CN116044604A

CN116044604A - Variable cycle engine and aircraft

Info

Publication number: CN116044604A
Application number: CN202310041767.8A
Authority: CN
Inventors: 罗斌; 张亚华; 陈前景; 贾志刚; 邵冬; 刘金超; 董芃呈; 王士奇
Original assignee: China Aero Engine Research Institute
Current assignee: China Aero Engine Research Institute
Priority date: 2023-01-12
Filing date: 2023-01-12
Publication date: 2023-05-02

Abstract

The invention provides a variable cycle engine and an aircraft, relates to the technical field of engines, and solves the problem that the variable cycle engine cannot effectively improve the wide-range matching performance of an engine body and the wide-range adaptability of the variable cycle engine to tasks. The variable cycle engine comprises a first compressor, a second compressor, a high-pressure turbine, a low-pressure turbine and an air pushing device for providing air for the first compressor or the second compressor; the low-pressure turbine is in transmission connection with the air pushing device through a first shaft; the engine is provided with a first outer duct at one side of the first air compressor, and a second outer duct at one side of the second air compressor, wherein the flow area of the first outer duct is larger than that of the second outer duct; the diameter of the first air compressor is smaller than that of the second air compressor, and the pressure ratio of the first air compressor is larger than that of the second air compressor; when the engine is in a large bypass ratio mode, the high-pressure turbine is in transmission connection with the first air compressor through the second shaft, and the high-pressure turbine is in transmission disconnection with the second air compressor.

Description

Variable cycle engine and aircraft

Technical Field

The invention relates to the field of engines, in particular to a variable cycle engine and an aircraft.

Background

For a typical aircraft, subsonic flight uses a relatively large bypass engine and supersonic flight uses a relatively small bypass engine to achieve optimal matching performance. However, for aircraft that require both subsonic and supersonic flight capabilities, the performance cannot be improved using a fixed bypass ratio engine.

The existing variable cycle engine scheme changes the duct ratio by adjusting the circulation capacity of the outer duct, has extremely high requirements on the stable working range of the inner duct compressor, and causes difficult performance matching of the whole machine; meanwhile, the direction of the change of the bypass ratio is opposite to the direction of the change of the supercharging ratio, so that the bypass ratio and the supercharging ratio cannot be optimally matched in a wide range, and the adaptability of the whole machine to tasks is low.

Disclosure of Invention

In order to solve the technical problems, the invention provides a variable cycle engine and an aircraft.

The present invention has been made to overcome the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a variable cycle engine, which includes a first compressor, a second compressor, a high pressure turbine, a low pressure turbine, and an air pushing device for providing air to the first compressor or the second compressor;

the low-pressure turbine is in transmission connection with the air pushing device through a first shaft;

the engine is provided with a first outer duct at one side of the first air compressor, the engine is provided with a second outer duct at one side of the second air compressor, and the flow area of the first outer duct is larger than that of the second outer duct;

the diameter of the first air compressor is smaller than that of the second air compressor, and the pressure ratio of the first air compressor is larger than that of the second air compressor;

when the engine is in a large bypass ratio mode, the high-pressure turbine is in transmission connection with the first compressor through a second shaft, and the high-pressure turbine is disconnected from the second compressor;

when the engine is in a low bypass ratio mode, the high-pressure turbine is in transmission connection with the second compressor through a second shaft, and the high-pressure turbine is in transmission disconnection with the first compressor.

According to at least one embodiment of the invention, the engine further comprises first on-off means for controlling air to enter the first compressor and the first outer duct, and second on-off means for controlling air to enter the second compressor and the second outer duct;

when the engine is in a large bypass ratio mode, the first switching device is opened, and the second switching device is closed;

when the engine is in a low bypass ratio mode, the second switching device is opened, and the first switching device is closed.

