Variable cycle engine air entraining structure capable of adjusting axial force of guide vane and rotor

Abstract

The invention belongs to the field of engine design, and particularly relates to a guide vane and rotor axial force adjustable variable cycle engine bleed structure, an adjustable low-pressure turbine guide vane is coaxially connected to the outer side of a low-pressure turbine guider inner ring, and a hollow rotating shaft is arranged in the adjustable low-pressure turbine guide vane; the inner end of the hollow rotating shaft is communicated with the high-low pressure turbine disc cavity, and the outer end is communicated with high-pressure gas generated by a gas compressor; the low-pressure turbine case is arranged on the outer side of the low-pressure turbine rotor, and the outer end of the adjustable low-pressure turbine guide vane is of a hollow structure and is rotationally connected with the low-pressure turbine case. High-pressure gas can enter the high-low pressure turbine disc cavity through the hollow rotating shaft under the closed condition. Bleed air is all limited in the hollow rotating shaft of the guide blade, is not easy to leak and is not influenced by the rotation of the blade, and the bleed air pressure is stable; the entrained air is all limited in the hollow rotating shaft of the guide blade, and the requirement for the area of an entrained air channel can be met only by setting the reasonable inner diameter size of the rotating shaft.

Description

Technical Field

[0001] The present application belongs to the field of engine design, and in particular relates to a variable cycle engine air induction structure with guide vanes and rotor axial force adjustment. Background Art

[0002] Conventional low-bypass-ratio turbofan engines usually use low-pressure turbine guide vanes as the air system flow path to supply air to the high- and low-pressure turbine inter-disk cavity to adjust the axial force of the high and low-pressure rotors. At the same time, the guide vane end is provided with a conformal hole as an air bleed channel.

[0003] The variable cycle turbofan engine adjusts the core engine flow and the power distribution between the high and low pressure turbines by controlling and changing the angle of the low pressure turbine guide vanes. This means that the angle of the guide vanes needs to change with the changes in the engine status and working mode. Usually, an actuator is used for active adjustment, and it works in conjunction with other adjustable variables to achieve the unique mode conversion capability of the variable cycle engine, which can take into account the high thrust and low fuel consumption requirements of the variable cycle engine.

[0004] However, adjusting the angle of the guide blade requires setting a rotating shaft at its end, which conflicts with the conventional design of the conformal hole air duct.

[0005] For a variable cycle turbofan engine with an adjustable low-pressure turbine guide vane angle, if the aspect ratio design and bleed air duct layout of the conventional turbofan engine low-pressure turbine guide vane are used, the following problems will be faced:

[0006] 1) The number of guide blades is relatively large and the thickness is relatively small. The rotating shaft structure at both ends limits the size of the special-shaped holes required for the air bleed channel, and the air bleed channel area does not meet the requirements;

[0007] 2) The guide vane shaft diameter is relatively small, and its ability to withstand the aerodynamic load of the blade and the bending moment and torque caused by the regulating load is weak;

[0008] If the high-pressure turbine rotor opening is used to supply air, the following new problems will arise:

[0009] 1) A large number of vent holes are opened at the high radius of the high-pressure turbine disk, which weakens the strength of the turbine disk and creates a large number of stress concentration points and potential sources of defects;

[0010] 2) The convenient optional air supply source is the compressor outlet air. The air source pressure significantly exceeds the demand, exacerbating performance loss and increasing the sealing pressure difference between the high-vortex rear and low-vortex front cavities on the main channel, increasing leakage; the waste of bleed air source and leakage have a two-fold deterioration in the performance of the entire machine.

[0011] Therefore, how to design a more effective air entrainment structure is a problem that needs to be solved. Summary of the Invention

[0012] The purpose of this application is to provide a variable cycle engine air induction structure with adjustable guide vanes and rotor axial force, so as to solve the problem of conflict between the existing air induction structure design and the conformal hole air induction channel.

[0013] The technical solution of the present application is: a variable cycle engine bleed air structure with adjustable guide vanes and rotor axial force, comprising a high-pressure turbine rotor, a low-pressure turbine guide vane inner ring, adjustable low-pressure turbine guide vanes, a low-pressure turbine guide vane outer ring, a low-pressure turbine casing, and a low-pressure turbine rotor;

[0014] The low-pressure turbine guide vane inner ring is connected between the high-pressure turbine rotor and the low-pressure turbine rotor, the low-pressure turbine guide vane outer ring is arranged on the outside of the adjustable low-pressure turbine guide vane, and the high-pressure and low-pressure turbine disc cavities are formed between the low-pressure turbine guide vane inner ring, the high-pressure turbine rotor and the low-pressure turbine rotor;

[0015] The adjustable low-pressure turbine guide vanes are coaxially connected to the outer side of the inner ring of the low-pressure turbine guide vane. A hollow rotating shaft is provided in the adjustable low-pressure turbine guide vanes. The inner end of the hollow rotating shaft is connected to the high- and low-pressure turbine disc cavities, and the outer end is connected to the high-pressure gas generated by the compressor. The low-pressure turbine casing is arranged on the outer side of the low-pressure turbine rotor. The outer end of the adjustable low-pressure turbine guide vanes is a hollow structure and is rotatably connected to the low-pressure turbine casing.

