wt% to 30 wt%.

[0019] The present invention also discloses a method for using the active thermal protection system for a high-speed aircraft, comprising the following steps:

[0020] When the outer wall temperature of the active heat protection plate 3 reaches 400°C to 900°C, the liquid heat absorbing medium stored in the liquid storage tank 1 is transported to the active heat protection plate 3 through a pipeline. The liquid heat absorbing medium first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a chemical reaction under the action of a catalyst to produce high-pressure gas small molecules to achieve aerodynamic heat absorption. The high-pressure gas small molecules are transported to the gas high-pressure storage tank 4 through a pipeline for storage;

[0021] When the pressure of the liquid storage tank 1 is less than 0.5 MPa, the first solenoid valve 2, the second solenoid valve 5 and the third solenoid valve 6 are closed, and the fourth solenoid valve 8 is opened to condense part of the unreacted endothermic working fluid and enter the liquid storage tank 1 through the solenoid valve 8, so as to realize the recycling of the endothermic working fluid;

[0022] When the high-speed aircraft switches state, the fourth solenoid valve 8 and the second solenoid valve 5 are closed, the third solenoid valve 6 is opened and the high-pressure fuel gas small molecules are introduced, and discharged through the thrust engine 7, thereby generating thrust by doing work;

[0023] When the power of the high-speed aircraft meets the flight state, the fourth solenoid valve 8 and the third solenoid valve 6 are closed, and the second solenoid valve 5 is opened. The small molecules of high-pressure fuel gas are discharged from the pipeline until the pressure of the gas high-pressure storage tank 4 is 0.5MPa~3MPa, and then the second solenoid valve 5 is closed.

[0024] Optionally, when the liquid endothermic medium is water, ammonia water or an alcohol-water mixed solution, the liquid endothermic medium transported into the active thermal protection plate 3 at a feed rate of 0.5 g / s to 50 g / s first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a water-carbon vaporization reaction and an ammonia decomposition reaction or an alcohol-water reforming reaction under the action of carbon-based materials to produce high-pressure fuel gas small molecules.

[0025] Optionally, when the liquid endothermic working fluid is ammonia water or an alcohol-water mixed solution, the liquid endothermic working fluid transported into the active thermal protection plate 3 at a feed rate of 0.5g / s to 50g / s first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a water-carbon vaporization reaction and an ammonia decomposition reaction or an alcohol-water reforming reaction under the action of the dual-bed catalytic system to produce high-pressure fuel gas small molecules; wherein, the front bed catalyst in the dual-bed catalytic system is a loaded catalyst, and the rear bed catalyst is a carbon-based material.

[0026] The present invention also discloses a high-speed aircraft, comprising the above-mentioned active thermal protection system for the high-speed aircraft.

[0027] Implementing the embodiments of the present invention will have the following beneficial effects:

[0028] 1. Compared with the traditional passive heat insulation method, the active thermal protection system for high-speed aircraft provided by the present invention belongs to the active thermal protection technology, which has the advantages of strong cooling capacity, being able to withstand long-term heating of high-density heat flow, and realizing closed-loop temperature control.

[0029] 2. Compared with the active heat insulation method of water sweating, the active thermal protection system for high-speed aircraft provided by the present invention can not only take advantage of the physical heat absorption of the liquid heat absorbing medium, but also enhance the heat absorption through chemical reactions. The theoretical maximum heat absorption capacity of the system is more than doubled (>6MJ / kg) compared with the heat absorption of water sweating (~3MJ / kg). When further coupled with ammonia decomposition, alcohol decomposition or alcohol-water reforming reactions, the heat absorption performance of the system can be further enhanced.

[0030] 3. Compared with the heat absorption of hydrocarbon fuels (heat sink), the active thermal protection system for high-speed aircraft provided by the present invention has a higher theoretical heat sink and can be applied to application scenarios with flight speeds higher than Mach 5.

[0031] 4. The active thermal protection system for high-speed aircraft provided by the present invention is reasonably and compactly arranged, easy to control and maintain.

