A compact high temperature fuel cell jet engine multi-modal split hybrid propulsion system

Abstract

The application provides a compact high-temperature fuel cell jet engine multi-mode split hybrid propulsion system, which is beneficial to solve the problems of low thermal efficiency, high fuel consumption and high nitrogen oxide emission of traditional aviation gas turbine engines. The system comprises a propulsion system, a transmission system and a lubrication system; the propulsion system adopts parallel double shafts; the two connecting shafts can transmit power through the transmission system to realize two working modes of the ducted fan; the lubrication system sends lubricating oil to all shafts on the shaft. The high-temperature solid oxide fuel cell system is used to supply power to the motor through the direct current conversion device, and then the motor drives the ducted fan, so that the total efficiency and total thrust of the hybrid propulsion system are improved. The hydrogen-rich combustion chamber and the hydrogen-lean combustion chamber are added to the structure, so that the problem of fuel preheating of the high-temperature solid oxide fuel cell through the heat exchanger with complex pipelines is solved.

Description

Technical Field

[0001] This invention belongs to the field of aircraft propulsion system technology, and more specifically, relates to a compact high-temperature fuel cell jet engine multimodal split hybrid propulsion system. Background Technology

[0002] Traditional aero gas turbine engines convert the chemical energy of fuel into mechanical energy to generate propulsion work. However, they suffer from low thermal efficiency, high fuel consumption, and high nitrogen oxide emissions, resulting in significant environmental pollution. This problem urgently needs to be addressed.

[0003] Solid oxide fuel cells (SOFCs) are fuel cells that use solid oxides as electrolytes and operate at high temperatures. They are a highly efficient and clean energy conversion technology with broad application prospects. They can directly and efficiently convert the chemical energy stored in fuel and oxidant into electrical energy in an environmentally friendly manner, avoiding the energy losses during chemical reactions and energy conversion processes in traditional batteries. Because the entire power generation process is an electrochemical reaction without the need for fuel combustion, it is not limited by the Carnot cycle, and theoretically, the conversion efficiency can reach over 85%–90%.

[0004] Solid oxide fuel cells (SOFCs) are all-solid-state structures, eliminating the corrosion and electrolyte loss problems associated with liquid electrolytes, thus enabling long-term operation. Operating at 800–1000°C, they not only eliminate the need for precious metals in their electrocatalysts but also allow the direct use of natural gas, coal gas, and hydrocarbons as fuel, simplifying the fuel cell system. They also offer advantages such as high power density, simple equipment, and low noise, and produce virtually no harmful substances like nitrogen oxides and sulfides during operation, making them environmentally friendly. Due to their high operating temperature, based on the principle of temperature-matched energy cascade utilization, they can be combined with gas turbines to form more thermally efficient SOFC / GT hybrid power systems. Therefore, hybrid propulsion systems integrated with solid oxide fuel cells help improve the energy efficiency of aerospace power systems and reduce pollutant emissions. Summary of the Invention

[0005] To address the problems of low thermal efficiency, high fuel consumption, and high nitrogen oxide emissions in traditional aero gas turbine engines, this invention proposes a compact high-temperature fuel cell jet engine multimodal split hybrid propulsion system.

[0006] The technical solution provided by this invention is as follows: a compact high-temperature fuel cell jet engine multimodal split hybrid propulsion system, comprising a propulsion system, a transmission system and a lubrication system.

[0007] The propulsion system employs a parallel dual-shaft configuration, with connecting shaft I and connecting shaft II running parallel to each other. From front to back, connecting shaft I comprises: an air intake, a low-pressure compressor, a high-pressure compressor, a lean-hydrogen combustion chamber and a rich-hydrogen combustion chamber, a high-temperature solid oxide fuel cell system, a combustion chamber, a high-pressure turbine, a low-pressure turbine, and an exhaust nozzle. The low-pressure compressor is connected to the low-pressure turbine via connecting shaft I; the high-pressure compressor is connected to the high-pressure turbine via connecting shaft I; the ducted fan is connected to the motor shaft of the electric motor via connecting shaft II; and the high-temperature solid oxide fuel cell system is connected to the electric motor via a DC-DC converter to power the motor.

