An ammonia / kerosene dual-fuel pre-cooling engine and fuel cell power generation system

Abstract

The present invention proposes an ammonia / kerosene dual-fuel pre-cooling engine and fuel cell power generation system, which belongs to the field of aviation system technology. It solves the problems of excessively high total temperature of incoming air at high Mach number of aircraft, which limits the operation of the compressor and leads to poor engine variable operating performance, difficulty in matching the compressor and turbine, low working efficiency, and fuel waste. The present invention supplies the electric 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, thus changing the previous single-stage compression into multi-stage compression. 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, which 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 high Mach number, thereby making it possible for the aircraft to fly stably and safely at hypersonic speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of aviation systems, and in particular relates to an ammonia / kerosene dual-fuel pre-cooling 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 transport systems is engine technology, with air-precooled combined engines a key research area. By installing a precooler at the compressor inlet and using fuel cooling to lower the inlet air temperature, compressor power consumption can be significantly reduced, thereby improving engine cycle efficiency.

[0003] Ammonia is a hydrogen-rich gas. Compared to hydrogen, it has a higher volumetric energy density, is easier to liquefy, store, and transport, and is safer, more economical, and less environmentally hazardous than other common fuels. Furthermore, ammonia is in ample supply, with annual production exceeding 200 million tons, making it the world's most consumed single chemical product. A global manufacturing and distribution infrastructure is extensive, ensuring an uninterrupted supply of the fuel. Furthermore, ammonia absorbs heat and undergoes thermal cracking. Within the temperature range of 520-690°C, ammonia conversion rates on Ni-Pt / Al2O3 catalysts exceed 80%. Its high hydrogen conversion rate and operating temperature are well-suited for solid oxide fuel cells.

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

[0005] Combining efficient fuel cell technology with electric supercharging for jet propulsion systems holds enormous potential. This combination can improve the efficiency and performance of jet propulsion systems while reducing reliance on traditional fuels, potentially driving technological innovation and sustainable development in the aerospace sector. 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 numbers of aircraft, which limits the workmanship of the compressor and leads to poor engine performance in variable operating conditions, difficulty in matching the compressor and turbine, low working efficiency, and fuel waste, the present invention proposes an ammonia / kerosene dual-fuel pre-cooling engine and fuel cell power generation system. The system uses an electric motor to drive the secondary compressor to assist in boosting, increase the power generation of the body, and achieve energy quality transition, thereby improving the engine's specific impulse, fuel utilization efficiency and energy utilization rate, and promoting the reliability, practicality and militarization of pre-cooling and power generation technology.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions: an ammonia / kerosene dual-fuel precooling engine and fuel cell power generation system, comprising an air intake, a first flow divider, an aviation kerosene precooler, a liquid ammonia precooler, a flow combiner, 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 flow divider, a liquid ammonia storage tank, a liquid ammonia valve, a liquid ammonia pump, a third flow divider, 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 is connected 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 electric motor, and the electric 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 splitter, the second splitter and the third 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, resulting in the waste of some 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 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 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 residual air to enter the cathode of the solid oxide fuel cell system and react 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 pre-cooling 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, selecting liquid ammonia and aviation kerosene as the system's dual fuels. Liquid ammonia has a high heat sink but a low calorific value, while aviation kerosene has a high calorific value but a low heat sink. This design not only meets the heat sink requirements for pre-cooling the incoming air, but also meets the fuel calorific value requirements for high Mach number flight, thereby enabling 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, resulting in excess liquid ammonia. Through the participation of the solid oxide fuel cell, the wasted liquid ammonia is reused, leaving no fuel remaining, and this part of the energy is transitioned from thermal energy to electrical energy, thereby improving the 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. The electric motor drives the secondary compressor to work by being installed coaxially with the secondary compressor, transforming the previous single-stage compression into multi-stage compression. This not only meets the system's higher exhaust pressure but also improves the overall efficiency of the compressor, increases the system's flexibility and adaptability, and effectively solves the problems of difficult adaptation of the turbine and compressor and poor performance under variable operating conditions.

[0023] 4. The present invention adopts a dual-fuel design of liquid ammonia and aviation kerosene, 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, which proposes new possibilities for the subsequent development of aerospace.

[0024] 5. The present invention is a system based on a dual-fuel pre-cooling engine that passes excess pre-cooling fuel into a solid oxide fuel cell, thereby driving a secondary compressor to perform secondary supercharging of the incoming air or supply electricity to electrical loads. This solution is based on a jet propulsion system that uses a dual-fuel pre-cooling engine and fuel cell power generation. The solid oxide fuel cell directly converts thermal energy into electrical energy, and an electric motor drives the secondary compressor to perform secondary supercharging of the air. This system can also provide electrical energy for aircraft loads, enabling long-term flight for the aircraft and providing power for equipping the aircraft with military weapons. After the mixed gas is mixed and burned in the combustion chamber and afterburner, it is accelerated and discharged through the nozzle together with the solid oxide fuel cell exhaust, generating thrust. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0027] Explanation of the reference numerals: 1-air inlet, 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

[0028] The following will be combined with the accompanying 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 therein can be combined with each other in the absence of conflict, and the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0029] See also Figure 1 To illustrate the present embodiment, an ammonia / kerosene dual-fuel pre-cooling engine and fuel cell power generation system includes an air inlet 1, a first diverter 2, an aviation kerosene pre-cooler 3, a liquid ammonia pre-cooler 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.

