A bypass electric drive variable cycle turbofan engine

Abstract

An externally driven, electrically powered, variable-cycle turbofan engine relates to aero-turbine engines. It incorporates components from a baseline dual-rotor mixed-emission turbofan engine, including the inlet, fan, high-pressure compressor, combustion chamber, turbine, mixing chamber, and nozzle, with the addition of an electric motor, externally driven fan, electrical equipment, and an externally driven nozzle. By optimizing the thermodynamic cycle and power-to-electricity conversion, this engine can achieve a thermodynamic "variable cycle" under different operating conditions, providing additional electrical energy to the aircraft. During subsonic flight, the electric motor utilizes the core shaft power to drive the externally driven fan, increasing the bypass ratio, reducing fuel consumption, and improving thrust. During supersonic flight, excess air drives the fan to generate electricity, which is then used to replenish the low-pressure shaft of the engine, reducing turbine power and inlet overflow drag. This design requires minimal modifications, is highly feasible, effectively increases engine thrust, reduces fuel consumption, achieves efficient energy utilization, and is suitable for various flight conditions.

Description

Technical Field

[0001] This invention relates to the field of aero-turbine engines, and in particular to a bypass electric-driven variable-cycle turbofan engine with a novel structural form designed to meet the power requirements of next-generation aircraft. Background Art

[0002] Variable cycle engines, by altering the flow path structure and thermodynamic cycle parameters of turbine engines, offer advantages in balancing low-speed and high-altitude flight performance. They are widely recognized as ideal power plants for supersonic aircraft operating at Mach 2-3, injecting new vitality into the development of supersonic aircraft. Currently, the all-electric frame of sixth-generation fighter jets provides new possibilities for the design of variable cycle engines. These engines optimize the thermodynamic cycle through power-to-electricity conversion, providing additional electrical energy to the aircraft and achieving efficient matching of thermodynamic "variable cycle" and power-to-electricity "conversion" under multiple operating conditions. This represents an important development direction and inevitable trend for meeting the high-efficiency flight requirements of future aircraft.

[0003] In recent years, research on variable cycle turbine engines has laid a foundation for the development of sixth-generation fighter jets. Adaptive cycle engines with a third bypass duct have further optimized the engine-injection matching characteristics and provided more favorable thermal management and stealth conditions for aircraft. However, under the all-electric architecture requirements of sixth-generation fighter jets, variable cycle engines also shoulder the important mission of power-to-electric conversion. Achieving thermodynamic "variable cycle" and power-to-electric conversion in multi-condition mission environments has become an inevitable requirement for future sixth-generation fighter jets. On the one hand, the thermodynamic cycle determines the power-to-electric conversion; on the other hand, the power-to-electric conversion affects the thermodynamic cycle. Therefore, the design and control of variable cycle engines should take into account the coupling relationship between thermodynamic "variable cycle" and power-to-electric conversion. Currently, the "variability" of mainstream variable cycle engines mainly relies on mechanical adjustment mechanisms. Research mainly focuses on the influence mechanism and control strategy of mechanical adjustment on thermodynamic "variable cycle," without considering the influence of power-to-electric conversion. No variable cycle engine scheme based on electric drive adjustment of bypass ratio has been proposed. Therefore, it is urgent to carry out research on new variable cycle engine schemes that meet the requirements of thermodynamic "variable cycle" and power-to-electric conversion. Summary of the Invention

[0004] This invention aims to address the above-mentioned needs by providing a bypass-driven electric variable-cycle turbofan engine and its design method. Based on the existing dual-rotor mixed-emission turbofan engine, a generator / motor is added to the low-pressure shaft, and the bypass ratio of the engine is dynamically adjusted by changing the operating state of the bypass fan; an additional bypass duct is added to house the fan, which is driven by the motor to increase the bypass ratio during subsonic flight; and during supersonic flight, the fan is driven to generate electricity based on excess airflow captured by the inlet, which is then used to supplement the power supply of the turbine engine or the onboard power supply.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a design method for an externally bypass electric-driven variable-cycle turbofan engine, comprising the following steps:

[0007] 1) Determine the benchmark engine: Select an existing dual-rotor mixed-displacement turbofan engine as the benchmark. The dual-rotor mixed-displacement turbofan engine includes an intake, fan, high-pressure compressor, combustion chamber, high-pressure turbine, low-pressure turbine, mixing chamber, and nozzle.

