An adaptive engine with adjustable stator in the last stage of the fan

Abstract

The present invention provides an adaptive engine with an adjustable fan stator in the final stage, comprising an adaptive fan located within the inlet casing. The adaptive fan is used to adjust the bypass ratio of the adaptive engine and includes an adaptive rear fan disposed behind the airflow of the front fan and located within the front end of a second diverter ring. The adaptive rear fan includes at least one stage of rear fan blades, each stage of which includes a rear fan rotor and a rear fan stator. The rear fan stator of the final stage of the rear fan blades is an adjustable fan stator, which is rotatably fixed to the second diverter ring via an actuating mechanism. The adaptive engine designed in the present invention can achieve bypass ratio adjustment by the adaptive fan while reducing the axial length, weight, and number of parts of the fan components.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine design, in particular to an adaptive engine with an adjustable fan last-stage stator. Background Art

[0002] Currently, with the continuous development and advancement of aviation engine design technology, the next generation of military fighter jets will be designed to achieve higher supersonic cruise Mach numbers and longer combat radiuses. Military fighter jets utilize adaptive engines. Compared to conventional turbofan engines, these engines can achieve wide-range adjustment of thermodynamic cycle parameters through geometric adjustments of key components. This results in higher specific thrust in supersonic cruise conditions and lower fuel consumption in subsonic cruise conditions. The adaptive fan is a key geometrically adjustable component of the adaptive engine. Through certain adjustments, it can vary the airflow into the engine's secondary bypass, thereby adjusting the bypass ratio.

[0003] At present, the adaptive fan components of existing adaptive engines are composed of a front fan and a rear fan. The front fan is designed with a stator, and the rear fan is composed of adjustable guide vanes, a rotor and a stator. By adjusting the rear fan guide vanes, the flow rate flowing into the rear fan and the second outer duct is changed to achieve the adjustment of the bypass ratio. However, since a fan stator (including the front fan stator and the rear fan adjustable guide vanes) is provided between the front fan and the rear fan, the axial length of the fan along the airflow direction, the weight of the engine, the number of engine parts, etc. will increase, causing problems contrary to the development direction of lightweight and high reliability of the engine. In addition, the radial height of the installation position of the rear fan adjustable guide vanes is narrow, which makes the design of the actuating mechanism of the rear fan adjustable guide vanes difficult and is not conducive to the subsequent maintenance of the engine.

[0004] Therefore, it is necessary to improve the existing adaptive engine Summary of the Invention

[0005] In response to the adverse effects of existing adaptive engine fan components such as increased axial length along the airflow direction, increased engine weight, and increased engine parts, the present invention designs an adaptive engine with adjustable fan last-stage stator, which can realize adaptive fan adjustment of the bypass ratio while controlling the axial length of the fan components along the airflow direction, engine weight, and the number of engine parts without significantly increasing.

[0006] The technical solution for achieving the purpose of the invention is as follows: an adaptive engine with an adjustable fan final stage stator, comprising an adaptive fan located in an inlet section casing, the adaptive fan being used to adjust the bypass ratio of the adaptive engine, and comprising an adaptive rear fan, the adaptive rear fan being arranged behind the airflow of the front fan and located in a flow channel formed by a second diverter ring and a hub;

[0007] The adaptive rear fan includes at least one stage of rear fan blades, each stage of the rear fan blades includes a rear fan rotor and a rear fan stator, and the rear fan stator of the rear fan blades of the last stage is an adjustable fan stator, and the adjustable fan stator is rotated and fixed on the second diverter ring through an actuating mechanism.

[0008] Furthermore, the actuating mechanism is located in the second diverter ring, and the radial height of the actuating mechanism is smaller than the radial height of the position where the actuating mechanism is set on the second diverter ring.

[0009] Furthermore, the distance between the maximum thickness position and the leading edge position on the rear fan rotor is defined as a, the chord length of the rear fan rotor is defined as b, and when the ratio range of a to b is (35 to 50):100, the flow margin range of the adaptive rear fan is 10 to 20°.

[0010] Furthermore, the distance between the maximum thickness position and the leading edge position on the rear fan rotor is defined as a, the chord length of the rear fan rotor is defined as b, the ratio range of a to b is (35~50):100, and when the angle of attack of the rear fan rotor is in the range of -15° to +5°, the flow margin range of the adaptive rear fan is 10~20°.

[0011] Furthermore, when the adjustable fan stator rotates 20° in the reverse direction, the bypass ratio of the adaptive engine increases by 50% to 100%; when the adjustable fan stator rotates 10° in the forward direction, the bypass ratio of the adaptive engine decreases by 10% to 40%.

