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 was employed for the direct numerical simulation of two distinct phases. Furthermore, this work proposes a new form of species source term induced by phase change, based on the local instant formulation of two-phase flow. In VOF approach, source terms in the governing equations were implemented to model the phase change and combustion of the aluminum droplet. The implementation of these source terms was compared and verified against the analytic solution of the Stefan problem and experimental data. For verification, the Stefan problem was set up, and the modified species source terms with the VOF method were implemented. The results demonstrated that the modified species source term yielded mass flow rates closer to theoretical values, with an error rate of less than 20%. The direct numerical simulation of an aluminum droplet with the modified species source term also reflected similar evaporation times. Temperature profiles and combustion products of Al droplet were obtained and compared with experimental data. Although the application of the source terms introduced instability in terms of interface smearing, the variations in fluid properties were validated and showed results matching experimental data.
Michael Kinzel, Committee Chair.
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