Low-pressure shaft failure device

Abstract

A low-pressure shaft failure device is used for enabling a low-pressure shaft to fail at a specified rotating speed in an over-rotation protection test of a turbofan engine. The low-pressure shaft failure device comprises a low-pressure shaft test piece, a clutch device, a rotating speed sensor and a clutch control device. The low-pressure shaft test piece comprises a first shaft section and a second shaft section; the clutch device is arranged on the low-pressure shaft test piece and is used for connecting or disconnecting the first shaft section and the second shaft section; the rotating speed sensor is used for measuring the rotating speed of the low-pressure shaft test piece; the clutch control device controls the clutch device to disconnect the first shaft section and the second shaft section when the low-pressure shaft test piece reaches a set rotating speed.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine tests, and particularly relates to a low-pressure shaft failure device for a high-pressure turbine over-speed protection test of a turbofan engine. Background Art

[0002] According to the requirements of the AC 33.27 airworthiness regulations for turbines, compressors, fans, and turbocharger rotors, an aero-engine needs to have an over-speed protection function. To complete the verification of the over-speed protection system of an aero-engine, it is necessary to demonstrate that the low-pressure rotor blades can prevent the low-pressure turbine from exceeding the verified speed limit through the way of rubbing between the rotating and stationary parts in the case of the failure of the low-pressure shaft. Making the low-pressure shaft of an aero-engine fail when reaching the specified speed is a necessary condition for carrying out this compliance verification work.

[0003] Currently, in the existing compliance verification work of the over-speed protection system of an aero-engine, there is still a lack of measures to make the low-pressure shaft fail at the specified speed. Therefore, it is urgent to propose a device that can make the low-pressure shaft fail at the specified speed. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-pressure shaft failure device for making the low-pressure shaft fail at a specified speed in a high-pressure turbine over-speed protection test of a turbofan engine.

[0005] According to an embodiment of the present invention, the low-pressure shaft failure device includes a low-pressure shaft test piece, a clutch device, a speed sensor, and a clutch control device; the low-pressure shaft test piece includes a first shaft section and a second shaft section; the clutch device is arranged on the low-pressure shaft test piece for connecting or disconnecting the first shaft section and the second shaft section; the speed sensor is used for measuring the speed of the low-pressure shaft test piece; the clutch control device controls the clutch device to disconnect the first shaft section and the second shaft section when the low-pressure shaft test piece reaches the set speed.

[0006] In one or more embodiments, the clutch device includes a driving mechanism and a driven mechanism, the driving mechanism is arranged on one of the first shaft section and the second shaft section, the driven mechanism is arranged on the other of the first shaft section and the second shaft section, the driving mechanism is connected to the driven mechanism, and the clutch control device controls the driving mechanism to disconnect the driven mechanism when the low-pressure shaft test piece reaches the set speed.

[0007] In one or more embodiments, the clutch device is an electromagnetic clutch device.

[0008] In one or more embodiments, the speed sensor is arranged on an intermediate casing.

[0009] In one or more embodiments, the first shaft section is located axially forward of the second shaft section. The first shaft section is supported by an intermediate casing, and the second shaft section is supported by a low-pressure turbine casing.

[0010] In one or more embodiments, the clutch device includes a driving mechanism and a driven mechanism. The driving mechanism is disposed on the second shaft section, the driven mechanism is disposed on the first shaft section, and the clutch control device is disposed on the second shaft section. The driving mechanism is connected to the driven mechanism, and the clutch control device controls the driving mechanism to disconnect the driven mechanism when the low-pressure shaft test piece reaches a set speed.

[0011] In one or more embodiments, the clutch control device is connected to the speed sensor through a signal transmission line to obtain the speed of the low-pressure shaft test piece.

[0012] In one or more embodiments, the clutch control device is connected to the clutch device through a signal transmission line to control the clutch device to disconnect the first shaft section and the second shaft section.

