An experimental and modelling study of the combustion of oxygenated hydrocarbons

A chemical kinetic mechanism for the combustion of acetone has been developed and compared with a range of experimental data from the literature and with species concentration profiles measured in this study in the Princeton variable-pressure flow reactor. The current mechanism has been found to agree with the experimental data more accurately than the original mechanism. However, in the concentration profiles, ethylene and water are consistently over-predicted by the current mechanism. Ignition delay times of ethanol and dimethyl ether have been measured in the low-pressure shock tube at NUI, Galway at varying fuel concentrations, equivalence ratios and pressures. Laminar burning velocities of ethanol in air have been measured using the flat-flame burner at the Universite de Lorraine at 358 K and 1.0 atm. Reactions that influence the ignition delay times of ethanol and dimethyl ether include decomposition and hydrogen-abstraction reactions, while those influencing the laminar burning velocities of ethanol involve the secondary ethanol and acetaldehyde radicals. Diethyl ether has been studied in the low-pressure shock tube at equivalence ratios of 0.5, 1.0 and 2.0 and at pressures of 1.0 and 3.5 atm, while burning velocities of diethyl ether in air have been reported at 1.0 atm and at temperatures from 298 to 398 K. Unimolecular decomposition reactions have been found to affect the ignition delay times of diethyl ether, while hydrogen-abstraction reactions affect both ignition delay times and laminar burning velocities of the fuel. Dimethoxymethane has been investigated in the low- and high-pressure shock tubes at NUI, Galway at equivalence ratios of 0.5, 1.0 and 2.0 and at pressures from 1.0 to 9.0 atm. Laminar burning velocities of dimethoxymethane in air have been reported at a pressure of 1.0 atm and at temperatures from 298 to 358 K. The shock tube ignition delay times of dimethoxymethane at 9.0 atm have been compared with those obtained in a rapid compression machine, with NTC-like behaviour shown from 850 to 950 K. Ignition delay times of sec-butanol and isobutanol have been measured in the low-pressure shock tube at equivalence ratios of 0.5, 1.0 and 2.0 and at a pressure of 3.5 atm. Reactions that have an effect on the ignition delay times of both butanol isomers are decomposition and hydrogen-abstraction reactions. The decomposition of sec-butanol produces ethyl and secondary ethanol radicals, while that of isobutanol produces isopropyl and methoxy radicals and water and isobutene. Isopentanol in air has been investigated in the high-pressure shock tube at various equivalence ratios and at pressures of 7.0 and 20.0 atm. Hydrogen-abstraction reactions have been found to influence the ignition delay times of isopentanol at the conditions studied. The seven liquid isomers of pentanol in air have been studied in the flat-flame burner at atmospheric pressure and at a temperature of 358 K. 1-Pentanol has been found to be the most reactive isomer and 2-methyl-2-butanol the least. Laminar burning velocities of 2-methylfuran in air have been measured in the flat-flame burner at atmospheric pressure and at temperatures from 298 to 388 K, while those of 2,5-dimethylfuran in air have been measured in the same facility at the same pressure and at temperatures of 298 and 358 K. Reactions involving the parent fuel molecules have been found to greatly affect the laminar burning velocities, with hydrogen abstraction from the methyl groups and decomposition of the fuel being the most significant.2016-03-1