Measurements and modeling study of intermediates in ethanol and dimethy ether low-pressure premixed flames using synchrotron photoionization

Abstract

A molecular-beam flame-sampling photoionization mass spectrometer, employing synchrotron radiation, was applied to detect new intermediates and to measure mole fractions in the low-pressure laminar premixed stoichiometric ratio dimethyl ether (DME)/O 2/Ar and ethanol/O 2/Ar flames respectively. With the help of the means mentioned above, flame species of the two fuels, including isomeric intermediates, were unambiguously identified and the temperature profiles and mole fraction profiles of intermediates were also compared and analyzed. Additionally, five detailed oxidation mechanisms were applied to the modeling study to verify current mechanism for the two fuels. Based on the comparative experimental and modeling study of the two flames at low pressure, the oxidation mechanism for DME and ethanol was revised and a new one was suggested in the present work. The results calculated by the revised mechanism showed that the modeling prediction agreed with those experimental results measured in DME and ethanol flames as well as with the ones in five flames from the experiments done by the other people. In the measurement all species with mole fraction higher than 10 −4 were considered, including those which have not been included in the present five mechanisms. Meanwhile, the mole fractions of the species which had not been considered by current mechanism such as ethenol, acetone and ethyl methyl ether (EME) were also included in the modeling study. Besides, the reaction paths and species conversion ratio analysis were also conducted to show the difference before and after the mechanism revised.