Chen, Rongzhang
(2016)
Fiber-Optic Sensing for High-Temperature and Energy Applications.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Fiber-optic sensors act as important roles in many of today's industrial sectors. It provides vital information for a large number of applications such as process controls, fossil fuel and nuclear electrical power generation, transportation, and environment monitoring. Compared with their electronic counterparts, fiber-optic sensors truly stand out where extreme operation environments leave almost all the electronic sensors unusable. Derived from the superior properties of optical fibers such as high-temperature stability, immunity to electromagnetic interference and strong resistance to most chemicals, fiber-optic sensors can be engineered to deliver sensing performance under various adverse conditions. Recently numerous research efforts have been put to leverage those merits of optical fibers to achieve sensing capabilities under high-temperature environments (> 600 deg C).
In this thesis, five fiber-optic sensing schemes are demonstrated to explore and validate the potential of fiber-optic sensors for high-temperature and energy applications. The first scheme manifests itself as a high-temperature-stable distributed Bragg reflector (DBR) fiber laser which intrinsically is able to operate and measure ambient temperatures up to 750 deg C. The second scheme is based on self-heated high-attenuation fibers (HAFs). Thanks to HAFs and regenerated fiber Bragg gratings, a hot-wire flow meter with ambient temperature compensation was realized with all-optical fiber construction with maximum operational temperature at 800 deg C. In the third sensing scheme, the other kind of fiber grating laser, the distributed feedback (DFB) fiber laser as strain sensor is presented to monitor acoustic emissions for a lab-induced hydraulic fracturing process. The fourth scheme covers a 3D strain field imaging technique for hydraulic fracturing study, enabled by Rayleigh backscatter based optical frequency domain reflectometry (OFDR). In the fifth scheme, we are aiming at increasing the measurement accuracy of the OFDR system by reducing the system measurement noise level. Via cavity ring down method, the system noise is demonstrated to reduce by over 52%. All these technologies and devices offer reliable and flexible sensing solutions for high-temperature and energy industrials, which were not previously possible.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
20 September 2016 |
| Date Type: |
Publication |
| Defense Date: |
31 May 2016 |
| Approval Date: |
20 September 2016 |
| Submission Date: |
6 June 2016 |
| Access Restriction: |
3 year -- Restrict access to University of Pittsburgh for a period of 3 years. |
| Number of Pages: |
121 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Electrical and Computer Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
fiber optic, energy, high-temperature, distributed Bragg reflector, fiber laser, hot-wire anemometer, flow meter, distributed feedback, acoustic measurement, strain monitoring, hydraulic fracturing, Rayleigh scattering, distributed measurement, cavity ring down |
| Date Deposited: |
20 Sep 2016 18:34 |
| Last Modified: |
20 Sep 2019 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/23464 |
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