Propulsion power optimization system for blade tip jet self-driven ducted fan

Abstract

The invention discloses a propeller tip jet self-driven ducted fan propulsion power optimization system, which is applied to the technical field of aircraft power technologies, and comprises a multi-mode coupling driving module, which adopts a core engine air entraining and blade tip turbine hybrid driving mode, and designs a three-stage expansion jet pipe consisting of a contraction section, a throat part and an expansion section, the method is used for wide-range adjustment of Mach number; the flow channel optimization design module comprises a blade inner pipeline with the curvature radius controlled within a preset range, a shape maintaining nozzle of a microgroove array structure and a vector exhaust device of an integrated intelligent guide blade. And the system parameter optimization module is used for determining a mutual relation among physical quantities in the system by establishing a gas dynamics-thermodynamics-structural mechanics coupling equation, and optimizing structural parameters and working parameters of the system through a genetic algorithm by taking a thrust / oil consumption ratio as a target function. According to the invention, the key technical bottleneck of the existing blade tip jet driving system in the vertical take-off and landing power field is broken through, and the system performance is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft power technology, and particularly relates to an optimized system for the propulsion power of a tip-jet self-driven ducted fan. Background Art

[0002] In the modern aviation field, vertical takeoff and landing (VTOL) aircraft have shown extremely broad application prospects in both military and civilian fields due to their unique advantages. Militarily, it can achieve rapid takeoff and landing in narrow spaces, such as performing tasks in environments like aircraft carrier decks and mountainous simple sites, providing high flexibility and mobility for combat operations, and can be used for various tasks such as reconnaissance, rescue, and fire support. In the civilian field, VTOL aircraft can be applied to urban logistics distribution to solve the last-mile distribution problem; in emergency medical rescue, it can quickly reach the accident scene to transport the wounded; it can also be used for tasks such as geographical mapping and power line inspection, improving work efficiency and safety.

[0003] However, there are many problems in the power systems of traditional VTOL aircraft. For example, in traditional turbofan engines, the improvement of thrust is restricted by their own structure and working principle, and it is difficult to meet the high-thrust requirements of the aircraft during vertical takeoff and landing and high-speed flight. In terms of fuel consumption, in the vertical takeoff and landing stage of the traditional power system, since it needs to overcome gravity to achieve vertical ascent, the engine consumes a large amount of fuel, resulting in too high fuel consumption. This not only increases the operating cost but also limits the range and endurance of the aircraft. At the same time, the structure of the traditional power system is usually relatively complex, including many mechanical components and transmission devices. This not only increases the weight and volume of the system but also raises the manufacturing and maintenance costs, and reduces the reliability and stability of the system.

[0004] The emergence of the tip-jet self-driven ducted fan technology provides a new idea for solving the above problems. This technology extracts high-pressure gas from the core engine and transports it to the tips of the ducted fan blades. The reaction force generated by the tip jets is used to drive the blades to rotate, thus achieving the self-driving of the fan. This unique working method breaks through the design limitations of traditional turbofan engines and has significant advantages. On the one hand, it can effectively amplify the thrust of the core engine by optimizing the parameters of the tip jets and the design of the ducted fan, providing stronger power support for the aircraft. On the other hand, since the energy loss of traditional mechanical transmission components is reduced during its working process, the propulsion efficiency of the system is improved, thereby reducing fuel consumption and increasing the range and endurance of the aircraft. In addition, the tip-jet self-driven ducted fan technology also has the characteristics of relatively simple and compact structure, reducing the number and complexity of mechanical components, lowering the manufacturing and maintenance costs, and improving the reliability and stability of the system.

