A fuel cell-liquid rocket combined power system and control method suitable for cruise missile multi-mode operation

Abstract

The application is a fuel cell-liquid rocket combined power system and control method suitable for multi-mode operation of a cruise missile. The application relates to the technical field of cruise missile power system design. The system of the application takes a hydrogen fuel cell as a core power source, and combines the design of a liquid rocket engine thrust chamber to realize the collaborative work of electric propulsion and chemical propulsion, effectively solving the problems of weak terminal acceleration ability, poor maneuverability and easy interception caused by low flight speed and insufficient thrust of the traditional electric propulsion scheme. The application can quickly switch between the cruise mode, high-speed attack mode and attitude control mode, providing matched power output for the cruise missile in different task stages. The power system of the application can provide power support for the cruise missile with low infrared characteristics, long endurance, high maneuvering penetration and flight attitude control capability.

Description

Technical Field

[0001] This invention relates to the field of loitering munition propulsion system design technology, and is a fuel cell-liquid rocket combined propulsion system and control method suitable for multi-modal operation of loitering munitions. Background Technology

[0002] Loitering munitions are a new type of smart munition that combines reconnaissance and strike capabilities. They have demonstrated high combat effectiveness in recent local conflicts, influencing combat styles. Therefore, low-cost, high-efficiency loitering munitions have significant application value and are one of the important directions for future weapons development. Cruise duration is a crucial indicator of loitering munition performance. Existing loitering munition propulsion systems mainly include turbojet engines, piston engines, and electric propulsion. Compared to other propulsion methods, electric propulsion offers advantages such as high energy conversion efficiency, compact system structure, low noise, and long cruise time. Furthermore, electric motors provide rapid response and good control performance, gradually becoming an important development direction for loitering munition propulsion systems. Further, fuel cells have a higher specific energy than traditional lithium batteries, providing a feasible way to extend the endurance of loitering munitions. Chinese patent application CN 121520096 A discloses a propulsion system for a multi-mode loitering munition, employing a combination of a fuel cell and a solid-liquid rocket. A solid propellant grain is placed in the combustion chamber, generating thrust through the spontaneous combustion of hydrogen peroxide and the propellant grain. However, this approach still has the following shortcomings: solid propellant grains make it difficult to achieve precise thrust adjustment and multiple start-stop cycles; the system integration is low, with the fuel cell and rocket propulsion system being relatively independent, failing to fully realize the sharing of fuel and oxidizer. To address these issues, this invention proposes a multi-modal propulsion system that utilizes a liquid rocket thrust chamber and a gas generator in tandem. By eliminating solid propellant grains, continuous thrust adjustment and multiple start-stop cycles are achieved, and the gas generator enables the dual utilization of hydrogen peroxide, thereby significantly improving system integration and energy efficiency. This provides a propulsion solution for loitering munitions that combines long-endurance cruise and high-maneuverability strike capabilities.

[0003] However, while electric propulsion systems are highly efficient, they offer relatively low sustained thrust and cruise speed; existing electric-propelled loitering munitions generally have speeds below 200 km / h. This results in poor maneuverability and terminal attack capabilities, making them vulnerable to interception and impacting their combat value. Rocket engines, on the other hand, offer high thrust, enhancing the acceleration of loitering munitions, but their limited range limits mean they are typically used as boosters during the launch phase of ground-based loitering munitions. Therefore, a single propulsion method is unsuitable as an ideal power solution for loitering munitions. Summary of the Invention

[0004] To improve the overall performance of loitering munitions, this invention discloses a fuel cell-liquid rocket combined propulsion system and control method suitable for multi-modal operation of loitering munitions. This invention combines a liquid rocket engine with a fuel cell system to design a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions. By rationally selecting fuels and oxidizers and optimizing the system design, the overall performance of the loitering munition is improved.

