Numerical simulation of a free-falling liquid sodium droplet combustion

Droplet combustion is considered one of the combustion figurations in sodium-fire events; the detailed combustion mechanism by which it occurs is evaluated by a developed computational fluid dynamic (CFD) simulation code, called COMET, in which the extended MAC method is employed for calculating the reacting compressible flow coupled with the multi-component diffusion of chemical species. A single droplet combustion in steady-airflow was simulated using the COMET to analyze: (1) the spatial distributions of heat rate and temperature, and (2) the formation, decomposition, and transfer of combustion products. Next, a free-falling droplet combustion experiment was simulated for code validation, where the evaluated falling-velocity and burnt-mass showed good agreement with the experimental values.