A hydrogen fuel cell power plant airflow control method for transonic flight

Abstract

The application discloses a hydrogen fuel cell power device airflow control method for transonic flight and relates to the technical field of airflow control. The method is based on the provided hydrogen fuel cell power device, airflow is controlled through a split flow ring plate, an inner-bypass air intake valve and an outer-bypass air intake valve, dynamic matching between a power device airflow channel configuration and aerodynamic parameters is realized, the system can keep a stable working state within a wide-speed-domain wide-space-domain flight envelope, and the adaptability of the power device is improved while the structure is simplified and low emission is achieved.

Description

Technical Field

[0001] This invention relates to the field of airflow control technology, and more specifically to an airflow control method for a hydrogen fuel cell power unit used in transonic flight. Background Technology

[0002] Current aircraft propulsion systems primarily employ aero gas turbine engines. These engines generate high-temperature, high-pressure gas through the combustion of fuel and compressed air, driving the turbine output shaft to power the inner compressor and outer bypass fan. The exhaust gas then generates thrust through the tail nozzle. From a gas dynamics perspective, this type of propulsion system mainly relies on the combustion process to increase the total temperature and pressure of the gas, and then uses the inner compressor for pressurization and the nozzle for expansion to increase the gas momentum, thereby generating thrust. While this type of propulsion system can provide stable thrust over a relatively wide operating range, its energy acquisition depends on the heat released from fuel combustion. The system includes high-temperature components such as the combustion chamber and turbine, and requires careful matching with the compression components, resulting in a complex structure and high carbon emissions, making it difficult to meet the demands of green and low-carbon aviation development.

[0003] With the development of electric propulsion technology, hydrogen fuel cell-based aircraft power units have gradually attracted attention. Hydrogen fuel cells can use hydrogen and other energy sources as fuel to directly output electrical energy through electrochemical reactions, achieving a highly efficient conversion of chemical energy into electrical energy, and featuring low emissions and low exhaust temperature. Existing hydrogen fuel cell power units typically use electric motors to drive propellers or ducted fans to generate thrust. They mainly increase the exhaust velocity of the airflow through the fan, thereby generating a momentum difference between the inlet and outlet and thrust. However, they face the challenge of insufficient thrust during high-speed flight. Under subsonic flight conditions, this type of system has high propulsion efficiency; however, under transonic and supersonic flight conditions, the "hydrogen fuel cell + propeller or ducted fan" configuration has the following problems in terms of airflow organization and energy utilization: 1) At high speeds, the intake velocity of the power unit is high, and the fan / propeller is prone to generating shock waves, which leads to a decrease in aerodynamic efficiency. In addition, the exhaust velocity of the fan / propeller is insufficient due to insufficient pressure ratio, making it difficult to generate the inlet and outlet momentum difference and the required thrust; 2) At high altitudes, the atmosphere is thin, and the fan / propeller cannot provide the high-pressure air required for the chemical reaction of the hydrogen fuel cell due to insufficient pressure ratio, resulting in insufficient output power of the hydrogen fuel cell, which is difficult to match the power consumption required for the propeller / ducted fan to generate thrust.

[0004] Therefore, it is necessary to effectively control the internal airflow path distribution, aerodynamic parameter optimization, and dynamic matching of hydrogen fuel cell power generation and compression system power consumption from the perspective of airflow dynamics, so that the airflow can maintain reasonable aerodynamic parameter matching during distribution, compression, and nozzle expansion, thereby ensuring stable power supply from the hydrogen fuel cell while meeting the thrust requirements of the aircraft. Summary of the Invention

[0005] To address the shortcomings of the aforementioned background technology, this invention primarily solves the problems of insufficient high-pressure air supply and thrust in traditional hydrogen fuel cell power plants during transonic flight. This invention provides an airflow control method for hydrogen fuel cell power plants used in transonic flight. By coordinating the adjustment of the flow divider ring plate, the inner bleed air valve, and the outer bypass bleed air valve, this invention achieves reasonable control of airflow parameters of the power plant under different flight operating conditions.

[0006] To adapt to different flight speeds and altitudes, this invention proposes four airflow control modes: subsonic low-altitude, subsonic high-altitude, supersonic low-altitude, and supersonic high-altitude. By adjusting the splitter ring plate, the inner bleed valve, and the outer bleed valve, the airflow path and airflow parameters are dynamically reconfigured, thereby ensuring that the hydrogen fuel cell power unit obtains sufficient high-pressure air supply and adequate thrust under different flight conditions.

[0007] Through the above-mentioned airflow control method, the present invention realizes the distribution of airflow path, management of aerodynamic parameters, and dynamic matching of hydrogen fuel cell power generation and compression system power consumption under different flight conditions. This enables the power unit to maintain a stable working state within a wide speed and airspace flight range, ensuring a stable gas supply to the hydrogen fuel cell while meeting the thrust requirements of the aircraft, thereby improving the wide operating condition adaptability of the low-emission power unit.

[0008] The first objective of this invention is to provide a hydrogen fuel cell power unit for transonic flight, which provides power to the aircraft, including a duct, an outer bypass fan disposed at the front end of the duct, an inner compressor and a hydrogen fuel cell disposed within the duct, and a first drive mechanism for driving the outer bypass fan and a second drive mechanism for driving the inner compressor. The duct includes an inner duct and an outer duct; the inner compressor is disposed within the inner duct; A flow divider ring plate is provided at the front end of the duct between the inner duct and the outer duct. By adjusting the opening of the flow divider ring plate between the inner duct and the outer duct, the flow rate of air entering the inner duct and the outer duct can be controlled. The hydrogen fuel cell is placed in a cavity between the inner duct and the outer duct. An outer duct bleed valve is provided in the cavity on the front end of the hydrogen fuel cell near the outer duct. An inner duct bleed valve is provided in the cavity on the front end of the hydrogen fuel cell near the inner duct. An exhaust port is provided in the cavity on the rear end of the hydrogen fuel cell near the inner duct. Gas discharged from the exhaust port enters the tail nozzle. The inner duct bleed valve is located behind the inner compressor. The hydrogen fuel cell supplies power to the first drive mechanism and the second drive mechanism, respectively.

[0009] In one embodiment, a hydrogen storage mechanism for introducing hydrogen into a hydrogen fuel cell is also included.

[0010] In one embodiment, the air required for the hydrogen fuel cell is introduced into the gas flow of the hydrogen fuel cell through an external bleed valve and / or an internal bleed valve.

[0011] A second objective of this invention is to provide an airflow control method for a hydrogen fuel cell power plant used in transonic flight, comprising: Determine the flight Mach number and air resistance based on the aircraft's flight conditions; The total thrust under this flight condition is obtained based on air resistance. The total thrust is distributed based on the flight conditions to the thrust from the inner bypass and / or the outer bypass. Based on the thrust of the inner duct and / or the thrust of the outer duct, the opening of the splitter ring plate and the degree of opening of the outer duct bleed valve and / or the inner duct bleed valve are adjusted to distribute the air flow into the inner duct and / or the outer duct, as well as the air flow into the hydrogen fuel cell. Based on the thrust of the inner duct and / or the thrust of the outer duct, the airflow into the inner duct and / or the outer duct, and the airflow into the hydrogen fuel cell, and in combination with the flight Mach number, the Mach number at the exit of the inner duct and / or the exit of the outer duct is obtained. Based on flight conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined according to the Mach number at the exit of the inner duct and / or the Mach number at the exit of the outer bypass duct, and / or the output power of the hydrogen fuel cell. Define the balance between the output power of the hydrogen fuel cell and the power of the compression system, where the power of the compression system includes the power requirements of the inner compressor and the power requirements of the outer fan; The current compression system power is obtained based on the internal compressor pressure ratio and / or external fan pressure ratio, as well as the air flow rate allocated into the internal duct and / or external duct, and the air flow rate entering the hydrogen fuel cell. Based on the current compression system power, determine whether the current compression system power meets the balance relationship. If not, iteratively optimize by adjusting the opening degree of the split ring plate and the opening degree of the outer bypass bleed valve and / or the inner bypass bleed valve until the balance relationship is met.