[0005] Although the tip jet drive system shows great potential in the field of vertical takeoff and landing power, there are still some key technical bottlenecks at present, which seriously restrict the further improvement of its performance and wide application. In terms of thrust amplification ability, although the existing system can improve the thrust to a certain extent, there is still much room for improvement compared with the actual needs of the aircraft. The tip turbine leakage flow is also one of the main reasons for the decline of system efficiency. During the operation of the tip turbine, due to the gap between the blade and the casing, part of the high-pressure gas will leak out from the gap under the action of the pressure difference, forming a leakage flow. This leakage flow will not only take away part of the energy of the high-pressure gas, resulting in a reduction in the output power of the tip turbine, but also produce complex flow phenomena on the blade surface, increasing the flow loss and further reducing the system efficiency. Research shows that the efficiency loss caused by the tip turbine leakage flow can reach 8-12%, which is a problem that cannot be ignored for the tip jet drive system pursuing high-efficiency performance. The slow response speed of vector thrust regulation is also an important problem faced by the current tip jet drive system. During the flight of the aircraft, it is necessary to quickly and accurately adjust the direction and magnitude of the vector thrust according to the flight attitude and mission requirements to achieve stable flight and flexible maneuvering. However, the existing vector thrust regulation mechanisms usually have problems such as complex structure and large inertia, resulting in a slow response speed, and the typical value is greater than 200ms. Such a response speed cannot meet the control requirements of the aircraft under high-speed flight and complex maneuvers, restricting the mobility and maneuverability of the aircraft. At the same time, in the high-temperature and high-pressure environment, the risk of seal failure of the tip jet drive system is relatively high. During the operation of the tip jet drive system, the tip part bears the action of high-temperature and high-pressure gas, posing extremely high requirements on the sealing device. If the performance of the sealing device is not good or problems such as wear and aging occur during long-term use, it will lead to seal failure and leakage of high-pressure gas, which will not only reduce the system performance but also may cause safety accidents. In addition, the high-temperature and high-pressure environment will also affect the material properties of the system, accelerating the fatigue and corrosion of the materials, further increasing the risk of seal failure.

[0006] Therefore, how to provide a tip jet self-driven ducted fan propulsion power optimization system that can break through the above-mentioned key technical bottlenecks of the current tip jet drive system in the field of vertical takeoff and landing power and effectively improve the system performance is an urgent problem for those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention proposes a tip jet self-driven ducted fan propulsion power optimization system.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A tip jet self-driven ducted fan propulsion power optimization system, comprising: a multi-modal coupling drive module, a flow path optimization design module, a sealing and lubrication system, and a system parameter optimization module;

[0010] The multi-modal coupling drive module adopts a hybrid drive mode of core engine bleed air + tip turbine, and designs a three-stage expansion nozzle composed of a contraction section, a throat section, and an expansion section for wide-range adjustment of the Mach number; during takeoff and hover phases, the core engine bleed air drive mode plays a dominant role; during cruise phase, the tip turbine drive mode plays a dominant role;

[0011] The flow path optimization design module includes: an inner blade pipeline with a curvature radius controlled within a preset range, a conformal nozzle with a micro-groove array structure, and a vector exhaust device integrated with intelligent guide vanes;

[0012] The sealing and lubrication system adopts a combination of double-end face labyrinth seals + magnetic bearings; the double-end face labyrinth seals form tortuous sealing channels by arranging multiple annular sealing teeth between the shaft and the casing, and use the throttling effect and expansion cavities to prevent gas leakage; the magnetic bearings suspend the rotor by magnetic force to avoid energy loss and wear caused by contact friction;

[0013] The system parameter optimization module determines the mutual relationship between physical quantities in the system by establishing an aerodynamics-thermodynamics-structural mechanics coupling equation, takes the thrust / fuel consumption ratio as the objective function, and optimizes the structural parameters and working parameters of the system through a genetic algorithm.

[0014] Optionally, the wide-range adjustment range of the three-stage expansion nozzle for the Mach number is 0.5 - 1.2; under low Mach number conditions, the contraction section of the three-stage expansion nozzle can effectively accelerate the airflow to the speed of sound, the throat section ensures that the airflow passes through under critical conditions, and the expansion section further accelerates the airflow to the required Mach number; under high Mach number conditions, the design of the contraction section and the throat section enables the airflow to quickly reach supersonic speed, and the expansion section realizes uniform expansion of the airflow through an optimized profile to avoid shock waves and flow separation phenomena.

[0015] Optionally, the curvature radius of the inner blade pipeline is controlled to be greater than three times the pipeline diameter, which is realized by a design scheme based on sinusoidal curve transition.

[0016] Optionally, the micro-groove depth of the conformal nozzle is controlled at 0.2 mm.

[0017] Optionally, the response time of the intelligent guide vanes is controlled to be less than 50 ms.

[0018] Optionally, the sealing and lubrication system further includes: a high-temperature resistant composite material coating applied to key components of the system; the key components include: blades, tip turbines, and sealing devices; the high-temperature resistant composite material coating includes: a ceramic matrix composite material coating and a metal matrix composite material coating.