[0008] The transmission system includes a drive shaft and a clutch. The lubrication system includes a lubricating oil delivery passage and a lubricating oil delivery pump.

[0009] The compressed airflow from the high-pressure compressor is divided into three streams: one stream flows into the lean hydrogen combustion chamber through the inlet channel; another stream flows into the hydrogen-rich combustion chamber through the inlet channel; and the final stream flows into the combustion chamber through an air channel. The intake air volume can be controlled by a valve. The outlet airflow from the lean hydrogen combustion chamber flows into the cathode of the high-temperature solid oxide fuel cell system through the outlet channel; the outlet airflow from the hydrogen-rich combustion chamber flows into the anode of the high-temperature solid oxide fuel cell system through the outlet channel; the outlet airflow from the anode of the high-temperature solid oxide fuel cell system flows into the combustion chamber through the outlet channel; and the outlet airflow from the cathode flows into the combustion chamber through the outlet channel.

[0010] There are multiple drive shafts, each with bevel gears installed at both ends; there are also multiple clutches, each mounted on a drive shaft in a one-to-one configuration; when none of the clutches are working or partially working, connecting shaft I transmits power to connecting shaft II through the meshing of the bevel gears at both ends of the drive shaft; when all the clutches are working, no power is transmitted; thus, the ducted fan has two operating modes: one is driven only by the electric motor, and the other is driven by both the electric motor and the power transmitted from connecting shaft I.

[0011] Preferably, in the hydrogen-rich combustion chamber, excess hydrogen is introduced and ignited with the incoming air, and the resulting gas flow flows into the anode of the high-temperature solid oxide fuel cell system; in the hydrogen-lean combustion chamber, the introduced air is ignited with a small amount of hydrogen, and the resulting gas flow flows into the cathode of the high-temperature solid oxide fuel cell system, thereby eliminating the fuel preheating step required for the high-temperature fuel cell.

[0012] Preferably, the high-temperature solid oxide fuel cell system is composed of three cylindrical fuel cell stacks; the three cylindrical fuel cell stacks are arranged sequentially on the connecting shaft I; gas from the hydrogen-lean combustion chamber is introduced into the cathode of each cylindrical fuel cell stack, while gas from the hydrogen-rich combustion chamber is introduced into the anode, thereby causing an electrochemical reaction inside the high-temperature solid oxide fuel cell system to generate direct current.

[0013] Preferably, there are multiple motors arranged in a coupled structure on the connecting shaft II; the stator of the motor directly exchanges heat with the compressed air of the ducted fan to achieve heat dissipation of the motor.

[0014] Preferably, there are two lubricating oil delivery pumps, both of which are located between connecting shaft I and connecting shaft II; the two lubricating oil delivery pumps are connected through the lubricating oil delivery passage to form a circulation loop, delivering lubricating oil to all shaft systems on the shaft.

[0015] The beneficial effects of this invention are:

[0016] (1) Compared with traditional aero gas turbine engines, this invention adds a hydrogen-rich combustion chamber, a hydrogen-lean combustion chamber, and a high-temperature solid oxide fuel cell system to its structure. This invention utilizes the hydrogen-rich and hydrogen-lean combustion chambers to solve the problem of requiring a heat exchanger with complex piping for fuel preheating in high-temperature solid oxide fuel cells. This invention uses the DC electric current generated by the high-temperature solid oxide fuel cell to drive an electric motor, which in turn drives a ducted fan to generate thrust, thus improving the overall efficiency and total thrust of the hybrid propulsion system.

[0017] (2) The present invention utilizes a clutch to realize two working modes of the ducted fan, and the entire hybrid propulsion system also has two working states, which can better adapt to changes in the flight state of the aircraft and meet the power requirements of the aircraft.

[0018] (3) This invention utilizes the advantages of high thermal efficiency and almost no polluting gas emissions of high-temperature solid oxide fuel cells to solve the problems of low thermal efficiency and high nitrogen oxide emissions of traditional aviation gas turbine engines. Attached Figure Description

[0019] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the hybrid propulsion system integrated with the high-temperature solid oxide fuel cell described in this invention.

