An aircraft engine driven by a fuel cell

Abstract

The application 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 airflow generated by the rotation of the ducted fan driven by the first driving motor is mostly directly discharged backward to generate main thrust. A small part of the airflow first enters the first-stage fuel cell stack to provide oxygen for the cathode of the first-stage fuel cell stack and cool the stack. After flowing through the first-stage fuel cell stack, the airflow continues to flow into the second-stage fuel cell stack to provide oxygen for the cathode of the second-stage fuel cell stack and cool the stack. The aero-engine driven by the fuel cell of the application combines the fuel cell with the structure of the aero-engine for design, and can still adopt air cooling to cool the fuel cell under the condition that the total output power of the fuel cell exceeds 5 kW.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engines, in particular to an aero-engine driven by a fuel cell. BACKGROUND

[0002] With the environmental problems caused by fossil fuels, the electric propulsion system occupies an increasingly important position in the field of aviation power due to its advantages of no environmental pollution, high control accuracy and fast response. At present, many countries in the world have begun to accelerate the development of aviation electric propulsion systems.

[0003] The existing electric propulsion power system mainly includes a propeller, a motor, a controller and a battery, etc. The propeller can be mainly divided into a propeller and a ducted fan, the motor is generally a permanent magnet synchronous motor, and the battery is generally a high-power-density storage battery such as a lithium battery. However, the energy density of the storage battery in the existing electric propulsion power system is relatively low (<300 Wh / kg), which seriously limits the endurance time of the system.

[0004] Compared with the storage battery, the fuel cell has a higher energy density (such as a wind-cooled hydrogen fuel cell with an energy density >1000 Wh / kg), which is one of the technical solutions to improve the endurance time of the aviation electric propulsion power system. Taking a hydrogen fuel cell as an example, Figure 1 The working principle of the hydrogen fuel cell is that hydrogen gas enters the anode and loses electrons to become hydrogen ions. The electrons pass through the external circuit to generate current and flow into the cathode to combine with oxygen to form oxygen ions. The hydrogen ions pass through the proton exchange membrane into the cathode to combine with the oxygen ions to form water. The chemical energy of hydrogen and oxygen is mainly converted into electrical energy in the whole process, the system has high efficiency, and the only product is water, which is clean and pollution-free. Figure 2 The existing hydrogen fuel cell system layout is that the hydrogen supply system is connected with the anode of the hydrogen fuel cell, and the air supply system mainly includes an air compressor and an axial fan, which provides cathode reaction gas for the fuel cell and provides gas required for electric pile cooling.

[0005] The advantage of the fuel cell in energy density enables it to realize long-endurance flight that the storage battery cannot achieve, and breaks through the limitation that the storage battery can only be applied to small short-range aircraft. However, the current fuel cell aviation propulsion system also has some problems: first, the air supply system of the fuel cell occupies part of the system mass, and there is parasitic power in the running process, which will reduce the power-to-weight ratio of the system and limit its application on many aircraft; second, when the power of the fuel cell is further increased (>5 kW), other means (such as water cooling) are needed to ensure heat dissipation, and these heat dissipation methods have a larger mass than the air-cooled heat dissipation components, which will further seriously reduce the power-to-weight ratio of the system. Therefore, for a fuel cell aviation propulsion system with a larger power, how to improve the power-to-weight ratio of the system has become a problem to be solved in this field in recent years. SUMMARY

[0006] The present application aims at providing an aircraft engine driven by fuel cells, which integrates the fuel cells with the structure of the aircraft engine, and realizes the air cooling of the fuel cells even when the total output power of the fuel cells exceeds 5kW, thereby greatly improving the structural efficiency and power-to-weight ratio of the aircraft engine driven by fuel cells.

[0007] Therefore, the present application provides an aircraft engine driven by fuel cells, which comprises:

[0008] a first driving motor,

[0009] a ducted fan,

[0010] a first fuel cell stack,

[0011] a second fuel cell stack,

[0012] a hydrogen supply system,

[0013] The first driving motor drives the rotation of the ducted fan to generate air flow, most of which is directly discharged backward to generate main thrust, and a small part of which first enters the first fuel cell stack to provide oxygen required for the reaction of the cathode of the first fuel cell stack and cool the stack, and then continues to flow into the second fuel cell stack to provide oxygen required for the reaction of the cathode of the second fuel cell stack and cool the stack. Meanwhile, the hydrogen supply system provides hydrogen required for the reaction of the anode of the first fuel cell stack and the second fuel cell stack, respectively.

