Aero-engine driven by fuel cell

Abstract

The invention belongs to the technical field of aero-engines, and particularly relates to an aero-engine driven by a fuel cell, which comprises a first driving motor, a ducted fan, a first-stage fuel cell stack, a second-stage fuel cell stack and a hydrogen supply system, the first driving motor drives the ducted fan to rotate to generate most airflow which is directly discharged backwards to generate main thrust; a small part of the gas flow firstly enters the first-stage fuel cell stack to provide oxygen for a cathode of the first-stage fuel cell stack and cool the stack, and the gas flow continuously flows into the second-stage fuel cell stack after flowing through the first-stage fuel cell stack to provide oxygen for a cathode of the second-stage fuel cell stack and cool the stack; according to the aero-engine driven by the fuel cell, the structure of the fuel cell and the structure of the aero-engine are subjected to fusion design, and the fuel cell can still be cooled in an air cooling mode under the condition that the total output power of the fuel cell exceeds 5 kW.

Description

Technical Field

[0001] The present invention relates to the technical field of aeroengines, and in particular to an aeroengine driven by a fuel cell. Background Art

[0002] With the environmental problems caused by fossil fuels and the requirements of the "dual carbon strategy", electric propulsion systems have become increasingly important in aviation power due to their advantages of no environmental pollution, high control accuracy, and fast response. Currently, many countries around the world have begun to accelerate the development of aviation electric propulsion systems.

[0003] The existing electric propulsion power system mainly includes thrusters, motors, controllers and batteries. The thrusters can be mainly divided into propellers and ducted fans, the motors are generally permanent magnet synchronous motors, and the batteries are generally high-power density batteries, such as lithium batteries. However, the energy density of batteries in existing electric propulsion power systems is low (<300 Wh / kg), which seriously limits the endurance of the system.

[0004] Compared with batteries, fuel cells have a higher energy density (for example, the energy density of air-cooled hydrogen fuel cells is > 1000 Wh / kg), and are one of the technical solutions to increase the endurance of aviation electric propulsion systems. Taking hydrogen fuel cells as an example, Figure 1 This is the working principle of hydrogen fuel cells. After hydrogen enters the anode, it loses electrons and becomes hydrogen ions. Electrons generate current through the external circuit and flow into the cathode to combine with oxygen to form oxygen ions. Hydrogen ions enter the cathode through the proton exchange membrane and combine with oxygen ions to form water. In the whole process, the chemical energy of hydrogen and oxygen is mainly converted into electrical energy. The system efficiency is high, and the only product is water, which is clean and pollution-free. Figure 2 For the existing hydrogen fuel cell system layout, the hydrogen supply system is connected to the anode of the hydrogen fuel cell, and the air supply system is mainly an air compressor and an axial flow fan, which provide cathode reaction gas for the fuel cell on the one hand, and provide the gas required for stack cooling on the other hand.

[0005] The advantage of fuel cells in energy density enables them to achieve long-range flight that is difficult to achieve with batteries, and can break through the limitation that batteries can only be used on small, short-range aircraft. However, there are also some problems with current fuel cell aviation propulsion systems: first, the air supply system of the fuel cell occupies a part of the system mass, and there is parasitic power during operation, which will reduce the power-to-weight ratio of the system, limiting its application in many aircraft; second, when the power of the fuel cell is further increased (>5 kW), other means (such as water cooling) are required to ensure heat dissipation, and these heat dissipation methods are heavier than air-cooled heat dissipation components, which will further seriously reduce the power-to-weight ratio of the system. Therefore, for high-power fuel cell aviation propulsion systems, how to improve the power-to-weight ratio of the system has become a problem that needs to be solved in this field in recent years. Summary of the invention

[0006] The purpose of the present invention is to address the above-mentioned technical problems and provide an aircraft engine driven by a fuel cell, in which the fuel cell and the aircraft engine are integrated into a structure design so that when the total output power of the fuel cell exceeds 5kW, the fuel cell can still be cooled by air cooling, thereby greatly improving the structural efficiency and power-to-weight ratio of the fuel cell aircraft engine.

[0007] In view of this, the present invention provides an aircraft engine driven by a fuel cell, comprising: The first drive motor, Ducted fan, The first stage fuel cell stack, The second stage fuel cell stack, and, a hydrogen supply system, Most of the airflow generated by the rotation of the ducted fan driven by the first drive motor is directly discharged backwards to generate the main thrust; a small part of the airflow first enters the first-stage fuel cell stack, provides the cathode of the first-stage fuel cell stack with oxygen required for the reaction and cools the stack, and after flowing through the first-stage fuel cell stack, this part of the airflow continues to flow into the second-stage fuel cell stack, provides the cathode of the second-stage fuel cell stack with oxygen required for the reaction and cools the stack; at the same time, the hydrogen supply system provides the anode of the first-stage fuel cell stack and the second-stage fuel cell stack with hydrogen required for the reaction.

