【作者】 佟庆彬；

【导师】 王海军；

【作者基本信息】 昆明理工大学 ， 水利水电工程， 2005， 硕士

【摘要】 光纤温度传感器因其具有防燃、防爆、不带电、抗电磁干扰、抗腐蚀、能在有害环境中安全运行等一系列优点,因而得到日益广泛的应用。而干涉型光纤温度传感器以全光纤、灵敏度高、能实现多路传感及传感量广等优点,在光纤温度传感器中占有十分重要的地位。本课题所研究的是用于混凝土坝温度测量的激光光纤干涉型传感器,是基于混凝土坝环境变化复杂,又要考虑多点测温、安全和远距离信号传输的要求而提出的。该传感器将激光干涉与光纤技术结合起来,能够实现坝体温度多点测量,具有极好的防电磁干扰、防爆和绝缘特性。 本文首先对满足高精度要求的传感器测头的结构进行了优化设计,该传感器测头以其独特的结构克服了传统的干涉型光纤温度传感器易受环境扰动影响的缺点。同时结合传感头的结构及测量原理建立了该测温系统的数学模型。 针对因采用保偏光纤而使输出信号比较微弱的特点,突破了传统的光纤干涉仪的光电检测方法,采用具有自扫描、高灵敏度、高分辨力、体积小、重量轻、机械抗震强度好和反映像素位置准确等优点的CCD器件拾取干涉条纹信号来实现光电转换。针对混凝土的施工对光纤的干扰,对光纤设计了一种新的结构,提高了测量精度、减小了测量误差;在研究混凝土施工中温度变化特性的基础上,提出了传感器在坝体测温时的标定方法。 针对于涉图的特点选取了合适的图像处理方法。针对坝体温度变化比较复杂的情况,编制的软件可对所获得的条纹图像数据进行自动条纹提取,以获得与温度变化量有关的条纹位移信息。所有处理过程都由微机自动完成,大大提高了测量的速度。 该系统经实验验证,达到了分辨力为0.01℃的要求,而且该温度测量系统具有自动、高精度、快速实时等优点,是实现温度自动化测量的一个新途径,在坝体温度测量及其它恶劣环境下温度的检测中有着非常诱人的应用前景。更多还原

【Abstract】 Fiber optic temperature sensor has been widely applied in many fields because of its advantages of security to fire, explosion, electricity, magnetic disturbance, erosion, and dangerous environments. The interferomentric fiber optic sensor has played an important role in temperature sensing field due to its fiber structure, high sensitivity, multiplex, and universal to lots of parameters. In this dissertation a new interferomentric fiber optic temperature sensor was presented. This sensor can be used in dam, where the environment is complexity. It is safe to use and can realize remote signal transmitting. Combined the laser interferometer with the fiber-optic technique it has the advantages of insulation, explosion protection and the anti-jamming ability to electromagnetism.At first, the structure of sensing head of the new sensor with a high precision was; optimized. By particular structure, this sensing head overcame the disadvantage of conventional interferomentric fiber optic sensor which is liable to environment disturbance. A mathematical model of the temperature sensing system was established based on the measurement principle and structure of sensing head.Next, a method that uses CCD to realize conversion from light to electricity was put forward in this dissertation. CCD has advantages of auto-scanning, high sensitivity, high resolution, small volume, lightweight, mechanical vibration resistance, and the accurate pix position. Using a CCD can break through the traditional sensing method of photoelectric and be suitable to the feebleness of interference fringes output from the highly birefringence fiber optic interferometer.According to the characteristic of interference image, a suitable interference fringe processing and auto-reading method was also described in this dissertation. Furthermore, software was made to automatic pick-up the character of the interference fringe in order to obtain the displacement of the fringe with the change of temperature. The software is aiming at the low temperature change rate under the dam. The whole processing is completed automatically by computer and the measurement velocity was greatly increased.At last, experiments have been done to verify the feasibility of the newinterferomentric fiber optic temperature sensor. The experimental results show that the resolution can reach 0.01°C, and the temperature measurement system has the advantages of high automation, high precision, and real time measurement. It is safe to say that this sensor is a new method to measure the temperature and has a bright future in the application of temperature measurement both in the dam and dangerous environment.更多还原