According to at least one embodiment of the invention, the first on-off device comprises a first guide vane ring coordinated with the inlet end of the first compressor and a first valve arranged at the end part of the first outer duct close to the tail nozzle;

the second switching device comprises a second guide vane ring coordinated with the inlet end of the second compressor and a second valve arranged at the end part of the second outer duct close to the tail nozzle.

According to at least one embodiment of the present invention, the air pushing device comprises two fans, each of which is coordinated with the corresponding first compressor or second compressor, and the tail ends of the two fans are communicated;

the tail end of each fan is an end close to the inlet end of the corresponding first compressor or the inlet end of the corresponding second compressor;

the low-pressure turbine is in driving connection with the two fans through a first shaft respectively.

According to at least one embodiment of the invention, the engine further comprises a first differential arranged at the end of the second shaft facing away from the high-pressure turbine, the first differential being in driving connection with the first compressor and the second compressor respectively through corresponding first driving shafts;

each first transmission shaft is provided with a brake, and each brake is used for controlling the corresponding first air compressor or second air compressor to stop rotating.

According to at least one embodiment of the invention, the engine further comprises a second differential arranged at the end of the first shaft facing away from the low-pressure turbine, said second differential being in driving connection with the two fans respectively via respective second transmission shafts.

According to at least one embodiment of the invention, the second shaft is a tubular shaft, and the second shaft is sleeved outside the first shaft.

According to at least one embodiment of the present invention, the first vane ring includes a plurality of first vanes circumferentially distributed along the inlet end of the first compressor, and a plurality of first shafts provided on the first compressor, each of the first vanes being movably connected to a corresponding one of the shafts;

when the engine is in a low bypass ratio mode, each first guide vane is used for blocking the inlet end of the first compressor; and/or the number of the groups of groups,

the second guide vane ring comprises a plurality of second guide vanes distributed along the circumferential direction of the inlet end of the second compressor and a plurality of second rotating shafts arranged on the second compressor, and each second guide vane is movably connected with the corresponding second rotating shaft;

and when the engine is in a large bypass ratio mode, each second guide vane is used for blocking the inlet end of the second compressor.

According to at least one embodiment of the present invention, the engine further comprises a controller for controlling the second compressor to stop rotating when the engine is in a large bypass ratio mode, the second vane ring and the second valve being closed;

when the engine is in a low bypass ratio mode, the controller is used for controlling the first compressor to stop rotating, and the first guide vane ring and the first valve are closed.

Compared with the prior art, the variable cycle engine has the following advantages:

the variable cycle engine provided by the embodiment of the invention comprises a first compressor, a second compressor, a high-pressure turbine, a low-pressure turbine and an air pushing device for providing air for the first compressor or the second compressor, wherein the flow area of a first outer duct on one side of the first compressor is larger than that of a second outer duct, the diameter of the first compressor is smaller than that of the second compressor, and the pressure ratio of the first compressor is larger than that of the second compressor, so that the first compressor forms a high-pressure ratio low-flow compressor, and the second compressor forms a low-pressure ratio high-flow compressor; the high-pressure turbine is driven or disconnected from the first air compressor and the second air compressor through the second shaft, so that the two air compressors can be switched, when the high-pressure turbine is switched to the first air compressor with high pressure ratio and low flow, the bypass ratio and the total pressure ratio of the engine are both large, and the low-speed low-oil consumption subsonic cruise is realized; when the low-pressure ratio high-flow second compressor is switched, the bypass ratio and the total pressure ratio of the engine are smaller, the engine has the advantage of high Ma thrust and is suitable for high Ma flight, and therefore power is provided for the multi-task flight of the aircraft. By introducing two compressors, the variation range of the bypass ratio of the engine can be greatly improved, so that the wide-range matching performance of the engine body and the wide-range adaptability to tasks are improved.

Another object of the invention is also an aircraft comprising a variable cycle engine as described above.

The advantages of the aircraft over the prior art are the same as those of the variable cycle engine described above over the prior art and are not described in detail here.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a schematic diagram of a structure in a variable cycle engine large bypass ratio mode according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a variable cycle engine in a small bypass ratio mode according to an embodiment of the present invention.

