Combustion and Emission Characteristics of NH3/H2/Air Premixed Gas Under Wall Effects

Zero-carbon fuels have garnered significant attention in the context of carbon neutrality and peak carbon emissions. A numerical model utilizing computational fluid dynamics (CFDs) software integrated with detailed chemical reaction mechanisms is established to investigate the premixed combustion process of ammonia/hydrogen/air under wall effects and it is validated by comparing experimental results. As the equivalence ratio increases from 0.6 to 1.2, the peak temperature at the wall stagnation point rises. At the same time, the combustion reaction intensifies, and the higher temperature leads to an increase in the concentration of OH radicals near the wall. As the hydrogen blending ratio increases from 0.5 to 0.8, the overall peak temperature increases. The increase in the hydrogen blending ratio in the fuel enhances the intensity of combustion, resulting in a decrease in the height of the premixed cone, and the rise in temperature weakens the inhibitory effect of wall heat dissipation on nitric oxide (NO) generation, resulting in an increase in NO emissions near the wall.