Numerical Investigation on the Emission Reduction Characteristics of the Turbulent Premixed Ammonia/air Flames Stabilized by a Swirl Burner

摘要

The present study was conducted to numerically investigate the emission reduction characteristics of turbulent premixed ammonia (NH_3)/air flames stabilized by a swirl burner, using a large eddy simulation with a detailed chemistry. Even though, in the stoichiometric condition, NO emission of the NH_3/air flames is much higher than that of ordinary hydrocarbon fuels, the study found that, in rich flame conditions, NO emission is significantly decreased, whereas unburnt NH_3 emission increases with respect to the equivalence ratio. This emission reduction characteristics of turbulent H_3/air flames almost agrees with a one-dimensional study. However, for shorter residence time of NH_3/air mixture, unburnt NH_3 emission has much discrepancies than that of one-dimensional estimations. Then, the study found that unburnt NH_3 emission linearly depends on the Damkohler number which associates the fluid and chemical time scales, whereas NO emission solely depends on the equivalence ratio.