Evaluation and Quantification of Optic Fiber Distributed Sensor Response in Air and Water Environments
Abstract
Dense and accurate experimental data are continuously sought after, especially for validation of computer codes. Codes can often produce dense calculations, and need equally dense experimental results for comparison. Optic fiber distributed sensors can provide the dense and accurate data desired. While this sensing technology is mature, the responses of these sensors need to be fully characterized for all experimental conditions. This study performed multiple analyses and experimentation with optic fiber distributed temperature sensors (DTS) in air and water environments. Multiple correction curves and calibration efforts were undertaken in order to quantify the response of DTS in these environments. Uncertainty was estimated for a common type of DTS installation, which can be applied to many experiments.
The cooling panel temperature profile in a 1:23 scale Water-cooled Reactor Cavity Cooling System (WRCCS) was measured with optic fiber DTS. The temperature profile of a riser (water) column was also investigated, during both steady and transient conditions. Fiber DTS were installed in the upper plenum of a 1:16 scale High-Temperature Gas-cooled Reactor (HTGR) facility. Sensor response and boiling detection analyses were performed in a simple boiling apparatus, and may lead to future refined efforts towards boiling detection with distributed optic fiber DTS. Optic fiber DTS are capable of producing high-resolution data in a multitude of applications. Since the fiber and coating used are inert to air and water, almost any environment within coating temperature limits can be investigated. The most severe limitations are from the fiber, its hygroscopic coating (polyimide), and the sensor installation efforts required. Isolation from mechanical strain must be achieved when taking Rayleigh backscatter DTS measurements. Fiber coating effects also must also be accounted for, especially for hygroscopic coatings such as polyimide.
Citation
Holler, David Michael (2019). Evaluation and Quantification of Optic Fiber Distributed Sensor Response in Air and Water Environments. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /186606.