[0012] Furthermore, the adaptive rear fan is a first-stage rear fan blade.

[0013] Furthermore, the front fan is arranged in the inlet section casing and is located in front of the airflow of the second diverter ring;

[0014] The front fan includes at least one level of front fan blades, and each level of the front fan blades includes a front fan rotor and a front fan stator. The front fan rotor is fixed on the wheel disc, and the front fan stator is fixed on the inner wall of the inlet section casing.

[0015] Preferably, the front fan further includes an adjustable guide vane, which is located in front of the airflow of the first-stage front fan blades, and the adjustable guide vane is rotatably fixed on the inner wall of the inlet section casing.

[0016] Compared with the prior art, the beneficial effects of the present invention are: the adaptive engine with adjustable fan last stage stator designed by the present invention, on the one hand, reduces the design difficulty of the actuating mechanism of the adjustable guide vanes or adjustable stator blades, and the actuating mechanism is easier to arrange and maintain; on the other hand, it can increase the engine bypass ratio adjustment range; thirdly, the setting of the adjustable guide vanes between the front fan and the rear fan is removed, and the rear fan stator of the rear fan blades of the last stage is designed as an adjustable fan stator, which can reduce one row of blades (i.e., the adjustable guide vanes between the front fan and the rear fan), thereby reducing the axial length, weight and number of parts of the fan, which is beneficial to engine weight reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0018] Figure 1 Schematic diagram of the structure of an adaptive engine with adjustable fan final stage stator in a specific embodiment;

[0019] Figure 2 Schematic diagram of the distance a between the maximum thickness position and the leading edge position on the rear fan rotor, and the chord length b of the rear fan rotor in a specific embodiment;

[0020] Figure 3 for Figure 2 Schematic diagram of the rear fan rotor blade shape when a:b=35:100 and a:b=50:100;

[0021] Figure 4 A characteristic curve of pressure ratio-flow rate of a rear fan rotor of a rear fan of an adaptive engine at 90% speed in a specific embodiment;

[0022] Figure 5 Schematic diagram of the adjustment of the adjustable fan stator of the adaptive engine in a specific embodiment, with a reverse rotation of 20° and a forward rotation of 10°;

[0023] Among them, 1. Front fan; 1-1. Front fan rotor; 1-2. Front fan stator; 1-3. Adjustable guide vanes; 3. Adaptive fan; 4. Rear fan rotor; 5. Adaptive rear fan; 6. Rear fan stator; 7. First bypass ring; 8. Second duct; 9. First duct; 10. Rear duct ejector; 11. duct nozzle; 12. Second bypass ring; 13. Actuator; 14. Compressor; 15. Main combustion chamber; 16. High-pressure turbine; 17. Low-pressure turbine; 18. Afterburner; 19. Main nozzle. DETAILED DESCRIPTION

[0024] 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 the description proceeds. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements fall within the scope of protection of the present invention.

[0025] This embodiment discloses an adaptive engine with adjustable fan final stage stator. Figure 1 As shown, the adaptive engine includes an adaptive fan 3, a first diverter ring 7, a second outer duct 8, a first outer duct 9, a rear duct ejector 10, an outer duct nozzle 11, a second diverter ring 12, a compressor 14, a main combustion chamber 15, a high-pressure turbine 16, a low-pressure turbine 17, an afterburner 18, and a main nozzle 19. The positions and connection relationships of the above components are the same as those of the existing turbine engine, and they will not be described one by one here.

[0026] Among them, Figure 1 As shown, the adaptive fan 3 is located within the inlet section of the casing. It is used to adjust the bypass ratio of the adaptive engine and includes a front fan 1 and a rear fan 5. The adaptive rear fan 5 is positioned behind the airflow of the front fan 1 and within the flow path formed by the second diverter ring 12 and the hub. The adaptive fan adjusts the bypass ratio of the adaptive engine by adjusting the ratio of air entering the casing through the front fan 1 and adjusting the ratio of air entering the rear fan 5 and the second outer bypass 8 based on demand to achieve the desired bypass ratio.

[0027] In one structure of the above-mentioned adaptive rear fan 5, the adaptive rear fan 5 includes at least one level of rear fan blades, such as Figure 1 As shown, each stage of the rear fan blades includes a rear fan rotor 4 and a rear fan stator 6, and the rear fan stator 6 of the rear fan blades of the last stage is an adjustable fan stator, which is rotatably fixed to the second diverter ring 12 via an actuating mechanism 13. In order to reduce the axial length, weight and number of parts of the fan, which is beneficial to the purpose of reducing the weight of the engine, as shown in FIG. Figure 1 As shown, in this embodiment, the adaptive rear fan 5 is preferably selected as the first-stage rear fan blade. It should also be noted that in this embodiment, each stage has multiple rear fan rotors 4 and rear fan stators 6. The multiple rear fan rotors 4 are evenly arranged on the wheel disc, and the multiple rear fan stators 6 are evenly arranged circumferentially on the inner wall of the second diverter ring 12.