[0032] 5. The active thermal protection system provided by the present invention can be used in high-speed aircraft, which can not only meet the temperature control requirements of high-speed aircraft for long-distance and long-term flight; at the same time, the system does not need to use thicker or heavier materials, which is beneficial to aircraft weight reduction and avoids compression of the aircraft's payload.

[0033] 6. In the active thermal protection system for high-speed aircraft provided by the present invention, one path of the gas high-pressure storage tank is connected to the thrust engine, thereby generating thrust work, thereby achieving adjustment of the attitude and speed of the high-speed aircraft and improving its maneuverability; the other path of the gas high-pressure storage tank is connected to the outside through the third solenoid valve, which can avoid the occurrence of safety accidents caused by increased pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of an active thermal protection system for a high-speed aircraft according to an embodiment of the present invention.

[0035] Figure 2 This is a diagram of the active thermal protection mechanism based on liquid water heat absorbing medium according to an embodiment of the present invention.

[0036] Figure 3 This is a diagram of the active thermal protection mechanism based on liquid alcohol-water heat absorbing medium according to an embodiment of the present invention.

[0037] Figure 4 This is a diagram of the active thermal protection mechanism based on liquid ammonia water endothermic working fluid according to an embodiment of the present invention.

[0038] Among them, 1. liquid storage tank, 2. first solenoid valve, 3. active thermal protection plate, 4. gas high-pressure storage tank, 5. second solenoid valve, 6. third solenoid valve, 7. thrust engine, 8. fourth solenoid valve. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0040] The present invention discloses an active thermal protection system for a high-speed aircraft, the system comprising: a liquid storage tank 1, an active thermal protection plate 3, a gas high-pressure storage tank 4 and a thrust engine 7; the liquid storage tank 1, the active thermal protection plate 3 and the gas high-pressure storage tank 4 are sequentially connected to form a loop; a first solenoid valve 2 and a fourth solenoid valve 8 are respectively arranged on a connecting pipeline between the liquid storage tank 1 and the active thermal protection plate 3, and a connecting pipeline between the gas high-pressure storage tank 4 and the liquid storage tank 1; the gas high-pressure storage tank 4 is also provided with two gas paths, one of which is connected to the thrust engine 7 through a third solenoid valve 6, and the other is connected to the outside through a second solenoid valve 5; the liquid storage tank 1 is used to store a liquid endothermic working medium; and a catalyst is filled inside the active thermal protection plate 3.

[0041] In a specific embodiment, when the liquid endothermic medium includes one of water, aqueous ammonia and a mixed solution of alcohol and water, the catalyst is a carbon-based material.

[0042] In a specific embodiment, when the liquid endothermic working fluid is ammonia water or an alcohol-water mixed solution, the catalyst is a double-bed catalyst system consisting of a front-bed catalyst and a rear-bed catalyst; the front-bed catalyst is a supported catalyst; and the rear-bed catalyst is a carbon-based material.

[0043] In a specific embodiment, the filling volume of the front bed catalyst accounts for 5% to 25% of the total volume of the active heat protection plate 3 ; the filling volume of the rear bed catalyst accounts for 75% to 95% of the total volume of the active heat protection plate 3 .

[0044] In a specific embodiment, the mass concentration of the ammonia water is 1% to 25%.

[0045] In a specific embodiment, the mass concentration of the alcohol component in the alcohol-water mixed solution is 1% to 75%; the alcohol-water mixed solution includes an aqueous solution containing at least one of methanol, ethanol, ethylene glycol, propanol, and isopropanol.

[0046] In a specific embodiment, the carbon-based material is at least one of metal-modified wood activated carbon, coconut shell charcoal, almond charcoal or a two-dimensional carbon material.

[0047] In a specific embodiment, the metal includes at least one of K, Mg, Ca, La, Fe, Ni, Co, Cu and Ru.

[0048] In a specific embodiment, in the carbon-based material, the mass content of the modified metal accounts for 0wt% to 15wt% of the carbon-based material.