[0008] Furthermore, the aero-engine driven by a fuel cell further comprises: A second drive motor and a propeller, wherein the propeller is arranged between the first-stage fuel cell stack and the second-stage fuel cell stack, and the second drive motor can drive the propeller to rotate, thereby accelerating and pressurizing the airflow after passing through the first-stage fuel cell stack, and the airflow accelerated and pressurized by the propeller continues to flow into the second-stage fuel cell stack, providing the cathode of the second-stage fuel cell stack with oxygen required for the reaction and cooling the stack.

[0009] Furthermore, the aero-engine driven by a fuel cell further comprises: A controller and a battery, wherein the controller is connected to the battery, the first drive motor and the second drive motor respectively, so that after the controller is connected to the battery, the battery can be used to supply power to the first drive motor and the second drive motor.

[0010] Furthermore, the controller is connected to the first-stage fuel cell stack and the second-stage fuel cell stack, so that the controller can supply power to the first drive motor and the second drive motor through the first-stage fuel cell stack and the second-stage fuel cell stack.

[0011] Furthermore, the controller is installed in the gap in the middle of the first-stage fuel cell stack, and the battery is installed in the gap in the middle of the second-stage fuel cell stack.

[0012] Furthermore, the fuel cell-driven aircraft engine selects the energy source of the first drive motor and the second drive motor by the controller according to the power demand: When the required power of the system is less than the maximum power of the first-stage fuel cell stack and the second-stage fuel cell stack, the controller selects the first-stage fuel cell stack and the second-stage fuel cell stack to power the first drive motor and the second drive motor, and uses the excess power to charge the battery until it is fully charged; When the required power is greater than the maximum power of the first-stage fuel cell stack and the second-stage fuel cell stack, the controller selects the first-stage fuel cell stack, the second-stage fuel cell stack and the battery to operate simultaneously to supply power to the first drive motor and the second drive motor.

[0013] Furthermore, the aero-engine driven by a fuel cell further comprises: a first-stage fixing frame and a second-stage fixing frame, wherein the first-stage fixing frame is used to install and fix the first-stage fuel cell stack, and the second-stage fixing frame is used to install and fix the second-stage fuel cell stack; The first-stage fixing frame and the second-stage fixing frame include an annular wall and a mounting frame installed in the annular wall.

[0014] Furthermore, the fuel cell-driven aviation engine also includes: a multi-section air guide cover, which is arranged around the periphery of the first-stage fuel cell stack and the second-stage fuel cell stack to guide the airflow entering the first-stage fuel cell stack and the second-stage fuel cell stack.

[0015] Furthermore, the deflector includes: A first section of the guide cover, which is used to guide the airflow flowing through the center of the ducted fan into the first section of the guide cover, so as to provide the cathode of the first stage fuel cell stack with gas required for reaction and cooling; The second section of the guide cover is used to guide the airflow flowing through the cathode of the first stage fuel cell stack into the propeller, so as to provide the cathode of the second stage fuel cell stack with gas required for reaction and cooling; The third section of the deflector is used to guide the airflow flowing through the cathode of the second-stage fuel cell stack out of the engine and provide a part of the thrust.

[0016] Furthermore, from the front end to the rear end of the engine, the cross-section of the first section of the air duct gradually expands backward along the main axis of the engine, the second section of the air duct is cylindrical, and its cross-section remains unchanged along the main axis of the engine, and the cross-section of the third section of the air duct gradually shrinks backward along the main axis of the engine.

[0017] Furthermore, the fuel cell-driven aircraft engine also includes: a third-stage fuel cell stack arranged at the rear end of the second-stage fuel cell stack, ..., an n-th stage fuel cell stack, wherein n≥2, and the airflow exhausted from the second-stage fuel cell stack sequentially enters the third-stage fuel cell stack, ..., the n-th stage fuel cell stack to provide the cathode with oxygen required for the reaction and cool the stack.

[0018] Furthermore, the third-stage fuel cell stack, ..., nth-stage fuel cell stack are configured with corresponding auxiliary drive motors and auxiliary propellers. The auxiliary drive motor can drive the auxiliary propeller connected thereto to rotate, and the airflow flowing through the previous-stage fuel cell stack is accelerated and pressurized by the auxiliary propeller and then flows into the next-stage fuel cell stack.

