Year of Publication

2021

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department/School/Program

Mechanical Engineering

First Advisor

Dr. Jose Grana-Otero

Second Advisor

Dr. Michael Renfro

Abstract

Due to diverse applications of graphene, a kinetic mechanism describing rates of elementary reactions is extremely useful. To achieve that goal the elementary reactions need to be detected and their rates need to be determined. In this work the objectives are to use first-principle tools to find those reactions and analyze their paths in the context of graphene oxidation. Density functional theory (DFT) calculations provide the best approximation to the Schr\"{o}dinger equation, which is not feasible to solve analytically for large molecules like graphene. We have performed these calculations to find stable configurations (geometry optimization) and minimum energy paths between them. NEB calculations are performed to determine the activation energy of the reactions and the transition states structures. As a second part to this study, an application of a kinetic mechanism was investigated. Structure of a premixed planar hydrogen flame was analytically related to the distribution of OH* (electronically excited hydroxyl). The significance of this work lies in the fact that OH* is a commonly used intermediate species for diagnostic purposes. It is shown that OH* is perfectly reproduced by steady state and partial equilibrium approximations. Two regimes of fundamentally dissimilar kinetics are described for OH* and in each regime, approximate expressions are derived for the profiles of OH* concentration. In the end it is shown that changing the parameters like dilution rate and fuel air ratio in the flame can lead to changes in the ratio of the intensities in the reaction layer and in the post flame region. It is shown that this disproportionality can be used as a diagnostic means to locate the reaction layer.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2021.098

Funding Information

This study was supported largely through teaching assistantship (TA) at the University of Kentucky, Mechanical engineering (ME) and physics departments. For one semester, Fall of 2019, the funding was provided through research assistantship (RA) from the research grant awarded by the Air Force Office of Scientific Research under award number FA9550-18-1-0261. The detailed

2014: TA at ME department
2015: TA at ME department
2016: TA at ME department and Physics department
2017: TA at physics department for summer only (self-funded the rest of the year)
2018: TA at Physics department and ME department
2019: RA during the Fall semester and TA at ME department during the spring semester.
2020: TA at ME department

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