[0049] In a specific embodiment, the supported catalyst includes silicon-modified alumina and an active component supported on the silicon-modified alumina.

[0050] In a specific embodiment, the active component includes at least one of Ru, Cu, Ni, and Pt.

[0051] In a specific embodiment, the mass fraction of the active component in the supported catalyst is 10 wt% to 30 wt%.

[0052] The present invention also discloses a method for using the active thermal protection system for a high-speed aircraft, comprising the following steps:

[0053] When the outer wall temperature of the active heat protection plate 3 reaches 400°C to 900°C, the liquid heat absorbing medium stored in the liquid storage tank 1 is transported to the active heat protection plate 3 through a pipeline, and the liquid heat absorbing medium first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a chemical reaction under the action of a catalyst to produce high-pressure gas small molecules to achieve aerodynamic heat absorption, and the high-pressure gas small molecules are transported to the gas high-pressure storage tank 4 through a pipeline for storage;

[0054] When the pressure of the liquid storage tank 1 is less than 0.5 MPa, the first solenoid valve 2, the second solenoid valve 5 and the third solenoid valve 6 are closed, and the fourth solenoid valve 8 is opened to condense part of the unreacted endothermic working fluid and enter the liquid storage tank 1 through the solenoid valve 8, so as to realize the recycling of the endothermic working fluid;

[0055] When the high-speed aircraft switches state, the fourth solenoid valve 8 and the second solenoid valve 5 are closed, the third solenoid valve 6 is opened and the high-pressure fuel gas small molecules are introduced, which are discharged through the thrust engine 7, and then work is performed to generate thrust;

[0056] When the power of the high-speed aircraft meets the flight state, the fourth solenoid valve 8 and the third solenoid valve 6 are closed, the second solenoid valve 5 is opened, and the small molecules of high-pressure fuel gas are discharged from the pipeline until the pressure of the gas high-pressure storage tank 4 is 0.5MPa~3MPa, and then the second solenoid valve 5 is closed.

[0057] In a specific embodiment, when the liquid endothermic working fluid is water, ammonia water or an alcohol-water mixed solution, the liquid endothermic working fluid transported into the active thermal protection plate 3 at a feed rate of 0.5 g / s to 50 g / s first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a water-carbon vaporization reaction and an ammonia decomposition reaction or an alcohol-water reforming reaction under the action of the carbon-based material to produce high-pressure gas small molecules.

[0058] In a specific embodiment, when the liquid endothermic working fluid is ammonia water or an alcohol-water mixed solution, the liquid endothermic working fluid transported into the active thermal protection plate 3 at a feed rate of 0.5g / s to 50g / s first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a water-carbon vaporization reaction and an ammonia decomposition reaction or an alcohol-water reforming reaction under the action of the dual-bed catalytic system to produce high-pressure fuel gas small molecules; wherein, the front bed catalyst in the dual-bed catalytic system is a loaded catalyst, and the rear bed catalyst is a carbon-based material.

[0059] The present invention also discloses a high-speed aircraft, comprising the active thermal protection system for the high-speed aircraft according to any embodiment of the present invention.

[0060] The following are specific embodiments

[0061] Example 1

[0062] Figure 1 The active thermal protection system for high-speed aircraft according to an embodiment of the present invention is a schematic diagram, which includes a liquid storage tank 1, a first solenoid valve 2, an active thermal protection plate 3, a gas high-pressure storage tank 4, a second solenoid valve 5, a third solenoid valve 6, a thrust engine 7 and a fourth solenoid valve 8; wherein, the outlet of the liquid storage tank 1 is connected to the inlet of the active thermal protection plate 3, the outlet of the active thermal protection plate 3 is connected to the inlet of the gas high-pressure storage tank 4, and one path of the gas high-pressure storage tank 4 is connected to the liquid storage tank 1 to form a loop; the connecting pipeline between the liquid storage tank 1 and the active thermal protection plate 3 and the connecting pipeline between the gas high-pressure storage tank 4 and the liquid storage tank 1 are respectively provided with a first solenoid valve 2 and a fourth solenoid valve 8; the gas high-pressure storage tank 4 is also provided with two gas paths, one of which is connected to the thrust engine 7 through the third solenoid valve 6, and the other is connected to the outside through the second solenoid valve 5; the liquid storage tank 1 is used to store liquid heat-absorbing working fluid; the interior of the active thermal protection plate 3 is filled with a catalyst.

