双圈同轴光纤传感器在润滑油介质中的输出特性

针对双圈同轴式光纤(TCCOF)位移传感器用于滑动轴承油膜厚度检测时,由于传播介质为润滑油,传感器输出特性会受到影响,本文根据折射定律分析了传播介质对光纤最大入射角的影响,考虑传播过程中的光损并利用光场的准高斯分布规律建立了润滑油环境下的传感器数学模型,同时通过仿真计算得到了传播介质不同时的传感器输出特性。在此基础上,搭建了相应的传感器标定实验平台进行验证。结果表明:空气中TCCOF传感器的灵敏度为0.691/mm,润滑油中TCCOF传感器的灵敏度为0.464/mm;TCCOF传感器在润滑油测量环境中可减小光功率不同对传感器特性的影响;TCCOF传感器灵敏度随着反射面曲率半径的增大而增大;由于具有对称结构,当反射面为圆柱面时,TCCOF传感器可减小探头周向安装角度对其输出特性的影响。因此,在利用TCCOF传感器进行油膜厚度检测时,必须在相应润滑油环境下及相应的反射面情况下进行传感器标定。

Output characteristics of sensor with two-circle coaxial optical fiber in lubricating oil medium

The output characteristics of sensor with two-circle coaxial optical fiber(TCCOF) are affected by the lubricating oil when the optical fiber sensor is adopted to measure the thickness of lubricating film. The effect of propagating medium on the maximum incidence angle of fiber is analyzed basing on the refraction law. The mathematical model of sensor in the lubricating oil environment is built taking into account the light loss and adopting the light intensity quasi-Gaussian distributing law. Meanwhile the output characteristics of sensor in the different propagating medium are gained by the simulating calculation of the model. Based on that the calibration experiment rig is built to verify the simulating output characteristics of sensor. The results indicate that the sensibility of TCCOF sensor are 0.691/mm in the air and 0.464/mm in the lubricating oil, respectively; the TCCOF sensor can eliminate the effect of changing optical power; the sensibility of TCCOF sensor increases with the increase of reflector curvature radius; the symmetrical structure of TCCOF sensor can decrease the effect of the different peripheral installing direction on the output of optical fiber sensor. Therefore, the TCCOF sensor must be calibrated in the corresponding lubricating oil and reflector environment.