Adaptation of a PTV method for droplets evaporating in vicinity of a flame

Measuring the time and length of fuel droplet evaporation provides a better understanding of spray dynamics. When a droplet evaporates, it is increasingly difficult to detect it, and therefore it is difficult to track it with a Particle Tracking Velocimetry (PTV) algorithm. To solve this problem, classical PTV algorithms were adapted by exploiting the image of the droplet at frame N to find it in frame N+1. In addition, Interferometric Laser Imaging Droplet Sizing (ILIDS) was used to measure the droplets' physical size from the images collected for the PTV. This new algorithm was applied to a counter-current burner with dodecane droplets evaporating on an air-methane flame. Particle Image Velocimetry (PIV) was used to measure the air velocity field and the temperature field by Rayleigh measurement. The treatment of the data collected during the experiment shows that the PTV algorithm followed the droplets during all their evaporation phase, which would have been very challenging for a classical PTV algorithm. Moreover, since droplets evaporate in a high-temperature environment, it is impossible to track their physical size from ILIDS obtained with a continuous wave laser source. Therefore the follow-up of the droplet during its all evaporating phase was necessary. [GRAPHICS] .

Automated summary

Measuring the time and length of fuel droplet evaporation provides a better understanding of spray dynamics. A new algorithm combining PTV and ILIDS was developed to track the droplets and measure their physical size. Experimental results show that the algorithm successfully follows the droplets during their entire evaporation phase.