UNDERSTANDING AMMONIA/HYDROGEN FUEL COMBUSTION MODELING IN A QUIESCENT ENVIRONMENT

Ammonia and Hydrogen are attractive alternative fuels for a zero-carbon combustion solution that can rapidly decarbonize the transportation industry. Understanding the chemical behavior and combustion characteristics of these fuels individually, as well as blended together, is pivotal to ensuring their widespread adoption and utilization. Furthermore, in the era of computer-aided engineering, it is critical to evaluate our ability to computationally model the chemical reactivity of these two fuels and validate predictions of experimentally observed phenomena using multi-dimensional simulations. In this study, ammonia/hydrogen chemical kinetics mechanisms available from the research literature are investigated through 0-D, 1-D, and 3-D simulations. The 0-D and 1-D simulations were carried out to understand the ignition delay and laminar flame speeds, respectively, at different operating pressures and temperatures. 3-D simulations were also performed to test the fuels’ behavior in a closed volume combustion chamber. The multi-dimensional computational results were compared against optically measured experimental data available in recent publications. Specifically, a comparison of unstretched flame speeds determined from stretched flame speeds of post-processed computational results is made. Lean and rich combustion limits have been computationally evaluated as well. Lastly, observed physical buoyancy effects were reproducible in a quiescent computational environment leading to increased confidence in using the evaluated chemical kinetics mechanisms for high-fidelity reciprocating piston engine computational research and development.