[0012] In one embodiment, the balance between the output power of the hydrogen fuel cell and the power of the compression system is as follows:

[0013] In the formula, This refers to the output power of the hydrogen fuel cell; To compress system power and meet ; in, To meet the internal compressor power requirements, The formula for calculating the power requirement of the duct fan is as follows: ,

[0014] In the formula, For incoming airflow; Total incoming flow temperature; For the boost ratio of the bypass fan; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The total inlet temperature of the internal compressor; It is the specific heat at constant pressure of a gas; For the internal compressor pressure ratio; It represents the air insulation index.

[0015] In one embodiment, the output power of the hydrogen fuel cell is:

[0016] In the formula, This refers to the output power of the hydrogen fuel cell; For hydrogen fuel cell efficiency; This is the lower heating value of hydrogen. This refers to the hydrogen flow rate entering the hydrogen fuel cell; where the relationship between the hydrogen required for the chemical reaction in the hydrogen fuel cell and the air flow rate supporting the chemical reaction in the hydrogen fuel cell is as follows: , Excess gas coefficient; This refers to the airflow rate entering the hydrogen fuel cell.

[0017] In one embodiment, the relationship between the airflow rates allocated to the inner duct and / or outer duct is as follows:

[0018]

[0019] In the formula, To propel airflow through the bypass duct; This is the airflow that enters the hydrogen fuel cell through the outer bypass bleed valve; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The airflow rate entering the outer fan; For the opening of the flow divider ring plate, , To the height of the inner meaning of the Tao, This refers to the blade height of the bypass fan.

[0020] In one embodiment, the Mach number at the outlet of the inner duct and / or the outer duct is obtained based on the thrust of the inner duct and / or the thrust of the outer duct, the airflow into the inner duct and / or the outer duct, and the airflow into the hydrogen fuel cell, combined with the flight Mach number. The calculation formula is as follows:

[0021]

[0022] In the formula, For the thrust of the bypass duct; For the driving force of the inner Tao; The speed of sound at the power unit's inlet; The speed of sound at the outlet of the outer bypass duct; The speed of sound at the local exit of the channel; The Mach number at the outlet of the bypass duct; The Mach number at the exit of the inner channel; The flight Mach number; For the pressure at the outlet of the bypass duct; This is to alleviate the pressure on the export of internal channels; Due to environmental pressures; The area of ​​the outer duct outlet; The area of ​​the exit of the inner lane; To propel airflow through the bypass duct; To propel the airflow within the inner channel; The airflow rate entering the hydrogen fuel cell; This refers to the flow rate of hydrogen entering the hydrogen fuel cell.

[0023] In one embodiment, the flight conditions include: subsonic low-altitude flight condition, subsonic high-altitude flight condition, supersonic low-altitude flight condition, and supersonic high-altitude flight condition.

[0024] In one embodiment, based on flight conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined according to the Mach number at the exit of the inner duct and / or the Mach number at the exit of the outer bypass duct, and / or the output power of the hydrogen fuel cell, including: When operating under subsonic low-altitude conditions or supersonic high-altitude conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined based on the Mach number at the outlet of the inner duct and / or the Mach number at the outlet of the outer bypass duct. When operating under subsonic high-altitude or supersonic low-altitude conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined based on the Mach number at the outlet of the inner duct and / or the Mach number at the outlet of the outer bypass duct, as well as the output power of the hydrogen fuel cell.

[0025] Compared with the prior art, the beneficial effects of the present invention are: This invention provides an airflow control method for a hydrogen fuel cell propulsion system used in transonic flight. Addressing the challenges of large variations in airflow parameters and the difficulty in matching the gas supply requirements of the hydrogen fuel cell with the propulsion airflow requirements under transonic flight conditions, this invention proposes an airflow control method based on graded utilization and dynamic allocation of airflow. This method achieves airflow path reconstruction and parameter matching for the propulsion system at different flight operating conditions by adjusting the flow divider ring plate, the inner bleed valve, and the outer bypass bleed valve.

[0026] This invention proposes an airflow control method for a hydrogen fuel cell power plant used in transonic flight. By incorporating key components such as an outer bypass fan, a splitter ring plate, an inner compressor, a hydrogen fuel cell, an inner bleed air valve, an outer bypass bleed air valve, a drive motor, and an exhaust nozzle, a flow organization structure is constructed that enables the coordinated operation of different airflow paths under wide speed and airspace flight conditions. Through coordinated adjustment of airflow path allocation, aerodynamic parameter optimization, and dynamic matching of hydrogen fuel cell power generation and compression system power consumption, the ratio of inner and outer bypass airflow and the overall system pressure ratio are continuously adjustable, thereby maintaining effective airflow control of the power plant under different flight operating conditions.

[0027] Compared to traditional aero engines, this invention eliminates high-temperature rotating components such as the combustion chamber and turbine, uses a hydrogen fuel cell as the core of energy conversion, and achieves airflow pressurization through an electrically driven compression component. It boasts advantages such as simplified structure, low carbon emissions, and strong adaptability. Furthermore, through a multi-parameter coordinated airflow management strategy, the system can maintain stable operation and meet thrust requirements across a wide speed and airspace range.

[0028] This invention has a simple structure, strong controllability, and good engineering application prospects. It can be widely used in fields such as new green aviation power plants, long-endurance UAVs, and high-altitude high-speed flight platforms. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a hydrogen fuel cell power unit for transonic flight provided by the present invention. Figure 2 A flowchart of the airflow control method for a hydrogen fuel cell power unit for transonic flight provided by the present invention; Figure 3 A diagram illustrating the operating strategies of hydrogen fuel cell power units under different flight conditions. Figure 4 This is a schematic diagram showing the geometric parameters of the splitter ring plate and the inner channel; Figure 5 A schematic diagram of a power unit operating under low subsonic and low-altitude conditions. Figure 6 A schematic diagram of a power unit operating under high subsonic low-altitude conditions. Figure 7This is a schematic diagram of a power unit operating under subsonic high-altitude conditions. Figure 8 This is a schematic diagram of the power unit under supersonic low-altitude operating conditions. Figure 9 This is a schematic diagram of the power unit under supersonic high-altitude conditions. Detailed Implementation

[0030] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0031] This invention addresses the following problems in airflow organization and energy utilization of the "hydrogen fuel cell + propeller or ducted fan" configuration under transonic and supersonic flight conditions: 1) During high-speed flight, the high intake velocity of the power unit makes it easy for the fan / propeller to generate shock waves and reduce aerodynamic efficiency. Furthermore, the insufficient pressure ratio of the fan / propeller results in insufficient exhaust velocity, making it difficult to generate the required thrust and inlet / outlet momentum difference; 2) During high-altitude flight, the thin atmosphere makes it impossible for the fan / propeller to provide the high-pressure air required for the chemical reaction of the hydrogen fuel cell due to insufficient pressure ratio. This results in insufficient output power of the hydrogen fuel cell, making it difficult to match the power consumption required for the propeller / ducted fan to generate thrust.

