Indirect cooling-regenerative power generation system based on liquid hydrogen fuel turbofan engine

Abstract

The invention provides an indirect cooling-regenerative power generation system based on a liquid hydrogen fuel turbofan engine, belongs to the technical field of aviation systems, and aims at solving the problems that in an existing aviation propulsion system, the power utilization requirement is continuously increased, and the energy utilization efficiency is limited. The system comprises an air inlet channel, a fan, a low-pressure compressor, an intercooler, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a heat regenerator, a core exhaust nozzle, an outer culvert nozzle and a helium closed Brayton cycle power generation subsystem coupled with an engine. The power generation subsystem comprises a liquid hydrogen fuel tank, a cooler, a helium compressor, a heat exchanger, a helium turbine and a power generator. Liquid hydrogen cold energy utilization, intermediate cooling, exhaust waste heat recovery and an airborne power generation system are integrated, cooperative operation of propulsion and power generation is achieved, the overall energy utilization efficiency and fuel economy of the engine are effectively improved, and the system is suitable for a low-carbon, efficient and electrified aviation propulsion system.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine and airborne energy system technology, and relates to integrated energy utilization technology that deeply integrates aero-propulsion system and airborne power generation system, and in particular to an intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine. Background Technology

[0002] As aircraft evolve towards higher speeds, longer flight times, and electrification, the demand for electrical energy from airborne systems continues to grow. Traditional aero engines, primarily focused on propulsion, are increasingly showing limitations in meeting the demands of high-power airborne power and improving overall energy efficiency. On one hand, existing turbofan engines, under cruise and high-load conditions, directly emit a large amount of high-grade energy as exhaust heat and jet kinetic energy, without effective recovery and utilization, resulting in low overall system energy efficiency. On the other hand, the high temperatures generated during the engine's internal compression process limit the potential for further reductions in compression work and improvements in cycle efficiency.

[0003] In recent years, liquid hydrogen fuel has been considered an important development direction for future aerospace propulsion systems due to its high specific energy, lack of carbon emissions during combustion, and significant advantages in cold energy and latent heat of phase change during cryogenic storage. Liquid hydrogen absorbs a large amount of latent heat during its transition from liquid to gas, providing unique conditions for engine thermal management and cycle optimization. Theoretically, fully utilizing the cryogenic cold energy and latent heat of phase change of liquid hydrogen can help reduce the internal temperature level of the engine, decrease compression work requirements, and improve cycle efficiency.

[0004] However, in practical engineering applications, due to limitations such as safety, structural reliability, and system integration feasibility, liquid hydrogen is usually difficult to directly exchange heat with the core airflow of an engine. Existing solutions mostly employ intermediate heat exchange media or indirect cooling loops, using multi-stage heat exchangers to transfer the cold energy of liquid hydrogen to the air side. This indirect cooling method, to some extent, limits the effective release of the cold energy of liquid hydrogen and the latent heat of phase change to the core airflow, thus constraining the reduction in air temperature. Relying solely on the cryogenic cold energy of liquid hydrogen is insufficient to significantly reconstruct the energy distribution structure of the engine at the system level.

[0005] Meanwhile, indirect cooling and regenerative heating technologies, as important means to improve the energy utilization efficiency of gas turbines, have been studied in various gas turbine systems. Indirect cooling technology reduces the compression work demand by lowering the airflow temperature during the compression process, while regenerative heating technology preheats the compressed air by recovering waste heat from the turbine exhaust, thereby reducing the amount of fuel required for combustion. Although the above technologies can improve engine performance to some extent, existing solutions mostly focus on a single energy utilization path and have not yet achieved system-level synergistic utilization of liquid hydrogen cold energy, latent heat of phase change, and waste heat from exhaust.

[0006] Furthermore, with the continuous development of avionics systems, flight control systems, and high-power airborne equipment, relying solely on traditional shaft power extraction or external power generation devices is no longer sufficient to meet the demand for efficient and stable power supply. How to convert the high-grade thermal energy in engine exhaust into shaft power or electrical energy without significantly affecting propulsion performance, and combine this with the utilization of liquid hydrogen cold energy and its latent heat of phase change to construct an integrated energy system that coordinates propulsion and power generation, remains a pressing technical problem to be solved in the field of aerospace propulsion.

