Liquid ammonia aviation kerosene dual-fuel hybrid turbofan engine combined with fuel cell for power generation

Abstract

The invention discloses a liquid ammonia and aviation kerosene dual-fuel hybrid turbofan engine combined with a fuel cell for power generation, which belongs to the technical field of aero-engines and comprises a traditional turbofan core machine, a liquid ammonia fuel subsystem, an aviation kerosene fuel subsystem and a fuel cell power supply subsystem, and the liquid ammonia fuel subsystem, the aviation kerosene fuel subsystem and the fuel cell power supply subsystem are integrated. Liquid ammonia is conveyed to the liquid ammonia preheater through the fuel pump, absorbs heat of air from an outlet of the low-pressure compressor and is vaporized, and cooling of air at an inlet of the high-pressure compressor is achieved; vaporized ammonia gas enters an ammonia gas decomposition hydrogen production device which annularly sleeves the outer wall of the exhaust nozzle, and is catalytically decomposed into hydrogen gas by utilizing waste heat of the exhaust nozzle; high-temperature mixed gas generated by decomposition enters an aviation fuel preheater for preheating aviation fuel and then is conveyed to an anode of the proton exchange membrane fuel cell; and meanwhile, part of the air cooled by the liquid ammonia preheater is conveyed to the cathode of the fuel cell through a pressure reducing valve. The thrust loss caused by extracting power from the main shaft of the engine is avoided, and the energy comprehensive utilization efficiency of the whole engine is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine system technology, and in particular to turbofan engines based on hybrid power systems. It is mainly used to solve problems such as the increasing power requirements of airborne electrical equipment in existing turbofan engines and the difficulty in extracting electrical power from the engine main shaft. Background Technology

[0002] In recent years, technological innovation in civil aviation engines has continued to move towards lower fuel consumption, lower emissions, more compact structures, and higher reliability. With the increasing number of airborne electrical systems such as avionics, electric actuators, and environmental control systems, the demand for electrical power has also increased significantly. Traditional turbofan engines typically power airborne equipment by extracting mechanical energy from the engine shaft and converting it into electrical energy. This method not only increases the engine's mechanical complexity and transmission losses but also consumes propulsion power, leading to a decrease in engine thrust and propulsion efficiency.

[0003] To address these challenges, hybrid power systems have gradually become a research hotspot in the field of aero-engines. Among them, fuel cell systems have attracted much attention due to their high efficiency and low emissions. In particular, proton exchange membrane fuel cells, which emit only water vapor and unreacted air during operation, have the potential for zero carbon emissions. If they can replace some traditional aviation kerosene, they can significantly reduce greenhouse gas emissions from engines. However, hydrogen fuel cells still face problems in practical applications, such as low hydrogen storage density, large tank volume, and increased system weight, which directly affect the power-to-weight ratio and range performance of aircraft.

[0004] To address the challenges of hydrogen storage, liquid ammonia is considered a promising hydrogen carrier due to its high volumetric hydrogen storage density, relatively mature storage and transportation infrastructure, and low cost. Through catalytic decomposition, liquid ammonia can release hydrogen at lower temperatures, which can then be used in fuel cells. Furthermore, liquid ammonia exhibits strong endothermic properties during vaporization and decomposition, which can be used for engine thermal management, improving the overall thermal efficiency of the system.

[0005] While existing research has explored the use of liquid ammonia for aircraft propulsion or auxiliary power generation, a systematic solution remains lacking for how to deeply integrate it with existing turbofan engines to achieve multiple optimizations in waste heat recovery, power extraction, and emission control. In particular, achieving a highly efficient, stable, and lightweight hybrid power configuration without increasing the main shaft load or significantly altering the engine's main structure is a critical technological bottleneck that urgently needs to be overcome in the field of aero-engines.

[0006] Therefore, it is necessary to develop a new type of liquid ammonia / aviation kerosene dual-fuel hybrid power system. By integrating multiple technologies such as fuel cell power generation, exhaust nozzle waste heat utilization, liquid ammonia intercooling and fuel preheating, the system can meet the growing airborne power demand while improving the engine's propulsion performance, thermal efficiency and environmental friendliness. Summary of the Invention