[0008] 2) Add an electric motor and bypass fan: Add an electric motor to the low-pressure shaft of the standard dual-rotor mixed-displacement turbofan engine. The electric motor and the low-pressure shaft are connected by a mechanical structure. Extend a third bypass duct behind the intake duct and arrange an bypass fan in the third bypass duct. Ensure that the electric motor and the bypass fan can exchange electrical energy.

[0009] 3) Design of the duct fan and nozzle: Design appropriate fan size and speed according to the working requirements of the duct fan; design a separate duct nozzle to discharge the airflow in the third duct.

[0010] 4) Thermodynamic cycle and power conversion design: Design thermodynamic cycle parameters to ensure that the engine can maintain high efficiency under different operating conditions; design power conversion strategy to achieve coordinated operation of the motor and bypass fan in subsonic and supersonic conditions.

[0011] Thermodynamic cycle parameters include compressor pressure ratio, turbine inlet temperature, and combustion efficiency. The efficiency and stability of the thermodynamic cycle are considered to ensure that the engine maintains efficient and stable operation under different operating conditions.

[0012] Design of power-to-electricity conversion strategy: A collaborative working strategy for the motor and bypass fan is designed. In subsonic conditions, the motor can extract shaft power from the core engine and convert it into electrical energy to supply the bypass fan. In supersonic conditions, the bypass fan can utilize excess airflow captured by the intake duct to generate electricity and supply it to the motor to replenish the low-pressure shaft of the engine. This ensures that the motor and bypass fan maintain efficient and stable performance when working collaboratively.

[0013] This invention provides a bypass electric-driven variable-cycle turbofan engine, based on a benchmark dual-rotor mixed-emission turbofan engine, including an intake, a fan, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a mixing chamber, and a nozzle. It also includes an electric motor, a bypass fan, electrical equipment, and a bypass nozzle. A third bypass extends behind the intake, and a bypass fan is arranged in the third bypass. Airflow within this bypass extends through the bypass fan and exits through a separate bypass nozzle. An electric motor is added to the low-pressure shaft of the benchmark dual-rotor mixed-emission turbofan engine structure. The motor is mechanically connected to the low-pressure shaft and exchanges electrical energy with the bypass fan, electrical equipment, etc.

[0014] The air intake is used to capture incoming airflow;

[0015] The fan, located behind the air intake, is used to compress the incoming airflow;

[0016] A high-pressure compressor further compresses the air;

[0017] The combustion chamber mixes and burns high-pressure air with fuel to produce high-temperature, high-pressure combustion gas;

[0018] A high-pressure turbine uses the energy of high-temperature, high-pressure gas to drive a high-pressure compressor to rotate.

[0019] The low-pressure turbine utilizes the residual energy of the high-temperature, high-pressure gas to drive the fan and the low-pressure shaft to rotate.

[0020] The mixing chamber is used to mix the exhaust gases from the high-pressure turbine and the low-pressure turbine.

[0021] The nozzle discharges the mixed combustion gas to generate thrust;

[0022] The motor is mounted on the low-pressure shaft of the reference dual-rotor hybrid turbofan engine. It is used to extract the core engine shaft power and convert it into electrical energy to be delivered to the bypass fan in subsonic conditions, and to receive the electrical energy generated by the bypass fan and feed it back to the engine's low-pressure shaft in supersonic conditions.

[0023] The bypass fan, located in the third duct, is driven by a generator / motor to increase the bypass ratio, or in supersonic conditions, it is driven by excess airflow captured by the intake to generate electricity.

[0024] Electrical equipment receives electrical energy from generators / motors to operate;

[0025] The outer duct nozzle is used to expel airflow from the third duct.

[0026] In subsonic operation, the turbofan engine components operate normally, and the bypass fan is in electric drive mode. The motor on the low-pressure shaft extracts the core engine shaft power and converts it into electrical energy, which is then supplied to the bypass fan. The bypass fan is driven by the motor to increase the bypass ratio, ultimately achieving the goal of reducing fuel consumption and increasing engine thrust.

[0027] In supersonic operation, the turbofan engine components operate normally, the intake duct captures more airflow than the engine requires, and the air in the third bypass duct can be used to drive the fan to generate electricity. The electricity is then fed back to the low-pressure shaft of the engine through the motor, reducing the power required by the turbine, reducing the overflow resistance of the intake duct, increasing the engine's thrust, and reducing the fuel consumption rate.