[0032] The purpose of this invention is to provide an airflow control method for a hydrogen fuel cell power unit used in transonic flight. This method compresses the airflow through the independent or combined operation of an outer bypass fan (low pressure ratio) and an inner compressor (high pressure ratio), forming a compression system that meets the pressure ratio requirements under different flight conditions. Furthermore, it distributes the airflow between the outer and inner bypass fans and the hydrogen fuel cell cathode supply flow through structures such as a flow divider ring plate and bleed valves, thus forming an airflow organization and management method capable of supporting different flight conditions. Through airflow path allocation, airflow parameter adjustment, and airflow mixing and exhaust, the method achieves coordinated adjustment and reasonable matching of the hydrogen fuel cell output power, compression system power consumption, and thrust of the power unit in the high-speed and high-altitude ranges. In this process, part of the airflow from the outer bypass duct / inner bypass duct enters the hydrogen fuel cell through the bleed air valve to support its stable power generation; the main airflow from the outer bypass duct is used to generate thrust for low-speed flight, while the airflow from the inner bypass duct enters the inner bypass compressor for pressurization through the split ring plate. Part of the airflow provides the high-pressure air required for the chemical reaction of the hydrogen fuel cell during high-altitude flight, and the remaining airflow mixes with the exhaust gas of the hydrogen fuel cell to form a high-speed jet in the tail nozzle, supporting the generation of the momentum difference and thrust required for the power unit at high-speed flight.

[0033] To achieve the above objectives, see Figure 1 and Figures 4-9As shown, the present invention provides a hydrogen fuel cell power unit for transonic flight. The unit provides power to the aircraft and includes a duct, an outer bypass fan 101 disposed at the front end of the duct, an inner compressor 201 disposed inside the duct, a hydrogen fuel cell 400, a first drive mechanism 401 for driving the outer bypass fan 101, and a second drive mechanism 402 for driving the inner compressor 201. The duct includes an inner duct 200 and an outer duct 100; the inner compressor 201 is disposed within the inner duct 200; A flow divider ring plate 300 is provided at the front end of the duct between the inner duct 200 and the outer duct 100. By adjusting the opening of the flow divider ring plate 300 between the inner duct 200 and the outer duct 100, the flow rate of air entering the inner duct 200 and the outer duct 100 can be controlled. The hydrogen fuel cell 400 is placed in a cavity between the inner duct 200 and the outer duct 100. An outer duct bleed valve 102 is provided in the cavity near the front end of the hydrogen fuel cell 400 and near the inner duct 200. An inner duct bleed valve 202 is provided in the cavity near the rear end of the hydrogen fuel cell 400 and near the inner duct 200. An exhaust port 203 is provided in the cavity near the rear end of the hydrogen fuel cell 400 and near the inner duct 200. Gas discharged from the exhaust port 203 enters the tail nozzle 204. The inner duct bleed valve 202 is located behind the inner compressor 201. The hydrogen fuel cell 400 supplies power to the first drive mechanism 401 and the second drive mechanism 402 respectively.

[0034] The first and second drive mechanisms used in this invention are both electric motors.

[0035] The invention also includes a hydrogen storage mechanism for supplying hydrogen to the hydrogen fuel cell; the hydrogen storage mechanism is used to provide a hydrogen source to the hydrogen fuel cell. Depending on the aircraft structure, the hydrogen storage mechanism is mounted in different locations on the aircraft.

[0036] The air required by the hydrogen fuel cell 400 is the gas flow that enters the hydrogen fuel cell through the outer bleed valve 102 and / or the inner bleed valve 202.

[0037] This invention provides an airflow control method for a hydrogen fuel cell power unit used in transonic flight, based on a hydrogen fuel cell power unit for transonic flight. The method uses the incoming air entering the power unit as a unified air source and controls the airflow through a splitting ring plate, an inner bleed valve, and an outer bleed valve, so that the airflow is dynamically distributed between the duct and the hydrogen fuel cell air supply channel, thereby achieving a coordinated match between thrust demand and hydrogen fuel cell power supply demand under different flight operating conditions.

[0038] See Figure 2As shown, an airflow control method for a hydrogen fuel cell power unit used in transonic flight includes: S1. Determine the flight Mach number and air resistance based on the aircraft's flight conditions; obtain the total thrust under these flight conditions based on the air resistance. The flight conditions in this invention include: subsonic low-altitude flight condition, subsonic high-altitude flight condition, supersonic low-altitude flight condition, and supersonic high-altitude flight condition.

[0039] During flight, air resistance With flight Mach number The following relationship exists:

[0040] In the formula, For the aircraft at an altitude of air density below; For reference area; The speed of sound in the local area; This is the drag coefficient; The flight Mach number; For air resistance; The total thrust generated by the power unit and the air resistance force on it satisfy the following relationship:

[0041] In the formula, Total thrust; This is air resistance. Therefore, according to air resistance... Obtain the total thrust under a certain flight condition .

[0042] S2. Distribute the total thrust to the inner bypass thrust and / or outer bypass thrust based on the flight conditions; Total thrust originates from changes in airflow, and its basic thrust relationship is expressed as:

[0043] In the formula, For the thrust of the bypass duct; It is the driving force behind the inner meaning of Tao.

[0044] This invention distributes the total thrust to the inner bypass thrust and / or outer bypass thrust according to the flight conditions; See Figure 3 The diagram shows the operating strategies of a hydrogen fuel cell power unit under different flight conditions. Under subsonic, low-altitude operating conditions, the atmospheric density is high, and the airflow compressed by the bypass fan can meet the gas supply requirements of the hydrogen fuel cell. At this time, the power unit mainly generates thrust from the bypass airflow, the splitter ring plate remains closed, and the inner compressor basically does not participate in airflow compression.

[0045] Under subsonic high-altitude conditions, due to the reduced atmospheric density, the airflow pressure compressed by the bypass fan is insufficient to meet the oxygen supply pressure required for stable operation of the hydrogen fuel cell. Therefore, an inner compressor is needed to further compress part of the airflow. At this time, the splitter ring plate opens slightly, allowing some airflow to enter the inner compressor channel. The bypass airflow still undertakes the main propulsion task, while the inner airflow is mainly used to increase the gas supply pressure to the hydrogen fuel cell.

[0046] Under supersonic low-altitude conditions, the thrust demand of the power unit increases significantly. At this time, by increasing the opening of the splitter ring plate, more airflow can be introduced into the inner compressor channel to improve the overall pressure ratio of the system. Since the air density at low altitude is high, the outer bypass channel can still provide a certain proportion of high-pressure gas source for the hydrogen fuel cell. Therefore, part of the outer bypass airflow is introduced into the hydrogen fuel cell to participate in the reaction.

[0047] Under supersonic high-altitude conditions, the atmospheric density decreases further. To ensure the thrust of the power unit and the gas supply pressure to the hydrogen fuel cell, most of the airflow needs to be introduced into the inner compressor for high-pressure compression. At this time, the splitter ring plate is basically fully open, while the outer bypass channel is closed or nearly closed. Part of the compressed high-pressure airflow enters the hydrogen fuel cell to participate in the electrochemical reaction, while the remaining airflow mixes with the reaction products of the hydrogen fuel cell and expands in the tail nozzle to form a high-speed jet.

[0048] S3. Based on the thrust of the inner duct and / or the thrust of the outer duct, adjust the opening of the splitter ring plate and the opening degree of the outer duct bleed valve and / or the inner duct bleed valve to distribute the air flow into the inner duct and / or the outer duct, as well as the air flow into the hydrogen fuel cell. The relationship between the airflow into the inner duct and / or outer duct is as follows:

[0049]

[0050] In the formula, To propel airflow through the bypass duct; This is the airflow that enters the hydrogen fuel cell through the outer bypass bleed valve; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The airflow rate entering the outer fan; See Figure 4 As shown, The flow divider ring plate has a 300° opening. , To embody the height of Tao 200, The blade height of the bypass fan 101.

