SIMULTANEOUS RAMAN LIF MEASUREMENTS OF MAJOR SPECIES AND NO IN TURBULENT H-2/AIR DIFFUSION FLAMES/

A single-pulse spontaneous Raman scattering apparatus, based on a flas hlamp-pumped dye laser, was used to determine the concentrations of th e major species and the temperature in turbulent H-2/N-2/air jet diffu sion flames. The concentrations of nitric oxide were simultaneously me asured by Laser-Induced Fluorescence (LIF) after excitation of the A(2 ) Sigma(+)-X(2) Pi transition with a Nd:YAG-pumped dye laser. Some fun damentals of the employed methods, including the calibration procedure , quenching corrections, and accuracy are discussed. Besides a detaile d study of the experimental technique, a main goal of the presented in vestigations was the generation of comprehensive data sets of high acc uracy from well-defined turbulent flames which allow for a quantitativ e comparison with model calculations. Two flames with different fuel d ilution and Reynolds numbers were investigated in a pattern of typical ly 100 measuring locations each comprising 300 single shots. In additi on, four flames with different flow velocities but same fuel compositi on were compared with respect to their temperature and NO concentratio n profiles. The results show that differential diffusion plays an impo rtant role in these flames, especially near the flame base, where the temperature is increased above the adiabatic flame temperature and dev iations from adiabatic equilibrium are large. The correlations between NO and mixture fraction and NO and temperature reveal characteristic features of the different flames.