Ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system

Abstract

The invention provides an ammonia / kerosene dual-fuel precooling engine and a fuel cell power generation system, and belongs to the technical field of aviation systems. The problems of poor variable working condition performance of an engine, difficulty in matching of a gas compressor and a turbine, low working efficiency, fuel waste and the like due to the fact that working of the gas compressor is limited by overhigh total temperature of flying incoming flow air under the high Mach number of an aircraft are solved. According to the invention, the electric energy generated by the solid oxide fuel cell system is supplied to the aircraft load and the motor, and the motor drives the secondary gas compressor to do work in a manner of coaxial installation with the secondary gas compressor, so that the previous single-pole compression is changed into multi-stage compression. A dual-fuel pre-cooling propulsion method is adopted, liquid ammonia and aviation kerosene are selected as dual fuels of the system, the heat sink requirement for incoming flow air pre-cooling can be met, the fuel heat value requirement needed when the aircraft flies at the high Mach number can also be met, and therefore stable and safe flight of the aircraft at the hypersonic speed becomes possible.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation systems, and in particular relates to an ammonia / kerosene dual-fuel precooling engine and a fuel cell power generation system. Background Art

[0002] One of the keys to optimizing near-space hypersonic vehicles and two-stage orbital space transportation systems is engine technology, among which air precooling combined engines have always been one of the important research directions. By setting a precooler at the compressor inlet and using fuel cooling to reduce the inlet air temperature, the power consumption of the compressor can be significantly reduced, thereby improving the engine cycle efficiency.

[0003] Ammonia is a hydrogen-rich gas. Compared with hydrogen, it has a high volume energy density, is easy to liquefy, store and transport, is safer and more economical than other common fuels, and has little environmental harm. In addition, there is sufficient supply of ammonia in the market, with an annual output of more than 200 million tons. It is the largest single chemical product in the world today. It has a wide range of manufacturing and distribution infrastructure worldwide, which is sufficient to ensure an uninterrupted supply of fuel. Ammonia has little environmental harm. At the same time, ammonia undergoes thermal cracking reaction after absorbing heat. In the temperature range of 520-690℃, the NH3 conversion rate on Ni-Pt / Al2O3 catalyst is higher than 80%. Its high hydrogen conversion rate and operating temperature are very compatible with solid oxide fuel cells.

[0004] A fuel cell is a device that converts the chemical energy of a fuel directly into electrical energy. It is not limited by the Carnot cycle and therefore has a high power generation efficiency. Solid oxide fuel cells operate at a high temperature and have the advantages of a wide range of fuel applications, long service life, and low maintenance costs.

[0005] Combining efficient fuel cell technology with electric boost technology for jet propulsion systems has great potential. This combination can improve the efficiency and performance of jet propulsion systems while reducing dependence on traditional fuels, and is expected to promote technological innovation and sustainable development in the aerospace industry. Summary of the invention

[0006] In view of this, in order to solve the problems of excessive total temperature of incoming air at high Mach number of the aircraft limiting the workmanship of the compressor, resulting in poor engine variable operating performance, difficulty in matching the compressor and the turbine, low working efficiency, and waste of fuel, the present invention proposes an ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system. The system drives the secondary compressor to assist in supercharging, increase the power generation of the body, and achieve energy quality transition through an electric motor, thereby improving the specific impulse, fuel utilization efficiency and energy utilization rate of the engine, and promoting the reliability, practicality and militarization of precooling and power generation technology.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system, comprising an air inlet, a first splitter, an aviation kerosene precooler, a liquid ammonia precooler, a confluence, a compressor, a main combustion chamber, a turbine, an afterburner, a tail nozzle, an aviation kerosene storage tank, an aviation kerosene valve, an aviation kerosene pump, a second splitter, a liquid ammonia storage tank, a liquid ammonia valve, a liquid ammonia pump, a third splitter, a solid oxide fuel cell system, an electric motor, a secondary compressor and an aircraft load;

[0008] The outlet of the air inlet is connected to the inlet of the first splitter, the two outlet ends of the first splitter are respectively connected to the hot end inlets of the aviation kerosene precooler and the liquid ammonia precooler, the hot end outlets of the aviation kerosene precooler and the liquid ammonia precooler are respectively connected to the two inlet ends of the merger, the outlet of the merger is connected to the inlet of the compressor, the outlet of the compressor is connected to the secondary compressor, the outlet of the secondary compressor is connected to the inlet of the main combustion chamber, the outlet of the main combustion chamber is connected to the inlet of the turbine, the outlet of the turbine is connected to the outlet of the afterburner, and the outlet of the afterburner is connected to the inlet of the tail nozzle,