[0019] The beneficial effects of the present invention are: The present invention provides an aero-engine driven by a fuel cell, which abandons the simple serial working mode of the traditional electric propulsion power system, adopts a fusion design in structure and thermodynamics, and integrates the fuel cell and engine structure. On the one hand, the air supply system and cooling system of the traditional fuel cell system are abandoned, and the airflow generated by the ducted fan and the propeller is directly used to realize the supply of fuel cell cathode air and stack cooling; on the other hand, for a fuel cell aero-propulsion system with a larger power, such as a fuel cell aero-propulsion system with a power greater than 5 kW, water cooling and other methods are required, resulting in the problem of bulky cooling components, complex system structure, and low power-to-weight ratio. By distributing two or more fuel cell stack structures, an air-cooled cooling method can still be used under a larger power demand, and a larger power fuel cell aero-propulsion system under an air-cooled cooling method can be realized, which greatly improves the structural efficiency and power-to-weight ratio of the engine with a larger power. At the same time, the distributed stack arrangement form can make the power design of the fuel cell aero-propulsion system more flexible, which can meet different power requirements and is conducive to the application of fuel cells in the aero-propulsion system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the working principle of a hydrogen fuel cell; Figure 2 It is a schematic diagram of the structural layout of an existing fuel cell system; Figure 3 A schematic diagram of the structural layout of a fuel cell system of an aircraft engine driven by a fuel cell according to the present invention; Figure 4 A schematic diagram of the three-dimensional structure of an aviation engine driven by a fuel cell according to the present invention; Figure 5 This is a schematic diagram of the internal structure of an aircraft engine driven by a fuel cell according to the present invention; The symbols in the figure are: 1. Ducted fan; 2. First section air duct; 3. First stage fixing frame; 4. Second section air duct; 5. Second stage fixing frame; 6. Third section air duct; 7. First drive motor; 8. First stage fuel cell stack; 9. Controller; 10. Second drive motor; 11. Propeller; 12. Second stage fuel cell stack; 13. Battery. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0022] In the description of the present application, it should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. For ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0024] It should be noted that, in the description of the present application, the orientation or positional relationship indicated by terms such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise stated, these orientation words 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 cannot be understood as limiting the scope of protection of the present application; the orientation words "inside and outside" refer to the inside and outside relative to the contour of each component itself.

[0025] It should be noted that, in the present application, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises one..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be noted that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0026] like Figures 3-5 As shown, the present invention provides an aircraft engine driven by a fuel cell, comprising: The first drive motor 7, Ducted fan 1, The first stage fuel cell stack 8, The second stage fuel cell stack 12, and, a hydrogen supply system, Most of the airflow generated by the rotation of the ducted fan 1 driven by the first driving motor 7 is directly discharged backwards to generate the main thrust; a small part of the airflow first enters the first-stage fuel cell stack 8, provides the cathode of the first-stage fuel cell stack 8 with the oxygen required for the reaction and cools the stack, and after flowing through the first-stage fuel cell stack 8, this part of the airflow continues to flow into the second-stage fuel cell stack 12, provides the cathode of the second-stage fuel cell stack 12 with the oxygen required for the reaction and cools the stack; at the same time, the hydrogen supply system provides the anodes of the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12 with the hydrogen required for the reaction.

[0027] Preferably, 60% to 90% of the total airflow generated by the rotation of the ducted fan 1 is directly discharged backwards to generate the main thrust, and the remaining airflow enters the first-stage fuel cell stack 8.

[0028] Furthermore, the aero-engine driven by a fuel cell further comprises: The second drive motor 10 and the propeller 11, wherein the propeller 11 is arranged between the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12, and the second drive motor 10 can drive the propeller 11 to rotate, thereby accelerating and pressurizing the airflow after passing through the first-stage fuel cell stack 8, and the airflow accelerated and pressurized by the propeller 11 continues to flow into the second-stage fuel cell stack 12, providing the cathode of the second-stage fuel cell stack 12 with oxygen required for the reaction and cooling the stack.

[0029] Furthermore, the aero-engine driven by a fuel cell further comprises: The controller 9 and the battery 13 are connected to the battery 13 , the first drive motor 7 , and the second drive motor 10 , respectively, so that the controller 9 can supply power to the first drive motor 7 and the second drive motor 10 through the battery 13 after being connected to the battery 13 .

[0030] Furthermore, the controller 9 is also connected to components such as the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12 , so that the controller 9 can power the first drive motor 7 and the second drive motor 10 through the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12 .

[0031] As a preferred example of the present invention, the fuel cell-driven aviation engine system provided by the present invention can also select the energy source of the first drive motor 7 and the second drive motor 10 by the controller 9 according to the power demand, thereby driving the ducted fan 1 to generate thrust and the airflow required by the first-stage fuel cell stack 8, and driving the propeller 11 to provide the airflow required by the second-stage fuel cell stack 12, thereby achieving continuous operation.

