Raman/Rayleigh/LIF measurements in a turbulent CH4/H-2/N-2 jet diffusion flame: Experimental techniques and turbulence-chemistry interaction

Single-shot Raman, Rayleigh, and laser-induced fluorescence (LIF) measureme nts have been performed simultaneously in a turbulent jet flame (Re = 15,20 0) in order to determine joint probability density functions of temperature , mixture fraction, major species (CH4, H-2, O-2, N-2, H2O, CO2, CO), and m inor species (OH, NO) mass fractions. The flame is used as a "standard flam e" within the TNF Workshop, and therefore, comprehensive and accurate data sets are required to allow a quantitative comparison with predictions from computational fluid dynamics (CFD) calculations. In the first part of the p aper, the results obtained at the Sandia National Laboratories are compared with those from Raman/Rayleigh measurements performed earlier at the Deuts ches Zentrum fur Luft-und Raumfahrt, or German Aerospace Center (DLR). The agreement between the different data sets is generally good, and most of th e observed deviations are within experimental uncertainties. The remaining discrepancies are discussed. The main issues of the second part are the cha racterization of the thermochemical state of the flame and the study of the influence of increasing the Reynolds number to Re = 22,800. Effects of fin ite-rate chemistry, local flame extinction, NO formation, and nonequilibriu m concentrations are discussed. (C) 2000 by The Combustion Institute.