[0030] When the aircraft is flying, incoming air enters the air inlet 1, and 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, and 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, and 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 to generate electricity. The mixer at the outlet of the turbine 8 enters the afterburner 9, and finally enters the tail nozzle 10 to expand and do work.

[0031] 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 is connected 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.

[0032] The aviation kerosene storage tank 11 and the liquid ammonia storage tank 15 are respectively connected to valves and 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 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, and the cold end outlet of the liquid ammonia precooler 4 is connected to the inlet of the third diverter 18.

[0033] 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 end 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.

[0034] 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.

[0035] In this embodiment, the kerosene precooler 3 and the liquid ammonia precooler 4 are wall-type heat exchangers, where the air is cooled by the fuel. The structure can be either a serpentine tube bundle or an involute tube. Furthermore, the tube walls of the liquid ammonia precooler 4 are coated with a highly active catalyst, facilitating the thermal cracking reaction of the liquid ammonia to absorb more heat. The two precoolers are arranged in parallel, which, compared to a series arrangement, results in a greater temperature difference between the hot and cold ends and better heat exchange. This system utilizes dual-fuel precooling and combustion, which not only meets the heat sink requirements for precooling the incoming air but also meets the fuel calorific value requirements for high Mach number flight.

[0036] 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 liquid ammonia flow rate is increased to meet the cooling capacity of the incoming air, 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 speeds.

[0037] 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.

[0038] 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 waste of some 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 the solid oxide fuel cell, 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 and generates 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 and react with the ammonia cracking gas introduced into the anode, thereby maximizing energy utilization.

[0039] The present invention reuses wasted liquid ammonia, leaving no fuel remaining, and converts this energy from thermal energy to electrical energy, improving energy quality and increasing the energy conversion rate of the system. The present invention reuses wasted liquid ammonia, leaving no fuel remaining, and converts this energy from thermal energy to electrical energy, improving energy quality and increasing the energy conversion rate of the system.

[0040] In this embodiment, the solid oxide fuel cell system 19 provides electrical energy to an electric motor 20, which is coaxially connected to a secondary compressor 21 and drives the secondary compressor 21 to operate, thereby achieving multi-stage compression. This not only meets the system's higher exhaust pressure but also improves the overall efficiency of the compressor, increasing system flexibility and adaptability, and effectively resolving the problem of difficult compatibility between the turbine 5 and the compressor. Furthermore, the electrical energy generated by the solid oxide fuel cell system 19 can be used not only for the secondary compressor 21 but also for aircraft loads 22. These loads can include aircraft control systems, laser weapons, radar, or, in the case of civilian aircraft, passengers.

[0041] In this embodiment, the tail nozzle 10 is a Laval nozzle, and the nozzle geometry is adjustable to obtain maximum thrust.

[0042] The working principle of the ammonia / kerosene dual-fuel pre-cooling engine and fuel cell power generation system of the present invention is:

[0043] When the propulsion system is working, air from the environment is initially compressed after passing through the air inlet 1 and enters the first splitter 2. The splitter 2 passes the compressed incoming air into the aviation kerosene precooler 3 and the liquid ammonia precooler 4 respectively, so that it exchanges 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 enters the compressor 6 for supercharging, and then passes into the secondary compressor 21 for secondary supercharging. The air after secondary supercharging, the aviation kerosene fuel flowing out of the second splitter 5, and the liquid ammonia fuel flowing out of the third splitter 18 are passed into the main combustion chamber 7 for combustion. The mixed gas after combustion is passed into the turbine 8 for expansion and work, driving the compressor 6 to do work on the incoming air after heat exchange. 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, for full combustion, and then passes into the tail nozzle 10 for acceleration and discharge, generating thrust.

[0044] When there is excess liquid ammonia pre-cooling 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.

[0045] The embodiments of the present invention disclosed above are intended only to illustrate the present invention. These embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific implementation methods described. Numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. An ammonia / kerosene dual-fuel pre-cooling engine and fuel cell power generation system, characterized by: 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 combiner (5), the outlet of the flow combiner (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) is connected 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). 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 from the anode and cathode outlets of the solid oxide fuel cell system (19) is connected to the tail nozzle (10), and the electric energy generated by the solid oxide fuel cell system (19) is supplied to the aircraft load (22) and the electric motor (20), and the electric motor (20) is coaxially connected to the secondary compressor (21).

2. The ammonia / kerosene dual-fuel pre-cooling 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 pre-cooling 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 pre-cooling 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, which facilitates the thermal cracking reaction of the liquid ammonia to absorb more heat.

5. The ammonia / kerosene dual-fuel pre-cooling 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 pre-cooling engine and fuel cell power generation system according to claim 1, characterized in that: The outlet flow ratios of the first flow splitter (2), the second flow splitter (14) and the third flow splitter (18) are adjustable.

7. The ammonia / kerosene dual-fuel pre-cooling 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 is adjustable.

8. The ammonia / kerosene dual-fuel pre-cooling 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, and each metal-supported solid oxide fuel cell stack is composed of a plurality of metal-supported solid oxide fuel cells connected in series.

9. The ammonia / kerosene dual-fuel pre-cooling 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 waste of some 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 residual air that can enter the cathode of the solid oxide fuel cell system (19) and react with the ammonia cracking gas passed into the anode, thereby maximizing energy utilization.

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