Low-Temperature Autoignition of Diethyl Ether/O2 Mixtures: Mechanistic Considerations and Kinetic Modeling

Abstract

Abstract Autoignition processes are of fundamental kinetic importance as well as of practical relevance for combustion devices. In recent years, diethyl ether (DEE) has attracted increasing attention as a diesel additive and also serves as a test compound in fire-safety-related studies. In the present work, a kinetically parameterized reaction mechanism for the autoignition of DEE is developed. It consists of a DEE-specific part supplemented by a base mechanism taken from the literature that contains the C1/C2 hydrocarbon and the H2/O2 reaction systems. The complete mechanism is validated against experimental ignition delay times available from the literature for temperatures ranging from 500 to 1300 K and reactant pressures between 3 and 5 bar (T=500−900 K) and between 10 and 40 bar (T=900−1300 K). The absolute values and the temperature dependence of the ignition delay times are satisfactorily reproduced. This includes important autoignition characteristics such as one- and two-stage ignitions and the so-called negative temperature coefficient regime where ignition delay times increase with temperature. Detailed kinetic-mechanistic explanations for all these phenomena are given.