[0051] S4. Based on the thrust of the inner duct and / or the thrust of the outer duct, the airflow into the inner duct and / or the outer duct, and the airflow into the hydrogen fuel cell, and in combination with the flight Mach number, obtain the Mach number at the outlet of the inner duct and / or the Mach number at the outlet of the outer duct. Based on the thrust of the inner duct and / or the thrust of the outer duct, the airflow into the inner duct and / or the outer duct, and the airflow into the hydrogen fuel cell, and in conjunction with the flight Mach number, the Mach number at the exit of the inner duct and / or the exit of the outer duct is obtained. The calculation formula is as follows:

[0052]

[0053] In the formula, For the thrust of the bypass duct; For the driving force of the inner Tao; The speed of sound at the power unit's inlet; The speed of sound at the outlet of the outer bypass duct; The speed of sound at the local exit of the channel; The Mach number at the outlet of the bypass duct; The Mach number at the exit of the inner channel; The flight Mach number; For the pressure at the outlet of the bypass duct; This is to alleviate the pressure on the export of internal channels; Due to environmental pressures; The area of ​​the outer duct outlet; The area of ​​the exit of the inner lane; To propel airflow through the bypass duct; To propel the airflow within the inner channel; The airflow rate entering the hydrogen fuel cell; This refers to the flow rate of hydrogen entering the hydrogen fuel cell.

[0054] S5. Based on flight conditions, determine the inner compressor pressure ratio and / or outer fan pressure ratio according to the Mach number at the exit of the inner duct and / or the exit of the outer bypass duct, and / or the output power of the hydrogen fuel cell, specifically including: When operating under subsonic low-altitude conditions or supersonic high-altitude conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined based on the Mach number at the outlet of the inner duct and / or the Mach number at the outlet of the outer bypass duct. When operating under subsonic high-altitude or supersonic low-altitude conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined based on the Mach number at the outlet of the inner duct and / or the Mach number at the outlet of the outer bypass duct, as well as the output power of the hydrogen fuel cell.

[0055] S6. Define the balance between the output power of the hydrogen fuel cell and the power of the compression system, wherein the power of the compression system includes the power requirements of the inner compressor and the power requirements of the outer fan. The balance between the output power of the hydrogen fuel cell and the power of the compression system is as follows:

[0056] In the formula, This refers to the output power of the hydrogen fuel cell; To compress system power and meet ; in, To meet the internal compressor power requirements, The formula for calculating the power requirement of the duct fan is as follows: ,

[0057] In the formula, For incoming airflow; Total incoming flow temperature; For the boost ratio of the bypass fan; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The total inlet temperature of the internal compressor; It is the specific heat at constant pressure of a gas; For the internal compressor pressure ratio; It represents the air insulation index.

[0058] The output power of the hydrogen fuel cell is:

[0059] In the formula, This refers to the output power of the hydrogen fuel cell; For hydrogen fuel cell efficiency; This is the lower heating value of hydrogen. This refers to the hydrogen flow rate entering the hydrogen fuel cell; where the relationship between the hydrogen required for the chemical reaction in the hydrogen fuel cell and the air flow rate supporting the chemical reaction in the hydrogen fuel cell is as follows: , Excess gas coefficient; This refers to the airflow rate entering the hydrogen fuel cell.

[0060] S7. Obtain the current compression system power based on the internal compressor pressure ratio and / or external bypass fan pressure ratio, as well as the air flow rate allocated into the internal duct and / or external bypass duct, and the air flow rate entering the hydrogen fuel cell. In this invention, the power unit's compression components mainly include an outer bypass fan and an inner compressor, and their total power requirement can be expressed as:

[0061] In the formula, This represents the current power of the compression system. For the power requirements of the bypass fan; This is to meet the internal compressor power requirements.

[0062] Considering the energy gain relationship during the airflow compression process, the power demand of the compression system can be approximated as:

[0063] In the formula, This represents the current power of the compression system. For incoming airflow; Total incoming flow temperature; For the boost ratio of the bypass fan; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The total inlet temperature of the internal compressor; It is the specific heat at constant pressure of a gas; For the internal compressor pressure ratio; It represents the air insulation index.

[0064] S8. Based on the current compression system power, determine whether the current compression system power meets the balance relationship. If not, iteratively optimize by adjusting the opening degree of the split ring plate and the opening degree of the outer bypass bleed valve and / or the inner bypass bleed valve until the balance relationship is met.

[0065] To illustrate the present invention, an airflow control method for a hydrogen fuel cell power unit for transonic flight is provided. The following establishes a thrust-drag constraint relationship based on the thrust generated by the airflow from the power unit; and establishes a balance constraint relationship between the power generation of the hydrogen fuel cell and the power consumption of the compression system. Based on different flight conditions, the constraint relationship is satisfied by adjusting the opening of the shunt ring plate and the bleed air valve, thereby achieving a coordinated match between the thrust requirement and the power supply requirement of the hydrogen fuel cell at different flight conditions.

[0066] A method for airflow control of a hydrogen fuel cell power unit for transonic flight, comprising: Let the airflow entering the duct fan be the reference flow rate. ; The incoming airflow of the power plant is divided into three parts according to function: the bypass propulsion airflow. Internal propulsion airflow Hydrogen fuel cell gas supply flow It satisfies the airflow continuity relationship:

[0067] Among them, the gas supply flow of hydrogen fuel cells It is supported by a portion of the airflow from the outer bypass duct passing through the outer bypass bleed valve and a portion of the airflow from the inner bypass duct passing through the inner bypass bleed valve.

[0068] In the formula, This is the airflow that enters the hydrogen fuel cell through the bleed air valve; This is the gas flow that enters the hydrogen fuel cell through the internal bleed valve.

[0069] The relationship between the required hydrogen gas and the air flow rate supporting the hydrogen fuel cell for the appropriate chemical reaction ratio is as follows: Considering the excess residual gas coefficient Typically, 1.5 to 2 is taken. .

[0070] The flow divider ring plate adjusts the airflow rate entering the inner compressor according to the flight altitude and flight speed, specifically as follows:

[0071] Therefore, the internal / external bypass airflow distribution relationship is obtained:

[0072]

[0073] In the formula, To propel airflow through the bypass duct; This is the airflow that enters the hydrogen fuel cell through the outer bypass bleed valve; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The airflow rate entering the outer fan; See Figure 4 As shown, The flow divider ring plate has a 300° opening. , To embody the height of Tao 200, The blade height of the bypass fan 101; The thrust of the power unit provided by this invention originates from changes in airflow, and its basic thrust relationship is expressed as follows:

[0074] In the formula, For the thrust of the bypass duct; For the driving force of the inner Tao; For total thrust; specifically manifested as:

[0075]

[0076] In the formula, For the thrust of the bypass duct; For the driving force of the inner Tao; The speed of sound at the power unit's inlet; The speed of sound at the outlet of the outer bypass duct; The speed of sound at the local exit of the channel; The Mach number at the outlet of the bypass duct; The Mach number at the exit of the inner channel; The flight Mach number; For the pressure at the outlet of the bypass duct; This is to alleviate the pressure on the export of internal channels; Due to environmental pressures; The area of ​​the outer duct outlet; The area of ​​the exit of the inner lane; To propel airflow through the bypass duct; To propel the airflow within the inner channel; The airflow rate entering the hydrogen fuel cell; This refers to the hydrogen flow rate entering the hydrogen fuel cell. Under the condition of full expansion to maximum exhaust velocity, the outer bypass duct outlet... Mach number and Mach number at the nozzle exit They are respectively:

[0077]

[0078] In the formula, The Mach number at the outlet of the bypass duct; The Mach number at the exit of the inner channel; , The flight Mach number; For the boost ratio of the bypass fan; For the internal compressor pressure ratio; This refers to the total pressure at the outlet of the duct fan. Total incoming pressure; The total outlet pressure of the internal compressor; The air insulation index; The total inlet pressure of the internal compressor; It is the total pressure recovery coefficient of the intake manifold formed by the splitter ring plate.

