Absolute concentration measurements using DFWM and modeling of OH and S-2 in a fuel-rich H-2/Air/SO2 flame

Concentration profiles of OH and S-2 in a sulfur-containing premixed H-2/ai r flame were obtained and compared to numerical calculations. The measureme nts utilized degenerate four-wave mixing and absorption spectroscopy in par allel (MULTIPLEX spectroscopy) and were numerically simulated for a one-dim ensional flat flame. An established reaction mechanism for hydrogen oxidati on was extended by reactions for the sulfur chemistry drawn from the litera ture. The experimental results for the OH and S-2 concentration profiles ar e in good qualitative agreement with the simulations. However, the model ca lculations underestimate the S-2 concentrations by two orders of magnitude, indicating that important intermediates and reactions could have been omit ted. (C) 1999 by The Combustion Institute.