[0007] Therefore, it is necessary to propose a new aviation propulsion system architecture that deeply integrates liquid hydrogen cold energy and latent heat of phase change, intercooling, regeneration, and airborne power generation systems to improve propulsion performance, fuel economy, and airborne power supply capabilities, thereby meeting the development needs of future low-carbon, high-efficiency, and electrified aviation applications. Summary of the Invention

[0008] In view of this, in order to address the problems of low overall engine energy utilization efficiency, difficulty in recovering high-grade exhaust heat energy, insufficient supply capacity due to increasing airborne power demand, and limited utilization of liquid hydrogen cold energy and latent heat of phase change in existing aviation propulsion systems, this invention proposes an intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine. Through the coordinated design of the propulsion system's gas path, fuel flow path, and power generation system, it achieves synergistic optimization of intercooling enhancement, waste heat recovery, airborne power generation, and propulsion performance improvement, providing a feasible technical solution for a new generation of aviation propulsion systems oriented towards low-carbon and electrification development.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: an intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine, comprising an intake duct, a fan, a low-pressure compressor, an intercooler, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a regenerator, a core exhaust nozzle, an outer bypass nozzle, and a helium closed-loop Brayton cycle power generation system thermally coupled to the engine. The intake duct, fan, low-pressure compressor, high-pressure compressor, combustion chamber, high-pressure turbine, low-pressure turbine, regenerator, and core exhaust nozzle are connected in sequence. An intercooler is provided between the low-pressure compressor and the high-pressure compressor, and the intercooler is connected to the outer bypass nozzle. The helium closed-loop Brayton cycle power generation system includes a liquid hydrogen fuel tank, a cooler, a helium compressor, a heat exchanger, a helium turbine, and a generator. The generator is coaxially connected to the helium turbine and is used to supply power to the onboard load. The generator is coaxially connected to the helium compressor. The cooler is connected to the combustion chamber, the liquid hydrogen fuel tank, the helium turbine, and the helium compressor, respectively. The heat exchanger is connected to the high-pressure compressor, the regenerator, the helium turbine, and the helium compressor, respectively. The regenerator is also connected to the combustion chamber.

[0010] Furthermore, the liquid hydrogen fuel is supplied by a liquid hydrogen fuel tank, and after being cooled by the helium in a cooler as a cryogenic cold source, it enters the combustion chamber to participate in combustion.

[0011] Furthermore, after being compressed in the helium compressor, the helium gas enters the heat exchanger, absorbs the waste heat from the engine exhaust from the regenerator, drives the helium turbine to do work and drives the generator to generate electricity, and then is cooled by the cooler and returned to the helium compressor, forming a closed loop.

[0012] Furthermore, the high-pressure turbine is coaxially connected to the high-pressure compressor and is used to drive the high-pressure compressor to rotate.

[0013] Furthermore, the low-pressure turbine is coaxially connected to the low-pressure compressor and the fan, and the low-pressure turbine simultaneously drives the low-pressure compressor and the fan to rotate.

[0014] Furthermore, the helium-based closed-loop Brayton cycle power generation system uses helium or a mixture of inert gases with helium as the main component as the working medium.

[0015] Furthermore, the core tail nozzle and the outer bypass nozzle adopt Laval nozzles, and the nozzle area ratio is adjusted to adapt to the thrust requirements under different flight conditions.

[0016] The above-mentioned method of using the intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine: When an aircraft is in flight, the incoming air enters the fan through the air intake and is split into core airflow and bypass airflow. The core airflow is compressed by the low-pressure compressor and then enters the intercooler. In the intercooler, it is cooled by the bypass airflow to reduce the temperature of the airflow entering the high-pressure compressor. The core airflow after intercooling enters the high-pressure compressor for further compression to form high-temperature and high-pressure air. The high-temperature, high-pressure air compressed by the high-pressure compressor first enters the heat exchanger of the helium closed Brayton cycle power generation system, where it serves as a heat source to release heat to the working fluid of the helium closed Brayton cycle power generation system. Subsequently, the air enters the regenerator, where it absorbs residual heat from the exhaust gas after the high-pressure turbine and low-pressure turbine have done their work, and then enters the combustion chamber for combustion. The high-temperature gas produced by combustion drives the high-pressure turbine and the low-pressure turbine to do work in sequence. The gas after doing work expands through the core tail nozzle to generate thrust, and the bypass gas is discharged through the bypass nozzle to form bypass thrust. Compared with the prior art, the beneficial effects of the intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine described in this invention are: 1. This invention introduces a helium-filled closed Brayton cycle generator system to convert high-grade thermal energy in engine exhaust into shaft work and electrical work, providing a stable and continuous power supply to the airborne system without significantly affecting propulsion performance.

