Coupled interactive effects of ammonia and hydrogen additions on ethylene diffusion flames: A detailed kinetic study

In order to create effective combustion technologies and fuels with low or no carbon emissions, the research was conducted to assess the coupled interactive effects of NH3 and H2 additions on ethylene counterflow diffusion flames from a kinetic perspective. The effects of the NH3/H2 combination on flame temperatures, major species, key radicals, important intermediate species, representative oxygenated species and NOx were examined. The results of the study utilizing fictitious inert NH3 and/or H2 revealed the chemical effects of the two components. It was found that the NH3/H2 coupled effects had a more effective inhibitory effect on soot precursors than the effects of corresponding sum of single NH3 or H2 addition. The production of soot precursors was promoted by the coupled chemical effects of NH3 and H2, but the coupled dilution and thermal effects were observed to have a greater impact, resulting in a decrease of the mole fractions of soot precursors. As for the interaction of NH3 and H2 effects, the presence of H2 decreased the chemical effects of NH3 on the augmentation of C2H2, A1, A2, and CH3CHO mole fractions. The NH3 addition alleviated the H2 chemical effects on increasing C2H2, C3H3, A1 and A2 concentrations. Conversely, the NH3 chemical effects on C3H3, OH and CH3CHO were enhanced when H2 was added. The presence of NH3 augmented the chemical effects of H2 on the growth of OH mole fraction. Moreover, the H2 chemical effects hindered the production of NO and NO2 in the presence of NH3.