A kinetics and dynamics study on the auto-ignition of dimethyl ether at low temperatures and low pressures

Though the combustion chemistry of dimethyl ether (DME) has been widely investigated over past decades, there remains a dearth ignition data that examines low-temperature, low-pressure DME. In this study, DME/‘air’ mixtures at various equivalence ratios from lean (0.5) to extremely rich (5.0) were ignited behind reflected shock waves fixed pressure (3.0 atm) temperature range 625–1200 K. The behavior is different high-pressures, with repeatable delay time fall-off feature observed experimentally in transition zone negative coefficient (NTC) regime high-temperature regime. This could not be reproduced using available kinetic mechanisms as conventionally homogeneous simulations. shows strong ratio dependence and disappears completely an 5.0. A local kernel postulate was implemented numerically quantifiably examine inhomogeneous premature ignition. At low temperature, no pre-ignition occurs mixture. conspicuous discrepancy between measurements constrained UV simulations temperatures beyond NTC third O2 addition reaction sub-set incorporated into AramcoMech 3.0, together related species thermochemistry calculated G3/G4/CBS-APNO compound method, explore low-temperature deviation. new class does influence model predictions IDTs, but updated does. Sensitivity analyses indicate decomposition hydroperoxy-methylformate plays critical role improving oxidation mechanism DME unfortunately, thermal rate never previously investigated. Further experimental theoretical endeavors are required attain holistic quantitative chemical kinetics based on our understanding