[0009] The outlet of the aviation kerosene storage tank is connected to the aviation kerosene valve, the outlet of the aviation kerosene valve leads to the aviation kerosene pump, the outlet of the aviation kerosene pump is connected to the cold end inlet of the aviation kerosene precooler, the cold end outlet of the aviation kerosene precooler is connected to the inlet of the second splitter, and the two outlets of the second splitter are respectively connected to the inlet of the main combustion chamber and the inlet of the afterburner.

[0010] The outlet of the liquid ammonia storage tank is connected to the liquid ammonia valve, the outlet of the liquid ammonia valve is connected to the liquid ammonia pump, the outlet of the liquid ammonia pump is connected to the cold end inlet of the liquid ammonia precooler, the cold end outlet of the liquid ammonia precooler is connected to the inlet of the third diverter, the three outlets of the third diverter are respectively connected to the main combustion chamber inlet, the afterburner inlet and the anode inlet of the solid oxide fuel cell system, the cathode inlet of the solid oxide fuel cell system is connected to the third outlet of the first diverter, the exhaust gas from the anode and cathode outlets of the solid oxide fuel cell system is connected to the tail nozzle, the electric energy generated by the solid oxide fuel cell system is supplied to the aircraft load and the motor, and the motor is coaxially connected to the secondary compressor.

[0011] Furthermore, the size of the air inlet of the air inlet duct is adjustable.

[0012] Furthermore, the aviation kerosene precooler and the liquid ammonia precooler are partition-type heat exchangers, and the air is cooled by the fuel in the precooler, and the structure thereof is a serpentine tube bundle type or an involute type.

[0013] Furthermore, the tube wall of the liquid ammonia precooler is coated with a high-activity catalyst to facilitate the thermal cracking reaction of the liquid ammonia to absorb more heat.

[0014] Furthermore, the aviation kerosene precooler and the liquid ammonia precooler are arranged in parallel.

[0015] Furthermore, the ratio of the outlet flow rates of the first flow splitter, the second flow splitter and the third flow splitter is adjustable.

[0016] Furthermore, the tail nozzle is a Laval nozzle, and the nozzle geometry is adjustable.

[0017] Furthermore, the solid oxide fuel cell system is composed of a plurality of metal-supported solid oxide fuel cell stacks, and each metal-supported solid oxide fuel cell stack is composed of a plurality of metal-supported solid oxide fuel cells connected in series.

[0018] Furthermore, when the aircraft flies at a specific Mach number, the flow rate of liquid ammonia required to cool the incoming air is greater than the flow rate of liquid ammonia required for proper combustion, thereby causing a partial waste of liquid ammonia. At this time, the cracking rate of liquid ammonia is extremely high, and the cracking products are mostly hydrogen. At the same time, the temperature of the ammonia cracking gas after heat exchange with the incoming air is relatively high, and it is passed into the anode of the solid oxide fuel cell system to generate electricity. At the same time, the first diverter is opened and the size of the air inlet of the air inlet duct is increased, thereby ensuring that the air entering this system can not only meet the air consumption required by multiple combustion chambers, but also that there is remaining air to enter the cathode of the solid oxide fuel cell system to react exactly with the ammonia cracking gas passed into the anode, thereby maximizing energy utilization.

[0019] Compared with the prior art, the beneficial effects of the ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system of the present invention are:

[0020] 1. The present invention adopts a dual-fuel pre-cooling propulsion method, and selects liquid ammonia and aviation kerosene as the dual fuels of the system. Liquid ammonia has a high heat sink but a low calorific value, while aviation kerosene has a high calorific value but a small heat sink. Such a design can not only meet the heat sink requirements for pre-cooling the incoming air, but also meet the fuel calorific value requirements required for the aircraft to fly at a high Mach number, thereby making it possible for the aircraft to fly stably and safely at hypersonic speeds.