[0014] Further, the aircraft engine driven by fuel cells further comprises:

[0015] a second driving motor and a propeller, the propeller is arranged between the first fuel cell stack and the second fuel cell stack, and the second driving motor can drive the rotation of the propeller to accelerate and pressurize the air flow after flowing through the first fuel cell stack, and the air flow after being accelerated and pressurized by the propeller continues to flow into the second fuel cell stack to provide oxygen required for the reaction of the cathode of the second fuel cell stack and cool the stack.

[0016] Further, the aircraft engine driven by fuel cells further comprises:

[0017] a controller and a storage battery, the controller is connected with the storage battery, the first driving motor and the second driving motor, respectively, so that the controller can supply power to the first driving motor and the second driving motor through the storage battery after the controller is connected with the storage battery.

[0018] Further, the controller is connected to the first stage fuel cell stack and the second stage fuel cell stack, such 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.

[0019] Further, 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.

[0020] Further, the fuel cell driven aeroengine selects the energy source of the first drive motor and the second drive motor according to the power demand by the controller:

[0021] When the demand 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 to supply power to the first drive motor and the second drive motor by the first stage fuel cell stack and the second stage fuel cell stack, and at the same time, uses the excess power to charge the battery until it is full;

[0022] When the demand power is greater than the maximum power of the first stage fuel cell stack and the second stage fuel cell stack, the controller selects to supply power to the first drive motor and the second drive motor by the first stage fuel cell stack, the second stage fuel cell stack and the battery working at the same time.

[0023] Further, the fuel cell driven aeroengine further comprises:

[0024] 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;

[0025] The first stage fixing frame and the second stage fixing frame comprise a ring wall and a mounting frame installed in the ring wall.

[0026] Further, the fuel cell driven aeroengine further comprises: a multi-section fairing, which is arranged around the periphery of the first stage fuel cell stack and the second stage fuel cell stack, and is used to guide the airflow entering the first stage fuel cell stack and the second stage fuel cell stack.

[0027] Further, the fairing comprises:

[0028] The first section fairing is used to guide the airflow flowing through the center of the ducted fan into the first section fairing, so as to provide the gas required for reaction and cooling of the cathode of the first stage fuel cell stack;

[0029] The second section of the fairing is used to guide the air flow through the cathode of the first stage fuel cell stack into the propeller, and to provide the air required for the reaction and cooling of the cathode of the second stage fuel cell stack.

[0030] The third section of the fairing is used to guide the air flow through the cathode of the second stage fuel cell stack out of the engine, and to provide a part of the thrust.

[0031] Further, from the front end to the rear end of the engine, the cross section of the first section of the fairing gradually expands along the main axis of the engine, the cross section of the second section of the fairing is cylindrical and does not change along the main axis of the engine, and the cross section of the third section of the fairing gradually shrinks along the main axis of the engine.

[0032] Further, the fuel cell driven aero-engine further comprises a third stage fuel cell stack, a fourth stage fuel cell stack, and an nth stage fuel cell stack arranged at the rear end of the second stage fuel cell stack, wherein n is greater than or equal to 2, and the air flow discharged from the second stage fuel cell stack enters the third stage fuel cell stack, the fourth stage fuel cell stack, and the nth stage fuel cell stack in sequence, to provide the oxygen required for the reaction and cooling of the cathode of the fuel cell stack.

[0033] Further, the third stage fuel cell stack, the fourth stage fuel cell stack, and the nth stage fuel cell stack are provided with corresponding auxiliary driving motors and auxiliary propellers, the auxiliary driving motor can drive the auxiliary propeller connected thereto to rotate, and the air flow 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.

[0034] The beneficial effects of the present application are:

[0035] The present application provides a fuel cell driven aero-engine, which abandons the simple series working mode of the traditional electric propulsion power system, and adopts a fusion design in structure and thermodynamics, which fuses the fuel cell and the engine structure. On the one hand, the air supply system and the cooling system of the traditional fuel cell system are abandoned, and the air flow generated by the ducted fan and the propeller is directly used to supply the air for the cathode of the fuel cell and to cool the fuel cell stack. On the other hand, for a larger power, such as a fuel cell aviation propulsion system with a power greater than 5 kW, water cooling is required, which results in a heavy cooling component, a complex system structure, and a low power-to-weight ratio. Through the distributed arrangement of two or more stages of fuel cell stacks, the wind cooling mode can still be used under a larger power requirement, a larger power fuel cell aviation propulsion system under the wind cooling mode is realized, the structural efficiency and the power-to-weight ratio of the larger power engine are greatly improved, and the distributed stack arrangement form can make the power design of the fuel cell aviation propulsion system more flexible, so as to meet different power requirements, which is conducive to the application of fuel cells in aviation propulsion systems. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic diagram of the working principle of a hydrogen fuel cell;