[0063] When the liquid endothermic medium is water, the catalyst is a carbon-based material. The specific mechanism is as follows: Figure 2As shown, the method for using the active thermal protection system of this embodiment includes the following steps: when the outer wall temperature of the active thermal protection plate 3 reaches 400°C to 900°C, the first solenoid valve 2 is opened, and the liquid endothermic working medium water stored in the liquid storage tank 1 is transported to the active thermal protection plate 3 through a pipeline at a feed rate of 0.5g / s to 50g / s. The liquid endothermic working medium water first undergoes a vaporization reaction (reaction 1) under the action of aerodynamic heat to absorb aerodynamic heat, and then undergoes a strong endothermic chemical reaction (reaction 2) under the action of carbon-based materials and produces high-pressure gas small molecules to achieve aerodynamic heat absorption. The high-pressure gas small molecules are transported to the gas high-pressure storage tank 4 through a pipeline for storage.

[0064] When the liquid endothermic medium is a mixed solution of alcohol and water, the catalyst is a carbon-based material. The specific mechanism is as follows: Figure 3 As shown, the method for using the active thermal protection system of the present embodiment comprises the following steps: when the outer wall temperature of the active thermal protection plate 3 reaches 400°C to 900°C, the first solenoid valve 2 is opened, and the liquid endothermic alcohol-water mixed solution stored in the liquid storage tank 1 is transported to the active thermal protection plate 3 through a pipeline at a feed rate of 0.5g / s to 50g / s, the alcohol-water mixed solution first undergoes a vaporization reaction (reaction 3) to absorb aerodynamic heat under the action of aerodynamic heat, and then undergoes a strongly endothermic alcohol-water reforming reaction (reaction 5) and a water-carbon vaporization reaction (reaction 4) under the action of carbon-based materials and produces high-pressure gas small molecules to achieve aerodynamic heat absorption, and the high-pressure gas small molecules are transported to the gas high-pressure storage tank 4 through a pipeline for storage.

[0065] When the liquid endothermic medium is ammonia, the catalyst is a carbon-based material. The specific mechanism is as follows: Figure 4 As shown, the method for using the active thermal protection system of this embodiment includes the following steps: when the outer wall temperature of the active thermal protection plate 3 reaches 400°C to 900°C, the first solenoid valve 2 is opened, and the liquid endothermic working fluid ammonia water stored in the liquid storage tank 1 is transported to the active thermal protection plate 3 through a pipeline at a feed rate of 0.5g / s to 50g / s. The ammonia water first undergoes a vaporization reaction under the action of aerodynamic heat to absorb aerodynamic heat (reaction 6), and then undergoes a strongly endothermic ammonia decomposition reaction (reaction 8) and a water-carbon vaporization reaction (reaction 7) under the action of carbon-based materials, and produces high-pressure gas small molecules to achieve aerodynamic heat absorption. The high-pressure gas small molecules are transported to the gas high-pressure storage tank 4 through a pipeline for storage.

[0066] When the liquid endothermic working fluid is ammonia water or an alcohol-water mixed solution, the catalyst is a dual-bed catalytic system, the front-bed catalyst is a supported catalyst, and the rear-bed catalyst is a carbon-based material. The filling volume of the front-bed catalyst accounts for 5% to 25% of the total volume of the active heat protection plate (3), and the filling volume of the rear-bed catalyst accounts for 75% to 95% of the total volume of the active heat protection plate 3. The front-bed catalyst is further used to enhance the reaction rates of ammonia decomposition and alcohol-water reforming.