[0032] Specifically, when the required power of the system is less than the maximum power of the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12, the controller 9 selects the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12 to power the first drive motor 7 and the second drive motor 10, and uses the excess power to charge the battery 13 until it is fully charged; when the required power is greater than the maximum power of the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12, the controller 9 selects the first-stage fuel cell stack 8, the second-stage fuel cell stack 12 and the battery 13 to work simultaneously to power the first drive motor 7 and the second drive motor 10 to meet the power demand.

[0033] As some examples of the present invention, the fuel cell-driven aviation engine further includes: a plurality of fixing frames, which are used to install fuel cell stacks, such as the first-stage fuel cell stack 8, the second-stage fuel cell stack 12 and other components.

[0034] Specifically, the fixing frame includes: The first-stage fixing frame 3 and the second-stage fixing frame 5 , wherein the first-stage fixing frame 3 is used to install and fix the first-stage fuel cell stack 8 , and the second-stage fixing frame 5 is used to install and fix the second-stage fuel cell stack 12 .

[0035] Preferably, Figures 4 and 5 As shown, the first-stage fixing frame 3 and the second-stage fixing frame 5 include an annular wall and a mounting frame installed in the annular wall. The annular wall can be used to connect with the air guide cover described later, and the mounting frame is used to connect with the fuel cell stack. The specific shape and structure of the mounting frame can be set according to the needs of installing the fuel cell stack.

[0036] As some examples of the present invention, the fuel cell-driven aviation engine also includes: a multi-section air guide cover, which is arranged around the periphery of the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12, and is used to guide the airflow entering the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12.

[0037] Specifically, the deflector includes: A first section air guide hood 2, which is fixed to the first stage fixing frame 3 by bolts and other connecting parts, and is used to guide the airflow flowing through the center of the ducted fan 1 into the first section air guide hood 2, so as to provide the cathode of the first stage fuel cell stack 8 with gas required for reaction and cooling; The second section of the guide cover 4 is fixed between the first-stage fixing frame 3 and the second-stage fixing frame 5 by bolts and other connecting parts, and is used to guide the airflow flowing through the cathode of the first-stage fuel cell stack 8 into the propeller 11, so as to provide the cathode of the second-stage fuel cell stack 12 with the gas required for reaction and cooling; The third section air deflector 6 is fixed to the second stage fixing frame 5 by bolts and other fasteners, and is used to guide the airflow flowing through the cathode of the second stage fuel cell stack 12 out of the engine and provide a small part of thrust.

[0038] Preferably, from the front end to the rear end of the engine, the cross-section of the first section of the air duct 2 gradually expands backward along the main axis of the engine, the second section of the air duct 4 is cylindrical, and its cross-section remains unchanged along the direction of the main axis of the engine, and the cross-section of the third section of the air duct 6 gradually shrinks backward along the main axis of the engine.

[0039] In addition, the connection method between other components in the aero-engine driven by fuel cells is described as follows: The ducted fan 1 is fixed on the motor shaft of the first drive motor 7 and driven by the first drive motor 7 to generate thrust and realize the propulsion function, and at the same time provide the cathode of the fuel cell stack with gas required for reaction and cooling; The first driving motor 7 is fixed to the front end of the first-stage fixing frame 3 by means of bolts or other connecting parts, and is used to drive the ducted fan 1 to rotate; The front and rear ends of the center of the first-stage fixing frame 3 are respectively connected to the first drive motor 7 and the second drive motor 10 through bolts and other connecting parts, so as to fix the first drive motor 7 and the second drive motor 10. The front and rear ends of the edge of the annular wall are respectively connected to the first section flow guide cover 2 and the second section flow guide cover 4 through bolts and other connecting parts, so as to fix the first section flow guide cover 2 and the second section flow guide cover 4. The middle of the annular wall is connected to the first-stage fuel cell stack 8 through bolts and other connecting parts, so as to fix the first-stage fuel cell stack 8. The first-stage fuel cell stack 8 is fixed on the first-stage fixing frame 3, and outputs electric energy under the reaction of fuel and air, which is used to provide power for partially driving the first drive motor 7 and the second drive motor 10 to work continuously; The second drive motor 10 is fixed to the rear end of the center of the first-stage fixing frame 3 by bolts or other connecting parts, and is used to drive the propeller 11 to rotate, so as to accelerate and pressurize the gas flowing through the cathode of the first-stage fuel cell stack 8; The propeller 11 is fixed on the motor shaft of the second drive motor 10 and driven by the second drive motor 10 to accelerate and pressurize the gas flowing through the cathode of the first-stage fuel cell stack 8, so that the airflow flowing through the first-stage fuel cell stack 8 can quickly flow into the second-stage fuel cell stack 12; The front and rear ends of the second-stage fixing frame 5 are respectively connected to the second-stage flow guide cover 4 and the third-stage flow guide cover 6 by bolts and other fixing parts, so as to fix the second-stage flow guide cover 4 and the third-stage flow guide cover 6, and the middle of the annular wall is connected to the second-stage fuel cell stack 12 by bolts and other connecting parts, so as to fix the second-stage fuel cell stack 12; The second-stage fuel cell stack 12 is fixed to the second-stage fixing frame 5 by bolts and other connecting parts, and outputs electric energy under the reaction of fuel and air, which is used to provide power for partially driving the first drive motor 7 and the second drive motor 10 to work continuously; The controller 9 is fixed in the middle gap of the first-stage fuel cell stack 8, and is used to monitor the working status of the battery 13, the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12, and the energy destination of the battery 13, the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12; The battery 13 is fixed in the middle gap of the second-stage fuel cell stack 12, and is used to supply power when the engine is started. When the engine power demand is greater than the maximum power that the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12 can provide, the battery 13 outputs power together with the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12 to supply power to the first drive motor 7 and the second drive motor 10.

