Variable cycle engine bleed structure for vane and rotor axial force regulation

Abstract

The application belongs to the field of engine design, and particularly relates to a variable cycle engine bleed air structure for adjusting the axial force of a guide vane and a rotor, wherein the adjustable low-pressure turbine guide vane is coaxially connected to the outside of an inner ring of a low-pressure turbine guide vane, 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 a high-low pressure turbine disc cavity, and the outer end of the hollow rotating shaft is connected to high-pressure air generated by a compressor; the low-pressure turbine casing is arranged outside a low-pressure turbine rotor, the outer end of the adjustable low-pressure turbine guide vane is in a hollow structure and rotationally connected to the low-pressure turbine casing; and the high-pressure air can enter the high-low pressure turbine disc cavity through the hollow rotating shaft in a closed condition. The bleed air is entirely limited in the hollow rotating shaft of the guide vane, is not easy to leak, is not affected by the rotation of the guide vane, and has stable bleed air pressure; and the bleed air is entirely limited in the hollow rotating shaft of the guide vane, so that the bleed air passage area requirement can be met by only arranging a reasonable inner diameter size of the rotating shaft.

Description

Technical Field

[0001] This application belongs to the field of engine design, and specifically relates to a bleed air structure for a variable cycle engine with guide vanes and rotor axial force adjustment. Background Technology

[0002] Conventional low-bypass turbofan engines typically use low-pressure turbine guide vanes as airflow channels to supply air to the high- and low-pressure turbine disk chambers to adjust the axial force of the high- and low-pressure rotors. At the same time, the guide vane tips are provided with conformal holes as bleed air channels.

[0003] Variable cycle turbofan engines adjust the flow rate of the core engine 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 engine state and operating mode. Usually, an actuation mechanism is used for active adjustment, working in conjunction with other adjustable variables to achieve the mode switching capability unique to variable cycle engines, which can meet the requirements of high thrust and low fuel consumption of variable cycle engines.

[0004] Adjusting the angle of the guide vane requires a rotating shaft at its end, which conflicts with the conformal orifice air intake channel in traditional design.

[0005] For variable-cycle turbofan engines with adjustable low-pressure turbine guide vane angles, if the aspect ratio design and bleed air passage arrangement of the conventional turbofan engine's low-pressure turbine guide vane are used, the following problems will be encountered:

[0006] 1) The number of guide vanes is relatively large and the thickness is relatively small. The structure of the rotating shaft at both ends limits the size of the irregular holes required for the air intake channel, and the area of ​​the air intake channel does not meet the requirements.

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

[0008] If a high-pressure turbine rotor with an opening for gas supply is used, the following new problems will arise:

[0009] 1) The high-pressure turbine disk has a large number of ventilation holes at the high radius position, which weakens the strength of the turbine disk and brings 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, which aggravates the performance loss and increases the sealing pressure difference between the high scroll plate rear chamber and the low scroll plate front chamber and the main flow channel, increasing leakage. The waste of air source and leakage have a deteriorating effect on the overall performance of the machine in two aspects.

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

[0012] The purpose of this application is to provide a bleed air structure for a variable cycle engine with adjustable guide vanes and rotor axial force, in order to solve the problem of conflict between existing bleed air structure designs and conformal orifice bleed air channels.

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

[0014] The inner ring of the low-pressure turbine guide is connected between the high-pressure turbine rotor and the low-pressure turbine rotor, and the outer ring of the low-pressure turbine guide is located on the outside of the adjustable low-pressure turbine guide vane. The space between the inner ring of the low-pressure turbine guide, the high-pressure turbine rotor, and the low-pressure turbine rotor is a high- and low-pressure turbine disk cavity.

[0015] The adjustable low-pressure turbine guide vane is coaxially connected to the outer side of the inner ring of the low-pressure turbine guide vane. A hollow rotating shaft is provided inside the adjustable low-pressure turbine guide vane. The inner end of the hollow rotating shaft is connected to the high-pressure turbine disk cavity, and the outer end is connected to the high-pressure gas generated by the compressor. The low-pressure turbine casing is located outside the low-pressure turbine rotor. The outer end of the adjustable low-pressure turbine guide vane 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 disk cavity through the hollow rotating shaft in a closed state.

[0017] Preferably, the outer wall of the low-pressure turbine casing is provided with an external air intake port, and the external air intake is connected to the high-pressure gas through a pipeline; the side wall of the low-pressure turbine casing near the adjustable low-pressure turbine guide vanes is provided with an internal air intake port, a buffer cavity is provided between the external air intake port and the internal air intake port, and the internal air intake port is connected to the air shaft.

[0018] Preferably, the outer end of the adjustable low-pressure turbine guide vane is provided with a cylindrical connecting post, the connecting post having a hollow internal structure, and multiple circular holes communicating with the external air intake are provided on the side wall of the connecting post; the connecting post 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 vane to rotate is further provided between the adjustable low-pressure turbine guide vane and the low-pressure turbine casing; the adjustable guide vane rocker arm is provided with a power source capable of driving the adjustable low-pressure turbine guide vane to rotate.

