The melt processing of monodisperse and polydisperse polystyrene melts within a slit entry and exit flow

Experimental flow birefringence results and some pressure difference predictions were compared with numerical predictions. Two different computational approaches were followed, one using a viscoelastic integral K-BKZ/Wagner model within the finite element method solver Polyflow, and the other using the tube theory-based Pom-Pom constitutive equation and Lagrangian-Eulerian code flowSolve. Both numerical methods were able to capture certain experimental observations reasonably well in the stable flow regime, but were not able to predict the onset of the experimentally observed flow instabilities.