[0016] The high-pressure gas can enter the high- and low-pressure turbine disc cavities through the hollow rotating shaft in a closed state.

[0017] Preferably, an external air inlet is provided on the outer wall of the low-pressure turbine casing, and the external air is connected to the high-pressure air through a pipeline; an internal air inlet is provided on the side wall of the low-pressure turbine casing close to the adjustable low-pressure turbine guide blade, a buffer cavity is provided between the external air inlet and the internal air inlet, and the internal air inlet is connected to the air shaft.

[0018] Preferably, the outer end of the adjustable low-pressure turbine guide blade is provided with a cylindrical connecting column, the interior of the connecting column is a cavity structure, and the side wall of the connecting column is provided with a plurality of circular holes connected to the external air inlet; the connecting column is rotatably connected to the low-pressure turbine casing.

[0019] Preferably, an adjustable guide vane rocker arm capable of driving the adjustable low-pressure turbine guide vanes to rotate is further provided between the adjustable low-pressure turbine guide vanes and the low-pressure turbine casing; the adjustable guide vane rocker arm is provided with power, which can drive the adjustable low-pressure turbine guide vanes to rotate.

[0020] Preferably, an inner groove is provided at the top of the connecting column, and a lower concave block connected to the inner groove with bolts is provided on the adjustable guide vane rocker arm.

[0021] Preferably, the adjustable low-pressure turbine guide vanes are small aspect ratio guide vanes.

[0022] The variable cycle engine air induction structure with guide vanes and rotor axial force adjustment in this application has the following advantages:

[0023] 1) The bleed air is completely confined inside the hollow shaft of the guide vane, which is not easy to leak and is not affected by the rotation of the blades, and the bleed air pressure is stable;

[0024] 2) The bleed air is completely confined inside the hollow shaft of the guide vane. The bleed air passage area requirement can be met by simply setting a reasonable inner diameter of the shaft.

[0025] 3) Setting a large-diameter hollow shaft can effectively improve the bending and torsion resistance of the low-pressure turbine guide blade shaft, while avoiding excessive coupling with the blade's own cooling air, and can increase the accuracy of simulation and test verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions provided by this application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0027] Figure 1 This is a schematic diagram of the overall structure of this application.

[0028] 1. High-pressure turbine rotor; 2. Low-pressure turbine guide vane inner ring; 3. Adjustable low-pressure turbine guide vanes; 4. Low-pressure turbine guide vane outer ring; 5. Low-pressure turbine casing; 6. Adjustable guide vane rocker arm; 7. Low-pressure turbine rotor; 8. Hollow shaft; 9. External air inlet; 10. Internal air inlet; 11. Buffer chamber; 12. Connecting column. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Regarding the requirement of setting a hollow air bleed channel on the guide vane shaft, the channel size is linearly related to the shaft size and the blade size. Therefore, the channel area A0 on a single blade is related to the square of the blade thickness t, that is,

[0031] A0∝t 2

[0032] For bending and torsional loads, the load-bearing capacity of the same material is related to the section moment of the shaft, that is, to the fourth power of the blade thickness t, that is,

[0033] J0∝t 4

[0034] In order to increase the blade size without causing a significant impact on aerodynamics, the method of keeping the blade density unchanged, reducing the aspect ratio, and increasing the number of blades is adopted. x With Ye Gao H s and axial chord length C x The relationship is: AR x =H s / C x

[0035] Consistency SR x With the grid pitch s and chord length C x The relationship is: SR x =s / C x

[0036] The number of blades n

[0037]

[0038] but

[0039]

[0040]

[0041] Total air bleed area When the size and viscosity of the meridian flow path remain unchanged, D h 、D t 、H s SR x is a constant, the total air bleed area is only related to the aspect ratio AR x Inversely related, a small aspect ratio is beneficial to increasing the total air bleed area.

[0042] Similar to the total bending and torsional capacity

[0043]

[0044] That is, the total bending and torsional resistance is only related to the aspect ratio AR x The cubic coefficient is inversely correlated, and a small aspect ratio is beneficial to improving the bearing capacity of the shaft.

[0045] A variable cycle engine bleed air structure with guide vanes and rotor axial force adjustment, such as Figure 1 As shown, it includes a high-pressure turbine rotor 1, a low-pressure turbine guide vane inner ring 2, adjustable low-pressure turbine guide vanes 3, a low-pressure turbine guide vane outer ring 4, a low-pressure turbine casing 5 and a low-pressure turbine rotor 7.

