A variable cycle engine, an aircraft

Abstract

The present invention provides a variable cycle engine and an aircraft, relating to the technical field of engines, and solving the problem that a variable cycle engine cannot effectively improve the wide-range matching of the engine body and its wide-range adaptability to missions. The variable cycle engine includes a first compressor, a second compressor, a high-pressure turbine, a low-pressure turbine, and an air pushing device for supplying air to the first compressor or the second compressor; the low-pressure turbine is drivingly connected to the air pushing device through a first shaft; the engine has a first bypass duct on one side of the first compressor and a second bypass duct on one side of the second compressor, and the flow area of the first bypass duct is larger than that of the second bypass duct; the diameter of the first compressor is smaller than that of the second compressor, and the pressure ratio of the first compressor is greater than that of the second compressor; when the engine is in the high-bypass ratio mode, the high-pressure turbine is drivingly connected to the first compressor through a second shaft, and the driving connection between the high-pressure turbine and the second compressor is disconnected.

Description

Technical Field

[0001] The present invention relates to the field of engines, and in particular to a variable cycle engine and an aircraft. Background Art

[0002] For general aircraft, engines with a relatively large bypass ratio are used for subsonic flight, and engines with a relatively small bypass ratio are used for supersonic flight to achieve the best matching performance. However, for aircraft that need to balance subsonic and supersonic flight capabilities, using an engine with a fixed bypass ratio cannot improve its performance.

[0003] Existing variable cycle engine solutions change the bypass ratio by adjusting the flow capacity of the outer bypass duct, which has extremely high requirements for the stable operating range of the inner bypass compressor, resulting in difficult matching of the overall engine performance; at the same time, since the direction of change in the bypass ratio is opposite to the direction of change in the pressure ratio, the bypass ratio and the pressure ratio cannot achieve an optimal match over a wide range, thus reducing the adaptability of the overall engine to missions. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a variable cycle engine and an aircraft.

[0005] The purpose of the present invention is to overcome the above problems existing in the prior art and provide 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 supplying air to the first compressor or the second compressor;

[0006] The low-pressure turbine is drivingly connected to the air pushing device through a first shaft;

[0007] The engine has a first outer bypass duct on one side of the first compressor and a second outer bypass duct on one side of the second compressor, and the flow area of the first outer bypass duct is larger than that of the second outer bypass duct;

[0008] The diameter of the first compressor is smaller than that of the second compressor, and the pressure ratio of the first compressor is greater than that of the second compressor;

[0009] When the engine is in the large bypass ratio mode, the high-pressure turbine is drivingly connected to the first compressor through a second shaft, and the high-pressure turbine is disconnected from the second compressor;

[0010] When the engine is in the small bypass ratio mode, the high-pressure turbine is drivingly connected to the second compressor through a second shaft, and the high-pressure turbine is disconnected from the first compressor.

[0011] According to at least one embodiment of the present invention, the engine further includes a first on-off device for controlling air entering the first compressor and the first bypass duct, and a second on-off device for controlling air entering the second compressor and the second bypass duct;

[0012] When the engine is in a high bypass ratio mode, the first on-off device is opened and the second on-off device is closed;

[0013] When the engine is in a low bypass ratio mode, the second on-off device is opened and the first on-off device is closed.

[0014] According to at least one embodiment of the present invention, the first on-off device includes a first guide vane ring coordinated with the inlet end of the first compressor, and a first valve provided at the end of the first bypass duct near the tail nozzle;

[0015] The second on-off device includes a second guide vane ring coordinated with the inlet end of the second compressor, and a second valve provided at the end of the second bypass duct near the tail nozzle.

[0016] According to at least one embodiment of the present invention, the air pushing device includes two fans, each fan being coordinated with the corresponding first compressor or the second compressor, and the tails of the two fans being connected;

[0017] The tail of each fan is the end near the inlet end of the corresponding first compressor or the second compressor;

[0018] The low-pressure turbine is respectively drivingly connected to the two fans through a first shaft.

