Laminar Combustion Characteristics of Spherically Propagating Ethyl Methyl Carbonate Flames

Abstract

The laminar combustion characteristics of ethyl methyl carbonate flames were investigated at initial pressures of 70–130 kPa, equivalence ratios of 0.6–1.4, and an initial temperature of 373 K using a 36 L constant volume combustion chamber. The Grégoire mechanism well predicts the laminar burning velocity, pressure power exponent, and isochoric combustion pressure. The laminar burning velocity of ethyl methyl carbonate increases from 25.99 to 49.21 cm/s at an initial pressure of 100 kPa as the equivalence ratio increases from 0.6 to 1.0. Moreover, the Jin method, which assumes that one mole of ethyl methyl carbonate is decomposed into 2 mol of CH4, 1 mol of CO, and 1 mol of CO2, cannot accurately predict the laminar burning velocity of the mixtures. The pressure power exponent indicates that the pressure dependence is more inconspicuous for the mixtures near the stoichiometric ratio. The maximum isochoric combustion pressure and maximum rate of pressure rise vary nonmonotonically with the equivalence ratio, reaching a maximum at ϕ = 1.2. Empirical expressions for the experimentally obtained combustion characteristics as a function of the initial pressure and equivalence ratio were established. The reactions R806: CCOC*OOC = C2H4 + COC*OOH and R797: CCOC*OOC + H = CCJOC*OOC + H2 had the greatest effect on promoting and inhibiting the laminar burning velocity in the decomposition reaction, respectively. The sum of the peak mole fractions of H/O/OH radicals, the sum of the rate of production of the key radicals, and the heat release rate all reach their maximum values at ϕ = 1.1. The reactivity of ethyl methyl carbonate is mainly controlled by reactions involving COC*OOH. The maximum rate of pressure rise can be predicted by the sum of the peak rate of H/O/OH radical production or the heat release rate.