A Study On Sensing Technology Temperature And Strain Based On Distributed Optical Fiber Brillouin Scattering

Distributed fiber optical sensing can meet the requirements of long-distance and high anti-electromagnetic interference, be easy to obtain the parameter information of monitoring body completely, which can be widely used in multi-point temperature and strain measurements. Based on the principle of Brillouin backscatter sensor technology,optical fiber Brillouin scattering sensing can realize the real continuous high precision and high space resolution distributed monitoring.In this paper,firstly, the history background and development situation of the optical fiber sensors are outlined, the development condition and trend of distributed fiber sensor at home and abroad are summarized, the distributed fiber sensors technology basing on nonlinear scatters is introduced, the strategy and advantages of the distributed optical fiber Brillouin sensors are pointed out, the relations between the Brillouin frequency shift and temperature strain are theoretically analyzed, it has related experimental on temperature strain, result show: in fiber length of1798m, the spatial resolution is1m, the temperature sensitivity is1.0012MHz/℃; in fiber length of200m, the spatial resolution is1m, the axial tension0.03MHz/N.Secondly, the contrast experiments of fiber on oil and gas pipelines in different laying way is implemented, its result show:in fiber length of323m, the spatial resolution is1m, the axial tension is0.8MHz/N in the point contact, the axial tension is0.7MHz/N in the surface contact, the axial tension is0.6MHz/N in the surround type. The point or surface contact applies to the strain of low sensitivity and the surround-suitable applies to the strain of high sensitivity. Finally, using Labview and Matlab mix programming,a leakage detection and pre-warning system based on distributed optical fiber for a long-distance oil and gas pipeline has been accomplished and displayed on the PC.