Time-averaged tomographic absorption spectroscopy for H2O diffusion in turbulent jet flow at room temperature
Time-averaged tomographic absorption spectroscopy for H2O diffusion in turbulent jet flow at room temperature
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DOI：
10.1016/j.ijhydene.2023.08.230
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发表时间：
2023-12-16
影响因子：
7.2
通讯作者：
Ren，Wei
中科院分区：
文献类型：
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作者：
Shi，Dingfeng;Cheong，Kin-Pang;Ren，Wei
层析吸收光谱（TAS）技术对于氢燃料和碳氢燃料在各种流场中的燃烧诊断具有重要意义。在这项研究中，我们提出并进行了时间平均TAS的平均H2O摩尔分数XH2O在干燥的，轴对称的，湍流射流与雷诺数为5670的重建，以揭示湍流吸收光谱测量的效果。选择1368.598 nm附近的H2O吸收线，并在1 kHz下扫描。湍流对TAS的影响与沿光路沿着方向的湍流强度成正相关关系，通过时间平均可以有效地减小湍流对TAS的影响。结果表明，对于时间平均TAS，需要适当选择扫描速率和统计收敛的时间步长数。通过对积分吸光度进行时间平均和平滑处理，重建了XH2O的二维平均分布，结果与CFD模拟结果吻合较好.当平均时步数为30000时，测量结果的平均偏差可减小25%以上。本研究突出了TAS的可视化和诊断的复杂流动，如湍流非反应流和湍流燃烧的潜力。
Tomographic absorption spectroscopy (TAS) is important for the combustion diagnostics of hydrogen and hydrocarbon fuels in various flow fields. In this study, we proposed and conducted time-averaged TAS for the reconstructions of mean H2O mole fractionXH2Oin a dry, axisymmetric, turbulent jet flow with a Reynolds number of 5670 to reveal the effect of turbulence on absorption spectroscopy measurement. The absorption line of H2O near 1368.598 nm was selected and scanned at 1 kHz. The effect of turbulence on TAS, which is positively related to the turbulent intensity along the optical path, has been confirmed and can be effectively alleviated by conducting time averaging. It is shown that the proper selections of scan rate and the number of time steps for statistical convergence are required for time-averaged TAS. With time averaging and smoothing operations on the integrated absorbance, the two-dimensional meanXH2Odistributions were reconstructed with the present method and the result showed a good agreement with CFD simulation. The mean deviation of the measured results can be reduced by over 25% when the number of time steps for average is 30000. The present study highlights the potential of TAS for the visualization and diagnostics of complex flows such as turbulent non-reactive flow and turbulent combustion.