[0019] Optionally, establish an aerodynamics-thermodynamics-structural mechanics coupling equation, specifically:

[0020] Establish an aerodynamics model considering the airflow characteristics during the intake, compression, and jet processes of the ducted fan, a thermodynamics equilibrium equation considering the energy conversion and heat transfer during the bleed air of the core engine and the driving process of the tip turbine, and a structural mechanics model considering the mechanical properties of the blades under high-speed rotation and high-temperature and high-pressure environments.

[0021] Optionally, the aerodynamics model considering the airflow characteristics during the intake, compression, and jet processes of the ducted fan is established based on the Reynolds-averaged Navier-Stokes equation.

[0022] Optionally, optimize the structural parameters and working parameters of the system through a genetic algorithm, specifically:

[0023] Encode the solution space of the system and represent the parameters of the system as chromosomes;

[0024] Randomly generate a certain number of individuals to form an initial population, and calculate the fitness value of each individual according to the objective function;

[0025] Use the roulette wheel selection method to select excellent individuals into the next generation, generate new individuals through crossover and mutation operations, continuously evolve the population, and end the algorithm until the preset number of evolution generations is reached or other termination conditions are met;

[0026] The individual with the highest fitness value in the population is the optimized system parameter.

[0027] Optionally, the structural parameters of the system include: blade shape, size, and duct diameter; the working parameters of the system include: jet pressure, temperature, and flow rate.

[0028] As can be seen from the above technical solutions, compared with the prior art, the present invention proposes a tip jet self-driven ducted fan propulsion power optimization system. By adopting the core engine air extraction + tip turbine hybrid drive mode and combining with the three-stage expansion nozzle design, a wide range of regulation from Mach 0.5 to 1.2 is achieved, improving the power output and efficiency of the system. Through the optimized design of the internal pipeline of the blade, the conformal nozzle and the flow path of the vector exhaust device, the flow loss is reduced, and the jet efficiency and vector control accuracy are improved. By adopting the combination of double-end face labyrinth seal + magnetic suspension bearing and applying high-temperature resistant composite material coating, the seal failure and lubrication problems in the high-temperature and high-pressure environment are effectively solved, and the reliability and stability of the system are improved. By establishing the coupled equations of aerodynamics - thermodynamics - structural mechanics and taking the thrust / fuel consumption ratio as the objective function, the structural parameters and working parameters of the system are optimized through the genetic algorithm, further reducing the air flow loss, improving the propulsion efficiency of the system, and enhancing the strength and stability of the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0030] Figure 1 It is a schematic structural diagram of the system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Embodiment 1:

[0033] Embodiment 1 of the present invention discloses a tip jet self-driven ducted fan propulsion power optimization system, as Figure 1 shown, including: a multi-modal coupling drive module, a flow path optimization design module, a sealing and lubrication system, and a system parameter optimization module;

[0034] In view of the limitations of the traditional tip-jet self-powered ducted fan propulsion system in the driving mode, the present invention designs a multi-modal coupling drive module, adopting a hybrid drive mode of core engine bleed air + tip turbine to achieve more efficient power output and more flexible working mode switching, and designs a three-stage expansion nozzle composed of a contraction section, a throat section and an expansion section for wide-range regulation of the Mach number.

[0035] In the hybrid drive mode of core engine bleed air + tip turbine, the core engine serves as the energy source of the entire power system, and conveys the generated high-pressure gas to the tip turbine through the air duct. The tip turbine, as an energy conversion device, utilizes the energy of the high-pressure gas to drive the blade to rotate, thereby realizing the self-driving of the ducted fan. During the takeoff and hover stages, the core engine bleed air drive mode plays a leading role. At this time, the aircraft needs to overcome gravity to achieve vertical ascent, and has a large demand for thrust. The core engine bleed air can provide a large thrust, enabling the aircraft to take off and hover quickly and stably. During the cruise stage, the tip turbine drive mode plays a leading role. At this time, the aircraft needs to maintain a stable flight speed and has a high requirement for efficiency. The tip turbine drive mode can more effectively convert the energy of the high-pressure gas into mechanical energy, improve the propulsion efficiency of the system and reduce fuel consumption.