[0021] 2. When the aircraft of the present invention flies at a specific Mach number, the flow rate of liquid ammonia required to cool the incoming air is greater than the flow rate of liquid ammonia required for proper combustion, thereby causing excess liquid ammonia. Through the participation of solid oxide fuel cells, the wasted liquid ammonia is reused without residual fuel, and this part of energy is transferred from thermal energy to electrical energy, thereby improving energy quality and increasing the energy conversion rate of the system.

[0022] 3. The present invention supplies the electrical energy produced by the solid oxide fuel cell system to the aircraft load and the electric motor, and the electric motor drives the secondary compressor to work by being installed coaxially with the secondary compressor, thereby changing the previous single-stage compression into multi-stage compression, which can not only meet the higher exhaust pressure of the system but also improve the overall efficiency of the compressor, increase the flexibility and adaptability of the system, and effectively solve the problem of difficulty in adapting the turbine and compressor and poor performance under variable operating conditions.

[0023] 4. The present invention adopts liquid ammonia and aviation kerosene dual fuel design, which effectively reduces the problem of high carbon emissions of aircraft. Ammonia is a good carrier of hydrogen, and hydrogen energy is a zero-carbon green secondary energy source, which proposes new possibilities for the subsequent development direction of aerospace.

[0024] 5. The present invention is a system based on a dual-fuel precooling engine that passes excess precooling fuel into a solid oxide fuel cell to drive a secondary compressor to perform secondary supercharging of the incoming air or supply electricity to an electrical load. The scheme is based on a jet propulsion system that uses a dual-fuel precooling engine and a fuel cell to generate electricity. The solid oxide fuel cell directly converts thermal energy into electrical energy, and the electric motor drives the secondary compressor to perform secondary supercharging of the air. It can also provide electrical energy for the aircraft load, enabling the aircraft to sail for a long time and providing electricity guarantee for equipping the aircraft with militarized weapons. After the mixed gas is mixed and burned in the combustion chamber and the afterburner, it is discharged through the nozzle together with the exhaust gas of the solid oxide fuel cell to generate thrust. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of an ammonia / kerosene dual-fuel precooling engine and a fuel cell power generation system according to an embodiment of the present invention;

[0027] Explanation of the reference numerals in the figures: 1-inlet duct, 2-first diverter, 3-aviation kerosene precooler, 4-liquid ammonia precooler, 5-merger, 6-compressor, 7-main combustion chamber, 8-turbine, 9-afterburner, 10-tail nozzle, 11-aviation kerosene storage tank, 12-aviation kerosene valve, 13-aviation kerosene pump, 14-second diverter, 15-liquid ammonia storage tank, 16-liquid ammonia valve, 17-liquid ammonia pump, 18-third diverter, 19-solid oxide fuel cell system, 20-electric motor, 21-secondary compressor, 22-aircraft load. Specific implementation methods

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0030] See also Figure 1 The present implementation method is described, an ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system, including an air inlet 1, a first diverter 2, an aviation kerosene precooler 3, a liquid ammonia precooler 4, a combiner 5, a compressor 6, a main combustion chamber 7, a turbine 8, an afterburner 9, a tail nozzle 10, an aviation kerosene storage tank 11, an aviation kerosene valve 12, an aviation kerosene pump 13, a second diverter 14, a liquid ammonia storage tank 15, a liquid ammonia valve 16, a liquid ammonia pump 17, a third diverter 18, a solid oxide fuel cell system 19, an electric motor 20, a secondary compressor 21 and an aircraft load 22.

[0031] When the aircraft is flying, incoming air enters the air inlet 1, the outlet of the air inlet 1 is connected to the inlet of the first splitter 2, the two outlet ends of the first splitter 2 are respectively connected to the hot end inlets of the aviation kerosene precooler 3 and the liquid ammonia precooler 4, the hot end outlets of the aviation kerosene precooler 3 and the liquid ammonia precooler 4 are respectively connected to the two inlet ends of the merger 5, the outlet of the merger 5 is connected to the inlet of the compressor 6, the outlet of the compressor 6 is connected to the secondary compressor 21, the outlet of the secondary compressor 21 is connected to the inlet of the main combustion chamber 7, the outlet of the main combustion chamber 7 is connected to the inlet of the turbine 8, the outlet of the turbine 8 is connected to the outlet of the afterburner 9, and the outlet of the afterburner 9 is connected to the inlet of the tail nozzle 10. The compressed air at the outlet of the compressor 6 is passed into the secondary compressor 21 and then enters the main combustion chamber 7 for combustion, and then enters the turbine 8 for power generation. The mixer at the outlet of the turbine 8 enters the afterburner 9, and finally enters the tail nozzle 10 for expansion and work.

