Ammonia is considered as a renewable fuel. However, ammonia combustion suffers from two major issues which are preventing its practical application. One is that ammonia flame is very unstable and can easily get extinguished. The other issue is its high emission, which pollutes the environment. In this project, a collaborative team will investigate using plasma (electric discharge) to enhance ammonia combustion process and reduce emission at the same time. The plasma-ammonia combustion interaction has not been studied previously. This award will investigate the underlying physical and chemical processes using experimental and computational tools. The new insights gained from experimental data will be used to develop computational models that can be used in research related to renewable energy. In this project, undergraduate and graduate students will receive hands-on training in experimental and computational skills. They become new contributors to the science, technology, engineering, and mathematics (STEM) workforce of United States. Significant opportunities exist at both University of Minnesota and Georgia Institute of Technology to engage underrepresented students and researchers.

The goal of this project is to understand the physical and chemical processes to stabilize ammonia flames and reduce NOx emission simultaneously by non-equilibrium plasma. This project has two key hypotheses: (1) prompt ammonia oxidation/decomposition introduced by plasma enhances flame; (2) the production of NH and NH2 from plasma reduces NOx emission. Accordingly, the scope and objectives of this proposed research are: (i) investigation of fundamental ammonia plasma chemical kinetics to understand its prompt dissociation and oxidation induced by plasma at different values of reduced electric field (E/N). This will be achieved by conducting experiments in a flow reactor with speciation measurement and one-dimensional (1D) numerical simulations with detailed plasma and combustion chemical kinetics; (ii) investigation of interactions between plasma kinetics and flame dynamics (including lean blow-off and thermoacoustic combustion instability) by conducting experiments in a model gas turbine combustor using NH, NH2, NO and OH planar laser induced fluorescence (PLIF) and three-dimensional (3D) direct numerical simulations (DNS) with a simplified plasma model deduced from detailed 1D modeling. The experimental work will be conducted by the Georgia Institute of Technology team and the numerical work will be conducted by the University of Minnesota team.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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University of Minnesota Twin Cities
United States
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