[0028] In an improved embodiment of the adaptive rear fan 5, in order to meet the layout requirements of the actuating mechanism 13, the actuating mechanism 13 is located in the second diverter ring 12, and the radial height of the actuating mechanism 13 is less than the radial height of the position where the actuating mechanism 13 is set on the second diverter ring 12; for example, when the radial height of the actuating mechanism 13 is 6 mm, the radial height of the position where the actuating mechanism 13 is installed on the second diverter ring 12 is required to be 7 to 10 mm, preferably 8 mm.

[0029] When the rear fan stator 6 of the rear fan blades of the final stage is set as an adjustable fan stator, the rear fan rotor 4 needs to be adaptively adjusted. In this specific embodiment, a wide flow margin design concept is adopted for the rear fan rotor 4, so that the adaptive rear fan 5 can work stably under the condition of large flow capacity changes. This specific embodiment achieves the flow margin range of the adaptive rear fan 5 to be 10-20° through the following three measures:

[0030] One method is: define the distance between the maximum thickness position and the leading edge position on the rear fan rotor as a, define the chord length of the rear fan rotor as b, and in the existing general design, the ratio range of a to b is (20-30):100. At this time, the flow margin range of the rear fan is 5-10°. In the present invention, Figure 2 and Figure 3 As shown, the ratio range of a to b is (35-50):100, and the flow margin range of the adaptive rear fan 5 is 10-20°.

[0031] The second method is: in the existing general design, the attack angle range of the rear fan rotor 4 is ±5°, and the flow margin range of the rear fan is 5 to 10°. In the present invention, the attack angle range of the rear fan rotor 4 is made to be -15° to +5°, and the flow margin range of the adaptive rear fan 5 is 10 to 20°.

[0032] The third method is a combination of the first method and the second method, that is, when the ratio range of a and b is (35~50):100, and the rear fan rotor attack angle range is -15°~+5°, the flow margin range of the adaptive rear fan is 10~20°.

[0033] See for example Figure 4 The figure shows the pressure ratio-flow characteristic curve of the rear fan rotor 4 of the adaptive rear fan 5 at 90% speed, which is significantly higher than that of the conventional design, laying the foundation for the stable operation of the rear fan when the adjustable fan stator is adjusted.

[0034] The above structure of the fan last stage stator can be adjusted adaptive engine, such as Figure 5The figure shows the blade shape of the rear fan rotor 4 and the adjustable fan stator of the adaptive rear fan 5 at 50% blade height in a 0.2 small split state. When the adjustable fan stator rotates 20° in the reverse direction, the bypass ratio of the adaptive engine increases by 50% to 100%, while when the adjustable fan stator rotates 10° in the forward direction, the bypass ratio of the adaptive engine decreases by 10% to 40%. In this specific embodiment, when viewed in the direction of flight of the aircraft, the rear fan rotor 4 (or the front fan rotor 1-1) rotates clockwise, and when viewed from the high radius position to the low radius position of the adjustable fan stator (or the front fan stator 1-2, the adjustable guide vanes 1-3), the adjustable fan stator rotates in the reverse direction (also referred to as counterclockwise) about the stacking axis to close the adjustment angle, and rotates in the forward direction (also referred to as clockwise) about the stacking axis to open the adjustment angle. The adjustable fan stator can be closed or opened based on the initial adjustment angle.

[0035] In one structure of the above-mentioned adaptive rear fan 5, as Figure 1 As shown, the front fan 1 is arranged in the inlet section casing and is located in front of the airflow of the second diverter ring 12. The front fan 1 includes at least one stage of front fan blades, and each stage of the front fan blades includes a front fan rotor 1-1 and a front fan stator 1-2. The front fan rotor 1-1 is fixed on the wheel disc, and the front fan stator 1-2 is fixed on the inner wall of the inlet section casing. Preferably, as Figure 1 As shown, the front fan further includes adjustable guide vanes 1-3, which are located in front of the airflow of the first-stage front fan blades and are rotatably fixed to the inner wall of the inlet section casing. It should also be noted that in this specific embodiment, each stage has multiple front fan rotors 1-1, front fan stators 1-2, and adjustable guide vanes 1-3. The multiple front fan rotors 1-1 are evenly arranged on the wheel disc, and the multiple front fan stators 1-2 and adjustable guide vanes 1-3 are evenly arranged circumferentially on the inner wall of the inlet section casing.