[0028] The engine achieves dynamic adjustment of the bypass ratio by changing the operating state of the bypass fan, realizing an efficient matching design of thermodynamic variable cycle and power-to-electric conversion under multiple operating conditions.

[0029] The engine is an improvement on the existing dual-rotor hybrid turbofan engine and is suitable for supersonic aircraft with Mach numbers between 2 and 3.

[0030] The engine changes the bypass ratio and intake duct total pressure recovery coefficient through power-to-electricity conversion to adapt to engine-intake matching requirements, providing a new approach to solving engine-intake matching problems.

[0031] The bypass fan and motor work together to perform different functions in subsonic and supersonic states, in order to meet the power requirements of the aircraft under different flight conditions.

[0032] Compared with the prior art, the beneficial effects achieved by the technical solution of this invention are:

[0033] 1. This invention addresses the all-electric frame and variable performance cycle requirements of sixth-generation aircraft, making full use of the matching characteristics of the engine and air intake, and optimizing the thermodynamic cycle by utilizing the power-to-electric conversion pathway.

[0034] 2. This invention can provide additional electrical energy to the aircraft. In subsonic conditions, the motor extracts the core shaft power and delivers it to the bypass fan in the form of electrical energy. The bypass fan is driven by the motor to increase the bypass ratio, reduce fuel consumption, and increase engine thrust.

[0035] 3. This invention can improve aircraft installation performance and improve engine matching characteristics. At supersonic speeds, the intake flow rate is greater than the engine's required flow rate. The air in the third duct can be used to drive the fan to generate electricity, which is then sent to the motor to feed back the low-pressure shaft of the engine. This reduces the power required by the turbine, reduces the overflow resistance of the intake, increases the engine's installation thrust, and reduces the installation fuel consumption rate.

[0036] 4. This invention relies on the change of the working state of the bypass fan to realize the dynamic adjustment of the engine bypass ratio, realize the efficient matching design of thermodynamic "variable cycle" and power "conversion" under multiple working conditions, and improve the overall energy efficiency of the aircraft across the entire speed range.

[0037] 5. This invention utilizes the form of power "conversion" to adapt to the intake-engine matching requirements by changing the bypass ratio and the total pressure recovery coefficient of the intake duct, providing a new approach to solving the intake-engine matching problem.

[0038] 6. This invention is an improvement on the existing dual-rotor hybrid turbofan engine, with minimal modifications and high feasibility. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of an external bypass electric drive variable cycle turbine engine mechanism. Detailed Implementation

[0040] To make the technical problems, technical solutions, and beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the embodiments in the accompanying drawings.

[0041] This invention relates to an externally bypassed, electrically driven, variable-cycle turbofan engine, which is an improvement upon a benchmark dual-rotor hybrid turbofan engine. Based on the original engine, components such as a third bypass duct, an external bypass fan, an electric motor, and an external bypass nozzle are added to achieve dynamic adjustment of the engine's bypass ratio and efficient matching of power-to-electricity conversion. By fully utilizing the matching characteristics of the engine and inlet, and optimizing the thermodynamic cycle through power-to-electricity conversion, it provides additional electrical energy to the aircraft, achieving a highly efficient matching design of thermodynamic "variable cycle" and power-to-electricity "conversion" under multiple operating conditions. At subsonic speeds, the turbofan engine operates normally, and the electric motor extracts core shaft power and delivers it as electrical energy to the external bypass fan. The external bypass fan, driven by the electric motor, increases the bypass ratio, reduces fuel consumption, and increases engine thrust. At supersonic speeds, the inlet capture flow rate exceeds the engine's required flow rate. Air within the third bypass duct can be used to drive the fan to generate electricity, which is then delivered to the electric motor to replenish the engine's low-pressure shaft, thereby reducing the turbine's required power and lowering inlet overflow drag. This bypass electric drive variable cycle turbine engine, taking into account the impact of power-to-electricity conversion, reduces intake overflow resistance, increases engine installation thrust, and reduces installation fuel consumption. The design requires minimal modifications and is highly feasible.

[0042] like Figure 1 As shown, this bypass electric variable cycle turbofan engine scheme includes an intake duct 1, a fan 2, a high-pressure compressor 3, a combustion chamber 4, a high-pressure turbine 5, a low-pressure turbine 6, a mixing chamber 7, a nozzle 8, an electric motor 9, an bypass fan 10, electrical equipment 11, and an bypass nozzle 12. There are two outlets: nozzle 8 and bypass nozzle 12. The third duct is separately connected to the bypass nozzle 12. The airflow in the third duct passes through the bypass fan 10 and is then ejected from the bypass nozzle 12. The airflow in the reference dual-rotor mixed-emission turbofan engine passes through fan 2 and is split between the inner and outer ducts. After mixing in the mixing chamber 7, both are discharged from the nozzle 8.

