The conflicting role of shear thinning and extensional thickening on corner vertex within entry flow for branched and filled polymer melts

Vortex growth is related to the extensional thickness viscosity of polymer melts flowing through contractions, whereas the shear thinning viscosity results in no significant vortex. The nonlinearity of extensional viscosity in relation to molecular architectures and additive composition compositions is usually more sensitive than shear viscosity. Recently, the proposed GNF-X (Generalized Newtonian Fluid eXtended) of the weighted shear/extensional viscosity has been incorporated in the state-of-the-art CFD (computational fluid dynamics) framework to show the extension-induced vortex growth. Using GNF-X, it is important to investigate the conflicting role of shear thinning and extensional thickening on vortex sizes in 3D (three-dimensional) contraction flow simulations for branched and filled polymers melts. In particular, one demonstrates that the long-branched polymers and fiber-filled polymers strongly increase the vortex size, which is consistent with the related experimental observations.