Distributed Optical Fiber Temperature Measurement System And Its Application To Shaft Freeze

Distributed optical fiber temperature measurement system may monitor the temperature of many points on an optical fiber at the same time, and may carry on the space orientation using the Optical Time Domain Reflection technology to the temperature field. Under many specific environment situations, the request simultaneously monitor the massive positions even is the temperature quantity which changes continuously along the long distance position, the traditional spot type temperature sensor is unable to realize the sensing survey effectively.Based on the analysis and research in Raman Distributed optical fiber temperature sensor measuring principle, take main technology index of the system and the signal luminous power's size as a benchmark, has completed the Raman Distributed Optical Fiber temperature measurement system's structural design, developed a set of experimental system successfully on this basis. This dissertation has completed smoothly temperature monitoring experimental duties which how to monitor the freezing temperature field of the frozen wall.In this topic, put forward a new demodulation method using Rayleigh scattering signal to demodulate anti-stokes scattering, derived the formula demodulating temperature and discussed a new demodulation method to improve system performance. After briefly introducing the working processor of the system, the paper described the functional modules of the distributed optical fiber temperature measurement system in detail: the light source module, optical wavelength division multiplexing module, optical fiber sensing probe, optoelectronic receiver amplification module, signal acquisition and processing modules and system software. Discussed in detail the system operating wavelength and select Media Converter parts, high-speed data acquisition card of the performance of the entire system performance, system calibration, the system parameters and the characteristics of the factors affecting these parameters; introduce the way how to use the optical fiber temperature measurement system and the flow of system software.Given a detailed analysis about the system spatial resolution, signal to noise ratio and stability, and proposed the implementation methods to improve the system spatial resolution and system stability.This system compared with the existing single-bus temperature sensor system for temperature measurement while using in the monitoring the well's frozen-wall temperature field process, finally indicated that this system has had the substitution existing well's frozen-wall temperature measurement system's practical significance. Its good economy, stability, reliability, real-time and temperature distribution, so that it's possible to replace the existing wall freezing temperature measurement system.It has an important practical significance to improve the freezing method of drilling technology, to speed up construction process of freezing shaft-sinking method.