[0005] This invention provides the following technical solutions: A fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions, the system comprising: a hydrogen supply subsystem, a hydrogen peroxide supply subsystem, a fuel cell subsystem, a thrust chamber subsystem, and a gas generator subsystem; The fuel cell subsystem includes a fuel cell, a compressor, a first motor, a second motor, a heat exchanger, a propeller, and a hydrogen recovery device. The hydrogen supply subsystem is connected to the anode of the fuel cell, the fuel cell is connected to the second motor, the second motor is connected to the propeller, the heat exchanger is connected to the fuel cell, the outlet of the fuel cell anode flow channel is connected to the hydrogen recovery device, the first motor is connected to the compressor, and the compressor is connected to the inlet of the fuel cell cathode flow channel, forming the fuel cell oxidant supply flow path. The thrust chamber subsystem is a liquid rocket thrust chamber, including a combustion chamber, a Laval nozzle, and a nozzle. There is no solid propellant in the combustion chamber, and the nozzle is built into the combustion chamber. The combustion chamber is connected to the Laval nozzle, and hydrogen and hydrogen peroxide are directly combusted in the combustion chamber to generate thrust. The gas generator subsystem includes a gas generator, a turbopump, and a dehumidifier. The gas generator connects the turbopump and the dehumidifier. The hydrogen peroxide supply subsystem has two supply lines. The first supply line decomposes hydrogen peroxide through the gas generator to produce high-temperature, high-pressure gas that drives the turbopump. The exhaust gas after power is delivered is connected to the cathode of the fuel cell via the dehumidifier. The second supply line connects the turbopump to the nozzle. The thrust chamber subsystem adopts a liquid rocket thrust chamber. The gas generator subsystem simultaneously pressurizes the thrust chamber and supplies oxygen to the fuel cell.

[0006] Preferably, the system further includes: a hydrogen tank, a pressure reducing valve, a first valve, and a third valve; The hydrogen tank outlet is connected to a pressure reducing valve, which is connected to the fuel cell anode flow channel and nozzle through a first valve and a third valve, respectively, thus forming the fuel cell hydrogen supply flow path and the combustion chamber hydrogen supply flow path.

[0007] Preferably, the system further includes: a hydrogen peroxide tank and a second valve; The outlet of the hydrogen peroxide tank is connected to the second valve, which in turn connects to the gas generator, dehumidifier, and cathode channel of the fuel cell to form the fuel cell oxidant replenishment supply path; the hydrogen peroxide tank is connected to the second valve and then connected to the nozzle via a turbopump to form the combustion chamber oxidant supply path.

[0008] Preferably, the oxidant and fuel carried by the power system are high-pressure hydrogen and liquid hydrogen peroxide, respectively.

[0009] Preferably, the fuel cell is a proton exchange membrane fuel cell, which powers the motor to drive the propeller and generate thrust; The thrust chamber subsystem uses the rocket thrust chamber to generate thrust.

[0010] Preferably, the gas generator produces high-temperature, high-pressure gas by decomposing hydrogen peroxide to drive a turbopump, thereby pressurizing the hydrogen peroxide in the combustion chamber. The exhaust gas from the gas generator after it has done work is dehumidified by a dehumidifier and then introduced into the cathode of the fuel cell.

[0011] Preferably, the oxidant introduced into the cathode of the fuel cell is air or pure oxygen.

[0012] A control method for a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions, the method specifically comprising: When the loitering munition is conducting reconnaissance at a speed of 30 m / s, the fuel cell generates electricity and initiates the cruise mode; the pressure relief valve and the first valve are opened, and the second valve and the third valve are closed. The first motor drives the compressor, and hydrogen and air are introduced into the fuel cell to start generating electricity. Thrust is generated through the second motor and the propeller. Unused hydrogen is recycled and reused through the hydrogen recovery device of the fuel cell. Excess air is discharged from the system, and the heat exchanger removes the heat generated by the fuel cell. The cooling medium is air. When the loitering munition detects and locks onto a target, it switches to attack mode: the thrust chamber accelerates the loitering munition to a final velocity of over 200 m / s; the pressure reducing valve, the second valve, and the third valve are opened, and the first valve is closed. Some of the hydrogen peroxide enters the gas generator and decomposes to produce high-temperature, high-pressure gas that drives the turbopump to pressurize the remaining hydrogen peroxide. The hydrogen and the pressurized hydrogen peroxide are injected into the combustion chamber for combustion. The combustion gas does work through the Laval nozzle to generate a large thrust, which accelerates the loitering munition. When the loitering munition encounters airflow disturbance during its cruise, it switches to attitude control mode: opening the pressure relief valve, the first valve, the second valve, and the third valve, hydrogen peroxide is converted into pure oxygen after passing through the gas generator and dehumidifier, and then introduced into the cathode of the fuel cell to increase power. At the same time, some of the hydrogen peroxide is pressurized and introduced into the combustion chamber for combustion, and the gas is ejected through the Laval nozzle to increase thrust and control the attitude of the loitering munition.