[0032] The outlet of the aviation kerosene storage tank 11 is connected to the aviation kerosene valve 12, the outlet of the aviation kerosene valve 12 leads to the aviation kerosene pump 13, the outlet of the aviation kerosene pump 13 is connected to the cold end inlet of the aviation kerosene precooler 3, the cold end outlet of the aviation kerosene precooler 3 is connected to the inlet of the second diverter 14, and the two outlets of the second diverter 14 are respectively connected to the inlet of the main combustion chamber 7 and the inlet of the afterburner 9.

[0033] The aviation kerosene storage tank 11 and the liquid ammonia storage tank 15 are respectively connected to valves and then enter the pump for pressurization and are respectively connected to the cold end inlets of the aviation kerosene precooler 3 and the liquid ammonia precooler 4. The outlet of the liquid ammonia storage tank 15 is connected to the liquid ammonia valve 16, and the outlet of the liquid ammonia valve 16 leads to the liquid ammonia pump 17. The outlet of the liquid ammonia pump 17 is connected to the cold end inlet of the liquid ammonia precooler 4, and the cold end outlet of the liquid ammonia precooler 4 is connected to the inlet of the third diverter 18.

[0034] One outlet of the third diverter 18 is connected to the inlet end of the main combustion chamber 5; another outlet is connected to the inlet of the afterburner 7; the last outlet is connected to the anode inlet end of the solid oxide fuel cell system 19, and the air is passed from the first diverter 2 to the cathode inlet end of the solid oxide fuel cell system 19. The anode and cathode outlet exhaust gases of the solid oxide fuel cell system 19 are connected to the inlet end of the tail nozzle 10. The electric energy provided by the solid oxide fuel cell system 19 is passed into the electric motor 20 and the aircraft load 22, and the electric motor 20 drives the secondary compressor 21 to do work.

[0035] In this embodiment, the size of the air inlet of the air inlet duct 1 is adjustable, which ensures that the air mass flow rate of the engine meets the preset value while achieving effective compression of the incoming air, thereby coping with different flight conditions.

[0036] In this embodiment, the aviation kerosene precooler 3 and the liquid ammonia precooler 4 are wall-type heat exchangers, and the air is cooled by the fuel in the precooler. The structure can be a serpentine tube bundle type or an involute type; at the same time, the tube wall of the liquid ammonia precooler 4 is coated with a high-activity catalyst to facilitate the thermal cracking reaction of liquid ammonia to absorb more heat. The two precoolers are arranged in parallel. Compared with the series arrangement, the temperature difference between the hot end and the cold end is larger, and the heat exchange effect is better. This system adopts a dual-fuel precooling and combustion operation mode, which can not only meet the heat sink requirements for precooling the incoming air, but also meet the fuel calorific value requirements required for high Mach number flight of the aircraft.

[0037] In this embodiment, the outlet flow ratios of the first splitter 2, the second splitter 14 and the third splitter 18 are adjustable so that the aircraft can adjust to different pre-cooling requirements when operating at different speeds and altitudes. When the aircraft flies at a high Mach number, the cooling capacity of the incoming air is met by increasing the liquid ammonia flow rate, thereby achieving stable and safe operation of the aircraft at a high Mach number. The present invention can achieve stable flight of the aircraft at hypersonic speed.

[0038] In this embodiment, the solid oxide fuel cell system 19 is composed of a plurality of metal-supported solid oxide fuel cell stacks, and each metal-supported solid oxide fuel cell stack is composed of a plurality of metal-supported solid oxide fuel cells connected in series.

[0039] When the aircraft flies at a specific Mach number, the flow rate of liquid ammonia required to cool the incoming air is greater than the flow rate of liquid ammonia required for proper combustion, resulting in a partial waste of liquid ammonia. At this time, the cracking rate of liquid ammonia is extremely high, and the cracking products are mostly hydrogen. At the same time, the temperature of the ammonia cracking gas after heat exchange with the incoming air is relatively high. Not only in terms of reaction temperature but also in terms of reactants of solid oxide fuel cells, the liquid ammonia pre-cooling fuel is very compatible with the solid oxide fuel cell power generation system. Therefore, it is introduced into the anode of the solid oxide fuel cell system 19 to generate electricity. At the same time, the first diverter 2 is opened and the size of the air inlet of the air inlet duct is increased to ensure that the air entering this system can not only meet the air consumption required by multiple combustion chambers, but also that there is remaining air to enter the cathode of the solid oxide fuel cell system 19 to react exactly with the ammonia cracking gas introduced into the anode, thereby maximizing energy utilization.

