A high-bypass-ratio aero-engine front power extraction method and system

Abstract

This invention provides a method and system for extracting front-end power from a high-bypass turbofan engine, including a low-pressure rotor front-end power extraction subsystem and a support structure. The support structure includes a coaxial outer casing and an inner casing. The outer casing is connected to a fan casing. The front end of the inner casing is connected to the outer casing via a load-bearing support plate. The rear end of the inner casing overlaps with the low-pressure rotor blade disk, and the generator is assembled in the inner cavity of the front end of the inner casing. The method includes a front-end power extraction method design step and a front-end power extraction system design step. The front-end power extraction method design step includes: the extraction and allocation of high-pressure rotor front-end power and low-pressure rotor front-end power. The method and system designed in this invention extract low-pressure rotor power through a front-end power extraction method, ensuring the power demand of the aero-engine while guaranteeing compressor margin, filling a gap in the industry and having significant guiding significance.

Description

Technical Field

[0001] This invention belongs to the field of aero-engines and relates to engine power extraction design technology, specifically a method and system for extracting the front power of a high bypass ratio aero-engine. Background Technology

[0002] With the development of communication technology, computer technology, and airborne laser weapons, aircraft are increasingly demanding more electrical power, which is causing aero engines to face an ever-increasing demand for power extraction (i.e., the energy consumed by the engine to drive the generator to produce electrical energy).

[0003] For example, when an aircraft is performing a flight mission at high altitude, the power generated by the turbine decreases, which reduces the engine's power extraction capability. If high power extraction continues at this time, it will lead to insufficient engine surge margin, affecting flight safety. To ensure flight safety, the high power extraction requirements of the aircraft cannot be met. Another example is that modern aero engines mainly adopt a dual-rotor structure, with engine power extraction primarily coming from the high-pressure rotor. In small and medium thrust engines operating at high altitudes, because the power generated by the turbine is small, extracting sufficient power from the high-pressure rotor will significantly reduce the compressor's margin.

[0004] At the same time, there is currently no method for extracting low-pressure power from the front of a high bypass ratio aero-engines. Summary of the Invention

[0005] The purpose of this invention is to disclose a method and system for extracting the front power of a high bypass ratio aero-engine. This method and system can meet the power requirements of an aircraft when flight safety cannot be guaranteed, and can also solve the problems of installation and operational reliability of the power extraction system.

[0006] The technical solution to achieve the purpose of the invention is as follows:

[0007] In a first aspect, the present invention provides a high bypass ratio aero-engine front power extraction system, including a low-pressure rotor front power extraction subsystem, wherein the low-pressure rotor front power extraction subsystem includes a support structure and a front power transmission device.

[0008] The supporting structure includes a coaxial outer casing and an inner casing. The outer casing is connected to the fan casing, and the front end of the inner casing is connected to the outer casing via a load-bearing support plate. The rear end of the inner casing overlaps with the low-pressure rotor blades, and a generator is installed in the inner cavity of the front end of the inner casing. Because the low-pressure rotor operates at a low speed and has low power extraction, the generator is relatively heavy and large. Therefore, to ensure reliable installation and power transmission, the generator is installed at the load-bearing support plate. Furthermore, the axial distance between the load-bearing support plate and the fan rotor blades is relatively large, resulting in a long power transmission device between the generator and the low-pressure rotor.

[0009] Furthermore, the axial distance between the load-bearing support plate and the fan rotor blades is 1 to 2 times the chord length of the fan rotor blades to ensure the aerodynamic stability of the fan rotor.

[0010] Furthermore, the front power transmission device is located in the inner cavity at the rear end of the inner casing, and one end of the front power transmission device is connected to the generator, while the other end is connected to the low-pressure rotor disk.

