Numerical modeling of plasma-assisted combustion effects on firing and intermediates in the combustion process of methanol–air mixtures

Abstract

The effects of plasma-assisted ignition and combustion on the ignition-delay time (Tid) and intermediates in methanol combustion were simulated numerically through a chemical-kinetics mechanism of methanol oxidation. Plasma-assisted ignition can considerably shorten the Tid. Plasma-assisted ignition is more conducive to a low temperature and the lean combustion of a methanol-air mixture. According to the shortest Tid, the active particle order is: O < CH3O < 220 Td < H < OH < CH2OH < CH3 < autoignition. The concentration of O atoms in active particles affects the Tid shortening. Plasma-assisted combustion can significantly shorten the time for the system temperature to reach a maximum. The concentrations of the reactants CH3OH and O2 decrease sharply for autoignition after the ignition-delay period, and the products CO, CO2 and H2O increase rapidly. In plasma-assisted combustion, the addition of active particles significantly increases the rate of chemical reaction of consumption of O2, promotes the rapid redox reaction of methanol–air mixtures, oxidizes methanol fuel to CO2 and H2O more rapidly, and accelerates combustion. The sensitivity coefficients of temperature and Tid for plasma-assisted combustion are lower than those for autoignition.