Keywords
Direct Numerical Simulation, Volume of Fluid, Droplet Combustion, Droplet Evaporation, Aluminum Droplet
Abstract
This thesis focuses on the direct numerical simulation of the combustion of a single aluminum droplet with phase change. For this purpose, the Volume of Fluid (VOF) method is employed for the direct numerical simulation of two distinct phases. To model the droplet combustion, the phase change (evaporation) and chemical reactions are modeled by setting source terms for each governing equation. This work proposes a new form of species source term by phase change, derived using the local instant formulation of two-phase flow.
The Stefan problem is used to verify the modified source term. Evaporation fluxes calculated with both modified and conventional sources are compared, demonstrating that the modified species source term yielded mass flow rates closer to theoretical values, with an error rate of less than 20%. The instabilities of source terms in the droplet case are also analyzed, revealing that surface tension and chemical reactions cause numerical errors arising from the sharp discontinuities at the interfacial cells.
The model’s validation includes a comparison with a benchmark case, assessing the temporal evolution of droplet diameter change and temperature fields. While the diameter change aligns reasonably with the benchmark, the temperature fields do not reach the benchmark’s flame temperature due to numerical diffusions. Furthermore, the molar fraction of aluminum gas at the interface closely matches experimental values, although the overall spatial distribution of molar fraction of species does not align with the benchmark.
Completion Date
2024
Semester
Summer
Committee Chair
Kinzel, Michael
Degree
Master of Science (M.S.)
College
College of Engineering and Computer Science
Department
Mechanical and Aerospace Engineering
Degree Program
Aerospace Engineering
Format
application/pdf
Identifier
DP0028579
URL
https://purls.library.ucf.edu/go/DP0028579
Language
English
Release Date
8-15-2024
Length of Campus-only Access
None
Access Status
Masters Thesis (Open Access)
Campus Location
Orlando (Main) Campus
STARS Citation
Lim, Soomin, "Development and Evaluation of DNS of Aluminum Droplet Combustion Using the VOF Approach" (2024). Graduate Thesis and Dissertation 2023-2024. 375.
https://stars.library.ucf.edu/etd2023/375
Accessibility Status
Meets minimum standards for ETDs/HUTs