[0040] Preferably, the ducted fan 1 is a metal fan.

[0041] Preferably, the materials of the first section air guide cover 2, the second section air guide cover 4 and the third section air guide cover 6 are epoxy resin or carbon fiber etc. which are light in weight and high in strength and rigidity.

[0042] Preferably, the material of the first-stage fixing frame 3 and the second-stage fixing frame 5 is alloy steel or titanium alloy with high strength, good toughness and excellent welding performance, and the first-stage fixing frame 3 and the second-stage fixing frame 5 are connected to the body and the air duct by welding or bolting.

[0043] Preferably, the first drive motor 7 and the second drive motor 10 are high-power permanent magnet synchronous motors or brushless DC motors.

[0044] Preferably, the first-stage fuel cell stack 8 and the second-stage fuel cell stack 12 are graphite stacks or metal stacks, and the fuel used is preferably hydrogen or methanol. When the fuel used is methanol, the hydrogen supply system is a methanol supply system, which is used to supply methanol to the two-stage fuel cell stacks.

[0045] Preferably, the propeller 11 is a carbon fiber propeller, a wooden propeller or a composite material propeller.

[0046] Preferably, the storage battery 13 is a secondary battery such as a lithium battery.

[0047] Preferably, the first-stage fuel cell stack 8 is mounted on the first-stage fixing frame 3, and the flow direction of the cathode flow channel in the first-stage fuel cell stack 8 is parallel to the flight direction; the first drive motor 7 and the second drive motor 10 are respectively mounted on the front and rear sides of the first-stage fixing frame 3, parallel to the flow direction of the cathode flow channel of the first-stage fuel cell stack 8. Among them, the first drive motor 7 is mounted at the front end of the first-stage fuel cell stack 8, and its motor shaft is oriented in the same direction as the flight direction; the ducted fan 1 is mounted on the motor shaft of the first drive motor 7, which is mainly used to provide the thrust required by the engine; the second drive motor 10 is mounted at the rear end of the first-stage fuel cell stack 8, and the motor shaft is oriented in the opposite direction to the flight direction; the propeller 11 is mounted on the motor shaft of the second drive motor 10. The second-stage fuel cell stack 12 is mounted on the second-stage fixing frame 5, and the second-stage fixing frame 5 and the second-stage fuel cell stack 12 are mounted at the rear end of the second drive motor 10. The first section air deflector 2, the second section air deflector 4 and the third section air deflector 6 are respectively installed between the first stage fixing frame 6 and the ducted fan 1, between the first stage fixing frame 3 and the second stage fixing frame 5 and at the rear end of the second stage fixing frame 5, and together with the fixing frame, form a relatively closed inner duct area, which is used to introduce a part of the air flow after passing through the ducted fan 1 into the two-stage fuel cell stack, and to discharge the exhaust gas flowing through the two-stage fuel cell stack backward. The fuel source of the hydrogen supply system is installed inside the aircraft, and the fuel is introduced into the fuel cell stack through the fuel inlet arranged beside the first stage fuel cell stack 8 and the second stage fuel cell stack 12 and then discharged through the fuel outlet; the battery 13 is installed at the center of the second stage fuel cell stack 12 on the axis of the engine and is connected to the controller 9; the controller 9 is installed at the center of the first stage fuel cell stack 8 on the axis of the engine, and can monitor the working status of the fuel cell stack and the battery 13 and control the switch of the fuel supply system.

