Combustion characteristics of primary reference fuel (PRF) droplets: Single stage high temperature combustion to multistage “Cool Flame” behavior

We report experiments and detailed numerical modeling of mixtures of primary reference fuel (PRF) droplets consisting of n-heptane and iso-octane with initial droplet diameters of 0.5 and 3.51 mm. The results show a quasi-steady, low temperature (or “Cool Flame” (CF)) droplet burning mode that stems from a varying two-stage chemical kinetic behavior of the combustion chemistry. The simulations further illustrate, that the CF droplet burning mode...