本文選題：分布式光纖 + 拉曼散射�。� 參考：《大連海事大學》2017年碩士論文

【摘要】：近年來,分布式光纖測溫技術(shù)作為一種溫度測量手段得到了越來越多的運用。相比于傳統(tǒng)的點式溫度傳感器,分布式光纖測溫技術(shù)以其抗電磁干擾、測量區(qū)域廣、穩(wěn)定性高和布線簡單等特點受到了越來越多的重視。本文針對傳統(tǒng)溫度測量技術(shù)在遠距離條件下的測溫受限問題,設計了一種基于拉曼散射技術(shù)的分布式光纖測溫系統(tǒng),主要完成了以下幾個部分工作:1、研究拉曼散射技術(shù)的基礎理論,運用了一套線性化的溫度解調(diào)公式。將拉曼散射公式進行了泰勒展開,得出了拉曼散射信號中反斯托克斯光對溫度尤為敏感的理論公式;為了消除光源功率波動和APD溫漂的影響,從而使用了斯托克斯信號解調(diào)反斯托克斯信號的方法,對該公式進行了分析和線性化處理,最后使用線性化公式解調(diào)溫度。2、根據(jù)系統(tǒng)的設計指標,完成了各個模塊的選型,搭建起實驗室環(huán)境下的系統(tǒng)框架。光纖測溫系統(tǒng)中各個性能參數(shù)指標不能單獨進行分析,每個指標都和模塊參數(shù)息息相關(guān),在研究了每個模塊參數(shù)對性能指標影響的前提下,選擇了合適的模塊完成了整個系統(tǒng)的搭建。3、針對采集到的拉曼散射光及其系統(tǒng)噪聲類別,分析了各種信號處理技術(shù)的特點,并提出了溫度解調(diào)補償算法。對于拉曼散射光非常微弱和難以采集的特點,分析了幾種適合本系統(tǒng)去噪要求的微弱信號處理方法。同時使用一種衰減補償算法將整個光纖線上相同環(huán)境溫度的測溫點信號補償成一條水平曲線,用以解決拉曼散射光光強隨光纖距離變長而減弱的問題。4、完成了分布式光纖測溫系統(tǒng)軟件的設計,并做了大量的性能相關(guān)實驗。設計了數(shù)據(jù)采集與處理、溫度標定與解調(diào)、溫度顯示與異常報警、數(shù)據(jù)保存等功能,在實驗室環(huán)境下驗證了各種性能指標。實驗結(jié)果證明,該系統(tǒng)在監(jiān)測3000m范圍時可以達到空間分辨率1.5m、測溫精度±2℃等指標。
[Abstract]:In recent years, distributed optical fiber temperature measurement technology as a means of temperature measurement has been used more and more. Compared with the traditional point temperature sensor, distributed optical fiber temperature measurement technology has attracted more and more attention for its characteristics of anti-electromagnetic interference, wide measurement area, high stability and simple wiring. In this paper, a distributed optical fiber temperature measurement system based on Raman scattering is designed to solve the problem of limited temperature measurement of traditional temperature measurement technology under remote conditions. The following parts have been completed: 1. The basic theory of Raman scattering has been studied and a set of linearized temperature demodulation formula has been applied. The Taylor expansion of Raman scattering formula is carried out, and the theoretical formula of anti-Stokes light sensitivity to temperature in Raman scattering signal is obtained, in order to eliminate the influence of light source power fluctuation and APD temperature drift. The method of demodulating anti-Stokes signal with Stokes signal is used, and the formula is analyzed and linearized. Finally, the temperature of demodulation by linearization formula is used to demodulate the temperature. According to the design index of the system, the selection of each module is completed. Set up the system frame in the laboratory environment. Each performance parameter index in fiber optic temperature measurement system can not be analyzed separately, and each index is closely related to module parameter. Under the premise of studying the influence of each module parameter on performance index, The appropriate module is selected to complete the whole system. The characteristics of various signal processing techniques are analyzed according to the Raman scattering light collected and the noise types of the system. A temperature demodulation compensation algorithm is proposed. For the characteristics of very weak Raman scattering light and difficult to be collected, several weak signal processing methods are analyzed which are suitable for the de-noising requirement of the system. At the same time, a attenuation compensation algorithm is used to compensate the signal of the same ambient temperature point in the whole fiber line into a horizontal curve. In order to solve the problem that the intensity of Raman scattering light decreases with the increase of fiber distance, the software of distributed optical fiber temperature measurement system is designed, and a large number of performance experiments are done. The functions of data acquisition and processing, temperature calibration and demodulation, temperature display and abnormal alarm, and data preservation are designed. The experimental results show that the system can achieve the spatial resolution of 1.5m and the accuracy of temperature measurement 鹵2 鈩，

本文編號：1938808