基于激光吸收光谱技术的在线层析成像算法  

Online tomography algorithm based on laser absorption spectroscopy

作　　者：赵荣 周宾 刘奇 戴明露 汪步斌 王一红 Zhao Rong;Zhou Bin;Liu Qi;Dai Ming-Lu;Wang Bu-Bin;Wang Yi-Hong(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,School of Energy and Environment,Southeast University,Nanjing 210096,China;School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]东南大学能源与环境学院,能源热转换及其过程测控教育部重点实验室,南京210096 [2]南京理工大学电子工程与光电技术学院,南京210094

出　　处：《物理学报》2023年第5期149-161,共13页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFB0603204);国家自然科学基金(批准号:50976024,50906013)资助的课题。

摘　　要：传统的免标定波长调制光谱方法一般需要结合光谱数据库和激光调制参数进行复杂的吸收光谱模拟,对先验光谱参数的准确度和硬件参数提出了很高的要求,同时不合适的初值会增加计算时间,甚至会导致陷入局部最优解.为提高计算效率,本文引入一种快速免标定波长调制光谱技术获取积分吸光度.该方法对光谱数据库的依赖性低,计算效率高,同时解决了传统方法在高温高压下由于吸收谱线展宽变大而导致的谐波信号不完整问题.进一步将该方法应用于非均匀复杂燃烧场层析成像,并结合所提成像系统实现了快速在线重建温度、浓度分布.通过数值模拟和丁烷喷灯燃烧火焰的实验验证该方法获得积分吸光度的准确性和计算效率.结果表明,与传统的波长调制方法相比重建分布基本一致,最大测量相对偏差仅为0.94%,与热电偶测量值相比最大相对偏差为3.5%,验证了该方法的准确性.在重建精度相当的前提下,分析两种方法获得积分吸光度的计算效率.所引方法和传统方法平均每路计算时间分别为0.15 s和21.10 s.所引方法的计算效率比传统方法至少提高了2个数量级,为实现在线重建燃烧场的温度、浓度分布提供了快速可靠的研究方法和技术手段.Conventional calibration-free wavelength modulation spectroscopy generally requires complex absorption spectrum simulations in combination with spectral databases and laser modulation parameters,placing high demands on the accuracy of a priori spectral parameters and hardware parameters.Meanwhile,inappropriate initial values can increase the computation time and even lead to local optimal solutions.In order to improve the computational efficiency,a rapid calibration-free wavelength modulation spectroscopy to obtain the integrated absorbance is presented in this work.First,this method is computationally efficient,requiring only algebraic calculations by using the 2nd,4th,and 6th harmonic center peak height parameters to obtain the integrated absorbance,eliminating the need for computationally intensive harmonic fitting calculations.Secondly,this method has low dependence on the spectral database,requiring only line intensity and low-state energy level spectral parameters.Finally,this method is highly adaptable and does not require scanning the complete absorption spectral line shape,which solves the problem of incomplete harmonic signals caused by the conventional method at high temperature and high pressure due to the broadening of the absorption spectral line.This method has previously been used only for line-of-sight measurements at low-frequency experimental signals in stable environments,and for calculating the integrated absorbance at average temperature,concentration and pressure states.In this work,the method is applied to non-uniform complex combustion field tomography and combined with the proposed tomographic system to achieve online reconstructing temperature and concentration distributions.The accuracy and computational efficiency of the method in obtaining the integrated absorbance are verified by numerical simulations and experiments on the butane burner flame.The results show that the presented method is consistent with the reconstructed distribution compared with the conventional wavelength modula

关 键 词：在线层析成像 激光吸收光谱 波长调制光谱 复杂燃烧场 

分 类 号：TN24[电子电信—物理电子学]