[0079] and The relationship is:

[0080] and The relationship is:

[0081] In the formula, ; ; The speed of sound at the outlet of the outer bypass duct; The speed of sound at the local exit of the channel; The speed of sound at the local import point of the power unit.

[0082] During flight, the thrust generated by the power unit and the air resistance force on the aircraft satisfy the following conditions: Among them, air resistance With flight Mach number The following relationship exists:

[0083] In the formula, For the aircraft at an altitude of air density below; For reference area; The speed of sound in the local area; This is the drag coefficient; The flight Mach number; For air resistance; Will Substituting the thrust-drag relationship:

[0084] In the formula, For the thrust of the bypass duct; It is the driving force behind the inner meaning of Tao.

[0085] From an engineering thermodynamics perspective, hydrogen fuel cells serve as the energy source for a power plant. Gas flow enters the fuel cell through the inner and outer bypass bleed valves to undergo a chemical reaction, thereby supporting the energy demand of the driving compression system. The power plant's gas flow compression components mainly include the outer bypass fan and the inner compressor, and their total power requirement can be expressed as:

[0086] In the formula, To compress system power; For the power requirements of the bypass fan; This is to meet the internal compressor power requirements.

[0087] Considering the energy gain relationship during the airflow compression process, the power demand of the compression system can be approximated as:

[0088] In the formula, For the specific heat of a gas at constant pressure, For the total incoming temperature, The total temperature at the inlet of the internal compressor.

[0089] The output power of a hydrogen fuel cell approximately satisfies the following relationship with the gas supply flow rate:

[0090] In the formula, For hydrogen fuel cell efficiency, The flow rate of hydrogen entering the hydrogen fuel cell, This is the lower heating value of hydrogen.

[0091] For hydrogen fuel cells, the cathode air supply pressure has a significant impact on the cell's output performance and system efficiency. As the air supply pressure increases, the partial pressure of oxygen at the cathode increases, leading to a higher concentration of reactants on the electrode surface. This reduces concentration polarization and activation polarization losses, thereby increasing the fuel cell's output voltage. According to the Nernst equation, the fuel cell output voltage... It can be represented as:

[0092] In the formula, This represents the theoretical voltage of a fuel cell under standard conditions. It is Faraday's constant; This is the universal gas constant; T This refers to the operating temperature of the fuel cell. This refers to the pressure of hydrogen gas. To supply gas pressure to the hydrogen fuel cell; It is the standard atmospheric pressure.

[0093] According to Faraday's law, the output current of a hydrogen fuel cell is... for:

[0094] In the formula, For hydrogen, the number of electrons transferred per particle is [number]. Pick ; This refers to the molar mass of hydrogen gas. The flow rate of hydrogen entering the hydrogen fuel cell; Under ideal conditions where polarization and ohmic losses are neglected, the output power of a hydrogen fuel cell can be expressed as:

[0095] According to the formula The efficiency of a hydrogen fuel cell can be expressed as:

[0096] The formula Substitution We can obtain:

[0097] From the formula It can be seen that the efficiency of hydrogen fuel cells increases with increasing gas supply pressure.

[0098] To ensure stable operation of the power unit, the power balance relationship must be satisfied:

[0099] Right now:

[0100] Will Substitution The gas supply flow constraint entering the hydrogen fuel cell through the bleed valve is obtained:

[0101] In the formula, For hydrogen fuel cell efficiency; This is the lower heating value of hydrogen. Power requirements of the compression system; Equation (25) is used to determine the range of airflow required for hydrogen fuel cells under different flight conditions.

[0102] Based on With formula It can solve for the thrust range of the power plant under flight conditions. For a given flight condition, firstly, the formula is used... With formula Calculate the inlet and outlet momentum difference of the bypass and inlet airflows respectively; combine the flight Mach number and flight altitude parameters, and use the formula... and Achieving coordinated distribution of airflow between the inner and outer ducts and the gas supply to the hydrogen fuel cell cathode. (Incoming flow Mach number) Given the input conditions, solve for the duct outlet. and inner nozzle outlet Then, according to the formula Japanese style The bypass fan boost ratio is determined by iterative calculation using equations (10) and (12). and the internal compressor pressure ratio Finally, the obtained boost ratio parameter is substituted into the formula. The system power balance constraints must be met.

[0103] It should be noted that as the flight altitude increases, atmospheric pressure gradually decreases, and the air pressure compressed by the outer bypass fan alone is insufficient to meet the reaction requirements of the hydrogen fuel cell. Therefore, the inner compressor needs to operate continuously to provide a high-pressure airflow, which is then introduced into the hydrogen fuel cell via the inner bleed valve to participate in the electrochemical reaction, ensuring the normal operation of the system.

[0104] Based on equations (11), (12), (13), (14), (7), (8), (4), (5), (9), and (10), this invention can determine the correspondence between the flight Mach number and flight altitude and the required boost ratio of the compression system:

[0105] This invention achieves dynamic proportional distribution of airflow between the bypass duct and the hydrogen fuel cell supply channel under different flight operating conditions by effectively controlling airflow and dynamically matching the output power of the hydrogen fuel cell with the power consumption of the bypass fan / inner compressor.

[0106] To further illustrate the present invention, an airflow control method for a hydrogen fuel cell power unit used in transonic flight is provided, which is explained in conjunction with specific flight conditions.

[0107] See Figure 5 As shown in the schematic diagram of the power unit under subsonic low-altitude conditions, the atmospheric density is relatively high during subsonic flight. The air compressed by the bypass fan 101 can meet the gas pressure requirements of the hydrogen fuel cell, thereby maintaining the stable output of electrical energy from the hydrogen fuel cell. Therefore, the shunt ring plate 300 is adjusted to the closed state. A small portion of the airflow from the outer bypass duct 100 enters the hydrogen fuel cell 400 through the outer bypass bleed valve 102 to generate thrust, while the majority of the remaining airflow expands in the outer bypass duct 100 to form the main thrust. The gas after reaction in the hydrogen fuel cell 400 is discharged from the outlet 203 to the tail nozzle 204 to form auxiliary thrust.

[0108] After being compressed by the bypass fan, the airflow expands directly in the bypass duct to generate thrust, which is approximately expressed by equation (7):

[0109] In the formula, For the thrust of the bypass duct; The speed of sound at the power unit's inlet; The speed of sound at the outlet of the outer bypass duct; This is the airflow that enters the hydrogen fuel cell through the bleed air valve; The Mach number at the outlet of the bypass duct; The flight Mach number; For the pressure at the outlet of the bypass duct; The area of ​​the outer duct outlet; It propels the airflow through the outer bypass duct.

[0110] It should be noted that under this subsonic low-altitude operating condition, the thrust of the aircraft mainly comes from the increase in bypass momentum. The auxiliary thrust formed by the gas after the hydrogen fuel cell reaction in the tail nozzle is small and can therefore be ignored.

[0111] Based on the balance between power generation and power consumption of the hydrogen fuel cell and the thrust-drag relationship, and according to equations (1), (2), (22), (23), (7), (8), (11), and (12), corresponding constraint equations are established:

[0112]

[0113]

[0114]

[0115]

[0116] in, This represents the net pressure difference force acting on the outer bypass duct.

