FLASHBACK PROPENSITY OF SYNGAS FUELS

摘要

The paper presents experimental measurements of flashback propensity of H_2-CO mixtures (primary constituents of syngas fuels). Effects of H_2 concentration, external excitation and swirl on the flashback propensity of H_2-CO flames are discussed. The flashback behavior of H_2-CO flames changes nonlinearly with the increase in H_2 contents in the mixture. The critical velocity gradient (g_F) values of 5%-95% and 15%-85% H_2-CO mixtures somewhat agree with the scaling relation (g_F = c S_L~2/α) and yield an average c value of 0.035. However, the gF values of 25%-75% H_2-CO mixture show higher order variations with the S_L~2/a ratio (especially for S_L~2/a > 19,000 s"1). At a lower S_l~2/α ratio, burner diameters have small effects on critical velocity gradient measurements; however, the effect is significant at higher S_l~2/α ratio. The effect of external excitation on the flashback propensity of H_2-CO flames with more than 5% H_2 is not significant. Flashback through two mechanisms and their dependence on combustor parameters were also identified for swirl stabilized H_2-CO flames.