合肥工业大学汽车与交通工程学院，安徽 合肥 230009
Abstract：Based on the CHEMKIN software, the effect of methanol addition on the two-stage ignition of n-heptane at high and low temperatures is investigated to reveal the interaction mechanism between methanol and n-heptane in the ignition process, and the corresponding kinetic study is carried out. The results show that at the initial low temperature, the competition of methanol for OH radicals inhibits the low-temperature chain branching reaction of n-heptane, which prolongs the first-stage ignition of the fuel. With the increase of methanol substitution percent，the intensity of the low-temperature reaction is further inhibited and no obvious low-temperature ignition phenomenon could be detected. However, the increase in the concentration of HO2 radicals after methanol addition promotes H2O2production. HH2O2generates a large amount of OH radicals through decomposition reaction at high temperature, which promotes the second-stage ignition. In contrast to the inhibitory effect of methanol at low initial temperatures, the ignition time at high initial temperatures is significantly advanced by blending a few amounts of methanol, but the ignition time is gradually delayed again by blending an excessive amount of methanol.
Keywords:methanol; n-heptane; ignition delay; chemical reaction kinetics