Fig. 3 is a schematic structural view of a guide vane ring according to an embodiment of the present invention, wherein a is an open state and b is a closed state.

Fig. 4 is a schematic structural view of a brake according to an embodiment of the present invention, wherein a is an unbraked state and b is a braked state.

Reference numerals: 10. a first compressor; 11. a first outer duct; 12. a first guide vane ring; 121. a first guide vane; 122. a first rotating shaft; 13. a first valve; 20. a second compressor; 21. a second outer duct; 22. a second guide vane ring; 23. a second valve; 30. a low pressure turbine; 31. a first shaft; 40. a high pressure turbine; 41. a second shaft; 50. a fan; 61. a first differential; 62. a first drive shaft; 63. a brake; 71. a second differential; 72. a second drive shaft; 80. a combustion chamber; 90. a tail pipe.

Detailed Description

The present invention will be described in further detail with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the substances, and not restrictive of the invention. It should be further noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

In addition, the embodiments of the present invention and the features of the embodiments may be combined with each other without collision. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The performance of jet aero gas turbine engines is closely related to the cycle parameters of bypass ratio, boost ratio, etc. In order to ensure that the whole machine has better matching performance and wider task adaptability, the larger the bypass ratio is, the larger the supercharging ratio is, so that the whole machine is suitable for low-speed flight, and the smaller the bypass ratio is, the smaller the supercharging ratio is, so that the whole machine is suitable for high-speed flight.

For fighter, subsonic and supersonic flight capabilities are required to be simultaneously considered, if an engine with a fixed duct ratio is used, the fighter performance is limited, for example, subsonic and supersonic cruising oil consumption is higher, the limit height and the flight speed are limited, and the performance of the fighter plane can be greatly improved by developing a variable-circulation aeroengine with a variable duct ratio.

The existing variable cycle engine scheme cannot effectively improve the wide-range matching performance of the engine body and the wide-range adaptability of the engine body to tasks.

Referring to fig. 1-2, an embodiment of the present invention provides a variable cycle engine, which includes a first compressor 10, a second compressor 20, a high pressure turbine 40, a low pressure turbine 30, and an air pushing device for providing air to the first compressor 10 or the second compressor 20; the low-pressure turbine 30 is in driving connection with the air pushing device through a first shaft 31; the engine is provided with a first outer duct 11 on the side of the first compressor 10, and is provided with a second outer duct 21 on the side of the second compressor 20, wherein the flow area of the first outer duct 11 is larger than that of the second outer duct 21; the diameter of the first compressor 10 is smaller than the diameter of the second compressor 20, and the pressure ratio of the first compressor 10 is larger than the pressure ratio of the second compressor 20; when the engine is in a large bypass ratio mode, the high-pressure turbine 40 is in transmission connection with the first compressor 10 through the second shaft 41, and the high-pressure turbine 40 is in transmission disconnection with the second compressor 20; when the engine is in the low bypass mode, the high pressure turbine 40 is drivingly connected to the second compressor 20 by the second shaft 41, and the high pressure turbine 40 is drivingly disconnected from the first compressor 10.

Because the diameter of the first compressor 10 is small and the flow area of the corresponding first outer duct 11 is larger than that of the second outer duct 21, the pressure ratio of the first compressor 10 is also larger than that of the second compressor 20, and therefore, when the first compressor 10 works alone, the engine is in a large-duct ratio mode, namely, the duct ratio is large, the flow is small, and the supercharging ratio is large; accordingly, when the second compressor 20 is operated alone, the engine is in a small bypass ratio mode, i.e., the bypass ratio is small, the flow rate is large, and the supercharging ratio is small. The high-pressure turbine 40 is in transmission connection or disconnection with the first air compressor 10 through the second shaft 41 and in transmission connection or disconnection with the second air compressor 20, and can be switched between the first air compressor 10 and the second air compressor 20, so that the engine can play a good role in subsonic and supersonic flight, and the wide-range matching performance and the wide-range adaptability to tasks of the engine body are greatly improved.