[0007] In view of this, the present invention provides a liquid ammonia-jet dual-fuel hybrid turbofan engine that combines fuel cell power generation to meet the power requirements of airborne electrical equipment of the next generation of turbofan engines, reduce greenhouse gas emissions of turbofan engines, and improve engine thrust and thermal efficiency.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A dual-fuel hybrid turbofan engine combining a liquid ammonia and aviation kerosene for power generation via a fuel cell includes: an air intake, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, and an exhaust nozzle connected sequentially along the airflow direction; it also includes a liquid ammonia fuel subsystem, an aviation kerosene fuel subsystem, and a fuel cell power supply system. The liquid ammonia fuel subsystem includes a liquid ammonia storage tank, a liquid ammonia fuel pump, a cold side channel of a liquid ammonia preheater, and an ammonia decomposition hydrogen generator connected in sequence by pipelines. The aviation kerosene fuel subsystem includes an aviation kerosene storage tank, an aviation kerosene fuel pump, and a cold-side passage of an aviation kerosene preheater connected in sequence by pipelines. The outlet of the cold-side passage of the aviation kerosene preheater is connected to the fuel inlet of the combustion chamber. The fuel cell power supply system includes a proton exchange membrane fuel cell and a pressure reducing valve; Wherein: the outlet of the low-pressure compressor is connected to the inlet of the hot side channel of the liquid ammonia preheater, and the outlet of the hot side channel of the liquid ammonia preheater is divided into two paths: one path is connected to the inlet of the high-pressure compressor, and the other path is connected to the cathode inlet of the proton exchange membrane fuel cell via the pressure reducing valve; The outlet of the ammonia decomposition hydrogen generator is connected to the inlet of the hot side channel of the jet fuel preheater, and the outlet of the hot side channel of the jet fuel preheater is connected to the anode inlet of the proton exchange membrane fuel cell.

[0010] Through the above technical solution, the engine system provided by this invention highly integrates a liquid ammonia fuel subsystem, a jet fuel subsystem, and a fuel cell power supply system. Liquid ammonia is used simultaneously as both a hydrogen source and an intercooler, and hydrogen is produced by decomposing waste heat from the exhaust nozzle. This provides fuel for the proton exchange membrane fuel cell while simultaneously cooling the inlet air of the high-pressure compressor and preheating the jet fuel. This integrated structure avoids thrust loss caused by extracting electricity from the engine main shaft, significantly improving the engine's power generation capacity and overall energy utilization efficiency. While meeting the increasing power demands of airborne equipment, it effectively reduces the system's carbon emissions.

[0011] Preferably, in the aforementioned hybrid turbofan engine with a combined fuel cell power generation system for liquid ammonia and jet fuel, the power output terminal of the proton exchange membrane fuel cell is connected to the power supply line of the engine's onboard electrical equipment. The proton exchange membrane fuel cell provides electrical energy to the engine's electrical equipment, preventing the equipment from drawing shaft power from the high-pressure turbine and the low-pressure turbine, thereby increasing the output power of the system's core engine.

[0012] Preferably, in the aforementioned hybrid turbofan engine with a combined fuel cell power generation system and liquid ammonia and aviation kerosene, the liquid ammonia preheater is a partitioned heat exchanger, with liquid ammonia flowing through its cold side channel and compressed air from the low-pressure compressor flowing through its hot side channel. The liquid ammonia fuel undergoes phase change and absorbs heat within the preheater, reducing the temperature of the air entering the high-pressure compressor, decreasing compressor power consumption, and increasing the thrust of the engine system.

[0013] Preferably, in the above-mentioned hybrid turbofan engine with liquid ammonia and aviation kerosene for combined fuel cell power generation, the ammonia decomposition hydrogen generator is an indirect heat exchanger, and the ammonia decomposition hydrogen generator is an annular cavity structure sleeved on the outer wall of the tail nozzle. This is used to extract residual heat from the tail nozzle wall, improving the energy utilization rate and thermal efficiency of the engine system.

[0014] Preferably, in the above-mentioned liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation, the inner wall surface of the ammonia decomposition hydrogen generator is coated with a catalyst coating to promote the liquid ammonia decomposition reaction.

[0015] Preferably, in the above-mentioned hybrid turbofan engine with liquid ammonia and jet fuel for combined fuel cell power generation, the catalyst coating is a ruthenium-based catalyst.

[0016] Inside the ammonia decomposition hydrogen generator, ammonia undergoes a decomposition reaction after being catalyzed by the catalyst on the inner wall and heated by the tail nozzle wall, producing hydrogen and nitrogen.

