Measurements from flame chemiluminescence tomography of forced laminar premixed propane flames
Measurements from flame chemiluminescence tomography of forced laminar premixed propane flames
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DOI：
10.1016/j.combustflame.2017.05.003
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发表时间：
2017-09
影响因子：
4.4
通讯作者：
S. Wiseman;M. Brear;R. Gordon;I. Marusic
中科院分区：
文献类型：
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作者：
S. Wiseman;M. Brear;R. Gordon;I. Marusic
两个非轴对称的、强迫的、层流的、预混的、丙烷-空气火焰的不稳定的、可见的化学发光场，用3到36个等间距的视图进行了层析重建。演示了测量火焰表面积、火焰曲率、火焰厚度和火焰传播速度的法向分量（表面速度）的算法。然后评估每个测量对重建中使用的视图数量的敏感性。对于所研究的两种火焰，使用36个视图测量的火焰表面积波动与使用少至9个视图测量的火焰表面积波动之间的差异小于1%。对于其他三个量，在每个火焰的强制循环的一个阶段获得整个火焰表面的测量样本。通过评估使用最大视图数获得的测量分布与使用较少视图获得的测量分布的相似性来比较对视图数的敏感性。随着观察次数的增加，表面速度测量分布收敛速度最快，尽管平均曲率的结果相似。然而，火焰厚度测量分布的收敛速度明显较慢，测量火焰厚度所需的视图数是曲率或表面速度的两倍以上。所展示的测量算法一般适用于起皱、预混火焰的化学发光场。结果表明，对于实验室规模的、弱湍流的、预混的、喷射的火焰，火焰曲率和表面速度的统计测量只需6个视图就可以准确地获得，而火焰厚度的有用测量可能需要超过20个视图。
The unsteady, visible, chemiluminescence fields of two non-axisymmetric, forced, laminar, premixed, propane–air flames are tomographically reconstructed using between 3 and 36 equally-spaced views. Algorithms for measuring flame surface area, flame curvature, flame thickness, and the normal component of the flame propagation velocity (surface speed) are demonstrated. The sensitivity of each measurement to the number of views used in the reconstruction is then assessed. For both flames studied, the difference between flame surface area fluctuations measured using 36 views and those measured using as few as 9 views was less than 1%. For the other three quantities, a measurement sample is acquired over the entire flame surface at one phase of the forcing cycle for each flame. The sensitivity to the number of views is compared by assessing the similarity of measurement distributions obtained using the maximum number of views to those obtained using fewer views. The surface speed measurement distribution is found to converge fastest as the number of views was increased, though results for mean curvature are similar. However, the flame thickness measurement distribution was found to have significantly slower convergence and more than twice the number of views are required to measure flame thickness compared to curvature or surface speed. The demonstrated measurement algorithms are generally applicable to the chemiluminescence fields of wrinkled, premixed flames. The results suggest that for laboratory-scale, weakly turbulent, premixed, jet flames, statistical measurements of flame curvature and surface speed may be accurately obtained using as few as six views, while greater than 20 views are likely to be required to obtain useful measurements of flame thickness.