[0013] The embodiments of the present invention at least have the following beneficial effects:

[0014] When the low-pressure shaft test piece reaches the set speed, the clutch control device controls the clutch device to disconnect the first shaft section and the second shaft section, simulating the situation where the real low-pressure shaft fails at the specified speed, facilitating the verification of the over-speed protection system of the aero-engine, and supporting the airworthiness certification of the aero-engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other features, properties, and advantages of the present invention will become more apparent from the following description in conjunction with the drawings and embodiments, where:

[0016] Figure 1 is a schematic diagram of the low-pressure shaft failure device connecting the first shaft section and the second shaft section;

[0017] Figure 2 is a schematic diagram of the low-pressure shaft failure device disconnecting the first shaft section and the second shaft section;

[0018] Reference Numerals:

[0019] 1 - Fan;

[0020] 2 - Low-pressure compressor;

[0021] 3 - High-pressure compressor;

[0022] 4 - Combustion chamber;

[0023] 5 - High-pressure turbine;

[0024] 6 - Low-pressure turbine;

[0025] 7 - Intermediate casing;

[0026] 8 - Inter - stage casing;

[0027] 9 - Casing behind turbine;

[0028] 10 - No.1 bearing;

[0029] 11 - No.2 bearing;

[0030] 12 - No.5 bearing;

[0031] 13 - Low - pressure shaft test piece;

[0032] 1301 - First shaft section;

[0033] 1302 - Second shaft section;

[0034] 14 - Fan shaft;

[0035] 15 - High - pressure shaft;

[0036] 16 - Rotation speed sensor;

[0037] 17 - Clutch device;

[0038] 1701 - Driven mechanism;

[0039] 1702 - Driving mechanism;

[0040] 18 - Clutch control device;

[0041] 19 - First signal transmission line;

[0042] 20 - Second signal transmission line. Detailed implementation mode

[0043] Now, reference will be made in detail to the embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it will be obvious to those skilled in the art that various modifications and changes can be made to the present invention without departing from the scope or spirit of the present invention. For example, features shown or described as part of one embodiment can be used with another embodiment to yield yet another embodiment. Accordingly, the present invention is intended to cover these modifications and changes that fall within the scope of the appended claims and their equivalents.

[0044] It should be noted that these and subsequent other drawings are only examples, and they are not drawn under the condition of equal proportion, and should not be used to limit the actual scope of protection required by the present invention.

[0045] The terms "first", "second", etc. may be used interchangeably to distinguish one feature from another, and are not intended to indicate that the respective features must be located in the positions shown in each embodiment.

[0046] Figure 1 and Figure 2 The low-pressure shaft failure device applied to a high-bypass ratio turbofan engine with a dual-rotor, direct-drive, and separate exhaust for the inner and outer ducts is shown, and the low-pressure shaft failure device is described by taking this as an example. It should be understood that the low-pressure shaft failure device can also be applied to other types of turbofan engines.

[0047] As Figure 1 shown, the turbofan engine may mainly consist of a fan 1, a low-pressure compressor 2, a high-pressure compressor 3, a combustion chamber 4, a high-pressure turbine 5, and a low-pressure turbine 6. The fan 1, the low-pressure compressor 2, and the low-pressure turbine 6 constitute the low-pressure rotor. The fan 1, the low-pressure compressor 2, and the low-pressure turbine 6 are connected by a low-pressure shaft test piece 13. The low-pressure turbine 6 drives the fan 1 and the low-pressure compressor 2 to rotate. The fan shaft 14 can be connected to the front end of the low-pressure shaft test piece 13, and the low-pressure turbine 6 can be connected to the rear end of the low-pressure shaft test piece 13. The high-pressure compressor 3 and the high-pressure turbine 5 constitute the high-pressure rotor. The high-pressure compressor 3 and the high-pressure turbine 5 are connected by a high-pressure shaft 15. The high-pressure turbine 5 drives the high-pressure compressor 3 to rotate. The high-pressure shaft 15 can be supported by an intermediate casing 7 and an inter-stage casing 8.