[0017] Preferably, in the above-mentioned dual-fuel hybrid turbofan engine for combined fuel cell power generation using liquid ammonia and jet fuel, the jet fuel preheater is a partitioned heat exchanger. Its hot-side channel is connected to the outlet of the ammonia decomposition hydrogen generator to introduce ammonia decomposition mixed gas, and its cold-side channel is connected to the outlet of the jet fuel pump to introduce jet fuel. The high-temperature ammonia decomposition mixed gas in the jet fuel preheater exchanges heat with the jet fuel, reducing the temperature of the ammonia decomposition mixed gas and increasing the jet fuel temperature at the combustion chamber inlet, thereby improving combustion efficiency.

[0018] Preferably, in the above-mentioned hybrid turbofan engine with liquid ammonia and jet fuel for power generation using a combined fuel cell, the proton exchange membrane fuel cell is a cryogenic proton exchange membrane fuel cell or a high-temperature proton exchange membrane fuel cell. Its anode working fluid is hydrogen, its cathode working fluid is air, its outlet gas is water vapor and unreacted air, and its exhaust gas is discharged directly into the atmosphere from the proton exchange membrane fuel cell.

[0019] Preferably, in the above-mentioned dual-fuel hybrid turbofan engine combining ammonia and jet fuel for power generation, the motors of the ammonia fuel pump and the jet fuel pump are electrically connected to the power output terminal of the proton exchange membrane fuel cell. The power requirements of the ammonia fuel pump and the jet fuel pump are supplied by the proton exchange membrane fuel cell to maintain the normal operation of the pumps.

[0020] Preferably, in the aforementioned hybrid turbofan engine for combined fuel cell power generation using liquid ammonia and jet fuel, the fan outlet is connected to both the outer bypass duct and the inner bypass duct. The entire system is arranged within the inner bypass duct.

[0021] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation, which has the following beneficial effects: 1. This invention combines a traditional turbine power system with a fuel cell power system and applies it to a turbofan engine. This significantly improves the power generation capacity of the turbofan engine, meeting the increasing power demands of onboard electrical equipment and reducing the carbon emissions of the turbofan engine. Simultaneously, it avoids onboard equipment extracting electrical power from the engine's main shaft, reducing engine thrust loss and simplifying the structure of the power generation system.

[0022] 2. This invention utilizes liquid ammonia fuel to cool the inlet air of the high-pressure compressor, reducing compressor power consumption and increasing the output power of the engine system. Compared to traditional air intercooling methods, this invention can improve the heat transfer efficiency and convective heat transfer coefficient of the intercooler, reduce the weight of the intercooler, reduce the pressure loss of the bypass gas, and improve the thrust performance of the bypass gas.

[0023] 3. This invention utilizes ammonia fuel to extract waste heat from the exhaust nozzle wall, improving the engine's energy utilization rate. Compared to traditional regeneration methods, this invention avoids pressure loss during exhaust from the exhaust nozzle, improves the thrust performance of the internal combustion gases, and has significant implications for promoting the development of future advanced turboshaft engine designs. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 The attached figure is a structural schematic diagram of the liquid ammonia and jet fuel dual-fuel hybrid turbofan engine for combined fuel cell power generation provided by the present invention.

[0026] in: 1 is the air intake; 2 is the fan; 3 is the low-pressure compressor; 4 is the high-pressure compressor; 5 is the combustion chamber; 6 is the high-pressure turbine; 7 is the low-pressure turbine; 8 is the tail nozzle; 9 is the liquid ammonia storage tank; 10 is the liquid ammonia fuel pump; 11 is the liquid ammonia preheater; 12 is the ammonia decomposition hydrogen generator; 13 is the aviation kerosene storage tank; 14 is the aviation kerosene fuel pump; 15 is the aviation kerosene preheater; 16 is the proton exchange membrane fuel cell; 17 is the pressure reducing valve. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] See appendix Figure 1 This invention discloses a liquid ammonia and aviation kerosene dual-fuel hybrid turbofan engine that combines fuel cell power generation, comprising: an intake duct 1 and a fan 2 connected sequentially along the airflow direction, with the outlet of the fan 2 connected to an outer bypass duct and an inner bypass duct respectively; within the inner bypass duct, the fan 2 is sequentially connected to a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, a low-pressure turbine 7, and an exhaust nozzle 8; it also includes a liquid ammonia fuel subsystem, an aviation kerosene fuel subsystem, and a fuel cell power supply system; The liquid ammonia fuel subsystem includes a liquid ammonia storage tank 9, a liquid ammonia fuel pump 10, a cold side channel of a liquid ammonia preheater 11, and an ammonia decomposition hydrogen generator 12, which are connected in sequence by pipelines. The aviation kerosene fuel subsystem includes a cold-side passage of an aviation kerosene storage tank 13, an aviation kerosene fuel pump 14, and an aviation kerosene preheater 15 connected in sequence by pipelines. The outlet of the cold-side passage of the aviation kerosene preheater 15 is connected to the fuel inlet of the combustion chamber 5. The fuel cell power supply system includes a proton exchange membrane fuel cell 16 and a pressure reducing valve 17; Wherein: the outlet of the low-pressure compressor 3 is connected to the inlet of the hot side channel of the liquid ammonia preheater 11, and the outlet of the hot side channel of the liquid ammonia preheater 11 is divided into two paths: one path is connected to the inlet of the high-pressure compressor 4, and the other path is connected to the cathode inlet of the proton exchange membrane fuel cell 16 via the pressure reducing valve 17. The outlet of the ammonia decomposition hydrogen generator 12 is connected to the inlet of the hot side channel of the jet fuel preheater 15, and the outlet of the hot side channel of the jet fuel preheater 15 is connected to the anode inlet of the proton exchange membrane fuel cell 16.

