Effect of pressure on counterflow H2-air partially premixed flames

A computational investigation of high-pressure hydrogen-air partially premixed flames (PPF) was presented to characterize the effect of pressure on flame structure, and to examine the relevance of reaction limits in the context of H2/air PPF. Increasing pressure reduced the flame speed and the diffusive losses of H-atoms out of the rich premixed zone, induced transition from the first to the second reaction limit in this zone, and caused this zone to move closer to the non-premixed zone. Further increase pressure led to a merged flame, and a transition to the third reaction zone. Soret effect on the PPF was observed to induce an earlier transition (at lower pressure) from the state dominated by H-O2 branching to the estates dominated by H-O2 termination in the rich premixed zone. This is an abstract of a paper presented at the 30th International Symposium on combustion (Chicago, IL 7/25-30/2004).