[0013] A computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a control method for a fuel cell-liquid rocket combined propulsion system suitable for multimodal operation of a loitering munition.

[0014] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement a control method for a fuel cell-liquid rocket combined propulsion system suitable for multimodal operation of a loitering munition.

[0015] The present invention has the following beneficial effects: This invention proposes a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions. Addressing the problems of low thrust and speed limitations in existing electric propulsion systems, resulting in poor maneuverability and weak terminal penetration capabilities, it constructs a multi-modal propulsion architecture that combines electric propulsion, liquid rocket propulsion, and coordinated control. In cruise mode, a proton exchange membrane fuel cell drives a propeller for propulsion. Compared to traditional piston engines or jet propulsion, it eliminates the high-temperature combustion process and has a low exhaust temperature, significantly reducing infrared radiation signature and thus improving the loitering munition's stealth and survivability, while also offering advantages such as high energy density and long endurance. In high-speed strike mode, the rocket thrust chamber provides high instantaneous thrust for rapid acceleration, significantly enhancing terminal penetration capabilities. In attitude control mode, the fuel cell and thrust chamber work together to control the loitering munition's flight attitude. Through the coupling of multiple propulsion forms and rapid mode switching, this invention achieves a balance between low-infrared stealth cruise and high-maneuverability penetration capabilities, providing a propulsion system solution for loitering munitions that combines stealth, long endurance, and high thrust output.

[0016] This invention proposes a fuel cell-liquid rocket combined propulsion system suitable for multi-mode operation of loitering munitions. In cruise mode, the fuel cell system operates independently, consuming only air and not hydrogen peroxide. The fuel cell operates within its high-efficiency range, maximizing the loitering munition's endurance. When encountering sudden airflow disturbances, a gas generator provides pure oxygen to the fuel cell, briefly increasing its output power. The thrust chamber simultaneously activates, providing additional thrust to compensate for the fuel cell's poor transient response and improve the propulsion system's self-regulation capability in the face of sudden airflow interference. In strike mode, the thrust chamber operates independently, improving the loitering munition's maneuverability during terminal penetration and enabling it to engage targets with higher speeds, thus expanding the strike range of conventional electric propulsion systems. Through the coordination and switching between cruise, strike, and attitude control modes, this system achieves a unified capability for long-endurance reconnaissance, high-speed penetration, and stable flight attitude, comprehensively enhancing the loitering munition's mission adaptability.

[0017] This invention proposes a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions. It incorporates in-depth considerations regarding oxidizer, fuel selection, and propulsion system design. The "hydrogen-hydrogen peroxide" scheme allows the fuel cell and thrust chamber to share the same fuel and oxidizer, simplifying the overall structure and making the propulsion system more rational and compact. A gas generator simultaneously supplies oxygen to the fuel cell and pressurizes the oxidizer in the thrust chamber. Furthermore, by incorporating a hydrogen recovery device, unreacted hydrogen from the fuel cell anode is recycled and reused, further improving fuel efficiency and system economy.