[0037] Figure 2 is a schematic diagram of the structural layout of an existing fuel cell system;

[0038] Figure 3 is a schematic diagram of the structural layout of a fuel cell system for a fuel cell driven aero-engine according to the present application;

[0039] Figure 4 is a schematic diagram of the structural layout of a fuel cell system for a fuel cell driven aero-engine according to the present application;

[0040] Figure 5 is a schematic diagram of the structural layout of a fuel cell system for a fuel cell driven aero-engine according to the present application;

[0041] The symbols in the drawings represent:

[0042] 1. ducted fan; 2. first section of fairing; 3. first stage mount; 4. second section of fairing; 5. second stage mount; 6. third section of fairing; 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

[0043] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art belong to the scope of protection of the present application.

[0044] In the description of the present application, it should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. For the convenience of description, the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship. The technology, methods and devices known to those skilled in the art can not be discussed in detail, but should be considered as part of the authorized description. In all the examples shown and discussed herein, any specific value should be interpreted as merely exemplary, and not as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numerals 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.

[0045] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application are used for distinguishing between similar objects and are not necessarily used to describe a particular sequential or chronological order. It is to be understood that the use of the terms so construed can interchange depending on the context in which it is used, and that the embodiments of the present application can be accordingly carried out without those specifically recited features. The scope of the application is, therefore, indicated by the appended claims rather than by the foregoing description. Also, the same reference numerals in different drawings denote the same or similar functionalities.

[0046] It should be noted that in the description of the present application, the terms of orientation such as "front", "back", "up", "down", "left", "right", "transverse", "vertical", "horizontal", "top", "bottom", and the like indicate the orientation or positional relationship shown in the drawings, which are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the scope of protection of the present application. The terms "inner" and "outer" refer to the inner and outer relative to the contour of the components themselves.

[0047] It should be noted that in the present application, the terms "comprise", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or device comprising the element. In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, but can also include performing functions in a substantially simultaneous manner or in reverse order, for example, the described method can be performed in an order different from that described, and various steps can also be added, omitted or combined. In addition, the features described with reference to certain examples can be combined in other examples.

[0048] As shown in Figures 3-5 The present application provides an aircraft engine driven by fuel cells, comprising:

[0049] a first drive motor 7,

[0050] a ducted fan 1,

[0051] a first stage fuel cell stack 8,

[0052] the second stage fuel cell stack 12,

[0053] and a hydrogen supply system,

[0054] The first driving motor 7 drives the ducted fan 1 to rotate to generate air flow, most of which is directly discharged backward to generate main thrust; a small part of the air flow first enters the first stage fuel cell stack 8 to provide oxygen required for the reaction of the cathode of the first stage fuel cell stack 8 and to cool the stack, and then continues to flow into the second stage fuel cell stack 12 to provide oxygen required for the reaction of the cathode of the second stage fuel cell stack 12 and to cool the stack; at the same time, the hydrogen supply system provides hydrogen required for the reaction of the anode of the first stage fuel cell stack 8 and the second stage fuel cell stack 12, respectively.

[0055] Preferably, 60% to 90% of the total air flow generated by the rotation of the ducted fan 1 is directly discharged backward to generate main thrust, and the remaining air flow enters the first stage fuel cell stack 8.

[0056] Further, the fuel cell driven aero-engine further comprises:

[0057] a second driving motor 10 and a propeller 11, the propeller 11 being arranged between the first stage fuel cell stack 8 and the second stage fuel cell stack 12, the second driving motor 10 being capable of driving the propeller 11 to rotate to accelerate and pressurize the air flow after flowing through the first stage fuel cell stack 8, and the air flow accelerated and pressurized by the propeller 11 continues to flow into the second stage fuel cell stack 12 to provide oxygen required for the reaction of the cathode of the second stage fuel cell stack 12 and to cool the stack.

[0058] Further, the fuel cell driven aero-engine further comprises:

[0059] a controller 9 and a storage battery 13, the controller 9 being connected with the storage battery 13, the first driving motor 7 and the second driving motor 10, so that the controller 9 can supply power to the first driving motor 7 and the second driving motor 10 through the storage battery 13 after the controller 9 is connected with the storage battery 13.

