氨气/甲烷旋流火焰结构及NO_x 排放规律研究

Ammonia is identified as a promising fuel, because of the advantages of its carbon-free nature and well-established carriage and storage technique. However, NH₃ fuel is still facing several challenges which mainly include the difficulties to stabilize flames and the unacceptable huge NO_x emissions. In this study, the reacting flow fields and the flame structures of NH₃/air flames as well as NH₃/CH₄/air flames on low CH₄ blending ratio were measured. The turbulence intensity of two kinds of flames shows difference at the flame positions. The turbulence intensity of 90%NH₃ flame is higher than that of NH₃ flame. At the same bulk velocity, the effect of equivalence ratio on the NH₃ flame structure is mainly concentrated on the change of the flame height. A gas analyzer was used to measure the emissions. The addition of CH₄ increases the unburned NH₃ emission during equivalent ratio over 1.0, and also causes large CO and CO₂ emissions. The NO_x emissions of 90%NH₃ flame is higher than that of NH₃ flame. At the condition near equivalent ratio of 1.1, all emissions are relatively low, and the low methane blending ratio does not have a significant impact on this low emission position.