Voigt线型两翼拟合非均匀流场吸光度的方法研究

发布时间：2018-12-08 07:42

【摘要】：在吸收光谱领域特别是可调谐半导体激光直接吸收光谱(dTDLAS)技术中,需要精确测量吸收光谱的积分吸光度值以精确反演出流场温度、组分浓度等参数。对于非均匀流场,单光路吸收光谱测量时,由于沿测量路径的谱线展宽随流场状态的变化而变化,见诸文献的研究主要采用Voigt或Lorentz线型对吸光度曲线拟合处理或直接对吸光度曲线数值积分获取积分吸光度值,针对方法可能引入的误差进行了模拟分析,并提出Voigt线型两翼拟合吸光度的方法来获取吸收光谱的积分吸光度值,以减小拟合误差。采用流场测量中常用的H_2O作为目标气体,选取了8条具有不同低态能级的吸收线,以实验室平焰炉为原型建立两种非均匀流场模型,并通过分段法对流场非均匀性进行等效处理。分别采用Voigt线型拟合法、数值积分法和Voigt线型两翼拟合法模拟计算两模型的积分吸光度值,通过与理论积分吸光度值对比得出各方法的误差大小,从而确定出在不同的非均匀流场情况下相适应的积分吸光度值获取方法。
[Abstract]:In the absorption field, especially in the tunable semiconductor laser direct absorption spectroscopy (dTDLAS) technology, it is necessary to accurately measure the integral absorbance of the absorption spectrum in order to accurately reverse the flow field temperature, component concentration and other parameters. For the non-uniform flow field, the spectral broadening along the measurement path varies with the state of the flow field. Voigt or Lorentz lines are used to fit the absorbance curve or to obtain the integral absorbance value directly by numerical integration of the absorbance curve. The possible errors introduced by the method are simulated and analyzed. In order to reduce the fitting error, the method of fitting absorbance of Voigt linear two wings is proposed to obtain the integral absorbance of absorption spectrum. Eight absorption lines with different low energy levels are selected by using H _ 2O as the target gas in flow field measurement. Two kinds of non-uniform flow field models are established using the flat flame furnace as the prototype. The inhomogeneity of the flow field is treated by the piecewise method. The integral absorbance values of the two models are calculated by using the Voigt fitting method, the numerical integration method and the Voigt linear fitting method, respectively. The error of each method is obtained by comparing with the theoretical integral absorbance. Thus, the method of obtaining integral absorbance value under different non-uniform flow field is determined.
【作者单位】：中国科学院安徽光学精密机械研究所环境光学与技术重点实验室;中国科学技术大学;上海卫星工程研究所;
【基金】：国家重大科学仪器设备开发专项项目(2014YQ060537)资助
【分类号】：O657.3

【参考文献】