Influence of hydrogen addition on combustion characteristics of premixed laminar dimethyl ether flames

Premixed laminar dimethyl ether-hydrogen-air flames with different hydrogen addition ratios are investigated experimentally and numerically to reveal the influences of hydrogen addition on dimethyl ether combustion, including laminar flame rate, adiabatic flame temperature and free radicals in flame. The results show that with the increasing hydrogen addition ratio, laminar flame rate and adiabatic flame temperature of mixtures rise, the rising scope is smaller for hydrogen addition ratio lower than 80%, and greater for the ratio higher than 80%; a little amount of hydrogen is produced at the initial combustion stage for low hydrogen addition ratio, which means that dimethyl ether is oxidized previously in blended mixtures and the oxidization of dimethyl ether plays a dominant role in combustion; the fractions of free radicals increase with increasing hydrogen addition, and obviously increasing of H fraction significantly accelerates laminar flame rate for high hydrogen addition ratio.