[0117] The bypass thrust is obtained based on flight requirements, and the bypass outlet is calculated by adjusting the fuel cell cathode gas supply flow rate in conjunction with the bleed air valve. Then, combine equations (9) and (11) to determine the bypass fan pressure ratio requirement; then perform power balance verification to ensure that the fuel cell output power meets the system requirements, and verify that the air supply pressure is compatible with the fuel cell requirements and the bypass fan pressure ratio matches the flight thrust; if the conditions are not met, iterative optimization is performed by adjusting parameters such as the bleed air valve flow rate until the thrust and power supply requirements are met.

[0118] Under low subsonic, low-altitude operating conditions, by adjusting the opening of the splitter ring plate... This allows us to obtain the airflow distribution relationship that satisfies the constraints and the corresponding range of variation: ; .

[0119] To ensure subsonic flight efficiency, the bypass fan pressure ratio is typically: .

[0120] See Figure 6 The diagram shows a power plant in high subsonic, low-altitude operation. In subsonic conditions, the aerodynamic drag on the power plant increases with the Mach number. To maintain normal flight, the engine thrust needs to be increased accordingly. (From the equation...) Japanese style It can be seen that the thrust increase requires a higher pressure ratio of the bypass fan (101). Increase. However, limited by the fan's own pressure ratio limit, relying solely on the bypass fan for pressurization is insufficient to meet the demands of high Mach number flight. Therefore, it is necessary to open the splitter ring plate 300 and start the inner compressor 201, introducing part of the incoming flow into the inner compressor 201 for further pressurization. The pressurized airflow mixes with the exhaust gas from the hydrogen fuel cell in the tail nozzle 204 and expands to do work, jointly generating thrust. At this time, the thrust of the power unit is approximately equal to that of equation (6):

[0121] In the formula, For the thrust of the bypass duct; For the driving force of the inner Tao; This is the total thrust.

[0122] Based on the balance between power generation and power consumption of the hydrogen fuel cell and the thrust-drag relationship, and according to equations (1), (2), (24), (25), (7), (8), (13), and (14), corresponding constraint equations are established:

[0123]

[0124]

[0125]

[0126]

[0127] in, , , representing the net pressure difference force between the external and internal channels, respectively.

[0128] The thrust of the inner and outer bypass ducts is allocated according to flight requirements. At the same time, the airflow in the inner and outer bypass ducts is distributed through the splitter ring plate. The flow rate of the fuel cell cathode is adjusted in conjunction with the bleed valve, and the outlet of the outer bypass duct and inner nozzle are calculated. and Then, according to the formula Japanese style Equations (10) and (12) are used to determine the pressure ratio requirements of the bypass fan and the inner compressor. A power balance check is then performed to ensure the fuel cell output power meets system requirements, while verifying that the supply pressure matches the fuel cell requirements and the bypass fan pressure ratio matches the flight thrust. If the conditions are not met, iterative optimization is performed by adjusting parameters such as the shunt ring plate opening until the thrust and power supply requirements are met. Optionally, in high subsonic low-altitude conditions, the shunt ring plate opening is adjusted... This allows us to obtain the airflow distribution relationship that satisfies the constraints and the corresponding range of variation: ; ; .

[0129] To ensure subsonic flight efficiency, the internal compressor pressure ratio is typically: .

[0130] See Figure 7 As shown in the diagram, the power unit operates under subsonic high-altitude conditions. As the flight altitude increases, the atmospheric density decreases, and the air pressure compressed by the bypass fan 101 is insufficient to meet the reaction requirements of the hydrogen fuel cell 400. Therefore, the internal compressor 201 needs to maintain high-speed operation to provide high-pressure airflow that enters the hydrogen fuel cell 400 through the internal bleed valve 202 to participate in the reaction. At this time, the splitter ring plate 300 is adjusted to a small opening. The system still mainly relies on the airflow compressed by the bypass fan 101 to generate thrust. The gas after the hydrogen fuel cell reaction forms auxiliary thrust in the tail nozzle 204.

[0131] Establish the thrust relationship based on equation (7):

[0132] In the formula, For the thrust of the bypass duct; The speed of sound in the local area; The Mach number at the outlet of the bypass duct; The flight Mach number; This is the airflow that enters the hydrogen fuel cell through the bleed air valve; For the pressure at the outlet of the bypass duct; The area of ​​the outer duct outlet; It propels the airflow through the outer bypass duct.

[0133] It should be noted that under subsonic high-altitude conditions, the system thrust still mainly comes from the increase in bypass momentum.

[0134] Based on the balance between power generation and power consumption of the hydrogen fuel cell and the thrust-drag relationship, and according to equations (1), (2), (24), (25), (7), (8), (13), (14), and (22), corresponding constraint equations are established:

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141] in, , representing the net pressure difference force of the outer bypass duct.

[0142] The outer bypass thrust is obtained based on flight requirements. The airflow between the inner and outer bypass ducts is distributed through a splitter ring plate. The bleed air valve is used to adjust the fuel cell cathode air supply flow rate, i.e., the inner bypass duct flow rate. The outer bypass duct outlet flow rate is then calculated. Then, combine equations (9) and (11) to determine the bypass fan pressure ratio requirement; determine the internal compressor pressure ratio according to the fuel cell supply pressure to match the fuel cell requirements, and then perform power balance verification to ensure that the fuel cell output power meets the system requirements and verify that the bypass fan pressure ratio matches the flight thrust; if the conditions are not met, iterative optimization is performed by adjusting parameters such as the shunt ring plate opening until the thrust and energy supply requirements are met.

[0143] Optionally, under subsonic high-altitude operating conditions, the opening of the splitter ring plate can be adjusted. This allows us to obtain the airflow distribution relationship that satisfies the constraints and the corresponding range of variation:

[0144]

[0145] Optionally, the pressure ratio range of the airflow entering the inner compressor is:

[0146] See Figure 8 The diagram shows a schematic of the power unit under supersonic low-altitude conditions. Under supersonic low-altitude conditions, the thrust demand gradually increases with increasing flight speed. Because the supersonic airflow generates a shock wave when passing through the bypass fan 101, aerodynamic efficiency decreases, and the airflow expansion in the bypass duct 100 cannot meet the thrust demand. Therefore, the thrust is mainly generated by the airflow in the inner duct 200 within the tail nozzle 204. Considering the higher air density at low altitudes, the airflow in the bypass duct 100 can serve as the main high-pressure gas source for the hydrogen fuel cell 400. Therefore, the splitter ring plate 300 is in the large opening range. A small portion of the airflow is compressed by the bypass fan 101 and enters the hydrogen fuel cell 400 through the bypass duct 100 to participate in the reaction; the majority of the remaining airflow enters the inner duct 200, and is pressurized by the inner compressor 201 through the splitter ring plate 300. Finally, it mixes with the airflow generated by the reaction of the hydrogen fuel cell 400 in the tail nozzle 204 to form an expanding jet. At this time, the aircraft mainly relies on the inner airflow to provide thrust. The thrust relationship is established according to equation (8) as follows:

[0147] In the formula, For the driving force of the inner Tao; The speed of sound at the power unit's inlet; For the local sound speed at the exit of the inner channel The Mach number at the exit of the inner channel; The flight Mach number; This is to alleviate the pressure on the export of internal channels; Due to environmental pressures; The area of ​​the exit of the inner lane; To propel the airflow within the inner channel; This refers to the flow rate of hydrogen entering the hydrogen fuel cell.

[0148] Based on the balance between power generation and power consumption of the hydrogen fuel cell and the thrust-drag relationship, and according to equations (1), (2), (24), (25), (7), (8), (13), (14), and (22), corresponding constraint equations are established:

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155] in, , representing the net pressure difference force within the channel.