[0011] Furthermore, the pre-power transmission device is located between the low-pressure rotor and the generator. To address the installation and transmission stability issues caused by the long length of the transmission device, a pre-power transmission system is designed. The pre-power transmission system includes drive shafts connected in sequence. One end of the drive shaft is mounted on the low-pressure rotor blade disk, and the other end is connected to the power output shaft. The other end of the power output shaft is connected to the generator.

[0012] Preferably, a diaphragm coupling is provided between the drive shaft and the power output shaft.

[0013] Furthermore, the low-pressure rotor pre-power extraction subsystem also includes a cooling structure, which includes a cooling exhaust pipe and a cooling air supply pipe located in the inner cavity of the load-bearing support plate, and the outer casing and the inner casing are provided with through holes through which the cooling exhaust pipe and the cooling air supply pipe pass.

[0014] Furthermore, the low-pressure rotor pre-power extraction subsystem also includes an air intake cap, which is disposed at the front end of the support structure;

[0015] The air intake cap and / or the load-bearing support plate are provided with heating elements, which are any one of metal resistance wire, metal resistance sheet, and metal resistance film.

[0016] Secondly, the present invention provides a method for extracting the front power of a high bypass ratio aero-engine, including a design step for the front power extraction method and a design step for the front power extraction system.

[0017] The design steps for the pre-power extraction method include: high-voltage rotor power extraction and low-voltage rotor power extraction allocation;

[0018] The design of the pre-power extraction system includes: designing any one or more of the power output structure, support structure, and cooling structure in the low-pressure rotor pre-power extraction subsystem.

[0019] Furthermore, the allocation of high-pressure rotor power extraction and low-pressure rotor power extraction includes: obtaining the low-pressure rotor power extraction range based on engine performance, high-pressure rotor power limit, high-pressure rotor and low-pressure rotor performance matching, and under the conditions of satisfying engine component efficiency and engine rotor component instability boundary margin.

[0020] Compared with existing technologies, the beneficial effects of this invention are as follows: The engine front-end power extraction system and method designed in this invention extract a portion of the front-end power through a low-pressure rotor, ensuring the power requirements of the aero-engine while reducing the compressor's margin. Furthermore, from a systems engineering perspective, the low-pressure rotor front-end power extraction subsystem is designed, particularly its support structure, cooling structure, and front-end power transmission structure. The front-end power extraction system designed in this invention has the following advantages:

[0021] 1. The design of the support structure solved the technical problems of low rotor speed of high bypass ratio aero-engines and large motor design that could not be built-in, as well as the aerodynamic excitation and anti-icing problems caused by conventional support structures.

[0022] 2. The front-end power transmission structure adopts a three-section design, which solves the rotor dynamics problem caused by the electromechanical conversion of aero engines;

[0023] The system and method designed in this invention have been applied in the development of a certain type of turbofan engine. It is a highly reliable power extraction technology for high bypass ratio aero-engines, filling a gap in the industry and having important guiding significance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0025] Figure 1 This is a schematic diagram of the low-pressure rotor front power extraction subsystem of the high bypass ratio aero-engine front power extraction system in a specific implementation.

[0026] The components include: 1. Fan casing; 2. Outer casing; 3. Fan rotor blades; 4. Inner casing; 5. Drive shaft; 6. Diaphragm coupling; 7. Power output shaft; 8. Support plate; 9. Cooling exhaust pipe; 10. Heating element; 11. Generator; 12. Inlet hood; 13. Heating cable; 14. Cooling air supply pipe; 15. Power transmission cable; and 16. Motor control cable. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0028] Example 1:

[0029] This embodiment provides a method for extracting the front power of a high bypass ratio aero-engine, including the design steps of the front power extraction method and the design steps of the front power extraction system.

[0030] The design steps for the pre-power extraction method include: high-voltage rotor power extraction and low-voltage rotor power extraction allocation.