[0048] As some examples of the present invention, the fuel cell-driven aviation engine also includes: a third-stage fuel cell stack, ..., an n-th stage fuel cell stack, arranged at the rear end of the second-stage fuel cell stack 12, wherein n≥2, preferably n≥3, and the airflow exhausted from the second-stage fuel cell stack 12 enters the third-stage fuel cell stack, ..., the n-th stage fuel cell stack in sequence to provide the cathode with oxygen required for the reaction and cool the stack.

[0049] Furthermore, the third-stage fuel cell stack, ..., nth-stage fuel cell stack are configured with corresponding auxiliary drive motors and auxiliary propellers. The auxiliary drive motor can drive the auxiliary propeller connected thereto to rotate, and the airflow flowing through the previous-stage fuel cell stack is accelerated and pressurized by the auxiliary propeller and then flows into the next-stage fuel cell stack.

[0050] The fuel cell stack structure of the fuel cell-driven aircraft engine described in the present invention is not limited to two stages. It can also increase the number of stack stages after the second-stage fuel cell stack 12 according to power requirements and in the same configuration as the second-stage fuel cell stack 12, and be equipped with necessary auxiliary motors and auxiliary propellers to increase the overall output power of the engine and meet greater power requirements.

[0051] Therefore, it can be understood that the third-level fuel cell stack,..., nth-level fuel cell stack can be regarded as a repeating unit of the second-level fuel cell stack 12, and the structure, configuration and connection method between the third-level fuel cell stack,..., nth-level fuel cell stack and other components can be carried out with reference to the second-level fuel cell stack 12.

[0052] Taking the structure including a two-stage fuel cell stack as an example, the working principle of the fuel cell driven engine of the present invention is explained: first, the controller 9 connects to the battery 13 to power the first drive motor 7 and the second drive motor 10, and the first drive motor 7 and the second drive motor 10 work and respectively drive the ducted fan 1 and the propeller 11 to rotate to generate airflow, wherein most of the airflow generated by the ducted fan 1 is directly discharged backward to generate the main thrust; a small part of the airflow enters the inner duct through the first section of the guide cover 2, and first enters the first stage fuel cell stack 8 to provide the required oxygen for the reaction and cool the stack; after flowing through the first stage fuel cell stack 8, the airflow is accelerated and pressurized again in the second section of the guide cover 4 by the propeller 11 driven by the second drive motor 10, and flows into the second stage fuel cell stack 12, providing the cathode of the second stage fuel cell stack 12 with the air required for reaction and cooling, and finally is accelerated and discharged through the outlet of the third section of the guide cover 6 to provide a small part of the supplementary thrust for the engine. At the same time, the hydrogen supply system provides the fuel required for the reaction to the anode of the two-stage fuel cell stack from the fuel inlet of the two-stage fuel cell stack, the two-stage fuel cell stack group starts to run and outputs electric power, and the controller 9 switches the energy source of each drive motor to the fuel cell. After that, the engine can select the energy source of the first drive motor 7 and the second drive motor 10 by the controller 9 according to the power demand, drive the ducted fan 1 to generate thrust and the airflow required by the first-stage fuel cell stack 8, and drive the propeller 11 to provide the airflow required by the second-stage fuel cell stack 12 to achieve continuous operation. When the power required by the engine is greater than the total power output by the two-stage fuel cell stack group, the battery 13 and the two-stage fuel cell stack group work simultaneously to provide power to the engine together; when the power required by the engine is not greater than the total power output by the two-stage fuel cell stack group, the two-stage fuel cell stack group provides power to the engine, and uses the excess power to charge the battery 13, so as to achieve continuous operation of the engine under various working conditions.

[0053] The present invention provides an aero-engine driven by a fuel cell, which abandons the simple series working mode of the traditional electric propulsion power system, adopts a fusion design in structure and thermodynamics, and integrates the fuel cell and the engine structure. On the one hand, the air supply system and cooling system of the traditional fuel cell system are abandoned, and the airflow generated by the ducted fan 1 and the propeller 11 is directly used to realize the supply of fuel cell cathode air and stack cooling; on the other hand, for a fuel cell aero-propulsion system with a relatively large power, such as a fuel cell aero-propulsion system with a power greater than 5 kW, water cooling and other methods are required, resulting in the problem of bulky cooling components, complex system structure, and low power-to-weight ratio. By arranging a two-stage fuel cell stack structure in a distributed manner, an air-cooled cooling method can still be used under a relatively large power demand, and a relatively large power fuel cell aero-propulsion system under an air-cooled cooling method can be realized, which greatly improves the structural efficiency and power-to-weight ratio of the relatively large power engine. At the same time, the distributed stack arrangement form can make the power design of the fuel cell aero-propulsion system more flexible, which can meet different power requirements and is conducive to the application of fuel cells in the aero-propulsion system.