[0060] Further, the controller 9 is also connected with the first stage fuel cell stack 8 and the second stage fuel cell stack 12, so that the controller 9 can supply power to the first driving motor 7 and the second driving motor 10 through the first stage fuel cell stack 8 and the second stage fuel cell stack 12.

[0061] As a preferred example of the present application, the aircraft engine system driven by fuel cells provided by the present application can also select the energy source of the first driving motor 7 and the second driving motor 10 according to the power requirement by the controller 9, thereby driving the ducted fan 1 to generate thrust and the first stage fuel cell stack 8 to generate airflow required, and driving the propeller 11 to provide the second stage fuel cell stack 12 with required airflow, so as to realize continuous operation.

[0062] 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 driving motor 7 and the second driving motor 10 to be powered by the first stage fuel cell stack 8 and the second stage fuel cell stack 12, while using 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 driving motor 7 and the second driving motor 10 to be powered by the first stage fuel cell stack 8, the second stage fuel cell stack 12 and the battery 13 working at the same time to meet the power requirement.

[0063] As some examples of the present application, the aircraft engine driven by fuel cells also includes a plurality of fixing frames for mounting fuel cell stacks, such as the first stage fuel cell stack 8, the second stage fuel cell stack 12 and the like.

[0064] Specifically, the fixing frame includes:

[0065] The first stage fixing frame 3 is used to mount and fix the first stage fuel cell stack 8, and the second stage fixing frame 5 is used to mount and fix the second stage fuel cell stack 12.

[0066] Preferably, as shown in Figures 4-5 The first stage fixing frame 3 and the second stage fixing frame 5 include an annular wall and a mounting frame mounted in the annular wall, the annular wall can be used to connect with the fairing described below, and the mounting frame is used to connect with the fuel cell stack, and the specific shape and structure of the mounting frame can be set according to the needs of mounting the fuel cell stack.

[0067] As some examples of the present application, the aircraft engine driven by fuel cells also includes a plurality of fairings, which are arranged around the periphery of the first stage fuel cell stack 8 and the second stage fuel cell stack 12, and are used to guide the airflow entering the first stage fuel cell stack 8 and the second stage fuel cell stack 12.

[0068] Specifically, the fairing includes:

[0069] The first section fairing 2 is fixed on the first stage fixing frame 3 by connecting members such as bolts, and is used to guide the air flow through the center of the ducted fan 1 into the first section fairing 2, and to provide the gas required for the reaction and cooling of the cathode of the first stage fuel cell stack 8;

[0070] The second section fairing 4 is fixed between the first stage fixing frame 3 and the second stage fixing frame 5 by connecting members such as bolts, and is used to guide the air flow through the cathode of the first stage fuel cell stack 8 into the propeller 11, and to provide the gas required for the reaction and cooling of the cathode of the second stage fuel cell stack 12;

[0071] The third section fairing 6 is fixed on the second stage fixing frame 5 by connecting members such as bolts, and is used to guide the air flow through the cathode of the second stage fuel cell stack 12 out of the engine, and to provide a small part of the thrust.

[0072] Preferably, from the front end to the rear end of the engine, the cross section of the first section fairing 2 gradually expands along the main axis of the engine, the cross section of the second section fairing 4 is cylindrical and does not change along the main axis of the engine, and the cross section of the third section fairing 6 gradually shrinks along the main axis of the engine.

[0073] In addition, the connection between other components in the fuel cell driven aero-engine is described as follows:

[0074] The ducted fan 1 is fixed on the motor shaft of the first driving motor 7 and is driven by the first driving motor 7 to generate thrust and achieve propulsion, and to provide the gas required for the reaction and cooling of the cathode of the fuel cell stack;

[0075] The first driving motor 7 is fixed at the front end of the first stage fixing frame 3 by connecting members such as bolts, and is used to drive the rotation of the ducted fan 1;

[0076] The front and rear ends of the center of the first stage fixing frame 3 are connected with the first driving motor 7 and the second driving motor 10 respectively by connecting members such as bolts, and are used to fix the first driving motor 7 and the second driving motor 10; the front and rear ends of the edge of the annular wall are connected with the first section fairing 2 and the second section fairing 4 respectively by connecting members such as bolts, and are used to fix the first section fairing 2 and the second section fairing 4; the middle of the annular wall is connected with the first stage fuel cell stack 8 by connecting members such as bolts, and is used to fix the first stage fuel cell stack 8;