[0046] The high-pressure turbine rotor 1 and the low-pressure turbine rotor 7 are coaxially arranged, the low-pressure turbine guide inner ring 2 is connected between the high-pressure turbine rotor 1 and the low-pressure turbine rotor 7, the low-pressure turbine guide outer ring 4 is arranged on the outside of the adjustable low-pressure turbine guide blade 3, and the high- and low-pressure turbine disc cavities are between the low-pressure turbine guide inner ring 2, the high-pressure turbine rotor 1 and the low-pressure turbine rotor 7; the adjustable low-pressure turbine guide blade 3 is coaxially connected to the outside of the low-pressure turbine guide inner ring 2, and a hollow rotating shaft 8 is opened in the adjustable low-pressure turbine guide blade 3, the inner end of the hollow rotating shaft 8 is connected to the high- and low-pressure turbine disc cavities, and the outer end is connected to the high-pressure gas generated by the compressor; the low-pressure turbine casing 5 is arranged on the outside of the low-pressure turbine rotor 7, and the outer end of the adjustable low-pressure turbine guide blade 3 is a hollow structure and is rotatably connected to the low-pressure turbine casing 5.

[0047] High-pressure gas can enter the high- and low-pressure turbine disc cavities through the hollow rotating shaft 8 in a closed state.

[0048] Within the engine's operating envelope, the air system is used to guide the high-pressure air generated by the compressor to the disc cavity between the high and low-pressure turbines to ensure the axial force balance of the engine rotor and maintain appropriate axial loads on each thrust bearing.

[0049] The high-pressure gas passes through the hollow shaft 8 and the adjustable low-pressure turbine guide blades 3 into the interior of the hollow shaft 8. The bleed air is completely confined inside the hollow shaft 8, is not easy to leak, and is not affected by the rotation of the low-pressure turbine guide blades. The bleed air pressure is stable, which can effectively avoid the thrust bearing being lightly loaded or even load reversal due to insufficient bleed air pressure.

[0050] Preferably, an external air bleed port 9 is provided on the outer wall of the low-pressure turbine casing 5, which receives high-pressure air through a pipe. An internal air bleed port 10 is provided on the side wall of the low-pressure turbine casing 5 near the adjustable low-pressure turbine guide vanes 3. A buffer chamber 11 is defined between the external air bleed port 9 and the internal air bleed port 10, which is connected to the air shaft. The low-pressure turbine casing 5 delivers high-pressure air to the air shaft through the external air bleed port 9 and the internal air bleed port 10, ensuring stable ventilation while sealing the outer ends of the adjustable low-pressure turbine guide vanes 3, thereby ensuring more stable operation of the adjustable low-pressure turbine guide vanes 3.

[0051] Preferably, a cylindrical connecting post 12 is provided at the outer end of the adjustable low-pressure turbine guide vane 3. The interior of the connecting post 12 is a hollow structure, and the sidewall of the connecting post 12 is provided with multiple circular holes that communicate with the external air inlet 9. The connecting post 12 is rotatably connected to the low-pressure turbine casing 5. The provision of the connecting post 12 achieves a hollow rotating connection and ensures a stable fit between the adjustable low-pressure turbine guide vane 3 and the low-pressure turbine casing 5.

[0052] Preferably, an adjustable guide vane rocker arm 6 capable of driving the adjustable low-pressure turbine guide vanes 3 to rotate is further provided between the adjustable low-pressure turbine guide vanes 3 and the low-pressure turbine casing 5. The adjustable guide vane rocker arm 6 is provided with power, which can drive the adjustable low-pressure turbine guide vanes 3 to rotate.

[0053] Since the adjustable low-pressure turbine guide vanes 3 are adjustable, the shear force, bending moment and torque acting on the shaft are much greater than those of the compressor guide vanes. Therefore, it is recommended to use small aspect ratio guide vanes to improve the shaft load capacity and ensure that it has sufficient bending and torsional resistance.

[0054] Preferably, an inner groove is provided at the top of the connecting column 12, and a lower concave block connected to the inner groove by bolts is provided on the adjustable guide vane rocker arm 6 to ensure a stable connection between the adjustable guide vane rocker arm 6 and the adjustable low-pressure turbine guide blade 3.

[0055] Preferably, the adjustable low-pressure turbine guide vanes 3 are small aspect ratio guide vanes, which are used to improve the bearing capacity of the rotor shaft and ensure that it has sufficient anti-bending and anti-torsion capabilities.