[0067] Among them, the mass concentration of ammonia water is 1% to 25%; the mass concentration of the alcohol component in the alcohol-water mixed solution is 1% to 75%; the alcohol-water mixed solution includes an aqueous solution containing at least one of methanol, ethanol, ethylene glycol, propanol, and isopropanol; the carbon-based material is at least one of metal-modified wood activated carbon, coconut shell charcoal, almond charcoal or two-dimensional carbon material; the metal includes at least one of K, Mg, Ca, La, Fe, Ni, Co, Cu and Ru; in the carbon-based material, the mass content of the modified metal accounts for 0wt% to 15wt% of the carbon-based material; the supported catalyst includes silicon-modified alumina and an active component supported on the silicon-modified alumina; the active component includes at least one of Ru, Cu, Ni, and Pt; the mass fraction of the active component in the supported catalyst is 10wt% to 30wt%.

[0068] When the liquid endothermic working fluid is water, the reaction mechanism is as follows:

[0069] H2O(l)→H2O(g) (Reaction 1)

[0070] C(s)+H2O(g)→CO(g)+H2(g) (Reaction 2)

[0071] When the liquid endothermic working fluid is an alcohol-water mixed solution, the reaction mechanism is as follows:

[0072] H2O(l)+C n H 2n+2 O m (l)→H2O(g)+C n H 2n+2 O m (g) (Reaction 3)

[0073] C(s)+H2O(g)→CO(g)+H2(g) (Reaction 4)

[0074] C n H 2n+2 O m (g)+(nm)H2O→(n+1)H2(g)+nCO(g)(Reaction 5)

[0075] When the liquid endothermic working fluid is ammonia water, the reaction mechanism is as follows:

[0076] H2O(l)+NH3(l)→H2O(g)+NH3(g) (Reaction 6)

[0077] C(s)+H2O(g)→CO(g)+H2(g) (Reaction 7)

[0078] 2NH3(g)→N2(g)+3H2(g)(Reaction 8)

[0079] Furthermore, when the pressure of the liquid storage tank 1 is less than 0.5 MPa, the first solenoid valve 2, the second solenoid valve 5 and the third solenoid valve 6 are closed, and the fourth solenoid valve 8 is opened to condense part of the unreacted endothermic working fluid and enter the liquid storage tank 1 through the solenoid valve 8, thereby realizing the recycling of the endothermic working fluid.

[0080] Furthermore, when the high-speed aircraft switches states, the fourth solenoid valve 8 and the second solenoid valve 5 are closed, the third solenoid valve 6 is opened and high-pressure fuel gas small molecules are introduced, discharged through the thrust engine 7, and then work is performed to generate thrust.

[0081] Furthermore, when the power of the high-speed aircraft meets the flight state, the fourth solenoid valve 8 and the third solenoid valve 6 are closed, the second solenoid valve 5 is opened, and the small molecules of high-pressure fuel gas are discharged from the pipeline until the pressure of the gas high-pressure storage tank 4 is 0.5MPa~3MPa, and then the second solenoid valve 5 is closed.

[0082] The working principle is: using the sensible heat of the liquid heat-absorbing working fluid and the latent heat of vaporization phase change to absorb part of the aerodynamic heat. More importantly, the water vapor in the heat-absorbing working fluid can react with the carbon-based filling material to produce a chemical reaction with strong heat-absorbing characteristics, thereby significantly improving the heat absorption capacity of the system. When ammonia water or a mixed solution of alcohol and water is added to the liquid heat-absorbing working fluid, the heat absorption capacity of the system can be further improved through ammonia decomposition, organic alcohol decomposition or organic alcohol reforming reaction. In addition, the high-pressure small molecule gases such as hydrogen and carbon monoxide produced by the chemical reaction can be ejected through the thrust engine to do work, thereby realizing the adjustment of the attitude and speed of the high-speed aircraft and improving its maneuverability.

