Numerical investigation on the combustion characteristics and NOx emission of non-premixed H2/NH3/air in vase-shaped micro combustor.

Hydrogen and ammonia, as currently popular zero carbon fuels, have received widespread attention. These two fuels have complementary advantages in combustion characteristics, cost, safety, etc. Based on the vase shaped micro combustor, a new structure proposed for application in micro thermophotovoltaic systems in our previous work. This article numerically investigated the combustion characteristics and NOx emission of non-premixed H 2 /NH 3 /Air in vase shaped micro combustor which proposed in our previous work. The variation patterns of flame temperature, wall temperature, flammability limit, and NOx emission with the blended ratio of NH 3 and equivalence ratio were obtained. It was found that the flame cannot move and stabilize when the mixing ratio is 0.6. The rate of production (ROP) and sensitivity of NO and N 2 O were analyzed. Four precursors of NO, HNO, NH, N, N 2 have been discovered. Under the conditions of this article, HNO is the key component affecting NO emissions. When the blending ratio is greater than 0.3, the lower reaction rate of HNO leaded to a decrease in NO. The elementary reaction R63: NH + NO N 2 O + H is the key elementary reaction that affects NO consumption and N 2 O generation. The blending ratio of 0.4 and the equivalence ratio of 1.2 are the optimized operating conditions with the highest comprehensive performance. • Combustion and emission characteristics of H 2 /NH 3 in vase shaped micro combustor. • H 2 /NH 3 non-premixed combustion limit in novel micro combustor was studied. • ROP and sensitivity of NO and N 2 O were analyzed. • HNO and R63 are key species and elementary reaction effect on the NO emission. [ABSTRACT FROM AUTHOR]