Namazian M, Schmitt R L, Long M B
Appl Opt. 1988 Sep 1;27(17):3597-600. doi: 10.1364/AO.27.003597.
A new technique has been developed which allows simultaneous 2-D mapping of CH and CH 4 in a turbulent methane flame. A flashlamp-pumped dye laser using two back mirrors produces output at 431.5 and 444 nm simultaneously. The 431.5-nm line is used to excite the (0, 0) band of the A(2)Delta-X(2)Pi system of CH, and the fluorescence of the (0, 1) transition is observed at 489 nm. Coincidentally, the spontaneous Raman scattering from CH(4) also occurs near 489 nm for a 431.5-nm excitation. To separate the CH(4) and CH contributions, the 444-nm line is used to produce a spontaneous Raman signal from CH(4) that is spectrally separated from the CH fluorescence. Subtraction of the signals generated by the 431.5- and 444-nm wavelength beams yields separate measurements of CH(4) and CH. Raman-scattered light records the instantaneous distribution of the fuel, and simultaneously the CH fluorescence indicates the location of the flame zone. The resulting composite images provide important insight on the interrelationship between fuel-air mixing and subsequent combustion.M. Namazian is with Altex Technologies Corporation, 109 Via De Tesoros, Los Gatos, California 95030; R. L. Schmitt is with Sandia National Laboratories, Combustion Research Facility, Livermore, California 94550; and M. B. Long is with Yale University, Department of Mechanical Engineering, New Haven, Connecticut 06520.
已开发出一种新技术，可在湍流甲烷火焰中同时对CH和CH₄进行二维映射。使用两个后向镜的闪光灯泵浦染料激光器同时在431.5和444 nm产生输出。431.5 nm谱线用于激发CH的A(2)Δ-X(2)Π系统的(0, 0)带，并在489 nm处观察(0, 1)跃迁的荧光。巧合的是，对于431.5 nm的激发，CH₄的自发拉曼散射也发生在489 nm附近。为了分离CH₄和CH的贡献，444 nm谱线用于产生与CH荧光在光谱上分离的CH₄自发拉曼信号。减去由431.5和444 nm波长光束产生的信号，可分别测量CH₄和CH。拉曼散射光记录了燃料的瞬时分布，同时CH荧光指示了火焰区的位置。所得的合成图像为燃料 - 空气混合与后续燃烧之间的相互关系提供了重要的见解。M. 纳马齐安就职于阿尔泰克斯技术公司，地址为加利福尼亚州洛斯盖托斯市特索罗斯路109号，邮编95030；R. L. 施密特就职于加利福尼亚州利弗莫尔市桑迪亚国家实验室燃烧研究设施，邮编94550；M. B. 朗就职于康涅狄格州纽黑文市耶鲁大学机械工程系，邮编06520。
