Effects of Airflow Velocity and Droplet Diameter on the Secondary Breakup Characteristics

Abstract

In this paper, the volume of fluid method coupled with adaptive mesh refinement technology is adopted to investigate the effects of the initial airflow velocity and droplet diameter on deformation and breakup characteristics of the n-Octane droplet for Weber numbers in the range of 125 to 325. The result indicates that the shear breakup mode whose mechanism is similar to the “stretched ligament breakup” occurs at different Weber numbers in the present simulations. Still, droplets have significantly different deformation and breakup characteristics even at the same Weber number. The dimensionless cross-stream and streamwise diameters turn into approximately and in the final stage of deformation, respectively. Indeed, as the Weber number increases, the extents of cross-stream and streamwise deformations are relatively weaker before the parent droplet breakup. Finally, both dimensional and dimensionless initial breakup times are directly proportional to the initial droplet diameter but inversely proportional to the initial airflow velocity, demonstrating that increasing initial airflow velocity can promote the droplet breakup but increasing initial droplet diameter can delay the droplet breakup.