[0048] As Figure 1 shown, the low-pressure shaft failure device includes a low-pressure shaft test piece 13. The low-pressure shaft test piece 13 includes a first shaft section 1301 and a second shaft section 1302. The first shaft section 1301 and the second shaft section 1302 are axially connected to form the low-pressure shaft test piece 13. The first shaft section 1301 can be located on the axial front side of the second shaft section 1302. The rear end of the first shaft section 1301 is connected to the front end of the second shaft section 1302 to form the low-pressure shaft test piece 13. The low-pressure shaft test piece 13 can be provided with three support points: a first bearing 10, a second bearing 11, and a fifth bearing 12. The first bearing 10 can also be called the 1# bearing. The second bearing 11 can also be called the 2# bearing. The fifth bearing 12 can also be called the 5# bearing. The first shaft section 1301 can be supported by the intermediate casing 7. The first shaft section 1301 can be supported by the intermediate casing 7 through the first bearing 10 and the second bearing 11. The first bearing 10 can be a roller bearing, mainly used for transmitting radial force. The second bearing 11 can be a ball bearing, used for transmitting both radial force and axial force. The second shaft section 1302 can be supported by a turbine rear casing 9. The second shaft section 1302 can be supported by the turbine rear casing 9 through the fifth bearing 12. The fifth bearing 12 can be a roller bearing, mainly used for transmitting radial force.

[0049] As Figure 1As shown, the low-pressure shaft failure device further includes a clutch device 17. The clutch device 17 is arranged on the low-pressure shaft test piece 13 and is used to connect or disconnect the first shaft section 1301 and the second shaft section 1302. When the first shaft section 1301 and the second shaft section 1302 are connected, they rotate in the same direction and at the same speed, allowing the low-pressure shaft test piece 13 to transmit power and simulate the normal working state of a real low-pressure shaft. For example, Figure 2 as shown, when the first shaft section 1301 and the second shaft section 1302 are disconnected, the physical connection between the first shaft section 1301 and the second shaft section 1302 is completely disconnected, and the first shaft section 1301 and the second shaft section 1302 are separated, simulating the situation of a real low-pressure shaft failure. The clutch device 17 may include a driving mechanism 1702 and a driven mechanism 1701. The driving mechanism 1702 is arranged on one of the first shaft section 1301 and the second shaft section 1302, and the driven mechanism 1701 is arranged on the other of the first shaft section 1301 and the second shaft section 1302. The driving mechanism 1702 can be connected to the driven mechanism 1701, so that the first shaft section 1301 and the second shaft section 1302 are connected. The driving mechanism 1702 can also disconnect the driven mechanism 1701, so that the first shaft section 1301 and the second shaft section 1302 are disconnected.

[0050] For example, Figure 1 as shown, the low-pressure shaft failure device further includes a speed sensor 16. The speed sensor 16 is used to measure the speed of the low-pressure shaft test piece 13. The speed sensor 16 can be arranged on the intermediate casing 7. The speed sensor 16 can be a variable magnetic flux type sensor designed according to the principle of electromagnetic induction. When the low-pressure shaft test piece 13 rotates, it will drive the gear of the speed sensor 16 to rotate. Each time a tooth passes, the magnetic circuit reluctance changes once, and the magnetic flux also changes once. The frequency of the induced electromotive force generated in the coil of the speed sensor 16 also changes once. The change frequency of the induced electromotive force generated in the coil is the product of the number of teeth and the speed.

[0051] For example, Figure 1As shown in the figure, the low-pressure shaft failure device further includes a clutch control device 18. The clutch control device 18 controls the clutch device 17 to disconnect the first shaft section 1301 and the second shaft section 1302 when the low-pressure shaft test piece 13 reaches the set speed. When verifying the over-speed protection system of the aero-engine, the initial state of the clutch device 17 is to connect the first shaft section 1301 and the second shaft section 1302, simulating the normal working state of the real low-pressure shaft. The driving mechanism 1702 can be connected to the driven mechanism 1701, thereby connecting the first shaft section 1301 and the second shaft section 1302. When the low-pressure shaft test piece 13 reaches the set speed, the clutch control device 18 controls the clutch device 17 to disconnect the first shaft section 1301 and the second shaft section 1302, simulating the situation where the real low-pressure shaft fails at the specified speed, facilitating the verification of the over-speed protection system of the aero-engine and supporting the airworthiness certification of the aero-engine. The clutch control device 18 can control the driving mechanism 1702 to disconnect the driven mechanism 1701 to disconnect the first shaft section 1301 and the second shaft section 1302.

[0052] As Figure 1 shown, the clutch control device 17 can be connected to the speed sensor 16 through the first signal transmission line 19, and the input end of the clutch control device 17 obtains the real-time speed of the low-pressure shaft test piece 13 from the speed sensor 16 through the first signal transmission line 19. As Figure 1 shown, the clutch control device 17 can be connected to the clutch device 17 through the second signal transmission line 20, and the output end of the clutch control device 17 sends a control signal to the clutch device 17 through the second signal transmission line 20 to control the clutch device 17 to disconnect the first shaft section 1301 and the second shaft section 1302.