[0056] In addition, the consistency of the low-pressure turbine guide vanes can be adjusted according to the rotation direction of the high and low-pressure rotors. While ensuring the consistency of relevant parameters such as flow capacity, the high and low-pressure rotors rotate at the same time, and the guide vanes have a higher consistency; the high and low-pressure rotors rotate in opposite directions, and the guide vanes have a lower consistency.

[0057] In addition, the inner diameter of the hollow shaft 8 can be determined according to the air system simulation requirements, and the outer diameter of the shaft can be determined according to the strength of the guide blades and the vibration simulation results.

[0058] In summary, this application has the following advantages:

[0059] 1) The bleed air is completely confined inside the hollow shaft of the guide vane, which is not easy to leak and is not affected by the rotation of the blades, and the bleed air pressure is stable;

[0060] 2) The bleed air is completely confined inside the hollow shaft of the guide vane. The bleed air passage area requirement can be met by simply setting a reasonable inner diameter of the shaft.

[0061] 3) Setting a large-diameter hollow shaft can effectively improve the bending and torsion resistance of the low-pressure turbine guide blade shaft, while avoiding excessive coupling with the blade's own cooling air, and can increase the accuracy of simulation and test verification.

[0062] Finally, it should be noted that the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention. Other structures can refer to common designs. In the absence of conflicts, the same embodiment and different embodiments of the present invention can be combined with each other.

[0063] Finally: 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.

Claims

1. A variable cycle engine air induction structure with adjustable guide vanes and rotor axial force, characterized by: It comprises a high-pressure turbine rotor (1), a low-pressure turbine guide vane inner ring (2), adjustable low-pressure turbine guide vanes (3), a low-pressure turbine guide vane outer ring (4), a low-pressure turbine casing (5) and a low-pressure turbine rotor (7); The low-pressure turbine guide vane inner ring (2) is connected between the high-pressure turbine rotor (1) and the low-pressure turbine rotor (7); the low-pressure turbine guide vane outer ring (4) is arranged outside the adjustable low-pressure turbine guide vane (3); and high- and low-pressure turbine disc cavities are formed between the low-pressure turbine guide vane inner ring (2), the high-pressure turbine rotor (1), and the low-pressure turbine rotor (7); The adjustable low-pressure turbine guide blade (3) is coaxially connected to the outer side of the low-pressure turbine guide device inner ring (2); a hollow rotating shaft (8) is provided in the adjustable low-pressure turbine guide blade (3); the inner end of the hollow rotating shaft (8) is communicated with the high- and low-pressure turbine disc cavities, and the outer end is connected to the high-pressure gas generated by the compressor; the low-pressure turbine casing (5) is arranged on the outer side of the low-pressure turbine rotor (7); the outer end of the adjustable low-pressure turbine guide blade (3) is a hollow structure and is rotatably connected to the low-pressure turbine casing (5); The high-pressure gas can enter the high- and low-pressure turbine disc cavities through the hollow rotating shaft (8) in a closed state.

2. The variable cycle engine bleed air structure with guide vanes and rotor axial force adjustment according to claim 1, characterized in that: An external air inlet (9) is provided on the outer wall of the low-pressure turbine casing (5), and the external air inlet is connected to the high-pressure air through a pipeline; an internal air inlet (10) is provided on the side wall of the low-pressure turbine casing (5) close to the adjustable low-pressure turbine guide blade (3), a buffer cavity (11) is provided between the external air inlet (9) and the internal air inlet (10), and the internal air inlet (10) is communicated with the air shaft.

3. The variable cycle engine air bleed structure with guide vanes and rotor axial force adjustment according to claim 2, characterized in that: The outer end of the adjustable low-pressure turbine guide blade (3) is provided with a cylindrical connecting column (12), the interior of the connecting column (12) is a cavity structure, and the side wall of the connecting column (12) is provided with a plurality of circular holes connected to the external air inlet (9); the connecting column (12) is rotatably connected to the low-pressure turbine casing (5).

4. The variable cycle engine air bleed structure with guide vanes and rotor axial force adjustment according to claim 3, characterized in that: An adjustable guide vane rocker arm (6) capable of driving the adjustable low-pressure turbine guide vane (3) to rotate is further provided between the adjustable low-pressure turbine guide vane (3) and the low-pressure turbine casing (5); the adjustable guide vane rocker arm (6) is provided with a power capable of driving the adjustable low-pressure turbine guide vane (3) to rotate.

5. The variable cycle engine bleed air structure with guide vanes and rotor axial force adjustment according to claim 4, characterized in that: An inner groove is provided at the top of the connecting column (12), and a lower concave block connected to the inner groove with bolts is provided on the adjustable guide vane rocker arm (6).

6. The variable cycle engine bleed air structure with guide vanes and rotor axial force adjustment according to claim 1, characterized in that: The adjustable low-pressure turbine guide blades (3) are small aspect ratio guide blades.

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