Raman/Rayleigh/LIF Measurements in a Turbulent CH4/H2/N2 Jet Diffusion Flame: Experimental Techniques and Turbulence-Chemistry Interaction

Abstract Single-shot Raman, Rayleigh, and laser-induced fluorescence (LIF) measurements have been performed simultaneously in a turbulent jet flame (Re = 15,200) in order to determine joint probability density functions of temperature, mixture fraction, major species (CH4, H2, O2, N2, H2O, CO2, CO), and minor species (OH, NO) mass fractions. The flame is used as a “standard flame” 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 paper, the results obtained at the Sandia National Laboratories are compared with those from Raman/Rayleigh measurements performed earlier at the Deutsches Zentrum fur Luft-und Raumfahrt, or German Aerospace Center (DLR). The agreement between the different data sets is generally good, and most of the observed deviations are within experimental uncertainties. The remaining discrepancies are discussed. The main issues of the second part are the characterization of the thermochemical state of the flame and the study of the influence of increasing the Reynolds number to Re = 22,800. Effects of finite-rate chemistry, local flame extinction, NO formation, and nonequilibrium concentrations are discussed.