Shock-induced aerobreakup of a polymeric droplet

Droplet atomization through aerobreakup is omnipresent in various natural and industrial processes. Atomization of Newtonian droplets is a well-studied area; however, non-Newtonian droplets have received less attention despite their being frequently encountered. By subjecting polymeric droplets of different concentrations to the induced airflow behind a moving shock wave, we explore the role of elasticity in modulating the aerobreakup of viscoelastic droplets. Three distinct modes of aerobreakup are identified for a wide range of Weber number (similar to 10(2)-10(4)) and elasticity number (similar to 10(-4)-10(2)) variation: these modes are vibrational, shear-induced entrainment and catastrophic breakup modes. Each mode is described as a three-stage process. Stage I is droplet deformation, stage II is the appearance and growth of hydrodynamic instabilities and stage III is the evolution of liquid mass morphology. It is observed that elasticity plays an insignificant role in the first two stages but a dominant role in the final stage. The results are described with the support of adequate mathematical analysis.

Automated summary

This study investigates the aerobreakup of non-Newtonian droplets under the influence of airflow. Polymeric droplets of different concentrations were subjected to induced airflow behind a moving shock wave to explore the role of elasticity in modulating the aerobreakup of viscoelastic droplets. Three distinct modes of aerobreakup were identified, namely vibrational, shear-induced entrainment, and catastrophic breakup, for a wide range of Weber number and elasticity number variation. Each mode is described as a three-stage process, including droplet deformation, appearance and growth of hydrodynamic instabilities, and evolution of liquid mass morphology. The results suggest that elasticity plays a dominant role in the final stage of the aerobreakup process.