[0077] 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, and is used to provide power for driving the first driving motor 7 and the second driving motor 10 to work continuously;

[0078] The second driving motor 10 is fixed at the rear end of the center of the first stage fixing frame 3 by connecting members such as bolts, 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;

[0079] The propeller 11 is fixed on the motor shaft of the second driving motor 10 and is driven by the second driving motor 10, which is used to accelerate and pressurize the gas flowing through the cathode of the first stage fuel cell stack 8, so that the gas flowing through the first stage fuel cell stack 8 can quickly flow into the second stage fuel cell stack 12;

[0080] The second stage fixing frame 5 is connected with the second section of the fairing 4 and the third section of the fairing 6 at the front and rear ends respectively by fixing members such as bolts, and is used to fix the second section of the fairing 4 and the third section of the fairing 6. The middle of the annular wall is connected with the second stage fuel cell stack 12 by connecting members such as bolts, and is used to fix the second stage fuel cell stack 12;

[0081] The second stage fuel cell stack 12 is fixed on the second stage fixing frame 5 by connecting members such as bolts, and outputs electric energy under the reaction of fuel and air, which is used to provide part of the power supply for the continuous operation of the first driving motor 7 and the second driving motor 10;

[0082] The controller 9 is fixed at the middle gap of the first stage fuel cell stack 8, and is used to monitor the working state of the battery 13, the first stage fuel cell stack 8 and the second stage fuel cell stack 12, as well as the energy direction of the battery 13, the first stage fuel cell stack 8 and the second stage fuel cell stack 12;

[0083] The battery 13 is fixed at the middle gap of the second stage fuel cell stack 12, and is used to provide power supply when the engine starts, and when the power demand of the engine is greater than the maximum power provided by the first stage fuel cell stack 8 and the second stage fuel cell stack 12, 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 for the first driving motor 7 and the second driving motor 10.

[0084] Preferably, the ducted fan 1 is a metal fan.

[0085] Preferably, the materials of the first section of the fairing 2, the second section of the fairing 4 and the third section of the fairing 6 are epoxy resin or carbon fiber with light weight, high strength and high rigidity.

[0086] Preferably, the materials of the first stage fixing frame 3 and the second stage fixing frame 5 are alloy steel or titanium alloy with high strength, good toughness and excellent welding performance, and the connection mode between the first stage fixing frame 3 and the second stage fixing frame 5 and the body and the fairing is welding or bolt connection.

[0087] Preferably, the first driving motor 7 and the second driving motor 10 are high-power permanent magnet synchronous motors or brushless direct current motors.

[0088] Preferably, the first fuel cell stack 8 and the second 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 for supplying methanol to the two fuel cell stacks.

[0089] Preferably, the propeller 11 is a carbon fiber propeller, a wooden propeller or a composite material propeller.

[0090] Preferably, the storage battery 13 is a secondary battery such as a lithium battery.

[0091] Preferably, the first fuel cell stack 8 is installed on the first fixed frame 3, and the flow direction of the cathode flow channel in the first fuel cell stack 8 is parallel to the flight direction. On the front and rear sides of the first fixed frame 3, the first driving motor 7 and the second driving motor 10 are respectively installed in parallel to the flow direction of the cathode flow channel of the first fuel cell stack 8. The first driving motor 7 is installed at the front end of the first fuel cell stack 8, and the motor shaft is oriented in the same direction as the flight direction. The ducted fan 1 is installed on the motor shaft of the first driving motor 7, and is used to mainly provide the thrust required by the engine. The second driving motor 10 is installed at the rear end of the first fuel cell stack 8, and the motor shaft is oriented in the opposite direction of the flight direction. The propeller 11 is installed on the motor shaft of the second driving motor 10. The second fuel cell stack 12 is installed on the second fixed frame 5, and the second fixed frame 5 and the second fuel cell stack 12 are installed at the rear end of the second driving motor 10. The first section of the fairing 2, the second section of the fairing 4 and the third section of the fairing 6 are respectively installed between the first fixed frame 6 and the ducted fan 1, between the first fixed frame 3 and the second fixed frame 5, and at the rear end of the second fixed frame 5, and together with the fixed frames form a relatively closed inner duct area, which is used to guide part of the air flow after passing through the ducted fan 1 into the two fuel cell stacks, and to discharge the exhaust gas after passing through the two fuel cell stacks. The fuel source of the hydrogen supply system is installed inside the aircraft, and the fuel is introduced into the fuel cell stacks through the fuel inlet arranged beside the first fuel cell stack 8 and the second fuel cell stack 12, and is discharged through the fuel outlet. The storage battery 13 is installed at the center of the second fuel cell stack 12 on the engine axis, and is connected with the controller 9. The controller 9 is installed at the center of the first fuel cell stack 8 on the engine axis, and can monitor the working state of the fuel cell stacks and the storage battery 13, and control the switch of the fuel supply system.