[0017] 2. This invention uses liquid hydrogen as a cryogenic cold source for a closed Brayton cycle. Its sensible heat and latent heat of phase change are used to reduce the temperature of the working fluid and the compression work requirement in the closed cycle, thereby achieving efficient cascade utilization of fuel cold energy.

[0018] 3. This invention effectively reduces the temperature of the airflow entering the high-pressure compressor by installing an intercooler between the low-pressure compressor and the high-pressure compressor, thereby reducing the compression work requirement and improving the overall cycle efficiency of the engine. 4. This invention improves the usable energy level of the air entering the combustion chamber by having the air compressed by the high-pressure compressor exchange heat sequentially with the closed Brayton cycle working fluid and the engine exhaust in multiple stages, thereby reducing fuel consumption under the same thrust conditions and thus improving the engine's fuel economy.

[0019] 5. This invention achieves a cascade conversion between fuel cold energy, exhaust heat energy, mechanical energy and electrical energy through the coordinated arrangement of liquid hydrogen cold energy utilization, intermediate cooling and exhaust waste heat recovery, which significantly improves the overall energy utilization efficiency of the system.

[0020] 6. This invention uses liquid hydrogen as fuel, has zero-carbon combustion characteristics, and can simultaneously meet the needs of propulsion and airborne power generation, providing a practical and feasible technical path for building a low-carbon, efficient and electrified aviation propulsion system. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This invention relates to an intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine, as described in an embodiment of the present invention. Explanation of reference numerals in the attached diagram: 1-Inlet, 2-Fan, 3-Low-pressure compressor, 4-Intercooler, 5-High-pressure compressor, 6-Combustion chamber, 7-High-pressure turbine, 8-Low-pressure turbine, 9-Regenerator, 10-Core exhaust nozzle, 11-Outer bypass nozzle, 12-Liquid hydrogen fuel tank, 13-Cooler, 14-Helium compressor, 15-Heat exchanger, 16-Helium turbine, 17-Generator. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0023] See Figure 1 This embodiment describes an intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine, comprising an intake duct 1, a fan 2, a low-pressure compressor 3, an intercooler 4, a high-pressure compressor 5, a combustion chamber 6, a high-pressure turbine 7, a low-pressure turbine 8, a regenerator 9, a core exhaust nozzle 10, an outer bypass nozzle 11, and a helium closed-loop Brayton cycle power generation system thermally coupled to the engine. The intake duct 1, fan 2, low-pressure compressor 3, high-pressure compressor 5, combustion chamber 6, high-pressure turbine 7, low-pressure turbine 8, regenerator 9, and core exhaust nozzle 10 are connected sequentially. An intercooler 4 is provided between the low-pressure compressor 3 and the high-pressure compressor 5, and the intercooler 4 is connected to the outer bypass nozzle 11.

[0024] The helium closed-loop Brayton cycle power generation system includes a liquid hydrogen fuel tank 12, a cooler 13, a helium compressor 14, a heat exchanger 15, a helium turbine 16, and a generator 17. The generator 17 is coaxially connected to the helium turbine 16 and is used to supply power to the onboard load. The generator 17 is coaxially connected to the helium compressor 14. The cooler 13 is connected to the combustion chamber 6, the liquid hydrogen fuel tank 12, the helium turbine 16, and the helium compressor 14, respectively. The heat exchanger 15 is connected to the high-pressure compressor 5, the regenerator 9, the helium turbine 16, and the helium compressor 14, respectively. The regenerator 9 is also connected to the combustion chamber 6.

[0025] In this embodiment, liquid hydrogen fuel is supplied by liquid hydrogen fuel tank 12 and enters cooler 13. Within cooler 13, the liquid hydrogen serves as a cryogenic cold source for the closed Brayton cycle, exchanging heat with helium in the closed Brayton cycle. The helium is cooled through sensible heat absorption and at least part of the latent heat of phase change, thereby reducing the compression work requirement of the closed Brayton cycle. The heat-absorbed hydrogen is then further fed into combustion chamber 6 to participate in combustion, achieving the synergistic utilization of fuel cold energy and chemical energy.

[0026] Before entering the combustion chamber 6, the liquid hydrogen fuel is preferentially used as a cryogenic cold source for the closed Brayton cycle of helium, so as to reduce the compression work of helium in the closed cycle and improve the power generation efficiency.

