一种基于TDLAS的高分辨率二维温度场重建算法及数值仿真

发展了一种基于TDLAS正交光路的二维燃烧场温度重建算法,为了评价该重建方法,数值仿真了2N (N≥3)条视线(Light-of-sight,LOS)测量路径呈N×N均匀排布时对两种不同的温度场的二维重建结果,并定义了最大偏差和平均偏差两个物理量来描述N值对重建结果的影响。结果表明,对于对称的单峰非均匀温度场,重建的温度场最大偏差在50K(2.5%)以内,最大偏差随N的奇偶而波动,其总体趋势随N增大而减小;平均偏差随着N的增大而减小,N≥9时最大偏差和平均偏差的改善均已不明显;对于双峰温度场,用该方法二维重建的结果最大偏差超过350K(15.2%),平均偏差大于0.03,并出现严重失真,此时可通过额外布置斜穿待测场的测量路径来改善测量结果。研究结果对实际的二维测量系统的搭建和应用有指导意义。

A high-resolution algorithm for 2D temperature reconstruction using TDLAS and numerical simulation

We develop a tunable diode laser absorption tomography algorithm for two-dimen-sional (2D)temperature reconstruction based on orthogonal optical paths.In order to evaluate the reconstruction method,we analyzed the 2D reconstruction results of two different tempera-ture phantoms by means of numerical simulation of N×N uniform grid arrangement consisting of 2N (N≥3)light of sight (LOS)measurement path.The maximum deviation and the mean devi-ation were defined to describe the effect of the value of N on the reconstruction results.The re-sults show that for the single symmetrical peak non-uniform temperature phantom,the maxi-mum deviation of the reconstruction temperature is less than 50K(2.5%),the maximum devia-tion fluctuates with N parity and the overall trend is decrease with N increasing.The mean devia-tion is reduced as N increases,which means the reconstruction is better with N increasing.But when N≥9 ,the improvements are not distinct any more.For the bimodal temperature phantom, the maximum deviations of the results using this 2D reconstruction method are more than 350K (15.2%)and the mean deviations are greater than 0.03.What’s worse,there is a serious distor-tion.However,the reconstruction results can be improved by added measurement path diagonal-ly across the tested temperature field.The study is helpful for the real 2D measurement system setup and actual application.