[0092] As some examples of the present application, the fuel cell driven aero-engine further comprises: a third fuel cell stack, a fourth fuel cell stack, a fifth fuel cell stack, and so on, which are arranged behind the second fuel cell stack 12, wherein n≥2, preferably n≥3, the gas flow discharged from the second fuel cell stack 12 enters the third fuel cell stack, the fourth fuel cell stack, the fifth fuel cell stack, and so on, in sequence, and provides oxygen required for the reaction of the cathode and cools the stack.

[0093] Further, the third fuel cell stack, the fourth fuel cell stack, the fifth fuel cell stack, and so on, are provided with corresponding auxiliary driving motors and auxiliary propellers, the auxiliary driving motors can drive the auxiliary propellers connected therewith to rotate, and the gas flow passing through the previous fuel cell stack is accelerated and pressurized by the auxiliary propellers and then flows into the next fuel cell stack.

[0094] The fuel cell stack structure of the fuel cell driven aero-engine of the present application is not limited to two levels, and the number of stack levels can be increased after the second fuel cell stack 12 according to the power requirement, and the necessary auxiliary motors and auxiliary propellers are provided to improve the overall output power of the engine and meet greater power requirements.

[0095] Therefore, it can be understood that the third fuel cell stack, the fourth fuel cell stack, the fifth fuel cell stack, and so on, can be regarded as a repeated unit of the second fuel cell stack 12, and the structure, configuration, and connection mode between the third fuel cell stack, the fourth fuel cell stack, the fifth fuel cell stack, and so on, and other components can be referred to the second fuel cell stack 12.

[0096] The working principle of the fuel cell driven engine of the present application is described by taking the structure comprising two-stage fuel cell stacks as an example. First, the controller 9 turns on the battery 13 to supply power to the first driving motor 7 and the second driving motor 10, and the first driving motor 7 and the second driving motor 10 work and 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 fairing 2, 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 in the second section of the fairing 4, and the propeller 11 driven by the second driving motor 10 accelerates and pressurizes again, and then flows into the second-stage fuel cell stack 12 to provide the required air for the reaction and cooling of the cathode of the second-stage fuel cell stack 12, and finally accelerates and discharges through the outlet of the third section of the fairing 6 to provide a small part of the supplemental thrust for the engine. At the same time, the hydrogen supply system provides the required fuel for the anode of the stack from the fuel inlet of the two-stage fuel cell stack, and the two-stage fuel cell stack group starts to operate to output electric power, and the controller 9 switches the energy source of each driving motor to the fuel cell. Thereafter, the engine can select the energy source of the first driving motor 7 and the second driving motor 10 according to the power requirement by the controller 9 to drive the ducted fan 1 to generate thrust and the required airflow of the first-stage fuel cell stack 8, and drive the propeller 11 to provide the required airflow of the second-stage fuel cell stack 12 to realize continuous operation. When the required power of 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 for the engine; when the required power of 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 for the engine, and uses the excess power to charge the battery 13, so as to realize the continuous operation of the engine in various working states.

[0097] The application provides an aircraft engine driven by a fuel cell, which abandons the simple series working mode of a traditional electric propulsion power system, and adopts a fusion design in structure and thermodynamics, so that the fuel cell and the engine structure are fused. On one hand, the air supply system and the cooling system of the traditional fuel cell system are abandoned, and the air flow generated by the ducted fan 1 and the propeller 11 is directly used to realize the supply of the cathode air of the fuel cell and the cooling of the stack; on the other hand, for a larger power, such as a fuel cell aviation propulsion system with a power greater than 5 kW, water cooling and the like need to be used for cooling, so that the cooling components are heavy, the system structure is complex, and the power-to-weight ratio is low. Through the distributed arrangement of the two-stage fuel cell stack structure, the air-cooled cooling mode can still be used under the condition of a larger power demand, the air-cooled cooling mode of the larger power fuel cell aviation propulsion system is realized, the structural efficiency and the power-to-weight ratio of the larger power engine are greatly improved, and meanwhile, the distributed stack arrangement form can make the power design of the fuel cell aviation propulsion system more flexible, different power demands can be met, and the application of the fuel cell in the aviation propulsion system is facilitated.

