A comparative study of the high-temperature autoignition of methyl butanoate and n-heptane is carried out behind reflected shock waves. The ignition delay times of both fuels are compared at constant argon-to-oxygen ratios, equivalence ratios, and pressures. It is found that both hydrocarbons have comparable high-temperature ignition behavior under stoichiometric conditions in line with recent observations for longer chain alkanes and modeling results for methyl esters. However, differences are observed in the effect of equivalence ratio. Whereas the effect of equivalence ratio at constant argon/oxygen ratio on n-heptane ignition delay times is weak, its effect on methyl butanoate ignition is more appreciable. Representative experimental results from this study are compared with simulations using the most recent chemical kinetic mechanisms for the oxidation of methyl butanoate and the n-heptane mechanism by Curran et al. (Curran, H.; Gaffuri, P.; Pitz, W.; Westbrook, C. Combust. Flame 1998, 114, 149-177) While there is good agreement at stoichiometric conditions, the models deviate from experiment under rich conditions. Correlations are obtained by linear regression of the data from this study. The correlation format is also applied to numerical simulation results, thereby providing an alternative method for assessing the relative performance of chemical kinetic models.
ASJC Scopus subject areas
- General Chemical Engineering
- Fuel Technology
- Energy Engineering and Power Technology