Two-Wavelength Single Laser CH and CH4 Imaging in a Lifted turbulent Diffusion Flame. (Reannouncement with New Availability Information).

摘要

A new technique has been developed which allows simultaneous 2-D mapping of CH and CH4 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 system of CH, and the fluorescence of the (0,1) transition is observed at 489 nm. Coincidentally, the spontaneous Raman scattering from CH4 also occurs near 489 nm for a 431.5-nm excitation. To separate the CH4 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 CH4 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.