Combustion of propanol–glycerol mixture droplets in reduced gravity

Reduced-gravity experiments on combustion of propanol–glycerol mixture droplets were performed. Droplets were initially about 1 mm in diameter with initial glycerol mass fractions of 0, 0.05 and 0.2. All experiments were in air at standard temperature and pressure. Experiments showed flame contractions, and data on burning rates and onset times for flame contraction allowed effective species diffusivities to be estimated. Comparison of the experiments with computational modeling suggests that convective mixing was likely present in the droplets. Propanol–glycerol droplets sometimes exhibited extinction after flame contraction. This behavior has been previously observed only for much larger droplets burned in space-based experiments.