Some Theoretical Considerations on the Combustion and Disruption of Free Slurry Droplets

Abstract

Abstract The combustion and disruption or free slurry droplets are studied theoretically to elucidate a mechanism for the overall disruptive burning process. The disruptive burning process consists of three stages; a d2-law stage, a shell formation stage, and a disruption stage. It is proposed that the agglomeration of particles near the droplet surface due to capillary forces causes the shell formation and that the pyrolysis of additives due to the temperature rise in the outer surface of the shell produces an impermeable shell immediately and eventually disruption activity. A simple mathematical model is formulated to predict the shell formation and disruption time, and the fragmented shell thickness. The model simulation results for the disruptive burning of boron/JP-IO slurry droplets show good agreements with Takahashi er al. (1988a, b)'s experimental results. The disruption time increases with increasing initial slurry droplet diameter or increasing initial boron loading. The thickness of the fragmented shell increases as the initial diameter or the initial boron loading is increased. Finally, results show that the disruption time increases significantly whereas the thickness of the fragmented shell increases slightly as the environmental oxygen concentration is increased.