Study of Natural Gas/DME homogeneous charge compression ignition withuse of multi‐ dimensional CFD model and detailed chemical kinetics

In this study a multi‐dimensional Computational Fluid Dynamics (CFD) model is coupled with chemical reactionsto investigate the DME/Natural Gas Homogenous Charge Compression Ignition (HCCI) combustion and emissionsprocesses. A detailed chemical mechanism of DME with 79 species and 351 reactions has been used for chemicalkinetics. Performance and combustion process, NOx and CO emissions and rate of production and oxidation ofmajor in‐cylinder species with different DME addition is investigated. Results show that for the simultaneouslyfueling natural gas with the addition of DME the, ignition time is advanced and maximum pressure is increased.By increasing fraction of DME, the low‐temperature heat release is more pronounced as the addition of DME hasgreater effect on beginning stages of combustion than in later stages and the majority of DME is consumed beforeany oxidation of methane. Oxidation of methane is mainly caused by the high temperatures resulting from DMEcombustion. A noticeable amount of CO is formed as a result of first ignition. Oxidation of CO does not occur untilboth DME and methane are nearly consumed when combustion temperature is significantly high. With theaddition of DME, CO emission noticeably is reduced and NOx emission is increased strongly. The level of NOxemission for 30% DME addition is about 700 times of than 0% DME addition.

کلیدواژه ها:

HCCI ، NG/DME ، Computational Fluid Dynamics ، Detailed Chemical Kinetics