[0018] Compared to existing technologies that use solid rockets, this invention uses a liquid rocket thrust chamber, eliminating the need for solid propellant grains, and achieving precise thrust adjustment and multiple start-stop capabilities. At the same time, the decomposition products of hydrogen peroxide are used by a gas generator to drive the turbopump and supply oxygen to the fuel cell, significantly improving system integration and energy utilization efficiency. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 The diagram shows a schematic of a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of a loitering munition, according to the present invention. Figure 2 The diagram shown is a schematic representation of the operation of the cruise mode propulsion system of the present invention. Figure 3 The diagram shown is a schematic diagram of the operation of the strike mode dynamic system described in this invention. Figure 4 The diagram shown is a schematic diagram of the operation of the attitude control modal dynamic system described in this invention.

[0021] Among them, 1-hydrogen tank, 2-pressure reducing valve, 3-first valve, 4-fuel cell, 5-heat exchanger, 6-compressor, 7-first motor, 8-hydrogen recovery device, 9-third valve, 10-hydrogen peroxide tank, 11-second valve, 12-turbo pump, 13-gas generator, 14-nozzle, 15-combustion chamber, 16-Laval nozzle, 17-second motor, 18-propeller, 19-dehumidifier. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The present invention will be described in detail below with reference to specific embodiments. Specific Implementation Example 1: according to Figures 1 to 4 As shown, the specific optimized technical solution adopted by the present invention to solve the above-mentioned technical problems is: The present invention relates to a fuel cell-liquid rocket combined power system and control method suitable for multi-modal operation of loitering munitions.

[0025] As attached Figure 1 As shown, this invention provides a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions, comprising a fuel cell subsystem, a thrust chamber subsystem, and a gas generator subsystem. The fuel cell subsystem includes a fuel cell hydrogen supply path consisting of a hydrogen tank 1, a pressure reducing valve 2, a first valve, an anode flow channel of a fuel cell 4, and a hydrogen recovery device 8; and an oxidant supply path consisting of a cathode flow channel of a fuel cell 4, a compressor 6, and a first motor 7. The electrical energy output from the fuel cell 4 is used to drive an electric propulsion device consisting of a second motor 17 and a propeller 18. The fuel cell subsystem also includes an air-cooled heat exchanger 5 for system heat dissipation. The thrust chamber subsystem includes a combustion chamber hydrogen supply path consisting of a hydrogen tank 1, a pressure reducing valve 2, and a third valve 9; a combustion chamber oxidant supply path consisting of a hydrogen peroxide tank 10, a second valve 11, and a turbopump 12; and a power unit consisting of a combustion chamber 15 and a Laval nozzle 16. The gas generator subsystem includes a gas generator 13 and a dehumidifier 19. The first valve 3 connects the pressure reducing valve 2 and the anode of the fuel cell 4. The second valve 11 connects the hydrogen peroxide tank 10, the turbopump 12, and the gas generator 13. The third valve 9 connects the pressure reducing valve 2 and the nozzle 14.

[0026] The core of the power system is that the fuel cell and thrust chamber share the same fuel and part of the oxidizer. The fuel is high-pressure hydrogen at 70 MPa, and the oxidizer is liquid hydrogen peroxide. The electric propulsion subsystem uses a proton exchange membrane fuel cell to power the motor and drive the propeller to generate thrust. The thrust chamber subsystem uses a combination of a combustion chamber and a Laval nozzle to generate thrust. Gas in the gas generator performs work to drive a turbopump, and the exhaust gas is dehumidified before being introduced into the cathode of the fuel cell.

[0027] This invention provides a control method for a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions: When loitering munitions are reconnaissance targets, their flight speed is 30 m / s, their flight status is stable, their power and thrust requirements are low, and their propulsion system is in cruise mode.

[0028] As shown in Figure 2, in cruise mode, the control system opens the first valve 3 and closes the second valve 11 and the third valve 9. Hydrogen in the hydrogen tank 1 is depressurized by the pressure reducing valve 2 and then transported to the anode of the fuel cell stack 4 through the first valve 3. Unreacted hydrogen is collected by the recovery device 8 and recirculated back into the anode of the fuel cell 4 to improve utilization. The first motor 7 drives the compressor 6 to compress outside air and send it to the cathode of the fuel cell 4. Unreacted air and generated water vapor are discharged through the exhaust path. Hydrogen and oxygen in the fuel cell 4 undergo an electrochemical reaction to generate electricity, powering the first motor 7 and the second motor 17. The second motor 17 drives the propeller 18 to generate cruise thrust. The heat generated during fuel cell operation is exchanged with outside cold air through the heat exchanger 5 to maintain the system at a suitable operating temperature. Through this method, the loitering munition uses the fuel cell as the main power source in cruise mode, achieving high-efficiency, low-noise, and stable long-term flight, thus significantly improving overall endurance.