[0053] As Figure 1 shown, the clutch control device 17 can be arranged on the low-pressure shaft test piece 13. The clutch control device 17 can be connected to the driving mechanism 1702 through the second signal transmission line 20, and the output end of the clutch control device 17 sends a control signal to the driving mechanism 1702 through the second signal transmission line 20 to control the driving mechanism 1702 to disconnect the driven mechanism 1701. The clutch control device 17 and the driving mechanism 1702 can be arranged on the same shaft section. The driving mechanism 1702 can be arranged on the second shaft section 1302 and can be arranged at the front end of the second shaft section 1302, and the driven mechanism 1701 can be arranged on the first shaft section 1301 and can be arranged at the rear end of the first shaft section 1301, and the clutch control device 17 can be arranged on the second shaft section 1302.

[0054] As Figure 1As shown, the clutch device 17 can be an electromagnetic clutch device. The electromagnetic clutch device applies the principle of electromagnetic induction and the frictional force between the inner and outer friction plates. It is an automatically actuated electromagnetic mechanical connector, which has the advantages of simple structure, small volume, fast action, small control energy, rapid and smooth braking, and can connect and disconnect the first shaft section 1301 and the second shaft section 1302 without stopping rotation. When verifying the over-speed protection system of an aero-engine, the initial state of the electromagnetic clutch device is powered on, the driving mechanism 1702 engages the driven mechanism 1701, connecting the first shaft section 1301 and the second shaft section 1302 to simulate the normal working state of the real low-pressure shaft. When the low-pressure shaft test piece 13 reaches the set speed, the clutch control device 18 controls the coil of the electromagnetic clutch device to be powered off, the driving mechanism 1702 disconnects the driven mechanism 1701, and disconnects the first shaft section 1301 and the second shaft section 1302 to simulate the situation where the real low-pressure shaft fails at the specified speed.

[0055] Although the present invention is disclosed as above with embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention.

Claims

1. A low-pressure shaft failure device for over-speed protection tests of turbofan engines, characterized in that it includes: A low-pressure shaft test piece, including a first shaft section and a second shaft section; A clutch device, arranged on the low-pressure shaft test piece, for connecting or disconnecting the first shaft section and the second shaft section; A speed sensor, for measuring the speed of the low-pressure shaft test piece; and A clutch control device, which controls the clutch device to disconnect the first shaft section and the second shaft section when the low-pressure shaft test piece reaches a set speed.

2. The low-pressure shaft failure device according to claim 1, characterized in that: The clutch device includes a driving mechanism and a driven mechanism. The driving mechanism is arranged on one of the first shaft section and the second shaft section, and the driven mechanism is arranged on the other of the first shaft section and the second shaft section. The driving mechanism connects the driven mechanism, and the clutch control device controls the driving mechanism to disconnect the driven mechanism when the low-pressure shaft test piece reaches a set speed.

3. The low-pressure shaft failure device according to claim 1 or 2, characterized in that: The clutch device is an electromagnetic clutch device.

4. The low-pressure shaft failure device according to claim 1, characterized in that: The speed sensor is arranged on the intermediate casing.

5. The low-pressure shaft failure device according to claim 1, characterized in that: The first shaft section is located axially in front of the second shaft section. The first shaft section is supported by the intermediate casing, and the second shaft section is supported by the turbine rear casing.

6. The low-pressure shaft failure device according to claim 5, characterized in that: The clutch device includes a driving mechanism and a driven mechanism. The driving mechanism is arranged on the second shaft section, and the driven mechanism is arranged on the first shaft section. The clutch control device is arranged on the second shaft section. The driving mechanism connects the driven mechanism, and the clutch control device controls the driving mechanism to disconnect the driven mechanism when the low-pressure shaft test piece reaches a set speed.

7. The low-pressure shaft failure device according to claim 1, characterized in that: The clutch control device is connected to the speed sensor through a signal transmission line to obtain the speed of the low-pressure shaft test piece.

8. The low-pressure shaft failure device according to claim 1, characterized in that: The clutch control device is connected to the clutch device through a signal transmission line to control the clutch device to disconnect the first shaft section and the second shaft section.

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