Reduced mechanism identification and cool flame analysis of ammonia/dimethyl ether premixed combustion

Both ammonia and dimethyl ether (DME) are renewably low-carbon fuels, and their blend is a promising alternative for modern energy and transportation systems. The identification of accurate reaction mechanisms is essential to reveal NH 3 /DME combustion performance. By removing unimportant species and revisiting kinetic parameters of key reactions, this work develops the most simplified chemical mechanism reported so far, featuring 50 species and 212 reactions, whose fidelity is shown to be quite satisfactory over a range of combustion regimes. It is found that the predictive ability of the reduced mechanism is more satisfying with elevated inlet pressures. The temperature and pressure exponents of laminar burning velocities are also analyzed. Further, as low-temperature ignition properties are concerned, the agreement between experimental data and predictions by the proposed model is generally equal to, or better than, that of other reaction mechanisms. Finally, it is applied to preliminarily shed light on cool flame and emission characteristics. Different combustion characteristics under ultra-lean and rich conditions are identified, characterized by radicals’ formation and temperature profiles, which have important implications for engine ignition and flame stability. In general, the simplified mechanism has a wide versatility and provides an efficient alternative means for the interpretation of NH 3 /DME combustion.