[0019] According to at least one embodiment of the present invention, the engine further includes a first differential provided at the end of the second shaft away from the high-pressure turbine, and the first differential is respectively drivingly connected to the first compressor and the second compressor through corresponding first transmission shafts;

[0020] A brake is provided on each of the first transmission shafts, and each brake is used to control the corresponding first compressor or the second compressor to stop rotating.

[0021] According to at least one embodiment of the present invention, the engine further includes a second differential provided at the end of the first shaft away from the low-pressure turbine, and the second differential is respectively drivingly connected to the two fans through corresponding second transmission shafts.

[0022] According to at least one embodiment of the present invention, the second shaft is a tubular shaft, and the second shaft is sleeved outside the first shaft.

[0023] According to at least one embodiment of the present invention, the first guide vane ring includes a plurality of first guide vanes circumferentially distributed along the inlet end of the first compressor, and a plurality of first rotating shafts provided on the first compressor, and each of the first guide vanes is movably connected to the corresponding rotating shaft;

[0024] When the engine is in the small bypass ratio mode, each of the first guide vanes is used to block the inlet end of the first compressor; and / or,

[0025] The second guide vane ring includes a plurality of second guide vanes circumferentially distributed along the inlet end of the second compressor, and a plurality of second rotating shafts provided on the second compressor, and each of the second guide vanes is movably connected to the corresponding second rotating shaft;

[0026] When the engine is in the large bypass ratio mode, each of the second guide vanes is used to block the inlet end of the second compressor.

[0027] According to at least one embodiment of the present invention, the engine further includes a controller. When the engine is in the large bypass ratio mode, the controller is used to control the second compressor to stop rotating, and the second guide vane ring and the second valve are closed;

[0028] When the engine is in the small bypass ratio mode, the controller is used to control the first compressor to stop rotating, and the first guide vane ring and the first valve are closed.

[0029] Compared with the prior art, the variable cycle engine of the present invention has the following advantages:

[0030] The variable cycle engine provided by the embodiment of the present invention includes a first compressor, a second compressor, a high-pressure turbine, a low-pressure turbine, and an air pushing device for supplying air to the first compressor or the second compressor. The flow area of the first outer bypass duct on one side of the first compressor is larger than that of the second outer bypass duct, the diameter of the first compressor is smaller than that of the second compressor, and the pressure ratio of the first compressor is greater than that of the second compressor. Thus, the first compressor forms a compressor with a high pressure ratio and a small flow rate, while the second compressor forms a compressor with a low pressure ratio and a large flow rate; the high-pressure turbine is transmitted or disconnected between the first compressor and the second compressor through the second shaft, so that switching can be performed between the two compressors. When switching to the first compressor with a high pressure ratio and a small flow rate, the bypass ratio and the total pressure ratio of the engine are both large, and it has the advantage of low subsonic fuel consumption and is suitable for subsonic cruise; when switching to the second compressor with a low pressure ratio and a large flow rate, the bypass ratio and the total pressure ratio of the engine are both small, and it has the advantage of high thrust at high Ma and is suitable for high Ma flight, thereby providing power for the multi-mission flight of the aircraft. By introducing two compressors, the change range of the bypass ratio of the engine can be greatly increased, thereby improving the wide-range matching of the engine body and the wide-range adaptability to missions.

[0031] Another object of the present invention is to further provide an aircraft, including the variable cycle engine described above.

[0032] The advantages of the aircraft relative to the prior art are the same as those of the variable cycle engine relative to the prior art, and will not be elaborated herein. Description of the Drawings

[0033] The drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are included in this specification and form a part of this specification.

[0034] Figure 1 It is a schematic structural view of the variable cycle engine in the high bypass ratio mode according to an embodiment of the present invention.

[0035] Figure 2 It is a schematic structural view of the variable cycle engine in the low bypass ratio mode according to an embodiment of the present invention.

[0036] Figure 3 It is a schematic structural view of the guide vane ring according to an embodiment of the present invention, where a is the open state and b is the closed state.

[0037] Figure 4 It is a schematic structural view of the brake according to an embodiment of the present invention, where a is the non-braking state and b is the braking state.