In actual use, the low-pressure turbine drives the air pushing device to provide air for the air compressor through the first shaft 31, when the engine is in a large bypass ratio mode, please refer to fig. 1, wherein a dashed arrow shows a flow path of the air in the engine, the high-pressure turbine 40 drives the first air compressor 10 to rotate to do work through the second shaft 41, at this time, the high-pressure turbine 40 is disconnected from the second air compressor 20, the second air compressor 20 does not work, the air from the air pushing device enters the first air compressor 10 and the corresponding first outer bypass 11, and the air entering the first air compressor 10 is discharged through the combustion chamber 80, the high-pressure turbine 40, the low-pressure turbine 30 and the tail nozzle 90; the air entering the first outer duct 11 is discharged through the tail nozzle 90, and in the mode, the duct ratio and the total pressure ratio are large, so that the air has the characteristics of low subsonic oil consumption, high thrust and the like, and is suitable for being used in subsonic flight.

Referring to fig. 2, wherein the dashed arrow shows the flow path of air in the engine, the high-pressure turbine 40 drives the second compressor 20 to rotate through the second shaft 41 to apply work, at this time, the high-pressure turbine 40 is disconnected from the first compressor 10, the first compressor 10 is not operated, the air from the air pushing device enters the second compressor 20 and the corresponding second outer duct 21, wherein the air entering the second compressor 20 is discharged through the combustion chamber 80, the high-pressure turbine 40, the low-pressure turbine 30 and the tail nozzle 90; the air entering the second outer duct 21 is discharged through the tail nozzle 90, and in the mode, the duct ratio and the total pressure ratio of the engine are smaller, so that the engine has the characteristics of large limit flight Ma, large supersonic thrust, low fuel consumption and the like, and is suitable for being used in supersonic flight.

It will be appreciated that in order to obtain a high pressure ratio of the first compressor 10, the greater the number of stages of the first compressor 10, the greater the length, the greater the pressure ratio that can be obtained, illustratively, the number of stages of the first compressor 10 in fig. 1 is 5. Whereas, in order to obtain a small pressure ratio of the second compressor 20, the smaller the number of stages of the second compressor 20, the shorter the length, the smaller the pressure ratio that can be obtained, the second compressor 20 in fig. 1 is exemplified as having a number of stages of 3. Therefore, the wide-range matching performance and the wide-range adaptability of the task of the variable cycle engine are improved, and the engine can play a good role in subsonic and supersonic flight.

To achieve efficient air utilization, in some embodiments, the engine further comprises first on-off means for controlling the air to enter the first compressor 10 and the first outer duct 11, and second on-off means for controlling the air to enter the second compressor 20 and the second outer duct 21; when the engine is in a large bypass ratio mode, the first switching device is opened, and the second switching device is closed; i.e. blocking the air flow through the second compressor 20 and the second outer duct 21, so that all air from the air pushing device enters the first compressor 10 and the first outer duct 11.

When the engine is in the low bypass ratio mode, the second on-off device is opened and the first on-off device is closed, i.e. the air flow from the first compressor 10 and the first outer bypass 11 is blocked, so that all air from the air pushing device enters the second compressor 20 and the second outer bypass 21.

The specific forms of the first switching device and the second switching device are various, so long as blocking of air circulation can be achieved.

For example, the first on-off device comprises a first guide vane ring 12 coordinated with the inlet end of the first compressor 10, and a first valve 13 arranged at the end of the first outer duct 11 close to the tail nozzle; when the first guide vane ring 12 is closed, the annular inlet at the inlet end of the first compressor 10 is completely covered, so as to prevent air from entering the first compressor, and a first valve 13 is disposed at the end of the first outer duct 11 close to the tail nozzle, that is, at a position with a smaller size, an injection valve is used for example, when the first valve is opened, the direction of injecting gas and the injection direction of the first outer duct 11 tend to be consistent, and please refer to the injection state when the first valve 13 is opened in fig. 1.