[0083] Example 2

[0084] The liquid endothermic working fluid of this embodiment is water, the catalyst is a carbon-based material, the outer wall temperature of the active heat protection plate is 600°C, the reaction pressure of the gas high-pressure storage tank is 1.5MPa, the carbon-based materials are coconut shell charcoal modified with K, Mg, Ca, La, Fe, Ni, Co, Cu, Ru, FeCu, and NiCu, the total mass fraction of the metal in the carbon-based material is 5%, and the water feed rate is 0.5g / s.

[0085] Table 1 Maximum gas production rate of different metal modified carbon carriers

[0086]

[0087] According to the results in Table 1, the modified metal components on the carbon-based carrier will significantly affect the chemical reaction rate. When there is only one modified metal, the reaction activity of the precious metal Ru is the greatest, resulting in the highest gas production rate. For non-precious metal modified metals, Fe and Cu modification effects are the best, especially when the two are mixed, the gas production rate is slightly improved to 82% of the Ru modification performance. After modification with different metals, the gas production components are basically the same, and the total volume content of H2 and CO (excluding water) reaches 97%, indicating that the water gas reaction mainly occurs, and the theoretical heat absorption capacity of the system can reach more than 6.2 kJ / g.

[0088] Example 3

[0089] The only difference between this embodiment and embodiment 2 is that the carbon-based materials are Fe-modified wood activated carbon, almond charcoal, and graphene.

[0090] Table 2 Comparison of maximum gas production rates of different carbon carriers

[0091]

[0092] According to the results in Table 2, different carbon-based carriers will significantly affect the chemical reaction rate. Compared with two-dimensional carbon materials, wood activated carbon, almond charcoal and coconut shell carbon have better performance in the reaction.

[0093] Example 4

[0094] The only difference between this embodiment and embodiment 2 is that the outer wall temperatures of the active thermal protection plate are 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, and 1000°C, respectively, and the carbon-based material is Fe-modified coconut shell charcoal.

[0095] Table 3 Comparison of maximum gas production rates at different reaction temperatures

[0096]

[0097] According to the results in Table 3, different reaction temperatures will significantly affect the chemical reaction rate. When the temperature is below 400 °C, the gas production rate is extremely low, and as the reaction temperature increases, the system gas production rate increases significantly. However, when the temperature is above 900 °C, the system gas production rate does not change significantly.

[0098] Example 5

[0099] The only difference between this embodiment and embodiment 2 is that the reaction pressures of the gas high-pressure storage tank are 0.5 MPa, 1.0 MPa, 2.0 MPa, and 3.0 MPa, respectively, and the carbon-based material is Fe-modified coconut shell charcoal.

[0100] Table 4 Comparison of maximum gas production rates at different pressures

[0101]

[0102] According to the results in Table 4, different reaction pressures will significantly affect the chemical reaction rate. As the reaction pressure increases, the system gas production rate increases significantly, indicating that the increase in pressure is conducive to promoting the chemical reaction.

[0103] Example 6

[0104] The only difference between this embodiment and embodiment 2 is that the carbon-based material is coconut shell charcoal modified with Fe, and the total mass fraction of the modified metal Fe in the carbon-based material is 1%, 10%, and 15%, respectively.

[0105] Table 5 Comparison of maximum gas production rate at different metal loadings

[0106]

[0107] According to the results in Table 5, as the metal loading increases, the gas production rate of the system gradually increases, especially when the metal loading is 10%, which can effectively promote the chemical reaction, and as the metal loading is further increased to 15%, the gas production rate remains basically unchanged.

[0108] Example 7

[0109] The present embodiment is different from the embodiment 2 in that the liquid endothermic medium is an alcohol-water mixed solution, the mass concentration of the alcohol component in the alcohol-water mixed solution is 10%, and the carbon-based material is Fe-Cu modified coconut shell charcoal.