[0038] Reference numerals: 10, first compressor; 11, first bypass duct; 12, first guide vane ring; 121, first guide vane; 122, first rotating shaft; 13, first valve; 20, second compressor; 21, second bypass duct; 22, second guide vane ring; 23, second valve; 30, low-pressure turbine; 31, first shaft; 40, high-pressure turbine; 41, second shaft; 50, fan; 61, first differential; 62, first transmission shaft; 63, brake; 71, second differential; 72, second transmission shaft; 80, combustion chamber; 90, tail nozzle. Detailed Embodiments

[0039] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant content and do not limit the present invention. Additionally, it should be noted that for the sake of description, only the parts related to the present invention are shown in the drawings.

[0040] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and embodiments.

[0041] The performance of a jet aviation gas turbine engine is closely related to cycle parameters such as bypass ratio and pressure ratio. To ensure better overall matching and a wider mission adaptability, a larger bypass ratio requires a larger pressure ratio to adapt to low-speed flight, while a smaller bypass ratio requires a smaller pressure ratio to adapt to high-speed flight.

[0042] For fighter jets, the ability to fly both subsonically and supersonically needs to be considered simultaneously. If an engine with a fixed bypass ratio is used, its combat performance will be limited. For example, the fuel consumption during subsonic and supersonic cruise is relatively high, and the ceiling and flight speed are restricted. Developing a variable cycle aeroengine with a variable bypass ratio can significantly improve the performance of combat aircraft.

[0043] Existing variable cycle engine solutions cannot effectively improve the wide-range matching of the engine itself and its wide-range adaptability to missions.

[0044] Please refer to Figures 1 - 2 As shown, an embodiment of the present invention provides a variable cycle engine, including a first compressor 10, a second compressor 20, a high-pressure turbine 40, a low-pressure turbine 30, and an air pushing device for supplying air to the first compressor 10 or the second compressor 20; the low-pressure turbine 30 is drivingly connected to the air pushing device through a first shaft 31; the engine has a first bypass duct 11 on one side of the first compressor 10 and a second bypass duct 21 on one side of the second compressor 20, and the flow area of the first bypass duct 11 is larger than that of the second bypass duct 21; the diameter of the first compressor 10 is smaller than that of the second compressor 20, and the pressure ratio of the first compressor 10 is greater than that of the second compressor 20; when the engine is in the large bypass ratio mode, the high-pressure turbine 40 is drivingly connected to the first compressor 10 through a second shaft 41, and the driving connection between the high-pressure turbine 40 and the second compressor 20 is disconnected; when the engine is in the small bypass ratio mode, the high-pressure turbine 40 is drivingly connected to the second compressor 20 through a second shaft 41, and the driving connection between the high-pressure turbine 40 and the first compressor 10 is disconnected.

[0045] Due to the small diameter of the first compressor 10 and the larger flow area of its corresponding first bypass duct 11 compared to that of the second bypass duct 21, the pressure ratio of the first compressor 10 is also greater than that of the second compressor 20. Therefore, when the first compressor 10 operates alone, the engine is in the high bypass ratio mode, that is, a large bypass ratio, a small flow rate, and a large pressure ratio; correspondingly, when the second compressor 20 operates alone, the engine is in the low bypass ratio mode, that is, a small bypass ratio, a large flow rate, and a small pressure ratio. The high-pressure turbine 40 is drivingly connected or disconnected from the first compressor 10 and the second compressor 20 through the second shaft 41, and can be switched between the first compressor 10 and the second compressor 20, enabling the engine to perform well during both subsonic and supersonic flights, greatly improving the wide-range matching of the engine body and the wide-range adaptability to missions.

