Abstract
It has been described earlier that imaging measurements of laser-induced fluorescence (LIF) in flames can be calibrated to number densities with an integrated absorption measurement provided the integrated absorption is small. In this paper a method is presented that extends the technique to flames with substantial absorption, improves the number density determination and allows the experimental parameters to be chosen more freely. The method is based on an iterative computer procedure that reconstructs the 1-D spatially resolved absorption profile from laser measurements of the 1-D spatially resolved LIF and the integrated absorption of the laser beam. The technique is experimentally demonstrated by measurements of OH number densities in atmospheric flames. It is potentially a single-pulse method. Other applications of the iterative procedure are mentioned.
Similar content being viewed by others
References
A.C. Eckbreth, P.A. Bonczyk, J.F. Verdieck: Progr. Energy Combust. Sci.5, 253 (1979)
Laser Probes for Combustion Chemistry, ed. by D.R. Crosley, ACS Symposium Series (American Chemical Society, Washington, DC 1980)
M.J. Dyer, D.R. Crosley: Opt. Lett.7, 382 (1982)
M. Aldén, H. Edner, G. Holmstedt, S. Svanberg, T. Högberg: Appl. Opt.21, 1236 (1982)
G. Kychakoff, R.D. Howe, R.K. Hanson: Appl. Opt.23, 704 (1984)
A.P. Baronavski, J.R. McDonald: Appl. Opt.16, 1897 (1977)
D. Stepowski, A. Garo: Appl. Opt.24, 2478 (1985)
D.A. Skoog, D.M. West:Principles of Instrumental Analysis (Holt-Saunders International, Japan 1980)
R.J. Cattolica: Comb. Flame44, 43 (1982)
A.C.G. Mitchell, M.W. Zemansky:Resonance Radiation and Excited Atoms (Cambridge Univ. Press, London 1971)
H.M. Hertz, M. Aldén: “Pulsed laser method for local OH number density determination in flames by 1-D spatially resolved absorption measurements”, Lund Reports on Atomic Physics LRAP-62, Lund Inst. of Tech., Lund, Sweden (1986)
J.W. Goodman:Introduction to Fourier Optics (McGraw-Hill, New York 1968)
M. Nadler, W.E. Kaskan: J. Quant. Spectr. Rad. Transf.10, 25 (1970)
P.E. Rouse, R.J. Engleman: J. Quant. Spectr. Rad. Transf.13, 1503 (1973)
R.M. Measures:Laser Remote Sensing (Wiley, New York 1984)
A.D. Burden, H.M. Hertz: “Calibration of imaging laserinduced fluorescence measurements in highly absorbing flames: Analytical reconstruction method”, Lund Reports on Atomic Physics LRAP-68, Lund Inst. of Tech., Lund, Sweden (1986)