The second switching device is similar to the first switching device in structure, and illustratively, the second switching device includes a second guide vane ring 22 coordinated with the inlet end of the second compressor 20, and a second valve 23 disposed at the end of the second outer duct 21 near the tail nozzle. When the second guide vane ring 22 is closed, the annular inlet at the inlet end of the second compressor 20 is completely covered, so as to prevent air from entering the second compressor 20, and a second valve 23 is disposed at the end of the second outer duct 21 close to the tail nozzle, that is, at a position with a smaller size, and an injection valve is used for example, when the second guide vane ring is opened, the direction of injecting gas and the injection direction of the second outer duct 21 tend to be consistent, and please refer to the injection state of the second valve 23 when opened in fig. 2.

Illustratively, the first vane ring 12 and the second vane ring 22 have similar structural forms, and the first vane ring 12 includes a plurality of first vanes 121 circumferentially distributed along the inlet end of the first compressor 10, and a plurality of first shafts 122 provided on the first compressor 10, where each first vane is movably connected to a corresponding shaft; when the engine is in a low bypass ratio mode, each first guide vane is used for blocking the inlet end of the first compressor 10; the second vane ring 22 includes a plurality of second vanes circumferentially distributed along the inlet end of the second compressor 20, and a plurality of second rotating shafts provided on the second compressor 20, each second vane being movably connected to a corresponding second rotating shaft; each second vane is used to block the inlet end of the second compressor 20 when the engine is in the large bypass ratio mode.

The embodiment of the present invention is illustrated by taking the structural form of the first guide vane ring 12 as an example, please refer to fig. 3, wherein a is an open state of the first guide vane ring 12, and b is a closed state of the first guide vane ring 12. A plurality of first rotating shafts 122 are arranged at intervals along the circumferential direction in the annular inlet of the inlet end of the first compressor 10, and each first rotating shaft 122 is movably connected with a first guide vane 121, when the first guide vane ring 12 is closed, the first guide vanes 121 rotate around the corresponding first rotating shaft 122 to a position perpendicular to the incoming flow direction, and each first guide vane 121 forms a channel covering the annular inlet of the first compressor 10 so as to block air from entering the first compressor 10; when the first vane ring 12 needs to be opened, the first vanes 121 rotate around the corresponding first rotating shafts 122 to a position parallel to the incoming flow direction, so that air can smoothly enter the first compressor 10, and the air amount entering the first compressor 10 is prevented from being influenced as much as possible. It will be appreciated that the first vane ring 12 described above may also be in the form of a camera shutter-like structure that blocks air.

Illustratively, the structural form and the working principle of the second guide vane ring 22 according to the embodiment of the present invention are the same as those of the first guide vane ring 12, and will not be described herein.

In some embodiments, the air pushing device in the variable cycle engine according to the embodiment of the present invention includes two fans 50, it is understood that the number of fans is not limited to two, but may be one fan, where the main shaft of the fan is in driving connection with the low pressure turbine 30 through the first shaft 31, so that the corresponding transmission shaft is omitted, and the first shaft 31 is connected with the main shaft of the fan through the coupling, so that the transmission efficiency is higher, and the structure is relatively simple. The number of the fans can be more than two, so that the air flow entering the air compressor can be conveniently regulated and controlled. The embodiment of the present invention is illustrated with two fans 50, where each fan 50 of the two fans is aligned with the corresponding first compressor 10 or second compressor 20, i.e., the central axis of each fan 50 is generally on an axis or parallel to and spaced apart from the central axis of the corresponding first compressor 10 or second compressor 20 by a small distance. The tail ends of the two fans 50 are communicated; the aft end of each fan 50 is the end that is proximate to the inlet end of the corresponding first compressor 10 or the inlet end of the second compressor 20; the low-pressure turbine 30 is in driving connection with two fans 50 via a first shaft 31, respectively. The first air compressor 10 corresponds to one fan 50, the second air compressor 20 corresponds to the other fan 50, a passage is arranged at the middle position in front of the two air compressors, so that the air of one fan 50 can be mixed into the air provided by the other fan 50 through the passage, and the mixed air enters the corresponding first air compressor 10 and the corresponding first outer duct 11 or enters the second air compressor 20 and the corresponding second outer duct 21. Such a design of two fans 50 in parallel may allow for a significant increase in the intake efficiency of each compressor.

