Abstract
In this study, effects of dilution with CO, on combustion mechanisms and the local burning velocity of two-component fuel mixtures of DME, hydrogen and methane were investigated by chemical kinetics computations. Lean and rich mixtures having nearly the same laminar burning velocity were prepared by adding CO_2 to mixtures where the fuel mixing rate 6 is varied from 0 to 1 at equivalence ratios of 0.4-3.0. As a result, it is elucidated that Markstein numbers of mixtures diluted with CO, are smaller than that of mixtures diluted with N2. Those of lean mixtures changed monotonically with increasing 6 depending on the Lewis number, however, those of moderately and highly rich flames showed a complicated trend in each condition with change in the equivalence ratio and 6. These characteristics of response to flame stretch were discussed in light of the chemical reaction mechanisms.
