Abstract
Ignition delay times from undiluted mixtures of natural gas (NG)/H2/Air and NG/NH3/Air were measured using a high-pressure shock tube at the University of Central Florida. The combustion temperatures were experimentally tested between 1000-1500 K near a constant pressure of 25 bar. Mixtures were kept undiluted to replicate the same chemistry pathways seen in gas turbine combustion chambers. Recorded combustion pressures exceeded 200 bar due to the large energy release, hence why these were performed at the high-pressure shock tube facility. The data is compared to the predictions of the NUIGMech 1.1 mechanism for chemical kinetic model validation and refinement. An exceptional agreement was shown for stoichiometric conditions in all cases but strayed at lean and rich equivalence ratios, especially in the lower temperature regime of H2 addition and all temperature ranges of the baseline NG mixture. Hydrogen addition also decreased ignition delay times by nearly 90%, while NH3 fuel addition made no noticeable difference in ignition delay time. NG/NH3 exhibited similar chemistry to pure NG under the same conditions, which is shown in a sensitivity analysis, demonstrating hydrogen chemistry to be dominant in NG/H2 mixtures and hydrocarbon chemistry to be dominant in NG/NH3 mixtures. The reaction CH3 + O2 = CH3O + O is identified and suggested as a possible modification target to improve model performance. Increasing the robustness of chemical kinetic models via experimental validation will directly aid in designing next-generation combustion chambers for use in gas turbines, which in turn will greatly lower global emissions and reduce greenhouse effects.
Notes
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Graduation Date
2023
Semester
Summer
Advisor
Vasu Sumathi, Subith
Degree
Master of Science in Aerospace Engineering (M.S.A.E.)
College
College of Engineering and Computer Science
Department
Mechanical and Aerospace Engineering
Degree Program
Aerospace Engineering; Thermofluid Aerodynamic Systems
Identifier
CFE0009768; DP0027876
URL
https://purls.library.ucf.edu/go/DP0027876
Language
English
Release Date
August 2024
Length of Campus-only Access
1 year
Access Status
Masters Thesis (Open Access)
STARS Citation
Pierro, Michael, "A High-Pressure Shock Tube Study of Hydrogen and Ammonia Addition to Natural Gas for Reduced Carbon Emissions in Power Generation Gas Turbines" (2023). Electronic Theses and Dissertations, 2020-2023. 1786.
https://stars.library.ucf.edu/etd2020/1786