[0046] In actual use, the low-pressure turbine drives the air pushing device through the first shaft 31 to supply air to the compressor. When the engine is in the high bypass ratio mode, please refer to Figure 1 As shown, where the dotted arrows indicate the air flow path in the engine. The high-pressure turbine 40 drives the first compressor 10 to rotate and do work through the second shaft 41. At this time, the high-pressure turbine 40 is drivingly disconnected from the second compressor 20, and the second compressor 20 does not operate. The air from the air pushing device enters the first compressor 10 and its corresponding first bypass duct 11. Among them, the air entering the first compressor 10 is discharged through the combustion chamber 80, the high-pressure turbine 40, the low-pressure turbine 30, and the tail pipe 90; while the air entering the first bypass duct 11 is discharged through the tail pipe 90. In this mode, both the bypass ratio and the total pressure ratio are relatively large, with characteristics such as low subsonic fuel consumption and large thrust, and it is suitable for use during subsonic flight.

[0047] When the engine is in the low bypass ratio mode, please refer to Figure 2 As shown, where the dotted arrows indicate the air flow path in the engine. The high-pressure turbine 40 drives the second compressor 20 to rotate and do work through the second shaft 41. At this time, the high-pressure turbine 40 is drivingly disconnected from the first compressor 10, and the first compressor 10 does not operate. The air from the air pushing device enters the second compressor 20 and its corresponding second bypass duct 21. Among them, 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 pipe 90; while the air entering the second bypass duct 21 is discharged through the tail pipe 90. In this mode, both the bypass ratio and the total pressure ratio of the engine are relatively small, with characteristics such as a large maximum Mach number in extreme flight, large supersonic thrust, and low fuel consumption, and it is suitable for use during supersonic flight.

[0048] It can be understood that in order to obtain a large pressure ratio for the first compressor 10, the more stages and the longer the length of the first compressor 10, the larger the pressure ratio it can obtain. Exemplarily, Figure 1The number of stages of the first compressor 10 therein is 5. In order to obtain a small pressure ratio for the second compressor 20, the fewer the number of stages of the second compressor 20, the shorter its length, and the smaller the pressure ratio it can obtain. Exemplarily, Figure 1 the number of stages of the second compressor 20 therein is 3. Thereby, the wide-range matching performance of the variable cycle engine and the wide-range adaptability to missions are improved, enabling the engine to exhibit excellent performance during both subsonic and supersonic flights.

[0049] To achieve efficient air utilization, in some embodiments, the engine further includes a first on-off device for controlling the air entering the first compressor 10 and the first bypass duct 11, and a second on-off device for controlling the air entering the second compressor 20 and the second bypass duct 21; when the engine is in the high bypass ratio mode, the first on-off device is opened and the second on-off device is closed; that is, the air flow through the second compressor 20 and the second bypass duct 21 is blocked, and all the air from the air propulsion device enters the first compressor 10 and the first bypass duct 11.

[0050] 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, that is, the air flow through the first compressor 10 and the first bypass duct 11 is blocked, and all the air from the air propulsion device enters the second compressor 20 and the second bypass duct 21.

[0051] The specific forms of the above-mentioned first on-off device and second on-off device are diverse, as long as they can block the air flow.

[0052] For example, the first on-off device includes a first guide vane ring 12 coordinated with the inlet end of the first compressor 10, and a first valve 13 provided at the end of the first bypass duct 11 near the tail nozzle; when the first guide vane ring 12 is closed, it completely covers the annular inlet of the inlet end of the first compressor 10, thereby preventing air from entering the first compressor, and at the end of the first bypass duct 11 near the tail nozzle, that is, at a position with a smaller size, a first valve 13 is provided. Exemplarily, an ejector valve is adopted. When it is opened, the direction of the ejected gas is consistent with the ejection direction of the first bypass duct 11. Please refer to Figure 1 the ejection state when the first valve 13 is opened in

[0053] The second on-off device adopts a structure similar to that of the first on-off device. For example, the second on-off device includes a second guide vane ring 22 coordinated with the inlet end of the second compressor 20, and a second valve 23 provided at the end of the second outer duct 21 close to the tail nozzle. When the second guide vane ring 22 is closed, it completely covers the annular inlet at the inlet end of the second compressor 20, thereby preventing air from entering the second compressor 20. The second valve 23 is provided at the end of the second outer duct 21 close to the tail nozzle, that is, at a position with a smaller size. For example, an ejection valve is used. When it is opened, the direction of the ejected gas tends to be consistent with the ejection direction of the second outer duct 21. Please refer to Figure 2 The injection state when the second valve 23 is opened.

