Development of a reduced combustion model for ammonia/hydrogen combustion

Abstract

Ammonia/hydrogen receives increasing interest as a carbon-free fuel in novel combustion techniques. Simulation aided design often requires coupling of flow field and chemical kinetics, whose feasibility relies essentially on an affordable (reduced) reaction model. However, existing ammonia/hydrogen reduced models are scarce and cannot reasonably reproduce available experimental data over a comprehensive set of conditions. Hence, a reduced ammonia/hydrogen model was developed in the present work using a combined method: the directed relation graph with error propagation method was applied first followed by a contribution to species production/consumption screening method. The model reduction method substantially reduces the size of the model, from 37 species and 237 reactions to 25 species and 108 reactions. The reduced model was compared to available reduced models over a comprehensive set of experimental data, including ignition delay time measurements in shock-tube and rapid compression machine, laminar flame speed measurements and species profile data measured in jet stirred reactor and burner stabilized flame. The obtained model maintains comparable prediction accuracy compared to the detailed model and is superior to the other reduced models.