[0029] To further optimize the above technical solution, the power output terminal of the proton exchange membrane fuel cell 16 is connected to the power supply line of the engine's onboard electrical equipment.

[0030] To further optimize the above technical solution, the liquid ammonia preheater 11 is a partitioned heat exchanger, in which liquid ammonia flows in the cold side channel and compressed air from the low-pressure compressor 3 flows in the hot side channel.

[0031] To further optimize the above technical solution, the ammonia decomposition hydrogen generator 12 is an indirect heat exchanger, and the ammonia decomposition hydrogen generator 12 is an annular cavity structure sleeved on the outer wall of the tail nozzle 8.

[0032] To further optimize the above technical solution, the inner wall of the ammonia decomposition hydrogen generator 12 is coated with a catalyst coating.

[0033] To further optimize the above technical solution, the catalyst coating is a ruthenium-based catalyst. In this embodiment, K-Ru / CNFs or K-Ru / γ-Al2O3 are selected.

[0034] To further optimize the above technical solution, the jet fuel preheater 15 is a partitioned heat exchanger. Its hot side channel is connected to the outlet of the ammonia decomposition hydrogen generator 12 to introduce ammonia decomposition mixed gas, and its cold side channel is connected to the outlet of the jet fuel pump 14 to introduce jet fuel.

[0035] To further optimize the above technical solution, the proton exchange membrane fuel cell 16 is a low-temperature proton exchange membrane fuel cell or a high-temperature proton exchange membrane fuel cell.

[0036] To further optimize the above technical solution, the motors of the liquid ammonia fuel pump 10 and the jet fuel pump 14 are electrically connected to the power output terminal of the proton exchange membrane fuel cell 16.

[0037] To further optimize the above technical solution, the outlet of fan 2 is connected to both the outer duct channel and the inner duct channel.

[0038] The working process of the liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation provided in this embodiment is as follows: Outside the engine, incoming air from a distance enters the intake duct 1, where it is decelerated and diffused to form a uniform airflow. This air then enters the fan 2 for initial pressurization. At the fan 2 outlet, the air splits into two streams, flowing into the outer bypass duct and the inner bypass duct respectively. In the outer bypass duct, the air is accelerated by the duct wall and ejected, providing thrust to the engine. In the inner bypass duct, the air undergoes secondary pressurization by the low-pressure compressor 4 before entering the liquid ammonia preheater 11. There, it exchanges heat with liquid ammonia drawn from the liquid ammonia storage tank 9 by the liquid ammonia fuel pump 10. After heat exchange, the liquid ammonia vaporizes into ammonia gas, causing the air temperature to drop. The air then splits again, entering the high-pressure compressor 4 and the pressure reducing valve 17. After pressure reduction by the pressure reducing valve 17, the air pressure decreases and is then introduced into the cathode of the proton exchange membrane fuel cell 16. After being pressurized by the high-pressure compressor 4, the air enters the combustion chamber 5, where it mixes thoroughly with the preheated aviation kerosene and burns to form high-temperature, high-pressure gas. This gas then drives the high-pressure turbine 6 and the low-pressure turbine 7, providing power to the fan 2, the low-pressure compressor 3, and the high-pressure compressor 4. Afterward, the gas enters the tail nozzle 8, is accelerated by the tail nozzle, and is then ejected from the inner duct to power the aircraft.