[0054] Exemplarily, the structures of the first guide vane ring 12 and the second guide vane ring 22 are similar. The first guide vane ring 12 includes a plurality of first guide vanes 121 distributed circumferentially along the inlet end of the first compressor 10, and a plurality of first rotating shafts 122 provided on the first compressor 10, and each first guide vane is movably connected to the corresponding rotating shaft; when the engine is in a small bypass ratio mode, each first guide vane is used to block the inlet end of the first compressor 10; the second guide vane ring 22 includes a plurality of second guide vanes distributed circumferentially along the inlet end of the second compressor 20, and a plurality of second rotating shafts provided on the second compressor 20, and each second guide vane is movably connected to the corresponding second rotating shaft; when the engine is in a large bypass ratio mode, each second guide vane is used to block the inlet end of the second compressor 20.

[0055] The present invention is described by taking the structure of the first guide vane ring 12 as an example. Figure 3 As shown, a is the open state of the first guide vane ring 12, and b is the closed state of the first guide vane ring 12. A plurality of first rotating shafts 122 are arranged at intervals along the circumferential direction of the annular inlet at 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 vane 121 rotates 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, thereby blocking air from entering the first compressor 10; and when the first guide vane ring 12 needs to be opened, the first guide vane 121 rotates around the corresponding first rotating shaft 122 to a position parallel to the incoming flow direction, so that air can smoothly enter the first compressor 10, and the amount of air entering the first compressor 10 is avoided as much as possible. It can be understood that the form of the above-mentioned first guide vane ring 12 can also be similar to a camera shutter to form a structure that blocks air.

[0056] Exemplarily, the structure and working principle of the second guide vane ring 22 of the embodiment of the present invention are the same as those of the first guide vane ring 12 , and are not described in detail herein.

[0057] In some embodiments, the air pushing device in the variable cycle engine of the embodiments of the present invention includes two fans 50. It can be understood that the number of fans is not limited to two, and can also be one fan. In this case, the main shaft of the fan is drivingly connected to the low-pressure turbine 30 through a first shaft 31, thus saving the corresponding transmission shaft. The first shaft 31 is connected to the main shaft of the fan through a coupling, with higher transmission efficiency and relatively simple structure. The number of fans can also be more than two to facilitate the regulation of the air flow entering the compressor. The embodiments of the present invention will be described by taking two fans 50 as an example. Each of the two fans 50 is coordinated with the corresponding first compressor 10 or second compressor 20, that is, the central axis of each fan 50 is generally on the same axis as or parallel to and with a small spacing from the central axis of the corresponding first compressor 10 or second compressor 20. The tails of the two fans 50 are communicated; the tail of each fan 50 is the end close to the inlet end of the corresponding first compressor 10 or second compressor 20; the low-pressure turbine 30 is drivingly connected to the two fans 50 through the first shaft 31 respectively. The first compressor 10 corresponds to one fan 50, and the second compressor 20 corresponds to the other fan 50. There is a channel at the intermediate position between the two compressors at the position between the compressor and the corresponding fan, so that the air of one fan 50 can be mixed into the air provided by the other fan 50 through this channel. The mixed air enters the corresponding first compressor 10 and the corresponding first bypass duct 11, or enters the second compressor 20 and the corresponding second bypass duct 21. Such a design of two juxtaposed fans 50 can significantly improve the intake efficiency of each compressor.

[0058] Considering that the first compressor 10 and the second compressor 20 are generally used separately and their speeds are different. Exemplarily, the variable cycle engine further includes a first differential 61 provided at the end of the second shaft 41 away from the high-pressure turbine 40. The first differential 61 is drivingly connected to the first compressor 10 and the second compressor 20 through corresponding first transmission shafts 62 respectively; a brake 63 is provided on each first transmission shaft 62, and each brake 63 is used to control 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 do work and the other compressor completely stop. In order to control the stopped compressor, a brake 63 is provided on the first transmission shaft 62 of the first differential 61 and the corresponding compressor, or on the main shaft of the corresponding compressor, and the rotation or stop of the corresponding compressor is controlled by the opening and closing of the brake 63.