[0021] In the diagram: 1-Connecting shaft; 2-Inlet duct; 3-Low-pressure compressor; 4-High-pressure compressor; 5-Lean hydrogen combustion chamber inlet duct; 6-Valve; 7-Hydrogen-rich combustion chamber inlet duct; 8-Lean hydrogen combustion chamber; 9-Hydrogen-rich combustion chamber; 10-Lean hydrogen combustion chamber outlet duct; 11-Hydrogen-rich combustion chamber outlet duct; 12-Air duct; 13-Cathode outlet duct; 14-Anode outlet duct; 15-Cylindrical fuel cell stack; 16-DC converter; 17-Combustion chamber; 18-High-pressure turbine; 19-Low-pressure turbine; 20-Tail nozzle; 21-Connecting shaft; 22-Electric motor; 23-Clutch; 24-Bevel gear; 25-Ducted fan; 26-Drive shaft; 27-Lubricating oil delivery pump. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0024] See Figure 1 This embodiment describes a compact high-temperature fuel cell jet engine multimodal split hybrid propulsion system, which includes a propulsion system, a transmission system, and a lubrication system.

[0025] The propulsion system is a combination of a high-temperature solid oxide fuel cell and an aero gas turbine engine.

[0026] The propulsion system adopts a parallel dual-shaft configuration, with connecting shaft I1 and connecting shaft II21 being parallel to each other. From front to back, the connecting shaft I1 consists of: an air intake 2, a low-pressure compressor 3, a high-pressure compressor 4, a hydrogen-lean combustion chamber 8 and a hydrogen-rich combustion chamber 9, a high-temperature solid oxide fuel cell system, a combustion chamber 17, a high-pressure turbine 18, a low-pressure turbine 19, and an exhaust nozzle 20. The low-pressure compressor 3 is connected to the low-pressure turbine 19 via connecting shaft I1, and the high-pressure compressor 4 is connected to the high-pressure turbine 18 via connecting shaft I1.

[0027] The ducted fan 25 is connected to the motor shafts of multiple motors 22 via connecting shaft II 21; the high-temperature solid oxide fuel cell system is connected to the multiple motors 22 via DC-DC converter 16 to power the multiple motors 22; the multiple motors 22 are arranged in a coupled structure on connecting shaft II 21; the stators of the motors 22 directly exchange heat with the air compressed by the ducted fan 25 to achieve heat dissipation of the motors 22.

[0028] The transmission system includes drive shafts 26 and clutches 23. There are multiple drive shafts 26, each with bevel gears 24 mounted at both ends; there are also multiple clutches 23, each mounted on a drive shaft 26 in a one-to-one configuration. When none of the clutches 23 are working or partially working, connecting shaft I1 transmits power to connecting shaft II 21 through the meshing of the bevel gears 24 at both ends of the drive shaft 26; when all clutches 23 are working, no power is transmitted. Thus, the ducted fan 25 has two operating modes: one where it is driven only by the electric motor 22, and the other where it is driven by both the electric motor 22 and the power transmitted from connecting shaft I1.

[0029] The lubrication system includes a lubricating oil delivery passage and a lubricating oil delivery pump. There are two lubricating oil delivery pumps 27, both of which are located between connecting shaft I and connecting shaft II; the two lubricating oil delivery pumps 27 are connected through the lubricating oil delivery passage to form a circulation loop, delivering lubricating oil to all shafts on the shaft.

[0030] The airflow compressed by the high-pressure compressor 4 is divided into three streams: one stream flows through the inlet channel 5 of the lean hydrogen combustion chamber to the lean hydrogen combustion chamber 8; another stream flows through the inlet channel 7 of the hydrogen-rich combustion chamber to the hydrogen-rich combustion chamber 9; and the last stream flows through the air channel 12 to the combustion chamber 17. The intake air volume can be controlled by the valve 6. The airflow from the outlet of the lean hydrogen combustion chamber 8 flows through the outlet channel 10 to the cathode of the high-temperature solid oxide fuel cell system; the airflow from the outlet of the hydrogen-rich combustion chamber 9 flows through the outlet channel 11 to the anode of the high-temperature solid oxide fuel cell system; the airflow from the anode outlet of the high-temperature solid oxide fuel cell system flows through the anode outlet channel 13 to the combustion chamber 17, and the airflow from the cathode outlet flows through the cathode outlet channel 14 to the combustion chamber 17.

