engleski

Comparison of reduced chemical kinetics models of ammonia combustion in the experimental burner

Chemical mechanisms of ammonia combustion are important for the development of ammonia combustion systems, but also as a mean of investigation of harmful NOx emissions, so they can be minimized. Despite of large body of experimental and modelling work on the topic of ammonia combustion, there is still need for further investigation of combustion kinetics that will encompass wide range of operating conditions in terms of temperature, pressure and equivalence ratio. Taking the above stated, the object of this work is further numerical study of ammonia combustion chemistry under practical industrial conditions. After literature review, three reduced mechanisms of ammonia combustion were used for simulation of experimental premixed swirl burner with the aim of evaluating their performance. Through the analysis of temperature field reduced Mathieu mechanism was identified to be the worst one due to the fact that it was prominently different compared to other two models. Reduced mechanism based on the chemistry from Okafor proved to be the best in terms of emissions, as it was able to capture both measured trend and quantities with satisfactory accuracy. Neither one of the models was able to capture experimentally recorded ammonia slip, with discrepancies becoming especially high after equivalence ration increased over the value of 1. It is expected that this study will contribute to enhance the current knowledge by providing new insights in ammonia burning conditions closely resembling those in industrial applications and consequently help to design real industrial burning systems.

ammonia ; NOx ; sustainable combustion ; CFD ; reduced chemical kinetics ; premixed swirl burner

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