ANALYSIS METHODS FOR DIRECT NUMERICAL SIMULATIONS OF PRIMARY BREAKUP OF SHEAR-THINNING LIQUID JETS

The goal of this work is to improve our understanding of the primary breakup of jets from shear-thinning non-Newtonian liquids. We use direct numerical simulations (DNS) with the volume of fluid method for tracking of the liquid phase and piecewise linear interface calculations for a sharp interface reconstruction. We calculate the shear-thinning viscosity with the Carreau-Yasuda model. We use the inflow velocity profile as well as the shear-thinning properties as varying parameters for different simulations. Different methods of investigation are presented and applied to the simulations. We visualize and describe the influence of shear-thinning viscosity on the breakup process. We quantify the breakup over the liquid surface area and show the influence of different inflow velocities and different shear-thinning viscosities on the breakup. The investigation is refined by analyzing quantities, which define the deformation of the jet surface. A new visualization method is used to track the temporal development of liquid mass. With these methods for analysis we lay a foundation to quantitatively compare different destabilizing parameters and to estimate droplet sizes resulting from the breakup. The combination of these analysis helps to provide a better understanding of shear-thinning breakup in general and brings us closer to predicting resulting droplet sizes.