Date of Award
Master of Science (MS)
This research study is a theoretical framework for understanding rapid thermal processes which occur during the performance of new Nanoenergetic Gas-Generators (NGG) systems that rapidly release a large amount of gaseous products and generate a fast-moving thermal wave during the explosion. The kinetics of rapid oxidation of metal nanoparticles acquires practical importance with the quickly developing nanoenergetic systems. The thin film oxidation theory of Cabrera-Mott model was examined for a spherically symmetric case and used to analyze the physical importance of the exothermic processes for prediction of the reaction time and front velocity. A rapid kinetic of oxide growth on the outer part of oxide layer of aluminum ions during the oxidation of a spherical aluminum nanoparticle was evaluated by using the Cabrera - Mott moving boundary mechanism with self-heating process. The electrical potential was determined and correlated to the reaction time, which a leads to the solution of a nonlinear Poisson equation in a moving boundary domain. Motion of the boundary is determined by the gradient of a solution on the boundary (via a Gibbs factor). We have considered an accurate self-heating model of particle oxidation based on the balance of energy released as a result of chemical reaction. We have used detailed modeling of the heat loss, which is mainly due to convection. We investigated this problem numerically, using COMSOL and MATLAB for detailed air convection dynamics. It was demonstrated that the oxidation rates dramatically increased as a combined effect of nonlinearity and self-heating.
University of Texas Brownsville