[0043] The intake duct 1 is used to capture incoming airflow and provide sufficient airflow to the engine.

[0044] Fan 2 is located behind the air intake duct and performs preliminary compression on the incoming air to increase the air pressure.

[0045] The high-pressure compressor 3 further compresses the air to provide high-pressure air to the combustion chamber.

[0046] Combustion chamber 4 mixes and burns high-pressure air with fuel to produce high-temperature, high-pressure gas.

[0047] High-pressure turbine 5 utilizes the energy of high-temperature, high-pressure gas to drive the high-pressure compressor to rotate, thereby achieving energy conversion.

[0048] The low-pressure turbine 6 uses the residual energy of the high-temperature, high-pressure gas to drive the fan and low-pressure shaft to rotate, providing power to the engine.

[0049] The mixing chamber 7 mixes the gas discharged from the high-pressure turbine and the low-pressure turbine to make the gas temperature and pressure more uniform.

[0050] Nozzle 8 discharges the mixed gas, generating thrust.

[0051] Motor 9 is mounted on the low-pressure shaft and has a dual function. In subsonic conditions, it acts as a generator to extract power from the core engine shaft and convert it into electrical energy to supply the bypass fan; in supersonic conditions, it acts as a motor to receive electrical energy generated by the bypass fan and feed it back to the engine's low-pressure shaft.

[0052] The bypass fan 10 is located in the third duct and is driven by the motor 9. In subsonic conditions, it is driven by the motor to increase the bypass ratio; in supersonic conditions, it is driven by excess airflow captured by the intake duct 1 to generate electricity.

[0053] Electrical equipment 11 receives electrical energy from a motor to operate, such as the auxiliary power system of an aircraft.

[0054] The outer bypass nozzle 12 is used to expel the airflow from the third duct, thereby increasing the engine's thrust.

[0055] The benchmark dual-rotor mixed-emission turbofan engine includes a complete 1-8 structure (inlet 1, fan 2, high-pressure compressor 3, combustion chamber 4, high-pressure turbine 5, low-pressure turbine 6, mixing chamber 7, nozzle 8), with a third bypass extending behind the inlet 1. An outer bypass fan 10 is arranged in the third bypass, and the airflow in the bypass flows out through the outer bypass fan and a separate outer bypass nozzle 12.

[0056] The benchmark dual-rotor mixed-displacement turbofan engine includes a complete 1-8 structure. A generator / motor is installed on the low-pressure shaft of this structure. The motor is connected to the low-pressure shaft through a mechanical structure and exchanges electrical energy with the bypass fan, electrical equipment, etc.

[0057] ① indicates that when the engine is operating at subsonic speeds, the bypass fan is in electric drive mode, powered by the motor extracting power from the core shaft. ② indicates that when the engine is operating at supersonic speeds, the bypass fan is in generator mode, supplying power to the motor and other electrical equipment.

[0058] The working principle of this invention is as follows:

[0059] When the reference dual-rotor mixed-displacement turbofan engine components 1-8 are operating normally, when the aircraft is in a subsonic state, the motor 9 on the low-pressure shaft extracts the core shaft power and converts it into electrical energy to supply the bypass fan 10. The bypass fan 10 is driven by the motor 9 to increase the bypass ratio. The power-to-electricity conversion process is shown in ①, ultimately achieving the goal of reducing fuel consumption and increasing engine thrust. When the aircraft is in a supersonic state, the intake duct 1 captures a flow rate greater than the required flow rate of the dual-rotor mixed-displacement turbofan engine. The air in the third bypass duct can be used to drive the fan 10 to generate electricity, which is then fed back to the low-pressure shaft of the engine through the motor 9 in the form of electrical energy. This reduces the power required by the high-pressure turbine 5 and the low-pressure turbine 6, and reduces the overflow resistance of the intake duct. The excess electrical energy can also be supplied to the electrical equipment 11. The power-to-electricity conversion process is shown in ②. This scheme achieves the goal of reducing the overflow resistance of the intake duct, increasing the installed thrust of the engine, and reducing the installed fuel consumption rate by adjusting the intake / engine flow matching characteristics through the third bypass duct.