[0059] Since the transmission devices and braking devices of the two compressors are similar, the embodiments of the present invention will be described by taking the transmission device and braking device of the first compressor as an example. Please refer to Figure 4As shown, one end of the first transmission shaft 62 is connected to the first differential 61, and the other end is connected to the main shaft of the first compressor 10 through a pair of bevel gear pairs. A brake 63 is provided on the first transmission shaft 62. When the engine is in the high bypass ratio mode, the brake 63 is in the open state( Figure 4 a), at this time the first compressor 10 rotates to do work. When the engine is in the low bypass ratio mode, the brake 63 is in the braking state( Figure 4 b), at this time the first compressor 10 stops rotating to do work, and the brake 63 on the first transmission shaft 62 that is drivingly connected to the second compressor 20 is in the open state, and the second compressor 20 rotates to do work.

[0060] In some embodiments, the variable cycle engine further includes a second differential 71 provided at the end of the first shaft 31 away from the low-pressure turbine 30. The second differential 71 is respectively drivingly connected to the two fans 50 through corresponding second transmission shafts 72. Exemplarily, the second transmission shaft 72 is connected to the rotating shaft of the fan 50 in the form of a pair of bevel gear pairs. It can be understood that under normal symmetric intake conditions, the two fans 50 rotate at the same speed in any mode. The purpose of using the second differential 71 is to consider that the intake conditions of the two fans 50 may be asymmetric, thereby increasing the stable operating range of the two fans 50.

[0061] In some embodiments, please refer to Figures 1 - 2 As shown, 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 the power of the high-pressure turbine 40 to the first compressor 10 or the second compressor 20, a transmission shaft sleeving method is adopted, that is, the second shaft 41 has a tubular structure with a hollow cavity, and it is sleeved on the first shaft 31. Both ends of the first shaft 31 extend out of the second shaft 41 and are respectively drivingly connected to the fan and the low-pressure turbine 30. This arrangement of the transmission shaft avoids a complex transmission system, is simple and efficient, and does not occupy too much engine space. Using a tubular shaft also reduces the dead weight of the engine, which is very important for an aeroengine.

[0062] Exemplarily, the variable cycle engine further includes a controller. When the engine is in the high bypass ratio mode, the controller is used to control the second compressor 20 to stop rotating, and the second guide vane ring 22 and the second valve 23 are closed. Specifically, the controller is communicatively connected to the corresponding brake 63 of the second compressor 20, and is also communicatively connected to the second guide vane ring 22 and the second valve 23. When the system receives a request for the high bypass ratio mode, 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 the air completely flows to the first compressor 10 and the corresponding first bypass duct 11, and the first compressor 10 rotates to do work.

[0063] When the engine is in the small bypass ratio mode, the controller is used to control 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 communicatively connected to the corresponding brake 63 of the first compressor 10, and is also communicatively connected to the first guide vane ring 12 and the first valve 13. When the system receives the need for the small bypass ratio mode, the controller respectively controls the corresponding brake 63 to brake, and controls the first guide vane ring 12 and the first valve 13 to close, so that the air completely flows to the second compressor 20 and the corresponding second bypass duct 21, causing the second compressor 20 to rotate and do work.

[0064] In addition, the above components are the main key components of the variable cycle engine. Other components such as the housing, bearings, oil seals, combustion chambers, and tail nozzles are not listed one by one, and their functions are the inherent functions of each component.

[0065] The embodiment of the present invention also provides an aircraft, including the above variable cycle engine. For the specific function implementation of the aircraft provided in this embodiment, please refer to the description of the above variable cycle engine, which will not be elaborated here.

[0066] It should be noted that the variable cycle engine of the present invention can be applied to other vehicles that require power, such as gas turbines, automobiles, ships, airships, etc.

[0067] In the description of this specification, the description with reference to terms such as "one embodiment / way", "some embodiments / ways", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments / ways or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments / ways or examples described in this specification and the features of different embodiments / ways or examples.