[0036] In this specific implementation, the process of adaptively adjusting the bypass ratio of the engine is as follows:

[0037] When the adaptive engine requires the adaptive fan to increase the diversion ratio to increase the engine bypass ratio, the adjustable fan stator adjustment angle is gradually closed, the flow capacity of the adaptive fan 5 is reduced, and the airflow inhaled by the front fan 1 flows more into the second outer bypass 8, and then discharged into the atmosphere through the outer bypass nozzle 11.

[0038] When the adaptive engine requires the adaptive fan to reduce the diversion ratio to lower the engine bypass ratio, the adjustable fan stator gradually opens, increasing the flow capacity of the adaptive rear fan 5. More airflow from the front fan 1 flows into the adaptive rear fan 5. When the rear duct ejector 10 is closed, the airflow flowing into the first duct 9 decreases, allowing more airflow from the rear fan to flow into the compressor 14, increasing the engine's core flow capacity and boosting thrust.

[0039] Compared with the prior art, the beneficial effects of the present invention are: the adaptive engine with adjustable fan last stage stator designed by the present invention, on the one hand, reduces the design difficulty of the actuating mechanism of the adjustable guide vanes or adjustable stator blades, and the actuating mechanism is easier to arrange and maintain; on the other hand, it can increase the engine bypass ratio adjustment range; thirdly, the setting of the adjustable guide vanes between the front fan and the rear fan is removed, and the rear fan stator of the rear fan blades of the last stage is designed as an adjustable fan stator, which can reduce one row of blades (i.e., the adjustable guide vanes between the front fan and the rear fan), thereby reducing the axial length, weight and number of parts of the fan, which is beneficial to engine weight reduction.

[0040] 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 in the scope of protection of the present invention.

[0041] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An adaptive engine with an adjustable fan stator in the final stage, comprising an adaptive fan located in an inlet casing, characterized in that: The adaptive fan is used to adjust the bypass ratio of the adaptive engine, and includes an adaptive rear fan, which is arranged behind the airflow of the front fan and is located in the flow channel formed by the second diverter ring and the hub; The adaptive rear fan includes at least one stage of rear fan blades, and each stage of the rear fan blades includes a rear fan rotor and a rear fan stator, and the rear fan stator of the rear fan blades of the last stage is an adjustable fan stator, and the adjustable fan stator is rotated and fixed on the second diverter ring through an actuating mechanism; the front fan includes an adjustable guide vane, and the adjustable guide vane is located in front of the airflow of the first stage front fan blades.

2. The adaptive engine with adjustable fan final stage stator according to claim 1, characterized in that: The actuating mechanism is located in the second diverter ring, and the radial height of the actuating mechanism is smaller than the radial height of the position where the actuating mechanism is provided on the second diverter ring.

3. The adaptive engine with adjustable fan final stage stator according to claim 1, characterized in that: The distance between the maximum thickness position and the leading edge position on the rear fan rotor is defined as a, and the chord length of the rear fan rotor is defined as b. When the ratio range of a to b is (35 to 50):100, the flow margin range of the adaptive rear fan is 10 to 20°.

4. The adaptive engine with adjustable fan final stage stator according to claim 1, characterized in that: The distance between the maximum thickness position and the leading edge position on the rear fan rotor is defined as a, the chord length of the rear fan rotor is defined as b, when the ratio range of a to b is (35~50):100, and the angle of attack range of the rear fan rotor is -15° to +5°, the flow margin range of the adaptive rear fan is 10~20°.

5. The adaptive engine with adjustable fan final stage stator according to claim 1, characterized in that: When the adjustable fan stator rotates 20° in the reverse direction, the bypass ratio of the adaptive engine increases by 50% to 100%; when the adjustable fan stator rotates 10° in the forward direction, the bypass ratio of the adaptive engine decreases by 10% to 40%.

6. The adaptive engine with adjustable fan final stage stator according to claim 1, characterized in that: The adaptive rear fan is a first-stage rear fan blade.

7. The adaptive engine with adjustable fan final stage stator according to claim 1, characterized in that: The front fan is arranged in the inlet section casing and is located in front of the airflow of the second diverter ring; The front fan includes at least one level of front fan blades, and each level of the front fan blades includes a front fan rotor and a front fan stator. The front fan rotor is fixed on the wheel disc, and the front fan stator is fixed on the inner wall of the inlet section casing.

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