[0156] Under supersonic low-altitude conditions, by adjusting the opening of the splitter ring plate This allows us to obtain the airflow distribution relationship that satisfies the constraints and the corresponding range of variation: ; .

[0157] The thrust of the inner bypass duct is obtained based on flight requirements. At the same time, the airflow between the inner and outer bypass ducts is distributed through the splitter ring plate. The flow rate of the fuel cell cathode is adjusted by the bleed air valve, i.e., the flow rate of the outer bypass duct. The tail nozzle of the inner bypass duct is also calculated. Then, by combining equations (10) and (12), the pressure ratio requirement of the inner compressor is determined; the pressure ratio of the outer bypass fan is determined according to the fuel cell supply pressure to meet the fuel cell requirements, and then the power balance is checked to ensure that the fuel cell output power meets the system requirements; if the conditions are not met, the parameters such as the opening of the shunt ring plate are iteratively optimized until the thrust and power supply requirements are met.

[0158] Optionally, the pressure ratio range of the airflow entering the inner compressor is: .

[0159] See Figure 9 As shown in the schematic diagram of the power unit under supersonic high-altitude conditions, under supersonic flight conditions, the atmospheric density is significantly reduced, and the system needs to provide high-pressure air through the inner compressor 201, while the outer bypass airflow is closed to reduce drag. At this time, the splitter ring plate 300 is in a fully open state, and part of the airflow enters the hydrogen fuel cell 400 for reaction, while the remaining airflow mixes and expands with the gas after reaction in the hydrogen fuel cell in the tail nozzle 204 to form thrust. The thrust is established according to equation (8):

[0160] In the formula, For the driving force of the inner Tao; The speed of sound at the power unit's inlet; The speed of sound at the local exit of the channel; This is the gas flow that enters the hydrogen fuel cell through the internal bleed valve; The Mach number at the exit of the inner channel; The flight Mach number; This is to alleviate the pressure on the export of internal channels; Due to environmental pressures; The area of ​​the exit of the inner lane; To propel the airflow within the inner channel; This refers to the flow rate of hydrogen entering the hydrogen fuel cell.

[0161] Based on the balance between power generation and power consumption of the hydrogen fuel cell and the thrust-drag relationship, and according to equations (1), (2), (24), (25), (7), (8), (13), and (14), corresponding constraint equations are established:

[0162]

[0163]

[0164]

[0165]

[0166] in, It represents the net pressure difference force within the channel.

[0167] The thrust of the inner duct is obtained based on flight requirements, and the inner duct outlet is calculated by adjusting the fuel cell cathode gas supply flow rate in conjunction with the bleed air valve. Then, the total boost ratio requirement is determined by combining equations (10) and (12); then, the power balance is checked to ensure that the fuel cell output power meets the system requirements; if the conditions are not met, the parameters such as the bleed valve flow rate are iteratively optimized until the thrust and power supply requirements are met.

[0168] For example, under supersonic high-altitude conditions, the opening of the diverter ring plate can be adjusted. This allows us to obtain the airflow distribution relationship that satisfies the constraints and the corresponding range of variation: ; The gas flow entering the hydrogen fuel cell comes entirely from the internal compressor, which is... .

[0169] Optionally, the overall boost ratio is: .

[0170] This invention controls the airflow through a diversion ring plate, an inner bleed valve, and an outer bleed valve, achieving dynamic matching between the power unit's airflow channel configuration and aerodynamic parameters. This enables the system to maintain stable operation within a wide speed and airspace flight envelope, improving the power unit's adaptability while simplifying the structure and reducing emissions.

[0171] The present invention provides a hydrogen fuel cell power unit for transonic flight, and an airflow control method for the hydrogen fuel cell power unit for transonic flight, which mainly includes the following aspects: (1) Basic configuration of the power unit: The power unit includes an outer bypass fan, a splitter ring plate, an inner compressor, a hydrogen fuel cell, an inner bleed air valve, an outer bypass bleed air valve, a drive motor, and an exhaust nozzle. Among these: The hydrogen fuel cell provides electrical power to the motor; the motor drives the outer bypass fan and the inner compressor to compress the air; some of the compressed air enters the hydrogen fuel cell to participate in the electrochemical reaction; the remaining gas expands through the nozzle to generate thrust.

[0172] (2) Multi-duct airflow organization structure: Based on the airflow organization method of inner and outer bypass: the outer bypass airflow is compressed by the outer bypass fan and directly generates thrust; the inner bypass airflow is pressurized by the inner bypass compressor and mixed with the reaction products of the hydrogen fuel cell to expand and generate thrust; the three-channel and above structures based on this principle are all within the scope of protection of this invention.

[0173] (3) Electric drive compression propulsion scheme: a propulsion method that uses hydrogen fuel cells as the energy source, and generates high-speed airflow by driving the outer bypass fan and inner compressor through the motor, and then expands through the nozzle to form thrust.

[0174] (4) Hybrid propulsion configuration: a hybrid power device formed by combining the propulsion principle of the present invention with a traditional gas turbine power unit.

[0175] (5) Pneumatic jet propulsion principle: Pneumatic jet propulsion method that generates thrust by driving the compression system with a motor and combining it with the expansion of the tail nozzle.

[0176] (6) Wide-range operating adjustment mechanism: Stable operation under different flight conditions is achieved through the following adjustments: power distribution of the hydrogen fuel cell between the outer bypass fan and the inner compressor; regulation of the hydrogen fuel cell air supply by the inner and outer bypass bleed air valves; and adjustment of the intake channel status by the splitter plate. (7) Distributed propulsion configuration: a distributed propulsion arrangement consisting of multiple power units, and a configuration that achieves horizontal or vertical thrust based on the power units.

[0177] (8) Transonic airflow organization achieved by the split ring plate: The ratio of the flow rate of the inner and outer bypass is continuously adjusted by the split ring plate with adjustable opening, thereby maintaining the stable operation of the power unit in a wide speed range and wide air space range.

[0178] (9) Operating range: The power unit is suitable for flight conditions from sea level to 20 km altitude and 0 < Ma < 6.

[0179] (10) High-pressure gas supply airflow control method for hydrogen fuel cell: The high-pressure gas flow at the outlet of the internal compressor is distributed according to functional requirements. A portion of it enters the hydrogen fuel cell to participate in the electrochemical reaction to generate electricity. The remaining high-pressure gas flow mixes and expands with the high-temperature gas generated by the reaction of the hydrogen fuel cell in the tail nozzle, thereby realizing the coupling design of propulsion and energy supply and improving the overall energy utilization efficiency of the system.

[0180] (11) Multi-parameter coupled regulation power plant control method: By coordinating the adjustment of the split ring plate, the inner bleed air valve and the outer bleed air valve, the dynamic reconstruction of the power plant airflow path and airflow parameters under different flight conditions is realized, thereby completing the control of the propulsion airflow and the hydrogen fuel cell supply airflow.

[0181] The present invention provides an airflow control method for a hydrogen fuel cell power plant used in transonic flight, which has the following advantages: Simplified structure: This invention uses a hydrogen fuel cell for power and an electric motor to drive the compression component, eliminating the combustion chamber and turbine structure in traditional aviation gas turbine power units, reducing high-temperature combustion-related components, and lowering the mechanical complexity of the system.

[0182] Strong independent electric drive adjustment capability: The outer bypass fan and inner compressor are driven by electric motors, and their speed and power distribution can be adjusted independently, improving the adjustment capability and working stability of the power unit under different operating conditions.

[0183] Low emission characteristics: Using hydrogen fuel cells as an energy source, there is no fuel combustion process during propulsion, which can reduce carbon and nitrogen oxide emissions and reduce infrared and noise characteristics.

