Abstract
A basic theoretical model of a distributed fiber optic system for detection and location of ammonia leaks is proposed and employed in computer simulations of principal system characteristics. The simulated system consists of an optical time-domain reflectometer (OTDR) interrogating a sensing optical fiber composed of silica core and polymer cladding doped with a reagent. The simulated processes include gas diffusion into the cladding, conversion of the reagent in presence of the analyte, time- and space-evolution of polarizability and absorption coefficient, propagation of the primary light pulse along the fiber, interaction of the pulse with the cladding and generation of a backscattered light signal registered afterwards by the OTDR detector. Juxtaposition of the simulated results and the demands laid on a real system results in several recommendations for further development and optimization of such sensing systems.
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Notes
- 1.
Sylgard (Dow Corning) is a commercial thermo-cross-linkable fiber cladding material based on polysiloxane formulation.
- 2.
Further on, we suppose that the radial co-ordinate is discretized into 100 intervals.
- 3.
Both fused silica and polysiloxane resin matrix contains extended siloxane network, though differing in its density and topology.
- 4.
Maximum of the absorption band is observed at \(\lambda _{\max } = 740{\textrm{ nm}}\).
- 5.
The ammonia accumulated within the cladding during the exposition is to be expected as the main source of possible discrepancies.
- 6.
However, sensing reversibility issues have to be carefully considered in this case.
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Acknowledgements
The research has been supported by the Ministry of Education, Youth and Sports of the Czech Republic, grants MSM6840770040 and MSM6840770021.
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Sýkora, O., Aubrecht, J., Klepáček, R., Kalvoda, L. (2011). Simulation of Distributed Detection of Ammonia Gas. In: Murín, J., Kompiš, V., Kutiš, V. (eds) Computational Modelling and Advanced Simulations. Computational Methods in Applied Sciences, vol 24. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-0317-9_7
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DOI: https://doi.org/10.1007/978-94-007-0317-9_7
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