[0040] The present invention reuses the wasted liquid ammonia, leaving no fuel left, and transfers this part of energy from thermal energy to electrical energy, thereby improving the energy quality and the energy conversion rate of the system. The present invention reuses the wasted liquid ammonia, leaving no fuel left, and transfers this part of energy from thermal energy to electrical energy, thereby improving the energy quality and the energy conversion rate of the system.

[0041] In this embodiment, the solid oxide fuel cell system 19 provides electric energy for the motor 20, which is coaxially connected to the secondary compressor 21 and drives the secondary compressor 21 to work, thereby realizing multi-stage compression, which can not only meet the higher exhaust pressure of the system but also improve the overall efficiency of the compressor, increase the flexibility and adaptability of the system, and effectively solve the problem of the difficulty in adapting the turbine 5 and the compressor. At the same time, the electric energy generated by the solid oxide fuel cell system 19 can not only be applied to the secondary compressor 21, but also can be provided to the aircraft load 22, wherein the flight load 22 can be an aircraft control system, laser weapons, radars, or can provide electricity needs for passengers when used as a civil aircraft.

[0042] In this embodiment, the tail nozzle 10 is a Laval nozzle, and the nozzle geometry is adjustable to obtain the maximum thrust.

[0043] The working principle of the ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system of the present invention is:

[0044] When the propulsion system is working, the air from the environment is initially compressed through the air inlet 1 and then enters the first splitter 2. The splitter 2 and the compressed air from the incoming flow are respectively passed into the aviation kerosene precooler 3 and the liquid ammonia precooler 4, so that they exchange heat with the pressurized aviation kerosene and liquid ammonia respectively, thereby cooling the high-temperature incoming air. The air after heat exchange is merged through the merger 5 and then enters the compressor 6 for supercharging, and then enters the secondary compressor 21 for secondary supercharging. The air after secondary supercharging is passed into the main combustion chamber 7 together with the aviation kerosene fuel flowing out of the second splitter 5 and the liquid ammonia fuel flowing out of the third splitter 18 for combustion. The mixer after combustion is passed into the turbine 8 for expansion and work, driving the compressor 6 to do work on the air after heat exchange from the incoming flow. The mixed gas flowing out of the turbine 8, the aviation kerosene fuel flowing out of the second splitter 5 and the liquid ammonia fuel flowing out of the third splitter 18 enter the afterburner 9 together with the aviation kerosene fuel flowing out of the second splitter 5 and the liquid ammonia fuel flowing out of the third splitter 18 for full combustion, and then passes into the tail nozzle 10 for acceleration and discharge to generate thrust.

[0045] When there is excess liquid ammonia precooling fuel, the third channel of the first diverter 2 is opened to pass part of the incoming high-temperature air into the cathode of the solid oxide fuel cell system 19. At the same time, the third channel of the third diverter 18 is opened to pass excess liquid ammonia into the anode of the solid oxide fuel cell system 19. The electric energy produced by the solid oxide fuel cell system 19 can power the aircraft load 22 and the electric motor 20, and the electric motor 20 is coaxially connected to the secondary compressor 21, which can drive the secondary compressor 21 to do work, thereby forming a multi-stage compression system.