[0027] In this embodiment, the intercooler 4 is disposed between the low-pressure compressor 3 and the high-pressure compressor 5 to reduce the temperature of the airflow entering the high-pressure compressor, thereby reducing the compression work requirement and improving the thermal matching characteristics of the core machine.

[0028] In this embodiment, the regenerator 9 is located at the outlet of the low-pressure turbine 8 and is used to transfer the high-grade heat energy in the exhaust gas of the core engine to the helium closed Brayton cycle power generation system, so as to realize the conversion of exhaust waste heat into shaft power and electrical power.

[0029] In this embodiment, the high-pressure turbine 7 is coaxially connected to the high-pressure compressor 5 and is used to drive the high-pressure compressor 5 to rotate; the low-pressure turbine 8 is coaxially connected to the low-pressure compressor 3 and the fan 2, and the low-pressure turbine 8 drives the low-pressure compressor 3 and the fan 2 to rotate simultaneously, thereby forming a dual-rotor structure to achieve independent speed matching between the core machine and the fan system.

[0030] In this embodiment, helium serves as the working medium for the closed Brayton cycle. After being compressed in the helium compressor 14, it enters the heat exchanger 15 to absorb heat from the high-pressure compressor outlet air and waste heat from the engine exhaust in the regenerator 9. The heated helium drives the helium turbine 16 to perform work, which in turn drives the generator 17 to generate electricity, which is used to power the onboard load. After performing work, the helium is cooled by the cooler 13 and returned to the helium compressor 14, forming a stable closed cycle.

[0031] The helium-based closed Brayton cycle uses helium or a mixture of inert gases with helium as the main component as the working medium to adapt to high-temperature waste heat recovery conditions and achieve a compact turbomachinery design.

[0032] In this embodiment, the core airflow, after being further compressed by the high-pressure compressor 5, first enters the heat exchanger 15 of the helium closed-loop Brayton cycle generator system, where it releases heat to the working fluid of the helium closed-loop Brayton cycle generator system as a heat source. Then, it enters the regenerator 9, where it absorbs residual heat from the exhaust gas after the high-pressure turbine 7 and low-pressure turbine 8 have performed their work, and then enters the combustion chamber 6 for combustion. Through the above-mentioned multi-stage heat exchange process, the energy level of the air entering the combustion chamber is increased, thereby reducing the amount of fuel required for combustion and improving the engine's fuel economy.

[0033] In this embodiment, the electrical energy generated by the generator 17 is used to supply power to airborne electrical loads, including but not limited to flight control systems, avionics systems, radar systems, and high-power airborne equipment.

[0034] The system can coordinate and adjust the liquid hydrogen fuel flow rate, intercooling intensity, and operating parameters of the helium closed Brayton cycle according to changes in flight altitude, flight Mach number, and onboard power demand, so as to achieve comprehensive optimization of propulsion performance and power generation efficiency.

[0035] In this embodiment, the core tail nozzle 10 and the outer bypass nozzle 11 are Laval nozzles, which can be adjusted by adjusting the nozzle area ratio to adapt to the thrust requirements under different flight conditions and improve the overall efficiency of the propulsion system.

[0036] Through the above structure and working process, this invention achieves the cascade conversion between fuel cold energy, core engine exhaust heat energy, mechanical energy, and electrical energy by synergistically integrating liquid hydrogen cold energy utilization, intercooling, exhaust waste heat recovery, and airborne power generation system. At the same time, it realizes the coordinated operation of propulsion and power generation, significantly improving the overall energy utilization efficiency of the engine and the airborne power supply capability while ensuring propulsion performance. The working process of the intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine described in this invention is as follows: During flight, the incoming airflow enters fan 2 through intake 1 and is split into core airflow and bypass airflow. The core airflow is compressed by low-pressure compressor 3 and then enters intercooler 4, where it is cooled by bypass airflow, thereby reducing the temperature of the airflow entering high-pressure compressor 5. After intercooling, the core airflow enters high-pressure compressor 5 for further compression, forming high-temperature, high-pressure air.

[0037] The high-temperature, high-pressure air compressed by the high-pressure compressor 5 first enters the heat exchanger 15 of the closed Brayton cycle helium gas, where it releases heat to the working fluid of the closed Brayton cycle as a heat source. Then, the air enters the regenerator 9, absorbs residual heat from the exhaust gas after the high-pressure turbine 7 and the low-pressure turbine 8 have done their work, and then enters the combustion chamber 6 for combustion.

