Analysis of spatial temperature and gas concentration distributions is of great importance for combustion research. Algebraic reconstruction technique (ART) and adaptive algebraic reconstruction technique (AART) based on tunable diode laser absorption spectroscopy are both widely used methods for temperature tomographic imaging in a flame. After being obtained the temperature tomography through iterative method, the gas concentration reconstruction could be determined from a simple division equation (direct gas concentration algorithm) or iterative algorithm (ART gas concentration algorithm or AART gas concentration algorithm) for the second time. For the latter, iterative algorithm was used twice through the whole process. A series of numerical simulations were carried out by three gas concentration reconstruction methods mentioned above. The results demonstrated that AART method had better robustness for different phantoms and stability in the case that measured projections contained different levels of noise. Experimental measurements in a flat methane/air flame on a McKenna burner under three different equivalence ratios (1.0, 0.9, and 0.8) were conducted using AART gas concentration algorithm. The reconstructed results coincide well with those results obtained by thermocouple and theoretical calculation. Both simulation and experiment demonstrate that the AART gas concentration algorithm would be reliable and suitable for simultaneous temperature and H2O concentration tomographic imaging during combustion. As a consequence, this method has unrivalled potential for two-dimensional combustion diagnosis.

中文翻译：

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基于可调二极管激光吸收光谱的火焰温度和H ₂ O浓度同时成像的气体浓度重建方法研究

空间温度和气体浓度分布的分析对于燃烧研究非常重要。基于可调谐二极管激光吸收光谱的代数重建技术（ART）和自适应代数重建技术（AART）都是在火焰中进行温度层析成像的广泛使用的方法。通过迭代方法获得温度层析成像后，第二次可通过简单除法方程（直接气体浓度算法）或迭代算法（ART气体浓度算法或AART气体浓度算法）确定气体浓度重建。对于后者，在整个过程中两次使用了迭代算法。通过上述三种气体浓度重建方法进行了一系列数值模拟。结果表明，在测量的投影包含不同级别的噪声的情况下，AART方法对于不同的体模具有更好的鲁棒性和稳定性。使用AART气体浓度算法，在McKenna燃烧器上的甲烷/空气平面火焰中，在三种不同的当量比（1.0、0.9和0.8）下进行了实验测量。重建结果与通过热电偶和理论计算获得的结果非常吻合。仿真和实验均表明，AART气体浓度算法将是可靠的，适用于燃烧期间同时进行温度和H2O浓度的层析成像。结果，该方法在二维燃烧诊断中具有无与伦比的潜力。