[0054] In addition, the fuel cell-driven aircraft engine of the present invention has only three types of rotating parts, namely, the ducted fan 1, the propeller 11 and the drive motor, which has the advantage of low noise compared with traditional aircraft engines. At the same time, the present invention is an all-electric aviation propulsion system, which does not have a fuel combustion process, has a low operating temperature of the whole machine, and has good infrared stealth; the product of the fuel reaction chemical process involved in the present invention is water, and the emission products are residual fuel and oxygen, without various nitrogen oxides of traditional aircraft engines, so it has zero emissions, no pollution, and is environmentally friendly.

[0055] In summary, the fuel cell-driven aviation engine of the present invention has the following advantages: (1) The present invention integrates the fuel cell with the traditional aircraft engine structure. On the one hand, the air supply system in the original fuel cell system is abandoned, and the airflow behind the ducted fan and propeller is used to directly provide the cathode of the fuel cell with the air required for reaction and cooling, which can improve the structural efficiency of the entire system and the power-to-weight ratio of the whole machine; on the other hand, the present invention adopts a distributed fuel cell arrangement method to address the problem that the power-to-weight ratio of the system is relatively low when the engine power is large, such as the need to use complex cooling methods such as water cooling. For a large-power fuel cell aviation propulsion system, the power-to-weight ratio of the system can be greatly improved. In addition, the present invention has only three types of rotating parts, namely, the ducted fan, the propeller and the drive motor, which has the advantage of low noise compared to traditional aircraft engines; at the same time, the present invention is an all-electric aviation propulsion system, without the combustion process of fuel, the operating temperature of the whole machine is low, and the infrared stealth is good; and the product of the fuel reaction chemical process involved in the present invention is water, and the emission products are residual fuel and oxygen, without various nitrogen oxides of traditional aircraft engines, so there is zero emission, no pollution, and it is environmentally friendly.

[0056] (2) The cross-section of the first section of the guide cover of the present invention gradually expands backward, which can reduce the speed of the airflow after the duct fan, increase the pressure and temperature of the airflow, and help the airflow to further flow into the fuel cell to participate in the reaction; the cross-section of the third section of the guide cover gradually shrinks backward, which can increase the speed of the airflow after the second-stage fuel cell, and help increase the additional thrust generated after the airflow flows out of the guide cover.

[0057] (3) In the present invention, the airflow passing through the duct fan and entering the duct, after passing through the first and second drive motors and the controller and other components, can use the heat generated by the drive motors and the controller to heat the airflow in the duct, thereby reducing the impact of the low temperature of the gas flow on the performance of the fuel cell stack under aviation flight conditions.

[0058] (4) The fuel cell stack in the present invention adopts a graphite stack or a metal stack, which is light in weight and has a high power-to-weight ratio.

[0059] (5) The fuel used in the fuel cell stack of the present invention is hydrogen, and the only product of its electrochemical reaction is water, which has the advantages of being clean and pollution-free.

[0060] (6) The propeller in the present invention is made of carbon fiber propeller, wooden propeller or composite material propeller, which is light in weight and has good aerodynamic performance.

[0061] (7) The drive motor in the present invention is a permanent magnet synchronous motor or a brushless DC motor, which has large torque, high power density and high efficiency.

[0062] (8) The two-stage fixing frame in the present invention is made of alloy steel or titanium alloy, which has high strength and good toughness.

[0063] (9) The three-section fairing in the present invention is made of epoxy resin or carbon fiber material, which is light in weight and high in strength and rigidity.

[0064] (10) The fuel cell-driven aircraft engine of the present invention adopts a distributed stack arrangement. After the second-stage fuel cell stack of the example, the number of stacks can be increased as needed in the same configuration as the second-stage fuel cell stack, and equipped with necessary auxiliary motors and auxiliary propellers, so that the power design of the fuel cell aviation propulsion system is more flexible and can meet different power requirements.

[0065] The embodiments of the present application are described above in conjunction with the accompanying drawings. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. An aircraft engine driven by a fuel cell, characterized in that: include: The first drive motor (7), Ducted fan (1), The first stage fuel cell stack (8), The second stage fuel cell stack (12), and, a hydrogen supply system, Most of the airflow generated by the rotation of the ducted fan (1) driven by the first drive motor (7) is directly discharged backwards to generate the main thrust; a small part of the airflow first enters the first-stage fuel cell stack (8) to provide the cathode of the first-stage fuel cell stack (8) with oxygen required for the reaction and cool the stack; after flowing through the first-stage fuel cell stack (8), this part of the airflow continues to flow into the second-stage fuel cell stack (12) to provide the cathode of the second-stage fuel cell stack (12) with oxygen required for the reaction and cool the stack; at the same time, the hydrogen supply system provides the anodes of the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12) with hydrogen required for the reaction.

