Multicomponent fuel droplet evaporation using 1D Global Rainbow Technique

The accurate characterization of droplet evaporation requires measurement of both the size variation (evaporation rate) and the temperature/composition evolution. To obtain the evaporation rate of moving droplets, a nanometer diameter change must be quantified on droplets of several dozens of microns, moving at a few meters per second. This paper used an innovative optical technique, 1D Global Rainbow Technique, to characterize locally the evaporation of gasoline droplets by measuring the droplet evaporation rate and refractive index (i.e. temperature and composition). The information on the refractive index and the droplet size are extracted from the angular rainbow position and from the rainbow shape, respectively, while the evaporation rate is extracted from the ripple structure angular shift.