[0029] After the loitering munition detects a target, it ends its cruise flight and begins to accelerate at full speed, causing a surge in thrust demand, and the propulsion system switches to strike mode.

[0030] As shown in Figure 3, in the high-speed impact mode, the control system opens the second valve 11 and the third valve 9, and closes the first valve 3. At this time, the hydrogen in the hydrogen tank 1 is delivered to the nozzle 14 through the third valve 9; the hydrogen peroxide in the hydrogen peroxide tank 10 enters the distribution circuit through the second valve 11, of which about 5% of the hydrogen peroxide is introduced into the gas generator 13 for catalytic decomposition. The high-temperature decomposition gas produced is used to drive the turbopump, so that the remaining hydrogen peroxide is pressurized to about 5.5 MPa under the action of the turbopump and delivered to the nozzle 14. The nozzle 14 injects hydrogen and pressurized hydrogen peroxide into the combustion chamber 15. The two diffuse in the combustion chamber and undergo a combustion reaction (2H2 + O2 → 2H2O), releasing about 120 MJ / kg of reaction heat, so that the combustion chamber temperature can reach above 2500 K and the combustion chamber pressure is about 5 MPa. High-temperature and high-pressure gas expands through the Laval nozzle 16 to form a high-speed jet, providing the loitering munition with a large instantaneous thrust, which increases its flight speed to over 200 m / s in a short time. This significantly enhances the loitering munition's maneuverability and terminal penetration capability, reduces the probability of being intercepted, and enables it to strike high-speed targets.

[0031] Loitering munitions are susceptible to sudden airflow disturbances during long-duration high-altitude cruises. When external disturbances disrupt the attitude stability of the munition, the cruise mode alone is insufficient to quickly restore flight balance. Therefore, this system incorporates an attitude control mode that rapidly increases thrust to quickly restore flight balance and trajectory stability.

[0032] As shown in Figure 4, in attitude control mode, the control system simultaneously opens the first valve 3, the second valve 11, and the third valve 9. After the gas generator is started, the first motor 7 and the compressor 6 stop working. The fuel cell system no longer introduces air from the outside, and all the oxygen required by the fuel cell cathode is provided by the gas generator. Hydrogen peroxide is transported to the gas generator 13 through the second valve 11 for catalytic decomposition. The generated high-temperature gas drives the turbopump 12 to work, and after the dehumidifier 19 removes water vapor and cools it to about 90°C, it is input as oxygen-enriched gas into the cathode of the fuel cell 4, so that the oxidant of the fuel cell is converted into pure oxygen to improve the battery output power. At the same time, the hydrogen peroxide pressurized by the turbopump 12 and the hydrogen gas transported through the third valve 9 enter the combustion chamber together, where a combustion reaction occurs to generate additional thrust. The electric propulsion provided by the fuel cell and the chemical propulsion generated by the thrust chamber work together to enable the loitering munition to obtain a significant thrust increase in a short time, thereby overcoming the shortcomings of the slow response speed of the fuel cell, effectively resisting sudden airflow disturbances and maintaining flight stability.

[0033] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a control method for a fuel cell-liquid rocket combined propulsion system suitable for multimodal operation of a loitering munition.

[0034] The present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a control method for a fuel cell-liquid rocket combined propulsion system suitable for multimodal operation of a loitering munition. Specific Implementation Example 2: To improve the overall performance of loitering munitions, this paper combines a liquid rocket engine with a fuel cell system to design a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions. By rationally selecting fuels and oxidizers and optimizing the system design, the overall performance of loitering munitions can be improved.