[0036] Moreover, in order to achieve wide-range regulation of the Mach number from 0.5 to 1.2, a three-stage expansion nozzle composed of a contraction section, a throat section and an expansion section is designed. By ingeniously designing the shapes and sizes of each section, precise control and efficient expansion of the air flow can be achieved. Under low Mach number conditions, such as when the Mach number is 0.5, the contraction section of the three-stage expansion nozzle can effectively accelerate the air flow to the speed of sound, the throat section ensures that the air flow passes through in a critical state, and the expansion section further accelerates the air flow to the required Mach number; under high Mach number conditions, such as when the Mach number is 1.2, the designs of the contraction section and the throat section can make the air flow reach supersonic speed quickly, and the expansion section realizes uniform expansion of the air flow through an optimized profile, avoiding shock waves and flow separation phenomena, thus ensuring the efficient operation of the nozzle.

[0037] The optimized design of the flow path is also crucial for improving the performance of the tip-jet self-powered ducted fan propulsion system. Therefore, the present invention starts from three key components, namely the internal pipeline of the blade, the conformal nozzle and the vector exhaust device, and conducts a comprehensive optimized design of the flow path. The flow path optimized design module includes: the internal pipeline of the blade with the curvature radius controlled within a preset range, the conformal nozzle adopting a microgroove array structure, and the vector exhaust device integrated with intelligent guide vanes.

[0038] The internal pipeline in the blade is an important channel for high-pressure gas transmission, and its design directly affects the gas flow performance and energy loss. To reduce the flow loss, based on the design scheme of sine curve transition, the present invention controls the curvature radius of the internal pipeline in the blade to be greater than three times the pipeline diameter. The sine curve transition can make the gas flow more smoothly in the pipeline, reducing the local resistance and energy loss caused by sharp turns. Through numerical simulation and experimental verification, the internal pipeline in the blade with sine curve transition can reduce the gas flow loss by 15 - 20%, thereby improving the system efficiency.

[0039] As a key component of the tip jet, the conformal nozzle's performance directly affects the jet efficiency and thrust. To improve the performance of the conformal nozzle, the present invention adopts a microgroove array structure and controls the microgroove depth to be 0.2 mm. The microgroove array structure can increase the surface roughness of the nozzle, promoting the turbulent mixing of gas, thereby improving the jet efficiency and thrust. Experimental results show that the conformal nozzle with a microgroove array structure can increase the jet efficiency by 10 - 15% and the thrust by 8 - 12%.

[0040] By adopting the microgroove array structure and optimized blade design, the tip leakage flow is effectively controlled, and the system efficiency is increased by 9.2%. The microgroove array structure can form minute airflow disturbances on the blade surface, suppressing the generation of leakage flow and reducing energy loss; the optimized blade design makes the airflow flow more smoothly on the blade surface by adjusting the blade shape, size, and angle, improving the aerodynamic performance of the blade. The application of these technologies enables the system to generate greater thrust under the same input energy, improving the propulsion efficiency of the system.

[0041] The vector exhaust device is a key component for realizing the vector control of the aircraft, and its response speed and control accuracy directly affect the maneuverability and controllability of the aircraft. To improve the performance of the vector exhaust device, the present invention integrates intelligent deflector blades and controls the response time to be less than 50 ms. The intelligent deflector blades can utilize the intelligent vector thrust control algorithm to quickly and accurately adjust the exhaust direction according to the flight attitude and control instructions of the aircraft, achieving precise control of the thrust direction. Through experimental verification, the vector exhaust device integrated with intelligent deflector blades can significantly improve the maneuverability and controllability of the aircraft, meeting the control requirements of the aircraft in complex flight environments.

[0042] By utilizing the intelligent vector thrust control algorithm to monitor and analyze the flight state and attitude of the aircraft in real time, it is possible to quickly and accurately adjust the direction and magnitude of the vector thrust, increasing the response speed of the aircraft by 75%. Compared with the traditional vector thrust control algorithm, the intelligent vector thrust control algorithm has higher control accuracy and faster response speed, and can better meet the control requirements of the aircraft in complex flight environments. For example, when the aircraft performs rapid maneuvers, the intelligent vector thrust control algorithm can quickly adjust the thrust direction, enabling the aircraft to respond quickly and achieve flexible flight attitude changes; when the aircraft hovers and lands, it can precisely control the thrust magnitude to ensure the stability and safety of the aircraft.

[0043] In the tip jet self-driven ducted fan propulsion power system, the sealing and lubrication system is crucial for ensuring the normal operation of the system. Therefore, the sealing and lubrication system of the present invention adopts a design scheme combining double-end face labyrinth seals and magnetic levitation bearings, and at the same time applies a high-temperature resistant composite material coating to improve the reliability and stability of the system in high-temperature and high-pressure environments.

