Mathematical modeling of three-dimensional die flows of viscoplastic fluids with wall slip

The mathematical modeling of the continuous processing of filled polymers, and concentrated suspensions in screw extruders and dies of complex shapes is undertaken. The simulation of the flow of such filled systems in complex geometries is rendered complicated by the occurrence of wall slip at fluid/solid boundaries. The incorporation of wall slip in the analysis of three-dimensional flows including flows through dies, single/twin-screw extruders and other processing geometries is currently lacking. Here we present an analysis of three-dimensional flows with wall slip, and demonstrate the procedure using the flow of a Herschel-Bulkley fluid in a tapered die.