Theoretical design and analysis of a sensing system for high pressure and temperature measurement in subsea underwater applications.

Amos, Solomon; Prabhu, Radhakrishna; Njuguna, James

Abstract

The theoretical design and analysis of a metal coated hybrid sensing system of Fibre Bragg Grating (FBG) and Extrinsic Fabry-Perot Interferometer (EFPI) cavity for high pressure high temperature (HPHT) measurement in subsea underwater applications is reported. The FBG and EFPI are used to measure temperature and pressure respectively. An opto-mechanical model that assesses the measurement of HPHT for subsea underwater applications with hybrid sensing system was developed. In this model, coating of the sensor with metallic materials is studied. The model combines both optical and structural analyses for developing an optimal sensor system design. The optical analysis is carried out to obtain the spectral response of the sensor while the structural analysis is used to obtain the change in optical properties of the sensor due to photo-elastic effect. Analytical results showed that the temperature sensitivity of the hybrid sensor with double layer metal coated FBG increased to 23.89 pm/ {deg}C when compared with single metal coated FBG of 13.95 pm/ {deg}C from previous study and the associated pressure range measured up to 5000 Psi. Furthermore, the proposed sensor design has shown good linearity. While the single coated FBG sensor shows little sensitivity, the sensitivity increases with thickness for double metal coating.

Citation

AMOS, S., PRABHU, R. and NJUGUNA, J. 2017. Theoretical design and analysis of a sensing system for high pressure and temperature measurement in subsea underwater applications. In Proceedings of OCEANS 2017, 19-22 June 2017, Aberdeen, UK. New York: IEEE [online], article number 8085023, pages 2680-2686. Available from: https://doi.org/10.1109/OCEANSE.2017.8085023

• Conference Name: OCEANS 2017 (Aberdeen)
• Conference Location: Aberdeen, UK
• Start Date: Jun 19, 2017
• End Date: Jun 22, 2017
• Acceptance Date: Jun 19, 2017
• Online Publication Date: Jun 19, 2017
• Publication Date: Oct 26, 2017
• Deposit Date: Jan 23, 2018
• Publicly Available Date: Jan 23, 2018
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Article Number: 8085023
• Pages: 2680-2686
• ISBN: 9781538621110
• DOI: https://doi.org/10.1109/OCEANSE.2017.8085023
• Keywords: Fibre Bragg grating; Extrinsic Fabry Perot Interferometer; Sensitivity; High pressure high temperature
• Public URL: http://hdl.handle.net/10059/2681