TEMPORALLY RESOLVED SPECIES MEASUREMENTS IN A FLICKERING AIR-DILUTED, NON-PREMIXED NATURAL GAS FLAME BY EXTRACTIVE SAMPLING OF FLAME GASES AND FOURIER TRANSFORM IR ANALYSIS

摘要

Spatially and temporally resolved concentrations of carbon monoxide, carbon dioxide, methane, and acetylene are presented for a 10 Hz, acoustically forced, air-diluted natural gas flame with a fuel mixture equivalence ratio of 3.3. Samples were withdrawn from the flame using a modified quartz microprobe designed to minimize dead volume in the probe during the sampling event. Valve opening and closing were synchronized to the forcing waveform. Extracted gases were analyzed using on-line Fourier transform IR spectrometry. Concentrations were determined using a combination of singular value decomposition matrix techniques and fitting of rotational line sequences. In both techniques, samples were calibrated using data collected in a well-characterized methane/air diffusion flame supported on a Wolfhard-Parker slot burner. Because these four species comprise most of the carbon in the flame, their concentrations can be used to estimate the mass fraction of carbon and thus mixture fraction. Contour maps of all four species and mixture fraction are presented.