Inhibition of Laminar Premixed Flames of Dimethyl Ether by a Phosphorus-Containing Compound

The present paper reports experimental and modeling results on the laminar burning velocity and structure of stoichiometric and fuel-rich premixed laminar flames of DME with and without TMP additives. The spatial variations of the mole fractions of H, OH, PO, PO2, HOPO, HOPO2 and some intermediate hydrocarbons in the one-dimensional burner-stabilized flames with various equivalence ratios are measured by the flame-sampling molecular beam mass spectrometry. The novel measurement data for the DME flames are used to validate a kinetic mechanism available in the literature for flame inhibition by organophosphorus compounds. The TMP inhibition effectiveness of DME flames has been determined and revealed to be lower than that of CH4/air flame. The speeds of CH4/air and DME/air flames were found to be sensitive to the same reactions involving phosphorus compounds, while the sensitivity of the methane flame speed to inhibition reactions is higher than that of DME/air flame. The observed differences were explained by the higher concentration of the chain carriers H, OH, and O in the DME flame. Based on the results obtained, we conclude that the phosphorus-containing inhibitors are promising candidates for reducing the flammability and ensuring the fire safety of DME mixtures with air.