Investigation on the oxidation chemistry of methanol in laminar premixed flames

Abstract

In this work, oxidation chemistry of methanol was investigated in laminar premixed flames. Laminar burning velocities of methanol/air mixtures at 423K and 1–10atm were measured in a spherical combustion vessel, extending the range of equivalence ratio up to 2.1. A stoichiometric premixed flat flame of methanol/O2/Ar at 0.04atm was also conducted using synchrotron VUV photoionization mass spectrometry (SVUV-PIMS) to obtain more detailed kinetic information. Particularly, fuel-derived radicals including methoxy radical and hydroxymethyl radical were observed, while formaldehyde (CH2O) and formic acid (HOCHO) were identified as the abundantly produced intermediates in methanol flame. A methanol model was developed and validated against the experimental data obtained in this work, as well as in literature. In the predictions of laminar burning velocities, HO2 radical plays an important role under very rich conditions. Besides, the measurement of formaldehyde and formic acid in methanol flame is helpful to constrain the rate constant of CH2OH+O2=CH2O+HO2, which presents large uncertainties at high temperatures.