[0036] To achieve the above objectives, this invention designs the following loitering munition propulsion system technical solution: a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions, whose main subsystems include: a fuel cell subsystem, a thrust chamber subsystem, and a gas generator subsystem. The fuel cell subsystem includes: a fuel cell hydrogen supply path consisting of a hydrogen tank, a pressure reducing valve, a first valve, and a hydrogen recovery device; a fuel cell oxidant supply path consisting of a proton exchange membrane fuel cell, a compressor, and a first motor; and a drive device consisting of a second motor and a propeller, as well as an air-cooled heat exchanger. The thrust chamber subsystem is a liquid rocket thrust chamber, including a combustion chamber hydrogen supply path consisting of a hydrogen tank, a pressure reducing valve, and a third valve; a combustion chamber oxidant supply path consisting of a hydrogen peroxide tank, a second valve, a turbopump, and a nozzle; and a thrust chamber consisting of a combustion chamber and a Laval nozzle. There is no solid propellant in the combustion chamber; hydrogen and hydrogen peroxide are injected through the nozzle and directly combusted in the combustion chamber to generate thrust. The gas generator subsystem consists of a gas generator and a dehumidifier. The hydrogen tank outlet is connected to a pressure reducing valve, which is connected to the fuel cell inlet and nozzle via a first valve and a third valve, respectively, forming the fuel cell hydrogen supply path and the combustion chamber hydrogen supply path. The first motor is connected to the compressor, forming the air oxidant supply path under normal fuel cell operating conditions. The hydrogen peroxide tank outlet is connected to a second valve, which is sequentially connected to a gas generator, a dehumidifier, and the fuel cell cathode, forming the pure oxygen supplementation supply path for the fuel cell when a short-term power boost is required. The hydrogen peroxide tank is connected to the second valve and then connected to the nozzle via a turbopump, forming the combustion chamber oxidant supply path.

[0037] The fuel cell and the thrust chamber share the same fuel and some of the oxidant.

[0038] The power system carries high-pressure hydrogen and liquid hydrogen peroxide as oxidant and fuel.

[0039] The electric propulsion subsystem uses a proton exchange membrane fuel cell to power the second motor and drive the propeller to generate thrust.

[0040] The thrust chamber subsystem generates thrust using a combination of a combustion chamber and a Laval nozzle.

[0041] The gas generator produces high-temperature, high-pressure gas by decomposing hydrogen peroxide, which drives a turbine pump to pressurize the oxidant in the combustion chamber.

[0042] The exhaust gas from the gas generator after it has done its work is dehumidified by a dehumidifier and then introduced into the cathode of the fuel cell.

[0043] The oxidant introduced into the cathode of the fuel cell is either air or pure oxygen.

[0044] This invention also provides a control method for a fuel cell-liquid rocket combined propulsion system suitable for multi-mode operation of a loitering munition. When the loitering munition is conducting reconnaissance at a speed of 30 m / s, the fuel cell generates electricity, activating the cruise mode. Open the pressure reducing valve and the first valve, close the second valve and the third valve, the first motor drives the compressor, hydrogen and oxygen are introduced into the fuel cell, and power generation begins. The energy management module drives the second motor and the propeller to generate thrust. Unused hydrogen is recycled and reused through the fuel cell's hydrogen recovery device. Excess air is discharged from the system, and the heat exchanger removes the heat generated by the fuel cell's power generation. The cooling medium is air.

[0045] The present invention also provides a control method for a fuel cell-liquid rocket combined propulsion system suitable for multi-mode operation of loitering munitions. When the loitering munition detects and locks onto a target, it switches to attack mode, and the thrust chamber works to accelerate the loitering munition to a final velocity of 200 m / s.

[0046] The pressure reducing valve, the second valve, and the third valve are opened, while the first valve is closed. Approximately 5% of the hydrogen peroxide enters the gas generator, where it decomposes to produce high-temperature, high-pressure gas that drives the turbopump to pressurize the remaining hydrogen peroxide. The hydrogen and the pressurized hydrogen peroxide are then injected into the combustion chamber for combustion. The combustion gas passes through the Laval nozzle to perform work, generating a large thrust that ultimately accelerates the loitering munition.

