MULTIPLEXED OPTICAL FIBER WEAR SENSOR

• US 20120201656A1
• Filed: 02/09/2011
• Published: 08/09/2012
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Energy Incorporated (Siemens AG)
• Inventors: Johnston, Robert T.
• Granted Patent: US 8,790,074 B2
• Time in Patent Office: Days
• US Class Current: 415/118
• CPC Class Codes: F01D 21/003 Arrangements for testing or measuring for measuring vibrations G01H
• CPC Class Codes: G01M 11/086 Details about the embedment of the optical fiber within the DUT
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

An optical fiber wear detector that includes one or more FBG sensors positioned within the fiber that are operable to reflect a defined wavelength of an optical input beam. The wear detector includes a light source for generating the optical input beam that propagates down the optical fiber and interacts with the FBG sensor. The wavelength of the optical beam that is reflected by the FBG sensor is detected, where loss of the reflected signal indicates that the fiber before the FBG sensor or the FBG sensor itself is damaged, which would most likely be an indication of wear on the component. The depth of wear can be determined by providing multiple FBG sensors in a single optical fiber and/or providing multiple optical fibers with one or more FBG sensors.

Claims

1. A wear sensor assembly for monitoring wear and other defects in a component, said sensor assembly comprising:

at least one light source generating an optical beam;

at least one optical fiber receiving the optical beam from the at least one light source, said optical fiber including a fiber core through which the optical beam propagates and a fiber Bragg grating formed in the core, said fiber Bragg grating being operable to reflect a predefined wavelength of the optical beam back along the optical fiber and allow other wavelengths in the optical beam to propagate through the fiber Bragg grating; and

a detector for detecting the reflected wavelength of the optical beam from the fiber Bragg grating, wherein detection or no detection of the reflected wavelength is indicative of the wear on the component.

2. The sensor assembly according to claim 1 wherein the at least one optical fiber is mounted to the component in a meandering orientation and the at least one fiber Bragg grating is a plurality of fiber Bragg gratings positioned within the optical fiber and spaced apart so that the fiber Bragg gratings are in line with each other.

3. The sensor assembly according to claim 2 wherein each fiber Bragg grating reflects a different optical wavelength so that detection or no detection of the reflected wavelength of the optical beam indicates a depth of the wear in the component.

4. The sensor assembly according to claim 1 wherein the at least one optical fiber is a plurality of optical fibers mounted to the component where each optical fiber includes a fiber Bragg grating.

5. The sensor assembly according to claim 4 wherein each fiber Bragg grating in each optical fiber reflects the same wavelength of the optical beam.

6. The sensor assembly according to claim 5 wherein the plurality of optical fibers are mounted to the component so that the fiber Bragg gratings in the plurality of optical fibers are oriented in line with each other so that detection or no detection of the reflected wavelength of the optical beam indicates a depth of the wear in the component.

7. The sensor assembly according to claim 1 wherein the at least one optical fiber is a plurality of optical fibers where each optical fiber includes a plurality of spaced apart fiber Bragg gratings.

8. The sensor assembly according to claim 7 wherein each fiber Bragg grating in each optical fiber reflects a different wavelength of the optical beam, and wherein the fiber Bragg gratings in different optical fibers are in line with each other.

9. The sensor assembly according to claim 1 wherein the at least one optical fiber is a single optical fiber including a plurality of spaced apart fiber Bragg gratings where each fiber Bragg grating reflects a different wavelength of the optical beam, and wherein opposite ends of the optical fiber are coupled to different channels that provide different input optical beams.

10. The sensor assembly according to claim 1 wherein the component is part of a turbine engine.

11. A wear sensor for monitoring wear and other defects in a component, said sensor comprising at least one optical fiber receiving an optical beam, said optical fiber including a fiber core through which the optical beam propagates and a plurality of fiber Bragg gratings formed in the core and being spaced apart from each other, each fiber Bragg grating being operable to reflect a predefined wavelength of the optical beam back along the optical fiber and allow other wavelengths in the optical beam to propagate through the fiber Bragg grating, where loss of the reflected wavelength indicates wear on the component.

12. The sensor according to claim 11 wherein the at least one optical fiber is mounted to the component in a meandering orientation and the plurality of fiber Bragg gratings are positioned within the optical fiber and spaced apart so that the fiber Bragg gratings are in line with each other.

13. The sensor according to claim 12 wherein each fiber Bragg grating reflects a different optical wavelength to indicate a depth of the wear in the component.

14. The sensor according to claim 11 wherein the at least one optical fiber is a plurality of optical fibers where each optical fiber includes a plurality of spaced apart fiber Bragg gratings.

15. The sensor according to claim 11 wherein the at least one optical fiber is a single optical fiber, and wherein opposite ends of the optical fiber are coupled to different channels that provide different input optical beams.

16. A gas turbine engine comprising:

a shaft rotatably provided along a center line of the engine;

a compressor section responsive to a working fluid and being operable to compress the working fluid to produce a compressed working fluid;

a combustion section in fluid communication with the compressor section that receives the compressed working fluid, said combustion section mixing the compressed working fluid with a fuel and combusting the compressed fluid and fuel mixture to produce a hot working fluid;

a turbine section in fluid communication with the combustion section, said turbine section expanding the hot working fluid to produce mechanical power through rotation of the shaft; and

at least one wear sensor operatively coupled to a component in the engine, said at least one wear sensor including at least one optical fiber receiving an optical beam, said at least one optical fiber including a fiber core through which the optical beam propagates and at least one fiber Bragg grating formed in the core, said at least one fiber Bragg grating being operable to reflect a predefined wavelength of the optical beam back along the optical fiber and allow other wavelengths in the optical beam to propagate through the fiber Bragg grating, where the reflected optical wavelength can be analyzed to determine wear on the component.

17. The engine according to claim 16 wherein the component is a vane mounting component in the turbine section.

18. The engine according to claim 16 wherein the at least one optical fiber is mounted to the component in a meandering orientation and the at least one fiber Bragg grating is a plurality of fiber Bragg gratings positioned within the optical fiber and spaced apart so that the fiber Bragg gratings are in line with each other.

19. The engine according to claim 18 wherein each fiber Bragg grating reflects a different optical wavelength so that detection or no detection of the reflected wavelength of the optical beam indicates a depth of the wear in the component.

20. The engine according to claim 16 wherein the at least one optical fiber is a plurality of optical fibers mounted to the component where each optical fiber includes a fiber Bragg grating.