Influence of co-existing lower alkanes on ignition of n-heptane/air mixture

(Comparison of methane and propane co-existence)

Abstract

In the previous study, it was shown that the ignition delay time of n-heptane/air mixture co-existing with propane was longer than the case of methane co-existence in a range of 800-900K, though octane number of propane was lower than that of methane. In this study, in order to investigate the effect of propane co-existence, chemical kinetic analysis of the ignition process of n-heptane/air mixture under co-existence of methane or propane was performed. As a result, low temperature oxidation (LTO) of n-heptane was suppressed by co-existing propane, because the reactivity of propane with OH radical was higher and propane consumed OH radicals than methane. The delay effect by propane was limited to a high temperature side of LTO range, since propane has weak LTO mechanism at a temperature range near 700K, which canceled out the OH radical consumption.