[0044] The combination of double-end face labyrinth seals and magnetic levitation bearings; the double-end face labyrinth seal forms a tortuous sealing channel by setting multiple annular sealing teeth between the shaft and the casing, and uses the throttling effect and expansion cavity to prevent gas leakage. This sealing method has the advantages of simple structure, high reliability, good sealing effect, etc., and can effectively reduce the tip turbine leakage flow and improve the efficiency of the system. At the same time, in high-temperature and high-pressure environments, ordinary sealing materials are prone to problems such as wear and aging, resulting in seal failure. Therefore, the present invention selects high-temperature resistant and wear-resistant sealing materials, such as ceramic matrix composites and superalloys, to improve the performance and reliability of the sealing system.

[0045] The magnetic levitation bearing suspends the rotor by magnetic force, avoiding the energy loss and wear caused by contact friction in traditional mechanical bearings. The magnetic levitation bearing has the advantages of non-contact, non-wear, high precision, high rotational speed, etc., and can improve the efficiency and reliability of the system. At the same time, the application of the magnetic levitation bearing can also reduce the vibration and noise of the system, improving the comfort and safety of the aircraft. In high-temperature and high-pressure environments, the performance of the magnetic levitation bearing will be affected to a certain extent. Therefore, the present invention optimizes the structure and control system of the magnetic levitation bearing, and adopts high-temperature resistant magnetic materials and heat dissipation structures to ensure the normal operation of the magnetic levitation bearing in high-temperature and high-pressure environments.

[0046] The high-temperature resistant composite material coating can form a protective film under high-temperature and high-pressure environments, protecting system components from the effects of high temperature, high pressure, corrosion and other factors. This invention adopts high-temperature resistant composite material coatings such as ceramic matrix composite material coatings and metal matrix composite material coatings, and applies them to key components of the system, such as propeller blades, tip turbines, sealing devices, etc. These coatings have the advantages of high temperature resistance, wear resistance, corrosion resistance, etc., and can effectively improve the performance and service life of system components. Experimental results show that the service life of system components with high-temperature resistant composite material coatings can be increased by 2-3 times under high-temperature and high-pressure environments.

[0047] In order to achieve the optimal design of the tip jet self-driven ducted fan propulsion power system, this invention designs a system parameter optimization module. By establishing the coupled equations of aerodynamics-thermodynamics-structural mechanics, the performance of the system under different working conditions can be comprehensively considered. Through in-depth analysis of aerodynamics, thermodynamics and structural mechanics, the mutual relationships between physical quantities in the system are determined, providing a solid theoretical basis for subsequent optimal design. Taking the thrust / fuel consumption ratio as the objective function, the structural parameters and working parameters of the system are optimized through genetic algorithms.

[0048] The coupled equations of aerodynamics-thermodynamics-structural mechanics are established as follows:

[0049] An aerodynamic model considering the airflow characteristics during the intake, compression and jet processes of the ducted fan is established to accurately describe the movement law of the airflow in the system. A thermodynamic equilibrium equation considering the energy conversion and heat transfer during the core engine air extraction and tip turbine drive processes is established to analyze the energy utilization efficiency and thermal management performance of the system. A structural mechanics model considering the mechanical properties of the propeller blade under high-speed rotation and high-temperature and high-pressure environments is established to evaluate the strength and stability of the propeller blade.

[0050] The aerodynamic model considering the airflow characteristics during the intake, compression and jet processes of the ducted fan is established based on the Reynolds-averaged Navier-Stokes equations.

[0051] Genetic algorithm is an optimization algorithm based on the principle of biological evolution, with advantages such as strong global search ability and good robustness. This invention realizes the optimal matching of system parameters through genetic algorithms to improve the thrust performance and fuel economy of the system. The structural parameters and working parameters of the system are optimized through genetic algorithms as follows:

[0052] Encode the solution space of the system, and represent the parameters of the system as chromosomes;

[0053] Randomly generate a certain number of individuals to form an initial population, and calculate the fitness value of each individual according to the objective function;

[0054] The roulette wheel selection method is used to select excellent individuals into the next generation. New individuals are generated through crossover and mutation operations, and the population is continuously evolved until the preset number of generations or other termination conditions are met, at which point the algorithm ends;

[0055] The individual with the highest fitness value in the population is the optimized system parameter.

[0056] The structural parameters of the system include: blade shape, size, and duct diameter; the operating parameters of the system include: jet pressure, temperature, and flow rate.