[0047] The present invention also provides a method for using a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions. When the loitering munition encounters airflow disturbance during cruise, the loitering munition switches to attitude control mode.

[0048] By opening the pressure reducing valve, the first valve, the second valve, and the third valve, hydrogen peroxide is decomposed by the gas generator and then dehumidified to obtain pure oxygen, which is then introduced into the cathode of the fuel cell. At the same time, the compressor stops working, increasing the output power of the fuel cell. Meanwhile, some of the hydrogen peroxide is pressurized by the turbopump and then introduced into the combustion chamber for combustion, thereby increasing the thrust of the power system and controlling the attitude of the loitering munition.

[0049] In summary, the system of this invention uses a hydrogen fuel cell as its core power source and combines it with the thrust chamber design of a liquid rocket engine to achieve synergistic operation of electric and chemical propulsion. This effectively solves the problems of low flight speed and insufficient thrust in traditional electric propulsion schemes, resulting in weak terminal acceleration, poor maneuverability, and susceptibility to interception. The propulsion system has three modes: 1. Cruise mode, 2. High-speed strike mode, and 3. Attitude control mode. In cruise mode, the fuel cell drives the propeller, which features no high-temperature combustion process and low exhaust temperature, reducing infrared radiation signature and improving the stealth performance and survivability of the loitering munition. It also has advantages such as long endurance, high energy conversion efficiency, and low noise. In high-speed strike mode, the thrust chamber provides high instantaneous thrust output, significantly improving maneuverability and terminal penetration performance. In attitude control mode, the fuel cell and thrust chamber work together to control the flight attitude of the loitering munition. The propulsion system mainly includes a fuel cell subsystem, a thrust chamber subsystem, a gas generator subsystem, a hydrogen supply subsystem, and a hydrogen peroxide supply subsystem. It can rapidly switch between cruise mode, high-speed strike mode, and attitude control mode, providing matched power output for the loitering munition in different mission phases. This invention's propulsion system can provide the loitering munition with power support that combines low infrared signature, long endurance, high maneuverability for penetration, and flight attitude control capabilities.

[0050] The above description is merely a preferred embodiment of a fuel cell-liquid rocket combined propulsion system and control method suitable for multi-modal operation of loitering munitions. The scope of protection for a fuel cell-liquid rocket combined propulsion system and control method suitable for multi-modal operation of loitering munitions is not limited to the above embodiments; all technical solutions falling within this conceptual framework are within the protection scope of this invention. It should be noted that for those skilled in the art, any improvements and variations made without departing from the principles of this invention should also be considered within the protection scope of this invention.

Claims

1. A fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of loitering munitions, characterized in that: The system includes: a hydrogen supply subsystem, a hydrogen peroxide supply subsystem, a fuel cell subsystem, a thrust chamber subsystem, and a gas generator subsystem; The fuel cell subsystem includes a fuel cell, a compressor, a first motor, a second motor, a heat exchanger, a propeller, and a hydrogen recovery device. The hydrogen supply subsystem is connected to the anode of the fuel cell, the fuel cell is connected to the second motor, the second motor is connected to the propeller, the heat exchanger is connected to the fuel cell, the outlet of the fuel cell anode flow channel is connected to the hydrogen recovery device, the first motor is connected to the compressor, and the compressor is connected to the inlet of the fuel cell cathode flow channel, forming the fuel cell oxidant supply flow path. The thrust chamber subsystem is a liquid rocket thrust chamber, including a combustion chamber, a Laval nozzle, and a nozzle. There is no solid propellant in the combustion chamber, and the nozzle is built into the combustion chamber. The combustion chamber is connected to the Laval nozzle, and hydrogen and hydrogen peroxide are directly combusted in the combustion chamber to generate thrust. The gas generator subsystem includes a gas generator, a turbopump, and a dehumidifier. The gas generator connects the turbopump and the dehumidifier. The hydrogen peroxide supply subsystem has two supply lines. The first supply line decomposes hydrogen peroxide through the gas generator to produce high-temperature, high-pressure gas that drives the turbopump. The exhaust gas after power is delivered is connected to the cathode of the fuel cell via the dehumidifier. The second supply line connects the turbopump to the nozzle. The thrust chamber subsystem adopts a liquid rocket thrust chamber. The gas generator subsystem simultaneously pressurizes the thrust chamber and supplies oxygen to the fuel cell.