[0098] In addition, only the three types of rotating components of the ducted fan 1, the propeller 11 and the driving motor are contained in the aircraft engine driven by the fuel cell, so that the aircraft engine has the advantage of low noise compared with the traditional aircraft engine. Meanwhile, the aircraft propulsion system is all-electric, there is no fuel combustion process, the working temperature of the whole machine is low, and the infrared stealth performance is good; the product of the fuel reaction chemical process involved in the application is water, the exhaust product is residual fuel and oxygen, and various nitrogen oxides of the traditional aircraft engine are not contained, so that the aircraft engine is zero emission, pollution-free and environment-friendly.

[0099] In conclusion, the aircraft engine driven by the fuel cell has the following advantages:

[0100] (1) The present application fuses the fuel cell with the traditional aero-engine structure, on the one hand, the air supply system in the original fuel cell system is abandoned, the airflow after the ducted fan and the propeller is directly used to provide the air required for the cathode of the fuel cell for reaction and cooling, which can improve the structural efficiency of the whole system and the power-to-weight ratio of the whole machine; on the other hand, aiming at the problem that the complex cooling mode such as water cooling needs to be used when the engine power is large, resulting in low power-to-weight ratio of the system, a distributed fuel cell arrangement mode is adopted, which can greatly improve the power-to-weight ratio of the system for the fuel cell aviation propulsion system with large power. In addition, the present application only has three rotating parts of the ducted fan, the propeller and the driving motor, which has the advantage of low noise compared with the traditional aero-engine; at the same time, the present application is an all-electric aviation propulsion system, there is no fuel combustion process, the working temperature of the whole machine is low, and the infrared stealth performance is good; and the product of the fuel reaction chemical process involved in the present application is water, the exhaust product is residual fuel and oxygen, and there is no various nitrogen oxides of the traditional aero-engine, so it is zero emission, pollution-free and friendly to the environment.

[0101] (2) The first section of the fairing of the present application gradually expands rearward in cross section, which can reduce the speed of the airflow behind the ducted fan, increase the pressure and temperature of the airflow, and is beneficial to the further flow of the airflow into the fuel cell for reaction; the third section of the fairing gradually contracts rearward in cross section, which can improve the speed of the airflow behind the second fuel cell, and is beneficial to improving the additional thrust generated after the airflow flows out of the fairing.

[0102] (3) The airflow flowing through the ducted fan and entering the inner duct can be heated by the heat generated by the driving motor, the controller and other components after flowing through the first and second driving motors and the controller, so as to reduce the influence of the too low temperature of the gas flow under the aviation flight condition on the performance of the fuel cell stack.

[0103] (4) The fuel cell stack in the present application adopts a graphite stack or a metal stack, which is light in quality and high in power-to-weight ratio.

[0104] (5) The fuel used in the fuel cell stack in the present application is hydrogen, and the only electrochemical reaction product is water, which has the advantages of being clean and pollution-free.

[0105] (6) The propeller in the present application is selected from carbon fiber propeller, wooden propeller or composite material propeller, which is light in quality and good in aerodynamic performance.

[0106] (7) The driving motor in the present application is selected from permanent magnet synchronous motor or brushless direct current motor, which has large torque, high power density and high efficiency.

[0107] (8) The two-stage fixing frame in the present application is made of alloy steel or titanium alloy, which has high strength and good toughness.

[0108] (9) The three-section flow guide cover in the application is made of epoxy resin or carbon fiber material, which is light in weight, high in strength and rigidity.

[0109] (10) The aircraft engine driven by the fuel cell in the application adopts a distributed electric pile arrangement form, after the second-stage fuel cell electric pile in the example, the number of electric pile stages can be increased according to the same configuration of the second-stage fuel cell electric pile, and necessary auxiliary motors and auxiliary propellers are equipped, so that the power design of the fuel cell aviation propulsion system is more flexible, and different power requirements can be met.

[0110] The embodiments of the application are described above in combination with the drawings, the embodiments in the application and the features in the embodiments can be combined with each other without conflict, the application is not limited to the above specific embodiments, the above specific embodiments are only illustrative but not restrictive, and those skilled in the art can make many forms under the inspiration of the application without departing from the purpose of the application and the scope protected by the claims, which all belong to the protection of the application.

