Numerical and experimental studies of ethanol flames

Ethanol combustion is investigated on the basis of a new chemical-kinetic mechanism consisting of 192 elementary steps among 36 species, augmented by 53 additional steps and 14 additional species to address the formation of oxides of nitrogen and 43 steps and 7 species to address formation of compounds involving three carbon atoms. The mechanism is tested against shock-tube autoignition-delay data, laminar burning velocities, counterflow diffusion-flame extinction and measurements of structures of counterflow partially premixed and diffusion flames, the last of these newly completed and reported here for the first time. These measurements, on ethanol-air flames at a strain rate of 100 s(-1), employing prevaporized ethanol with a mole fraction of 0.3 in a nitrogen carrier stream, were made for the pure diffusion flame and for a partially premixed flame with a fuel-side equivalence ratio of 2.3 and involved thermocouple measurements of temperature profiles and determination of concentration profiles of C2H5OH, CO, CO2, H-2, H2O, O-2, N-2, CH4, C2H6 and C2H2 + C2H4 by gas chromatographic analysis of samples withdrawn through fine quartz probes. Computational investigations also were made of profiles of oxides of nitrogen and other potential pollutants in similar partially premixed flames of ethanol and other fuels for comparison purposes. The computational results are in reasonable agreement with experiment and perform as well as or better than predictions of other, generally much larger, mechanisms available in the literature. Further research is, however, warranted for providing additional and more stringent tests of the mechanism and its predictions. (C) 2006 The Combustion Institute. Published by Elsevier Inc. All rights reserved.