[0110] Table 6 Comparison of maximum gas production rates of different alcohol-water working fluids

[0111]

[0112] According to the results in Table 6, compared with liquid endothermic water, when the liquid endothermic working fluid is a mixed solution of alcohol and water, the gas production rate of the system can be effectively improved. Among them, the aqueous solution containing methanol has the best effect, and the gas production rate can reach 35.2L / min. According to the product composition and temperature, the total heat absorption of the system (including phase change endothermic, sensible heat and chemical reaction endothermic) calculated by ASPEN software can reach 5.9kJ / g.

[0113] Example 8

[0114] The only difference between this embodiment and embodiment 2 is that the liquid endothermic working fluid is ammonia water, wherein the mass concentration of ammonia water is 5%, 10%, and 25% respectively, and the carbon-based material is coconut shell charcoal modified with Fe.

[0115] Table 7 Comparison of maximum gas production rates of different concentrations of ammonia working fluid

[0116]

[0117] According to the results in Table 7, compared with liquid endothermic water, when the liquid endothermic working fluid is ammonia water, the gas production rate can be effectively increased, and as the ammonia concentration increases, the gas production rate also increases significantly.

[0118] Example 9

[0119] The liquid endothermic working fluid of this embodiment is ammonia water, and the catalyst is a dual-bed catalytic system, which is specifically as follows: the liquid endothermic working fluid is ammonia water with a mass concentration of 25%, and a dual-bed catalytic system is constructed in the active heat protection plate, that is, the front bed is a loaded catalyst (the filling volume accounts for 1 / 4 of the total volume of the heat protection plate), and the rear bed is a carbon-based material (the filling volume accounts for 3 / 4 of the total volume of the heat protection plate), wherein the catalyst carrier of the front bed is silicon-modified alumina, the active metals are Ru and Pt (Ru / Pt molar ratio is 1), the active metals account for 20% of the total mass of the loaded catalyst, and the carbon-based material of the rear bed is Fe-modified coconut shell carbon, and the other conditions are consistent with Example 2.

[0120] The results showed that when a dual-bed catalyst was used, the gas production rate increased to 46.1 L / min, which was 34.4% higher than the gas production rate of a single carbon-based filler material (34.3 L / min), and the system heat absorption increased from 5.6 kJ / g to 6.0 kJ / g. This shows that the dual-bed system can effectively improve the system's work and heat absorption performance.

[0121] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An active thermal protection system for high-speed aircraft, characterized in that: The system comprises: a liquid storage tank (1), an active heat protection plate (3), a gas high-pressure storage tank (4) and a thrust engine (7); The liquid storage tank (1), the active heat protection plate (3) and the gas high-pressure storage tank (4) are sequentially connected to form a loop; A first solenoid valve (2) and a fourth solenoid valve (8) are respectively provided on the connecting pipeline between the liquid storage tank (1) and the active heat protection plate (3), and on the connecting pipeline between the gas high-pressure storage tank (4) and the liquid storage tank (1); The gas high-pressure storage tank (4) is also provided with two gas paths, one of which is connected to the thrust engine (7) via a third solenoid valve (6), and the other is connected to the outside via a second solenoid valve (5); The liquid storage tank (1) is used to store liquid heat-absorbing working fluid; The interior of the active heat protection plate (3) is filled with a catalyst.

2. The active thermal protection system for high-speed aircraft according to claim 1, characterized in that: When the liquid heat-absorbing working medium includes one of water, ammonia water and alcohol-water mixed solution, the catalyst is a carbon-based material.

3. The active thermal protection system for high-speed aircraft according to claim 1, characterized in that: When the liquid endothermic working fluid is ammonia water or an alcohol-water mixed solution, the catalyst is a double-bed catalyst system consisting of a front-bed catalyst and a rear-bed catalyst; The front bed catalyst is a supported catalyst; The rear bed catalyst is a carbon-based material; The filling volume of the front bed catalyst accounts for 5% to 25% of the total volume of the active heat protection plate (3); The filling volume of the rear bed catalyst accounts for 75% to 95% of the total volume of the active heat protection plate (3).

