基于激光诱导水拉曼抑制法的油膜厚度测量方法研究

为了实现水体表面油膜厚度的快速测量分析，以266 nm的激光作为探测系统的激发光源，基于激光诱导水拉曼散射光谱检测技术，通过获取不同种类不同厚度油膜存在下水拉曼光谱信息，建立油膜厚度反演模型。采用高斯函数拟合法校正了荧光光谱对拉曼光谱的干扰。然后根据水拉曼抑制法结合非线性最小二乘优化算法，建立油膜厚度反演模型。结果表明：对92#汽油、0#柴油、美孚机油20w-40、壳牌润滑油10w-40、采埃孚变速箱油AG6和原油油膜能探测到的油膜厚度范围为0.19~379.22 μm。采用水拉曼光谱-油膜厚度反演模型预测油膜厚度的平均相对误差在8.14%~15.81%之间。该方法能实现实验室条件下对微米级油膜的测量。

Research on Measuring Oil Film Thickness Based on Laser-Induced Water Raman Suppression Method

In this work, using a 266 nm laser as the excitation light source of the detection system, the water Raman spectra under the oil film of different thicknesses were obtained based on the laser-induced water Raman spectroscopy technology. The Gaussian function fitting method was used to correct the interference of the fluorescence spectrum on the Raman spectrum. And then, the oil film thickness inversion model could be established according to the water Raman suppression method combined with the nonlinear least square optimization algorithm. The results show that the six oils’ detectable oil film thickness range (92# gasoline, 0# diesel, Mobil oil 20w-40, Shell Helix10w-40, Lifeguard Fluid AG6 and crude oil) is from 0.19 to 379.22 μm. The average relative error of oil film thickness prediction ranges from 8.14% to 15.81% according to the water Raman spectrum-oil film thickness inversion model. This method can realize the measurement of micron-level oil film under laboratory conditions.