| The continuous casting process has been widely used for most of the steel production in the world instead of conventional ingot casting/rolling. Traditionally, thermocouples are being widely used to monitor the mold temperature in the continuous casting which has the following drawbacks: large size, low spatial resolution, and single detection point. On the contrary, fiber optic sensors can be a promising solution to the continuous casting temperature monitoring owing to its advantage of compact size, high resolution, high-temperature survivability, etc..;In this thesis, we successfully developed extrinsic Fabry-Perot interferometer (EFPI) sensor for point temperature sensing, and optical frequency domain reflectometry (OFDR) system for distributed temperature sensing. We embedded the optical fiber and fiber optic sensors in the copper slide using electrodeposition for continuous high-temperature sensing. The sensing principle and the fabrication of EFPI sensors was discussed. To verify the best method for sensor coating, three different coating methods were applied to optical fiber sensors before embedding. We observed that the sensitivity of embedded EFPI sensor with wax coating has been surprisingly enhanced more than 30 times. An experiment designed monitoring the casting process of aluminum was conducted, showing fast time response of the embedded EFPI sensor. Also the basic working principle, the nonlinear sweep compensation method and the data processing procedure of OFDR system. A calibration experiment of OFDR system was also demonstrated in this thesis. The OFDR system can achieve 1 cm spatial resolution. |
