Heating Response Study of Aluminum Nanoparticles with Molecular Dynamics Simulations
Open Access
- Author:
- Rocca Bejar, Daniela
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 17, 2020
- Committee Members:
- Bladimir Ramos Alvarado, Thesis Advisor/Co-Advisor
Sean Michael Mcintyre, Committee Member
Karen Ann Thole, Program Head/Chair
Adrianus C Van Duin, Committee Member - Keywords:
- reaxff
Energetic materials
Molecular dynamics
Nanoparticle combustion - Abstract:
- The combustion of aluminum particles is a complex process involving physical and chemical changes that span several length scales. Three stages can be found during the combustion of aluminum nanoparticles: particle heating, ignition and oxidation. The objective of this project is to provide further insight into the process of aluminum particle ignition by investigating the heating response of non-oxidizing and isolated aluminum nanoparticles (Al-core/$\mathrm{Al_{2}O_{3}}$-shell system) via molecular dynamics simulations. The reaxff approach, a reactive force field, was used for the simulations because it can model chemical reactions. The results presented demonstrate reaxff's correct prediction of bulk aluminum and alumina structural properties through RDF calculations. Regarding the nanoparticles, the cohesive energy for different Al nanoparticle diameters was calculated and results agreed with theoretical predictions. Additionally, the melting point depression was captured for Al nanoparticles of decreasing diameter after applying different heating rates. In the literature, it is theorized that the particle's oxide layer cracks or melts upon ignition. The results obtained show that for an isolated particle, no fracture of the oxide shell occurs, instead the oxide shell and Al-core melt.