Kempema Nathan J, Long Marshall B
Appl Opt. 2014 Oct 10;53(29):6688-97. doi: 10.1364/AO.53.006688.
This work demonstrates structured laser illumination planar imaging (SLIPI) for Rayleigh thermometry with high background scattering. Two coherent laser beams were crossed to produce an interference pattern, from which the modulated Rayleigh signal was collected. The modulated signal serves as a signature that identifies information about Rayleigh scattering from the probe volume against additional contributions in the image from background scattering. This work shows that the structured nature of the illumination allows for a simplified background correction. The experimental approach is validated in a non-premixed methane/air flame, and the temperature is found to be in excellent agreement with previous experimental and computational results. Rayleigh SLIPI is then applied to a high background scattering application as part of the full-field temperature measurement of sooting non-premixed ethylene/air flames. For these flames, standard Rayleigh background corrections are impossible since scattering from soot just outside the field of view is the main source of the background. Good agreement is found between SLIPI and intensity-ratio thin-filament pyrometry-derived temperature along their adjoining interface in the flame.
这项工作展示了用于高背景散射瑞利测温的结构化激光照明平面成像（SLIPI）。交叉两束相干激光以产生干涉图样，从中收集调制后的瑞利信号。该调制信号作为一种特征，可识别来自探测体积的瑞利散射信息，以对抗图像中背景散射的额外贡献。这项工作表明，照明的结构化特性允许进行简化的背景校正。该实验方法在非预混甲烷/空气火焰中得到验证，发现温度与先前的实验和计算结果高度吻合。然后，瑞利SLIPI被应用于高背景散射应用，作为烟炱非预混乙烯/空气火焰全场温度测量的一部分。对于这些火焰，由于视野外烟炱的散射是背景的主要来源，因此无法进行标准的瑞利背景校正。在火焰中，SLIPI与强度比细丝高温计得出的温度在其相邻界面处吻合良好。