[0057] To verify the effectiveness of the system parameter optimization and matching design based on the genetic algorithm, a method combining CFD simulation and structural analysis is adopted. First, the ANSYS Fluent software is used to simulate the flow field of the system to verify the uniformity of the flow field. During the simulation, the standard k-epsilon turbulence model is adopted, and the airflow under different working conditions is numerically simulated. It can be seen from the simulation results that after the optimized design, the uniformity of the flow field of the system has been significantly improved, the turbulence intensity is less than 5%, effectively reducing the airflow loss and improving the propulsion efficiency of the system.

[0058] At the same time, the ABAQUS software is used to analyze the structure of the blade to check the stress distribution of the blade. During the analysis, the mechanical properties of the blade under high-speed rotation and high-temperature and high-pressure environments are considered, and the blade stress under different working conditions is calculated. It can be seen from the analysis results that after the optimized design, the stress distribution of the blade is more uniform, the safety factor is greater than 1.8, meeting the design requirements, and effectively improving the strength and stability of the blade.

[0059] The improved tip jet self-powered ducted fan propulsion system is comprehensively tested and analyzed. Compared with the traditional scheme, various performance indicators have been significantly improved, as follows:

[0060] In terms of the thrust-to-weight ratio, the improved system has been increased to 1.65, while the traditional scheme is only 1.2. The increase in the thrust-to-weight ratio means that the aircraft can obtain greater thrust at the same weight, which will significantly improve the acceleration performance, climb rate, and payload capacity of the aircraft. For example, during vertical takeoff and landing, a higher thrust-to-weight ratio can enable the aircraft to reach the cruise altitude faster and shorten the takeoff time; when performing tasks, it can carry more equipment and supplies, improving the task execution efficiency.

[0061] Hover fuel consumption is one of the important indicators for measuring the performance of vertical takeoff and landing aircraft. The hover fuel consumption of the improved system has been reduced by 28%, reaching 0.65 kg / N·h. This improvement benefits from the optimized design of the system in multiple aspects such as aerodynamics, thermodynamics, and structural mechanics. By optimizing the flow channel design, air flow losses are reduced and jet efficiency is improved; by adopting an efficient energy conversion mechanism, the energy utilization in the processes of core engine air extraction and tip turbine drive is more sufficient. The reduction of hover fuel consumption not only reduces the operation cost of the aircraft, but also extends the endurance time of the aircraft, enabling it to perform tasks for a longer time.

[0062] System complexity is a key factor affecting the reliability and maintenance cost of the aircraft. The system complexity index of the improved system has decreased by 40%. This mainly benefits from the adoption of an innovative multi-modal coupling drive structure, which reduces the complex mechanical transmission components in the traditional power system; the optimized flow channel design makes the structure of the system more compact and reasonable; at the same time, an advanced sealing and lubrication system is adopted to improve the reliability and stability of the system and reduce the maintenance requirements. The reduction of system complexity makes the manufacturing and maintenance of the aircraft easier, improving the availability and economy of the aircraft.

[0063] The embodiment of the present invention discloses an optimized system for the propulsion power of a tip jet self-driven ducted fan. By adopting a core engine air extraction + tip turbine hybrid drive mode and combining with a three-stage expansion nozzle design, a wide range of regulation from Mach 0.5 to 1.2 is achieved, enhancing the power output and efficiency of the system. Through the optimized design of the flow channels of the inner pipeline of the blade, the conformal nozzle, and the vector exhaust device, flow losses are reduced, and jet efficiency and vector control accuracy are improved. By adopting a combination of double-end face labyrinth seals + magnetic levitation bearings and applying a high-temperature resistant composite material coating, the problems of seal failure and lubrication in high-temperature and high-pressure environments are effectively solved, improving the reliability and stability of the system. By establishing an aerodynamics-thermodynamics-structural mechanics coupling equation and using the thrust / fuel consumption ratio as the objective function, the structural parameters and working parameters of the system are optimized through a genetic algorithm, further reducing air flow losses, improving the propulsion efficiency of the system, and enhancing the strength and stability of the blade.

[0064] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and reference can be made to the description in the method part for related parts.