[0031] In this step, the allocation of high-pressure rotor power extraction and low-pressure rotor power extraction includes: obtaining the low-pressure rotor power extraction range based on engine performance, high-pressure rotor power limit, high-pressure rotor and low-pressure rotor performance matching, and under the conditions of satisfying engine component efficiency and engine rotor component instability boundary margin.

[0032] The design of the pre-power extraction system includes: designing any one or more of the power output structure, support structure, and cooling structure in the low-pressure rotor pre-power extraction subsystem.

[0033] Optionally, since high-bypass turbofan engines have low rotational speeds and low extractable power, a larger permanent magnet or three-stage motor is selected in this embodiment to extract power.

[0034] Optionally, by comprehensively considering factors such as motor heat generation, structural design, external system layout, and the high pressure at the engine's bleed air location, this specific embodiment selects air cooling to meet the motor's cooling requirements.

[0035] Example 2:

[0036] This embodiment provides a high bypass ratio aero-engine front power extraction system. The engine front power extraction system includes a high-pressure rotor front power extraction subsystem. The high-pressure rotor front power extraction subsystem adopts an existing design method and will not be described in this embodiment.

[0037] The engine front power extraction system also includes a low-pressure rotor front power extraction subsystem, which includes a support structure and a front power transmission device.

[0038] In this specific embodiment, the generator 11 is installed using a front-support + rear-fixing method. For details, please refer to [link / reference]. Figure 1 As shown, the support structure includes a coaxial outer casing 2 and an inner casing 4. The outer casing 2 is connected to the fan casing 1, and the front end of the inner casing 4 is connected to the outer casing 2 via a load-bearing support plate 8. The rear end of the inner casing 4 overlaps with the low-pressure rotor disk, and the generator 11 is assembled in the inner cavity of the front end of the inner casing 4. The load-bearing support plate 8 is distributed circumferentially, which can reduce the vibration response of the generator 11 when the engine is running. An outer flow channel intake wall is formed between the outer casing 2 and the inner casing 4, and the outer casing 2 and the fan casing 1 are connected by bolts, which can transfer the load generated by the entire support structure to the engine power transmission system.

[0039] In this embodiment, the load-bearing support plate 8 is a hollow structure, which is used for the arrangement of cable leads such as power transmission cable 15 and motor control cable 16.

[0040] Furthermore, when the engine is running, the excitation force generated by airflow separation will affect the vibration of the fan rotor. Aerodynamic analysis results show that, under the premise of reasonable design of the shape of the load-bearing support plate 8, the setting of the axial distance between the load-bearing support plate 8 and the fan rotor blades 3 can also effectively reduce the aerodynamic excitation effect. Therefore, in this embodiment, the axial distance between the load-bearing support plate 8 and the fan rotor blades 3 is 1 to 2 times the chord length of the fan rotor blades 3, and the optimal axial distance between the load-bearing support plate 8 and the fan rotor blades 3 is 1.5 to 2 times.

[0041] Further, see Figure 1 As shown, the front power transmission device is located in the rear end cavity of the inner casing 4, and one end of the front power transmission device is connected to the generator 11, and the other end is connected to the low-pressure rotor disk.

[0042] Furthermore, see Figure 1 As shown, the front-end power transmission device is located between the low-pressure rotor and the generator 11, and includes a drive shaft 5 connected in sequence. The other end of the drive shaft 5 is disposed on the low-pressure rotor blade disk, and the other end is connected to the power output shaft 7. The other end of the power output shaft 7 is connected to the generator 11.

[0043] Preferred, see Figure 1 As shown, a diaphragm coupling 6 is provided between the drive shaft 5 and the power output shaft 7. When the pre-power is extracted, the diaphragm coupling 6 can generate flexible deformation to compensate for the problems of low-pressure rotor eccentricity and unstable operation of the pre-power transmission device.

