Numerical simulation of secondary breakup of shear-thinning droplets

TL;DR

This paper uses numerical simulations to investigate how shear-thinning non-Newtonian properties influence the secondary breakup process of droplets, revealing significant effects on deformation and breakup regimes.

Contribution

It introduces a new definition of the Ohnesorge number considering shear rate and compares shear-thinning and Newtonian droplet breakup behaviors.

Findings

Shear-thinning alters the effective viscosity distribution inside droplets.

Shear-thinning properties change droplet deformation and morphology.

Breakup regime transitions are affected by non-Newtonian properties.

Abstract

The breakup of non-Newtonian droplets is ubiquitous in numerous applications. Although the non-Newtonian property can significantly change the droplet breakup process, most previous studies consider Newtonian droplets, and the effects of the non-Newtonian properties on the breakup process are still unclear. This study focuses on the secondary breakup of shear-thinning droplets by numerical simulation. The volume of fluid method is used to capture interface dynamics on adaptive grids. To compare shear-thinning droplets and Newtonian droplets, a new definition of the Ohnesorge number is proposed by considering the characteristic shear rate in the droplet induced by the airflow. The results show that compared with the Newtonian fluid, the shear-thinning properties can change the effective viscosity distribution inside the droplet, alter the local deformation, change the droplet morphology, and affect the transition in the droplet breakup regime.