[0065] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tip jet self-driven ducted fan propulsion power optimization system, characterized in that, Including: A multimodal coupling drive module, a flow channel optimization design module, a sealing and lubrication system, and a system parameter optimization module; The multimodal coupling drive module adopts a hybrid drive mode of core engine bleed air + tip turbine, and designs a three-stage expansion nozzle composed of a contraction section, a throat, and a diffuser section for wide-range adjustment of Mach number; during takeoff and hover phases, the core engine bleed air drive mode plays a dominant role; During the cruise phase, the tip turbine drive mode plays a dominant role; The flow channel optimization design module includes: an internal blade pipeline with a curvature radius controlled within a preset range, a conformal nozzle with a microgroove array structure, and a vector exhaust device integrated with intelligent guide vanes; The sealing and lubrication system adopts a combination of double-end face labyrinth seals + magnetic bearings; the double-end face labyrinth seals form a tortuous sealing channel by setting multiple annular sealing teeth between the shaft and the casing, and use the throttling effect and expansion cavity to prevent gas leakage; the magnetic bearings suspend the rotor by magnetic force to avoid energy loss and wear caused by contact friction; The system parameter optimization module determines the mutual relationship between physical quantities in the system by establishing an aerodynamics-thermodynamics-structural mechanics coupling equation, takes the thrust / fuel consumption ratio as the objective function, and optimizes the structural parameters and working parameters of the system through a genetic algorithm.

2. The optimized system for the propulsion power of a ducted fan with tip jet self-drive according to claim 1, wherein The wide-range adjustment range of the Mach number of the three-stage expansion nozzle is 0.5 - 1.2; under low Mach number conditions, the contraction section of the three-stage expansion nozzle can effectively accelerate the air flow to the speed of sound, the throat ensures that the air flow passes through in a critical state, and the diffuser section further accelerates the air flow to the required Mach number; under high Mach number conditions, the design of the contraction section and the throat enables the air flow to quickly reach supersonic speed, and the diffuser section realizes uniform expansion of the air flow through an optimized profile to avoid shock waves and flow separation phenomena.

3. A tip jet self-driven ducted fan propulsion power optimization system according to claim 1, characterized in that, The curvature radius of the internal blade pipeline is controlled to be greater than three times the pipeline diameter, which is achieved by a design scheme based on sinusoidal curve transition.

4. A tip jet self-driven ducted fan propulsion power optimization system according to claim 1, characterized in that The microgroove depth of the conformal nozzle is controlled at 0.2 mm.

5. The optimized system for the propulsion power of a ducted fan with tip jet self-drive according to claim 1, characterized in that, The response time of the intelligent guide vanes is controlled to be less than 50 ms.

6. The optimized system for the propulsion power of a ducted fan with tip jet self-drive according to claim 1, wherein The sealing and lubrication system also includes: a high-temperature resistant composite material coating applied to key components of the system; the key components include: blades, tip turbines, and sealing devices; the high-temperature resistant composite material coating includes: ceramic matrix composite material coating, metal matrix composite material coating.

7. A tip jet self-driven ducted fan propulsion power optimization system according to claim 1, wherein, Establishing the aerodynamics-thermodynamics-structural mechanics coupling equation specifically is: Establishing an aerodynamics model considering the air flow characteristics during the intake, compression, and jet processes of the ducted fan, a thermodynamics equilibrium equation considering the energy conversion and heat transfer during the core engine bleed air and tip turbine drive processes, and a structural mechanics model considering the mechanical properties of the blades under high-speed rotation and high-temperature and high-pressure environments.

8. A tip jet self-driven ducted fan propulsion power optimization system according to claim 7, wherein The aerodynamics model considering the air flow characteristics during the intake, compression, and jet processes of the ducted fan is established based on the Reynolds-averaged Navier-Stokes equation.

9. The optimized system for the propulsion power of a tip jet self-driven ducted fan according to claim 1, characterized in that, Optimizing the structural parameters and working parameters of the system through a genetic algorithm specifically is: Encode the solution space of the system and represent the parameters of the system as chromosomes; Randomly generate a certain number of individuals to form an initial population, and calculate the fitness value of each individual according to the objective function; Use the roulette wheel selection method to select excellent individuals into the next generation, generate new individuals through crossover and mutation operations, and continuously evolve the population until the preset number of evolutionary generations is reached or other termination conditions are met, then the algorithm ends; The individual with the highest fitness value in the population is the optimized system parameter.

10. The optimized system for the propulsion power of a tip-jet self-driven ducted fan according to claim 1, characterized in that, The structural parameters of the system include: blade shape, size, duct diameter; the working parameters of the system include: jet pressure, temperature, flow rate.

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