基于光纤传感的液体浓度检测系统设计  

Design of Liquid Concentration Measurement System Based on Optical Fiber Sensing

作　　者：戴一帆[1] 张志伟[1,2] 

机构地区：[1]中北大学信息与通信工程学院,山西太原030051 [2]中北大学仪器与动态测试教育部重点实验室,山西太原030051

出　　处：《光学与光电技术》2016年第6期63-66,72,共5页Optics & Optoelectronic Technology

基　　金：山西省自然科学基金(2012011010-1)资助项目

摘　　要：根据洛伦兹电子理论、比尔定律以及朗伯定律,提出了溶液在一定浓度范围内与折射率线性关系的理论模型,并以光纤液体传感器为基础,引入"压差比"的概念,根据菲涅尔公式,从理论上得出溶液折射率与压差比的对应关系。通过偏振光调制法测量在不同浓度的Na2CO3溶液作用下的"压差比",从而实时、准确地测量液体浓度。采用光电探测器对偏振光信号进行探测,经光电变换后利用信号调理电路实现信号采集,模数转换后运用单片机实现信息的处理。实验结果表明,该方法的测量精度为5‰,与传统方法相比有较大提升。According to the theory of Lorentz electronic, Beer＇s law and Lambert＇s law, a theoreotical model of the linear re- lationship between the solution concentration and refractive index in a certain concentration range is put forward. The con- cept of ＂differential pressure＂ on the basis of optical fiber liquid sensor is introduced. According to the Fresnel formula, the relationship between refractive index and ＂pressure difference＂ in theory is derived. By measuring the ＂differential pressure＂ in Na2 COa solution in different refractive index according to polarization modulation method, a real-time and accurate meas- urement for solution concentration is done. The polarized light signal is detected by the photoelectric detector, and the signal acquisition is realized by the signal conditioning circuit after photoelectric conversion. The information processing is achieved by single chip microcomputer after A/D conversion. The experimental results show that the measurement accuracy of this method is 5%0, which has a great improvement compared with traditional methods.

关 键 词：菲涅尔公式 最小二乘法 光纤PBS 偏振光 溶液浓度 

分 类 号：TH744[机械工程—光学工程]