[0046] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. An ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system, characterized in that: The invention comprises an air inlet (1), a first flow divider (2), an aviation kerosene precooler (3), a liquid ammonia precooler (4), a flow combiner (5), a compressor (6), a main combustion chamber (7), a turbine (8), an afterburner (9), a tail nozzle (10), an aviation kerosene storage tank (11), an aviation kerosene valve (12), an aviation kerosene pump (13), a second flow divider (14), a liquid ammonia storage tank (15), a liquid ammonia valve (16), a liquid ammonia pump (17), a third flow divider (18), a solid oxide fuel cell system (19), an electric motor (20), a secondary compressor (21) and an aircraft load (22); The outlet of the air inlet duct (1) is connected to the inlet of the first flow splitter (2), the two outlet ends of the first flow splitter (2) are respectively connected to the hot end inlets of the aviation kerosene precooler (3) and the liquid ammonia precooler (4), the hot end outlets of the aviation kerosene precooler (3) and the liquid ammonia precooler (4) are respectively connected to the two inlet ends of the flow merger (5), the outlet of the flow merger (5) is connected to the inlet of the compressor (6), the outlet of the compressor (6) is connected to the secondary compressor (21), the outlet of the secondary compressor (21) is connected to the inlet of the main combustion chamber (7), the outlet of the main combustion chamber (7) is connected to the inlet of the turbine (8), the outlet of the turbine (8) is connected to the outlet of the afterburner (9), and the outlet of the afterburner (9) is connected to the inlet of the tail nozzle (10), The outlet of the aviation kerosene storage tank (11) is connected to the aviation kerosene valve (12), the outlet of the aviation kerosene valve (12) leads to the aviation kerosene pump (13), the outlet of the aviation kerosene pump (13) is connected to the cold end inlet of the aviation kerosene precooler (3), the cold end outlet of the aviation kerosene precooler (3) is connected to the inlet of the second splitter (14), and the two outlets of the second splitter (14) are respectively connected to the inlet of the main combustion chamber (7) and the inlet of the afterburner (9), The outlet of the liquid ammonia storage tank (15) is connected to the liquid ammonia valve (16), the outlet of the liquid ammonia valve (16) is connected to the liquid ammonia pump (17), the outlet of the liquid ammonia pump (17) is connected to the cold end inlet of the liquid ammonia precooler (4), the cold end outlet of the liquid ammonia precooler (4) is connected to the inlet of the third diverter (18), the three outlets of the third diverter (18) are respectively connected to the inlet of the main combustion chamber (7), the inlet of the afterburner (9) and the anode inlet of the solid oxide fuel cell system (19), the cathode inlet of the solid oxide fuel cell system (19) is connected to the third outlet of the first diverter (2), the exhaust gas at the anode and cathode outlets of the solid oxide fuel cell system (19) is connected to the tail nozzle (10), the electric energy generated by the solid oxide fuel cell system (19) is supplied to the aircraft load (22) and the motor (20), and the motor (20) is coaxially connected to the secondary compressor (21).

2. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1, characterized in that: The size of the air inlet of the air inlet duct (1) is adjustable.

3. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1, characterized in that: The aviation kerosene precooler (3) and the liquid ammonia precooler (4) are partition-type heat exchangers, and the air is cooled by the fuel in the precooler. The structure is a serpentine tube bundle type or an involute type.

4. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1, characterized in that: The tube wall of the liquid ammonia precooler (4) is coated with a high-activity catalyst to facilitate the thermal cracking reaction of the liquid ammonia to absorb more heat.

5. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1 or 3, characterized in that: The aviation kerosene precooler (3) and the liquid ammonia precooler (4) are arranged in parallel.

6. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1, characterized in that: The ratio of the outlet flow rates of the first flow splitter (2), the second flow splitter (14) and the third flow splitter (18) is adjustable.

7. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1, characterized in that: The tail nozzle (10) is a Laval nozzle, and the nozzle geometry structure is adjustable.

8. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1, characterized in that: The solid oxide fuel cell system (19) is composed of a plurality of metal-supported solid oxide fuel cell stacks, each of which is composed of a plurality of metal-supported solid oxide fuel cells connected in series.

9. The ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system according to claim 1, characterized in that: When the aircraft flies at a specific Mach number, the flow rate of liquid ammonia required to cool the incoming air is greater than the flow rate of liquid ammonia required for proper combustion, resulting in a partial waste of liquid ammonia. At this time, the cracking rate of liquid ammonia is extremely high, and the cracking products are mostly hydrogen. At the same time, the temperature of the ammonia cracking gas after heat exchange with the incoming air is relatively high. It is passed into the anode of the solid oxide fuel cell system (19) to generate electricity. At the same time, the first diverter (2) is opened and the size of the air inlet of the air inlet duct is increased, thereby ensuring that the air entering this system can not only meet the air consumption required by multiple combustion chambers, but also that there is surplus air that can enter the cathode of the solid oxide fuel cell system (19) to react exactly with the ammonia cracking gas passed into the anode, thereby maximizing energy utilization.

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