Simulating the Homogeneous Charge Compression Ignition Process Using a Detailed Kinetic Model for Dimethyl Ether (DME) and Methane Dual Fuel

With a zero-dimensional detailed chemical kinetic model, a numerical study was carried out to investigate the chemical reaction phenomena encountered in the homogenous charge compression ignition process of dimethyl ether (DME) and methane dual fuel. The results show that the DME/methane dual fuel elementary reactions affect each other. The low temperature reaction (LTR) of DME is inhibited, the second molecular oxygen addition of DME is restrained, and β -scission plays a dominant role in DME oxidation. Hydrogen peroxide (H₂O₂) is controlled by DME oxidation and almost has no correlation with methane oxidation. The rich H₂O₂ concentration makes methane oxidation occurs at low initial temperature. Most of the formaldehyde (CH₂O) is produced from H-abstraction of methoxy (CH₃O) rather than from LTR of the DME. However, the heat release of methane oxidation promotes the hot flame reactions of DME which make the reactions with high activation energy occur. OH comes from many different ways rather than Based on the sensitivity analysis of chemical reactions, the major paths of the DME/methane HCCI reaction occurring in the engine cylinder were clarified.

Key words: homogeneous charge compression ignition (HCCI), dimethyl ether (DME), methane, detailed chemical kinetic model