[0044] Furthermore, the low-pressure rotor pre-power extraction subsystem also includes a cooling structure, see [link to relevant documentation]. Figure 1 As shown, the cooling structure includes a cooling exhaust pipe 9 and a cooling air supply pipe 14 located in the inner cavity of the load-bearing support plate 8, and the outer casing 2 and the inner casing 4 are provided with through holes through which the cooling exhaust pipe 9 and the cooling air supply pipe 14 pass.

[0045] Further, see Figure 1 As shown, the low-pressure rotor front power extraction subsystem also includes an air intake cap 12, which is disposed at the front end of the support structure.

[0046] Furthermore, see Figure 1 As shown, the air intake cap 12 and / or the load-bearing support plate 8 are equipped with heating elements 10. When the aircraft engine needs anti-icing, the heating elements 10 can be heated and anti-iced by the generator powered by the generator through a control signal transmitted by the engine. In this specific embodiment, the heating element 10 can be any one of metal resistance wire, metal resistance sheet, or metal resistance film. The heating element 10 is connected to the generator 11 via a heating cable 13.

[0047] The engine front-end power extraction system and method designed in this invention extract a portion of the front-end power through a low-pressure rotor, ensuring the power requirements of the aero-engine while reducing the compressor's margin. Furthermore, from a systems engineering perspective, the low-pressure rotor front-end power extraction subsystem is designed, particularly its support structure, cooling structure, and front-end power transmission structure. The front-end power extraction system designed in this invention has the following advantages:

[0048] 1. The design of the support structure solved the technical problems of low rotor speed of high bypass ratio aero-engines and large motor design that could not be built-in, as well as the aerodynamic excitation and anti-icing problems caused by conventional support structures.

[0049] 2. The front-end power transmission structure adopts a three-section design, which solves the rotor dynamics problem caused by the electromechanical conversion of aero engines;

[0050] The system and method designed in this invention have been applied in the development of a certain type of turbofan engine. It is a highly reliable power extraction technology for high bypass ratio aero-engines, filling a gap in the industry and having important guiding significance.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high bypass ratio aero-engine front-end power extraction system, characterized in that, It includes a low-voltage rotor front-end power extraction subsystem, which includes a support structure and a front-end power transmission device; The support structure includes a coaxial outer casing (2) and an inner casing (4). The outer casing (2) is connected to the fan casing (1). The front end of the inner casing (4) is connected to the outer casing (2) via a load-bearing support plate (8). The rear end of the inner casing (4) overlaps with the low-pressure rotor blade disk. A generator (11) is installed in the inner cavity of the front end of the inner casing (4). The generator (11) is a permanent magnet motor or a three-stage motor. The load-bearing support plate (8) is a hollow structure used to arrange power transmission cables and motor control cables. The axial distance between the load-bearing support plate (8) and the fan rotor blades (3) is 1 to 2 times the chord length of the fan rotor blades (3). The front power transmission device is located in the rear end cavity of the inner casing (4) and is set between the low-pressure rotor and the generator. It includes a drive shaft (5) and a power output shaft (7) connected in sequence. One end of the drive shaft (5) is set on the low-pressure rotor blade disk, and the other end is connected to the power output shaft (7). The other end of the power output shaft (7) is connected to the generator. A diaphragm coupling (6) is provided between the drive shaft (5) and the power output shaft (7).

2. The high bypass ratio aero-engine front power extraction system according to claim 1, characterized in that: The low-pressure rotor pre-power extraction subsystem also includes a cooling structure, which includes a cooling exhaust pipe (9) and a cooling air supply pipe (14) located in the inner cavity of the load-bearing support plate (8), and the outer casing (2) and the inner casing (4) are provided with through holes through which the cooling exhaust pipe (9) and the cooling air supply pipe (14) pass.

3. The high bypass ratio aero-engine front power extraction system according to claim 1, characterized in that: The low-pressure rotor pre-power extraction subsystem also includes an air intake hood (12), which is disposed at the front end of the support structure; Heating elements (10) are provided on the air intake cap (12) and / or the load-bearing support plate (8).

Images