[0038] The high-temperature gas generated by combustion drives the high-pressure turbine 7 and the low-pressure turbine 8 to do work in sequence. The gas after doing work expands through the core tail nozzle 10 to generate thrust, and the bypass gas is discharged through the bypass nozzle 11 to form bypass thrust.

[0039] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating orientation and positional relationships are based on the orientation and positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0040] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. An intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine, characterized in that: The engine includes an intake duct (1), a fan (2), a low-pressure compressor (3), an intercooler (4), a high-pressure compressor (5), a combustion chamber (6), a high-pressure turbine (7), a low-pressure turbine (8), a regenerator (9), a core exhaust nozzle (10), and an outer bypass nozzle (11), as well as a helium closed-loop Brayton cycle generator system thermally coupled to the engine. The intake duct (1), fan (2), low-pressure compressor (3), high-pressure compressor (5), combustion chamber (6), high-pressure turbine (7), low-pressure turbine (8), regenerator (9), and core exhaust nozzle (10) are connected in sequence. An intercooler (4) is provided between the low-pressure compressor (3) and the high-pressure compressor (5). The intercooler (4) is connected to the outer bypass nozzle (11). The helium closed Brayton cycle power generation system includes a liquid hydrogen fuel tank (12), a cooler (13), a helium compressor (14), a heat exchanger (15), a helium turbine (16), and a generator (17). The generator (17) is coaxially connected to the helium turbine (16) and is used to supply power to the onboard load. The generator (17) is coaxially connected to the helium compressor (14). The cooler (13) is connected to the combustion chamber (6), the liquid hydrogen fuel tank (12), the helium turbine (16), and the helium compressor (14) respectively. The heat exchanger (15) is connected to the high-pressure compressor (5), the regenerator (9), the helium turbine (16), and the helium compressor (14) respectively. The regenerator (9) is also connected to the combustion chamber (6).

2. The intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine according to claim 1, characterized in that: Liquid hydrogen fuel is supplied by liquid hydrogen fuel tank (12), and after being cooled by helium in cooler (13) as a cryogenic cold source, it enters combustion chamber (6) to participate in combustion.

3. The intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine according to claim 1, characterized in that: After being compressed in the helium compressor (14), the helium gas enters the heat exchanger (15), absorbs the residual heat from the engine exhaust from the regenerator (9), drives the helium turbine (16) to do work and drives the generator (17) to generate electricity, and then is cooled by the cooler (13) and returned to the helium compressor (14), forming a closed loop.

4. The intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine according to claim 1, characterized in that: The high-pressure turbine (7) is coaxially connected to the high-pressure compressor (5) and is used to drive the high-pressure compressor (5) to rotate.

5. The intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine according to claim 4, characterized in that: The low-pressure turbine (8) is coaxially connected to the low-pressure compressor (3) and the fan (2), and the low-pressure turbine (8) drives the low-pressure compressor (3) and the fan (2) to rotate simultaneously.

6. The intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine according to claim 1, characterized in that: The helium-based closed Brayton cycle power generation system uses helium or a mixture of inert gases with helium as the main component as the working medium.

7. The intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine according to claim 1, characterized in that: The core tail nozzle (10) and the outer bypass nozzle (11) adopt Laval nozzles, and the nozzle area ratio is adjusted to meet the thrust requirements under different flight conditions.

8. A method of using an intercooled-regenerative power generation system based on a liquid hydrogen fuel turbofan engine as described in any one of claims 1-7, characterized in that: When the aircraft is in flight, the incoming air enters the fan (2) through the air intake (1) and is split into core airflow and bypass airflow. The core airflow is compressed by the low-pressure compressor (3) and then enters the intercooler (4). In the intercooler (4), it is cooled by the bypass airflow to reduce the temperature of the airflow entering the high-pressure compressor (5). The core airflow after intercooling enters the high-pressure compressor (5) for further compression to form high-temperature and high-pressure air. The high-temperature and high-pressure air compressed by the high-pressure compressor (5) first enters the heat exchanger (15) of the helium closed Brayton cycle power generation system, and releases heat to the working fluid of the helium closed Brayton cycle power generation system as a heat source; then the air enters the regenerator (9), absorbs the residual heat from the exhaust gas after the high-pressure turbine (7) and low-pressure turbine (8) have done work, and then enters the combustion chamber (6) for combustion; The high-temperature gas generated by combustion drives the high-pressure turbine (7) and the low-pressure turbine (8) to do work in sequence. The gas after doing work expands through the core tail nozzle (10) to generate thrust, and the bypass gas is discharged through the bypass nozzle (11) to form bypass thrust.

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