[0020] Preferably, the top of the connecting column is provided with an inner groove, and the adjustable guide vane rocker arm is provided with a recessed block that is bolted to the inner groove.

[0021] Preferably, the adjustable low-pressure turbine guide vane is a guide vane with a small aspect ratio.

[0022] The guide vane and rotor axial force adjustment variable cycle engine bleed air structure of this application has the following advantages:

[0023] 1) The bleed air is completely confined inside the hollow shaft of the guide vane, making it difficult to leak and unaffected by the rotation of the vane, resulting in stable bleed air pressure;

[0024] 2) The air intake is entirely confined inside the hollow shaft of the guide vane. Only a reasonable inner diameter of the shaft needs to be set to meet the air intake channel area requirements.

[0025] 3) Setting a large-diameter hollow shaft can effectively improve the bending and torsional resistance of the low-pressure turbine guide vane shaft, while avoiding excessive coupling with the cooling gas of the blade itself, thus increasing the accuracy of simulation and experimental verification. Attached Figure Description

[0026] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely 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 vane; 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 intake; 10. Internal air intake; 11. Buffer chamber; 12. Connecting column. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] For the requirement to install hollow air intake channels on the guide vane shaft, the channel dimensions are linearly related to the shaft dimensions and blade dimensions. Therefore, the channel area A0 on a single blade is related to the square of the blade thickness t, i.e.

[0031] A0∝t 2

[0032] For bearing 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.

[0033] J0∝t 4

[0034] To increase blade size without significantly impacting aerodynamics, a method is adopted that maintains constant blade consistency, reduces the aspect ratio, and increases the number of blades. (Due to the aspect ratio AR...) 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 grid pitch s and chord length C x The relationship is: SR x =s / C x

[0036] And the number of leaves n

[0037]

[0038] but

[0039]

[0040]

[0041] Total air intake area When the meridional flow path size and consistency remain constant, D h D t H s SR x If it is a constant, then the total air intake area is only related to the aspect ratio AR. x The correlation is negative; a smaller aspect ratio is beneficial for increasing the total air intake area.

[0042] Similarly, there are overall resistance to bending and torsion.

[0043]

[0044] That is, the total bending and torsional resistance is only related to the aspect ratio AR. x The cubic inverse correlation indicates that a small aspect ratio is beneficial for improving the load-bearing capacity of the bearing.

[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 inner ring 2, an adjustable low-pressure turbine guide vane 3, a low-pressure turbine guide 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 inner ring 2 of the low-pressure turbine guide is connected between the high-pressure turbine rotor 1 and the low-pressure turbine rotor 7. The outer ring 4 of the low-pressure turbine guide is located outside the adjustable low-pressure turbine guide vane 3. The high-pressure turbine disk cavity is located between the inner ring 2 of the low-pressure turbine guide, the high-pressure turbine rotor 1 and the low-pressure turbine rotor 7. The adjustable low-pressure turbine guide vane 3 is coaxially connected to the outer side of the inner ring 2 of the low-pressure turbine guide. A hollow rotating shaft 8 is opened inside the adjustable low-pressure turbine guide vane 3. The inner end of the hollow rotating shaft 8 is connected to the high-pressure turbine disk cavity, and the outer end is connected to the high-pressure gas generated by the compressor. The low-pressure turbine casing 5 is located outside the low-pressure turbine rotor 7. The outer end of the adjustable low-pressure turbine guide vane 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 disk cavity through the hollow rotating shaft 8 under closed conditions.

[0048] Within the engine's operating envelope, the air system draws high-pressure air generated by the compressor to the high- and low-pressure turbine disk cavity to balance the axial force of the engine rotor and maintain appropriate axial loads on each thrust bearing.

[0049] High-pressure gas passes through the hollow shaft 8 and the adjustable low-pressure turbine guide vane 3 into the hollow shaft 8. All the bleed gas is confined inside the hollow shaft 8, making it difficult to leak and unaffected by the rotation of the low-pressure turbine guide vane. The bleed gas pressure is stable, which can effectively avoid the thrust bearing being lightly loaded or even the load reversing due to insufficient bleed gas pressure.

[0050] Preferably, the low-pressure turbine casing 5 has an external air intake port 9 on its outer wall, through which high-pressure gas is introduced via a pipe; an internal air intake port 10 is provided on the side wall of the low-pressure turbine casing 5 near the adjustable low-pressure turbine guide vanes 3, and a buffer chamber 11 is provided between the external air intake port 9 and the internal air intake port 10, with the internal air intake port 10 connected to the air shaft. The low-pressure turbine casing 5 delivers high-pressure gas to the air shaft through the external air intake port 9 and the internal air intake port 10, ensuring stable airflow while sealing the outer end of the adjustable low-pressure turbine guide vanes 3, thus making the operation of the adjustable low-pressure turbine guide vanes 3 more stable.