4. The active thermal protection system for high-speed aircraft according to claim 2 or 3, characterized in that: The mass concentration of the ammonia water is 1% to 25%; The mass concentration of the alcohol component in the alcohol-water mixed solution is 1% to 75%; The alcohol-water mixed solution includes an aqueous solution containing at least one of methanol, ethanol, ethylene glycol, propanol, and isopropanol.

5. The active thermal protection system for high-speed aircraft according to claim 2 or 3, characterized in that: The carbon-based material is at least one of metal-modified wood activated carbon, coconut shell charcoal, almond charcoal or two-dimensional carbon material; The metal includes at least one of K, Mg, Ca, La, Fe, Ni, Co, Cu and Ru; In the carbon-based material, the mass content of the modified metal accounts for 0wt% to 15wt% of the carbon-based material.

6. The active thermal protection system for high-speed aircraft according to claim 3, characterized in that: The supported catalyst comprises silicon-modified alumina and an active component supported on the silicon-modified alumina; The active component includes at least one of Ru, Cu, Ni and Pt; The mass fraction of the active component in the supported catalyst is 10 wt% to 30 wt%.

7. A method for using the active thermal protection system for a high-speed aircraft as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: When the outer wall temperature of the active heat protection plate (3) is 400° C. to 900° C., the liquid heat absorbing medium stored in the liquid storage tank (1) is transported to the active heat protection plate (3) through a pipeline, the liquid heat absorbing medium first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a chemical reaction under the action of a catalyst to produce high-pressure gas small molecules to achieve aerodynamic heat absorption, and the high-pressure gas small molecules are transported to the gas high-pressure storage tank (4) through a pipeline for storage; When the pressure of the liquid storage tank (1) is less than 0.5 MPa, the first solenoid valve (2), the second solenoid valve (5) and the third solenoid valve (6) are closed, and the fourth solenoid valve (8) is opened, so that part of the unreacted endothermic working fluid is condensed and enters the liquid storage tank (1) through the solenoid valve (8), thereby realizing the recycling of the endothermic working fluid; When the high-speed aircraft switches state, the fourth solenoid valve (8) and the second solenoid valve (5) are closed, the third solenoid valve (6) is opened and the high-pressure fuel gas small molecules are introduced, discharged through the thrust engine (7), and then work is performed to generate thrust; When the power of the high-speed aircraft meets the flight state, the fourth solenoid valve (8) and the third solenoid valve (6) are closed, the second solenoid valve (5) is opened, and the small molecules of the high-pressure fuel gas are discharged from the pipeline until the pressure of the gas high-pressure storage tank (4) reaches 0.5MPa to 3MPa, and then the second solenoid valve (5) is closed.

8. The active thermal protection system for high-speed aircraft according to claim 7, characterized in that: When the liquid endothermic medium is water, ammonia water or an alcohol-water mixed solution, the liquid endothermic medium transported into the active heat protection plate (3) at a feed rate of 0.5 g / s to 50 g / s first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a water-carbon vaporization reaction and an ammonia decomposition reaction or an alcohol-water reforming reaction under the action of the carbon-based material to produce high-pressure fuel gas small molecules.

9. The active thermal protection system for high-speed aircraft according to claim 7, characterized in that: When the liquid endothermic working fluid is ammonia water or an alcohol-water mixed solution, the liquid endothermic working fluid transported into the active heat protection plate (3) at a feed rate of 0.5 g / s to 50 g / s first undergoes a vaporization reaction under the action of aerodynamic heat, and then undergoes a water-carbon vaporization reaction and an ammonia decomposition reaction or an alcohol-water reforming reaction under the action of the dual-bed catalytic system to produce high-pressure fuel gas small molecules; wherein the front bed catalyst in the dual-bed catalytic system is a loaded catalyst, and the rear bed catalyst is a carbon-based material.

10. A high-speed aircraft, characterized in that: An active thermal protection system for a high-speed aircraft comprising any one of claims 1-6.

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