2. The system according to claim 1, characterized in that: The system also includes: a hydrogen tank, a pressure reducing valve, a first valve, and a third valve; The hydrogen tank outlet is connected to a pressure reducing valve, which is connected to the fuel cell anode flow channel and nozzle through a first valve and a third valve, respectively, thus forming the fuel cell hydrogen supply flow path and the combustion chamber hydrogen supply flow path.

3. The system according to claim 2, characterized in that: The system also includes: a hydrogen peroxide tank and a second valve; The outlet of the hydrogen peroxide tank is connected to the second valve, which in turn connects to the gas generator, dehumidifier, and cathode channel of the fuel cell to form the fuel cell oxidant replenishment supply path; the hydrogen peroxide tank is connected to the second valve and then connected to the nozzle via a turbopump to form the combustion chamber oxidant supply path.

4. The system according to claim 3, characterized in that: The power system carries high-pressure hydrogen and liquid hydrogen peroxide as oxidant and fuel, respectively.

5. The system according to claim 4, characterized in that: The fuel cell uses a proton exchange membrane fuel cell to power the motor and drive the propeller to generate thrust; the thrust chamber subsystem uses a rocket thrust chamber to generate thrust.

6. The system according to claim 5, characterized in that: The gas generator produces high-temperature, high-pressure gas by decomposing hydrogen peroxide, which drives a turbopump to pressurize the hydrogen peroxide in the combustion chamber. The exhaust gas after the gas generator has done work is dehumidified by a dehumidifier and then introduced into the cathode of the fuel cell.

7. The system according to claim 6, characterized in that: The oxidant introduced into the cathode of the fuel cell is air or pure oxygen.

8. A control method for a fuel cell-liquid rocket combined propulsion system suitable for multi-modal operation of a loitering munition, characterized in that: The method is specifically as follows: When the loitering munition is conducting reconnaissance at a speed of 30 m / s, the fuel cell generates electricity and initiates the cruise mode; the pressure relief valve and the first valve are opened, and the second valve and the third valve are closed. The first motor drives the compressor, and hydrogen and air are introduced into the fuel cell to start generating electricity. Thrust is generated through the second motor and the propeller. Unused hydrogen is recycled and reused through the hydrogen recovery device of the fuel cell. Excess air is discharged from the system, and the heat exchanger removes the heat generated by the fuel cell. The cooling medium is air. When the loitering munition detects and locks onto a target, it switches to attack mode: the thrust chamber accelerates the loitering munition to a final velocity of over 200 m / s; the pressure reducing valve, the second valve, and the third valve are opened, and the first valve is closed. Some of the hydrogen peroxide enters the gas generator and decomposes to produce high-temperature, high-pressure gas that drives the turbopump to pressurize the remaining hydrogen peroxide. The hydrogen and the pressurized hydrogen peroxide are injected into the combustion chamber for combustion. The combustion gas does work through the Laval nozzle to generate a large thrust, which accelerates the loitering munition. When the loitering munition encounters airflow disturbance during its cruise, it switches to attitude control mode: opening the pressure relief valve, the first valve, the second valve, and the third valve, hydrogen peroxide is converted into pure oxygen after passing through the gas generator and dehumidifier, and then introduced into the cathode of the fuel cell to increase power. At the same time, some of the hydrogen peroxide is pressurized and introduced into the combustion chamber for combustion, and the gas is ejected through the Laval nozzle to increase thrust and control the attitude of the loitering munition.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method as claimed in claim 8.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: The processor implements the method of claim 8 when executing the computer program.

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