2. The fuel cell-driven aircraft engine according to claim 1, characterized in that: The aero-engine driven by a fuel cell also includes: A second drive motor (10) and a propeller (11), wherein the propeller (11) is arranged between the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12), and the second drive motor (10) can drive the propeller (11) to rotate, thereby accelerating and pressurizing the airflow after flowing through the first-stage fuel cell stack (8), and the airflow accelerated and pressurized by the propeller (11) continues to flow into the second-stage fuel cell stack (12), thereby providing oxygen required for the reaction of the cathode of the second-stage fuel cell stack (12) and cooling the stack.

3. The fuel cell-driven aircraft engine according to claim 1, characterized in that: The aero-engine driven by a fuel cell also includes: A controller (9) and a battery (13), wherein the controller (9) is respectively connected to the battery (13), the first drive motor (7), and the second drive motor (10), so that after the controller (9) is connected to the battery (13), the battery (13) can supply power to the first drive motor (7) and the second drive motor (10); The controller (9) is also connected to the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12), so that the controller (9) can also supply power to the first drive motor (7) and the second drive motor (10) through the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12).

4. The fuel cell-driven aircraft engine according to claim 3, characterized in that: The controller (9) is installed in the gap in the middle of the first-stage fuel cell stack (8), and the storage battery (13) is installed in the gap in the middle of the second-stage fuel cell stack (12).

5. The fuel cell-driven aircraft engine according to claim 3, characterized in that: The fuel cell-driven aviation engine selects the energy source of the first drive motor (7) and the second drive motor (10) by a controller (9) according to power demand: When the required power of the system is less than the maximum power of the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12), the controller (9) selects the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12) to supply power to the first drive motor (7) and the second drive motor (10), and simultaneously utilizes the surplus power to charge the storage battery (13) until it is fully charged; When the required power is greater than the maximum power of the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12), the controller (9) selects the first-stage fuel cell stack (8), the second-stage fuel cell stack (12) and the battery (13) to operate simultaneously to supply power to the first drive motor (7) and the second drive motor (10).

6. The fuel cell-driven aircraft engine according to claim 2, characterized in that: The fuel cell-driven aviation engine further comprises: a multi-section air guide cover, the air guide cover being arranged around the periphery of the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12) and being used to guide the airflow entering the first-stage fuel cell stack (8) and the second-stage fuel cell stack (12).

7. The fuel cell-driven aircraft engine according to claim 6, characterized in that: The deflector comprises: A first section flow guide cover (2) is used to guide the airflow flowing through the center of the ducted fan (1) into the first section flow guide cover (2) to provide the cathode of the first stage fuel cell stack (8) with gas required for reaction and cooling; A second section of the guide cover (4) is used to guide the airflow flowing through the cathode of the first stage fuel cell stack (8) into the propeller (11), so as to provide the cathode of the second stage fuel cell stack (12) with gas required for reaction and cooling; The third section of the guide cover (6) is used to guide the airflow flowing through the cathode of the second-stage fuel cell stack (12) out of the engine and provide a part of the thrust.

8. The fuel cell-driven aircraft engine according to claim 7, characterized in that: From the front end to the rear end of the engine, the cross section of the first section of the air duct (2) gradually expands backward along the main axis of the engine, the second section of the air duct (4) is cylindrical, and its cross section remains unchanged along the main axis of the engine, and the cross section of the third section of the air duct (6) gradually contracts backward along the main axis of the engine.

9. The fuel cell-driven aircraft engine according to claim 1, characterized in that: The fuel cell-driven aircraft engine further comprises: a third-stage fuel cell stack, ..., an n-th stage fuel cell stack, arranged at the rear end of the second-stage fuel cell stack (12), wherein n≥2, and the airflow exhausted from the second-stage fuel cell stack (12) sequentially enters the third-stage fuel cell stack, ..., the n-th stage fuel cell stack, to provide oxygen required for the reaction to the cathode thereof and to cool the stack.

10. The fuel cell-driven aviation engine according to claim 9, characterized in that: The third-stage fuel cell stack, ..., and the nth-stage fuel cell stack are configured with corresponding auxiliary drive motors and auxiliary propellers. The auxiliary drive motor can drive the auxiliary propeller connected to it to rotate, and the airflow flowing through the previous-stage fuel cell stack is accelerated and pressurized by the auxiliary propeller and then flows into the next-stage fuel cell stack.

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