Claims

1. An aircraft engine driven by a fuel cell, characterized in that, Comprise: A first drive motor (7), A ducted fan (1), A first stage fuel cell stack (8), A second stage fuel cell stack (12), And a hydrogen supply system, The first drive motor (7) drives the rotation of the ducted fan (1) to generate airflow, most of which is directly discharged backward to generate main thrust; a small part of the airflow first enters the first stage fuel cell stack (8) to provide the oxygen required for the reaction of the cathode of the first stage fuel cell stack (8) and cool the stack, and then flows into the second stage fuel cell stack (12) to provide the oxygen required for the reaction of the cathode of the second stage fuel cell stack (12) and cool the stack; at the same time, the hydrogen supply system provides the hydrogen required for the reaction of the anode of the first stage fuel cell stack (8) and the second stage fuel cell stack (12) respectively; The fuel cell driven aero-engine further comprises: A second drive motor (10) and a propeller (11), 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 rotation of the propeller (11) to accelerate and pressurize 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) to provide the oxygen required for the reaction of the cathode of the second stage fuel cell stack (12) and cool the stack; A controller (9) and a battery (13), the controller (9) is connected with 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 the controller (9) is connected with the battery (13); The controller (9) is also connected with 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).

2. The fuel cell driven aero-engine according to claim 1, wherein The controller (9) is installed at the gap in the middle of the first stage fuel cell stack (8), and the battery (13) is installed at the gap in the middle of the second stage fuel cell stack (12).

3. The aircraft engine driven by fuel cell according to claim 1, characterized in that, The fuel cell driven aero-engine selects the energy source of the first drive motor (7) and the second drive motor (10) by the controller (9) according to the power demand: When the demand 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 to supply power to the first drive motor (7) and the second drive motor (10) by the first stage fuel cell stack (8) and the second stage fuel cell stack (12), and charges the battery (13) with the surplus power until it is full. When the demand power is greater than the maximum power of the first fuel cell stack (8) and the second fuel cell stack (12), the controller (9) selects to supply power to the first drive motor (7) and the second drive motor (10) by the first fuel cell stack (8), the second fuel cell stack (12) and the battery (13) working at the same time.

4. The aircraft engine driven by fuel cell according to claim 1, characterized in that, The fuel cell driven aero-engine further comprises a multi-section fairing, which is arranged around the periphery of the first fuel cell stack (8) and the second fuel cell stack (12) and is used for guiding the airflow into the first fuel cell stack (8) and the second fuel cell stack (12).

5. The aircraft engine driven by fuel cell according to claim 4, characterized in that, The fairing comprises: a first section fairing (2) for guiding the airflow through the center of the ducted fan (1) into the first section fairing (2) to provide the gas required for reaction and cooling of the cathode of the first fuel cell stack (8); a second section fairing (4) for guiding the airflow through the cathode of the first fuel cell stack (8) into the propeller (11) to provide the gas required for reaction and cooling of the cathode of the second fuel cell stack (12); a third section fairing (6) for guiding the airflow through the cathode of the second fuel cell stack (12) out of the engine and providing a part of the thrust.

6. The aircraft engine driven by fuel cell according to claim 5, characterized in that, From the front end to the rear end of the engine, the cross section of the first section fairing (2) gradually expands along the main axis of the engine, the cross section of the second section fairing (4) is cylindrical and does not change along the main axis of the engine, and the cross section of the third section fairing (6) gradually contracts along the main axis of the engine.

7. The aircraft engine driven by fuel cell according to claim 1, characterized in that, The fuel cell driven aero-engine further comprises a third fuel cell stack, …, an n-th fuel cell stack arranged at the rear end of the second fuel cell stack (12), wherein n≥2, the airflow discharged from the second fuel cell stack (12) enters the third fuel cell stack, …, the n-th fuel cell stack in turn to provide the oxygen required for reaction and cooling of the cathode of the third fuel cell stack, …, the n-th fuel cell stack.

8. The aircraft engine driven by fuel cell according to claim 7, characterized in that, The third fuel cell stack, …, the n-th fuel cell stack are provided with corresponding auxiliary drive motors and auxiliary propellers, the auxiliary drive motor can drive the auxiliary propeller connected thereto to rotate, and the airflow through the previous fuel cell stack is accelerated and pressurized by the auxiliary propeller and then flows into the next fuel cell stack.

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