Considering that the first compressor 10 and the second compressor 20 are generally used independently, the rotation speeds of the two are different, and the variable cycle engine further comprises a first differential 61 disposed at the end of the second shaft 41 facing away from the high-pressure turbine 40, and the first differential 61 is in driving connection with the first compressor 10 and the second compressor 20 through corresponding first transmission shafts 62, respectively; each first transmission shaft 62 is provided with a brake 63, and each brake 63 is used for controlling the corresponding first compressor 10 or second compressor 20 to stop rotating. The use of the first differential 61 can make one of the compressors rotate to apply work and the other compressor completely stop, and in order to control the stopped compressor, a brake 63 is arranged on the first differential 61 and the first transmission shaft 62 of the corresponding compressor or on the main shaft of the corresponding compressor, and the rotation or stop of the corresponding compressor is controlled by opening and closing the brake 63.

Since the transmission devices and the braking devices of the two compressors are similar, the embodiment of the invention is described by taking the transmission device and the braking device of the first compressor as an example, as shown in fig. 4, one end of the first transmission shaft 62 is connected with the first differential 61, the other end is connected with the main shaft of the first compressor 10 through a pair of bevel gear pairs, wherein the brake 63 is arranged on the first transmission shaft 62, when the engine is in the large bypass ratio mode, the brake 63 is in an open state (fig. 4 a), the first compressor 10 rotates to apply work at this moment, and when the engine is in the small bypass ratio mode, the brake 63 is in a braking state (fig. 4 b), at this moment, the first compressor 10 stops rotating to apply work, the brake 63 on the first transmission shaft 62 in transmission connection with the second compressor 20 is in an open state, and the second compressor 20 rotates to apply work.

In some embodiments, the variable cycle engine further comprises a second differential 71 provided at the end of the first shaft 31 facing away from the low pressure turbine 30, the second differential 71 being in driving connection with the two fans 50, respectively, by means of a respective second transmission shaft 72. Illustratively, the second drive shaft 72 is coupled to the rotational shafts of the fans 50 in the form of a pair of bevel gear pairs, it being understood that under normal symmetrical intake conditions, both fans 50 are at equal rotational speeds in any mode, and the purpose of the second differential 71 is to account for possible asymmetry in the intake conditions of both fans 50, thereby increasing the stable operating range of both fans 50.

In some embodiments, as shown in fig. 1-2, the second shaft 41 is a tubular shaft, the second shaft 41 is sleeved outside the first shaft 31, in order to transmit the power of the low-pressure turbine 30 to the fan 50, and transmit the power of the high-pressure turbine 40 to the first compressor 10 or the second compressor 20, the second shaft 41 is sleeved on the first shaft 31 in a manner of an driving sleeve, that is, the second shaft 41 has a hollow tube structure, and both ends of the first shaft 31 extend out of the second shaft 41 to be in driving connection with the fan and the low-pressure turbine 30 respectively. The arrangement mode of the transmission shaft avoids a complex transmission system, is simple and efficient, does not occupy excessive engine space, reduces dead weight of the engine by adopting the tubular shaft, and is very important for an aeroengine.

Illustratively, the variable cycle engine further comprises a controller, wherein when the engine is in the high bypass ratio mode, the controller is configured to control the second compressor 20 to stop rotating, and the second vane ring 22 and the second valve 23 are closed; specifically, the controller is in communication connection with the corresponding brake 63 of the second compressor 20, and is also in communication connection with the second guide vane ring 22 and the second valve 23, and when the system receives that the large bypass ratio mode is required, the controller respectively controls the corresponding brake 63 to brake and controls the second guide vane ring 22 and the second valve 23 to close, so that air completely flows to the first compressor 10 and the corresponding first outer bypass 11, and the first compressor 10 rotates to apply work.

