Flame laser

For the analysis of the chemical structure of flames, laser methods will typically provide temperature measurement and concentration profiles of some readily detectable radicals. The following two examples compare selected LIF and CRDS results. Figure 2.1 presents the temperature profile in a fuel-rich (C/O = 0.6) propene-oxygen-argon flame at 50 mbar [42]. For the LIF measurements, 1% NO was added. OH-LIF thermometry would also be possible, but regarding the rather low OH concentrations in fuel-rich flames, especially at low temperatures, this approach does not capture the temperature rise in the flame front [43]. The sensitivity of the CRDS technique, however, is superior, and the OH mole fraction is sufficient to follow the entire temperature profile. Both measurements are in excellent agreement. For all flames studied here, the temperature profile has been measured by LIF and/or CRDS. 

D. Escudi4 P- Paranthoen, and M. Trinite 1983, Modification of turbulent tiow-field by an oblique premixed hydrogen-air flame, in Flames, Laser and Reactive Systems (selected papers from the Eighth International Colloquium on Gasdynamics of Explosions and Reactive Systems), Progress in Astronautics and Aeronautics Series, AIAA Inc. publishers, pp. 147-163. 

Hybrid systems which have been used to determine metals in solids include ETV-ICP, spark-MIP, spark-flame, arc-flame, laser-flame, laser-ETA and laser-DCP. ETV-ICP-MS is a solid sampling process which is automated, multi-element with high detection power, and amongst the best currently achieved. 

A. M. Klimov, Dokl. Akad. Nauk SSSR 221, 56 (1975) Premixed Turbulent Flames—Interplay of Hydrodynamic and Chemical Phenomena, in Flames, Lasers and Reactive Systems, vol. 88 of Progress in Astronautics and Aeronautics, J. R. Bowen, N. Manson, A. K. Oppenheim and R. I. Soloukhin, eds.. New York American Institute of Aeronautics and Astronautics, 1983, 133-146. 

Fig. 127. Flame laser enhanced ionization spectrometry [670, 671]. (a) Flashlamp/dye laser, (b) high voltage, (c) trigger photodiode, (d) preamplifier, (e) pulse amplifier, (f) active filter, (g) boxcar averager, (h) chart recorder. (Reprinted with permission from Ref. [671]).

Flame laser enhanced ionization and flame laser induced atomic fluorescence can be used as sensitive detectors for organo tin compounds. 

Figure 50. Flame laser-enhanced ionization spectrometry (0)...

Xian, K. Li, Z. Staude, S. Li, B. Sim, Z. Lantz, A. Alden, M. Atakan B. (2009). Influence of ferrocene addition to a laminar premixed propene flame Laser diagnostics, mass spectrometry and numerical simulations, Proc. Combust Inst, Vol. 32, pp. 445-452, ISSN 1540-7489... 

---