[0031] The hydrogen-rich combustion chamber 9 is introduced with excess hydrogen, which is ignited and burned with the incoming air. The resulting gas flow flows into the anode of the high-temperature solid oxide fuel cell system. In the hydrogen-lean combustion chamber 8, the introduced air is ignited and burned with a small amount of hydrogen. The resulting gas flow flows into the cathode of the high-temperature solid oxide fuel cell system, thereby eliminating the need for the fuel preheating step required for the high-temperature fuel cell.

[0032] The high-temperature solid oxide fuel cell system is composed of three cylindrical fuel cell stacks 15. The three cylindrical fuel cell stacks 15 are arranged sequentially on the connecting shaft I1. Gas from the hydrogen-lean combustion chamber 8 is introduced into the cathode of each cylindrical fuel cell stack 15, while gas from the hydrogen-rich combustion chamber 9 is introduced into the anode. As a result, an electrochemical reaction occurs inside the high-temperature solid oxide fuel cell system, generating direct current.

[0033] The working principle of the compact high-temperature fuel cell jet engine multimodal split hybrid propulsion system described in this invention is as follows:

[0034] This invention does not use traditional fuel oil, but instead uses hydrogen as fuel. Structurally, it adds a hydrogen-rich combustion chamber, a hydrogen-lean combustion chamber, and a high-temperature solid oxide fuel cell system. This invention utilizes the combustion products from the hydrogen-rich and hydrogen-lean combustion chambers, which are fed into the high-temperature solid oxide fuel cell system to undergo an electrochemical reaction, generating electricity. This electricity then drives an electric motor, which in turn powers a ducted fan to generate thrust. Simultaneously, the exhaust gas from the high-temperature solid oxide fuel cell system and a portion of unburned air are directly fed into the combustion chamber for ignition and combustion. The exhaust nozzle then accelerates the exhaust gas, generating thrust, thus achieving full utilization of hydrogen energy. This invention allows for two operating modes of the ducted fan by controlling the clutch in the transmission system, and the entire hybrid propulsion system also has two operating states, better adapting to changes in aircraft flight conditions and meeting the aircraft's power requirements. The use of a high-temperature solid oxide fuel cell in this invention improves thermal efficiency and achieves zero-pollution gas emissions.

[0035] The working process of the compact high-temperature fuel cell jet engine multimodal split hybrid propulsion system described in this invention is as follows:

[0036] Air from the atmosphere first passes through the intake duct, then enters the low-pressure compressor and the high-pressure compressor, where it is compressed and divided into three parts: one part enters the hydrogen-rich combustion chamber and burns excess hydrogen before being fed into the anode channel of the high-temperature solid oxide fuel cell system; another part enters the hydrogen-lean combustion chamber and burns a small amount of hydrogen before being fed into the cathode channel of the high-temperature solid oxide fuel cell system; at this point, the high-temperature solid oxide fuel cell system uses hydrogen as the anode reactant and air as the cathode reactant to undergo an electrochemical reaction, achieving electron transfer and generating direct current (DC); the DC voltage is then adjusted by a DC-DC converter and sent to the electric motor, which drives the ducted fan; the ducted fan ejects compressed air backward, and the airflow generates a reaction force, thus generating thrust; the remaining air and exhaust gas from the high-temperature solid oxide fuel cell system are fed into the combustion chamber and ignited with hydrogen, and the resulting high-temperature gas is expanded and does work after passing through the low-pressure turbine and the high-pressure turbine, and is then accelerated and discharged through the tail nozzle, where the airflow generates a reaction force that propels the aircraft forward.

