Detailed numerical simulations of the autoignition of single n-heptane droplets in air

The autoignition process of single n-heptane droplets in air is simulated for spherical symmetry and at constant
pressure. Using a detailed transport model and detailed chemical kinetics, the governing equations of the two
phases are solved in a fully coupled way. The ambient gas temperature is varied from 600 to 2000 K. Simulations
are performed for isobaric conditions. The initial droplet radius ranges from 10 to 200 μm. The influence of
different physical parameters, such as ambient pressure, droplet radius, or initial conditions, on the ignition delay
time and the location of the ignition is investigated. The gas temperature turns out to be the parameter dominating
the ignition process. The droplet temperature shows a minor influence on the ignition delay time. The influence
of the droplet radius on the ignition delay shows a high sensitivity to other ambient conditions, such as ambient
temperature and pressure.