[0051] Preferably, the outer end of the adjustable low-pressure turbine guide vane 3 is provided with a cylindrical connecting post 12. The connecting post 12 has a hollow internal structure, and multiple circular holes communicating with the external air intake 9 are opened on the side wall of the connecting post 12. The connecting post 12 is rotatably connected to the low-pressure turbine casing 5. The hollow rotatable connection is achieved by the setting of the connecting post 12, while ensuring the stable cooperation 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 is provided between the adjustable low-pressure turbine guide vane 3 and the low-pressure turbine casing 5, which can drive the adjustable low-pressure turbine guide vane 3 to rotate. The adjustable guide vane rocker arm 6 is equipped with a power source that can drive the adjustable low-pressure turbine guide vane 3 to rotate.

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

[0054] Preferably, the top of the connecting column 12 is provided with an inner groove, and the adjustable guide vane rocker arm 6 is provided with a recessed block that is bolted to the inner groove to ensure a stable connection between the adjustable guide vane rocker arm 6 and the adjustable low-pressure turbine guide vane 3.

[0055] Preferably, the adjustable low-pressure turbine guide vane 3 is a guide vane with a small aspect ratio, which is used to improve the bearing load capacity and ensure that it has sufficient bending and torsional resistance.

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

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

[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, making it difficult to leak and unaffected by the rotation of the vane, resulting in stable bleed air pressure;

[0060] 2) The air intake is entirely confined inside the hollow shaft of the guide vane. Only a reasonable inner diameter of the shaft needs to be set to meet the air intake channel area requirements.

[0061] 3) Setting a large-diameter hollow shaft can effectively improve the bending and torsional resistance of the low-pressure turbine guide vane shaft, while avoiding excessive coupling with the cooling gas of the blade itself, thus increasing the accuracy of simulation and experimental verification.

[0062] Finally, it should be noted that the accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0063] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bleed air structure for a variable cycle engine with adjustable guide vanes and rotor axial force, characterized in that: It includes a high-pressure turbine rotor (1), a low-pressure turbine guide inner ring (2), an adjustable low-pressure turbine guide vane (3), a low-pressure turbine guide outer ring (4), a low-pressure turbine casing (5), and a low-pressure turbine rotor (7); The inner ring (2) of the low-pressure turbine guide is connected between the high-pressure turbine rotor (1) and the low-pressure turbine rotor (7), and the outer ring (4) of the low-pressure turbine guide is located on the outside of the adjustable low-pressure turbine guide vane (3). The high-pressure turbine disk cavity is located between the inner ring (2) of the low-pressure turbine guide, the high-pressure turbine rotor (1) and the low-pressure turbine rotor (7). The adjustable low-pressure turbine guide vane (3) is coaxially connected to the outer side of the inner ring (2) of the low-pressure turbine guide vane. A hollow rotating shaft (8) is provided inside the adjustable low-pressure turbine guide vane (3). The inner end of the hollow rotating shaft (8) is connected to the high-pressure and low-pressure turbine disk cavity, and the outer end is connected to the high-pressure gas generated by the compressor. The low-pressure turbine casing (5) is located on the outer side of the low-pressure turbine rotor (7). The outer end of the adjustable low-pressure turbine guide vane (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 disk cavity through the hollow rotating shaft (8) under closed conditions; The outer wall of the low-pressure turbine casing (5) is provided with an external air intake port (9), and the external air intake is connected to the high-pressure gas through a pipe; the side wall of the low-pressure turbine casing (5) near the adjustable low-pressure turbine guide vane (3) is provided with an internal air intake port (10), and a buffer cavity (11) is provided between the external air intake port (9) and the internal air intake port (10), and the internal air intake port (10) is connected to the air shaft; The adjustable low-pressure turbine guide vane (3) has a cylindrical connecting post (12) at its outer end. The connecting post (12) has a hollow structure inside. Multiple circular holes communicating with the external air intake (9) are opened on the side wall of the connecting post (12). The connecting post (12) is rotatably connected to the low-pressure turbine casing (5).

2. The variable cycle engine bleed air structure for adjusting guide vanes and rotor axial force as described in claim 1, characterized in that: An adjustable guide vane rocker arm (6) is provided between the adjustable low-pressure turbine guide vane (3) and the low-pressure turbine casing (5), which can drive the adjustable low-pressure turbine guide vane (3) to rotate; the adjustable guide vane rocker arm (6) is provided with a power source, which can drive the adjustable low-pressure turbine guide vane (3) to rotate.

3. The variable cycle engine bleed air structure for adjusting guide vanes and rotor axial force as described in claim 2, characterized in that: The top of the connecting column (12) is provided with an inner groove, and the adjustable guide vane rocker arm (6) is provided with a recessed block that is bolted to the inner groove.

4. The variable cycle engine bleed air structure for adjusting guide vanes and rotor axial force as described in claim 1, characterized in that: The adjustable low-pressure turbine guide vane (3) is a guide vane with a small aspect ratio.

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