Study of extinction properties in dimethyl ether diffusion flames (1st report, effects of equilibrium flame temperature and flame structure on extinction properties)

Recently many issues related to automotive engineering, such as the environment and energy problems have gained attention. These social-related issues are giving impetus to the adoption of urgent measures such as alternative fuels and new combustion techniques for the internal combustion engines. In this context, dimethyl ether is thought to be a potential alternative to diesel fuel, as it has lower overall pollutant emissions and better economy. On the other hand, oxygen-enriched combustion has been gaining acceptance as an environmental friendly combustion, because this can reduce soot and NO x emission. The purposes of this paper are to examine the extinction properties of DME flames and the feasibility concerning the application of oxygen-enriched combustion to DME flames using a counterflow burner. Firstly, the strain rate at extinction is measured for dimethyl ether and propane flames as a function of equilibrium flame temperature under the same flame structure. Secondly, the strain rate at extinction is also measured under the condition that the flame structures are changed, but the equilibrium flame temperatures are not varied. In addition, numerical calcula tions are also performed using detailed chemical-kinetic mechanism to obtain value for extinction and compared with measurements.