[0039] The ammonia gas, vaporized in the liquid ammonia preheater 11, is introduced into the ammonia decomposition hydrogen generator 12. After being heated by the high-temperature tail nozzle wall and the action of the ruthenium-based catalyst, it decomposes to produce hydrogen and nitrogen. Then, it enters the aviation kerosene preheater 15 to heat the low-temperature aviation kerosene, thereby lowering the temperature of the ammonia decomposition mixture. It is then introduced into the anode of the proton exchange membrane fuel cell 16, where it reacts with the air at the cathode to produce water, which is then discharged from the engine. The generated electricity supplies the operation of various airborne electrical equipment and maintains the normal operation of the liquid ammonia fuel pump 10 and the aviation kerosene fuel pump 14.

[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-fuel hybrid turbofan engine combining a liquid ammonia and jet fuel for power generation, comprising: The air intake (1), fan (2), low-pressure compressor (3), high-pressure compressor (4), combustion chamber (5), high-pressure turbine (6), low-pressure turbine (7) and tail nozzle (8) are connected sequentially along the airflow direction; characterized in that it also includes a liquid ammonia fuel subsystem, a jet fuel subsystem and a fuel cell power supply system; The liquid ammonia fuel subsystem includes a liquid ammonia storage tank (9), a liquid ammonia fuel pump (10), a cold side channel of a liquid ammonia preheater (11), and an ammonia decomposition hydrogen generator (12) connected in sequence by pipelines. The aviation fuel subsystem includes a cold-side passage of an aviation fuel storage tank (13), an aviation fuel pump (14), and an aviation fuel preheater (15) connected in sequence by pipelines. The outlet of the cold-side passage of the aviation fuel preheater (15) is connected to the fuel inlet of the combustion chamber (5). The fuel cell power supply system includes a proton exchange membrane fuel cell (16) and a pressure reducing valve (17). Wherein: the outlet of the low-pressure compressor (3) is connected to the hot-side channel inlet of the liquid ammonia preheater (11), and the hot-side channel outlet of the liquid ammonia preheater (11) is divided into two paths: one path is connected to the inlet of the high-pressure compressor (4), and the other path is connected to the cathode inlet of the proton exchange membrane fuel cell (16) via the pressure reducing valve (17). The outlet of the ammonia decomposition hydrogen generator (12) is connected to the hot-side channel inlet of the jet fuel preheater (15), and the hot-side channel outlet of the jet fuel preheater (15) is connected to the anode inlet of the proton exchange membrane fuel cell (16).

2. The liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 1, characterized in that, The power output terminal of the proton exchange membrane fuel cell (16) is connected to the power supply line of the engine's onboard electrical equipment.

3. The liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 1, characterized in that, The liquid ammonia preheater (11) is a partitioned heat exchanger, in which liquid ammonia flows through the cold side channel and compressed air from the low-pressure compressor (3) flows through the hot side channel.

4. The liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 1, characterized in that, The ammonia decomposition hydrogen generator (12) is an indirect heat exchanger, and the ammonia decomposition hydrogen generator (12) is an annular cavity structure sleeved on the outer wall of the tail nozzle (8).

5. A liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 4, characterized in that, The inner wall of the ammonia decomposition hydrogen generator (12) is coated with a catalyst coating.

6. A liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 5, characterized in that, The catalyst coating is a ruthenium-based catalyst.

7. A liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 1, characterized in that, The jet fuel preheater (15) is a partitioned heat exchanger. Its hot side channel is connected to the outlet of the ammonia decomposition hydrogen generator (12) to introduce ammonia decomposition mixed gas, and its cold side channel is connected to the outlet of the jet fuel pump (14) to introduce jet fuel.

8. The liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 1, characterized in that, The proton exchange membrane fuel cell (16) is a low-temperature proton exchange membrane fuel cell or a high-temperature proton exchange membrane fuel cell.

9. A liquid ammonia-jet dual-fuel hybrid turbofan engine for combined fuel cell power generation according to claim 1, characterized in that, The motors of the liquid ammonia fuel pump (10) and the aviation kerosene fuel pump (14) are electrically connected to the power output terminal of the proton exchange membrane fuel cell (16).

10. A dual-fuel hybrid turbofan engine for liquid ammonia and aviation kerosene combined with fuel cell power generation according to claim 1, characterized in that, The outlet of the fan (2) is connected to the outer duct channel and the inner duct channel, respectively.

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