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

【摘要】：近年來(lái),分布式光纖測(cè)溫技術(shù)作為一種溫度測(cè)量手段得到了越來(lái)越多的運(yùn)用。相比于傳統(tǒng)的點(diǎn)式溫度傳感器,分布式光纖測(cè)溫技術(shù)以其抗電磁干擾、測(cè)量區(qū)域廣、穩(wěn)定性高和布線簡(jiǎn)單等特點(diǎn)受到了越來(lái)越多的重視。本文針對(duì)傳統(tǒng)溫度測(cè)量技術(shù)在遠(yuǎn)距離條件下的測(cè)溫受限問(wèn)題,設(shè)計(jì)了一種基于拉曼散射技術(shù)的分布式光纖測(cè)溫系統(tǒng),主要完成了以下幾個(gè)部分工作:1、研究拉曼散射技術(shù)的基礎(chǔ)理論,運(yùn)用了一套線性化的溫度解調(diào)公式。將拉曼散射公式進(jìn)行了泰勒展開(kāi),得出了拉曼散射信號(hào)中反斯托克斯光對(duì)溫度尤為敏感的理論公式;為了消除光源功率波動(dòng)和APD溫漂的影響,從而使用了斯托克斯信號(hào)解調(diào)反斯托克斯信號(hào)的方法,對(duì)該公式進(jìn)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(shè)計(jì)指標(biāo),完成了各個(gè)模塊的選型,搭建起實(shí)驗(yàn)室環(huán)境下的系統(tǒng)框架。光纖測(cè)溫系統(tǒng)中各個(gè)性能參數(shù)指標(biāo)不能單獨(dú)進(jìn)行分析,每個(gè)指標(biāo)都和模塊參數(shù)息息相關(guān),在研究了每個(gè)模塊參數(shù)對(duì)性能指標(biāo)影響的前提下,選擇了合適的模塊完成了整個(gè)系統(tǒng)的搭建。3、針對(duì)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(hào)處理技術(shù)的特點(diǎn),并提出了溫度解調(diào)補(bǔ)償算法。對(duì)于拉曼散射光非常微弱和難以采集的特點(diǎn),分析了幾種適合本系統(tǒng)去噪要求的微弱信號(hào)處理方法。同時(shí)使用一種衰減補(bǔ)償算法將整個(gè)光纖線上相同環(huán)境溫度的測(cè)溫點(diǎn)信號(hào)補(bǔ)償成一條水平曲線,用以解決拉曼散射光光強(qiáng)隨光纖距離變長(zhǎng)而減弱的問(wèn)題。4、完成了分布式光纖測(cè)溫系統(tǒng)軟件的設(shè)計(jì),并做了大量的性能相關(guān)實(shí)驗(yàn)。設(shè)計(jì)了數(shù)據(jù)采集與處理、溫度標(biāo)定與解調(diào)、溫度顯示與異常報(bào)警、數(shù)據(jù)保存等功能,在實(shí)驗(yàn)室環(huán)境下驗(yàn)證了各種性能指標(biāo)。實(shí)驗(yàn)結(jié)果證明,該系統(tǒng)在監(jiān)測(cè)3000m范圍時(shí)可以達(dá)到空間分辨率1.5m、測(cè)溫精度±2℃等指標(biāo)。
[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(hào)：1938808