Modeling Combustion of Ammonia/Hydrogen Fuel Blends under Gas Turbine Conditions

To utilize ammonia as an alternative fuel for future power generation, it is essential to develop combustion chemical kinetic mechanisms which can describe in some detail the reaction characteristics and combustion properties. In the present study, a detailed chemical-kinetics mechanism is developed to validate premixed combustion characteristics of ammonia and hydrogen fuel blends comprehensively. In order to obtain a useful model for gas turbine applications, the proposed kinetic mechanism is verified in terms of NOx emission, laminar burning velocity, and ignition delay times, focusing particularly on elevated conditions which are encountered during gas turbine operation. Results have shown that the proposed kinetic model performs with satisfactory accuracy under different practical equivalence ratio conditions. The comparison with other mechanisms from the literature also demonstrates that the model can comprehensively describe the reaction process of ammonia/hydrogen fuels in terms of different combustion properties especially under gas turbine conditions. Finally, to develop the kinetic model for more practical applications, the proposed mechanism is reduced and appraised in a 2D large-eddy-simulation representing turbulent combustion for ammonia/hydrogen fuels under gas turbine conditions. The reduced mechanism shows good agreement with the parent model, while offering considerably greater computationally efficiency, hence providing optimizm for the application of detailed ammonia chemistry for future CFD analysis under gas turbine combustion conditions.