| dc.description.abstract | Multiphase detonations are phenomena involving multiple coupled systems evoking fundamental thermodynamic, hydrodynamic, heat/mass transfer, and chemical questions that require in depth analyses to provide insight into the what, where, when, why, and how of the complex process. Of particular interest in this work is the multiphase detonation phenomena involving wave propagation through liquid hydrocarbon fuel droplets and gaseous oxidizers. The success of a multiphase detonation in this context, from which the detonation strength and stability are of major interest, is dependent on the heat and mass transfer processes of the droplet in relation to the chemical burning time scales at play required for detonability. Fuel droplet heat and mass transfer under detonation conditions is driven primarily by evaporation and droplet breakup. With evaporation, breakup, and chemical burning occurring on similar time scales, a competition begins for which process will dominate properties of the detonation.
Multiphase detonations will be investigated from a numerical perspective. An open-source computational fluid dynamics code, FLASH, will be utilized for the analysis with the end result being full scale, two-dimensional simulations. This work aims to expand both on the code capabilities and comprehension of work done at the Texas A&M University Fluid Mixing at Extreme Conditions Laboratory. Global, single-step reactions will be expanded to a more general two-step formulation of an irreversible reaction (CnHm + n + H2O) paired with one reversible reaction (CO + 1O2 ←→ CO2) applicable for air combustion. Zero-dimensional model verification will be presented along with one- and two-dimensional results implemented into the FLASH code. Droplet vaporization will be investigated through a new model that examines different modes of burning and combines available reduced order models. Comparisons to previous work done with n-dodecane-oxygen detonations will be provided. The capabilities presented in this work lay the foundation for future multiphase detonation simulations capable of resolving spatial variance in equivalence ratio and different droplet burning regimes. | |