[0060] In the diagram, ① indicates that when the engine is operating at subsonic speeds, the bypass fan is in electric drive mode, powered by the motor extracting power from the core shaft. ② indicates that when the engine is operating at supersonic speeds, the bypass fan is in generator mode, supplying power to the motor and other electrical equipment.

[0061] The above embodiments are merely preferred embodiments of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A bypass electric drive variable cycle turbofan engine, comprising dual-rotor mixed-emission turbofan engine components: an intake duct, a fan, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a mixing chamber, and a nozzle, characterized in that... It also includes motors, bypass fans, electrical equipment, and bypass nozzles; The motor is mounted on the low-pressure shaft and is used to extract the core engine shaft power and convert it into electrical energy to be delivered to the bypass fan in subsonic conditions, and to receive the electrical energy generated by the bypass fan and feed it back to the engine's low-pressure shaft in supersonic conditions. The bypass fan is located within the extended third duct and is driven by the motor to increase the bypass ratio, or driven by excess airflow captured by the intake in supersonic conditions to generate electricity. The electrical equipment receives electrical energy from the motor to operate; The outer duct nozzle is used to expel airflow from the third duct. The motor enables power-to-electricity conversion and optimizes the thermodynamic cycle. The bypass fan and motor work together to adjust engine performance in subsonic and supersonic states by driving the bypass fan and receiving the electrical energy generated by the bypass fan, respectively, to achieve different functions and meet the power requirements of the aircraft under different flight conditions.

2. The bypass electric drive variable cycle turbofan engine according to claim 1, characterized in that, The motor is connected to the low-voltage shaft via a mechanical structure and exchanges electrical energy with the external fan and electrical equipment.

3. The bypass electric drive variable cycle turbofan engine according to claim 1, characterized in that, In subsonic operation, the components of the dual-rotor hybrid turbofan engine operate normally, and the bypass fan is in electric drive mode. The motor extracts the core shaft power and converts it into electrical energy to be delivered to the bypass fan. The bypass fan is driven by the motor to increase the bypass ratio, reduce fuel consumption, and increase engine thrust.

4. The bypass electric drive variable cycle turbofan engine according to claim 1, characterized in that, In supersonic operation, the dual-rotor mixed-flow turbofan engine components operate normally. The intake duct captures a flow rate greater than the engine's required flow rate. The air in the third bypass duct is used to drive the fan to generate electricity. The motor receives electrical energy and feeds it back to the engine's low-pressure shaft, reducing the turbine's required power, reducing the intake duct overflow resistance, increasing the engine's thrust, and reducing the engine's fuel consumption rate.

5. A design method for an externally bypass electric-driven variable-cycle turbofan engine, characterized in that... Includes the following steps: 1) Determine the benchmark engine: Select an existing dual-rotor mixed-displacement turbofan engine as the benchmark. The dual-rotor mixed-displacement turbofan engine includes an intake, fan, high-pressure compressor, combustion chamber, high-pressure turbine, low-pressure turbine, mixing chamber, and nozzle. 2) Add an electric motor and an external bypass fan: Add an electric motor to the low-pressure shaft of the benchmark dual-rotor mixed-displacement turbofan engine. The electric motor and the low-pressure shaft are connected by a mechanical structure. Extend a third bypass duct behind the intake duct and arrange an external bypass fan in the third bypass duct. Ensure that electrical energy can be exchanged between the motor and the external fan; 3) Design of the duct fan and nozzle: Design appropriate fan size and speed according to the working requirements of the duct fan; design a separate duct nozzle to discharge the airflow in the third duct. 4) Thermodynamic cycle and power conversion design: Design thermodynamic cycle parameters to ensure that the engine can maintain high efficiency under different operating conditions; The design employs a power-to-electricity conversion strategy to extract core engine shaft power and convert it into electrical energy to supply the bypass fan in subsonic conditions. In supersonic conditions, it receives electrical energy generated by the bypass fan and feeds it back to the engine's low-pressure shaft, thereby enabling coordinated operation of the motor and bypass fan in both subsonic and supersonic conditions.

6. The design method of an externally bypass electric-driven variable-cycle turbofan engine according to claim 5, characterized in that, In step 4), the bypass ratio of the engine is dynamically adjusted by changing the working state of the bypass fan, thereby achieving an efficient matching design of thermodynamic variable cycle and power-electric conversion under multiple operating conditions.

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