[0037] 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 compact high temperature fuel cell jet engine multi-modal split-body hybrid propulsion system characterized by: The propulsion system, the transmission system and the lubrication system are included. The propulsion system adopts parallel double shafts, i.e. the connecting shaft I (1) and the connecting shaft II (21) are parallel to each other; the connecting shaft I (1) is sequentially provided with an air inlet channel (2), a low-pressure compressor (3), a high-pressure compressor (4), a lean hydrogen combustion chamber (8) and a rich hydrogen combustion chamber (9), a high-temperature solid oxide fuel cell system, a combustion chamber (17), a high-pressure turbine (18), a low-pressure turbine (19) and a tail nozzle (20) from front to back; the low-pressure compressor (3) is connected with the low-pressure turbine (19) through the connecting shaft I (1); the high-pressure compressor (4) is connected with the high-pressure turbine (18) through the connecting shaft I (1); a ducted fan (25) is connected with a motor shaft of an electric motor (22) through the connecting shaft II (21); the high-temperature solid oxide fuel cell system is connected with the electric motor (22) through a direct current conversion device (16) to supply power for the electric motor (22); The transmission system includes a transmission shaft (26) and a clutch (23); the lubrication system includes a lubricating oil conveying passage and a lubricating oil delivery pump; the transmission shaft (26) is provided with a bevel gear (24) at both ends; the clutch (23) is also provided with a plurality of clutches, which are one-to-one installed on the transmission shaft (26); when the clutches (23) are not working or partially not working, the connecting shaft I (1) transmits power to the connecting shaft II (21) through the meshing of the bevel gears (24) at both ends of the transmission shaft (26); when the clutches (23) are all working, no power is transmitted; in this way, the ducted fan (25) has two working modes: one is driven by the electric motor (22) only, and the other is driven by the electric motor (22) and the power transmitted by the connecting shaft I (1); The airflow compressed by the high-pressure compressor (4) is divided into three paths, one of which flows to the lean hydrogen combustion chamber (8) through the lean hydrogen combustion chamber inlet flow channel (5); one of which flows to the rich hydrogen combustion chamber (9) through the rich hydrogen combustion chamber inlet flow channel (7); the last one of which flows to the combustion chamber (17) through the air flow channel (12), and the air intake amount can be controlled by the valve (6); the lean hydrogen combustion chamber (8) outlet airflow flows to the cathode of the high-temperature solid oxide fuel cell system through the lean hydrogen combustion chamber outlet flow channel (10); the rich hydrogen combustion chamber (9) outlet airflow flows to the anode of the high-temperature solid oxide fuel cell system through the rich hydrogen combustion chamber outlet flow channel (11); the anode outlet airflow of the high-temperature solid oxide fuel cell system flows to the combustion chamber (17) through the anode outlet flow channel (13), and the cathode outlet airflow flows to the combustion chamber (17) through the cathode outlet flow channel (14).

2. The compact high temperature fuel cell jet engine multi-modal split-body hybrid propulsion system of claim 1, wherein: The rich hydrogen combustion chamber (9) is supplied with excess hydrogen, which is ignited and burned with the inflowing air, and the burned airflow flows into the anode of the high-temperature solid oxide fuel cell system; in the lean hydrogen combustion chamber (8), the inflowing air is ignited and burned with a small amount of hydrogen, and the burned airflow flows into the cathode of the high-temperature solid oxide fuel cell system, thereby omitting the fuel preheating step required by the high-temperature fuel cell.

3. The compact high temperature fuel cell jet engine multi-modal split-body hybrid propulsion system of claim 1, wherein: The high-temperature solid oxide fuel cell system is composed of three cylindrical fuel cell stacks (15); the three cylindrical fuel cell stacks (15) are arranged in sequence on the connecting shaft I (1); the cathode of each cylindrical fuel cell stack (15) is connected to the gas from the hydrogen-poor combustion chamber (8), while the anode is connected to the gas from the hydrogen-rich combustion chamber (9), so that an electrochemical reaction occurs inside the high-temperature solid oxide fuel cell system to generate direct current.

4. The compact high temperature fuel cell jet engine multi-modal split-body hybrid propulsion system of claim 1, wherein: The electric motor (22) is in a plurality of coupling structures arranged on the connecting shaft II (21); the stator of the electric motor (22) directly exchanges heat with the compressed air of the ducted fan (25), achieving heat dissipation of the electric motor (22).

5. The compact high temperature fuel cell jet engine multi-modal split-body hybrid propulsion system of claim 1, wherein: The lubricating oil delivery pump (27) is two, both arranged between the connecting shaft I and the connecting shaft II; the two lubricating oil delivery pumps (27) are connected through the lubricating oil conveying passage to form a circulating loop to send lubricating oil to all shafting on the shaft.

Images