[0184] Wide-range airflow organization capability: By controlling the airflow through the splitter ring plate, inner bleed valve, and outer bleed valve, the power plant can adapt to subsonic to supersonic flight conditions.

[0185] Aerodynamic and power supply coupling matching capability: By supplying hydrogen fuel cells with compressed air and coupling it with the propulsion airflow organization, the thrust requirements of the power unit and the power output of the hydrogen fuel cell are matched.

[0186] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A hydrogen fuel cell power unit for transonic flight, characterized in that, The device provides power to the aircraft, including a duct, an outer bypass fan at the front end of the duct, an inner compressor and a hydrogen fuel cell inside the duct, as well as a first drive mechanism for driving the outer bypass fan and a second drive mechanism for driving the inner compressor. The duct includes an inner duct and an outer duct; the inner compressor is disposed within the inner duct; A flow divider ring plate is provided at the front end of the duct between the inner duct and the outer duct. By adjusting the opening of the flow divider ring plate between the inner duct and the outer duct, the flow rate of air entering the inner duct and the outer duct can be controlled. The hydrogen fuel cell is placed in a cavity between the inner duct and the outer duct. An outer duct bleed valve is provided in the cavity on the front end of the hydrogen fuel cell near the outer duct. An inner duct bleed valve is provided in the cavity on the front end of the hydrogen fuel cell near the inner duct. An exhaust port is provided in the cavity on the rear end of the hydrogen fuel cell near the inner duct. Gas discharged from the exhaust port enters the tail nozzle. The inner duct bleed valve is located behind the inner compressor. The hydrogen fuel cell supplies power to the first drive mechanism and the second drive mechanism, respectively.

2. The hydrogen fuel cell power unit for transonic flight according to claim 1, characterized in that, It also includes a hydrogen storage mechanism that supplies hydrogen to the hydrogen fuel cell.

3. The hydrogen fuel cell power unit for transonic flight according to claim 1, characterized in that, The air required for the hydrogen fuel cell is introduced into the hydrogen fuel cell through an external bleed air valve and / or an internal bleed air valve.

4. A method for airflow control of a hydrogen fuel cell power plant for transonic flight as described in claim 1, characterized in that, include: Determine the flight Mach number and air resistance based on the aircraft's flight conditions; The total thrust under this flight condition is obtained based on air resistance. The total thrust is distributed based on the flight conditions to the thrust from the inner bypass and / or the outer bypass. Based on the thrust of the inner duct and / or the thrust of the outer duct, the opening of the splitter ring plate and the degree of opening of the outer duct bleed valve and / or the inner duct bleed valve are adjusted to distribute the air flow into the inner duct and / or the outer duct, as well as the air flow into the hydrogen fuel cell. Based on the thrust of the inner duct and / or the thrust of the outer duct, the airflow into the inner duct and / or the outer duct, and the airflow into the hydrogen fuel cell, and in combination with the flight Mach number, the Mach number at the exit of the inner duct and / or the exit of the outer duct is obtained. Based on flight conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined according to the Mach number at the exit of the inner duct and / or the Mach number at the exit of the outer bypass duct, and / or the output power of the hydrogen fuel cell. Define the balance between the output power of the hydrogen fuel cell and the power of the compression system, where the power of the compression system includes the power requirements of the inner compressor and the power requirements of the outer fan; The current compression system power is obtained based on the internal compressor pressure ratio and / or external fan pressure ratio, as well as the air flow rate allocated into the internal duct and / or external duct, and the air flow rate entering the hydrogen fuel cell. Based on the current compression system power, determine whether the current compression system power meets the balance relationship. If not, iteratively optimize by adjusting the opening degree of the split ring plate and the opening degree of the outer bypass bleed valve and / or the inner bypass bleed valve until the balance relationship is met.

5. The airflow control method for a hydrogen fuel cell power unit for transonic flight according to claim 4, characterized in that, The balance between the output power of the hydrogen fuel cell and the power of the compression system is as follows: In the formula, This refers to the output power of the hydrogen fuel cell; To compress system power and meet ; in, To meet the internal compressor power requirements, The formula for calculating the power requirement of the duct fan is as follows: ， In the formula, For incoming airflow; Total incoming flow temperature; For the boost ratio of the bypass fan; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The total inlet temperature of the internal compressor; It is the specific heat at constant pressure of a gas; For the internal compressor pressure ratio; It represents the air insulation index.

6. The airflow control method for a hydrogen fuel cell power plant for transonic flight according to claim 5, characterized in that, The output power of the hydrogen fuel cell is: In the formula, This refers to the output power of the hydrogen fuel cell; For hydrogen fuel cell efficiency; This is the lower heating value of hydrogen. This refers to the hydrogen flow rate entering the hydrogen fuel cell; where the relationship between the hydrogen required for the chemical reaction in the hydrogen fuel cell and the air flow rate supporting the chemical reaction in the hydrogen fuel cell is as follows: , Excess gas coefficient; This refers to the airflow rate entering the hydrogen fuel cell.

7. The airflow control method for a hydrogen fuel cell power plant for transonic flight according to claim 4, characterized in that, The relationship between the airflow into the inner duct and / or outer duct is as follows: In the formula, To propel airflow through the bypass duct; This is the airflow that enters the hydrogen fuel cell through the outer bypass bleed valve; To propel the airflow within the inner channel; This is the airflow that enters the hydrogen fuel cell through the internal bleed valve; The airflow rate entering the outer fan; For the opening of the flow divider ring plate, , To the height of the inner meaning of the Tao, This refers to the blade height of the bypass fan.

8. The airflow control method for a hydrogen fuel cell power plant for transonic flight according to claim 7, characterized in that, Based on the thrust of the inner duct and / or the thrust of the outer duct, the airflow into the inner duct and / or the outer duct, and the airflow into the hydrogen fuel cell, and in conjunction with the flight Mach number, the Mach number at the exit of the inner duct and / or the exit of the outer duct is obtained. The calculation formula is as follows: In the formula, For the thrust of the bypass duct; For the driving force of the inner Tao; The speed of sound at the power unit's inlet; The speed of sound at the outlet of the outer bypass duct; The speed of sound at the local exit of the channel; The Mach number at the outlet of the bypass duct; The Mach number at the exit of the inner channel; The flight Mach number; For the pressure at the outlet of the bypass duct; This is to alleviate the pressure on the export of internal channels; Due to environmental pressures; The area of ​​the outer duct outlet; The area of ​​the exit of the inner lane; To propel airflow through the bypass duct; To propel the airflow within the inner channel; The airflow rate entering the hydrogen fuel cell; This refers to the flow rate of hydrogen entering the hydrogen fuel cell.

9. The airflow control method for a hydrogen fuel cell power plant for transonic flight according to claim 4, characterized in that, Flight conditions include: subsonic low-altitude flight condition, subsonic high-altitude flight condition, supersonic low-altitude flight condition, and supersonic high-altitude flight condition.

10. The airflow control method for a hydrogen fuel cell power plant for transonic flight according to claim 9, characterized in that, Based on flight conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined according to the Mach number at the exit of the inner duct and / or the exit of the outer bypass duct, and / or the output power of the hydrogen fuel cell, including: When operating under subsonic low-altitude conditions or supersonic high-altitude conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined based on the Mach number at the outlet of the inner duct and / or the Mach number at the outlet of the outer bypass duct. When operating under subsonic high-altitude or supersonic low-altitude conditions, the pressure ratio of the inner compressor and / or the pressure ratio of the outer fan are determined based on the Mach number at the outlet of the inner duct and / or the Mach number at the outlet of the outer bypass duct, as well as the output power of the hydrogen fuel cell.

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