When the engine is in the low bypass ratio mode, the controller is used for controlling the first compressor 10 to stop rotating, and the first guide vane ring 12 and the first valve 13 are closed. Specifically, the controller is in communication connection with the corresponding brake 63 of the first compressor 10, and is also in communication connection with the first vane ring 12 and the first valve 13, and when the system receives that the small bypass ratio mode is required, the controller respectively controls the corresponding brake 63 to brake and controls the first vane ring 12 and the first valve 13 to be closed, so that air completely flows to the second compressor 20 and the corresponding second outer bypass 21, and the second compressor 20 rotates to apply work.

In addition, the above components are key components of the main body of the variable cycle engine, and other components such as a shell, a bearing, an oil seal, a combustion chamber, a tail nozzle and the like are not listed one by one, and the functions are the inherent functions of the components.

The embodiment of the invention also provides an aircraft, which comprises the variable cycle engine, and the implementation of the specific functions of the aircraft provided by the embodiment is described with reference to the variable cycle engine, and is not repeated here.

It should be noted that the variable cycle engine of the present invention may be applied to other vehicles requiring power, such as gas turbines, automobiles, ships, airships, etc.

In the description of the present specification, reference to the terms "one embodiment/manner," "some embodiments/manner," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/manner or example is included in at least one embodiment/manner or example of the present application. In this specification, the schematic representations of the above terms are not necessarily for the same embodiment/manner or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/modes or examples described in this specification and the features of the various embodiments/modes or examples can be combined and combined by persons skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless explicitly defined otherwise.

It will be appreciated by persons skilled in the art that the above embodiments are provided for clarity of illustration only and are not intended to limit the scope of the invention. Other variations or modifications will be apparent to persons skilled in the art from the foregoing disclosure, and such variations or modifications are intended to be within the scope of the present invention.

Claims

1. A variable cycle engine comprising a first compressor, a second compressor, a high pressure turbine, a low pressure turbine, and an air pushing device for providing air to either the first compressor or the second compressor;

2. The variable cycle engine of claim 1, further comprising first on-off means for controlling air to the first compressor and the first outer duct, and second on-off means for controlling air to the second compressor and the second outer duct;

3. The variable cycle engine of claim 2, wherein the first on-off device comprises a first vane ring coordinated with the first compressor inlet end, and a first valve disposed at an end of the first outer duct near the tail jet;

4. A variable cycle engine according to any one of claims 1-3, wherein said air pushing device comprises two fans, each of said fans being coordinated with a respective one of said first compressor or said second compressor, the aft ends of both of said fans being in communication;

5. A variable cycle engine as defined in claim 3, further comprising a first differential disposed at an end of the second shaft facing away from the high pressure turbine, the first differential being drivingly connected to the first and second compressors, respectively, by respective first drive shafts;

6. The variable cycle engine of claim 4, further comprising a second differential disposed at an end of the first shaft facing away from the low pressure turbine, the second differential being drivingly connected to the two fans via respective second drive shafts.

7. The variable cycle engine of claim 4, wherein the second shaft is a tubular shaft, the second sleeve being disposed outside the first shaft.

8. The variable cycle engine of claim 3, wherein the first vane ring comprises a plurality of first vanes circumferentially distributed along the first compressor inlet end, and a plurality of first shafts provided on the first compressor, each first vane being movably connected to a respective one of the shafts;

9. The variable cycle engine of claim 5, further comprising a controller for controlling the second compressor to stop rotating when the engine is in a large bypass ratio mode, the second vane ring and the second valve being closed;

10. An aircraft, characterized in that it comprises a variable cycle engine according to any one of claims 1-9.