[0068] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0069] Those skilled in the art should understand that the above embodiments are only for clearly explaining the present invention and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications can be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A variable cycle engine, characterized in that, It includes a first compressor, a second compressor, a high-pressure turbine, a low-pressure turbine, and an air pushing device for supplying air to the first compressor or the second compressor; The low-pressure turbine is drivingly connected to the air pushing device through a first shaft; The engine has a first bypass duct on one side of the first compressor and a second bypass duct on one side of the second compressor, and the flow area of the first bypass duct is larger than that of the second bypass duct; The diameter of the first compressor is smaller than that of the second compressor, and the pressure ratio of the first compressor is greater than that of the second compressor; When the engine is in the high bypass ratio mode, the high-pressure turbine is drivingly connected to the first compressor through a second shaft, and the high-pressure turbine is disconnected from the second compressor; When the engine is in the low bypass ratio mode, the high-pressure turbine is drivingly connected to the second compressor through a second shaft, and the high-pressure turbine is disconnected from the first compressor.

2. The variable cycle engine according to claim 1, characterized in that, The engine further includes a first on-off device for controlling air to enter the first compressor and the first bypass duct, and a second on-off device for controlling air to enter the second compressor and the second bypass duct; When the engine is in the high bypass ratio mode, the first on-off device is opened and the second on-off device is closed; 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.

3. The variable cycle engine according to claim 2, characterized in that, The first on-off device includes a first guide vane ring coordinated with the inlet end of the first compressor, and a first valve provided at the end of the first bypass duct close to the tail nozzle; The second on-off device includes a second guide vane ring coordinated with the inlet end of the second compressor, and a second valve provided at the end of the second bypass duct close to the tail nozzle.

4. The variable cycle engine according to any one of claims 1-3, characterized in that, The air pushing device includes two fans, each fan being coordinated with the corresponding first compressor or second compressor, and the tails of the two fans are communicated; The tail of each fan is the end close to the inlet end of the corresponding first compressor or second compressor; The low-pressure turbine is drivingly connected to the two fans through the first shaft respectively.

5. The variable cycle engine according to claim 3, characterized in that, The engine further includes a first differential provided at the end of the second shaft away from the high-pressure turbine, and the first differential is drivingly connected to the first compressor and the second compressor through corresponding first transmission shafts respectively; A brake is provided on each first transmission shaft, and each brake is used to control the corresponding first compressor or second compressor to stop rotating.

6. The variable cycle engine according to claim 4, characterized in that, The engine further includes a second differential provided at the end of the first shaft away from the low-pressure turbine, and the second differential is drivingly connected to the two fans through corresponding second transmission shafts respectively.

7. The variable cycle engine according to claim 4, characterized in that, The second shaft is a tubular shaft, and the second shaft is sleeved outside the first shaft.

8. The variable cycle engine according to claim 3, characterized in that, The first guide vane ring includes a plurality of first guide vanes circumferentially distributed along the inlet end of the first compressor, and a plurality of first rotating shafts provided on the first compressor, and each first guide vane is movably connected to the corresponding rotating shaft; When the engine is in the small bypass ratio mode, each of the first guide vanes is used to block the inlet end of the first compressor; and / or, The second guide vane ring includes a plurality of second guide vanes circumferentially distributed along the inlet end of the second compressor, and a plurality of second rotating shafts provided on the second compressor, and each of the second guide vanes is movably connected to the corresponding second rotating shaft; When the engine is in the large bypass ratio mode, each of the second guide vanes is used to block the inlet end of the second compressor.

9. The variable cycle engine according to claim 5, characterized in that, The engine further includes a controller. When the engine is in the large bypass ratio mode, the controller is used to control the second compressor to stop rotating, and the second guide vane ring and the second valve are closed; When the engine is in the small bypass ratio mode, the controller is used to control the first compressor to stop rotating, and the first guide vane ring and the first valve are closed.

10. An aircraft, characterized in that, The aircraft includes the variable cycle engine according to any one of claims 1-9.

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